ORCID Profile
0000-0001-6316-2259
Current Organisation
University of South Australia
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Publisher: American Physiological Society
Date: 07-2019
Abstract: Corticospinal tract excitability can be altered by age, physical activity (PA), and possibly sex, but whether these effects differ between upper and lower limb muscles is unknown. We determined the influence of age, PA, and sex on corticospinal excitability of an upper limb and a lower limb muscle during submaximal contractions by comparing stimulus-response curves of motor evoked potentials (MEPs). Transcranial magnetic stimulation (TMS) was used to evoke stimulus-response curves in active muscles by incrementally increasing the stimulator intensity from below the active motor threshold (AMT) until a plateau in MEP litudes was achieved. Stimulus-response curves were analyzed from the first dorsal interosseous (FDI) of 30 young (23.9 ± 3.8 yr) and 33 older (72.6 ± 5.6 yr) men and women and the vastus lateralis (VL) of 13 young (23.2 ± 2.2 yr) and 25 older (72.7 ± 5.5 yr) men and women. Corticospinal excitability was determined by fitting the curves with a four-parameter sigmoidal curve and calculating the maximal slope (slope max ). PA was assessed with triaxial accelerometry, and participants were dichotomized into high-PA ( ,000 steps/day, n = 15) or low-PA ( ,000 steps/day, n = 43) groups. Young adults had larger FDI MEP litudes (% maximum litude of compound muscle action potential) at higher TMS intensities (120–150% AMT) and greater slope max than older adults ( P 0.05), with no differences between high- and low-PA groups ( P 0.05). VL MEP litudes and slope max , however, were lower in the high-PA than low-PA participants, with no age or sex differences. These data suggest that aging and PA, but not sex, differentially influence the excitability of the corticospinal tracts projecting to muscles of the upper compared with the lower limb. NEW & NOTEWORTHY Excitability of the corticospinal tract projecting to the first dorsal interosseous assessed with transcranial magnetic stimulation was reduced with age but independent of regular physical activity (steps/day) and sex of the in idual. In contrast, corticospinal excitability of the vastus lateralis was not affected by age but was reduced in in iduals achieving more than the physical activity recommendations of 10,000 steps/day. Aging and activity differentially affect corticospinal excitability of upper and lower limb muscles.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Cold Spring Harbor Laboratory
Date: 31-07-2021
DOI: 10.1101/2021.07.28.21261299
Abstract: Approximately 40% of late-life dementia may be prevented by addressing modifiable risk factors, including physical activity and diet. Yet, it is currently unknown how multiple lifestyle factors interact to influence cognition. The ACTIVate Study aims to 1) Explore associations between 24-hour time-use and diet compositions with changes in cognition and brain function and 2) Identify durations of time-use behaviours and the dietary compositions to optimise cognition and brain function. This three-year prospective longitudinal cohort study will recruit 448 adults aged 60-70 years across Adelaide and Newcastle, Australia. Time-use data will be collected through wrist-worn activity monitors and the Multimedia Activity Recall for Children and Adults (MARCA). Dietary intake will be assessed using the Australian Eating Survey food frequency questionnaire. The primary outcome will be cognitive function, assessed using the Addenbrooke’s Cognitive Examination-III (ACE-III). Secondary outcomes include structural and functional brain measures using Magnetic Resonance Imaging (MRI), cerebral arterial pulse measured with Diffuse Optical Tomography (Pulse-DOT), neuroplasticity using simultaneous Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG), and electrophysiological markers of cognitive control using event-related potential (ERP) and time-frequency analyses. Compositional data analysis, testing for interactions between time-point and compositions, will assess longitudinal associations between dependent (cognition, brain function) and independent (time-use and diet compositions) variables. The ACTIVate Study will be the first to examine associations between time-use and diet compositions, cognition and brain function. Our findings will inform new avenues for multidomain interventions that may more effectively account for the co-dependence between activity and diet behaviours for dementia prevention. Ethics approval has been obtained from University of South Australia’s Human Research Ethics committee (202639). Findings will be disseminated through peer reviewed manuscripts, conference presentations, targeted media releases and community engagement events. Australia New Zealand Clinical Trials Registry (ACTRN12619001659190). The ACTIVate Study will collect comprehensive measures of lifestyle behaviours and dementia risk over time in 448 older adults aged 60-70 years. Using newly developed Compositional Data Analysis (CoDA) techniques we will examine the associations between time-use and diet compositions, cognition and brain function. Data will inform the development of a digital tool to help older adults obtain personalised information about how to reduce their risk of cognitive decline based on changes to time use and diet. Recruitment will be focussed on older adults to maximise the potential of making an impact on dementia prevention in the next 10 years. Findings may not be generalisable to younger adults.
Publisher: Springer Science and Business Media LLC
Date: 11-2022
DOI: 10.1186/S44167-022-00005-1
Abstract: How we spend our time and what we eat have important implications for our health. Evidence suggests that health-equivalent behaviour change options which result in the same benefit are available within both time use (physical activities, sedentary behaviours and sleep) and diet (e.g., fruit and vegetables, snack foods). However, it is not yet known if health-equivalent choices exist across both time-use and diet behaviours. This study aimed to explore if a variety of different time-use and dietary profiles were associated with equivalent physical functioning score among adolescents. This study used cross-sectional data from 2123 adolescent participants from the Longitudinal Study of Australian Children (LSAC) (mean age = 14.4 ± 0.5 years), including time-use diaries (min/day of sleep, self-care, screen time, quiet time, physical activity, school-related and domestic/social), diet questionnaires (serves/day of fruit and vegetables, discretionary (snack) foods and sugar-sweetened beverages) and a measure of physical functioning (PedsQL™ 4.0 physical functioning scale for teens). Multiple linear regression models were used to find the association of 24-h time-use composition (expressed as isometric log ratios) and dietary variables with physical functioning score. The models were used to estimate which time-use and diet profiles (within a feasible range from the s le average) were associated with equivalent physical functioning scores. Finally, an interactive app was developed to make the results accessible to end users. Within 30 min and 1.5 servings of the average adolescent’s time-use and dietary behaviours, 45 equivalent options were associated with a ~ 0.2 SD improvement in physical functioning scale. All options associated with this improvement in physical function involved increasing physical activity and increasing fruit and vegetable intake, whilst also reducing discretionary food intake and sugar-sweetened beverages. Most behavioural options also increased sleep and reduced time spent in self-care, screen time and quiet time activities. There are a range of time-use and diet profiles that may result in equivalent benefits in physical functioning among adolescents. Communicating these options using decision tools such as interactive apps may allow for tailored interventions across both time use and diet which are based on an in idual’s needs, preferences and constraints.
