ORCID Profile
0000-0002-4490-4138
Current Organisations
University of Liverpool
,
University of Western Australia
,
Murdoch University
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Publisher: European Respiratory Society (ERS)
Date: 03-1995
DOI: 10.1183/09031936.95.08030463
Abstract: Threshold loading is a method of incrementally loading the inspiratory muscles, which requires development of an adjustable threshold pressure (Pth) before air will flow. In the ideal device, flow is independent of pressure once Pth is exceeded. A "weighted plunger" apparatus is commonly used, but devices described previously perform unreliably at high inspiratory load. We have modified this apparatus using the diaphragm and valve seating from a threshold valve used to deliver positive airway pressure (AMBU 10, AMBU International, Denmark) to yield improved pressure-flow characteristics. With this device, there was a linear relationship between Pth and weight on the plunger (r = 0.998), and flow was largely independent of pressure once Pth was exceeded: pressure developed at an inspiratory flow of 1.3 +/- 0.1 l.s-1 was 13.6 +/- 7.0% below Pth. Our modified weighted plunger apparatus allows consistent and reliable threshold loading of inspiratory muscles, even at high inspiratory loads.
Publisher: Wiley
Date: 16-12-2014
DOI: 10.1111/RESP.12443
Publisher: Springer Science and Business Media LLC
Date: 26-08-2021
Publisher: Elsevier
Date: 2023
Publisher: Wiley
Date: 15-02-2011
DOI: 10.1111/J.1365-2869.2010.00843.X
Abstract: Repetitive airway occlusion during sleep in patients with obstructive sleep apnoea (OSA) results in the generation of negative intrathoracic pressures and ends in arousal, both of which may predispose to reflux during sleep (nocturnal reflux). We aimed to determine and compare the prevalence of nocturnal reflux symptoms and their sleep-associated risk factors in untreated OSA patients, OSA patients using continuous positive airway pressure (CPAP) therapy, and the general population. Gastro-oesophageal reflux and sleep questionnaires were completed by 1116 patients with polysomnography diagnosed OSA and by 1999 participants of the 2007 Busselton population health survey. Of the OSA patients, 137 completed the reflux questionnaire before and after treatment. Risk of OSA in the general population was assessed using the Berlin score. The prevalence of frequent (>weekly) nocturnal reflux symptoms was increased (P<0.001) in OSA patients (10.2%) versus the general population (5.5%), in in iduals from the general population at high (8.7%) versus low risk (4.3%) of OSA and in patients with severe (13.9%) versus mild OSA (5.1%). Frequent nocturnal reflux symptoms were associated with high risk (general population) (OR 1.9, P<0.01) and severity of OSA (OSA population) OR 3.0, severe versus mild OSA, P<0.001) after correcting for age, gender and body mass index. Treatment with CPAP decreased the prevalence of reflux symptoms significantly. In conclusion, the prevalence of nocturnal reflux symptoms is increased in those with or suspected of having OSA. This association is independent of other risk factors including age, gender and body mass index, suggesting a causal relationship between OSA and nocturnal reflux.
Publisher: Oxford University Press (OUP)
Date: 14-08-2017
DOI: 10.1093/SLEEP/ZSX136
Abstract: New noninvasive ventilation (NIV) modes can automatically adjust pressure support settings to deliver effective ventilation in response to varying ventilation demands. It is recommended that fixed expiratory positive airway pressure (FixedEPAP) is determined by attended laboratory polysomnographic (PSG) titration. This study investigated whether automatically determined EPAP (AutoEPAP) was noninferior to FixedEPAP for the control of obstructive sleep apnea (OSA) during intelligent volume-assured pressure support (iVAPS) treatment of chronic hypoventilation. In this randomized, double-blind, crossover study, patients with chronic hypoventilation and OSA used iVAPS with AutoEPAP or FixedEPAP over two separate nights of attended PSG. PSG recordings were scored by an independent scorer using American Academy of Sleep Medicine 2012 criteria. Twenty-five adults (14 male) with chronic hypoventilation secondary to obesity hypoventilation syndrome (n = 11), chronic obstructive pulmonary disease (n = 9), or neuromuscular disease (n = 5), all of whom were on established home NIV therapy, were included (age 57 ± 7 years, NIV for ≥3 months, apnea-hypopnea index [AHI] >5/hour). AutoEPAP was noninferior to FixedEPAP for the primary outcome measure (median [interquartile range] AHI 2.70 [1.70-6.05]/hour vs. 2.40 [0.25-5.95]/hour p = .86). There were no significant between-mode differences in PSG sleep breathing and sleep quality, or self-reported sleep quality, device comfort, and patient preference. Mean EPAP with the Auto and Fixed modes was 10.8 ± 2.0 and 11.8 ± 3.9 cmH2O, respectively (p = .15). In patients with chronic hypoventilation using iVAPS, the AutoEPAP algorithm was noninferior to FixedEPAP over a single night's therapy.
Publisher: SPIE
Date: 05-10-2009
DOI: 10.1117/12.835797
Publisher: Frontiers Media SA
Date: 19-07-2021
DOI: 10.3389/FPSYT.2021.688672
Abstract: Study Objectives: To determine cognitive profiles in in iduals with short sleep duration insomnia (SSDI) and normal sleep duration insomnia (NSDI also, paradoxical insomnia), compared to healthy sleepers. Method: Polysomnographic (PSG) and neuropsychological data were analysed from 902 community-based Raine Study participants aged 22 ± 0.6 years of whom 124 met criteria for insomnia (53 with NSDI and 71 with or SSDI) and 246 were classified as healthy with normal sleep (i.e., without insomnia or other sleep disorders). Measurements of self- report (attention and memory) and laboratory-assessed (attention, episodic memory, working memory, learning, and psychomotor function) cognition and mood, and PSG-based sleep stages (% total sleep time %TST) were compared between these 3 groups. Results: In comparison to the healthy sleeper group, both insomnia groups had poorer self-reported attention, memory, mood, and sleep, and poorer laboratory-assessed attention (inconsistency). The NSDI group had less consistent working memory reaction time than healthy-sleepers or those with SSDI. The SSDI group had more inconsistency in executive function (shifting), and showed greater %TST in stage N1 and N3, and less REM sleep than either healthy-sleepers or those with NSDI. Conclusions: In iduals with NSDI demonstrated greater working memory inconsistency, despite no laboratory assessed sleep problems, implicating early signs of pathophysiology other than disturbed sleep. Those with SSDI demonstrated different sleep architecture, poorer attention (inconsistency), and greater executive function (inconsistency) compared to healthy-sleepers and those with NSDI, implicating sleep disturbance in the disease process of this phenotype.
Publisher: Springer Berlin Heidelberg
Date: 2008
Publisher: American Physiological Society
Date: 12-1997
DOI: 10.1152/JAPPL.1997.83.6.1923
Abstract: Smith, C. A., K. S. Henderson, L. Xi, C.-M. Chow, P. R. Eastwood, and J. A. Dempsey. Neural-mechanical coupling of breathing in REM sleep. J. Appl. Physiol. 83(6): 1923–1932, 1997.—During rapid-eye-movement (REM) sleep the ventilatory response to airway occlusion is reduced. Possible mechanisms are reduced chemosensitivity, mechanical impairment of the chest wall secondary to the atonia of REM sleep, or phasic REM events that interrupt or fractionate ongoing diaphragm electromyogram (EMG) activity. To differentiate between these possibilities, we studied three chronically instrumented dogs before, during, and after 15–20 s of airway occlusion during non-REM (NREM) and phasic REM sleep. We found that 1) for a given inspiratory time the integrated diaphragm EMG ([Formula: see text]Di) was similar or reduced in REM sleep relative to NREM sleep 2) for a given[Formula: see text]Di in response to airway occlusion and the hyperpnea following occlusion, the mechanical output (flow or pressure) was similar or reduced during REM sleep relative to NREM sleep 3) for comparable durations of airway occlusion the [Formula: see text]Di and integrated inspiratory tracheal pressure tended to be smaller and more variable in REM than in NREM sleep, and 4) significant fractionations (caused visible changes in tracheal pressure) of the diaphragm EMG during airway occlusion in REM sleep occurred in ∼40% of breathing efforts. Thus reduced and/or erratic mechanical output during and after airway occlusion in REM sleep in terms of flow rate, tidal volume, and/or pressure generation is attributable largely to reduced neural activity of the diaphragm, which in turn is likely attributable to REM effects, causing reduced chemosensitivity at the level of the peripheral chemoreceptors or, more likely, at the central integrator. Chest wall distortion secondary to the atonia of REM sleep may contribute to the reduced mechanical output following airway occlusion when ventilatory drive is highest.
Publisher: Research Square Platform LLC
Date: 18-09-2023
Publisher: Wiley
Date: 25-01-2005
DOI: 10.1111/J.1464-5491.2005.01458.X
Abstract: The incidence of Type 2 diabetes is increasing, along with its associated micro- and macrovascular disease manifestations. Previous studies indicate that patients with Type 2 diabetes exhibit abnormal cardiopulmonary reflex responses to various stimuli, although the impact of hypoxia, a common physiological stimulus, on ventilatory responses has not previously been studied in humans with Type 2 diabetes. Minute ventilation (V(E)) breathing pattern responses (total breath time, T(TOT) expiratory time, T(E) inspiratory time, T(I) inspiratory duty cycle, T(I)/T(TOT)) were measured during 5 min each of normoxia and isocapnic hypoxia (arterial O2 saturation approximately 85%) in eight subjects with Type 2 diabetes and seven age- and body mass index-matched healthy subjects. During normoxia, V(E) was similar in control and diabetic subjects (6.4+/-1.2, 6.4+/-1.1 l/min, respectively). In response to hypoxia, V(E) significantly increased in both groups (to 17.0+/-5.0 and 9.5+/-2.0 l/min, respectively, P<0.05), but the magnitude of increase in V(E) was significantly less in diabetic than in control subjects (P<0.05). In addition, the breathing pattern response to hypoxia differed between groups in terms of T(I)/T(TOT) and T(TOT) (P<0.05), with control subjects significantly decreasing T(TOT) and T(E) (P<0.05) while diabetic subjects tended to increase both. Relative to matched control subjects, Type 2 diabetic subjects exhibit blunted V(E) responses to acute isocapnic hypoxia, suggesting that this group of diabetic subjects possesses a chemoreflex ill-equipped to respond homeostatically to hypoxic challenge.
Publisher: Wiley
Date: 05-1992
Abstract: The sensitivity of non-isotopic in situ hybridization (NISH), particularly on formalin-fixed, paraffin-embedded (FFPE) clinical tissues, has been the subject of controversy. Generally, NISH has been regarded as being less sensitive than radiolabelled procedures, although some reports have contradicted this. Accordingly, tissues from mice which were transgenic for variable amounts of the human alpha-1-antitrypsin gene were used to optimize the NISH procedure and to estimate the sensitivity. This approach showed that prolonged incubation of slides in final substrate resulted in high sensitivity--about 13 kb of target DNA. However, this prolonged incubation crucially depended on achieving minimal non-specific background staining. Many factors affected the degree of background staining, but five were particularly important. First, the method of mounting cut sections onto slides. Second, the length of the probe (ideally less than 400 bp). Third, the procedure for proteolytic digestion. Fourth, the denaturation technique, and fifth, the quality of the dextran sulphate used in the hybridization mix. The optimized protocol showed variable patterns of mRNA distribution in the transgenic mouse livers, while DNA distribution appeared uniform.
Publisher: Elsevier BV
Date: 08-2019
Publisher: BMJ
Date: 03-2020
DOI: 10.1136/BMJOPEN-2019-033440
Abstract: Eye diseases and visual impairment more commonly affect elderly adults, thus, the majority of ophthalmic cohort studies have focused on older adults. Cohort studies on the ocular health of younger adults, on the other hand, have been few. The Raine Study is a longitudinal study that has been following a cohort since their birth in 1989–1991. As part of the 20-year follow-up of the Raine Study, participants underwent a comprehensive eye examination. As part of the 27- and 28-year follow-ups, eye assessments are being conducted and the data collected will be compared with those of the 20-year follow-up. This will provide an estimate of population incidence and updated prevalence of ocular conditions such as myopia and keratoconus, as well as longitudinal change in ocular parameters in young Australian adults. Additionally, the data will allow exploration of the environmental, health and genetic factors underlying inter-subject differential long-term ocular changes. Participants are being contacted via telephone, email and/or social media and invited to participate in the eye examination. At the 27-year follow-up, participants completed a follow-up eye screening, which assessed visual acuity, autorefraction, ocular biometry and ocular sun exposure. Currently, at the 28-year follow-up, a comprehensive eye examination is being conducted which, in addition to all the eye tests performed at the 27-year follow-up visit, includes tonometry, optical coherence tomography, funduscopy and anterior segment topography, among others. Outcome measures include the incidence of refractive error and pterygium, an updated prevalence of these conditions, and the 8-year change in ocular parameters. The Raine Study is registered in the Australian New Zealand Clinical Trials Registry. The Gen2 20-year, 27-year and 28-year follow-ups are approved by the Human Research Ethics Committee of the University of Western Australia. Findings resulting from the study will be published in health or medical journals and presented at conferences. ACTRN12617001599369 Active, not recruiting.
Publisher: SPIE
Date: 20-02-2020
DOI: 10.1117/12.2545282
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2020
DOI: 10.1213/ANE.0000000000004070
Abstract: The propensities for the upper airway to collapse during anesthesia and sleep are related, although much of our understanding of this relationship has been inferred from clinical observation and indirect measures such as the apnea–hypopnea index. The aim of this study was to use an identical, rigorous, direct measure of upper airway collapsibility (critical closing pressure of the upper airway) under both conditions to allow the magnitude of upper airway collapsibility in each state to be precisely compared. Ten subjects (8 men and 2 women mean ± SD: age, 40.4 ± 12.1 years body mass index, 28.5 ± 4.0 kg/m 2 ) were studied. Critical closing pressure of the upper airway was measured in each subject on separate days during (1) propofol anesthesia and (2) sleep. Critical closing pressure of the upper airway measurements were obtained in all 10 subjects during nonrapid eye movement sleep and, in 4 of these 10 subjects, also during rapid eye movement sleep. Critical closing pressure of the upper airway during anesthesia was linearly related to critical closing pressure of the upper airway during nonrapid eye movement sleep ( r = 0.64 [95% CI, 0.02–0.91] n = 10 P = .046) with a similar tendency in rapid eye movement sleep ( r = 0.80 [95% CI, −0.70 to 0.99] n = 4 P = .200). However, critical closing pressure of the upper airway during anesthesia was systematically greater (indicating increased collapsibility) than during nonrapid eye movement sleep (2.1 ± 2.2 vs −2.0 ± 3.2 cm H 2 O, respectively, n = 10 within-subject mean difference, 4.1 cm H 2 O [95% CI, 2.32–5.87] P .001) with a similar tendency during rapid eye movement sleep (1.6 ± 2.4 vs −1.9 ± 4.3 cm H 2 O, respectively, n = 4 unadjusted difference, 3.5 cm H 2 O [95% CI, −0.95 to 7.96] P = .087). These results demonstrate that the magnitude of upper airway collapsibility during anesthesia and sleep is directly related. However, the upper airway is systematically more collapsible during anesthesia than sleep, suggesting greater vulnerability to upper airway obstruction in the anesthetized state.
Publisher: Frontiers Media SA
Date: 12-2016
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 03-2013
Publisher: Informa UK Limited
Date: 14-02-2018
DOI: 10.1080/02640414.2017.1287936
Abstract: The aim of the present study was to investigate the influence of different types of tasks performed with or without an electronic device (tablet) on pre-sleep alertness, subsequent sleep quality and next-day athletic performance. Eight highly trained netball players attended a sleep laboratory for pre-sleep testing, polysomnographic sleep monitoring and next-day physical performance testing on 5 separate occasions (1 familiarisation and 4 experimental sessions). For 2 h prior to bedtime, athletes completed cognitively stimulating tasks (puzzles) or passive tasks (reading) with or without a tablet. Sleepiness tended to be greater after reading compared to completing puzzles without a tablet (d = 0.80), but not with a tablet. Melatonin concentration increased more so after reading compared to completing puzzles on a tablet (P = 0.02). There were no significant differences in sleep quality or quantity or next-day athletic performance between any of the conditions. These data suggest that using a tablet for 2 h prior to sleep does not negatively affect subsequent sleep or next-day performance in athletes.
Publisher: Elsevier BV
Date: 12-2006
Abstract: Upper airway (UA) patency during inspiration is determined by the balance between dilating forces generated by UA dilator muscle activity and collapsing forces related to the decreased intraluminal pressure that accompanies flow generated by inspiratory muscle activity. It is possible that the relative strengths of UA dilator and inspiratory pump muscles could be an important determinant of the susceptibility to UA collapse during sleep (ie, obstructive sleep apnea [OSA]). Measurements of tongue protrusion (TP) force and maximum inspiratory pressure (Pimax) were obtained in 94 patients admitted for overnight polysomnography for suspected OSA, quantified by apnea-hypopnea index (AHI). There was a direct linear relationship between TP force and Pimax (r(2) = 0.37, p 20/h) was not observed in any in idual with a ratio above this threshold. AHI was not linearly related to TP force, Pimax, or the ratio of TP force to Pimax. UA muscle strength is linearly related to inspiratory pump muscle strength. The ratio of UA muscle strength (TP force) and inspiratory pump muscle strength (Pimax) was not different between in iduals with and without OSA however, a high wakeful ratio of TP force to Pimax appears to be associated with a reduced propensity to moderate-to-severe OSA.
Publisher: Oxford University Press (OUP)
Date: 2018
DOI: 10.1373/CLINCHEM.2017.280701
Abstract: Associations between dairy intake and body mass index (BMI) have been inconsistently observed in epidemiological studies, and the causal relationship remains ill defined. We performed Mendelian randomization (MR) analysis using an established dairy intake-associated genetic polymorphism located upstream of the lactase gene (LCT-13910 C/T, rs4988235) as an instrumental variable (IV). Linear regression models were fitted to analyze associations between (a) dairy intake and BMI, (b) rs4988235 and dairy intake, and (c) rs4988235 and BMI in each study. The causal effect of dairy intake on BMI was quantified by IV estimators among 184802 participants from 25 studies. Higher dairy intake was associated with higher BMI (β = 0.03 kg/m2 per serving/day 95% CI, 0.00–0.06 P = 0.04), whereas the LCT genotype with 1 or 2 T allele was significantly associated with 0.20 (95% CI, 0.14–0.25) serving/day higher dairy intake (P = 3.15 × 10−12) and 0.12 (95% CI, 0.06–0.17) kg/m2 higher BMI (P = 2.11 × 10−5). MR analysis showed that the genetically determined higher dairy intake was significantly associated with higher BMI (β = 0.60 kg/m2 per serving/day 95% CI, 0.27–0.92 P = 3.0 × 10−4). The present study provides strong evidence to support a causal effect of higher dairy intake on increased BMI among adults.
Publisher: Oxford University Press (OUP)
Date: 10-2023
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/J.RMED.2003.07.005
Abstract: Progressive threshold loading (PTL) is a common test of respiratory muscle endurance. Healthy naive subjects improve endurance with successive exposures to PTL by altering their breathing responses, thus necessitating a familiarization period before reproducible measures can be obtained. This study sought to determine whether a similar "learning effect" is evident in patients with COPD, and what the mechanism of any such effect may be. Ten subjects with COPD (FEV1 34+/-13% predicted) underwent PTL on four occasions (>24 h apart). During PTL measurements were obtained of breathing pattern and maximum threshold pressure (Pthmax) achieved. Maximum inspiratory pressure (PImax) was measured on each occasion. Over the four tests PImax improved by 21+/-16% (SD) (P<0.05) and Pthmax by 32+/-21% (P<0.05) with a plateau in these measures achieved by test three. Pthmax/PImax was unchanged, being 61+/-11% at test one and 67+/-12% at test four. In contrast to healthy subjects, PTL was not associated with increased expiratory time or decreased end-expiratory lung volume. In contrast to PImax and Pthmax, which changed with successive tests, a single measure of the ratio Pthmax/PImax may present a useful guide to the endurance capacity of the respiratory muscles in patients with COPD.
Publisher: European Respiratory Society (ERS)
Date: 25-11-2022
DOI: 10.1183/13993003.01788-2021
Abstract: Recent advances in obstructive sleep apnoea (OSA) pathophysiology and translational research have opened new lines of investigation for OSA treatment and management. Key goals of such investigations are to provide efficacious, alternative treatment and management pathways that are better tailored to in idual risk profiles to move beyond the traditional continuous positive airway pressure (CPAP)-focused, “one size fits all” trial-and-error approach, which is too frequently inadequate for many patients. Identification of different clinical manifestations of OSA (clinical phenotypes) and underlying pathophysiological phenotypes (endotypes) that contribute to OSA have provided novel insights into underlying mechanisms and have underpinned these efforts. Indeed, this new knowledge has provided the framework for precision medicine for OSA to improve treatment success rates with existing non-CPAP therapies such as mandibular advancement devices and upper airway surgery, and newly developed therapies such as hypoglossal nerve stimulation and emerging therapies such as pharmacotherapies and combination therapy. Additionally, these concepts have provided insight into potential physiological barriers to CPAP adherence for certain patients. This review summarises the recent advances in OSA pathogenesis, non-CPAP treatment, clinical management approaches and highlights knowledge gaps for future research. OSA endotyping and clinical phenotyping, risk stratification and personalised treatment allocation approaches are rapidly evolving and will further benefit from the support of recent advances in e-health and artificial intelligence.
Publisher: American Physiological Society
Date: 02-2010
DOI: 10.1152/JAPPLPHYSIOL.00511.2009
Abstract: Regulation of airway caliber by lung volume or bronchoconstrictor stimulation is dependent on physiological, structural, and mechanical events within the airway wall, including airway smooth muscle (ASM) contraction, deformation of the mucosa and cartilage, and tensioning of elastic matrices linking wall components. Despite close association between events in the airway wall and the resulting airway caliber, these have typically been studied separately: the former primarily using histological approaches, the latter with a range of imaging modalities. We describe a new optical technique, anatomical optical coherence tomography ( aOCT), which allows changes at the luminal surface (airway caliber) to be temporally related to corresponding dynamic movements within the airway wall. A fiber-optic aOCT probe was inserted into the lumen of isolated, liquid-filled porcine airways. It was used to image the response to ASM contraction induced by neural stimulation and to airway inflation and deflation. Comparisons with histology indicated that aOCT provided high-resolution images of the airway lumen including mucosal folds, the entire inner wall (mucosa and ASM), and partially the cartilaginous outer wall. Airway responses assessed by aOCT revealed several phenomena in “live” airways (i.e., not fixed) previously identified by histological investigations of fixed tissue, including a geometric relationship between ASM shortening and luminal narrowing, and sliding and bending of cartilage plates. It also provided direct evidence for distensibility of the epithelial membrane and anisotropic behavior of the airway wall. Findings suggest that aOCT can be used to relate changes in airway caliber to dynamic events in the wall of airways.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2005
DOI: 10.1097/00000542-200509000-00007
Abstract: This study investigated the effect of varying concentrations of propofol on upper airway collapsibility and the mechanisms responsible for it. Upper airway collapsibility was determined from pressure-flow relations at three concentrations of propofol anesthesia (effect site concentration = 2.5, 4.0, and 6.0 mug/ml) in 12 subjects spontaneously breathing on continuous positive airway pressure. At each level of anesthesia, mask pressure was transiently reduced from a pressure sufficient to abolish inspiratory flow limitation (maintenance pressure = 12 +/- 1 cm H2O) to pressures resulting in variable degrees of flow limitation. The relation between mask pressure and maximal inspiratory flow was determined, and the critical pressure at which the airway occluded was recorded. Electromyographic activity of the genioglossus muscle (EMGgg) was obtained via intramuscular electrodes in 8 subjects. With increasing depth of anesthesia, (1) critical closing pressure progressively increased (-0.3 +/- 3.5, 0.5 +/- 3.7, and 1.4 +/- 3.5 cm H2O at propofol concentrations of 2.5, 4.0, and 6.0 microg/ml respectively P & 0.05 between each level), indicating a more collapsible upper airway (2) inspiratory flow at the maintenance pressure significantly decreased and (3) respiration-related phasic changes in EMGgg at the maintenance pressure decreased from 7.3 +/- 9.9% of maximum at 2.5 microg/ml to 0.8 +/- 0.5% of maximum at 6.0 microg/ml, whereas tonic EMGgg was unchanged. Relative to the levels of phasic and tonic EMGgg at the maintenance pressure immediately before a decrease in mask pressure, tonic activity tended to increase over the course of five flow-limited breaths at a propofol concentration of 2.5 microg/ml but not at propofol concentrations of 4.0 and 6.0 microg/ml, whereas phasic EMGgg was unchanged. Increasing depth of propofol anesthesia is associated with increased collapsibility of the upper airway. This was associated with profound inhibition of genioglossus muscle activity. This dose-related inhibition seems to be the combined result of depression of central respiratory output to upper airway dilator muscles and of upper airway reflexes.
