ORCID Profile
0000-0001-9626-7460
Current Organisations
Austin Health
,
University of Southampton
,
Institute for Breathing and Sleep
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Publisher: Springer Science and Business Media LLC
Date: 04-03-2020
DOI: 10.1007/S41105-020-00259-9
Abstract: The aim of this document was to provide a commentary on the AASM Manual for Scoring of Sleep and Associated Events in an Australasian context. A panel of Australasian sleep professionals developed the commentary. Each member was tasked with reviewing an assigned section and reporting back with potential AASM Manual clarifications and alterations. These suggestions were evaluated by the panel and ultimately resulted in the recommendations in this document. The panel recognised that the AASM manual significantly advanced the standardisation of polysomnography recording, analysis, and reporting however, there were sections of the AASM Manual where the panel determined there were clarifications, additions, or alterations required. Some of the key panel recommendations included: (1) advice to exclude arousals in awake epochs in the arousal index, (2) recommendation of a single hypopnoea definition, as well as single options for EEG and EOG placements, (3) a minimum duration for the central and mixed components of a mixed apnoea, (4) the addition of a baseline definition for scoring respiratory events, (5) the addition of criteria for defining oxygen desaturation, and (6) advice change so that the scoring and reporting of respiratory effort-related arousals (RERAs) and snoring is ‘recommended’ rather than ‘optional’. While it is anticipated that the recommendations will improve standardisation across Australasian sleep services many of the recommendations are also relevant in a global setting and should be considered for inclusion in future updates of the AASM Manual.
Publisher: The Royal Society
Date: 10-07-2019
Abstract: There is strong evidence that humans can make rough estimates of the numerosity of a set of items, almost from birth. However, as numerosity covaries with many non-numerical variables, the idea of a direct number sense has been challenged. Here we applied two different psychophysical paradigms to demonstrate the spontaneous perception of numerosity in a cohort of young pre-school children. The results of both tasks showed that even at that early developmental stage, humans spontaneously base the perceptual choice on numerosity, rather than on area or density. Precision in one of these tasks predicted mathematical abilities. The results reinforce strongly the idea of a primary number sense and provide further evidence linking mathematical skills to the sensory precision of the spontaneous number sense, rather than to mechanisms involved in handling explicit numerosity judgements or extensive exposure to mathematical teaching.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 13-06-2019
DOI: 10.1167/19.6.14
Abstract: Humans can estimate and encode numerosity over a large range, from very few items to several hundreds. Two distinct mechanisms have been proposed: subitizing, for numbers up to four and estimation for larger numerosities. We have recently extended this idea by suggesting that for very densely packed arrays, when items are less segregable, a third "texture" mechanism comes into play. In this study, we provide further evidence for the existence of a third regime for numerosity. Reaction times were very low in the subitizing range, rising rapidly for numerosities greater than four. However, for tightly packed displays of very high numerosities, reaction times became faster. These results reinforce the idea of three regimes in the processing of numerosity, subitizing, estimation, and texture.
Publisher: Informa UK Limited
Date: 10-03-2006
Publisher: Oxford University Press (OUP)
Date: 03-2012
DOI: 10.5665/SLEEP.1710
Publisher: BMJ
Date: 07-05-2018
DOI: 10.1136/THORAXJNL-2017-211131
Abstract: Obstructive sleep apnoea (OSA) is highly prevalent in people with spinal cord injury (SCI). Polysomnography (PSG) is the gold-standard diagnostic test for OSA, however PSG is expensive and frequently inaccessible, especially in SCI. A two-stage model, incorporating a questionnaire followed by oximetry, has been found to accurately detect moderate to severe OSA (MS-OSA) in a non-disabled primary care population. This study investigated the accuracy of the two-stage model in chronic tetraplegia using both the original model and a modified version for tetraplegia. An existing data set of 78 people with tetraplegia was used to modify the original two-stage model. Multivariable analysis identified significant risk factors for inclusion in a new tetraplegia-specific questionnaire. Receiver operating characteristic (ROC) curve analyses of the questionnaires and oximetry established thresholds for diagnosing MS-OSA. The accuracy of both models in diagnosing MS-OSA was prospectively evaluated in 100 participants with chronic tetraplegia across four international SCI units. Injury completeness, sleepiness, self-reported snoring and apnoeas were included in the modified questionnaire, which was highly predictive of MS-OSA (ROC area under the curve 0.87 (95% CI 0.79 to 0.95)). The 3% oxygen desaturation index was also highly predictive (0.93 (0.87–0.98)). The two-stage model with modified questionnaire had a sensitivity and specificity of 83% (66–93) and 88% (75–94) in the development group, and 77% (65–87) and 81% (68–90) in the validation group. Similar results were demonstrated with the original model. Implementation of this simple alternative to full PSG could substantially increase the detection of OSA in patients with tetraplegia and improve access to treatments. Results, ACTRN12615000896572 (The Australian and New Zealand Clinical Trials Registry) and pre-results, NCT02176928 (clinicaltrials.gov).