Publisher: Cold Spring Harbor Laboratory
Date: 16-05-2023
DOI: 10.1101/2023.05.15.23289982
Abstract: Increasing physical activity (PA) is an effective strategy to slow reductions in cortical volume and maintain cognitive function in older adulthood. However, PA does not exist in isolation, but coexists with sleep and sedentary behaviour to make up the 24-hour day. We investigated how the balance of all three behaviours (24-hour time-use composition) is associated with grey matter volume in healthy older adults, and whether grey matter volume influences the relationship between 24-hour time-use composition and cognitive function. This cross-sectional study included 378 older adults (65.6 ± 3.0 years old, 123 male) from the ACTIVate study across two Australian sites (Adelaide and Newcastle). Time-use composition was captured using 7-day accelerometry, and T1-weighted magnetic resonance imaging was used to measure grey matter volume both globally and across regions of interest (ROI: frontal lobe, temporal lobe, hippoc i, and lateral ventricles). Pairwise correlations were used to explore univariate associations between time-use variables, grey matter volumes and cognitive outcomes. Compositional data analysis linear regression models were used to quantify associations between ROI volumes and time-use composition, and explore potential associations between the interaction between ROI volumes and time-use composition with cognitive outcomes. After adjusting for covariates (age, sex, education), there were no significant associations between time-use composition and any volumetric outcomes. There were significant interactions between time-use composition and frontal lobe volume for long-term memory (p=0.018) and executive function (p=0.018), and between time-use composition and total grey matter volume for executive function (p=0.028). Spending more time in moderate-vigorous PA was associated with better long-term memory scores, but only for those with smaller frontal lobe volume (below the s le mean). Conversely, spending more time in sleep and less time in sedentary behaviour was associated with better executive function in those with smaller total grey matter volume. Although 24-hour time use was not associated with total or regional grey matter independently, total grey matter and frontal lobe grey matter volume mediated the relationship between time-use composition and several cognitive outcomes. Future studies should investigate these relationships longitudinally to assess whether changes in time-use composition correspond to changes in grey matter volume and cognition.
Publisher: Elsevier
Date: 2019
DOI: 10.1016/BS.PBR.2019.03.010
Abstract: An emerging literature is specifically focusing on the effects of sleep deprivation on aspects of social functioning and underlying neural changes. Two critical facets of social behavior emerge that are negatively impacted by sleep deprivation-self-regulation, which includes behavioral and emotional regulation, and social monitoring, which includes perceiving and interpreting cues relating to self and others. Sleep deprived in iduals performing tasks with social components show altered brain activity in areas of the prefrontal cortex implicated in self-control, inhibition, evaluation, and decision-making, in proximity to mesocorticolimbic pathways to reward and emotional processing areas. These cognitive changes lead to increased reward seeking and behaviors that promote negative health outcomes (such as increased consumption of indulgence foods). These changes also lead to emotional disinhibition and increased responses to negative stimuli, leading to reductions in trust, empathy, and humor. Concomitant attentional instability leads to impaired social information processing, impairing in idual and team performance and increasing likelihood of error, incident, and injury. Together, changes to reward seeking, the foundational components of social interaction, and interpretation of social cues, can result in unpleasant or deviant behavior. These behaviors are perceived and negatively responded to by others, leading to a cycle of conflict and withdrawal. Further studies are necessary and timely. Educational and behavioral interventions are required to reduce health-damaging behaviors, and to reduce emotionally-laden negative interpretation of sleep-deprived exchanges. This may assist with health, and with team cohesion (and improved performance and safety) in the workplace and the home.
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.EXGER.2022.111971
Abstract: People's perceptions of the mental effort required for everyday activities may drive variation in the relationships between lifestyles and cognitive ability. We asked n = 259 healthy older adults aged 60 to 70 years (90 males, 169 females) to provide a rating of the Perceived Mental Effort (PME) for each activity instance they recalled over a 48-h period as part of a time-use recall. PME was rated on a 9-point scale from "very, very low" (score of 1) to "very, very high" (score of 9). Across the entire s le, participants rated a total of 196 different activities and 17,433 activity instances. The mean PME for in idual activities was 3.50 ± 1.58. PMEs varied significantly by activity domain, with highest ratings being for Work (5.48 ± 1.72) and the lowest for Self-Care (2.89 ± 0.98). In multivariate analyses, PME ratings were higher in males than females (+0.30), PMEs were higher later in the day, increased with task duration, and decreased with age (all p < 0.0001). Time-weighted average in idual PMEs across the two days of recall ranged from 1.86 to 6.50, and were 0.3 units higher for males, but unrelated to age. Repeated intra-in idual PME ratings for the same activity were very reliable (ICC = 0.995, mean absolute difference = 0.03 ± 0.17). PMEs show promise as a reliable measure of mental effort.
Publisher: SAGE Publications
Date: 18-04-2013
Abstract: Supraspinal activity-dependent neuroplasticity may be important in the transition from acute to chronic pain. We examined neuroplasticity in a cortical region not considered to be a primary component of the central pain matrix in chronic tension-type headache (CTTH) patients. We hypothesised that neuroplasticity would be exaggerated in CTTH patients compared to healthy controls, which might explain (in part) the development of chronic pain in these in iduals. Neuroplasticity was examined following a ballistic motor training task in CTTH patients and control subjects (CS). Changes in peak acceleration (motor learning) and motor-evoked potential (MEP) litude evoked by single-pulse transcranial magnetic stimulation were compared. CTTH patients showed significantly less motor learning on the training task than CS (mean acceleration increase 87% CTTH, 204% CS, p .05), and CS but not CTTH patients showed a significant increased MEP litude following training (CS: F = 2.9, p .05 CTTH: F = 1.6, p .05). These findings suggest a deficit in use-dependent neuroplasticity within networks responsible for task performance in CTTH patients which might reflect reciprocal influences between primary motor cortex and interconnected pain processing networks. These findings may help explain the positive effects of facilitatory non-invasive brain stimulation targeting motor areas on chronic pain and help elucidate the mechanisms mediating chronic pain.