Publisher: SPIE
Date: 07-02-2008
DOI: 10.1117/12.774887
Publisher: Oxford University Press (OUP)
Date: 04-2018
Publisher: Wiley
Date: 10-2019
DOI: 10.1111/JSR.70_12912
Publisher: Wiley
Date: 03-2006
DOI: 10.1111/J.1440-1843.2006.00820.X
Abstract: The 6-min walk test (6MWT) is commonly used to assess the functional exercise capacity of in iduals with cardiopulmonary disease. Recent studies have established regression equations to predict the 6-min walk distance (6MWD) in healthy Caucasian populations however, regression equations have yet to be established for the Singaporean population. The aim of this study was to determine 6MWD in healthy Singaporeans and identify contributors to 6MWD in this population. We also compared measured 6MWD with predicted 6MWD from two regression equations derived in Caucasian subjects. Thirty-five healthy subjects (32 Chinese, 16 men) aged between 45 and 85 years performed three walking tests using a standardized protocol. 6MWD was defined as the greatest distance achieved from the three tests. Heart rate (HR) was recorded each minute during the 6MWT. Other measurements included age, height, leg length, smoking history and self-reported physical activity. 6MWD was 560 +/- 105 m and was not significantly different between men and women (P = 0.19). 6MWD was related to age (r = -0.36, P = 0.03), height (r = 0.35, P = 0.04), leg length (r = 0.38, P = 0.02) and the maximum HR achieved on the 6MWT when expressed as a percentage of the predicted maximum HR (%predHRmax, r = 0.73, P < 0.001). Stepwise multiple regression analysis showed that age, height, weight and %predHRmax were independent contributors (P < 0.01) to 6MWD, explaining 78% of the variance. Predicted 6MWD using regression equations derived from Caucasian subjects exceeded measured 6MWD by more than 75 m (P < 0.001). This is the first study to report 6MWD for healthy Singaporeans aged 45-85 years. The regression equation developed in this study explained 78% of the variance in 6MWD. Published equations derived from Caucasian subjects overestimate 6MWD in Singaporean Chinese.
Publisher: Oxford University Press (OUP)
Date: 11-2015
DOI: 10.5665/SLEEP.5162
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.RMED.2018.11.013
Abstract: In people with moderate-to-severe chronic obstructive pulmonary disease (COPD), the minimal detectable difference (MDD) in endurance shuttle walk test (ESWT) performance following exercise training is unclear. We sought to determine the MDD for ESWT performance following supervised ground-based walking training using anchor- and distribution-based approaches and report whether these values exceeded random variation in test performance. Participants with COPD trained for 30-45 min, 2-3 times weekly for 8-10 weeks. The ESWT was performed before and after the training period. Immediately after training, participants rated their change in walking ability using a Global Rating of Change scale. Receiver Operating Characteristic curves were used to derive the value that best separated those who perceived their improvement in walking ability to be at least 'a little' better from 'almost the same, hardly any change'. These values were compared with those calculated using a distribution-based method. Random variation in test performance was defined as the minimal detectable change (MDC), calculated using the standard error of measurement. 78 participants (aged 70 ± 8 yr and FEV The MDD established using the anchor- and distribution-based approaches differed considerably. Large variation in test performance cautions against using the MDD to interpret changes in an in idual. Australian New Zealand Clinical Trials Registry (ACTRN12609000472279).
Publisher: Springer Science and Business Media LLC
Date: 03-2019
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.SMRV.2017.03.005
Abstract: Obstructive sleep apnea (OSA) is a nocturnal breathing disorder that is associated with cognitive impairment. The primary determinants of cognitive deficits in OSA are thought to be sleep disruption and blood gas abnormalities. Cognitive impairment is also seen in other disorders that are characterised primarily by sleep disturbance (e.g., sleep restriction/deprivation, insomnia) or hypoxia/hypercarbia (e.g., chronic obstructive pulmonary disease (COPD)). Assessment of the cognitive deficits observed in these other disorders could help better define the mechanisms underlying cognitive deficits in OSA. This study utilised meta-review methodology to examine the findings from systematic reviews and meta-analyses of the effects of untreated OSA, COPD, insomnia, and sleep deprivation on cognitive function in adults, compared with norms or controls. Eighteen papers met inclusion criteria: seven in OSA, two in insomnia, five in COPD, and four in sleep deprivation. OSA and COPD were both accompanied by deficits in attention, memory, executive function, psychomotor function, and language abilities, suggesting that hypoxia/hypercarbia may be an important determinant of deficits in these domains in OSA. Both OSA and sleep deprivation studies were accompanied by deficits in attention and memory, suggesting that short-term sleep disturbance in OSA may contribute to deficits in these domains. Visuospatial deficits were unique to OSA, suggesting the contribution of a mechanism other than sleep disturbance and hypoxia/hypercarbia to this problem. Our findings suggest that the cognitive deficits associated with untreated OSA are multidimensional, with different physiological disturbances responsible for differing cognitive problems.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2008
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.APMR.2010.06.010
Abstract: Reduced inspiratory muscle strength is common in people with chronic obstructive pulmonary disease (COPD) and is associated with dyspnea and decreased exercise capacity. Most studies of inspiratory muscle training (IMT) in COPD have demonstrated increased inspiratory muscle strength. Many have also shown improvements in dyspnea and exercise capacity. However, a persisting challenge when translating and applying the findings of these studies in clinical practice is the disparity in training loads, modalities, and outcomes measures used in the different studies. This commentary summarizes our clinical and research experience with a threshold IMT device with the aim of providing clinicians interested in prescribing IMT in this population with practical recommendations regarding patient selection, assessment, and implementation of training. We propose using an interval-based high-intensity threshold IMT program for people who are unable to participate fully in whole-body exercise training because of comorbidities such as severe musculoskeletal problems. Initial training loads equivalent to at least 30% of a person's maximum inspiratory pressure (PImax) are required for all people undertaking IMT. Supervision, which includes monitoring of oxygen saturation throughout the first training session, is recommended, and patients are warned to expect transient delayed-onset muscle soreness, a consequence of muscle adaptation to an unaccustomed activity. We recommend training be undertaken 3 times a week for 8 weeks, with loads progressively increased as symptoms permit. It is prudent to exclude people at risk of pneumothorax or spontaneous rib fracture. Evaluation of IMT should include measures of PImax, dyspnea, health-related quality of life, and exercise capacity.
Publisher: Oxford University Press (OUP)
Date: 06-2019
DOI: 10.1373/CLINCHEM.2018.300335
Abstract: Associations between dairy intake and body composition and cardiometabolic traits have been inconsistently observed in epidemiological studies, and the causal relationship remains ill-defined. We performed Mendelian randomization analysis using an established genetic variant located upstream of the lactase gene (LCT-13910 C/T, rs4988235) associated with dairy intake as an instrumental variable (IV). The causal effects of dairy intake on body composition and cardiometabolic traits (lipids, glycemic traits, and inflammatory factors) were quantified by IV estimators among 182041 participants from 18 studies. Each 1 serving/day higher dairy intake was associated with higher lean mass [β (SE) = 0.117 kg (0.035) P = 0.001], higher hemoglobin A1c [0.009% (0.002) P & 0.001], lower LDL [−0.014 mmol/L (0.006) P = 0.013], total cholesterol (TC) [−0.012 mmol/L (0.005) P = 0.023], and non-HDL [−0.012 mmol/L (0.005) P = 0.028]. The LCT-13910 C/T CT + TT genotype was associated with 0.214 more dairy servings/day (SE = 0.047 P & 0.001), 0.284 cm higher waist circumference (SE = 0.118 P = 0.017), 0.112 kg higher lean mass (SE = 0.027 P = 3.8 × 10−5), 0.032 mmol/L lower LDL (SE = 0.009 P = 0.001), and 0.032 mmol/L lower TC (SE = 0.010 P = 0.001). Genetically higher dairy intake was associated with increased lean mass [0.523 kg per serving/day (0.170) P = 0.002] after correction for multiple testing (0.05/18). However, we find that genetically higher dairy intake was not associated with lipids and glycemic traits. The present study provides evidence to support a potential causal effect of higher dairy intake on increased lean mass among adults. Our findings suggest that the observational associations of dairy intake with lipids and glycemic traits may be the result of confounding.
Publisher: Korean Sleep Society
Date: 31-08-2023
DOI: 10.13078/JSM.230014
Publisher: Springer Science and Business Media LLC
Date: 19-01-2015
DOI: 10.1111/SBR.12103
Publisher: SAGE Publications
Date: 10-2005
Publisher: American Diabetes Association
Date: 10-2004
Publisher: Elsevier BV
Date: 06-2007
Publisher: Wiley
Date: 26-06-2012
DOI: 10.1111/J.1440-1843.2012.02175.X
Abstract: This review article summarizes the content of a series of interrelated workshop presentations from the Annual Scientific Meeting of the Asian Pacific Society of Respirology held in Shanghai in November, 2011. The article describes tips and strategies for writing research papers and research grant applications and includes discussion of: the role of pulmonologists in research the debates around the use of the journal impact factor tips for writing manuscripts and publishing research in high-impact journals how journals assess manuscripts and the most common reasons editors reject manuscripts how to write grant applications and what grant panels look for in successful proposals and how to undertake research in resource-limited countries.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2018
Publisher: Elsevier BV
Date: 07-2020
Publisher: Oxford University Press (OUP)
Date: 11-2011
DOI: 10.5665/SLEEP.1380
Publisher: Informa UK Limited
Date: 16-10-2018
DOI: 10.1080/02640414.2018.1531499
Abstract: The present study aimed to investigate pre-sleep behaviours (including evening electronic device use) and sleep quantity in well-trained athletes. Seventy well-trained athletes (44 females, 26 males) aged 21 ± 4 y from a range of team and in idual sports were asked to complete an online sleep diary for 7 days. The sleep diary included questions about pre-sleep behaviours (e.g. napping, caffeine intake), electronic device use in the 2 h prior to bedtime (e.g. type of device and duration of use) and sleep (e.g. time in bed, sleep onset latency). On average, athletes spent 8:20 ± 1:21 h in bed each night. Associations between age, time in bed and sleepiness suggested that younger athletes spent more time in bed (B = -0.05, p = 0.001) but felt sleepier (r = -0.32, p < 0.01) than older athletes. On average, athletes mostly used electronic devices for 0-30 min prior to sleep. The use of multiple devices in the evening was associated with more perceived difficulty in falling asleep (B = 0.22, p = 0.03), but no associations existed with other sleep variables. In summary, younger athletes may require later start times or improved sleep quality to resolve excessive sleepiness.
Publisher: Wiley
Date: 03-03-2023
DOI: 10.1111/APA.16719
Abstract: Investigate if childhood measures of sleep health are associated with epigenetic age acceleration in late adolescence. Parent‐reported sleep trajectories from age 5 to 17, self‐reported sleep problems at age 17, and six measures of epigenetic age acceleration at age 17 were studied in 1192 young Australians from the Raine Study Gen2. There was no evidence for a relationship between the parent‐reported sleep trajectories and epigenetic age acceleration ( p ≥ 0.17). There was a positive cross‐sectional relationship between self‐reported sleep problem score and intrinsic epigenetic age acceleration at age 17 ( b = 0.14, p = 0.04), which was attenuated after controlling for depressive symptom score at the same age ( b = 0.08, p = 0.34). Follow‐up analyses suggested this finding may represent greater overtiredness and intrinsic epigenetic age acceleration in adolescents with higher depressive symptoms. There was no evidence for a relationship between self‐ or parent‐reported sleep health and epigenetic age acceleration in late adolescence after adjusting for depressive symptoms. Mental health should be considered as a potential confounding variable in future research on sleep and epigenetic age acceleration, particularly if subjective measures of sleep are used.
Publisher: American Physiological Society
Date: 08-2000
DOI: 10.1152/JAPPL.2000.89.2.537
Abstract: The increase in systemic blood pressure after an obstructive apnea is due, in part, to sympathetically mediated vasoconstriction. We questioned whether upper airway (UA) receptors could contribute reflexly to this vasoconstriction. Four unanesthetized dogs were studied during wakefulness and non-rapid-eye-movement (NREM) sleep. The dogs breathed via a fenestrated tracheostomy tube sealed around the tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration was closed and exposing the UA to negative inspiratory intrathoracic pressure when it was open. The blood pressure response to three UA perturbations was studied: 1) square-wave negative pressures sufficient to cause UA collapse with the fenestration closed during a mechanical hyperventilation-induced central apnea 2) tracheal occlusion with the fenestration open vs. closed and 3) high-frequency pressure oscillations (HFPO) with the fenestration closed. During NREM sleep, 1) blood pressure response to tracheal occlusion was similar with the fenestration open or closed 2) collapsing the UA with negative pressures failed to alter blood pressure during a central apnea and 3) application of HFPO to the UA during eupnea and resistive-loaded breaths increased heart rate and blood pressure. However, these changes were likely to be secondary to the effects of HFPO-induced reflex changes on prolonging expiratory time. These findings suggest that activation of UA pressure-sensitive receptors does not contribute directly to the pressor response associated with sleep-disordered breathing events.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Oxford University Press (OUP)
Date: 07-01-2017
DOI: 10.1093/IJE/DYW308
Publisher: Termedia Sp. z.o.o.
Date: 06-2019
Abstract: Sleep is a vital component of preparation, performance and recovery for a Super Rugby game. The purpose of this study was to quantify sleep behaviours and alertness of professional rugby union players during training and a game. Thirty-six rugby union players from a Super Rugby team wore a wrist-activity device (Readiband™) to measure sleep for 3 days before, 3 days after and on the night of an evening game. Players were separated into those selected to play the game (n = 23) and those who were not (n = 13). Alertness was assessed for all training and game times using bio-mathematical modelling. Alertness measures ≤90% were considered to reflect impaired reaction time. Those selected to play in the game progressively increased sleep duration over the nights prior to the game (by 92 min p ≤ 0.05) by delaying wake time. Players went to bed later after the game (02:20 ± 114 min vs 22:57 ± 60 min p ≤ 0.001) which resulted in decreased sleep duration on game night compared to pre-game nights (296 ± 179 min vs 459 ± 78 min p ≤ 0.05). Four players did not achieve any sleep on game night. Sleep duration appeared to be truncated by early morning training sessions (before 08:00) on the second and third mornings after the game. Alertness was % for all training and game times for all players. In conclusion, in the days leading into a Super Rugby game, players delay morning time at wake and consequently increase sleep duration with post-game sleep reduced in some.
Publisher: Wiley
Date: 05-08-2023
DOI: 10.1111/GEC3.12723
Abstract: As calls grow for relational approaches to nature and wellbeing research that consider reciprocity in human‐environment interactions, the concept of affordances is gaining importance as a useful way of thinking about nature experiences. Affordances provide a framework to enable in idualised conceptions of nature by focusing on what is functionally meaningful to people. However, affordance thinking is currently limited in its ability to help us understand how peoples' background, culture and circumstances shape interactions with nature ‐ a critical issue with respect to inclusivity and the under‐representation of some sections of society. Bourdieu's theory of practice is a well‐established set of ‘thinking tools’ which potentially help addresses these influences. It examines how our social environment may pattern our practices, attitudes, and perceptions. In this paper, we review the various applications of affordances before providing an overview of how Bourdieu's concepts of habitus , capital and field can complement, and be integrated with, affordance thinking for novel applications to greenspace research. Bridging these areas of thinking will facilitate development of a more intersectional and complete understanding of nature experiences, including the quality and inclusivity of green and natural spaces.
Publisher: American Physiological Society
Date: 05-2000
DOI: 10.1152/JAPPL.2000.88.5.1840
Abstract: Our study was concerned with the effect of brain hypoxia on cardiorespiratory control in the sleeping dog. Eleven unanesthetized dogs were studied seven were prepared for vascular isolation and extracorporeal perfusion of the carotid body to assess the effects of systemic [and, therefore, central nervous system (CNS)] hypoxia (arterial [Formula: see text] = 52, 45, and 38 Torr) in the presence of a normocapnic, normoxic, and normohydric carotid body during non-rapid eye movement sleep. A lack of ventilatory response to systemic boluses of sodium cyanide during carotid body perfusion demonstrated isolation of the perfused carotid body and lack of other significant peripheral chemosensitivity. Four additional dogs were carotid body denervated and exposed to whole body hypoxia for comparison. In the sleeping dog with an intact and perfused carotid body exposed to specific CNS hypoxia, we found the following. 1) CNS hypoxia for 5–25 min resulted in modest but significant hyperventilation and hypocapnia (minute ventilation increased 29 ± 7% at arterial [Formula: see text] = 38 Torr) carotid body-denervated dogs showed no ventilatory response to hypoxia. 2) The hyperventilation was caused by increased breathing frequency. 3) The hyperventilatory response developed rapidly ( s). 4) Most dogs maintained hyperventilation for up to 25 min of hypoxic exposure. 5) There were no significant changes in blood pressure or heart rate. We conclude that specific CNS hypoxia, in the presence of an intact carotid body maintained normoxic and normocapnic, does not depress and usually stimulates breathing during non-rapid eye movement sleep. The rapidity of the response suggests a chemoreflex meditated by hypoxia-sensitive respiratory-related neurons in the CNS.
Publisher: Springer Science and Business Media LLC
Date: 24-07-2023
Publisher: Wiley
Date: 04-11-2023
DOI: 10.1111/JSR.13778
Abstract: Chronotype is linked to adverse health measures and may have important associations with obstructive sleep apnea and blood pressure, but data are limited. This study aimed to determine the separate and combined associations of chronotype with obstructive sleep apnea and blood pressure in a middle‐aged community population. Adults ( n = 811) from the Raine Study (female = 59.2% age mean [range] = 56.6 [42.1–76.6] years) were assessed for chronotype (Morningness–Eveningness Questionnaire), blood pressure and hypertension (doctor diagnosed or systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg), and obstructive sleep apnea at different in‐laboratory apnea–hypopnea index thresholds (5, 10, 15 events per hr). Linear and logistic regression models examined relationships between chronotype and the presence and severity of obstructive sleep apnea, blood pressure, hypertension, and blood pressure stratified by obstructive sleep apnea severity at above‐mentioned apnea–hypopnea index thresholds. Covariates included age, sex, body mass index, alcohol consumption, smoking, physical activity, sleep duration, anti‐hypertensive medication, insomnia, and depressive symptoms. Most participants were categorised as morning (40%) or intermediate (43%), with 17% meeting criteria for evening chronotypes. Participants with apnea–hypopnea index ≥ 15 events per hr and morning chronotype had higher systolic (9.9 mmHg, p 0.001) and a trend for higher diastolic blood pressure (3.4 mmHg, p = 0.07) compared with those with an evening chronotype, and higher systolic blood pressure compared with those with an intermediate chronotype (4.8 mmHg, p = 0.03). Across chronotype categories, no differences in systolic or diastolic blood pressure or odds of hypertension were found at apnea–hypopnea index thresholds of ≥ 5 or ≥ 10 events per hr. Among participants with apnea–hypopnea index ≥ 15 events per hr, systolic blood pressure is higher in those with a morning chronotype than evening and intermediate chronotypes. Assessment for morning chronotype may improve risk stratification for hypertension in patients with obstructive sleep apnea.
Publisher: American Thoracic Society
Date: 05-2010
DOI: 10.1164/AJRCCM-CONFERENCE.2010.181.1_MEETINGABSTRACTS.A6767
Publisher: Oxford University Press (OUP)
Date: 10-2023
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/BT11176
Abstract: The pollen morphology of 36 genera and 147 species from the Myrtaceae tribes Chamelaucieae, Leptospermeae and Lindsayomyrteae was surveyed using scanning electron microscopy (SEM) and light microscopy (LM). Syncolpate pollen were observed in all genera of Leptospermeae and some genera of Chamelaucieae. Genera of tribe Chamelaucieae displayed five distinct colpal morphologies, which makes it the tribe with the most erse pollen in Myrtaceae. Six genera of Chamelaucieae, including Actinodium, Chamelaucium, Darwinia, Homoranthus, Pileanthus and Verticordia, produce large acolpate pollen not observed in any other Myrtaceae. Two of these genera produce distinct pollen Actinodium is the only genus to have prolate-spheroidal shaped pollen, and Pileanthus pollen is large and dicolporate. A number of anomalous aperture types occurred in species of Chamelaucieae, including monocolporate (Homoranthus thomasii), pentacolporate (Calytrix oldfieldii) and hexacolporate (Sannantha tozerensis). Pollen of Lindsayomyrteae appeared similar to those of Leptospermeae and Chamelaucieae, and on the basis of pollen features, could be related to these two tribes.
Publisher: Oxford University Press (OUP)
Date: 13-04-2020
Abstract: Sleep disorders in adults are associated with adverse health effects including reduced quality of life and increased mortality. However, there is little information on sleep disorders in young adults. A cross-sectional observational study was undertaken in 1,227 young adults participating in the Western Australian Pregnancy (Raine) Study (2012–2014) to describe the prevalence of common sleep disorders. In-laboratory polysomnography (PSG) and validated survey methods were used, including the Epworth Sleepiness Scale, Pittsburgh Sleep Symptom Questionnaire-Insomnia, and International Restless Legs Syndrome Study Group criteria. A total of 1,146 participants completed a core questionnaire, 1,051 completed a sleep-focused questionnaire and 935 had analyzable PSG data. Participants had a mean age of 22.2 years and female to male ratio of 1.1 to 1. The respective sleep disorder prevalences in females and males were: obstructive sleep apnea (OSA) (apnea-hypopnea index [AHI]: ≥5 events/hour) 14.9% (95% CI: 11.8–18.5) and 26.9% (95% CI: 22.9–31.2) chronic insomnia, 19.3% (95% CI: 16.7–23.9) and 10.6% (95% CI: 8.3–13.9) restless legs syndrome, 3.8% (95% CI: 2.4–5.6) and 1.9% (95% CI: 0.9–3.4) and abnormal periodic leg movements during sleep (& movements/hour), 8.6% (95% CI: 6.3–11.5) and 9.6% (95% CI: 7.1–12.7). There were statistically significant differences in prevalence between sexes for OSA and insomnia, which persisted after adjustment for body mass index and education. In those with complete data on all sleep-related assessments (n = 836), at least one sleep disorder was present in 41.0% of females and 42.3% of males. Sleep disorders are very common in young adults. Health practitioners should be aware of these high prevalences, as early identification and treatment can improve quality of life and may reduce later morbidity and mortality.
Publisher: BMJ
Date: 05-2019
DOI: 10.1136/BMJOPEN-2018-026276
Abstract: The purpose of the Raine Study is to improve human health and well-being by studying the life-course of a cohort of Western Australians, based on a life-course conceptual framework that considers interactions between genetics, phenotypes, behaviours, the environment and developmental and social outcomes. Between May 1989 and November 1991, 2900 pregnant women were enrolled in the Raine Study in Perth, Western Australia. In total, 2730 women gave birth to 2868 children (Generation 2) between August 1989 and April 1992. The mothers and fathers of Generation 2 are referred to as Generation 1 of the Raine Study. In the most recent Generation 1 follow-up, 636 mothers and 462 fathers participated. Until the 26-year follow-up of Generation 1 the focus of research within the Raine Study was on outcomes in Generation 2, with information on the parents mainly being used to examine its influence on their children’s outcomes. For ex le, recent findings showed that several characteristics of mothers, such as obesity, early mid-gestational weight gain and socioeconomic status were associated with non-alcoholic fatty liver disease, adiposity and cardiometabolic characteristics in offspring. Other findings showed that parents with back pain were more likely to have offspring who experienced back pain. Also, non-linear and dynamic relationships were found between maternal working hours and offspring overweight or obesity. The Raine Study will continue to provide access to its dense longitudinal genetic, phenotypic, behavioural, environmental, developmental and social data to undertake studies with the ultimate goal of improving human health and well-being. Analyses of data from the recent Generation 1 year 26 follow-up are underway. ACTRN12617001599369
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/S0004-9514(14)60155-0
Abstract: Chronic obstructive pulmonary disease (COPD) is a progressive, common and costly condition. Dyspnoea frequently limits activity and reduces health-related quality of life. In addition to impaired lung function, peripheral muscle deconditioning and respiratory muscle dysfunction also contribute to dyspnoea and reduced exercise capacity. Pulmonary rehabilitation using whole body exercise training improves peripheral muscle function and reduces dyspnoea but does not improve respiratory muscle function. Providing that adequate training intensities are utilised, specific loading of the inspiratory muscles with commercially available hand-held devices can improve inspiratory muscle strength and endurance. Several studies have investigated the effects of inspiratory muscle training on dyspnoea in COPD subjects. Results of these studies are conflicting, most likely reflecting methodological shortcomings including insufficient training load, insensitive outcome measures, and inadequate statistical power. This paper describes the origin of dyspnoea in COPD, with particular attention given to the role of inspiratory muscle dysfunction in its genesis and its possible amelioration through inspiratory muscle training.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.OPHTHA.2019.04.041
Abstract: Obstructive sleep apnea (OSA) is linked to increased glaucoma risk in middle-aged and older adults. However, little is known about associations between OSA and glaucoma-related optic disc parameters in young adults. We explored associations between overnight polysomnography-derived measures of OSA and the optic disc in young adults. Cross-sectional cohort study. Eight hundred forty-eight adults 19 to 22 years of age. Participants underwent an ophthalmic examination that included OCT imaging of the optic disc and measurements of intraocular pressure, axial length, and refractive error. Participants then underwent an overnight polysomnography study that obtained measurements of apnea-hypopnea index (AHI), peripheral oxygen saturation level, and number of cortical arousals from sleep. Based on the AHI results, participants were grouped into no OSA (AHI < 5 events/hour), mild OSA (AHI ≥ 5 and <15 events/hour), moderate OSA (AHI ≥ 15 and <30 events/hour), or severe OSA (AHI ≥ 30 events/hour). Neuroretinal rim area, horizontal and vertical widths, and peripapillary retinal nerve fiber layer (RNFL) thickness. The median AHI result across the study cohort was 2.2 events per hour (interquartile range, 1.0-4.4 events/hour). Based on the AHI results, 178 participants (21.0%) demonstrated OSA: 150 with mild OSA, 26 with moderate OSA, and 2 with severe OSA. In the unadjusted analyses, participants with OSA on average showed thinner peripapillary RNFL at the inferotemporal (P = 0.026) and superotemporal (P = 0.008) segments compared with those without OSA. Additionally, higher AHI results were associated with thinner RNFL superotemporally (P = 0.007). These findings remained significant after adjusting for gender, body mass index, ethnicity, and potential ocular confounders. There were no significant differences in optic disc measures between groups of OSA severity. Obstructive sleep apnea may be associated with preclinical thinning of the peripapillary RNFL in young adults. This suggests that an increased glaucoma risk already may be present in in iduals with OSA since young adulthood. Long-term follow-up of this cohort will allow further optic disc changes in relationship to polysomnography parameters to be documented and associations with future glaucoma diagnosis to be explored.