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 04-2023
Publisher: Springer Science and Business Media LLC
Date: 12-08-2019
Publisher: Springer Science and Business Media LLC
Date: 24-08-2016
DOI: 10.1038/NCOMMS12536
Abstract: Humans, including infants, and many other species have a capacity for rapid, nonverbal estimation of numerosity. However, the mechanisms for number perception are still not clear some maintain that the system calculates numerosity via density estimates—similar to those involved in texture—while others maintain that more direct, dedicated mechanisms are involved. Here we show that provided that items are not packed too densely, human subjects are far more sensitive to numerosity than to either density or area. In a two-dimensional space spanning density, area and numerosity, subjects spontaneously react with far greater sensitivity to changes in numerosity, than either area or density. Even in tasks where they were explicitly instructed to make density or area judgments, they responded spontaneously to number. We conclude, that humans extract number information, directly and spontaneously, via dedicated mechanisms.
Publisher: European Respiratory Society (ERS)
Date: 09-2022
DOI: 10.1183/13993003.00422-2022
Abstract: For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future.
Publisher: American Thoracic Society
Date: 13-09-2023
Publisher: Springer Science and Business Media LLC
Date: 09-01-2019
DOI: 10.1038/S41393-018-0229-1
Abstract: Descriptive study. To determine the effect of respiratory event rule-set changes on the apnoea hypopnoea index, and diagnostic and severity thresholds in people with acute and chronic spinal cord injury. Eleven acute spinal cord injury inpatient hospitals across Australia, New Zealand, Canada and England community dwelling chronic spinal cord injury patients in their own homes. Polysomnography of people with acute (n = 24) and chronic (n = 78) tetraplegia were reanalysed from 1999 American Academy of Sleep Medicine (AASM) respiratory scoring, to 2007 AASM 'alternative' and 2012 AASM respectively. Equivalent cut points for published 1999 AASM sleep disordered breathing severity ranges were calculated using receiver operator curves, and results presented alongside analyses from the able-bodied. In people with tetraplegia, shift from 1999 AASM to 2007 AASM 'alternative' resulted in a 22% lower apnoea hypopnoea index, and to 2012 AASM a 17% lower index. In people with tetraplegia, equivalent cut-points for 1999 AASM severities of 5,15 and 30 were calculated at 2.4, 8.1 and 16.3 for 2007 AASM 'alternative' and 3.2, 10.0 and 21.2 for 2012 AASM. Interpreting research, prevalence and clinical polysomnography results conducted over different periods requires knowledge of the relationship between different rule-sets, and appropriate thresholds for diagnosis of disease. This project was proudly supported by the Traffic Accident Commission (Program grant) and the National Health and Medical Research Council (PhD stipend 616605).
Publisher: Cambridge University Press (CUP)
Date: 2018
DOI: 10.1017/S0140525X18001395
Abstract: In the target article, Rahnev & Denison (R& D) use serial effects as an ex le of suboptimality. We show here that serial effects can be beneficial to perception, serving to reduce both error and response times in a near-optimal fashion. Furthermore, serial effects for stable attributes are positive, whereas those for changeable attributes are negative, demonstrating that they are engaged flexibly to optimize performance.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.CORTEX.2019.07.009
Abstract: Dyscalculia is often associated with poor numerosity sensitivity. However, it is not known whether the perceptual systems of dyscalculics have implicit access to the sensory noise of numerosity judgements, and whether their perceptual systems take the noise levels into account in optimizing their perception. We tackled this question by measuring central tendency and serial dependence with a numberline task on dyscalculics and math-typical preadolescents. Numerosity thresholds were also measured with a separate 2AFC discrimination task. Our data confirmed that dyscalculics had poorer numerosity sensitivity and less accurate numberline mapping. Importantly, numberline responses, as well as central tendency and serial dependence strengths, were well predicted by sensory thresholds and could be modelled by a performance-optimizing Bayesian model based on sensory thresholds, suggesting that the functional architecture of systems encoding numerosity in dyscalculia is preserved. We speculate that the numerosity system of dyscalculics has retained those perceptual strategies that are useful to cope with and compensate for low sensory resolution.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.RESP.2016.10.014
Abstract: Respiratory related evoked potentials (RREPs) were used to investigate whether sensory detection of small mid-inspiratory resistive loads (≈1.2-6.2 cmH
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.SLEEP.2014.11.005