Publisher: Elsevier BV
Date: 03-2022
DOI: 10.1016/J.EXGER.2022.111698
Abstract: The relationships between cognitive function and each of physical activity, sleep and sedentary behaviour in older adults are well documented. However, these three "time use" behaviours are co-dependent parts of the 24-hour day (spending time in one leaves less time for the others), and their best balance for cognitive function in older adults is still largely unknown. This systematic review summarises the existing evidence on the associations between combinations of two or more time-use behaviours and cognitive function in older adults. Embase, Pubmed, PsycInfo, Medline and Emcare databases were searched in March 2020 and updated in May 2021, returning a total of 25,289 papers for screening. A total of 23 studies were included in the synthesis, spanning >23,000 participants (mean age 71 years). Findings support previous evidence that spending more time in physical activity and limiting sedentary behaviour is broadly associated with better cognitive outcomes in older adults. Higher proportions of moderate-vigorous physical activity in the day were most frequently associated with better cognitive function. Some evidence suggests that certain types of sedentary behaviour may be positively associated with cognitive function, such as reading or computer use. Sleep duration appears to share an inverted U-shaped relationship with cognition, as too much or too little sleep is negatively associated with cognitive function. This review highlights considerable heterogeneity in methodological and statistical approaches, and encourages a more standardised, transparent approach to capturing important daily behaviours in older adults. Investigating all three time-use behaviours together against cognitive function using suitable statistical methodology is strongly recommended to further our understanding of optimal 24-hour time use for brain function in aging.
Publisher: JMIR Publications Inc.
Date: 08-2017
DOI: 10.2196/RESPROT.7242
Publisher: Springer Science and Business Media LLC
Date: 06-12-2020
Publisher: Elsevier BV
Date: 2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2022
Publisher: Wiley
Date: 02-03-2018
DOI: 10.1113/JP275756
Publisher: Frontiers Media SA
Date: 23-05-2017
Publisher: Frontiers Media SA
Date: 03-07-2020
Publisher: Springer Science and Business Media LLC
Date: 12-11-2022
DOI: 10.1186/S12877-022-03567-6
Abstract: Although the health benefits of physical activity are well documented, most older adults are not sufficiently active. There is a need to explore approaches to physical activity promotion amongst older adults that meet the personal preferences and needs of participants, and that can be implemented on a large scale in community-based settings. The current study evaluates Daily Moves, a community-based physical activity program for older adults living in Adelaide, Australia. The Daily Moves program, which ran almost entirely during the COVID-19 pandemic, provided participants with personalized plans and information about suitable physical activity promoting activities available in their local area. This study used an explanatory sequential mixed-methods approach to evaluate associations between participation in the Daily Moves program and physical activity engagement, physical function and psychosocial wellbeing, and to explore the experiences of Daily Moves participants through qualitative interviews, with a particular focus on the impact of the COVID-19 pandemic on program participation and enjoyment. The research evaluation included 69 older adults (mean age at baseline = 73.9 ± 5.6 years 19 male). Following Daily Moves , participants reported an increase in self-report physical activity levels (mean increase = 1.8 days, p 0.001), improvements on several measures of physical function (left grip strength (mean increase = 1.8 kg, p 0.001) right grip strength (mean increase = 1.3 kg, p = 0.03) Timed Up and Go (mean decrease = 1.3 s, p 0.001)), and no significant changes in measures of psychosocial wellbeing. Qualitative interviews revealed that participants valued the supportive and flexible nature of Daily Moves, and that they felt connected with staff and other participants despite the onset of the pandemic. This evaluation demonstrates that physical activity programs embedded within the community can provide flexible and tailored recommendations to participants, and that this approach can promote positive change in important indicators of health in older adults.
Publisher: Elsevier BV
Date: 2023
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-11-2020
Abstract: Coronary artery bypass grafting (CABG) is known to improve heart function and quality of life, while rates of surgery‐related mortality are low. However, delirium and cognitive decline are common complications. We sought to identify preoperative, intraoperative, and postoperative risk or protective factors associated with delirium and cognitive decline (across time) in patients undergoing CABG. We conducted a systematic search of Medline, PsycINFO, EMBASE, and Cochrane (March 26, 2019) for peer‐reviewed, English publications reporting post‐CABG delirium or cognitive decline data, for at least one risk factor. Random‐effects meta‐analyses estimated pooled odds ratio for categorical data and mean difference or standardized mean difference for continuous data. Ninety‐seven studies, comprising data from 60 479 patients who underwent CABG, were included. Moderate to large and statistically significant risk factors for delirium were as follows: (1) preoperative cognitive impairment, depression, stroke history, and higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) score, (2) intraoperative increase in intubation time, and (3) postoperative presence of arrythmia and increased days in the intensive care unit higher preoperative cognitive performance was protective for delirium. Moderate to large and statistically significant risk factors for acute cognitive decline were as follows: (1) preoperative depression and older age, (2) intraoperative increase in intubation time, and (3) postoperative presence of delirium and increased days in the intensive care unit. Presence of depression preoperatively was a moderate risk factor for midterm (1–6 months) post‐CABG cognitive decline. This meta‐analysis identified several key risk factors for delirium and cognitive decline following CABG, most of which are nonmodifiable. Future research should target preoperative risk factors, such as depression or cognitive impairment, which are potentially modifiable. URL: www.crd.york.ac.uk rospero/ Unique identifier: CRD42020149276.