Publisher: Wiley
Date: 22-10-2010
DOI: 10.1111/J.1445-5994.2009.02113.X
Abstract: Lung cancer is the most common cause of cancer death in Australia, Europe and the USA. Up to 20-30% of these cancers eventually affect the central airways and result in reduced quality of life, dyspnoea, haemoptysis, post-obstructive pneumonia and ultimately death. Non-malignant processes may also lead to central airway obstruction and can have similar symptoms. With the development of newer technologies, the last 20 years have seen the emergence of the field of interventional pulmonology to deal specifically with the diagnosis and management of thoracic malignancy, including obstruction of the central airways. This review discusses the pathology, pre-procedure work-up and management options for obstructing central airway lesions. Several treatment modalities exist for dealing with endobronchial pathology with local availability and expertise guiding choice of treatment. While the literature lacks large, multicentre, randomized studies defining the optimal management strategy for a given problem, there is growing evidence from numerous case studies of improved physiology, of quality of life and possibly of survival with modern interventional techniques.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-10-2015
DOI: 10.5664/JCSM.5078
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2005
DOI: 10.1249/01.MSS.0000175051.47170.33
Abstract: Gastroesophageal reflux is commonly reported during high-intensity endurance exercise in otherwise healthy asymptomatic in iduals. Although the mechanisms underlying this exercise-induced reflux are unknown, it most likely reflects a failure of the primary barrier to reflux, the lower esophageal sphincter (LES). The aim of this study was to determine the influence of exercise with and without ingestion of fluid on the LES barrier pressure in asymptomatic in iduals. Seven recreational cyclists (five males) performed four 5-min bouts of cycle exercise at 90% VO2max, each separated by 1-3 min. Before, during, and after exercise, measurements were made of esophageal pressure (Pes), LES pressure (Ples), and gastric pressure (Pg). LES barrier pressure (Pb) was defined as the difference between Ples and Pg. Following exercise bouts 2 and 3, subjects ingested 600 and 200 mL of a sports drink, respectively. Pb before exercise was 13.1 +/- 5.2 cm H2O (+/- SD), decreased to 6.5 +/- 4.6 cm H2O during each of the four bouts of high-intensity exercise (P < 0.05), and remained decreased at 7.4 +/- 3.5 cm H2O after exercise (P < 0.05). High-intensity exercise reduces LES Pb during exercise in asymptomatic in iduals. The magnitude of this exercise-induced impairment in LES function is unaffected by ingestion of a sports drink.
Publisher: SPIE
Date: 14-04-2008
DOI: 10.1117/12.786827
Publisher: Wiley
Date: 28-04-2010
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2021
DOI: 10.1519/JSC.0000000000002991
Abstract: Jones, MJ, Dawson, B, Eastwood, PR, Halson, SL, Miller, J, Murray, K, Dunican, IC, Landers, GJ, and Peeling, P. Influence of electronic devices on sleep and cognitive performance during athlete training c s. J Strength Cond Res 35(6): 1620–1627, 2021—This study investigated the effects of removing athletes' electronic devices in the evening on sleep and performance during training c s. Water polo athletes ( n = 26) attending a 7-night training c (study 1) and triathletes ( n = 23) attending a 4-night training c (study 2) were randomly allocated to a no-device group (no electronic devices could be used after dinner or overnight ND) or control group (unrestricted electronic device use CON). Sleep was monitored through wrist actigraphy. The ND group completed a questionnaire measuring anxiety related to being unable to use electronic devices (“nomophobia”). Triathletes also completed a psychomotor vigilance test (PVT) at the start and end of c . Water polo ND athletes went to bed earlier and spent longer time in bed than CON on the first night, but not on other nights. In triathletes, sleep quantity was not different between groups on any night. No statistically significant differences were observed for changes in nomophobia from the first to the last night of c . No differences in PVT performance were observed between ND and CON triathletes. In conclusion, removal of evening electronic devices does not improve sleep quantity or cognitive performance in athletes during short-duration (4–7 nights) training c s.
Publisher: Elsevier
Date: 2017
Publisher: Wiley
Date: 22-10-2022
DOI: 10.1111/OPO.12905
Abstract: Cross‐sectional studies have variably reported that poor sleep quality may be associated with myopia in children. Longitudinal data, collected over the ages when myopia develops and progresses, could provide new insights into the sleep‐myopia paradigm. This study tested the hypothesis that 12‐year trajectories of sleep behaviour from childhood to adolescence is associated with myopia during young adulthood. At the 5‐, 8‐, 10‐, 14‐ and 17‐year follow‐ups of the longitudinal Raine Study, which has been following a cohort since their birth in 1989–1992, participants' parents/guardians completed the Child Behaviour Checklist questionnaire (CBCL), which collected information on their child's sleep behaviour and quality. The CBCL includes six questions measuring sleep behaviour, which parents rated as 0 = not true, 1 = somewhat/sometimes true, or 2 = very/often true. Scores were summed at each follow‐up to form a composite “sleep behaviour score”. Latent Class Growth Analysis (LCGA) was used to classify participants according to their 12‐year trajectory of sleep behaviour. At the 20‐year follow‐up, an eye examination was performed which included cycloplegic autorefraction and axial length measurement. The LCGA identified three clusters of participants based on their trajectory of sleep behaviour: those with minimal' (43.6% of the total Raine Study s le), ‘declining’ (48.9%), or ‘persistent’ (7.5%) sleep problems. A total of 1194 participants had ophthalmic data and longitudinal sleep data available for analysis (47.2% female, 85.6% Caucasian). No significant differences were observed in regards to age, sex, ethnicity or ocular parameters between trajectory groups. Unadjusted and fully adjusted analyses demonstrated that sleep problem behaviour was not significantly associated with changes in refractive error, axial length or corneal radius. Our findings do not support the hypothesis that there is an association between sleep behaviour and myopia. Future longitudinal studies should explore sleep trajectory data pre‐ and post‐myopia diagnosis to confirm our results.
Publisher: Springer Science and Business Media LLC
Date: 16-11-2013
DOI: 10.1007/S11325-012-0785-0
Abstract: Undiagnosed obstructive sleep apnoea (OSA) in the community makes comparisons of OSA subjects with control s les from the general population problematic. This study aims to estimate undiagnosed moderate to severe OSA in a general population s le and to determine the capacity of questions from the Berlin questionnaire (BQ) to identify subjects without diagnosed OSA of this severity. Using a general population s le (n = 793) with no history of OSA, case and control status for moderate-severe OSA was determined by home-based nasal flow and oximetry-derived apnoea-hypopnoea index using a cut-off value of ≥ 15 events/h to define cases. The diagnostic accuracy of the complete BQ and its component questions in identifying cases was assessed by calculating sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios and post-test probabilities. The age-standardised prevalence estimate of moderate-severe OSA was 9.1 % (12.4 % in men, 5.7 % in women). Sensitivity of the BQ in this population was 54 %, and specificity, 70 %. A combination of questions regarding snoring frequency and hypertension provided maximal post-test probability of OSA and greatest post-screen s le size. Undiagnosed OSA is highly prevalent in the Western Australian general population. While the complete BQ is a sub-optimal screening instrument for the general population, snoring frequency or hypertension can be used to screen out moderate-severe OSA from general population s les with limited reduction in s le size. As there are few general population s les available for epidemiological or genetic studies of OSA and its associated phenotypes, these results may usefully inform future case-control studies.
Publisher: SPIE
Date: 08-2006
DOI: 10.1117/12.696987
Publisher: Springer Science and Business Media LLC
Date: 28-09-2022
DOI: 10.1038/S41598-022-20308-2
Abstract: Mental health conditions confer considerable global disease burden in young adults, who are also the highest demographic to work shifts, and of whom 20% meet criteria for a sleep disorder. We aimed to establish the relationship between the combined effect of shift work and sleep disorders, and mental health. The Raine Study is the only longitudinal, population-based birth cohort in the world with gold-standard, Level 1 measurement of sleep (polysomnography, PSG) collected in early adulthood. Participants (aged 22y) underwent in-laboratory PSG and completed detailed sleep questionnaires. Multivariable adjusted robust linear regression models were conducted to explore associations with anxiety (GAD7) and depression (PHQ9), adjusted for sex, health comorbidities, and work hours/week. Data were from 660 employed young adults (27.3% shift workers). At least one clinically significant sleep disorder was present in 18% of shift workers (day, evening and night shifts) and 21% of non-shift workers ( p = 0.51) 80% were undiagnosed. Scores for anxiety and depression were not different between shift and non-shift workers ( p = 0.29 and p = 0.82) but were higher in those with a sleep disorder than those without ( Md(IQR) anxiety: 7.0(4.0–10.0) vs 4.0(1.0–6.0)), and depression: (9.0(5.0–13.0) vs 4.0(2.0–6.0)). Considering evening and night shift workers only (i.e. excluding day shift workers) revealed an interaction between shift work and sleep disorder status for anxiety ( p = 0.021), but not depression ( p = 0.96), with anxiety scores being highest in those shift workers with a sleep disorder ( Md(IQR) 8.5(4.0–12.2). We have shown that clinical sleep disorders are common in young workers and are largely undiagnosed. Measures of mental health do not appear be different between shift and non-shift workers. These findings indicate that the identification and treatment of clinical sleep disorders should be prioritised for young workers as these sleep disorders, rather than shift work per se , are associated with poorer mental health. These negative mental health effects appear to be greatest in those who work evening and/or night shift and have a sleep disorder.
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.IJPSYCHO.2022.06.019
Abstract: This study aimed to determine the capacity of baroreflex sensitivity, derived from the Valsalva manoeuvre (BRS_v), to predict state anxiety induced by a biological stressor (CO
Publisher: Elsevier BV
Date: 08-2023
Publisher: Wiley
Date: 24-08-2021
DOI: 10.1111/RESP.14139
Abstract: See related article
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.RMED.2017.10.008
Abstract: This study explored the effects of ground-based walking training on physical activity (PA) and sedentary time (ST) in people with chronic obstructive pulmonary disease (COPD). Participants were randomised to a walk group (WG) [supervised, ground-based walking training, two or three times per week for 8-10 weeks] or a control group (CG) [usual medical care]. Before and after the intervention period, PA and ST were measured using the SenseWear
Publisher: American Physiological Society
Date: 1994
DOI: 10.1152/JAPPL.1994.76.1.185
Abstract: To examine respiratory muscle recruitment pattern during inspiratory loading and role of fatigue in limiting endurance, we studied seven normal subjects on 17 +/- 6 days during breathing against progressive inspiratory threshold load. Threshold pressure (Pth) was progressively increased 14 +/- 5 cmH2O every 2 min until voluntary cessation (task failure). Subjects could adopt any breathing pattern. Tidal volume (VT), chest wall motion, end-tidal PCO2, and arterial O2 saturation were measured. At moderate loads [50–75% of maximum Pth (Pthmax)], inspiratory time (TI) decreased and VT/TI and expiratory time increased, increasing time for recovery of muscles between inspirations. At high loads ( 75% Pthmax), VT/TI decreased, which, with progressive decrease in end-expiratory lung volume (EELV) throughout, increased potential for inspiratory force development. Progressive hypoxia and hypercapnia occurred at higher work loads. Immediately after task failure all subjects could recover at high loads and still reachieve initial Pthmax on reimposition of progressive loading. Respiratory pressures were measured in subgroup of three subjects: transdiaphragmatic pressure response to 0.1-ms bilateral supramaximal phrenic nerve stimulation at end expiration initially increased with increasing load/decreasing EELV, consistent with increasing mechanical advantage of diaphragm, but decreased at highest loads, suggesting diaphragm fatigue. Full recovery had not occurred at 30 min after task failure. We demonstrated that progressive threshold loading is associated with systematic changes in breathing pattern that act to optimize muscle strength and increase endurance. Task failure occurred when these compensatory mechanisms were maximal. Inspiratory muscles appeared relatively resistant to fatigue, which was late but persistent.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2019
Publisher: Elsevier BV
Date: 06-1995
DOI: 10.1046/J.1432-0436.1995.5850361.X
Abstract: The present work describes a severe-combined immunodeficient murine xenograft model used to investigate human gastrointestinal ontogenesis. Specifically, the study has tested whether carefully selected regions of human fetal gut are able to undergo region-specific morphogenesis and epithelial cytodifferentiation when transplanted subcutaneously into immunodeficient mice. In addition, double-label in situ hybridisation techniques, utilising specific human and mouse DNA probes, have been adopted to characterise host and donor cell types and to investigate the potential developmental roles for non-epithelial cells in the regulation of epithelial differentiation pathways in vivo. Human fetal small and large bowel developed to form a characteristic mucosa 10 weeks after transplantation, which displayed clear region-specific structural and functional gradients. The initial phase of xenograft epithelialisation closely resembled the stratified type of epithelium which is present during early fetal gastrointestinal development. Idiosyncratic epithelial differentiation pathways were recorded during xenograft regeneration, with an absence of Paneth cells and an abundance of enteroendocrine cells when compared with developed xenograft and paediatric intestine. Such differences may, therefore, be important in ensuring rapid and region-specific development in the absence of conventional luminal stimuli and hormonal changes that occur normally during pregnancy. In situ hybridisation demonstrated an exclusively human origin for the intestinal xenograft epithelium and muscularis mucosa and externa. Although the submucosa and lamina propria were comprised of a chimeric mixture, murine cells were rarely seen to contact with the epithelium, which interacted primarily with human myofibroblasts and human intraepithelial lymphocytes. It is proposed that a 'selection' process operates to maintain species-specific cellular interactions, and this mechanism may subsequently play an important role in regulating epithelial cell differentiation, orchestrated in part by juxtaposed non-epithelial cell types.
Publisher: Springer Berlin Heidelberg
Date: 2007
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2015
Publisher: Elsevier BV
Date: 09-2017
Publisher: BMJ
Date: 09-2016
Publisher: Springer Science and Business Media LLC
Date: 15-04-2019
DOI: 10.1007/S00408-019-00216-5
Abstract: This multi-centred, randomised controlled trial explored the effects of adding ongoing feedback to a 12-month unsupervised maintenance walking program, on daily physical activity (PA) in people with chronic obstructive pulmonary disease. Participants were randomised to either an intervention group (IG) or a usual care group (UCG). During the maintenance program, the IG received ongoing feedback (telephone calls, biofeedback provided via pedometer and progressive goal setting) and the UCG received no feedback. The SenseWear® Pro3 Armband was used to measure PA. Of the 86 participants {IG = 42, (mean [SD]: age 70 [7] years FEV
Publisher: Springer Science and Business Media LLC
Date: 19-03-2019
DOI: 10.1007/S11325-018-1653-3
Abstract: To determine the effect of temazepam on assessment of the severity of obstructive sleep apnea (OSA) by polysomnography (PSG). Analysis of diagnostic laboratory-PSG studies was performed in OSA patients who were administered temazepam (10 mg) to facilitate sleep ("temazepam group", n = 73) and in OSA patients (matched for age, gender, body mass index and study date) in whom temazepam was not administered ("control group", n = 73). Sleep- and respiratory-related variables were compared between the groups for the (i) first 3 h of study following temazepam in the temazepam group (when peak blood concentration is expected) or following lights out in the control group, and (ii) entire study duration. Within the first 3 h, no differences in sleep-related variables were observed between the groups. Over the entire study duration, the temazepam group had a reduced total sleep time compared to the control group, likely due to the overnight sleep difficulties that led to its use. Whether measured during the first 3 h of study or over the entire study duration, no significant differences were detected between the groups for any respiratory-related variable, including apnea hypopnea index, arousal index, oxygen desaturation, apnea index, hypopnea index, and event duration. When patients were considered in terms of OSA severity, decreased arousal index was noted in the temazepam group over the entire study duration, but only in those with severe OSA. Oral administration of 10 mg of temazepam during the course of PSG does not systematically affect assessment of the severity of OSA by PSG.
Publisher: Optica Publishing Group
Date: 28-07-2003
DOI: 10.1364/OE.11.001817
Abstract: We describe a long-range optical coherence tomography system for size and shape measurement of large hollow organs in the human body. The system employs a frequency-domain optical delay line of a configuration that enables the combination of high-speed operation with long scan range. We compare the achievable maximum delay of several delay line configurations, and identify the configurations with the greatest delay range. We demonstrate the use of one such long-range delay line in a catheter-based optical coherence tomography system and present profiles of the human upper airway and esophagus in vivo with a radial scan range of 26 millimeters. Such quantitative upper airway profiling should prove valuable in investigating the pathophysiology of airway collapse during sleep (obstructive sleep apnea).
Publisher: Wiley
Date: 28-11-2023
DOI: 10.1111/PAN.14603
Publisher: BMJ
Date: 1994
DOI: 10.1136/THX.49.1.94
Abstract: A new variant of SARS-CoV-2 (Lineage B.1.1.7) was identified in the UK in December 2020 which was associated with higher transmissibility of COVID-19. The AusDiagnostics SARS-CoV-2, Influenza and RSV 8-well assay is used at sixteen UK hospitals and detects part of the ORF8 gene (together with a segment from the ORF1a gene). The objective of this study was to determine if the recently identified mutation in ORF8 (G28048T) in the B.1.1.7. lineage could be used to identify the new variant quickly in clinical cases with PCR positive results. The melt data from SARS-CoV-2 positives from two hospitals (October through December 2020) were reviewed, and distribution over time and location was evaluated. A low melt variant of the ORF8 licon started to appear in s les from Guy's and St. Thomas' NHS Trust, London, at the start of November, and grew as a proportion of the total positives during the subsequent two months. These low melt variants were very rare during the same period at the Northern Care Alliance, Greater Manchester, North West of UK. It was confirmed that these carried the G28048T mutation. The geographic and temporal distribution of the low melt licons makes it very likely that these are lineage B.1.1.7 strains. The melt temperature of this licon could be used to discriminate between the original and new variants in advance of the full sequencing of the isolate. However, the appearance of other mutations in the same licon means that this approach would be of diminishing value over time.
Publisher: OSA
Date: 2006
DOI: 10.1364/OFS.2006.WA7
Publisher: Wiley
Date: 11-2013
DOI: 10.1111/RESP.12195
Publisher: Oxford University Press (OUP)
Date: 10-2023
Publisher: Elsevier BV
Date: 10-2020
Publisher: Informa UK Limited
Date: 03-2006
Publisher: Wiley
Date: 06-2001
DOI: 10.1046/J.1440-1843.2001.00314.X
Abstract: The aim of this study was to determine whether whole-body endurance training is associated with increased respiratory muscle strength and endurance. Respiratory muscle strength (maximum inspiratory pressure (PImax)) and endurance (progressive threshold loading of the inspiratory muscles) were measured in six marathon runners and six sedentary subjects. PImax was similar between the two groups of subjects but the maximum threshold pressure achieved was greater in marathon runners (90 +/- 8 vs 78 +/- 10% of PImax, respectively, mean +/- SD, P < 0.05). During progressive threshold loading, marathon runners breathed with lower frequency, higher tidal volume, and longer inspiratory and expiratory time. At maximum threshold pressure, marathon runners had lower arterial O2 saturation, but perceived effort (Borg scale) was maximal in both groups. Efficiency of the respiratory muscles was similar in both groups being 2.0 +/- 1.7% and 2.3 +/- 1.8% for marathon runners and sedentary subjects, respectively. The apparent increase in respiratory muscle endurance of athletes was a consequence of a difference in the breathing pattern adopted during loaded breathing rather than respiratory muscle strength or efficiency. This implies that sensory rather than respiratory muscle conditioning may be an important mechanism by which whole-body endurance is increased.
Publisher: Wiley
Date: 30-03-2011
Publisher: Oxford University Press (OUP)
Date: 13-07-2022
Abstract: We tested a telemedicine model of care to initiate continuous positive airway pressure (CPAP) for patients with obstructive sleep apnea (OSA) living in remote Western Australia. A prospective study comparing telemedicine for CPAP initiation in a remote population versus standard face-to-face CPAP initiation in a metropolitan population. The primary outcome was average nightly CPAP use in the final week of a CPAP trial. A total of 186 participants were allocated to either telemedicine (n = 56) or standard care (n = 130). The average distance from the study center for the telemedicine group was 979 km (±792 km) compared to 19 km (±14 km) for the standard care group. The CPAP trial duration in the standard care group was less than the telemedicine group (37.6 vs 69.9 days, p & .001). CPAP adherence in the telemedicine group was not inferior to standard care (Standard 4.7 ± 0.2 h, Telemedicine 4.7 ± 0.3 h, p = 0.86). No differences were found between groups in residual apnea-hypopnea index, symptom response, sleep specific quality of life at the end of the trial, and continued CPAP use (3–6 months). Participant satisfaction was high in both groups. Total health care costs of the telemedicine model were less than the standard model of care. An estimated A$4538 per participant in travel costs was saved within the telemedicine group by reducing the need to travel to the sleep center for in-person management. In remote dwelling adults starting CPAP for the treatment of OSA, outcomes using telemedicine were comparable to in-person management in a metropolitan setting,
Publisher: American Thoracic Society
Date: 15-02-2012
Publisher: The Royal Society
Date: 07-10-2015
Abstract: Prenatal testosterone may have a powerful masculinizing effect on postnatal physical characteristics. However, no study has directly tested this hypothesis. Here, we report a 20-year follow-up study that measured testosterone concentrations from the umbilical cord blood of 97 male and 86 female newborns, and procured three-dimensional facial images on these participants in adulthood (range: 21–24 years). Twenty-three Euclidean and geodesic distances were measured from the facial images and an algorithm identified a set of six distances that most effectively distinguished adult males from females. From these distances, a ‘gender score’ was calculated for each face, indicating the degree of masculinity or femininity. Higher cord testosterone levels were associated with masculinized facial features when males and females were analysed together ( n = 183 r = −0.59), as well as when males ( n = 86 r = −0.55) and females ( n = 97 r = −0.48) were examined separately ( p -values 0.001). The relationships remained significant and substantial after adjusting for potentially confounding variables. Adult circulating testosterone concentrations were available for males but showed no statistically significant relationship with gendered facial morphology ( n = 85, r = 0.01, p = 0.93). This study provides the first direct evidence of a link between prenatal testosterone exposure and human facial structure.
Publisher: IOP Publishing
Date: 18-01-2018
Publisher: Wiley
Date: 07-1992
DOI: 10.1111/J.1471-0528.1992.TB13822.X
Abstract: To provide a comprehensive description of the clinical and histopathological features associated with parvovirus B19 infection of the human fetus. All cases of parvovirus B19-related fetal death presenting to the John Radcliffe Hospital, Oxford, over a 16 year period. Diagnosis was confirmed retrospectively by non-isotopic in situ hybridization for parvovirus B19 DNA. The ten cases occurred in two clusters (1979-80 and 1988-89) and presented between 15 and 29 weeks gestation. In at least three cases maternal infection was asymptomatic. Nine fetuses were grossly hydropic at necropsy. Histological features common to all cases included the presence of typical intranuclear inclusions in erythroid precursor cells and evidence of vasculitis within placental villi. Inflammatory changes were also present in the myocardium of four cases, with evidence of subendocardial fibroelastosis in three. Histological features of fetal parvovirus B19 infection are similar across a range of gestational ages. The heart failure and hydropic state associated with fetal parvovirus infection may be of multifactorial aetiology, and not due to fetal anaemia alone.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-04-2020
DOI: 10.5664/JCSM.8246
Publisher: American Physiological Society
Date: 10-2010
Publisher: Elsevier
Date: 2013
Publisher: Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc.
Date: 12-12-2011
Publisher: Elsevier BV
Date: 2003
Abstract: Specific respiratory muscle training can improve respiratory muscle function in patients with COPD, but the magnitude of improvement appears dependent on the magnitude of the training load. High training loads are difficult to achieve using conventional, constant loading techniques, but may be possible using interval-based training techniques. To assess the feasibility of high-intensity respiratory muscle training, nine subjects with moderate-to-severe COPD (FEV(1) 34 +/- 12% predicted [mean +/- SD]) completed 8 weeks of interval-based respiratory muscle training combined with a general exercise program. This involved three 20-min sessions per week, each session comprising seven 2-min bouts of breathing against a constant inspiratory threshold load, each bout separated by 1 min of unloaded recovery. Inspiratory load was progressively incremented. Respiratory muscle strength (maximum inspiratory pressure generated against an occluded airway [PImax]) and endurance (maximum pressure generated against a progressively increasing inspiratory threshold load [Pthmax]) were measured before and immediately after the 8-week training period. By the third training session (week 1), subjects breathed against a threshold that required generation of pressures equivalent to 68 +/- 5% of the pretraining PImax. By week 8, this had increased to 95 +/- 12% of the pretraining PImax. On completion of training, PImax had increased by 32 +/- 27% (p < 0.05), Pthmax had increased by 56 +/- 33% (p < 0.05), and Pthmax/PImax had increased by 20 +/- 20% (p < 0.05). This study has demonstrated that high-intensity, interval-based respiratory muscle training is feasible in patients with moderate-to-severe COPD, resulting in significant improvements in respiratory muscle strength and endurance when performed three times a week for 8 weeks.