Abstract: This study examined the impact of using two abbreviated signal montages on the accuracy, precision and inter-scorer reliability of polysomnography (PSG) sleep and arousal scoring, compared to a standard reference montage, in a cohort of patients investigated for obstructive sleep apnoea (OSA). One abbreviated montage incorporated two signals dedicated to sleep and arousal scoring, and the other incorporated a single signal. Four scorers from two laboratories each scored 15 PSGS four times in random order: once using each abbreviated montage and twice using the reference montage. Use of the two-signal montage resulted in small changes in the distribution of sleep stages, a reduction in the arousal index and resultant reductions in sleep and arousal scoring agreement. For the one-signal montage, although similar magnitude sleep stage distribution changes were observed, there were larger reductions in the arousal index, and sleep and arousal scoring accuracy. Additionally, using the one-signal montage, there were statistically significant reductions in the precision of summary statistics including total sleep time (TST) and the amount of rapid eye movement (REM) sleep scored, and reductions in the inter-scorer reliability of REM sleep and arousal scoring. These findings demonstrate that abbreviated signal montages may result in underestimation of the arousal index and, depending on the montage, poorer precision in TST and REM sleep scoring, with potential consequences for apnoea-hypopnoea index (AHI) measures and OSA diagnosis. The results highlight the importance of careful evaluation of PSG results when using portable devices that have restricted signals, and they offer guidance for future PSG and portable monitoring standards.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.RESP.2018.08.005
Abstract: Respiratory related evoked potentials (RREP) were used to examine respiratory stimulus gating. RREPs produced by consciously detected vs. undetected loads, near the detection threshold, were compared. Participants (n = 17) were instrumented with EEG and a nasal mask connected to a loading manifold, which presented a range of mid-inspiratory resistive loads, plus a control, in a random block design. Participants were cued prior to the stimulus and signalled detection by a button press. There were statistically significant differences in peak-to-peak litude of the P1 RREP peak for detected (mean ± SD 3.86 ± 1.45 μV P = 0.020) and undetected loads (3.67 ± 1.27 μV P = 0.002) vs. control (2.36 ± 0.81 μV), although baseline-to-peak differences were not significantly different. In contrast peak-to-peak P3 litude was significantly greater for detected (5.91 ± 1.54 μV P < 0.001) but not undetected loads (3.33 ± 0.98 μV P = 0.189) vs. control (3.69 ± 1.46 μV), with the same pattern observed for baseline-to-peak measurements. The P1 peak, thought to reflect arrival of somatosensory information, appeared to be present in response to both detected and undetected loads, but the later P3 peak, was present for detected loads only. This suggests that for sub-threshold loads sensory information may reach the cortex, arguing against a sub-cortical gating process.
Publisher: Zenodo
Date: 2021
Publisher: Oxford University Press (OUP)
Date: 02-2009
Publisher: American Academy of Sleep Medicine (AASM)
Date: 05-2022
DOI: 10.5664/JCSM.9878
Publisher: BMJ
Date: 11-12-2019
DOI: 10.1136/THORAXJNL-2018-212319
Abstract: Highly prevalent and severe sleep-disordered breathing caused by acute cervical spinal cord injury (quadriplegia) is associated with neurocognitive dysfunction and sleepiness and is likely to impair rehabilitation. To determine whether 3 months of autotitrating CPAP would improve neurocognitive function, sleepiness, quality of life, anxiety and depression more than usual care in acute quadriplegia. Multinational, randomised controlled trial (11 centres) from July 2009 to October 2015. The primary outcome was neurocognitive (attention and information processing as measure with the Paced Auditory Serial Addition Task). Daytime sleepiness (Karolinska Sleepiness Scale) was a priori identified as the most important secondary outcome. 1810 incident cases were screened. 332 underwent full, portable polysomnography, 273 of whom had an apnoea hypopnoea index greater than 10. 160 tolerated at least 4 hours of CPAP during a 3-day run-in and were randomised. 149 participants (134 men, age 46±34 years, 81±57 days postinjury) completed the trial. CPAP use averaged 2.9±2.3 hours per night with 21% fully ‘adherent’ (at least 4 hours use on 5 days per week). Intention-to-treat analyses revealed no significant differences between groups in the Paced Auditory Serial Addition Task (mean improvement of 2.28, 95% CI −7.09 to 11.6 p=0.63). Controlling for premorbid intelligence, age and obstructive sleep apnoea severity (group effect −1.15, 95% CI −10 to 7.7) did not alter this finding. Sleepiness was significantly improved by CPAP on intention-to-treat analysis (mean difference −1.26, 95% CI −2.2 to –0.32 p=0.01). CPAP did not improve Paced Auditory Serial Addition Task scores but significantly reduced sleepiness after acute quadriplegia. ACTRN12605000799651.