Publisher: Informa UK Limited
Date: 03-06-2011
DOI: 10.1080/13803395.2011.575769
Abstract: The assessment of cognitive function is often neglected following stroke, with no consensus on the optimal method to assess poststroke cognition. We evaluated the ability of a brief protocol to detect cognitive impairment in community-dwelling people with chronic stroke compared to healthy controls and its ability to detect changes in cognition in stroke participants undergoing an exercise intervention. Four tests of cognition were able to detect differences between the groups in the domains of executive function, memory, and information-processing speed. Stroke survivors undergoing exercise over a 5-month period showed significantly improved memory and speed of information processing. Results suggest that exercise may have the potential to improve cognition in long-term stroke survivors and that these tests are sensitive measures of poststroke cognition.
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.NEUROSCIENCE.2017.12.034
Abstract: Acute exercise studies using transcranial magnetic stimulation (TMS) can provide important insights into the mechanisms underpinning the positive relationship between regular engagement in physical activity and cortical neuroplasticity. Emerging evidence indicates that a single session of aerobic exercise can promote the response to an experimentally induced suppressive neuroplasticity paradigm however, little is known about the neuroplasticity response to facilitatory paradigms, including intermittent theta burst stimulation (iTBS). To more fully characterize the effects of exercise on brain plasticity we investigated if a single 30 min bout of high-intensity cycling (80% predicted heart rate reserve) modulated the response to an iTBS paradigm compared to rest. In 18 participants (9 females 25.5 ± 5.0 years, range: 18-35 years) iTBS was applied using standard repetitive transcranial magnetic stimulation techniques immediately following exercise or 30 min of rest. Motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous muscle at baseline, after the exercise/rest period but before iTBS, and at 5 time points following iTBS (0, 5, 10, 20 and 30 min). Contrary to our hypothesis, MEPs were suppressed following iTBS after a single 30 min bout of lower limb aerobic exercise compared to rest. These results indicate that acute aerobic exercise may not always enhance the response to an experimentally induced neuroplasticity paradigm. Further investigation of the factors that influence the relationship between exercise and neuroplasticity is warranted.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Springer Science and Business Media LLC
Date: 19-07-2009
DOI: 10.1007/S00221-009-1945-8
Abstract: This study examined whether short-latency intracortical inhibition (SICI) and/or facilitation (ICF) changes with ageing, and if this can be attributed to age-related changes in the inhibition and/or corticospinal stimulus-response curves. SICI/ICF was studied in 17 "old" (63.1 +/- 4.2 years) and 13 "young" males (20.0 +/- 2.0 years) in both hemispheres using a paired-pulse transcranial magnetic stimulation paradigm at four interstimulus intervals (1, 3, 10 and 12 ms). Motor-evoked potentials were recorded from the first dorsal interosseous muscle at rest, with a conditioning intensity set at 5% stimulator output below the active threshold (aMT). Regardless of age, SICI was greater in the left compared with the right hemisphere. SICI was increased in old men at 3 ms in the left hemisphere and at 1 ms in the in both hemispheres, but ICF was not altered. However, aMT, and hence the conditioning stimulus intensity, was higher in old men. Comparisons of pairs of young and old men with the same aMT, and of SICI curves constructed relative to aMT, failed to show any age-related increase in SICI, although age-related changes in aMT accounted for less than 20% of the variability. Corticospinal stimulus-response characteristics did not influence SICI/ICF and appear not to be altered by ageing in men. When measured in resting muscles, SICI/ICF appears unaltered by age. But it remains unknown if, when assessed during movement preparation or movement, there are changes in SICI related to functional motor changes commonly associated with ageing, such as slowing of movement.
Publisher: Wiley
Date: 21-05-2023
DOI: 10.1111/JRH.12768
Abstract: The aim of this research was to develop a contextually and culturally appropriate scale to assess farmers’ barriers to health‐related help‐seeking. An initial pool of items was developed from the academic literature and input from an expert panel of farmers, rural academics, and rural clinicians. A draft 32‐item questionnaire was then developed and sent to farmers registered with FARMbase, which is an Australian national farmer database. Two hundred and seventy‐four farmers completed the draft questionnaire (93.7% male, 73.7% aged 56‐75 years). An exploratory factor analysis identified 6 factors “Health Issues are a Low Priority,” “Concerns about Stigma,” “Structural Health System Barriers,” “Minimization and Normalization,” “Communication Barriers,” and “Continuity of Care.”. Test‐retest reliability was examined with a further 10 farmers (90% male, Mean age = 57, SD = 5.91), who completed the questionnaire twice (at 2‐ to 3‐week intervals). Results indicated moderate‐good test‐retest reliability. The resulting 24‐item Farmer Help‐Seeking Scale provides a measure of help‐seeking that is specifically designed to capture the unique context, culture, and attitudes that can interfere with farmers’ help‐seeking, and inform the development of strategies to increase health‐service utilization in this at‐risk group.
Publisher: Society for Neuroscience
Date: 14-11-2012
DOI: 10.1523/JNEUROSCI.3079-12.2012
Abstract: Preterm-born children commonly experience motor, cognitive, and learning difficulties that may be accompanied by altered brain microstructure, connectivity, and neurochemistry. However, the mechanisms linking the altered neurophysiology with the behavioral outcomes are unknown. Here we provide the first physiological evidence that human adolescents born preterm at or before 37 weeks of completed gestation have a significantly reduced capacity for cortical neuroplasticity, the key overall mechanism underlying learning and memory. We examined motor cortex neuroplasticity in three groups of adolescents who were born after gestations of ≤32 completed weeks (early preterm), 33–37 weeks (late preterm), and 38–41 weeks (term) using a noninvasive transcranial magnetic brain stimulation technique to induce long-term depression (LTD)-like neuroplasticity. Compared with term-born adolescents, both early and late preterm adolescents had reduced LTD-like neuroplasticity in response to brain stimulation that was also associated with low salivary cortisol levels. We also compared neuroplasticity in term-born adolescents with that in term-born young adults, finding that the motor cortex retains a relatively enhanced neuroplastic capacity in adolescence. These findings provide a possible mechanistic link between the altered brain physiology of preterm birth and the subsequent associated behavioral deficits, particularly in learning and memory. They also suggest that altered hypothalamic–pituitary–adrenal axis function due to preterm birth may be a significant modulator of this altered neuroplasticity. This latter finding may offer options in the development of possible therapeutic interventions.