Publisher: American Physiological Society
Date: 15-06-2016
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.67_12618
Publisher: Elsevier BV
Date: 02-2023
Publisher: Informa UK Limited
Date: 04-10-2013
DOI: 10.1080/17461391.2013.843024
Abstract: This study examined the effect of early evening high-intensity training on the sleep of elite male youth soccer players (n = 12) using wrist actigraphy. High-intensity training (TRAIN) nights were compared with a home environment (HOME) condition, created by averaging sleep variables on the night before and after TRAIN nights. Additionally, after TRAIN athletes alternately used cold water immersion (TRAIN+CWI) or none, to assess whether cold water immersion (CWI) had any impact on sleep quality and quantity. Ratings of perceived exertion, fatigue and recovery were recorded after training. Actigraphy sleep measures were bedtime, wake time, sleep duration, sleep onset latency, sleep efficiency and wake after sleep onset. Self-rated scores of sleepiness at bedtime and wake, plus overall sleep quality were also recorded. Only fatigue ratings were higher in TRAIN compared to TRAIN+CWI at bedtime, there were no other differences in training data. Both TRAIN and TRAIN+CWI conditions had significant later (07:45 ± 1:09 h p < 0.01 and 07:34 ± 1:20 h p = 0.01) wake times than HOME (06:44 ± 0:41 h). The TRAIN condition had a significantly higher (7 ± 2 p < 0.01) rating of sleepiness at bedtime compared to HOME (6 ± 1), but no further differences were found in any of the sleep (actigraphy and self-reported) measures. Across all conditions, time spent asleep was ∼7:30 (±0:52) h:min and sleep efficiency was ∼89% (±6.1). In conclusion, early evening high-intensity training had no impact on subsequent sleep quality and quantity, nor was there any effect on sleep after performing CWI post-training.
Publisher: SPIE
Date: 27-02-2019
DOI: 10.1117/12.2506567
Publisher: Elsevier BV
Date: 12-2004
DOI: 10.1016/J.SMRV.2004.07.002
Abstract: Upper airway obstruction is common during both anaesthesia and sleep, as a result of loss of muscle tone present during wakefulness. Patients with obstructive sleep apnoea (OSA) are vulnerable during anaesthesia and sedation as the effects of loss of wakefulness are compounded by drug-induced depression of muscle activity and of arousal responses, so that they cannot respond to asphyxia. Conversely, those with 'difficult' airways during anaesthesia, either because of problems with maintenance of airway patency without tracheal intubation or because intubation itself is problematic, are at increased risk of OSA. These relationships have clinical importance. On the one hand identification of patients with OSA forewarns the anaesthetist of potential difficulty with airway maintenance intra- and postoperatively, influencing choice of anaesthetic technique and postoperative nursing environment. On the other hand difficulty with airway maintenance during anaesthesia should prompt further investigation for the possibility of OSA.
Publisher: Informa UK Limited
Date: 12-02-2018
DOI: 10.1080/17461391.2018.1433238
Abstract: To examine the relationship between regular game-related caffeine consumption on sleep after an evening Super Rugby game. Twenty elite rugby union players wore a wrist-activity monitor to measure sleep for three days before, three days after and on the night of an evening Super Rugby game (19:00-21:00). Players ingested caffeine as they would normally (i.e. before and sometimes during a game) and saliva s les were collected before (17:00) and after (21:30) the game for caffeine concentration. Compared to the nights leading up to the game, on the night of the game, players went to bed 3 h later (23:08 ± 66 min vs 02:11 ± 114 min p < .001) and had 1:30 hh:mm less sleep (5:54 ± 2:59 vs 8:02 ± 1:24 hh:mm p < .05) and four players did not sleep after the game. Post-game caffeine saliva concentrations were greater than pre-game levels in 17 players (Pre-game 0.40 µg/mL vs Post-game 2.77 µg/mL p < .001). The increase in caffeine saliva concentrations was moderately associated with an increase in sleep latency (p < .05), a decrease in sleep efficiency (p < .05), and a trend for a decrease in sleep duration (p = .06) on game night. Caffeine consumption before a Super Rugby game markedly increases post-game saliva caffeine levels. This may contribute to the observed 3.5 h delay in time at sleep onset and the 1.5 h reduction in sleep duration on the night of the game. This study highlights the need for a strategic approach to the use of caffeine within a Super Rugby team considering the potential effect on post-game sleep.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2009
DOI: 10.1097/ALN.0B013E3181A7EC68
Abstract: Upper airway collapsibility is known to increase under anesthesia. This study assessed how this increase in collapsibility evolves during slow Propofol induction and how it relates to anesthesia-induced changes in upper airway muscle activity and conscious state. Nine healthy volunteers were studied. Anesthesia was induced with Propofol in a step-wise manner (effect-site concentration steps of 0.5 microg x ml(-1) from 0 to 3 microg x ml(-1) and thereafter to 4 microg x ml(-1) and 6 microg x ml(-1) [target-controlled infusion]). Airway patency was maintained with continuous positive airway pressure. Pharyngeal collapsibility was assessed at each concentration by measuring critical pressure. Intramuscular genioglossus electromyogram and anesthetic depth (bispectral index score) were monitored throughout. Loss of consciousness was defined as failure to respond to loud verbal command. Loss of consciousness occurred at varying Propofol effect-site concentrations between 1.5 and 4.0 microg x ml(-1). Initially genioglossus electromyographic activity was sustained with increases in Propofol concentration, increasing in some in iduals. At or approaching loss of consciousness, it decreased, often abruptly, to minimal values with an accompanying increase in critical pressure. In most subjects, bispectral index score decreased alinearly with increasing Propofol concentration with greatest rate of change coinciding with loss of consciousness. Slow stepwise induction of Propofol anesthesia is associated with an alinear increase in upper airway collapsibility. Disproportionate decreases in genioglossus electromyogram activity and increases in pharyngeal critical closing pressure were observed proximate to loss of consciousness, suggesting that particular vulnerability exists after transition from conscious to unconscious sedation. Such changes may have parallels with upper airway behavior at sleep onset.
Publisher: Wiley
Date: 27-08-2021
DOI: 10.1111/JSR.13179
Publisher: Wiley
Date: 02-1992
Abstract: Human parvovirus B19 is a cause of aplastic crises in patients with haemolytic anaemias, prolonged bone marrow failure in the immunosuppressed, and fetal death secondary to non-immune hydrops. The immunohistological detection of parvovirus B19 in formalin-fixed, paraffin-embedded tissues has not previously been reported, and definitive diagnosis of infection in such specimens has relied on the use of specialized DNA hybridization and lification techniques. A new monoclonal antibody to B19 capsid proteins, R92F6, was found to be capable of labelling infected cells in paraffin-embedded tissues from all 19 cases of parvovirus-related fetal hydrops tested, and in bone marrow from a child with congenital immunodeficiency and chronic parvovirus infection. Viral antigen was detected both in cytoplasmic and in nuclear distributions using the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique without preceding proteolytic digestion. The viral epitope recognized appears to be highly conserved, as specimens were obtained over a 13-year period from widely spaced locations in the U.K. Antibody R92F6 should facilitate rapid diagnosis of parvovirus B19 infection in routinely processed and archival specimens.
Publisher: Wiley
Date: 10-2019
DOI: 10.1111/JSR.49_12912
Publisher: Oxford University Press (OUP)
Date: 2023
DOI: 10.1093/SLEEPADVANCES/ZPAD028
Abstract: Comparisons of actigraphy findings between studies are challenging given differences between brand-specific algorithms. This issue may be minimized by using open-source algorithms. However, the accuracy of actigraphy-derived sleep parameters processed in open-source software needs to be assessed against polysomnography (PSG). Middle-aged adults from the Raine Study (n = 835 F 58% Age 56.7 ± 5.6 years) completed one night of in-laboratory PSG and concurrent actigraphy (GT3X+ ActiGraph). Actigraphic measures of total sleep time (TST) were analyzed and processed using the open-source R-package GENEActiv and GENEA data in R (GGIR) with and without a sleep diary and additionally processed using proprietary software, ActiLife, for comparison. Bias and agreement (intraclass correlation coefficient) between actigraphy and PSG were examined. Common PSG and sleep health variables associated with the discrepancy between actigraphy, and PSG TST were examined using linear regression. Actigraphy, assessed in GGIR, with and without a sleep diary overestimated PSG TST by (mean ± SD) 31.0 ± 50.0 and 26.4 ± 69.0 minutes, respectively. This overestimation was greater (46.8 ± 50.4 minutes) when actigraphy was analyzed in ActiLife. Agreement between actigraphy and PSG TST was poor (ICC = 0.27–0.44) across all three methods of actigraphy analysis. Longer sleep onset latency and longer wakefulness after sleep onset were associated with overestimation of PSG TST. Open-source processing of actigraphy in a middle-aged community population, agreed poorly with PSG and, on average, overestimated TST. TST overestimation increased with increasing wakefulness overnight. Processing of actigraphy without a diary in GGIR was comparable to when a sleep diary was used and comparable to actigraphy processed with proprietary algorithms in ActiLife.
Publisher: American Physiological Society
Date: 03-2015
DOI: 10.1152/JAPPLPHYSIOL.00724.2014
Abstract: In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (P tm ), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in P tm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a sustained inflation from a baseline P tm of 5 cmH 2 O to 25 cmH 2 O, or deflation to −5 cmH 2 O, for ∼50 min in each case. In one group of airways, lumen narrowing and stiffening in response to electrical field stimulation (EFS) were assessed from volume and pressure signals using a servo-controlled syringe pump with pressure feedback. In a second group of airways, lumen narrowing and the perimeter of the ASM in situ were determined by anatomical optical coherence tomography. In a third group of airways, active tension was determined under isovolumic conditions. Both inflation and deflation reduced the contractile response to EFS. Sustained P tm change resulted in a further decrease in contractile response, which returned to baseline levels upon return to the baseline P tm . These findings reaffirm the importance of P tm in regulating airway narrowing. However, they do not support a role for ASM length adaptation in situ under physiological levels of ASM lengthening and shortening.
Publisher: European Respiratory Society (ERS)
Date: 06-2006
DOI: 10.1183/09031936.06.00105205
Abstract: The aim of the present study was to investigate the effects of an interval-based high-intensity inspiratory muscle training (H-IMT) programme on inspiratory muscle function, exercise capacity, dyspnoea and health-related quality of life (QoL) in subjects with chronic obstructive pulmonary disease. A double-blind randomised controlled trial was performed. Sixteen subjects (11 males, mean forced expiratory volume in one second (FEV(1)) 37.4+/-12.5%) underwent H-IMT performed at the highest tolerable inspiratory threshold load (increasing to 101% of baseline maximum inspiratory pressure). Seventeen subjects (11 males, mean FEV(1 )36.5+/-11.5%) underwent sham inspiratory muscle training (S-IMT) at 10% of maximum inspiratory pressure. Training took place three times a week for 8 weeks and was fully supervised. Pre- and post-training measurements of lung function, maximum inspiratory pressure, maximum threshold pressure, exercise capacity, dyspnoea and QoL (Chronic Respiratory Disease Questionnaire CRDQ) were obtained. H-IMT increased maximum inspiratory pressure by 29%, maximum threshold pressure by 56%, 6-min walk distance by 27 m, and improved dyspnoea and fatigue (CRDQ) by 1.4 and 0.9 points per item, respectively. These changes were significantly greater than any seen following S-IMT. In conclusion, high-intensity inspiratory muscle training improves inspiratory muscle function in subjects with moderate-to-severe chronic obstructive pulmonary disease, yielding meaningful reductions in dyspnoea and fatigue.
Publisher: Optica Publishing Group
Date: 06-04-2009
DOI: 10.1364/OE.17.006568
Abstract: Anatomical optical coherence tomography (aOCT) is a long-range endoscopic imaging modality capable of quantifying size and shape of the human airway. A challenge to its in vivo application is motion artifact due to respiratory-related movement of the airway walls. This paper represents the first demonstration of respiratory gating of aOCT airway data, and introduces a novel error measure to guide appropriate parameter selection. Results indicate that at least four gates per respiratory cycle should be used, with only minor improvements as the number of gates is further increased. It is shown that respiratory gating can substantially improve the quality of aOCT images and reveal events and features that are otherwise obscured by blurring.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.NEUBIOREV.2016.09.006
Abstract: Huntington's disease (HD) is a fatal neurodegenerative disease caused by an extended polyglutamine tract in the huntingtin protein. Circadian, sleep and hypothalamic-pituitary-adrenal (HPA) axis disturbances are observed in HD as early as 15 years before clinical disease onset. Disturbances in these key processes result in increased cortisol and altered melatonin release which may negatively impact on brain-derived neurotrophic factor (BDNF) expression and contribute to documented neuropathological and clinical disease features. This review describes the normal interactions between neurotrophic factors, the HPA-axis and circadian rhythm, as indicated by levels of BDNF, cortisol and melatonin, and the alterations in these intricately balanced networks in HD. We also discuss the implications of these alterations on the neurobiology of HD and the potential to result in hypothalamic, circadian, and sleep pathologies. Measurable alterations in these pathways provide targets that, if treated early, may reduce degeneration of brain structures. We therefore focus here on the means by which multidisciplinary therapy could be utilised as a non-pharmaceutical approach to restore the balance of these pathways.
Publisher: Elsevier BV
Date: 07-2009
Abstract: Flexible bronchoscopy is a common procedure that is used in both diagnostic and therapeutic settings but does not readily permit measurement of central airway dimensions. Anatomic optical coherence tomography (a OCT), a modification of conventional optical coherence tomography (OCT), is a novel light-based imaging tool with the capacity to measure the diameter and lumen area of the central airways accurately during bronchoscopy. This study describes the first clinical use of aOCT imaging in the lower airways in three in iduals with common endobronchial pathologies. During bronchoscopy, a specialized fiberoptic probe was passed through the biopsy channel of a standard flexible bronchoscope to the site of airway pathology. Airway dimensions were measured from the generated cross-sectional images in three subjects, one with subglottic tracheal stenosis (subject 1), one with malignant left main bronchus (LMB) obstruction (subject 2), and another with severe tracheomalacia (subject 3). Measured dimensions included internal airway diameter, cross-sectional area, and, in subject 1, stenosis length. Tracheal stenosis dimensions, measured using aOCT imaging, correlated with chest CT scan findings and guided the choice of airway stent (subject 1). The airway beyond a malignant obstruction of the LMB, and beyond bronchoscopic view, could be imaged using aOCT, and the distal extent of obstructing tumor identified (subject 2). The severity of newly diagnosed tracheomalacia was able to be quantified using aOCT imaging (subject 3). aOCT imaging during bronchoscopy allows accurate real-time airway measurements and may assist bronchoscopic assessment.
Publisher: BMJ
Date: 16-03-2017
DOI: 10.1136/BMJ.J1000
Publisher: Wiley
Date: 15-04-2008
DOI: 10.1111/J.1365-2869.2008.00647.X
Abstract: This study compared shape, size and length of the pharyngeal airway in in iduals with and without obstructive sleep apnoea (OSA) using a novel endoscopic imaging technique, anatomical optical coherence tomography (aOCT). The study population comprised a preliminary study group of 20 OSA patients and a subsequent controlled study group of 10 OSA patients and 10 body mass index (BMI)-, gender- and age-matched control subjects without OSA. All subjects were scanned using aOCT while awake, supine and breathing quietly. Measurements of airway cross-sectional area (CSA) and anteroposterior (A-P) and lateral diameters were obtained from the hypo-, oro- and velopharyngeal regions. A-P : lateral diameter ratios were calculated to provide an index of regional airway shape. In all subjects, pharyngeal CSA was lowest in the velopharynx. Patients with OSA had a smaller velopharyngeal CSA than controls (maximum CSA 91 +/- 40 versus 153 +/- 84 mm(2) P < 0.05) but comparable oro- (318 +/- 80 versus 279 +/- 129 mm(2) P = 0.48) and hypopharyngeal CSA (250 +/- 105 versus 303 +/- 112 mm(2) P = 0.36). In each pharyngeal region, the long axis of the airway was oriented in the lateral diameter. Airway shape was not different between the groups. Pharyngeal airway length was similar in both groups, although the OSA group had longer uvulae than the control group (16.8 +/- 6.2 versus 11.2 +/- 5.2 mm P < 0.05). This study has shown that in iduals with OSA have a smaller velopharyngeal CSA than BMI-, gender- and age-matched control volunteers, but comparable shape: a laterally oriented ellipse. These findings suggest that it is an abnormality in size rather than shape that is the more important anatomical predictor of OSA.
Publisher: Springer Science and Business Media LLC
Date: 21-03-2013
DOI: 10.1007/S11325-013-0828-1
Abstract: Obstructive sleep apnoea (OSA) is a common disorder, for which continuous positive airway pressure (CPAP) therapy is a standard treatment. Despite its well-established efficacy, many patients choose not to initiate CPAP treatment. The present study investigated the degree to which biological measures (e.g. Apnoea-Hypopnoea Index [AHI]), symptom experiences (e.g. fatigue) and illness representations (e.g. perceived consequences) predict the decision of in iduals newly diagnosed with OSA to undergo a trial of CPAP therapy. Four hundred forty-nine in iduals (316 males) newly diagnosed with OSA. Epworth sleepiness scale (ESS), Fatigue Severity Scale, Depression Anxiety Stress Scale and Illness Perception Questionnaire-Revised (IPQ-R) were administered at time of sleep study. These, patient demographics and sleep study variables were used to determine factors predicting patient decision to proceed with a trial of CPAP. The participants were most likely to attribute their OSA to unchangeable and psychological factors. For those with moderate OSA (AHI, 15 to 30) IPQ-R illness consequence was predictive of decision to initiate CPAP (p = 0.002). For severe OSA (AHI >30) age, ESS and IPQ illness causal beliefs were predictive of decision to initiate CPAP (p < 0.001). Illness beliefs are important determinants of the choice of recently diagnosed OSA patients whether or not to undertake a trial of CPAP therapy. Concerns about illness consequences were important in those with moderate OSA. In severe OSA, sleepiness symptoms are more prominent and a more significant determinant of CPAP uptake along with age and causal beliefs.
Publisher: Oxford University Press (OUP)
Date: 10-2008
Publisher: Wiley
Date: 11-08-2015
DOI: 10.1111/JSR.12193
Abstract: Catheters that traverse the pharynx are often in place during clinical or research evaluations of upper airway function. The purpose of this study was to determine whether the presence of such catheters affects measures of upper airway collapsibility itself. To do so, pharyngeal critical closing pressure (Pcrit) and resistance upstream of the site of collapse Rus) were assessed in 24 propofol-anaesthetized subjects (14 men) with and without a multi-sensor oesophageal catheter (external diameter 2.7 mm) in place. Anaesthetic depth and posture were maintained constant throughout each study. Six subjects had polysomnography(PSG)-defined obstructive sleep apnea (OSA) and 18 either did not have or were at low risk of OSA. Airway patency was maintained with positive airway pressure. At intervals, pressure was reduced by varying amounts to induce varying degrees of inspiratory flow limitation. The slope of the pressure flow relationship for flow-limited breaths defined Rus. Pcrit was similar with the catheter in and out (-1.5 ± 5.4 cmH2 O and -2.1 ± 5.6 cmH2O, respectively, P = 0.14, n = 24). This remained the case both for those with PSG-defined OSA (3.9 ± 2.2 cmH2O and 2.6 ± 1.4 cmH2O, n = 6) and those at low risk/without OSA (-3.3 ± 4.9 cmH2O and -3.7 ± 5.6 cmH2O, respectively, n = 18). Rus was similar with the catheter in and out (20.0 ± 12.3 cmH2O mL(-1) s(-1) and 16.8 ± 10.1 cmH2O mL(-1) s(-1), P = 0.22, n = 24). In conclusion, the presence of a small catheter traversing the pharynx had no significant effect on upper airway collapsibility in these anaesthestized subjects, providing reassurance that such measures can be made reliably in their presence.
Publisher: Wiley
Date: 09-05-2011
DOI: 10.1111/J.1365-2869.2011.00925.X
Abstract: The critical pressure at which the pharynx collapses (Pcrit) is an objective measurement of upper airway collapsibility, an important pathogenetic factor in obstructive sleep apnoea. This study examined the inherent variability of passive Pcrit measurement during sleep and evaluated the effects of sleep stage and body posture on Pcrit. Repeated measurements of Pcrit were assessed in 23 in iduals (15 male) with diagnosed obstructive sleep apnoea throughout a single overnight sleep study. Body posture and sleep stage were unrestricted. Applied upper airway pressure was repetitively reduced to obtain multiple measurements of Pcrit. In 20 subjects multiple measurements of Pcrit were obtained. The overall coefficient of repeatability for Pcrit measurement was 4.1 cm H₂O. Considering only the lateral posture, the coefficient was 4.8 cm H₂O. It was 3.3 cm H₂O in the supine posture. Pcrit decreased from the supine to lateral posture [supine mean 2.5 cm H₂O, 95% confidence interval (CI) 1.4-3.6 lateral mean 0.3 cm H₂O, 95% CI -0.8-1.4, P = 0.007] but did not vary with sleep stage (P = 0.91). This study has shown that the overall coefficient of repeatability was 4.1 cm H₂O, implying that the minimum detectable difference, with 95% probability, between two repeated Pcrit measurements in an in idual is 4.1 cm H₂O. Such variability in overnight measures of Pcrit indicates that a single unqualified value of Pcrit cannot be used to characterize an in idual's overall collapsibility during sleep. When within-subject variability is accounted for, change in body posture from supine to lateral significantly decreases passive pharyngeal collapsibility.
Publisher: Wiley
Date: 04-09-2014
DOI: 10.1111/JSR.12079
Publisher: Oxford University Press (OUP)
Date: 29-11-2020
DOI: 10.1093/SLEEP/ZSZ270
Abstract: In pregnancy, the prevalence of both obstructive sleep apnea (OSA) and depression increases. Research reveals an association in the general population with up to 45% of patients diagnosed with OSA having depressive symptoms. Therefore, this study aimed to investigate the relationship between OSA and depression in pregnant women. One hundred and eighty-nine women ≥26 weeks pregnant were recruited from a tertiary perinatal hospital. This cross-sectional study measured OSA (Apnea Hypopnea Index, AHI, using an ApneaLink device) and symptoms of depression (Edinburgh Postnatal Depression Scale, EPDS). Data were collected from medical records including participant age, ethnicity, parity, BMI, smoking status, history of depression, and use of antidepressants. Of the consenting women, data from 124 were suitable for analysis. Twenty women (16.1%) had OSA (AHI ≥ 5 events/h) and 11 (8.8%) had depressive symptoms (EPDS & 12). Women with OSA were more likely to have depressive symptoms after adjusting for covariates, odds ratio = 8.36, 95% CI [1.57, 44.46]. OSA was also related to higher EPDS scores and these were greater in women with a history of depression. During late pregnancy women with OSA had eight times the odds of having depressive symptoms. Furthermore, an interaction was found between OSA and history of depression. Specifically, in women with no history of depression, OSA increases depressive symptoms. In women with a history of depression, OSA has an even stronger effect on depressive symptomology. This suggests screening for OSA in pregnancy may identify women prone to future depressive episodes and allow for targeted interventions.
Publisher: Elsevier BV
Date: 06-2004
DOI: 10.1016/S1440-2440(04)80008-2
Abstract: The purpose of the current study was to examine the effect of interstate air travel on the quality and quantity of sleep in elite Australian Rules football players. Ten elite male athletes, who were members of a Western Australian-based Australian Football League (AFL) team, participated in the study. Sleep pattern was assessed by measuring sleep duration (SLD), sleep efficiency (SE), number of wakings (NW) and total wake time after sleep onset (WT) using a wrist-worn actigraph. Subjective sleep quality (SQ) was assessed using a scale of sleep rating. Throughout the 2002 AFL season, measurements were obtained on the night before (N1), the night of (N2) and the night after (N3) home and away games. Baseline measurements were obtained from five consecutive non-game nights. Compared to baseline, SLD on N1 was increased when home and away (by 51 and 105 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. On N2, SLD was decreased to a similar degree whether home or away (by 68 and 64 mins respectively, p<0.05), while all other measures of sleep pattern were unchanged. By N3 all measures of sleep pattern had returned to baseline values. Relative to baseline, perception of SQ was worst on N2 of a home game. This study has shown that interstate travel by elite AFL players has no adverse effects on sleep pattern on the night before a game.
Publisher: American Physiological Society
Date: 09-1997
DOI: 10.1152/JAPPL.1997.83.3.768
Abstract: Curran, Aidan K., Peter R. Eastwood, Craig A. Harms, Curtis A. Smith, and Jerome A. Dempsey. Superior laryngeal nerve section alters responses to upper airway distortion in sleeping dogs. J. Appl. Physiol. 83(3): 768–775, 1997.—We investigated the effect of superior laryngeal nerve (SLN) section on expiratory time (Te) and genioglossus electromyogram (EMGgg) responses to upper airway (UA) negative pressure (UANP) in sleeping dogs. The same dogs used in a similar intact study (C. A. Harms, C. A., Y.-J. Zeng, C. A. Smith, E. H. Vidruk, and J. A. Dempsey. J. Appl. Physiol. 80: 1528–1539, 1996) were bilaterally SLN sectioned. After recovery, the UA was isolated while the animal breathed through a tracheostomy. Square waves of negative pressure were applied to the UA from below the larynx or from the mask (nares) at end expiration and held until the next inspiratory effort. Section of the SLN increased eupneic respiratory frequency and minute ventilation. Relative to the same dogs before SLN section, sublaryngeal UANP caused less Te prolongation while activation of the genioglossus required less negative pressures. Mask UANP had no effect on Te or EMGgg activity. We conclude that the SLN 1) is not obligatory for the reflex prolongation of Te and activation of EMGgg activity produced by UANP and 2) plays an important role in the maintenance of UA stability and the pattern of breathing in sleeping dogs.