Publisher: Oxford University Press (OUP)
Date: 2011
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 07-12-2018
DOI: 10.1167/18.13.7
Publisher: American Physiological Society
Date: 12-2019
DOI: 10.1152/JAPPLPHYSIOL.00186.2019
Abstract: This study aimed to determine whether there is impairment of genioglossus neuromuscular responses to small negative pressure respiratory stimuli, close to the conscious detection threshold, in obstructive sleep apnea (OSA). We compared genioglossus electromyogram (EMGgg) responses to midinspiratory resistive loads of varying intensity (≈1.2–6.2 cmH 2 O·L −1 ·s), delivered via a nasal mask, between 16 severe OSA and 17 control participants while the subjects were awake and in a seated upright position. We examined the relationship between stimulus intensity and peak EMGgg litude in a 200-ms poststimulus window and hypothesized that OSA patients would have an increased activation threshold and reduced sensitivity in the relationship between EMGgg activation and stimulus intensity. There was no significant difference between control and OSA participants in the threshold ( P = 0.545) or the sensitivity ( P = 0.482) of the EMGgg litude vs. stimulus intensity relationship, where change in epiglottic pressure relative to background epiglottic pressure represented stimulus intensity. These results do not support the hypothesis that deficits in neuromuscular response to negative upper airway pressure exist in OSA during wakefulness however, the results are likely influenced by a counterintuitive and novel genioglossus muscle suppression response observed in a significant proportion of both OSA and healthy control participants. This suppression response may relate to the inhibition seen in inspiratory muscles such as the diaphragm in response to sudden-onset negative pressure, and its presence provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure. NEW & NOTEWORTHY Our study used a novel midinspiratory resistive load stimulus to study upper airway neuromuscular responses to negative pressure during wakefulness in obstructive sleep apnea (OSA). Although no differences were found between OSA and healthy groups, the study uncovered a novel and unexpected suppression of neuromuscular activity in a large proportion of both OSA and healthy participants. The unusual response provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 17-03-2020
DOI: 10.1167/JOVI.20.3.3
Publisher: Oxford University Press (OUP)
Date: 11-09-2023
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2018.10.006
Abstract: It has been suggested that a core deficit of the "number sense" may underlie dyscalculia. We test this idea by measuring perceptual adaptation and discrimination thresholds for numerosity and object size in a group of dyscalculic and typical preadolescents (N = 71, mean age 12). We confirmed that numerosity discrimination thresholds are higher in developmental dyscalculia, while size thresholds are not affected. However, dyscalculics adapted to numerosity in a similar way to typicals. This suggests that although numerosity thresholds are selectively higher in dyscalculia, the mechanisms for perceiving numerosity are otherwise similar, suggesting that have a similar, but perhaps noisier, number sense.
Publisher: The Royal Society
Date: 31-10-2018
Abstract: The world tends to be stable from moment to moment, leading to strong serial correlations in natural scenes. As similar stimuli usually require similar behavioural responses, it is highly likely that the brain has developed strategies to leverage these regularities. A good deal of recent psychophysical evidence is beginning to show that the brain is sensitive to serial correlations, causing strong drifts in observer responses towards previously seen stimuli. However, it is still not clear that this tendency leads to a functional advantage. Here, we test a formal model of optimal serial dependence and show that as predicted, serial dependence in an orientation reproduction task is dependent on current stimulus reliability, with less precise stimuli, such as low spatial frequency oblique Gabors, exhibiting the strongest effects. We also show that serial dependence depends on the similarity between two successive stimuli, again consistent with the behaviour of an ideal observer aiming at minimizing reproduction errors. Lastly, we show that serial dependence leads to faster response times, indicating that the benefits of serial integration go beyond reproduction error. Overall our data show that serial dependence has a beneficial role at various levels of perception, consistent with the idea that the brain exploits the temporal redundancy of the visual scene as an optimization strategy.