Publisher: Springer Science and Business Media LLC
Date: 26-02-2014
DOI: 10.1007/S00221-014-3879-Z
Abstract: Regular physical activity can have positive effects on brain function and plasticity. Indeed, there is some limited evidence that even a single bout of exercise may promote plasticity within the cortex. However, the mechanisms by which exercise acutely promotes plasticity are not clear. To further explore the effects of acute exercise on cortical function, we examined whether a single bout of exercise was associated with changes in cortical excitability and inhibition. Using standard techniques, cortical stimulus-response curves [90% resting motor threshold (RMT)-150% RMT] were investigated in nine subjects (four females, 31.1 ± 11.7 years) and short-interval intracortical inhibition (SICI) [interstimulus interval 2 ms and 3 ms, conditioning intensities of 80% active motor threshold (AMT) and 90% AMT] in 13 subjects (six females, 28.4 ± 5.1 years) before and at 0 and 15 min following 30 min of ergometer cycling at low-moderate or moderate-high intensity. There were no changes in cortical excitability following exercise but less SICI at both 0 and 15 min post-exercise (F [2, 24] = 7.7, P = 0.003). These findings show that a short period of exercise can transiently reduce SICI. Such a change in inhibition after exercise may contribute to the development of a cortical environment that would be more optimal for plasticity and may partially explain previous findings of enhanced neuroplasticity following low-intensity exercise.
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.APMR.2011.01.021
Abstract: To evaluate whether aerobic exercise improves cognition in adults diagnosed with neurologic disorders. The Cochrane Central Register of Controlled Clinical Trials, MEDLINE, CINAHL, PubMed, EMBASE, PEDro, AMED, SPORTDiscus, PsycINFO, ERIC, and Google Scholar, with the last search performed in December 2010. We included controlled clinical trials and randomized controlled trials with adults diagnosed with a neurologic disorder. Studies were included if they compared a control group with a group involved in an aerobic exercise program to improve cardiorespiratory fitness and if they measured cognition as an outcome. Two reviewers independently extracted data and methodologic quality of the included trials. From the 67 trials reviewed, a total of 7 trials, involving 249 participants, were included. Two trials compared the effectiveness of yoga and aerobic exercise in adults with multiple sclerosis. Two trials evaluated the effect of exercise on patients with dementia, and 2 trials evaluated the effectiveness of exercise to improve cognition after traumatic brain injury. One trial studied the effect of a cycling program in people with chronic stroke. Lack of commonality between measures of cognition limited meta-analyses. Results from in idual studies show that aerobic exercise improved cognition in people with dementia, improved attention and cognitive flexibility in patients with traumatic brain injury, improved choice reaction time in people with multiple sclerosis, and enhanced motor learning in people with chronic stroke. There is limited evidence to support the use of aerobic exercise to improve cognition in adults with neurologic disorders. Of the 67 studies retrieved, less than half included cognition as an outcome, and few studies continued the aerobic exercise program long enough to be considered effective. Further studies investigating the effect of aerobic exercise interventions on cognition in people with neurologic conditions are required.
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.JSAMS.2019.10.015
Abstract: To synthesise the existing literature investigating if acute aerobic exercise enhances the response to experimentally-induced neuroplasticity paradigms. A systematic search of electronic databases Medline, PsycInfo and Embase was undertaken on 26 April 2018 and updated on 17 May 2019. Studies were included if they involved a bout of aerobic exercise prescribed a bout of rest as a control condition utilized a non-invasive brain stimulation paradigm to induce neuroplasticity used TMS to assess neuroplasticity outcomes participants were healthy 18-65year old males and females with no diagnosed neurological sychological impairments. Eight papers (containing 12 experiments) met inclusion criteria. All studies utilized cycling or treadmill exercise as their exercise modality, and exercise intensity ranged from low intensity continuous exercise to high-intensity interval exercise. Four neuroplasticity paradigms were employed including paired associative stimulation (PAS) (n=3), continuous theta-burst stimulation (cTBS) (n=2), intermittent theta-burst stimulation (iTBS) (n=2) and transcranial direct current stimulation (n=1). Aerobic exercise enhanced neuroplastic responses (compared to rest) in seven of the 12 experiments. This review provides emerging evidence that acute aerobic exercise can enhance the response to experimentally-induced neuroplasticity paradigms. However, there remains great variability in the study design and reporting of effects in these studies and thus a more standardized approach is encouraged to better understand the relationship between acute aerobic exercise and neuroplasticity. Future studies should consider optimizing intensity, paradigms and duration of both exercise and neuroplasticity paradigms employed.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2014
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.JSAMS.2014.03.006
Abstract: This systematic review aimed to (i) report the accuracy of submaximal exercise-based predictive equations that incorporate oxygen uptake (measured via open circuit spirometry) to predict maximal oxygen uptake (VO₂max) and (ii) provide a critical reflection of the data to inform health professionals and researchers when selecting a prediction equation. Systematic review. A systematic search of MEDLINE, EMBASE (via OvidSP), CINAHL, SPORTDiscus (via EBSCO Host) and Scopus databases was undertaken in February 2013. Studies were required to report data on healthy participants aged 18-65y. Following tabulation of extracted data, a narrative synthesis was conducted. From a total of 7597 articles screened, 19 studies were included, from which a total of 43 prediction equations were extracted. No significant difference was reported between the measured and predicted VO₂max in 28 equations. Pearson's correlation coefficient between the predicted and measured VO₂max ranged from r=0.92 to r=0.57. The variables most commonly used in predictive equations were heart rate (n=19) and rating of perceived exertion (n=24). Overall, submaximal exercise-based equations using open circuit spirometry to predict VO₂max are moderately to highly accurate. The heart rate and rating of perceived exertion methods of predicting VO₂max were of similar accuracy. Important factors to consider when selecting a predictive equation include: the level of exertion required participant medical conditions or medications the validation population mode of ergometry time and resources available for familiarisation trials and the level of bias of the study from which equations are derived.