Publisher: Wiley
Date: 02-2021
DOI: 10.1111/JSR.13286
Abstract: Head posture influences the collapsibility of the passive upper airway during anaesthesia. However, little is known about the impact of head posture during sleep. The objective of this study was to develop and validate an instrument to measure head posture during supine sleep and to apply this instrument to investigate the influence of head posture on obstructive sleep apnea (OSA) severity. A customized instrument to quantify head flexion and rotation during supine sleep was developed and validated in a benchtop experiment. Twenty‐eight participants with suspected OSA were successfully studied using diagnostic polysomnography with the addition of the customized instrument. Head posture in supine sleep was discretized into four categories by two variables: head flexed or not (flexion °) and head rotated or not (rotation °). Sleep time in each posture and the posture‐specific apnea–hypopnea index (AHI) were quantified. Linear mixed‐effect modelling was applied to determine the influence of flexion and rotation on supine OSA severity. Twenty‐four participants had ≥15 min of supine sleep in at least one head‐posture category. Only one participant had ≥15 min of supine sleep time with the head extended. Head flexion was associated with a 12.9 events/h increase in the AHI (95% CI: 3.7–22.1, p = .007). Head rotation was associated with an 11.0 events/h decrease in the AHI (95% CI: 0.3–21.6, p = .04). Despite substantial interparticipant variability, head flexion worsened OSA severity, and head rotation improved OSA severity. Interventions to promote rotation and restrict flexion may have therapeutic benefit in selected patients.
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1093/BJA/AEG126
Abstract: Upper airway obstruction is common during both anaesthesia and sleep. Obstruction is caused by loss of muscle tone present in the awake state. The velopharynx, a particularly narrow segment, is especially predisposed to obstruction in both states. Patients with a tendency to upper airway obstruction during sleep are vulnerable during anaesthesia and sedation. Loss of wakefulness is compounded by depression of airway muscle activity by the agents, and depression of the ability to arouse, so they cannot respond adequately to asphyxia. Identifying the patient at risk is vital. Previous anaesthetic history and investigations of the upper airway are helpful, and a history of upper airway compromise during sleep (snoring, obstructive apnoeas) should be sought. Beyond these, risk identification is essentially a search for factors that narrow the airway. These include obesity, maxillary hypoplasia, mandibular retrusion, bulbar muscle weakness and specific obstructive lesions such as nasal obstruction or adenotonsillar hypertrophy. Such abnormalities not only increase vulnerability to upper airway obstruction during sleep or anaesthesia, but also make intubation difficult. While problems with airway maintenance may be obviated during anaesthesia by the use of aids such as the laryngeal mask airway (LMA( dagger )), identification of risk and caution are keys to management, and the airway should be secured before anaesthesia where doubt exists. If tracheal intubation is needed, spontaneous breathing until intubation is an important principle. Every anaesthetist should have in mind a plan for failed intubation or, worse, failed ventilation.
Publisher: Copernicus GmbH
Date: 22-03-2013
Abstract: Abstract. Several proxy-based and modeling studies have investigated long-term changes in Caribbean climate during the Holocene, however, very little is known on its variability on short timescales. Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca and δ18O measurements on fossil annually banded Diploria strigosa corals from Bonaire. This allows for better understanding of seasonal to multidecadal variability of the Caribbean hydrological cycle during the mid- to late Holocene. The monthly resolved coral Δδ18O records are used as a proxy for the oxygen isotopic composition of seawater (δ18Osw) of the southern Caribbean Sea. Consistent with modern day conditions, annual δ18Osw cycles reconstructed from three modern corals reveal that freshwater budget at the study site is influenced by both net precipitation and advection of tropical freshwater brought by wind-driven surface currents. In contrast, the annual δ18Osw cycle reconstructed from a mid-Holocene coral indicates a sharp peak towards more negative values in summer, suggesting intense summer precipitation at 6 ka BP (before present). In line with this, our model simulations indicate that increased seasonality of the hydrological cycle at 6 ka BP results from enhanced precipitation in summertime. On interannual to multidecadal timescales, the systematic positive correlation observed between reconstructed sea surface temperature and salinity suggests that freshwater discharged from the Orinoco and Amazon rivers and transported into the Caribbean by wind-driven surface currents is a critical component influencing sea surface hydrology on these timescales.
Publisher: Wiley
Date: 20-01-2020
DOI: 10.1111/PAN.13788
Abstract: Obstructive sleep apnea is a common childhood disorder which can lead to serious health problems if left untreated. Enlarged adenoid and tonsils are the commonest causes, and adenotonsillectomy is the recommended first line of treatment. Obstructive sleep apnea poses as an anesthetic challenge, and it is a well-known risk factor for perioperative adverse events. The presence and severity of an obstructive sleep apnea diagnosis will influence anesthesia, pain management, and level of monitoring in recovery period. Preoperative obstructive sleep apnea assessment is necessary, and anesthetists are ideally placed to do so. Currently, there is no standardized approach to the best method of preoperative screening for obstructive sleep apnea. Focused history, clinical assessments, and knowledge regarding the strengths and limitations of available obstructive sleep apnea assessment tools will help recognize a child with obstructive sleep apnea in the preoperative setting.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.ANCLIN.2010.07.003
Abstract: Anesthesia and sleep both predispose to upper airway obstruction through state-induced reductions in pharyngeal dilator muscle activation and lung volume. The tendencies are related in patients with obstructive sleep apnea commonly presenting with difficulties in airway management in the perioperative period. This is a period of great potential vulnerability for such patients because of compromise of the arousal responses that protect against asphyxiation during natural sleep. Careful preoperative evaluation and insightful perioperative observation are likely to identify patients at risk. A significant proportion of patients will have previously undiagnosed obstructive sleep apnea and anesthesiologists are well placed to identify this potential. Patients with known or suspected obstructive sleep apnea need careful postoperative management, particularly while consciousness and arousal responses are impaired. Specific follow-up of suspected cases is needed to ensure that the sleep-related component of the problem receives appropriate care.
Publisher: Informa UK Limited
Date: 29-10-2018
DOI: 10.1080/02640414.2018.1537092
Abstract: The aim of this study was to determine the prevalence of sleep disorders in an elite rugby union team using in-laboratory polysomnography (PSG) and sleep questionnaires. Twenty-five elite rugby union players underwent a night of PSG during the "off-season" of the Super Rugby competition to assess their sleep. Of interest were measurements that detected the presence of obstructive sleep apnea (OSA apnea-hypopnea index ≥5 events/hr) and the presence of moderate-severe periodic leg movements during sleep (PLMs ≥15 events/hr). Players completed sleep-related questionnaires to assess daytime sleepiness, perception of insomnia, risk of OSA, and the presence of restless legs syndrome (RLS) and underwent basic anthropometric assessments including body mass index and neck circumference. OSA was present in 24% (n=6) of players and PLMs ≥15 events/hr in 12% (n=3). Questionnaire responses showed that all players had insomnia defined subthreshold insomnia and excessive daytime sleepiness, two players were identified as being at risk for OSA and none were classified as having RLS. In conclusion, sleep disorders and excessive sleepiness are common in elite rugby union players. A process to identify and manage sleep disorders should be considered by teams to optimise their physical recovery, athletic performance and to safeguard their health.
Publisher: Wiley
Date: 10-1992
DOI: 10.1111/J.1365-2141.1992.TB06422.X
Abstract: Human parvovirus B19 is known to inhibit erythroid colony formation in vitro, but the precise stage of differentiation at which erythroid precursors become capable of supporting viral replication has not been accurately determined. In order to address this issue, haemopoietic cells derived from first trimester fetal liver were cultured in medium containing B19 antigen-positive serum. Infected cells were phenotyped by combining immunohistology for cell-type specific antigens with non-isotopic in situ hybridization for B19 nucleic acid. Strong nuclear hybridization signal was detected as early as 8 h after infection in erythroid precursors labelling with antibodies to glycophorin A, glycophorin C, CD43, CD36 and HLA-ABC (pronormoblast or normoblast phenotype). Giant erythroid precursors labelling with the same five antibodies were a pathognomonic feature of infected cultures, but contained relatively little B19 nucleic acid. Hybridization signal was not detected in progenitor cells of more primitive erythroid phenotype or in nuclei of cells of other lineages, though B19 DNA was occasionally localized within the cytoplasm of macrophages. Double-labelling with antibody Ki-67 confirmed that proliferating cells were targets for B19 infection. Co-detection of cell-type specific antigens and viral nucleic acid is a powerful tool for investigating host cell specificity, and suggests that proliferating late erythroid precursors are the only haemopoietic cells fully permissive for B19 infection.
Publisher: Wiley
Date: 16-03-2020
DOI: 10.1002/JBM.A.36913
Publisher: Informa UK Limited
Date: 2009
DOI: 10.3109/09593980802664711
Abstract: Six-minute walk distance (6MWD) is commonly used as a measure of functional exercise capacity in clinical practice and research. Regression equations to predict 6MWD in healthy in iduals are available, but the equations predict distances that vary considerably for an in idual. The aims of this study were to 1) measure 6MWDs in healthy Caucasian Australians aged 45-85 years 2) determine whether evidence exists for Australian-specific prediction equations for Caucasian in iduals by comparing measured 6MWDs with predicted 6MWDs derived by using published regression equations and 3) develop regression equations for males and females. One hundred nine subjects (48 males) completed the 6-minute walk test (6MWT). Measurements of height, leg length, weight, habitual physical activity, and peak heart rate (HR) achieved during the 6MWT were obtained. 6MWD (better of two tests) was 682 +/- 73 m (mean +/- SD) and 643 +/- 70 m in the males and females, respectively (p<0.01). Published regression equations underestimated 6MWDs in female subjects. Gender-specific regression equations using age and anthropometric data explained 40% and 43% of the variance in 6MWD in males and females, respectively. Validation of the regression equations in a prospective subject cohort is required.
Publisher: Wiley
Date: 30-07-2018
DOI: 10.1111/RESP.13128
Abstract: In patients with COPD, this study evaluated the effect on health-related quality of life (HRQoL) of adding ongoing feedback to a 12-month unsupervised maintenance walking programme. Participants were randomized to either an intervention group (IG) or control group (CG). Both groups completed the same 2-month supervised, walking training programme followed by a 12-month unsupervised maintenance walking programme. During the maintenance programme, the IG received ongoing feedback (telephone calls, biofeedback and progressive goal setting) and the CG received no feedback. A total of 75 participants completed the study (mean (SD): age 69 (8) years forced expiratory volume in 1 s (FEV Following a 2-month supervised walking training programme, ongoing feedback was no more effective than no feedback in maintaining HRQoL during a 12-month unsupervised walking programme.
Publisher: Elsevier BV
Date: 09-2004
Publisher: Springer Science and Business Media LLC
Date: 29-06-2017
Publisher: American Physiological Society
Date: 08-1995
DOI: 10.1152/JAPPL.1995.79.2.632
Abstract: Transcutaneous bilateral phrenic nerve stimulation (tPNS) is frequently used to assess diaphragmatic function in humans. Commonly, stimulation is performed with hand-held electrodes however, these are unsuitable for studies requiring repeated PNS and where recruitment of rib cage and neck muscles may shift the probes in relation to the nerves. In this study we describe the design of a cervical neck brace and electrode probes that maintain stimulating electrodes in constant position relative to the phrenic nerves and facilitates studies requiring repeated maximal PNS. The effectiveness of the apparatus was examined by 1) reviewing the reproducibility of the transdiaphragmatic pressure response to 0.1 ms tPNS (PdiT) at relaxed functional residual capacity in four subjects studied on 25 +/- 8 (SD) occasions ( or = 24 h apart) over a 4-yr period, and 2) measuring peak-to-peak litude of the left and right diaphragmatic compound muscle action potentials (surface electrodes) during two prolonged studies (38 +/- 9 min) in each subject, when tPNS was performed during repeated submaximal and maximal inspiratory efforts. PdiT was reproducible in each subject when measured repeatedly within a single study [coefficient of variation (CV) of 3.8 +/- 0.8%] and over separate days (CV of 11.5 +/- 3.5%). The peak-to-peak litudes of the left and right compound muscle action potentials were also reproducible (CV of 8.4 +/- 4.3 and 8.4 +/- 2.9%, respectively) and independent of the degree of effort. The apparatus appears effective for the maintenance of maximal stimulation under varied conditions for long periods and provides reproducible measurements of PdiT both within and between studies.
Publisher: Wiley
Date: 31-07-2019
DOI: 10.1111/JSR.12741
Abstract: Restless legs syndrome has been associated with serum iron deficiency in clinical studies. However, studies investigating this relationship have had inconsistent results and there are no studies in young adults. Therefore, we investigated the relationship between serum measures of iron stores and restless legs syndrome in young adults in the community. Participants in the Western Australian Pregnancy Cohort (Raine) Study answered questions on restless legs syndrome (n = 1,100, 54% female) at age 22 years, and provided serum measures of iron stores (ferritin and transferrin saturation) at ages 17 and 22 years. Restless legs syndrome was diagnosed when four International RLS Study Group criteria were met (urge to move, dysaesthesia, relief by movement, worsening during evening/night) and these symptoms occurred ≥5 times per month. Logistic regression was used to assess associations between serum iron stores and restless legs syndrome, adjusting for potential confounders. The prevalence of restless legs syndrome at age 22 years was 3.0% (n = 33, 70% female). Among those who provided restless legs syndrome and iron data at age 22 years (n = 865), the median (interquartile range) ferritin was not different between the restless legs syndrome (55 [29.5-103.5] µg L
Publisher: Wiley
Date: 25-11-2017
DOI: 10.1111/RESP.12959
Publisher: American Psychological Association (APA)
Date: 2015
DOI: 10.1037/TPS0000021
Publisher: Springer Science and Business Media LLC
Date: 18-01-2018
DOI: 10.1007/S00420-018-1289-4
Abstract: The average Australian working week in middle-aged and older workers exceeds government recommendations. Long working weeks are associated with poor health outcomes however, the relationship between long working weeks and health in young Australian workers is unknown. Data were drawn from the 22-year follow-up of the Western Australian Pregnancy Cohort (Raine) Study in Perth, Western Australia. Information was available from 873 young adults about working hours per week, shift work and sleep duration. Blood s les provided measures of cardiometabolic risk (CMR) factors. Almost one-third (32.8%) of young workers reported > 38 h working weeks. This was commonly reported in mining and construction industries for males health and social assistance, mining and retail trade industries for females. CMR factors including increased waist circumference, higher fasting plasma glucose and reduced HDL cholesterol were associated with > 38 h working weeks. These relationships were not moderated by gender or by BMI for glucose and HDL cholesterol. Total sleep time was significantly lower in both male and female workers reporting > 38 h working weeks, but did not mediate the relationships seen with CMR factors. These findings point to early associations between > 38 h working weeks and CMR risk, and highlight the potential benefit of making young employees aware of the health associations with working arrangements to reduce the longer-term relationships seen with working hours and poor cardiometabolic health in population studies.
Publisher: American Thoracic Society
Date: 05-2001
DOI: 10.1164/AJRCCM.163.6.2004169
Abstract: In six dogs studied in nonrapid eye movement (NREM) sleep, we found that the frequency, volume, and timing of application of mechanical ventilator breaths had marked and sustained inhibitory effects on diaphragm electromyogram (EMG(di)). Single ventilator breaths of tidal volume (VT) 75-200% of control caused apnea (up to three times eupneic expiratory time [TE]) when applied during the initial 25-65% of expiratory time. When continuous controlled mechanical ventilation (CMV) was applied with ventilator frequency increased as little as 1 cycle/min > eupnea and Pa(CO(2)) and VT maintained at near eupneic control levels, EMG(di) was silenced and triangularis sterni EMG (EMG(ts)) became tonic within 2 to 5 ventilator cycles. On cessation of normocapnic CMV, apnea ensued with TE ranging from 1.2 to five times eupneic TE. The spontaneous VT and EMG(di) determined immediately after these prolonged apneas were also markedly reduced in litude. The larger the VT applied during the isocapnic CMV (120-200% of eupnea) and the longer the duration of the CMV (3-90 s), the longer the duration of the postventilator apnea. Significant postventilator apneas and postapneic hypoventilation also occurred even when end-tidal CO(2) pressure (PET(CO(2))) was raised 3-5 mm Hg > eupnea (and 7-10 mm Hg > normal apneic threshold) throughout CMV trials at raised frequency and VT. Our findings demonstrate that the increased frequency of CMV was critical to the elimination of inspiratory motor output and the onset of tonic expiratory muscle activity furthermore, once EMG(di) was silenced, the tidal volume and duration of the passive mechanical ventilation determined the magnitude of the short-term inhibition of inspiratory motor output after cessation of CMV.
Publisher: Oxford University Press (OUP)
Date: 11-2008
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-04-2020
DOI: 10.14309/AJG.0000000000000627
Abstract: Night-time gastroesophageal reflux (nGER) symptoms are commonly associated with interrupted sleep. Most studies attempting to understand the relationship between sleep, arousal, and nGER events have been performed so using accelerometry however, this technology is limited in its ability to precisely determine the temporal association between sleep and reflux events. We aimed to examine the temporal relationships between nGER events and arousal/awakening from sleep using high resolution, in-laboratory polysomnography (PSG). In iduals between 18 and 70 years who had undergone a gastroscopy within 12 months underwent simultaneous 24-hour pH/impedance monitoring and in-laboratory PSG. The temporal relationship between each nGER event and sleep/arousals/awakenings was determined for each participant. Analyses were limited to the sleep period (between “lights out” and time of final waking). Analyses were conducted on the data from 25 in iduals, 64% of whom had nGER episodes (5 ± 5 events per person, range 1–18) and 64% of whom had obstructive sleep apnea (OSA, mean apnea–hypopnea index 20 ± 11 events/hr, range 6–44). There were no differences in PSG-determined sleep duration, sleep efficiency, sleep architecture, arousals/awakenings, or sleep apnea severity between those with nGER and those without. Most nGER events (82%) occurred during a PSG epoch that had been classified as wake. Arousals/awakenings preceded almost all events (73/76), whereas fewer had an arousal/awakening after the event (15/76). As opposed to what is typically assumed, nGER does not seem to cause arousal from sleep, but rather arousal from sleep predisposes to nGER.
Publisher: Springer Science and Business Media LLC
Date: 22-01-2010
Publisher: Informa UK Limited
Date: 31-01-2018
DOI: 10.1080/02640414.2018.1433443
Abstract: The 10-min Psychomotor Vigilance Test (PVT-10) is regarded as the gold-standard for assessing vigilant attention following sleep loss however, other studies have investigated whether shorter versions of the test elicit similar results to the PVT-10. The present study compared the PVT-10 with 3-min (PVT-3) and 5-min (PVT-5) versions of the test in elite female basketball players. Athletes performed all three tests in the morning and evening for seven consecutive days. Response speed (mean reciprocal reaction time mean 1/RT), number of errors and number of lapses were determined for each test and time point. The PVT-3 elicited significantly faster response speeds than the other two tests (p < 0.01), while the PVT-5 and PVT-10 were not different. The PVT-10 resulted in more lapses than the PVT-5, followed by the PVT-3, with all tests being significantly different to each other (p < 0.01). In conclusion, while the PVT-5 and PVT-10 were generally similar for response speed, the PVT-3 did not produce results comparable with the PVT-10 for response speed, lapses or errors, and should therefore not be used interchangeably. Further research is required to determine whether the shorter tests are a suitable replacement for the PVT-10 in professional basketball players.
Publisher: Springer Science and Business Media LLC
Date: 14-10-2015
Publisher: Wiley
Date: 26-12-2012
DOI: 10.1111/J.1440-1843.2012.02255.X
Abstract: Adult obstructive sleep apnoea (OSA) is associated with cognitive dysfunction. While many review articles have attempted to summarize the evidence for this association, it remains difficult to determine which domains of cognition are affected by OSA. This is because of marked differences in the nature of these reviews (e.g. many are unsystematic) and the many different tasks and domains assessed. This paper addresses this issue by comparing the results of only systematic reviews or meta-analyses assessing the effects of OSA on cognition, the relationship between OSA severity and cognition, and/or the effects of treatment on cognition in OSA. Electronic databases and hand-searching were undertaken to select reviews that reported on these areas. We found 33 reviews five reviews met predetermined, stringent selection criteria. The majority of reviews supported deficits in attention/vigilance, delayed long-term visual and verbal memory, visuospatial/constructional abilities, and executive function in in iduals with OSA. There is also general agreement that language ability and psychomotor function are unaffected by OSA. Data are equivocal for the effects of OSA on working memory, short-term memory and global cognitive functioning. Attention/vigilance dysfunction appears to be associated with sleep fragmentation and global cognitive function with hypoxaemia. Continuous positive airway pressure treatment of OSA appears to improve executive dysfunction, delayed long-term verbal and visual memory, attention/vigilance and global cognitive functioning. In order to improve our understanding of cognitive dysfunction in OSA, future research should pay particular attention to participant characteristics, measures of disease severity and choice of neuropsychological tests.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2020
Publisher: American Physiological Society
Date: 11-2001
DOI: 10.1152/JAPPL.2001.91.5.1913
Abstract: To examine the effect of hyperinflation on the volume displaced by diaphragm motion (ΔVdi), we compared nine subjects with emphysema and severe hyperinflation [residual volume (RV)/total lung capacity (TLC) 0.65 ± 0.08 mean ± SD] with 10 healthy controls. Posteroanterior and lateral chest X rays at RV, functional residual capacity, one-half inspiratory capacity, and TLC were used to measure the length of diaphragm apposed to ribcage (Lap), cross-sectional area of the pulmonary ribcage, ΔVdi, and volume beneath the lung-apposed dome of the diaphragm. Emphysema subjects, relative to controls, had increased Lap at comparable lung volumes (4.3 vs. 1.0 cm near predicted TLC, 95% confidence interval 3.4–5.2 vs. 0–2.1), pulmonary rib cage cross-sectional area (emphysema/controls 1.22 ± 0.03, P 0.001 at functional residual capacity), and ΔVdi/ΔLap (0.25 vs. 0.14 liters/cm, P 0.05). During a vital capacity inspiration, relative to controls, ΔVdi was normal in five (1.94 ± 0.51 liters) and decreased in four (0.51 ± 0.40 liters) emphysema subjects, and volume beneath the dome did not increase in emphysema (0 ± 0.36 vs. 0.82 ± 0.80 liters, P 0.05). We conclude that ΔVdi can be normal in emphysema because 1) hyperinflation is shared between ribcage and diaphragm, preserving Lap, and 2) the diaphragm remains flat during inspiration.
Publisher: The Optical Society
Date: 15-10-2008
DOI: 10.1364/OE.16.017521
Abstract: Endoscopic treatment of lower airway pathologies requires accurate quantification of airway dimensions. We demonstrate the application of a real-time endoscopic optical coherence tomography system that can image lower airway anatomy and quantify airway lumen dimensions intra-operatively. Results demonstrate the ability to acquire 3D scans of airway anatomy and include comparison against a pre-operative X-ray CT. The paper also illustrates the capability of the system to assess the real-time dynamic changes within the airway that occur during respiration.
Publisher: Wiley
Date: 06-09-2015
DOI: 10.1111/RESP.12621
Publisher: Elsevier BV
Date: 10-2023
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-04-2021
Publisher: American Physiological Society
Date: 03-1998
DOI: 10.1152/JAPPL.1998.84.3.1063
Abstract: To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (Ti) increased during wakefulness, non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM) sleep (155 ± 8, 164 ± 11, and 161 ± 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent 2) Ti further increased during wakefulness and NREM (215 ± 52 and 197 ± 28%, respectively) but nonsignificantly during REM sleep (196 ± 42%) 3) mean rate of rise of diaphragm EMG (EMGdi/Ti) and rate of fall of tracheal pressure (Ptr/Ti) were decreased, reflecting an additional inhibitory input from UA receptors and 4) both EMGdi/Ti and Ptr/Ti were decreased proportionately more as inspiration proceeded, suggesting greater reflex inhibition later in the effort. Similar inhibitory effects of exposing the UA to negative pressure (via an open tracheal Fen) were seen when an inspiratory resistive load was applied over several breaths during wakefulness and sleep. These inhibitory effects persisted even in the face of rising chemical stimuli. This inhibition of inspiratory motor output is alinear within an inspiration and reflects the activation of UA pressure-sensitive receptors by UA distortion, with greater distortion possibly occurring later in the effort.
Publisher: American Thoracic Society
Date: 11-1999
DOI: 10.1164/AJRCCM.160.5.9806135
Abstract: To examine mechanisms responsible for reduced lung volumes (restriction) in asbestos-related pleural fibrosis (APF), we studied diaphragm function and lower rib-cage excursion in 26 subjects with previous asbestos exposure and no evidence of asbestosis. Using posteroanterior (PA) and lateral chest radiographs taken at residual volume and at 25%, 70%, and 100% vital capacity (VC) during a slow inspiratory maneuver, we measured fractional expansion of the lower rib cage (FErc), fractional shortening of the diaphragm (FSdi), and changes (Delta) in diaphragm dome height (Hdo) and subphrenic volume (Vdi). Vdi was estimated by measuring the major and minor axes of the subphrenic space at 1-cm intervals, assuming an elliptical cross-sectional shape, and correcting for the volume of spinal and paraspinal tissues. Seven subjects had no evidence of APF (control), 12 had pleural plaques (PP), and seven had diffuse pleural thickening with costophrenic obliteration (DPT). Over the range of VC, results (mean +/- SEM, normalized for height) in control subjects were VC = 101.2 +/- 4.0 % predicted and DeltaVdi = 326 +/- 8 ml/m(3), and for the right hemithorax and hemidiaphragm on the PA film, FErc = 0.07 +/- 0.02, FSdi = 0.32 +/- 0.02 and DeltaHdo = 0.8 +/- 0.2 cm/m. Relative to controls: DPT subjects had reduced VC (77.4 +/- 4.9%, p < 0.01), DeltaVdi (256 +/- 2 ml/m(3), p < 0.01), FErc (0.01 +/- 0.02, p < 0.01), FSdi (0.24 +/- 0.01, p < 0.001), and DeltaHdo (-0.9 +/- 0.06 cm/m, p < 0.01) PP subjects had reduced FSdi (0.25 +/- 0.01, p < 0.001) and DeltaVdi (233 +/- 47 ml/m(3), p < 0.01), and no difference in FErc, DeltaHdo, or VC. We conclude that restriction in DPT is due to obliteration of the zone of apposition, and that by limiting separation of the diaphragm from the rib cage during inspiration, this reduces volume contributed by motion of the diaphragm and lower rib cage. Reduction in the latter contribution was the main cause of restriction, because the reduction in volume contributed by the diaphragm was partly compensated by flattening of its dome.