Publisher: American Academy of Sleep Medicine (AASM)
Date: 15-11-2016
DOI: 10.5664/JCSM.6272
Publisher: European Respiratory Society (ERS)
Date: 05-03-2020
DOI: 10.1183/13993003.01905-2019
Abstract: The recently published Global Lung Function Initiative (GLI) carbon monoxide transfer factor ( T LCO ) reference equations provide an opportunity to adopt a current, all-age, widely applicable reference set. The aim of this study was to document the effect of changing to GLI from commonly utilised reference equations on the interpretation of T LCO results. 33 863 T LCO results (48% female, 88% Caucasian, n=930 aged years) from clinical pulmonary function laboratories within three Australian teaching hospitals were analysed. The lower limit of normal (LLN) and proportion of patients with a T LCO below this value were calculated using GLI and other commonly used reference equations. The average T LCO LLN for GLI was similar or lower than the other equations, with the largest difference seen for C rapo equations (median: −1.25, IQR: −1.64, −0.86 mmol·min −1 ·kPa −1 ). These differences resulted in altered rates of reduced T LCO for GLI particularly for adults (+1.9% versus M iller to −27.6% versus C rapo ), more so than for children (−0.8% versus K im to −14.2% versus C otes ). For adults, the highest raw agreement for GLI was with M iller equations (94.7%), while for children it was with K im equations (98.1%). Results were reclassified from abnormal to normal more frequently for younger adults, and for adult females, particularly when moving from R oca to GLI equations (30% of females versus 16% of males). The adoption of GLI T LCO reference equations in adults will result in altered interpretation depending on the equations previously used and to a greater extent in adult females. The effect on interpretation in children is less significant.
Publisher: Wiley
Date: 25-04-2018
DOI: 10.1113/JP275222
Publisher: European Respiratory Society (ERS)
Date: 18-02-2021
Publisher: Public Library of Science (PLoS)
Date: 29-03-2022
DOI: 10.1371/JOURNAL.PONE.0266052
Abstract: Smoking and chronic obstructive pulmonary disease (COPD) are associated with an increased risk of post-operative pulmonary complications (PPCs) following lung cancer resection. It remains unclear whether smoking cessation reduces this risk. Retrospective review of a large, prospectively collected database of over 1000 consecutive resections for lung cancer in a quaternary lung cancer centre over a 23-year period. One thousand and thirteen patients underwent curative-intent lobectomy or pneumonectomy between 1995 and 2018. Three hundred and sixty-two patients (36%) were ex-smokers, 314 (31%) were current smokers and 111 (11%) were never smokers. A pre-operative diagnosis of COPD was present in 57% of current smokers, 57% of ex-smokers and 20% of never smokers. Just over 25% of patients experienced a PPC. PPCs were more frequent in current smokers compared to never smokers (27% vs 17%, p = 0.036), however, no difference was seen between current and ex-smokers (p = 0.412) or between never and ex-smokers (p = 0.113). Those with a diagnosis of COPD, independent of smoking status, had a higher frequency of both PPCs (65% vs 35%, p .01) and overall complications (60% vs 40%, p .01) as well as a longer length of hospital stay (10 vs 9 days, p .01). Smoking and COPD are both associated with a higher rate of PPCs post lung cancer resection. COPD, independent of smoking status, is also associated with an increased overall post-operative complication rate and length of hospital stay. An emphasis on COPD treatment optimisation, rather than smoking cessation in isolation, may help improve post-operative outcomes.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2023
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CORTEX.2018.11.019
Abstract: Animals including humans are endowed with a remarkable capacity to estimate rapidly the number of items in a scene. Some have questioned whether this ability reflects a genuine sense of number, or whether numerosity is derived indirectly from other covarying attributes, such as density and area. In previous work we have demonstrated that adult observers are more sensitive to changes in numerosity than to area or density, particularly changes that leave numerosity constant, pointing to a spontaneous sensitivity to numerosity, not attributable to area and density. Here we extend this line of research with a novel technique where participants reproduce the size and density of a dot-array. They were given no explicit instructions of what to match, but could regulate freely all combinations of area and density by trackpad. If the task is mediated by matching separately area and texture-density, the errors in the two attributes have to be independent. Contrarily to this prediction, we found that errors in area and density were negatively correlated, suggesting that subjects matched numerosity, rather than area and density. We employed this technique to investigate processing of number in adolescents with typical and low math abilities (dyscalculia). Interestingly, we found that dyscalculics also reproduced numerosity rather than area or density. However, compared to typicals, dyscalculics had longer reaction times, a tendency to rely also on area, and their performance did not improve over sessions. Taken together, the data demonstrate that numerosity emerges as the most spontaneous and sensitive dimension, supporting the existence of a dedicated number sense and confirm numerosity atypicalities in dyscalculia.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Warren Ruehland.