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.YFRNE.2021.100970
Abstract: Resting-state functional magnetic resonance imaging (rs-fMRI) has been actively used in the last decade to investigate brain functional connectivity alterations in Type 2 Diabetes Mellitus (T2DM) to understand the neuropathophysiology of T2DM in cognitive degeneration. Given the emergence of new analysis techniques, this scoping review aims to map the rs-fMRI analysis techniques that have been applied in the literature and reports the latest rs-fMRI findings that have not been covered in previous reviews. Graph theory, the contemporary rs-fMRI analysis, has been used to demonstrate altered brain topological organisations in people with T2DM, which included altered degree centrality, functional connectivity strength, the small-world architecture and network-based statistics. These alterations were correlated with T2DM patients' cognitive performances. Graph theory also contributes to identify unbiased seeds for seed-based analysis. The expanding rs-fMRI analytical approaches continue to provide new evidence that helps to understand the mechanisms of T2DM-related cognitive degeneration.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Human Kinetics
Date: 08-2014
Abstract: Many equations to predict maximal oxygen uptake (V̇O 2 max) from submaximal exercise tests have been proposed for young people, but the composition and accuracy of these equations vary greatly. The purpose of this systematic review was to analyze all submaximal exercise-based equations to predict V̇O 2 max measured via direct gas analysis for use with young people. Five databases were systematically searched in February 2013. Studies were included if they used a submaximal, exercise-based method to predict V̇O 2 max the actual V̇O 2 max was gas analyzed participants were younger than 18 years and equations included at least one submaximal exercise-based variable. A meta-analysis and narrative synthesis were conducted. Sixteen studies were included. The mean equation validity statistic was strong, r = .786 (95% CI 0.747–0.819). Subgroup meta-analysis suggests exercise mode may contribute to the overall model, with running- and walking-based predictive equations reporting the highest mean r values (running r = .880 walking r = .821) and cycling the weakest ( r = .743). Selection of the most appropriate equation should be guided by factors such as purpose, logistic limitations, appropriateness of the validation s le, the level of study bias, and the degree of accuracy. Suggestions regarding the most accurate equation for each exercise mode are provided.
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.NEUROBIOLAGING.2022.09.003
Abstract: Alpha-band oscillatory activity in human electroencephalography (EEG) becomes slower and lower in litude with advanced age. However, the influence of aperiodic activity on these measures has received little consideration. We investigated whether age-related differences in aperiodic activity explains differences in resting EEG peak alpha frequency and power. We assessed aperiodic activity in 85 younger and 92 older adults by fitting the 1/f-like background activity evident in EEG power spectra using the spectral parameterization ("specparam") algorithm. Across the scalp, the aperiodic exponent and offset were smaller in older compared to younger participants, reflecting a flatter 1/f-like slope and a downward broadband shift in power spectra with age. After correcting for aperiodic activity, peak alpha frequency remained slower in older adults however, peak alpha power no longer differed statistically between age groups. The large s le size utilized in this study, as well as the depth of analysis, provides further evidence that the aperiodic component of the resting EEG signal is altered with aging and should be considered when investigating neural oscillatory activity.
Publisher: MDPI AG
Date: 04-09-2022
Abstract: This study aimed to explore barriers and facilitators that impact on farmers’ help-seeking behaviours for health and mental health concerns. Fifteen semi-structured interviews were conducted with farmers (12 male age 51.7 ± 12.6 years) from three rural regions in South Australia. Interviews explored demographic and farm-related characteristics, perceptions of in idual (and where relevant family) health and mental health concerns and experiences, and perceived barriers of health support-seeking. Thematic analysis was used to identify key themes. Four key themes were identified relating to help-seeking personal attitudes and beliefs, farm-related barriers, health system barriers and the provision of support from family and friends. Dominant personal attitudes included valuing independence, strength and privacy. Farm related barriers included the ‘farm comes first’ and the fact that ‘farm work is never done’. Health system barriers included issues relating to availability of choice and access, professionals (lack of) understanding of farm life, and time and financial costs of accessing care. Provision of support from family and friends involved informal help and advice, including facilitating access to professional support. Multiple attitudinal, structural, and farm-related issues affect farmers’ help-seeking. Professionals who understand farm work practices and routines are valued by farmers and this is likely to facilitate access to care. Workforce development programs and community programs that involve farmers’ perspectives as consumers and co-designers, using evidence-based strategies, may assist in strengthening these relationships.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.APMR.2015.09.023
Abstract: To evaluate and discuss the accuracy of submaximal exercise-based equations to predict maximum oxygen uptake (V˙o2max), validated using direct gas analysis, in older apparently healthy adults. Studies were identified by searching 5 electronic databases and manually scanning reference lists of included articles from the respective inception of each database through April 2015. Studies were included if they used at least 1 submaximal exercise-based variable in the prediction, the actual V˙o2max was directly measured using a gas analysis device, and if participants were apparently healthy older adults (mean age ≥65y). Eligible studies were required to report at least 1 validity statistic (eg, Pearson product-moment correlation [r]) and either a predicted and measured V˙o2max value or a directional significant difference between the measured and predicted V˙o2max values. No limits were placed on year of publication, but only full-text, published articles in the English language were included. Nine articles and 13 equations were retained from the systematic search strategy. If the same prediction equation was used across multiple trials, data from the most accurate trial were reported. Submaximal equations predicted directly measured V˙o2max with a moderate to strong correlation strength (r range, 0.4-0.9). Predicted V˙o2max significantly differed from directly measured in 2 of the 13 equations. The preferred mode of ergometry was walking or running (7 equations) a stepping protocol was the most accurate (R(2)=0.9, not significant between predicted and measured V˙o2max). Factors to consider when choosing a submaximal exercise-based equation are the accuracy of the equation, the population tested, the mode of ergometry, the equipment availability, and the time needed to conduct familiarization sessions.