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.88_12619
Publisher: Wiley
Date: 25-06-2023
DOI: 10.5694/MJA2.52014
Abstract: To examine associations between three clinically significant sleep disorders (chronic insomnia, obstructive sleep apnoea, restless legs syndrome) and workplace productivity losses among young Australian adults. Prospective, observational study 22‐year follow‐up of participants in the longitudinal birth cohort Raine Study (Perth, Western Australia). Currently employed 22‐year‐old Raine Study participants who underwent in‐laboratory sleep disorder screening for moderate to severe obstructive sleep apnoea (apnoea–hypopnea index of more than fifteen events/hour or obstructive sleep apnoea syndrome) and were assessed for insomnia and restless legs syndrome using validated measures. Total workplace productivity loss over twelve months, assessed with the World Health Organization Health and Work Performance Questionnaire. Of 1235 contactable 22‐year‐old Raine Study cohort members, 554 people (44.9% 294 women [53%]) underwent overnight polysomnography, completed the baseline sleep questionnaire, and completed at least three quarterly workplace productivity assessments. One or more clinically significant sleep disorders were identified in 120 participants (21.7%) 90 participants had insomnia (17%), thirty clinically significant obstructive sleep apnoea (5.4%), and two restless legs syndrome (0.4%). Seventeen people (14% of those with sleep disorders) had previously been diagnosed with a sleep disturbance by a health professional, including fourteen with insomnia. Median total workplace productivity loss was greater for participants with sleep disorders (164 hours/year interquartile range [IQR], 0–411 hours/year) than for those without sleep disorders (30 hours/year IQR, 0–202 hours/year) total workplace productivity loss was 40% greater for participants with sleep disorders (adjusted incidence rate ratio, 1.40 bias‐corrected and accelerated 95% confidence interval, 1.10–1.76). The estimated population total productivity loss (weighted for disorder prevalence) was 28 644 hours per 1000 young workers per year, primarily attributable to insomnia (28 730 hours/1000 workers/year). Insomnia is a risk factor for workplace productivity loss in young workers. Tailored interventions are needed to identify and manage sleep disorders, particularly as most of the sleep disorders detected in the Raine Study had not previously been diagnosed.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.JBIOMECH.2013.07.007
Abstract: The most collapsible part of the upper airway in the majority of in iduals is the velopharynx which is the segment positioned behind the soft palate. As such it is an important morphological region for consideration in elucidating the pathogenesis of obstructive sleep apnea (OSA). This study compared steady flow properties during inspiration in the pharynges of nine male subjects with OSA and nine body-mass index (BMI)- and age-matched control male subjects without OSA. The k-ωSST turbulence model was used to simulate the flow field in subject-specific pharyngeal geometric models reconstructed from anatomical optical coherence tomography (aOCT) data. While analysis of the geometry of reconstructed pharynges revealed narrowing at velopharyngeal level in subjects with OSA, it was not possible to clearly distinguish them from subjects without OSA on the basis of pharyngeal size and shape alone. By contrast, flow simulations demonstrated that pressure fields within the narrowed airway segments were sensitive to small differences in geometry and could lead to significantly different intraluminal pressure characteristics between subjects. The ratio between velopharyngeal and total pharyngeal pressure drops emerged as a relevant flow-based criterion by which subjects with OSA could be differentiated from those without.
Publisher: Oxford University Press (OUP)
Date: 11-06-2021
Abstract: This randomized, double-blind, placebo-controlled, crossover study was conducted to evaluate the safety and efficacy of 2 weeks of nightly sublingual cannabinoid extract (ZTL-101) in treating chronic insomnia (symptoms ≥3 months). Co-primary study endpoints were safety of the medication based on adverse event reporting and global insomnia symptoms (Insomnia Severity Index [ISI]). Secondary endpoints included: self-reported (sleep diary), actigraphy-derived, and polysomnography measurements of sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), sleep efficiency (SE) and self-reported assessments of sleep quality (sSQ) and feeling rested upon waking. Adjusted mean differences between placebo and ZTL-101 were calculated. Twenty-three of 24 randomized participants (n = 20 female, mean age 53 ± 9 years) completed the protocol. No serious adverse events were reported. Forty mild, nonserious, adverse events were reported (36 during ZTL-101) with all but one resolving overnight or soon after waking. Compared to placebo, ZTL-101 decreased ISI (−5.07 units [95% CI: −7.28 to −2.86] p = 0.0001) and self-reported SOL (−8.45 min [95% CI: −16.33 to −0.57] p = 0.04) and increased self-reported TST (64.6 min [95% CI: 41.70 to 87.46] p & 0.0001), sSQ (0.74 units [95% CI: 0.51 to 0.97] p & 0.0001), and feeling of being rested on waking (0.51 units [95% CI: 0.24 to 0.78] p = 0.0007). ZTL-101 also decreased actigraphy-derived WASO (−10.2 min [95% CI: −16.2 to −4.2] p = 0.002), and increased actigraphy-derived TST (33.4 min [95% CI: 23.07 to 43.76] p & 0.001) and SE (2.9% [95% CI: 2.0 to 3.8] p = 0.005). Two weeks of nightly sublingual administration of a cannabinoid extract (ZTL-101) is well tolerated and improves insomnia symptoms and sleep quality in in iduals with chronic insomnia symptoms. ANZCTR anzctr.org.au ACTRN12618000078257.
Publisher: Elsevier BV
Date: 2020
DOI: 10.1016/J.JNS.2019.116522
Abstract: Hypothalamic pathology is a well-documented feature of Huntington's disease (HD) and is believed to contribute to circadian rhythm and habitual sleep disturbances. Currently, no therapies exist to combat hypothalamic changes, nor circadian rhythm and habitual sleep disturbances in HD. To evaluate the effects of multidisciplinary rehabilitation on hypothalamic volume, brain-derived neurotrophic factor (BDNF), circadian rhythm and habitual sleep in in iduals with preclinical HD. Eighteen in iduals with HD (ten premanifest and eight prodromal) undertook a nine-month multidisciplinary rehabilitation intervention (intervention group), which included exercise, cognitive and dual task training and social events, and were compared to a community s le of eleven in iduals with premanifest HD receiving no intervention (control group). Hypothalamic volume, serum BDNF, salivary cortisol and melatonin concentrations, subjective sleep quality, daytime somnolence, habitual sleep-wake patterns, stress and anxiety and depression symptomatology were evaluated. Hypothalamus grey matter volume loss was significantly attenuated in the intervention group compared to the control group after controlling for age, gender, Unified Huntington's Disease Rating Scale-Total Motor Score and number of cytosine-adenine-guanine repeats. Serum BDNF levels were maintained in the intervention group, but decreased in the control group following the study period. Both groups exhibited decreases in cortisol and melatonin concentrations. No changes were observed in sleep or mood outcomes. This exploratory study provides evidence that multidisciplinary rehabilitation can reduce hypothalamic volume loss and maintain peripheral BDNF levels in in iduals with preclinical HD but may not impact on circadian rhythm. Larger, randomised controlled trials are required to confirm these findings.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-09-2020
DOI: 10.5664/JCSM.8564
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2009
Publisher: Springer Singapore
Date: 28-11-2018
Publisher: Hindawi Limited
Date: 15-12-2020
DOI: 10.1002/TSM2.218
Publisher: Springer Science and Business Media LLC
Date: 28-08-2013
DOI: 10.1007/S11325-012-0763-6
Abstract: The Epworth Sleepiness Scale (ESS) is a widely used tool for measuring sleepiness. In addition to providing a single measure of sleepiness (a one-factor structure), the ESS also has the capacity to provide additional information about specific factors that facilitate sleep onset, including a person's posture, activity and environment. These features of sleepiness are referred to as somnificity. This study evaluates and compares the fit of a one-factor structure (sleepiness) and three-factor structure (reflecting low, medium and high levels of somnificity) for the ESS. All participants (a community s le N = 356 and a clinical s le N = 679) were administered the ESS. Confirmatory factor analysis was used to evaluate and compare the fit of one- and three-factor models of the ESS. In both s les, a three-factor structure (community s le adjusted X (2) = 2.95, root mean square error of approximation (RMSEA) = 0.07, Comparative Fit Index (CFI) = 0.95 clinical s le adjusted X (2) = 3.98, RMSEA = 0.07, CFI = 0.98) provided a level of model fit that was at least as good as the one-factor structure (community s le adjusted X (2) = 5.01, RMSEA = 0.11, CFI = 0.87 clinical s le adjusted X (2) = 8.87, RMSEA = 0.11, CFI = 0.92). In addition to a single measure of sleepiness, the ESS can provide subscale scores which relate to three underlying levels of somnificity. These findings suggest that the ESS can be used to measure an in idual's overall sleep propensity as well as more specific measures of sleep propensity in low, moderate and high levels of situational somnificity.
Publisher: Wiley
Date: 10-2018
Publisher: American Physiological Society
Date: 08-2013
DOI: 10.1152/JAPPLPHYSIOL.01199.2012
Abstract: Increasing lung volume increases upper airway patency and decreases airway resistance and collapsibility. The role of diaphragm contraction in producing these changes remains unclear. This study was undertaken to determine the effect of selective diaphragm contraction, induced by phrenic nerve stimulation, on upper airway collapsibility and the extent to which any observed change was attributable to lung volume-related changes in pressure gradients or to diaphragm descent-related mediastinal traction. Continuous bilateral transcutaneous cervical phrenic nerve stimulation (30 Hz) was applied to nine supine, anesthetized human subjects during transient decreases in airway pressure to levels sufficient to produce flow limitation when unstimulated. Stimulation was applied at two intensities (low and high) and its effects on lung volume and airflow quantified relative to unstimulated conditions. Lung volume increased by 386 ± 269 ml (means ± SD) and 761 ± 556 ml during low and high stimulation, respectively ( P 0.05 for the difference between these values), which was associated with peak inspiratory flow increases of 69 ± 57 and 137 ± 108 ml/s, respectively ( P 0.05 for the difference). Stimulation-induced change in lung volume correlated with change in peak flow ( r = 0.65, P 0.01). Diaphragm descent-related outward displacement of the abdominal wall produced no change in airflow unless accompanied by lung volume change. We conclude that phrenic nerve stimulation-induced diaphragm contraction increases lung volume and reduces airway collapsibility in a dose-dependent manner. The effect appears primarily mediated by changes in lung volume rather than mediastinal traction from diaphragm descent. The study provides a rationale for use of continuous phrenic stimulation to treat obstructive sleep apnea.
Publisher: Elsevier BV
Date: 10-2023
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-01-2013
DOI: 10.5664/JCSM.2328
Publisher: Informa UK Limited
Date: 30-06-2021
DOI: 10.1080/02640414.2021.1947617
Abstract: There is a scarcity of research examining the effects of long-distance transmeridian travel (LDTT) on the sleep and match performance of team sport players. To address this, 37 elite male rugby union players from a Super Rugby team undertaking LDTT were recruited. The participants completed validated sleep questionnaires and wore a wrist-worn activity monitor (Readiband™) during a Super Rugby season (including during periods of LDTT crossing 5, 6, and 13 time-zones) to ascertain objective measures of sleep. Sleep measures were compared using mixed model analysis to ascertain the effects of competition and LDTT on sleep. Total sleep time (TST) increased in the days prior to matches, and decreased following matches (accompanied by a later time at sleep onset), particularly when next-day early-morning flights were required. TST was decreased when sleep was attempted during LDTT, except for in the last travel bout where players napped in addition to achieving night-time sleep. TST was also reduced for the night immediately following LDTT, except for in Condition 3 where players delayed wake time and also achieved naps. This study exemplifies the challenges that team-sport athletes face in obtaining regular sleep when LDTT is required.
Publisher: IOP Publishing
Date: 21-09-2016
DOI: 10.1088/0967-3334/37/10/1636
Abstract: Researchers are increasingly using 24 h accelerometer wear protocols. No automated method has been published that accurately distinguishes 'waking' wear time from other data ('in-bed', non-wear, invalid days) in young adults. This study examined the validity of an automated algorithm developed to achieve this for hip-worn Actigraph GT3X + 60 s epoch data. We compared the algorithm against a referent method ('into-bed' and 'out-of-bed' times visually identified by two independent raters) and benchmarked against two published algorithms. All methods used the same non-wear rules. The development s le (n = 11) and validation s le (n = 95) were Australian young adults from the Raine pregnancy cohort (54% female), all aged approximately 22 years. The agreement with Rater 1 in each minute's classification (yes/no) of waking wear time was examined as kappa (κ), limited to valid days (⩾10 h waking wear time per day) according to the algorithm and Rater 1. Bland-Altman methods assessed agreement in daily totals of waking wear and in-bed wear time. Excellent agreement (κ > 0.75) was obtained between the raters for 80% of participants (median κ = 0.94). The algorithm showed excellent agreement with Rater 1 (κ > 0.75) for 89% of participants and poor agreement (κ < 0.40) for 1%. In this s le, the algorithm (median κ = 0.86) performed better than algorithms validated in children (median κ = 0.77) and adolescents (median κ = 0.66). The mean difference (95% limits of agreement) between Rater 1 and the algorithm was 7 (-220, 234) min d
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.30_12618
Publisher: SAGE Publications
Date: 24-02-2017
Abstract: We described physical activity measures and hourly patterns in patients with chronic obstructive pulmonary disease (COPD) after stratification for generic and COPD-specific characteristics and, based on multiple physical activity measures, we identified clusters of patients. In total, 1001 patients with COPD (65% men age, 67 years forced expiratory volume in the first second [FEV 1 ], 49% predicted) were studied cross-sectionally. Demographics, anthropometrics, lung function and clinical data were assessed. Daily physical activity measures and hourly patterns were analysed based on data from a multisensor armband. Principal component analysis (PCA) and cluster analysis were applied to physical activity measures to identify clusters. Age, body mass index (BMI), dyspnoea grade and ADO index (including age, dyspnoea and airflow obstruction) were associated with physical activity measures and hourly patterns. Five clusters were identified based on three PCA components, which accounted for 60% of variance of the data. Importantly, couch potatoes (i.e. the most inactive cluster) were characterised by higher BMI, lower FEV 1 , worse dyspnoea and higher ADO index compared to other clusters ( p 0.05 for all). Daily physical activity measures and hourly patterns are heterogeneous in COPD. Clusters of patients were identified solely based on physical activity data. These findings may be useful to develop interventions aiming to promote physical activity in COPD.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 06-2022
DOI: 10.5664/JCSM.9886
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2017
DOI: 10.1519/JSC.0000000000001697
Abstract: Dunican, IC, Martin, DT, Halson, SL, Reale, RJ, Dawson, BT, Caldwell, JA, Jones, MJ, and Eastwood, PR. The effects of the removal of electronic devices for 48 hours on sleep in elite judo athletes. J Strength Cond Res 31(10): 2832–2839, 2017—This study examined the effects of evening use of electronic devices (i.e., smartphones, etc.) on sleep quality and next-day athletic and cognitive performance in elite judo athletes. Over 6 consecutive days and nights, 23 elite Australian judo athletes were monitored while attending a c at the Australian Institute of Sport (AIS). In 14 athletes, all electronic devices were removed on days 3 and 4 (i.e., for 48 hours: the “device-restricted group”), whereas 9 were permitted to use their devices throughout the c (the “control group”). All athletes wore an activity monitor (Readiband) continuously to provide measures of sleep quantity and quality. Other self-reported (diary) measures included time in bed, electronic device use, and rate of perceived exertion during training periods. Cognitive performance (Cogstate) and physical performance (single leg triple hop test) were also measured. When considering night 2 as a “baseline” for each group, removal of electronic devices on nights 3 and 4 (device-restricted group) resulted in no significant differences in any sleep-related measure between the groups. When comparing actigraphy-based measures of sleep to subjective measures, all athletes significantly overestimated sleep duration by 58 ± 85 minutes ( p = 0.001) per night and underestimated time of sleep onset by 37 ± 72 minutes ( p = 0.001) per night. No differences in physical or cognitive function were observed between the groups. Conclusion: This study has shown that the removal of electronic devices for a period of two nights (48 hours) during a judo c does not affect sleep quality or quantity or influence athletic or cognitive performance.
Publisher: Wiley
Date: 24-08-2019
DOI: 10.1111/ANZS.12270
Publisher: European Respiratory Society
Date: 28-09-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2010
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1007/BF00164171
Publisher: Elsevier BV
Date: 12-2019
Publisher: Springer Science and Business Media LLC
Date: 06-1993
DOI: 10.1007/BF00157806
Publisher: European Respiratory Society (ERS)
Date: 09-2007
DOI: 10.1183/09031936.00095406
Abstract: The aim of the present study was to determine the relative value of incremental and constant load tests in detecting changes in inspiratory muscle endurance following high-intensity inspiratory muscle training (H-IMT) in chronic obstructive pulmonary disease. In total, 16 subjects (11 males forced expiratory volume in one second (FEV(1)) 37.4+/-12.5%) underwent H-IMT. In addition, 17 subjects (11 males FEV(1) 36.5+/-11.5%) underwent sham inspiratory muscle training (S-IMT). Training took place three times a week for 8 weeks. Baseline and post-training measurements were obtained of maximum threshold pressure sustained during an incremental load test (P(th,max)) and time breathing against a constant load (t(lim)). Breathing pattern was unconstrained. H-IMT increased P(th,max) and t(lim) relative to baseline and to any change seen following S-IMT. The effect size for P(th,max) was greater than for t(lim). Post-training tests were accompanied by changes in breathing pattern, including decreased duty cycle, which may have served to decrease inspiratory work and thereby contribute to the increase in P(th,max) and t(lim) in both groups. When assessing inspiratory muscle function in chronic obstructive pulmonary disease via tests in which the pattern of breathing is unconstrained, the current authors recommend incremental load tests be used in preference to constant load tests. However, to attribute changes in these tests to improvements in inspiratory muscle endurance, breathing pattern should be controlled.
Publisher: Wiley
Date: 03-2018
Publisher: Wiley
Date: 24-05-2021
DOI: 10.1111/JSR.13361
Abstract: Children with intellectual disabilities are more likely to experience sleep disorders of insomnia, excessive daytime sleepiness and sleep breathing disorders than typically developing children. The present study examined risk factors for these sleep disorders in 447 children (aged 5–18 years), diagnosed with an intellectual disability and comorbid autism spectrum disorder, cerebral palsy, Down syndrome or Rett syndrome. Primary caregivers reported on their child’s sleep using the Sleep Disturbance Scale for Children (SDSC), as well as medical comorbidities and functional abilities. Multivariate linear and logistic regressions were used to examine the effects of these factors on SDSC t scores and a binary indicator, respectively for the relevant subscales. Receiving operating characteristic curves were generated for each logistic regression model to determine their ability to discriminate between poor and good sleep. Comorbidities rather than functional abilities were associated with poorer sleep. In particular, recurrent pain, frequent seizures, frequent coughing, constipation and prescription of sleep medications were associated with abnormal sleep across the entire s le, but predictors differed between diagnostic groups. The present study suggests that comorbidities are more strongly associated with quality of sleep than functional impairments. The present study provides new information on potential associations between frequent coughing, prescription sleep medications and sleep quality that should be further investigated.
Publisher: Wiley
Date: 23-12-2011
DOI: 10.1111/J.1440-1843.2010.01888.X
Abstract: Airway diseases are a major concern around the world. However, the pace of new drug and biomarker discovery has lagged behind those of other common disorders such as cardiovascular diseases and diabetes. One major barrier in airway research has been the inability to accurately visualize large or small airway remodelling or dysplastic/neoplastic (either pre or early cancerous) changes using non- or minimally invasive instruments. The advent of optical coherence tomography (OCT) has the potential to revolutionize airway research and management by allowing investigators and clinicians to visualize the airway with resolution approaching histology and without exposing patients to harmful effects of ionizing radiation. Thus, with the aid of OCT, we may be able to accurately determine and quantify the extent of airway remodelling in asthma and chronic obstructive pulmonary disease, detect early pre-cancerous lesions in smokers for chemoprevention, study the upper airway anatomy of patients with obstructive sleep apnea in real time while they are asleep and facilitate optimal selection of stents for those with tracheal obstruction. In this paper, we review the current state of knowledge of OCT and its possible application in airway diseases.
Publisher: Wiley
Date: 06-11-2018
DOI: 10.1111/RESP.13211
Publisher: BMJ
Date: 18-11-2016
Publisher: American Thoracic Society
Date: 03-2011
Publisher: Elsevier BV
Date: 04-2002
Publisher: Springer International Publishing
Date: 2019
Publisher: Cold Spring Harbor Laboratory
Date: 08-07-2023
DOI: 10.1101/2023.07.07.23292251
Abstract: Sleep is essential to life. Accurate measurement and classification of sleep/wake and sleep stages is important in clinical studies for sleep disorder diagnoses and in the interpretation of data from consumer devices for monitoring physical and mental well-being. Existing non-polysomnography sleep classification techniques mainly rely on heuristic methods developed in relatively small cohorts. Thus, we aimed to establish the accuracy of wrist-worn accelerometers for sleep stage classification and subsequently describe the association between sleep duration and efficiency (proportion of total time asleep when in bed) with mortality outcomes. We developed and validated a self-supervised deep neural network for sleep stage classification using concurrent laboratory-based polysomnography and accelerometry data from three countries (Australia, the UK, and the USA). The model was validated within-cohort using subject-wise five-fold cross-validation for sleep-wake classification and in a three-class setting for sleep stage classification wake, rapid-eye-movement sleep (REM), non-rapid-eye-movement sleep (NREM) and by external validation. We assessed the face validity of our model for population inference by applying the model to the UK Biobank with 100,000 participants, each of whom wore a wristband for up to seven days. The derived sleep parameters were used in a Cox regression model to study the association of sleep duration and sleep efficiency with all-cause mortality. After exclusion, 1,448 participant nights of data were used to train the sleep classifier. The difference between polysomnography and the model classifications on the external validation was 34.7 minutes (95% limits of agreement (LoA): −37.8 to 107.2 minutes) for total sleep duration, 2.6 minutes for REM duration (95% LoA: −68.4 to 73.4 minutes) and 32.1 minutes (95% LoA: −54.4 to 118.5 minutes) for NREM duration. The derived sleep architecture estimate in the UK Biobank s le showed good face validity. Among 66,214 UK Biobank participants, 1,642 mortality events were observed. Short sleepers ( hours) had a higher risk of mortality compared to participants with normal sleep duration (6 to 7.9 hours), regardless of whether they had low sleep efficiency (Hazard ratios (HRs): 1.69 95% confidence intervals (CIs): 1.28 to 2.24) or high sleep efficiency (HRs: 1.42 95% CIs: 1.14 to 1.77). Deep-learning-based sleep classification using accelerometers has a fair to moderate agreement with polysomnography. Our findings suggest that having short overnight sleep confers mortality risk irrespective of sleep continuity. This research has been conducted using the UK Biobank Resource under Application Number 59070. The UK Biobank received ethical approval from the National Health Service National Research Service (Ref 21/NW/0157). We would like to acknowledge the Raine Study participants and their families for their ongoing participation in the study and the Raine Study team for study coordination and data collection. We also thank the NHMRC for their long-term contribution to funding the study over the last 30 years. The core management of the Raine Study is funded by The University of Western Australia, Curtin University, Telethon Kids Institute, Women and Infants Research Foundation, Edith Cowan University, Murdoch University, The University of Notre Dame Australia and the Raine Medical Research Foundation. The 22-year Gen2 Raine Study follow-up was funded by NHMRC project grants 1027449 & 1044840. The data collection for the Pennsylvania dataset is funded, in part, by US National Institute of Health (NIMH) grant R21 MH103963 (MB). HY, DB, and AD are supported by Novo Nordisk. RW and AD are supported by Health Data Research UK, an initiative funded by UK Research and Innovation, Department of Health and Social Care (England) and the devolved administrations, and leading medical research charities. AD is additionally supported by Swiss Re, Wellcome Trust [223100/Z/21/Z], and the British Heart Foundation Centre of Research Excellence (grant number RE/18/3/34214). DWR is supported by MRC programme grant MR/P023576/1 Wellcome Trust (107849/Z/15/Z). TP and AR are supported by the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre and NIHR Applied Research Collaboration East Midlands (ARC EM). SDK is supported by the NIHR Oxford Health Biomedical Research Centre, Health Technology Assessment Programme, Efficacy and Mechanisms Evaluation Programme, Programme Grants for Applied Research, and the Wellcome Trust. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Computational aspects of this research were funded from the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC) with additional support from Health Data Research (HDR) UK and the Wellcome Trust Core Award [grant number 203141/Z/16/Z]. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. For the purpose of open access, the author has applied a CC-BY public copyright licence to any author accepted manuscript version arising from this submission. Sleep plays a crucial role in our mental and physical health. Nonetheless, much of our understanding of sleep relies on self-report sleep questionnaires, which are subject to recall bias. We searched on Web of Science, Medline, and Google Scholar from the database inception to June 23, 2023, using terms that included “wearable”, “actigraphy” or “accelerometer” in combination with “sleep stage” or “sleep classification”, and “polysomnography”. Existing studies have attempted to use machine learning to predict both sleep and sleep stages using accelerometry. However, prior methods were validated in populations of small s le sizes (n ), making the prediction validity unclear. To date, no study has examined variations of accelerometer-derived sleep stage estimates in large population datasets with longitudinal disease outcomes. We showed that our deep-learning-based method improves sleep staging for wrist-worn accelerometers against the current state-of-the-art. We quantified the model uncertainty in a large multicentre dataset with 1,448 nights of concurrent raw accelerometry and polysomnography recordings. We further demonstrated that our sleep staging method could capture population differences concerning age, season, and other sociodemographic characteristics using a large health database. Shorter overnight sleep duration was associated with an increased risk of all-cause mortality after seven years of follow-up in groups with both low and high sleep efficiencies. This study helps clinicians to interpret sleep measurements from wearable sensors in routine care. Researchers can use derived sleep parameters in large-scale accelerometer datasets to advance our understanding of the association between sleep and population subgroups with different clinical characteristics. Our findings further suggest that having a short overnight sleep is a risky behaviour regardless of the sleep quality, which requires immediate public attention to fight the social stigma that having a short sleep is acceptable as long as one sleeps well.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2015
DOI: 10.1007/S11325-014-1000-2
Abstract: Obstructive sleep apnea (OSA) is a common disorder that is associated with impaired attention, memory and executive function. However, the mechanisms underlying such dysfunction are unclear. To determine the influence of sleep fragmentation and hypoxia, this study examined the effect of sleep fragmentation and hypoxia on cognition in OSA, while controlling for potentially confounding variables including sleepiness, age and premorbid intelligence. Participants with and without OSA (N = 150) were recruited from the general community and a tertiary hospital sleep clinic. All underwent comprehensive, laboratory-based polysomnography (PSG) and completed assessments of cognition including attention, short- and long-term memory and executive function. Structural equation modelling (SEM) was used to construct a theoretically-driven model to examine the relationships between hypoxia and sleep fragmentation, and cognitive function. Although after controlling for IQ, increased sleep disturbance was a significant predictor of decreased attention (p = 0.04) and decreased executive function (p = 0.05), controlling for age removes these significant relationships. No significant predictors of memory function were found. The mechanisms underlying the effects of OSA on cognition remain to be defined. Implications are discussed in light of these findings.
Publisher: Wiley
Date: 28-11-2020
DOI: 10.1111/JSR.12958
Abstract: Obstructive sleep apnea (OSA) is a widely prevalent disorder that can affect cognitive function. The relationship between cognitive function and OSA is known to be affected by an in idual's premorbid cognitive ability. Tools to measure premorbid intelligence across OSA disease severity have not been validated. This brief report aims to establish if the National Adult Reading Test (NART) provides a stable estimate of premorbid intelligence across levels of OSA disease severity. We examined if NART scores varied systematically across levels of untreated OSA severity (defined according to the apnea-hypopnea index [AHI]) and mean oxygen saturation in sleep clinic (n = 121) and community s les (n = 398) using regression analysis. Simple linear regression was used to predict NART scores based on the AHI. NART-estimated premorbid IQ scores without demographics did not vary systematically with AHI (F < 1 β = 0.01) or mean SpO
Publisher: BMJ
Date: 12-02-2009
Abstract: Sleep hypoventilation has been proposed as a cause of progressive hypercapnic respiratory failure and death in patients with severe chronic obstructive pulmonary disease (COPD). A study was undertaken to determine the effects of nocturnal non-invasive bi-level pressure support ventilation (NIV) on survival, lung function and quality of life in patients with severe hypercapnic COPD. A multicentre, open-label, randomised controlled trial of NIV plus long-term oxygen therapy (LTOT) versus LTOT alone was performed in four Australian University Hospital sleep/respiratory medicine departments in patients with severe stable smoking-related COPD (forced expiratory volume in 1 s (FEV1.0) <1.5 litres or <50% predicted and ratio of FEV1.0 to forced vital capacity (FVC) 46 mm Hg and on LTOT for at least 3 months) and age 20/h) or morbid obesity (body mass index >40) were excluded. Outcome measures were survival, spirometry, arterial blood gases, polysomnography, general and disease-specific quality of life and mood. 144 patients were randomised (72 to NIV + LTOT and 72 to LTOT alone). NIV improved sleep quality and sleep-related hypercapnia acutely, and patients complied well with therapy (mean (SD) nightly use 4.5 (3.2) h). Compared with LTOT alone, NIV (mean follow-up 2.21 years, range 0.01-5.59) showed an improvement in survival with the adjusted but not the unadjusted Cox model (adjusted hazard ratio (HR) 0.63, 95% CI 0.40 to 0.99, p = 0.045 unadjusted HR 0.82, 95% CI 0.53 to 1.25, p = NS). FEV1.0 and PaCO2 measured at 6 and 12 months were not different between groups. Patients assigned to NIV + LTOT had reduced general and mental health and vigour. Nocturnal NIV in stable oxygen-dependent patients with hypercapnic COPD may improve survival, but this appears to be at the cost of worsening quality of life. ACTRN12605000205639.
Publisher: Wiley
Date: 04-1999
Publisher: Informa UK Limited
Date: 16-07-2016
DOI: 10.1080/08869634.2016.1206701
Abstract: Most in iduals with OSA remain undiagnosed, mainly due to limited access to effective screening tools and diagnostic facilities. Therefore, the objective of this study was to identify craniofacial and anthropometric measurements that predict OSA in an Indian population. Male subjects (n = 76) between 25 and 50 years of age were recruited for the study from the general population. The study measures consisted of home-based type IV polysomnography and a total of 40 anthropometric and craniofacial measurements. Key measures were identified, and a model was developed with these variables, which predicted the presence of OSA with a sensitivity, specificity and overall accuracy of 93.1, 20.0 and 74.4%, respectively. This preliminary study shows the utility of craniofacial and anthropometric variables in the identification of in iduals at risk of OSA. These findings need to be further validated against the results of overnight polysomnography in a large independent population.
Publisher: Wiley
Date: 2006
DOI: 10.1111/J.1440-1843.2006.00781.X
Abstract: The purpose of this study was to determine if the respiratory muscles of patients with COPD could be made to function anaerobically, as evidenced by an increase in arterial blood lactate concentration ([lactate](a)) during specific loading of the inspiratory muscles and, if so, the effect of a programme of high-intensity inspiratory muscle training on this function. In seven patients with COPD (FEV(1) = 33 +/- 14% of predicted), measurements of [lactate](a) were made each minute during progressive inspiratory threshold loading to voluntary exhaustion. These tests were performed before and after an 8-week programme of specific high-intensity inspiratory muscle training, combined with general whole-body exercise training. During inspiratory muscle loading small increases in [lactate](a) (0.83 +/- 0.32 mM) were observed in two subjects before training, and in five subjects after training (0.69 +/- 0.57 mM). [Lactate](a) only increased when the inspiratory work rate exceeded 6.9 cm H(2)O L/min per kilogram of body weight, and when baseline maximum inspiratory pressure exceeded 65 cm H(2)O. The results of this study demonstrated that it is possible for COPD patients to increase inspiratory muscle work rate to a level requiring a major energy contribution from anaerobic glycolytic metabolism. This was only seen when inspiratory muscle strength and endurance were sufficient to allow it. Some patients who failed to demonstrate an increase in [lactate](a) at baseline did so after a programme of high-intensity inspiratory muscle training.
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.SLEEP.2006.08.016
Abstract: The pressures generated within the upper esophageal sphincter (P(UES)) and lower esophageal sphincter (P(LES)) reflect the integrity of these barriers to gastroesophageal and pharyngoesophageal reflux, respectively. This study sought to describe the effects of sleep, respiration and posture on the function of the UES and the LES and the pressure differentials developed across them. Ten healthy volunteers (7M, 3F: 38+/-10 yr) without a history of sleep-disordered breathing or reflux underwent overnight polysomnography with simultaneous measurement of P(LES) and P(UES) using a purpose-built sleeve device (Dentsleeve). Posture was recorded but not controlled. Subjects slept for 4.3+/-1.6h. Compared to waking values, both end-inspiratory and end-expiratory Pues were significantly less during slow wave sleep (SWS) (p<0.05). However, P(LES) was unaffected by sleep stage. During wakefulness and all stages of sleep, both P(UES) and P(LES) were greater at end-inspiration than end-expiration (p<0.05). Similar relationships were observed whether subjects were supine or in the lateral decubitus position. Sleep decreases the effectiveness of the UES to act as a barrier to pharyngoesophageal reflux, particularly during slow wave sleep (SWS). UES pressure varies with respiration, with minimal values observed during expiration. Hence, barrier function of the UES appears most impaired during SWS, in the expiratory phase of the respiratory cycle. The LES pressure and its barrier pressure also vary with respiration, being least during expiration. However, unlike the UES, the function of the LES was unaffected by sleep.
Publisher: European Respiratory Society (ERS)
Date: 19-08-2014
DOI: 10.1183/09031936.00078014
Abstract: This study was designed to determine the effect of ground-based walking training on health-related quality of life and exercise capacity in people with chronic obstructive pulmonary disease (COPD). People with COPD were randomised to either a walking group that received supervised, ground-based walking training two to three times a week for 8–10 weeks, or a control group that received usual medical care and did not participate in exercise training. 130 out of 143 participants (mean± sd age 69±8 years, forced expiratory volume in 1 s 43±15% predicted) completed the study. Compared to the control group, the walking group demonstrated greater improvements in the St George’s Respiratory Questionnaire total score (mean difference -6 points (95% CI -10– -2), p .003), Chronic Respiratory Disease Questionnaire total score (mean difference 7 points (95% CI 2–11), p .01) and endurance shuttle walk test time (mean difference 208 s (95% CI 104–313), p .001). This study shows that ground-based walking training is an effective training modality that improves quality of life and endurance exercise capacity in people with COPD.
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.RESP.2011.04.001
Abstract: The functional outcomes of respiratory muscle loading by chemical (e.g. hypercapnia), mechanical (i.e. external mechanical loading) or ventilatory (e.g. exercise) factors can be either positive, such as through an increase in pressure-generating capacity of the inspiratory muscles or detrimental, such as by fatigue. Neurophysiological responses to respiratory muscle loading can occur at one or more points along the pathway from motor cortex to muscle. This paper describes the respiratory pump and upper airway motoneuron responses to the imposition of acute loads including processes of pre-activation, respiratory reflexes, potentiation and fatigue. It also considers changes suggestive of adaptation to chronic loading either from specific respiratory muscle training programs or as part of disease processes such as chronic obstructive pulmonary disease or obstructive sleep apnoea.
Publisher: Wiley
Date: 05-1999
DOI: 10.1111/J.1469-7793.1999.0259Z.X
Abstract: 1. We utilized a chronically tracheostomized, unanaesthetized dog model to study the reflex effects on inspiratory motor output of low- litude, high-frequency pressure oscillations (HFPOs) applied to the isolated upper airway (UA) during stable non-rapid eye movement (NREM) sleep. 2. HFPOs (30 Hz and +/-2 to +/-4 cmH2O) were applied via a piston pump during eupnoea, inspiratory resistive loading and tracheal occlusion. 3. When applied to the patent UA during expiration, and especially during late expiration, HFPOs prolonged expiratory time (TE) and tonically activated the genioglossus muscle EMG. When applied to the patent UA during inspiration, HFPOs caused tonic activation of the genioglossus muscle EMG and inhibition of inspiratory motor output by either: (a) a shortening of inspiratory time (TI), as inspiration was terminated coincident with the onset of HFPOs or (b) a prolonged TI accompanied by a decreased rate of rise of diaphragm EMG and rate of fall of tracheal pressure. These effects of HFPOs were observed during eupnoea and inspiratory resistive loading, but were maximal during tracheal occlusion where the additional inhibitory effects of lung inflation reflexes were minimized. 4. During eupnoea, topical anaesthesia of the UA abolished the HFPO-induced prolongation of TE, suggesting that the response was mediated primarily by mechanoreceptors close to the mucosal surface whereas the TE-prolonging effects of a sustained square wave of negative pressure (range, -4.0 to -14.9 cmH2O) sufficient to close the airway were preserved following anaesthesia. 5. These results demonstrate that high-frequency, low- litude oscillatory pressure waves in the UA, similar to those found in snoring, produce reflex inhibition of inspiratory motor output. This reflex may help maintain UA patency by decreasing the collapsing pressure generated by the inspiratory pump muscles and transmitted to the UA.
Publisher: European Respiratory Society (ERS)
Date: 10-10-2019
DOI: 10.1183/13993003.01320-2019
Abstract: Hypoglossal nerve stimulation (HNS) decreases obstructive sleep apnoea (OSA) severity via genioglossus muscle activation and decreased upper airway collapsibility. This study assessed the safety and effectiveness at 6 months post-implantation of a novel device delivering bilateral HNS via a small implanted electrode activated by a unit worn externally, to treat OSA: the Genio™ system. This prospective, open-label, non-randomised, single-arm treatment study was conducted at eight centres in three countries (Australia, France and the UK). Primary outcomes were incidence of device-related serious adverse events and change in the apnoea–hypopnoea index (AHI). The secondary outcome was the change in the 4% oxygen desaturation index (ODI). Additional outcomes included measures of sleepiness, quality of life, snoring and device use. This trial was registered with ClinicalTrials.gov, number NCT03048604 . 22 out of 27 implanted participants (63% male, aged 55.9±12.0 years, body mass index (BMI) 27.4±3.0 kg·m −2 ) completed the protocol. At 6 months BMI was unchanged (p=0.85) AHI decreased from 23.7±12.2 to 12.9±10.1 events·h −1 , a mean change of 10.8 events·h −1 (p .001) and ODI decreased from 19.1±11.2 to 9.8±6.9 events·h −1 , a mean change of 9.3 events·h −1 (p .001). Daytime sleepiness (Epworth Sleepiness Scale p=0.01) and sleep-related quality of life (Functional Outcomes of Sleep Questionnaire-10 p=0.02) both improved significantly. The number of bed partners reporting loud, very intense snoring, or leaving the bedroom due to participant snoring decreased from 96% to 35%. 91% of participants reported device use days per week, and 77% reported use for h per night. No device-related serious adverse events occurred during the 6-month post-implantation period. Bilateral HNS using the Genio™ system reduces OSA severity and improves quality of life without device-related complications. The results are comparable with previously published HNS systems despite minimal implanted components and a simple stimulation algorithm.
Publisher: American Physiological Society
Date: 05-2007
Abstract: The lower esophageal sphincter (LES) is the primary barrier to gastroesophageal reflux. Reflux is associated with periods of LES relaxation, as occurs during swallowing. Continuous positive airway pressure (CPAP) has been shown to reduce reflux in in iduals with and without sleep apnea, by an unknown mechanism. The aim of this study was to determine the effect of CPAP on swallow-induced LES relaxation. Measurements were made in 10 healthy, awake, supine in iduals. Esophageal (Pes), LES (Ples), gastric (Pg), and barrier pressure to reflux (Pb = Ples − Pg) were recorded using a sleeve catheter during five swallows of 5 ml of water. This was repeated at four levels of CPAP (0, 5, 10, and 15 cmH 2 O). Pressures were measured during quiet breathing and during the LES relaxation associated with a swallow. Duration of LES relaxation was also recorded. During quiet breathing, CPAP significantly increased end-expiratory Pes, Ples, Pg, and Pb ( P 0.05). The increase in Pb was due to a disproportionate increase in Ples compared with Pg ( P 0.05). During a swallow, CPAP increased nadir Ples, Pg, and Pb and decreased the duration of LES relaxation (4.1 s with 0-cmH 2 O CPAP to 1.6 s on 15-cmH 2 O CPAP, P 0.001). Pb increased with CPAP by virtue of a disproportionate increase in Ples compared with Pg. This may be due to either reflex activation of LES smooth muscle, or nonspecific transmission of pressure to the LES. The findings suggest CPAP may make the LES less susceptible to reflux by increasing Pb and decreasing the duration of LES relaxation.
Publisher: Elsevier BV
Date: 09-2008
DOI: 10.1016/J.APMR.2008.01.020
Abstract: To develop a predictive equation to permit estimation of the maximum work rate (Wmax) achieved during an incremental cycle ergometry test from the measurement of 6-minute walk distance (6MWD) and its derivative, 6-minute walk work, which is the product of 6MWD and body weight. Cross-sectional observational study. Outpatient physiotherapy and pulmonary physiology clinics in a tertiary hospital. Patients (N=50 36 men) with chronic obstructive pulmonary disease (forced expiratory volume in 1 second [FEV(1)]=37%+/-11% of predicted). Not applicable. Measurements were obtained of 6MWD and Wmax achieved during a laboratory-based, symptom-limited incremental cycle ergometry test. Linear regression analyses were performed using 6MWD, height, weight, and FEV(1) and using 6-minute walk work, height, and FEV(1) to determine their contribution to Wmax and to develop predictive equations for estimating Wmax. The equations derived to estimate Wmax using 6MWD and 6-minute walk work, respectively, were as follows: Wmax (W)=(0.122 x 6MWD)+(72.683 x height [m])-117.109 (r(2)=.67, standard error of the estimate [SEE]=10.8W) and Wmax (W)=17.393+(1.442 x 6-minute walk work) (r(2)=.60, SEE=11.8W). Wmax can be estimated from equations based on measurements of 6MWD or 6-minute walk work. The estimate of Wmax derived from either equation may provide a basis on which to prescribe cycle ergometry training work rates that comply with the current guidelines for pulmonary rehabilitation.
Publisher: American Physiological Society
Date: 05-2003
DOI: 10.1152/JAPPLPHYSIOL.01017.2002
Abstract: Genioglossus (GG) electrical activity [measured by electromyogram (EMGgg)] is best measured by intramuscular electrodes however, the homogeneity of EMGgg is undefined. We investigated the relationships between EMGgg and the site from which activity was measured to determine whether and to what extent inhomogeneity in activity occurred. Eight healthy human volunteers underwent ultrasound to determine GG depth and width. Four pairs of electrodes were then inserted percutaneously into the left and right GG muscle, anteriorly and posteriorly. Additional configurations were obtained by connecting electrodes across the midline and along each muscle belly. EMGgg activity was simultaneously recorded from these 10 configurations at rest and during various respiratory maneuvers. Heterogeneous behavior of the GG was evidenced by 1) the variable presence of phasic EMGgg at rest, which was undetectable in two subjects but evident in 65% of configurations in six subjects and present in all configurations in all subjects during voluntary hyperventilation 2) a greater litude of EMGgg response to pharyngeal square-wave negative pressure in anterior than posterior configurations (14.1 ± 7.1 vs. 8.5 ± 5.1% of maximum, P 0.05) and 3) variable (linear and alinear) relationships between EMGgg and lingual force within and between subjects. We hypothesize that regional differences in density and type of muscle fiber are the most likely sources of heterogeneity in these responses.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2010
Publisher: Wiley
Date: 21-06-2013
DOI: 10.1111/RESP.12111
Publisher: Wiley
Date: 22-10-2008
DOI: 10.1111/J.1440-1843.2008.01368.X
Abstract: Gastroesophageal reflux (GOR) has been implicated in the pathogenesis of bronchiolitis obliterans syndrome (BOS), possibly due to pulmonary aspiration of refluxed acid. Risk of aspiration of gastric contents is increased during sleep due to decreased oesophageal clearance mechanisms and may be further increased by the presence of OSA. This study investigated the relationship between nocturnal GOR, OSA and BOS in a group of lung transplant patients. Fourteen lung transplant patients underwent overnight polysomnography with simultaneous dual oesophageal pH monitoring. Patients had an FEV(1) of 84 +/- 15% of their best post-transplant FEV(1). Six of the 14 patients were in various stages of BOS. The average proportion of time spent overnight with a pH of 5 events per hour). There were no relationships between severity of OSA or GOR and severity of BOS. Both nocturnal GOR and OSA were common in this group of patients but their occurrences were not related. Neither was there any relationship between the presence of nocturnal GOR or OSA and severity of BOS.
Publisher: European Respiratory Society (ERS)
Date: 18-06-2010
Publisher: American Thoracic Society
Date: 05-2011
DOI: 10.1164/AJRCCM-CONFERENCE.2011.183.1_MEETINGABSTRACTS.A2726
Publisher: Wiley
Date: 16-10-2016
DOI: 10.1111/RESP.12907
Publisher: Elsevier BV
Date: 04-2006
DOI: 10.1016/J.RMED.2005.08.003
Abstract: The six minute walk test (6MWT) is the most commonly used exercise test in pulmonary rehabilitation however, the paucity of six minute walk distance (6MWD) reference values from population-based s les limits data interpretation in patients. This study was undertaken to determine 6MWD in a population-based s le of healthy subjects and to identify predictors of 6MWD in this group. Seventy Caucasian subjects (33 males) aged 55-75 years performed three tests using a standardised protocol. 6MWD was defined as the greatest distance achieved from the three tests. Other measurements included height, leg length, weight, forced expiratory volume in 1s (FEV(1)), exhaled carbon monoxide and self-reported physical activity including habitual walking. The average 6MWD was 659+/-62 m (range 484-820 m). Males walked 59+/-13 m further than females (P<0.001). Height (r=0.54, P<0.01), weight (r=0.25, P<0.05) and FEV(1) (r=0.48, P<0.001) were significantly correlated with 6MWD. Forwards stepwise multiple regression showed height (R(2)=0.294) and FEV(1) (R(2) change=0.045) to be independent predictors of 6MWD (P<0.05), explaining 33.9% of the variance. 6MWD in this healthy population-based s le of males and females exceeds values previously reported. Height and FEV(1) were identified as significant independent predictors of 6MWD in this group.
Publisher: Wiley
Date: 02-1993
Abstract: Human parvovirus B19 cannot be cultured in standard cell lines and relatively little is known about the intracellular life-cycle of the virus. In this study, ultrastructural features of B19 infection were examined using haemopoietic cell suspension cultures derived from human fetal liver. Erythroblasts from infected cultures frequently contained crystalline arrays of both full and empty virus-like particles. The number and size of these arrays increased with the duration of culture, and their location changed from exclusively nuclear at 24 h post-infection to both nuclear and cytoplasmic at 3 days post-infection. Arrays were occasionally found in cytoplasmic protuberances which appeared to be pinching off from the cell. The location of the arrays corresponded to the distribution of viral capsid protein determined by immunolabelling at the light microscope level. Cells containing viral crystalline arrays also exhibited nucleolar degeneration, extreme margination of the nuclear heterochromatin, and cytoplasmic vacuolation. These features are typical of cells undergoing in idual programmed cell death or 'apoptosis'. The triggering of apoptosis in erythroid precursors by parvovirus B19 may help to explain the apparent lack of a strong inflammatory response to fetal B19 infection and may have implications for understanding the mechanisms of viral spread throughout the host.
Publisher: European Respiratory Society (ERS)
Date: 30-06-2009
DOI: 10.1183/09031936.00020408
Abstract: The ability to measure airway dimensions is important for clinicians, interventional bronchoscopists and researchers in order to accurately quantify structural abnormalities and track their changes over time or in response to treatment. Most quantitative airway measurements are based on X-ray computed tomography and, more recently, on multidetector computed tomography. Quantitative bronchoscopic techniques have also been developed, although these are less widely employed. Emerging techniques, including magnetic resonance imaging, endoscopic optical coherence tomography, endobronchial ultrasound and confocal endomicroscopy, provide new research tools with potential clinical applications. An understanding of issues related to the acquisition, processing and analysis of images, and how such issues impact on imaging the tracheobronchial tree, is essential in order to assess measurement accuracy and to make effective use of the newer methods. This article contributes to this understanding by providing a comprehensive review of current and emerging techniques for quantifying airway dimensions.
Publisher: BMJ
Date: 24-07-2014
Publisher: Elsevier BV
Date: 08-2007
DOI: 10.1016/J.JSAMS.2007.03.002
Abstract: This study examined the effect of interstate travel on sleep patterns and game performance of elite Australian Rules footballers. Nineteen members of a Western Australian-based Australian Football League team participated in the study during the 2004 season. Sleep was assessed on the night before home and away games by measuring sleep duration (SLD), sleep efficiency (SLE), wake time (WT) and number of wakings (NW) via actigraphy. Subjective sleep quality was assessed using a sleep rating (SR) scale. Baseline sleep measurements were obtained over four consecutive non-game nights. Game performance was assessed using a coach's rating (CR) scale and impact ranking (IR) and by player statistics including frequency of possessions (P) and frequency of possessions and team assists (PTA). Compared to baseline, SLD was greater on the nights before home and away games (by 48 and 39 min, respectively, p<0.05). Other sleep measures were unchanged. Sleep rating was poorer before away than home games (p<0.05). CR and IR were greater during home than away games (p<0.05). All other measures of performance were similar at home and away. These results show that prior interstate travel has minimal effect on sleep quality and game performance in elite footballers.