Publisher: Elsevier BV
Date: 08-2023
Publisher: Frontiers Media SA
Date: 03-11-2023
DOI: 10.3389/FRVIR.2020.564664
Abstract: Many adults are physically inactive. While the reasons are complex, inactivity is, in part, influenced by the presence of negative feelings and low enjoyment during exercise. While virtual reality (VR) has been proposed as a way to improve engagement with exercise (e.g., choosing to undertake exercise), how VR is currently used to influence experiences during exercise is largely unknown. Here we aimed to summarize the existing literature evaluating the use of VR to influence motivation, affect, enjoyment, and engagement during exercise. A Population (clinical, and healthy), Concept (the extent and nature of research about VR in exercise, including underpinning theories), and Context (any setting, demographic, social context) framework was used. A systematic search of Medline, Scopus, Embase, PsycINFO, and Google Scholar was completed by two independent reviewers. Of 970 studies identified, 25 unique studies were included ( n = 994 participants), with most (68%) evaluating VR influences on motivation, affect, enjoyment, and engagement during exercise in healthy populations ( n = 8 studies evaluating clinical populations). Two VR strategies were prominent – the use of immersion and the use of virtual avatars and agents/trainers. All studies but one used virtual agents/trainers, suggesting that we know little about the influence of virtual avatars on experiences during exercise. Generally, highly immersive VR had more beneficial effects than low immersive VR or exercise without VR. The interaction between VR strategy and the specific exercise outcome appeared important (e.g., virtual avatars/agents were more influential in positively changing motivation and engagement during exercise, whereas immersion more positively influenced enjoyment during exercise). Presently, the knowledge base is insufficient to provide definitive recommendations for use of specific VR strategies to target specific exercise outcomes, particularly given the numerous null findings. Regardless, these preliminary findings support the idea that VR may influence experiences during exercise via multiple mechanistic pathways. Understanding these underlying mechanisms may be important to heighten effects targeted to specific exercise outcomes during exercise. Future research requires purposeful integration of exercise-relevant theories into VR investigation, and careful consideration of VR definitions (including delineation between virtual avatars and virtual agents), software possibilities, and nuanced extension to clinical populations.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.HLC.2016.09.002
Abstract: Older in iduals can now undergo invasive cardiovascular procedures without serious concern about mortality, and the numbers and proportions of the over 65s and 85s doing so in Australia has been increasing over the last 20 years. There is overwhelming evidence linking cardiovascular conditions to late-life (65 years and over) cognitive impairment and dementia including Alzheimer's Disease, primarily due to impaired cerebrovascularisation and cascading neuropathological processes. Somewhat paradoxically, these cardiovascular interventions, carried out with the primary aim of revascularisation, are not usually associated with short- or long-term improvements in cognitive function in older adults. We discuss factors associated with cognitive outcomes post-cardiovascular surgeries in patients over 65 years of age. There are many opportunities for future research: we know almost nothing about cognitive outcomes following invasive cardiac procedures in the oldest old (85 years and over) nor how to predict the cognitive/delirium outcome using pre-surgical data, and lastly, intervention opportunities exist both pre and postoperatively that have not been tested. As our population ages with increased cardiovascular burden and rates of cardiovascular interventions and surgeries, it is critical that we understand the cognitive consequences of these procedures, who is at greatest risk, and ways to optimise cognition.
Publisher: American Physiological Society
Date: 2021
DOI: 10.1152/JAPPLPHYSIOL.00288.2021
Abstract: Transcranial magnetic stimulation was used to examine GABA B -mediated inhibition during fatiguing exercise of large muscle group in older adults and young adults. We provide novel evidence to show that when older and young adults are faced with a similar magnitude of elbow flexor muscle fatigue, they have a similar decline in GABA B -mediated inhibition. This suggests that when measured in a large muscle group, older adults maintain the ability to modulate GABA B inhibition during fatiguing exercise.
Publisher: Frontiers Media SA
Date: 24-11-2022
DOI: 10.3389/FNHUM.2022.1051793
Abstract: Physical activity, sedentary behaviour and sleep are associated with cognitive function in older adults. However, these behaviours are not independent, but instead make up exclusive and exhaustive components of the 24-h day. Few studies have investigated associations between 24-h time-use composition and cognitive function in older adults. Of these, none have considered how the quality of sleep, or the context of physical activity and sedentary behaviour may impact these relationships. This study aims to understand how 24-h time-use composition is associated with cognitive function across a range of domains in healthy older adults, and whether the level of recreational physical activity, amount of television (TV) watching, or the quality of sleep impact these potential associations. 384 healthy older adults (age 65.5 ± 3.0 years, 68% female, 63% non-smokers, mean education = 16.5 ± 3.2 years) participated in this study across two Australian sites (Adelaide, n = 207 Newcastle, n = 177). Twenty-four-hour time-use composition was captured using triaxial accelerometry, measured continuously across 7 days. Total time spent watching TV per day was used to capture the context of sedentary behaviours, whilst total time spent in recreational physical activity was used to capture the context of physical activity (i.e., recreational accumulation of physical activity vs. other contexts). Sleep quality was measured using a single item extracted from the Pittsburgh Sleep Quality Index. Cognitive function was measured using a global cognition index (Addenbrooke’s Cognitive Examination III) and four cognitive domain composite scores (derived from five tests of the Cambridge Neuropsychological Test Automated Battery: Paired Associates Learning One Touch Stockings of Cambridge Multitasking Reaction Time Verbal Recognition Memory). Pairwise correlations were used to describe independent relationships between time use variables and cognitive outcomes. Then, compositional data analysis regression methods were used to quantify associations between cognition and 24-h time-use composition. After adjusting for covariates and false discovery rate there were no significant associations between time-use composition and global cognition, long-term memory, short-term memory, executive function, or processing speed outcomes, and no significant interactions between TV watching time, recreational physical activity engagement or sleep quality and time-use composition for any cognitive outcomes. The findings highlight the importance of considering all activities across the 24-h day against cognitive function in older adults. Future studies should consider investigating these relationships longitudinally to uncover temporal effects.