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.61_12619
Publisher: Oxford University Press (OUP)
Date: 10-2023
Publisher: Springer Science and Business Media LLC
Date: 24-03-2016
Publisher: S. Karger AG
Date: 22-05-2010
DOI: 10.1159/000315142
Abstract: i Background: /i Some in iduals with moderate/severe persistent asthma develop irreversible airway obstruction. These in iduals present with dyspnoea, exercise intolerance and impaired quality of life (QOL), all of which could potentially be alleviated with exercise training. i Objective: /i To investigate whether exercise training improves functional exercise capacity and QOL in middle-aged and older adults with fixed airway obstruction asthma (FAOA). i Methods: /i 35 subjects aged 67.8 ± 10.6 years, with FEV sub /sub 59 ± 16% of predicted, were randomised to a 6-week ‘intervention’ period of supervised exercise training (n = 20) or usual care (n = 15). This period was preceded by a 3-week run-in period during which asthma control was assessed weekly. Functional exercise capacity (6-min walk distance, 6MWD) and QOL (Asthma QOL Questionnaire, AQLQ) were measured before, immediately following and 3 months after the intervention period. i Results: /i 34 subjects (exercise group, n = 19, and control group, n = 15) completed the intervention period. Relative to the control group, the exercise group had greater improvements immediately following and 3 months after the intervention in the AQLQ symptom domain (0.61, p = 0.001, and 0.57 points per item, p = 0.005) and AQLQ activity limitation domain (0.43, p = 0.04, and 0.55 points per item, p = 0.04). 6MWD increased (36 ± 37 m, p 0.01) in the exercise group immediately following training and remained elevated (34 ± 45 m, p 0.01) at the 3-month follow-up. The magnitude of change in 6MWD between groups was not significant, despite no change in the control group. i Conclusions: /i Supervised exercise training improves symptoms and QOL in adults with FAOA.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Wiley
Date: 09-2006
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.28_12618
Publisher: American Thoracic Society
Date: 10-1998
DOI: 10.1164/AJRCCM.158.4.9803108
Abstract: Progressive threshold loading (PTL) is frequently used to assess inspiratory muscle endurance in health and disease. We and others have noted a systematic increase in endurance with the first few exposures to the task in subjects previously naïve to PTL, which may not be related to conditioning of the muscles themselves. The purpose of this study was to investigate the mechanisms responsible for this increased endurance by examining the ventilatory responses to 3 PTL tests, each > 24 h apart, in 18 healthy subjects. During PTL, threshold pressure (Pth) was increased by approximately 10% every 2 min until task failure. Subjects were allowed to adopt any breathing pattern. Respiratory muscle strength (maximal inspiratory pressure [PImax]) was unchanged over successive tests while maximal Pth (Pthmax) during PTL increased (69 +/- 17, 77 +/- 16, and 86 +/- 11% of PImax, respectively, p < 0.05) (mean +/- SD), indicating that the increased Pthmax could not be attributed to improved respiratory muscle strength. Breathing pattern changed with successive tests, so that for comparative loads inspiratory time (TI), respiratory frequency (f ), and duty cycle (TI/Ttot) decreased. This change in breathing pattern did not alter respiratory muscle efficiency (respiratory muscle V O2/work), which was similar in each test (2.4 +/- 2.2%), but perceived effort (Borg Score), which was maximal at task failure in each test, decreased at comparative loads with successive tests. Thus, Pthmax during initial tests appeared to be limited by discomfort rather than respiratory muscle function. These findings suggest that the increased Pthmax with successive tests is a consequence of differences in the breathing pattern adopted, reflecting neuropsychological rather than respiratory muscle conditioning. Measurements from PTL should only be used to assess respiratory muscle performance after allowing time for learning.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2019
DOI: 10.1097/ALN.0000000000002883
Abstract: Dexmedetomidine is a sedative promoted as having minimal impact on ventilatory drive or upper airway muscle activity. However, a trial recently demonstrated impaired ventilatory drive and induction of apneas in sedated volunteers. The present study measured upper airway collapsibility during dexmedetomidine sedation and related it to propofol. Twelve volunteers (seven female) entered this nonblinded, randomized crossover study. Upper airway collapsibility (pharyngeal critical pressure) was measured during low and moderate infusion rates of propofol or dexmedetomidine. A bolus dose was followed by low (0.5 μg · kg−1 · h−1 or 42 μg · kg−1 · min−1) and moderate (1.5 μg · kg−1 · h−1 or 83 μg · kg−1 · min−1) rates of infusion of dexmedetomidine and propofol, respectively. Complete data sets were obtained from nine volunteers (median age [range], 46 [23 to 66] yr body mass index, 25.4 [20.3 to 32.4] kg/m2). The Bispectral Index score at time of pharyngeal critical pressure measurements was 74 ± 10 and 65 ± 13 (mean difference, 9 95% CI, 3 to 16 P = 0.011) during low infusion rates versus 57 ± 16 and 39 ± 12 (mean difference, 18 95% CI, 8 to 28 P = 0.003) during moderate infusion rates of dexmedetomidine and propofol, respectively. A difference in pharyngeal critical pressure during sedation with dexmedetomidine or propofol could not be shown at either the low or moderate infusion rate. Median (interquartile range) pharyngeal critical pressure was −2.0 (less than −15 to 2.3) and 0.9 (less than −15 to 1.5) cm H2O (mean difference, 0.9 95% CI, −4.7 to 3.1) during low infusion rates (P = 0. 595) versus −0.3 (−9.2 to 1.4) and −0.6 (−7.7 to 1.3) cm H2O (mean difference, 0.0 95% CI, −2.1 to 2.1 P = 0.980) during moderate infusion of dexmedetomidine and propofol, respectively. A strong linear relationship between pharyngeal critical pressure during dexmedetomidine and propofol sedation was evident at low (r = 0.82 P = 0.007) and moderate (r = 0.90 P & 0.001) infusion rates. These observations suggest that dexmedetomidine sedation does not inherently protect against upper airway obstruction.
Publisher: Wiley
Date: 19-08-2013
DOI: 10.1111/APT.12445
Abstract: Gastro-oesophageal reflux disease (GERD) adversely impacts on sleep, but the mechanism remains unclear. To review the literature concerning gastro-oesophageal reflux during the sleep period, with particular reference to the sleep/awake state at reflux onset. Studies identified by systematic literature searches were assessed. Overall patterns of reflux during the sleep period show consistently that oesophageal acid clearance is slower, and reflux frequency and oesophageal acid exposure are higher in patients with GERD than in healthy in iduals. Of the 17 mechanistic studies identified by the searches, 15 reported that a minority of reflux episodes occurred during stable sleep, but the prevailing sleep state at the onset of reflux in these studies remains unclear owing to insufficient temporal resolution of recording or analysis methods. Two studies, in healthy in iduals and patients with GERD, analysed sleep and pH with adequate resolution for temporal alignment of sleep state and the onset of reflux: all 232 sleep period reflux episodes evaluated occurred during arousals from sleep lasting less than 15 s or during longer duration awakenings. Six mechanistic studies found that transient lower oesophageal sphincter relaxations were the most common mechanism of sleep period reflux. Contrary to the prevailing view, subjective impairment of sleep in GERD is unlikely to be due to the occurrence of reflux during stable sleep, but could result from slow clearance of acid reflux that occurs during arousals or awakenings from sleep. Definitive studies are needed on the sleep/awake state at reflux onset across the full GERD spectrum.
Publisher: Springer Science and Business Media LLC
Date: 15-04-2015
Publisher: Cambridge University Press (CUP)
Date: 29-07-2020
DOI: 10.1017/S1368980020001652
Abstract: To investigate the association between energy drink (ED) use and sleep-related disturbances in a population-based s le of young adults from the Raine Study. Analysis of cross-sectional data obtained from self-administered questionnaires to assess ED use and sleep disturbance (Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire (FOSQ-10) and the Pittsburgh Sleep Symptoms Questionnaire–Insomnia (PSSQ-I)). Regression modelling was used to estimate the effect of ED use on sleep disturbances. All models adjusted for various potential confounders. Western Australia. Males and females, aged 22 years, from Raine Study Gen2–22 year follow-up. Of the 1115 participants, 66 % were never/rare users (i.e. once/month) of ED, 17·0 % were occasional users (i.e. once/month to once/week) and 17 % were frequent users (≥once/week). Compared with females, a greater proportion of males used ED occasionally (19 % v . 15 %) or frequently (24 % v . 11 %). Among females, frequent ED users experienced significantly higher symptoms of daytime sleepiness (FOSQ-10: β = 0·93, 95 % CI 0·32, 1·54, P = 0·003) and were five times more likely to experience insomnia (PSSQ-I: OR = 5·10, 95 % CI 1·81, 14·35, P = 0·002) compared with never/rare users. No significant associations were observed in males for any sleep outcomes. We found a positive association between ED use and sleep disturbances in young adult females. Given the importance of sleep for overall health, and ever-increasing ED use, intervention strategies are needed to curb ED use in young adults, particularly females. Further research is needed to determine causation and elucidate reasons for gender-specific findings.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Jaypee Brothers Medical Publishing
Date: 2013
Publisher: Walter de Gruyter GmbH
Date: 2020
Abstract: Contemporary orthodontic and surgical treatment goals are primarily focussed on achieving optimal aesthetic soft tissue outcomes in three dimensions. It is important, therefore, to establish valid three-dimensional normative models to assist in clinical decision-making. Ideally, such models should be customised to a patient’s in idual facial proportions. The aim of this study was to establish the most pleasing computer generated 3D facial form using a community-based s le population. Three-dimensional facial surface data (3dMDface) were obtained from 375 young adult Caucasians (195 males and 180 females, all approximately 22 years old) without craniofacial anomalies, all of whom were participants in The Raine Study in Western Australia with participants from Generation 2. These data were used to generate seven faces that represented the variations in convexity distributed evenly around an average. The faces were subsequently rated by orthodontists, oral surgeons, plastic surgeons, dentists and laypeople for attractiveness. Age, sex and occupation did not influence the preference among the various faces. The average face was rated as the most attractive. For males, a slightly concave profile and for females a slightly convex profile was preferred. The present study suggested that orthodontic/surgical treatment of Caucasians should be directed towards achieving an average facial form.
Publisher: BMJ
Date: 08-2016
Publisher: Oxford University Press (OUP)
Date: 06-12-2019
DOI: 10.1093/SLEEP/ZSY243
Abstract: Longitudinal data on the course and relationship of concurrent psychopathology in youth are scarce but are of need for better practical patient care and prevention. This study explores the course of (and relationships over time) between sleep problems and concurrent dimensional difficulties relating to anxiety/depression, attention deficiency, and aggressive behaviors in childhood and adolescence. The latter three may jointly form a broad syndrome, the dysregulation profile. Young people from the Raine Study, a large community cohort s le (N = 1625) were followed from age 5 to 17 years. Developmental courses of sleep problems and its concurrent regulatory difficulties were estimated separately and jointly. The majority of adolescents reported low levels of problems and which appeared to be stable over time, while a small group (rates between 7.8% and 10.1%) reported enduring problematic developmental courses. Sleep problems and regulatory difficulties shared a strong association in their development over time (in idual's probabilities of having the same courses, i.e. low-low and high-high, were between 89.8% and 92.3%). Furthermore, having persistent sleep problems over time was associated with an increased risk of having regulatory difficulties by approximately 10 times, and vice versa. Findings from this study provide empirical evidence for a strong mutual association in the development of sleep problems and difficulties of dysregulation with emotion, cognition, and aggression. It may be suggested that a positive screening of one such psychopathological dimension should lead to a careful assessment, not only to reduce the problem in question but also to prevent the youth from further problems.
Publisher: European Respiratory Society (ERS)
Date: 20-02-2020
DOI: 10.1183/13993003.00980-2019
Abstract: Pathophysiology changes associated with pleural effusion, its drainage and factors governing symptom response are poorly understood. Our objective was to determine: 1) the effect of pleural effusion (and its drainage) on cardiorespiratory, functional and diaphragmatic parameters and 2) the proportion as well as characteristics of patients with breathlessness relief post-drainage. Prospectively enrolled patients with symptomatic pleural effusions were assessed at both pre-therapeutic drainage and at 24–36 h post-therapeutic drainage. 145 participants completed pre-drainage and post-drainage tests 93% had effusions ≥25% of hemithorax. The median volume drained was 1.68 L. Breathlessness scores improved post-drainage (mean visual analogue scale (VAS) score by 28.0±24 mm dyspnoea-12 (D12) score by 10.5±8.8 resting Borg score before 6-min walk test (6-MWT) by 0.6±1.7 all p .0001). The 6-min walk distance (6-MWD) increased by 29.7±73.5 m, p .0001. Improvements in vital signs and spirometry were modest (forced expiratory volume in 1 s (FEV 1 ) by 0.22 L, 95% CI 0.18–0.27 forced vital capacity (FVC) by 0.30 L, 95% CI 0.24–0.37). The ipsilateral hemi-diaphragm was flattened/everted in 50% of participants pre-drainage and 48% of participants exhibited paradoxical or no diaphragmatic movement. Post-drainage, hemi-diaphragm shape and movement were normal in 94% and 73% of participants, respectively. Drainage provided meaningful breathlessness relief (VAS score improved ≥14 mm) in 73% of participants irrespective of whether the lung expanded (mean difference 0.14, 95% CI 10.02–0.29 p=0.13). Multivariate analyses found that breathlessness relief was associated with significant breathlessness pre-drainage (odds ratio (OR) 5.83 per standard deviation ( sd ) decrease), baseline abnormal aralyzed aradoxical diaphragm movement (OR 4.37), benign aetiology (OR 3.39), higher pleural pH (OR per sd increase 1.92) and higher serum albumin level (OR per sd increase 1.73). Breathlessness and exercise tolerance improved in most patients with only a small mean improvement in spirometry and no change in oxygenation. Breathlessness improvement was similar in participants with and without trapped lung. Abnormal hemi-diaphragm shape and movement were independently associated with relief of breathlessness post-drainage.
Publisher: Wiley
Date: 27-12-2009
Publisher: Elsevier BV
Date: 02-1996
DOI: 10.1046/J.1432-0436.1996.5950321.X
Abstract: The present work describes the pattern of human intestinal proliferation in an immunodeficient murine xenograft model, which we have shown to closely mimic cell ision in normal paediatric gut. Cellular proliferation was measured using a double-label technique combining MIB-1 immunohistochemistry and [3H]thymidine autoradiography, to critically compare values for the tissue growth fraction (G1, G2, S- and M-phase cells) and DNA synthesizing (S-phase) cells in xenograft epithelium, lamina propria, muscularis externa and intraepithelial lymphocytes. The MIB-1 monoclonal antibody (which recognises the cell-cycle dependent nuclear antigen Ki-67) specifically labelled proliferating human cells within the xenografts and did not cross-react with iding murine cells. This was confirmed using ultrastructural in situ hybridisation with human- and mouse-specific DNA probes to identify the genetic origin of proliferating cells. In general, we found a good tissue correlation between MIB-1 and [3H]thymidine labelling, the only exception being an apparent dysregulation of Ki-67 antigen expression in regenerating xenograft epithelium. In developed xenograft intestine, the highest levels of proliferation were consistently recorded within the crypt epithelium, where 15.7%-26.7% of cells were actively cycling and S-phase occupied approximately half of the cell cycle. The frequency distribution of proliferating epithelial cells within small and large intestinal xenograft crypts was clearly tissue-specific, showing typical patterns of cell ision. Therefore, the presence of functional pluripotent epithelial stem cells and conventional spatio-temporal patterns in cellular proliferation, migration, de-cycling, lineage commitment and cytodifferentiation now makes this an attractive experimental model with which to study human intestinal crypt responses to various types of tissue manipulation, e.g. cytotoxic, radiotherapeutic, dietary, endocrine and gene-targeting therapy.
Publisher: Wiley
Date: 05-12-2020
DOI: 10.1111/BJOP.12436
Abstract: Reports linking prenatal testosterone exposure to autistic traits and to a masculinized face structure have motivated research investigating whether autism is associated with facial masculinization. This association has been reported with greater consistency for females than for males, in studies comparing groups with high and low levels of autistic traits. In the present study, we conducted two experiments to examine facial masculinity/femininity in 151 neurotypical adults selected for either low, mid-range, or high levels of autistic traits. In the first experiment, their three-dimensional facial photographs were subjectively rated by 41 raters for masculinity/femininity and were objectively analysed. In the second experiment, we generated 6-face composite images, which were rated by another 36 raters. Across both experiments, findings were consistent for ratings of photographs and composite images. For females, a linear relationship was observed where femininity ratings decreased as a function of higher levels of autistic traits. For males, we found a U-shaped function where males with mid-range levels of traits were rated lowest on masculinity. Objective facial analyses revealed that higher levels of autistic traits were associated with less feminine facial structures in females and less masculine structures in males. These results suggest sex-specific relationships between autistic traits and facial masculinity/femininity.
Publisher: Springer Science and Business Media LLC
Date: 14-08-2011
DOI: 10.1007/S11325-010-0404-X
Abstract: Obstructive sleep apnea (OSA) is associated with increased nocturnal gastroesophageal reflux (nocturnal GER) events and symptoms. Treatment of OSA with continuous positive airway pressure (CPAP) reduces nocturnal GER in patients with OSA. This study sought to determine the: (1) relationship of nocturnal GER events with apnea/hypopnea and arousal, (2) effect of upper airway obstruction on the barrier function of the lower esophageal sphincter (LES), (3) mechanism of LES failure for each nocturnal GER event and (4) effect of CPAP on LES function during sleep. Eight patients with OSA and nocturnal GER underwent polysomnography with esophageal manometry and pH monitoring. The first half of the night was spent without CPAP and the second half with 10 cmH(2)O CPAP. Baseline LES barrier pressure (P (b)) was low in these patients. When patients were off CPAP, there were 2.7 ± 1.8 nocturnal GER events per hour and 70 ± 39 obstructive respiratory events per hour. There was no direct relationship between the occurrence of GER and obstructive events. While upper airway obstruction did not alter P (b), CPAP tended to increase the nadir P (b) during LES relaxation (LESR) and decreased the duration of LESR. Upper airway obstructive and nocturnal GER events are not directly related. The relatively low P (b) in these OSA patients raises the possibility of weakening of the gastroesophageal junction from repetitive strain associated with obstructed breathing events. The favourable effect of CPAP on nocturnal GER is possibly due to an increase in nadir P (b) and decrease in the duration for which the LES relaxes during swallow-induced and transient LESR.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
Publisher: American Physiological Society
Date: 07-2003
DOI: 10.1152/JAPPLPHYSIOL.01198.2002
Abstract: Upper airway (UA) patency may be influenced by surface tension (γ) operating within the (UAL). We examined the role of γ of UAL in the maintenance of UA patency in eight isoflurane-anesthetized supine human subjects breathing via a nasal mask connected to a pneumotachograph attached to a pressure delivery system. We evaluated 1) mask pressure at which the UA closed (Pcrit), 2) UA resistance upstream from the site of UA collapse (RUS), and 3) mask pressure at which the UA reopened (Po). A multiple pressure-transducer catheter was used to identify the site of airway closure (velopharyngeal in all subjects). UAL s les (0.2 μl) were collected, and the γ of UAL was determined by using the “pull-off force” technique. Studies were performed before and after the intrapharyngeal instillation of 5 ml of exogenous surfactant (Exosurf, Glaxo Smith Kline). The γ of UAL decreased from 61.9 ± 4.1 (control) to 50.3 ± 5.0 mN/m (surfactant P 0.02). Changes in Po, RUS, and Po - Pcrit (change = control - surfactant) were positively correlated with changes in γ ( r 2 0.6 P 0.02) but not with changes in Pcrit ( r 2 = 0.4 P 0.9). In addition, mean peak inspiratory airflow (no flow limitation) significantly increased ( P 0.04) from 0.31 ± 0.06 (control) to 0.36 ± 0.06 l/s (surfactant). These findings suggest that γ of UAL exerts a force on the UA wall that hinders airway opening. Instillation of exogenous surfactant into the UA lowers the γ of UAL, thus increasing UA patency and augmenting reopening of the collapsed airway.
Publisher: Wiley
Date: 04-09-2014
DOI: 10.1111/RESP.12374
Publisher: Wiley
Date: 14-09-2014
DOI: 10.1111/RESP.12376
Abstract: Conditions that increase load on respiratory muscles and/or reduce their capacity to cope with this load predispose to type 2 (hypercapnic) respiratory failure. In its milder forms, this imbalance between load and capacity may primarily manifest as sleep hypoventilation which, if untreated, can increase the likelihood of wakeful respiratory failure. Such problems are commonly seen in progressive respiratory neuromuscular disorders, morbid obesity and chronic obstructive pulmonary disease, either separately or together. Identifying patients at risk can be important in determining whether and when to intervene with treatments such as non-invasive ventilatory assistance. Measurements of wakeful respiratory function are fundamental to this risk assessment. These issues are reviewed in this paper.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2012
Publisher: Elsevier BV
Date: 08-2023
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-02-2020
DOI: 10.5664/JCSM.8190
Publisher: American Thoracic Society
Date: 15-01-2006
Publisher: Oxford University Press (OUP)
Date: 04-2010
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2002
DOI: 10.1097/00000542-200210000-00007
Abstract: The unprotected upper airway tends to obstruct during general anesthesia, yet its mechanical properties have not been studied in detail during this condition. To study its collapsibility, pressure-flow relationships of the upper airway were obtained at three levels of anesthesia (end-tidal isoflurane = 1.2%, 0.8%, and 0.4%) in 16 subjects while supine and spontaneously breathing on nasal continuous positive airway pressure. At each level of anesthesia, mask pressure was transiently reduced from a pressure sufficient to abolish inspiratory flow limitation (11.8 +/- 2.7 cm H(2)O) to pressures resulting in variable degrees of flow limitation. The relation between mask pressure and maximal inspiratory flow was determined, and the critical pressure at which the airway occluded was recorded. The site of collapse was determined from simultaneous measurements of nasopharyngeal, oropharyngeal, and hypopharyngeal and esophageal pressures. The airway remained hypotonic (minimal or absent intramuscular genioglossus electromyogram activity) throughout each study. During flow-limited breaths, inspiratory flow decreased linearly with decreasing mask pressure (r(2) = 0.86 +/- 0.17), consistent with Starling resistor behavior. At end-tidal isoflurane of 1.2%, critical pressure was 1.1 +/- 3.5 cm H O at 0.4% it decreased to -0.2 +/- 3.6 cm H(2)O ( & 0.05), indicating decreased airway collapsibility. This decrease was associated with a decrease in end-expiratory esophageal pressure of 0.6 +/- 0.9 cm H(2)O ( & 0.05), suggesting an increased lung volume. Collapse occurred in the retropalatal region in 14 subjects and in the retrolingual region in 2 subjects, and did not change with anesthetic depth. Isoflurane anesthesia is associated with decreased muscle activity and increased collapsibility of the upper airway. In this state it adopts the behavior of a Starling resistor. The decreased collapsibility observed with decreasing anesthetic depth was not a consequence of neuromuscular activity, which was unchanged. Rather, it may be related to increased lung volume and its effect on airway wall longitudinal tension. The predominant site of collapse is the soft palate.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2010
Publisher: Elsevier BV
Date: 04-2023
Publisher: American Diabetes Association
Date: 08-2004
DOI: 10.2337/DIABETES.53.8.2073
Abstract: Type 2 diabetes is associated with vascular dysfunction, accelerated atherosclerotic morbidity, and mortality. Abnormal vasomotor responses to chemoreflex activation may contribute to the acceleration of atherosclerotic diabetes complications, but these responses have not previously been investigated. We measured forearm mean blood flow (MBF) and mean vascular conductance (MVC) responses to isocapnic hypoxia in seven healthy and eight type 2 diabetic subjects during local intra-arterial saline infusion and α-adrenergic blockade (phentolamine). The effects of hypoxia on saline and phentolamine responses significantly differed between groups relative to normoxia, the %ΔMVC with hypoxia during saline was −3.3 ± 11.2% in control and 24.8 ± 13.3% in diabetic subjects, whereas phentolamine increased hypoxic %ΔMVC to similar levels (39.4 ± 9.7% in control subjects and 48.0 ± 11.8% in diabetic subjects, P & 0.05, two-way ANOVA). Absolute normoxic MBF responses during saline infusion were 91.9 ± 21.1 and 77.9 ± 15.3 in control and diabetic subjects, respectively, and phentolamine increased normoxic MBF to similar levels (165.2 ± 40.1 ml/min in control subjects and 175.9 ± 32.0 ml/min in diabetic subjects both P & 0.05). These data indicate that diabetic and control subjects exhibit similar responses to hypoxia in the presence of α-adrenergic blockade despite evidence of exaggerated α-mediated vasoconstriction at rest.
Publisher: Wiley
Date: 05-2012
DOI: 10.1111/J.1445-5994.2012.02771.X
Abstract: The influence of body composition and peripheral muscle strength on 6-minute walk distance was assessed by performing dual energy X-ray absorptiometry scanning, spirometry and dynamometry testing in 13 men and 13 women with severe chronic obstructive pulmonary disease. Multivariate modelling showed that 76% of the variance in 6-minute walk distance could be explained by an equation incorporating lung function, quadriceps strength and lean leg mass. These findings indicate an important role for lower limb strength measures in pulmonary rehabilitation training programmes.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-06-2013
DOI: 10.5664/JCSM.2776
Publisher: Informa UK Limited
Date: 07-02-2023
DOI: 10.1080/17461391.2021.2023659
Abstract: To investigate: (1) whether TV watching habits throughout childhood and adolescence, a proxy of sedentary behaviour, impacted cardiorespiratory fitness (CRF) in adulthood, and (2) whether any potential impact of TV watching in childhood and adolescence on CRF in adulthood was changed by adult physical activity (PA) levels. A longitudinal study with questionnaire data available regarding TV watching collected at ages 5, 8, 10, 14, 17 and 20 yrs, allowed trajectories of TV watching to be developed. At age 28 yrs, participants completed a V̇O
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Peter Eastwood.