Publisher: American Physiological Society
Date: 2011
DOI: 10.1152/JAPPLPHYSIOL.00403.2010
Abstract: Evidence suggests that there are aging-related changes in corticospinal stimulus-response curve characteristics in later life. However, there is also limited evidence that these changes may only be evident in postmenopausal women and not in men. This study compared corticospinal stimulus-response curves from a group of young men [19.8 ± 1.6 yr (range 17–23 yr)] and a group of old men [ n = 18, aged 64.1 ± 5.0 yr (range 55–73 yr)]. Transcranial magnetic stimulation (TMS) over the contralateral motor cortex was used to evoke motor potentials at a range of stimulus intensities in the first dorsal interosseous muscle of each hand separately. There was no effect of age group or hemisphere (i.e., left vs. right motor cortex) on motor evoked potential (MEP) litude or any other stimulus-response characteristic. MEP variability was strongly modulated by resting motor threshold but not by age. M-wave (but not F-wave) litude was reduced in old men, but expressing MEP litude as a ratio of M-wave litude did not reveal any age-related differences in cortically evoked stimulus-response characteristics. We conclude that male corticospinal stimulus-response characteristics are not altered by advancing age and that previously reported age-related changes in motor cortical excitability assessed with TMS are likely due to changes inherent in the female participants only. Future studies are warranted to fully elucidate the relationship between, and functional significance of, changes in circulating neuroactive sex hormones and motor function in later life.
Publisher: Frontiers Media SA
Date: 17-03-2016
Publisher: Informa UK Limited
Date: 25-09-2017
DOI: 10.1080/23279095.2017.1363039
Abstract: This review aimed to systematically evaluate associations between the Metabolic Syndrome and domain specific cognitive performance from cross-sectional studies. PsycINFO and Medline were searched on 12 January 2017 with the terms "Metabolic Syndrome" and "cogni*." A total of 973 articles were identified, with 26 meeting inclusion criteria. In iduals with Metabolic Syndrome were consistently reported to have poorer performance on executive function tasks that were not adaptations of the verbal fluency task, including the Stockings of Cambridge test, Color-Word Inference Test and Frontal Assessment Battery findings from adaptations of the verbal fluency test showed less consistent results. Associations with performance in attention/working memory/information processing, memory, language, and construction/motor performance domains were mixed. All studies reporting on perception showed nonsignificant results. Non-language based executive function tasks appear to be the most sensitive tests of Metabolic Syndrome, and hold promise as a cognitive screen and for the tracking of interventions in this group.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-11-2020
DOI: 10.1249/MSS.0000000000002179
Abstract: Whether there are age-related differences in neural drive during maximal effort contractions is not clear. This review determined the effect of age on voluntary activation during maximal voluntary isometric contractions. The literature was systematically reviewed for studies reporting voluntary activation quantified with the interpolated twitch technique (ITT) or central activation ratio (CAR) during isometric contractions in young (18–35 yr) and old adults ( yr mean, ≥65 yr). Of the 2697 articles identified, 54 were eligible for inclusion in the meta-analysis. Voluntary activation was assessed with electrical stimulation and transcranial magnetic stimulation on five different muscle groups. Random-effects meta-analysis revealed lower activation in old compared with young adults ( d = −0.45 95% confidence interval, −0.62 to −0.29 P 0.001), with moderate heterogeneity (52.4%). To uncover the sources of heterogeneity, subgroup analyses were conducted for muscle group, calculation method (ITT or CAR), and stimulation type (electrical stimulation or transcranial magnetic stimulation) and number (single, paired, or train stimulations). The age-related reduction in voluntary activation occurred for all muscle groups investigated except the ankle dorsiflexors. Both ITT and CAR demonstrated an age-related reduction in voluntary activation of the elbow flexors, knee extensors, and plantar flexors. ITT performed with paired and train stimulations showed lower activation for old than young adults, with no age difference for the single electrical stimulation. Together, the meta-analysis revealed that healthy older adults have a reduced capacity to activate some upper and lower limb muscles during maximal voluntary isometric contractions however, the effect was modest and best assessed with at least paired stimulations to detect the difference.
Publisher: Cold Spring Harbor Laboratory
Date: 11-08-2020
DOI: 10.1101/2020.08.08.20170654
Abstract: Large systematic reviews have pointed to the efficacy of cognitive training and physical exercise on cognitive performance in older adults, making them the most common interventions in multidomain dementia prevention trials. However, it remains unclear to which extent combinations of these interventions yield additive effects beyond their in idual components and what combination strategies are most beneficial. Our aim therefore was to synthesize the evidence from randomized controlled trials of combined cognitive and physical training on cognitive, physical, psychosocial and functional outcomes in older adults with or without cognitive impairment, and to compare and rank the efficacy of the three main types of combined intervention delivery formats (simultaneous, sequential or exergaming) relative to either intervention alone or control conditions. We systematically searched MEDLINE, Embase and PsyclNFO from inception to 23 July 2019. Change from baseline to post-intervention were extracted for each outcome and results were analyzed using random-effects models. The overall efficacy of combined interventions was assessed using multivariate pairwise meta-analysis and the comparative efficacy across different intervention delivery formats and control conditions was investigated using network meta-analysis. A total of 47 trials encompassing 4052 participants were eligible, including cognitively healthy older adults ( k =30), mild cognitive impairment ( k =13), dementia ( k =2) and Parkinson’s disease ( k =2). Due to the small number of identified studies in dementia and Parkinson’s disease, these were excluded from the pooled analyses and instead summarized narratively. Relative to any control condition, combined interventions were associated with small and heterogeneous effects on overall cognitive ( k =41, Hedges’ g = 0.22, 95% CI 0.14 to 0.30, prediction interval - 0.34 to 0.78) and physical function ( k =32, g = 0.25, 95% CI 0.13 to 0.37, prediction interval - 0.46 to 0.96). Cognitive and physical effects were similar for cognitively healthy older adults and those with mild cognitive impairment. No robust evidence for benefit on psychosocial function ( k =9) or functional abilities ( k =2) was found. The efficacy of simultaneous and sequential training for cognition exceeded all control conditions apart from cognitive training alone, with small to moderate effect estimates and moderate certainty of the evidence. The efficacy of simultaneous and sequential training on physical outcomes was comparable but not significantly greater than physical exercise alone. Exergaming was ranked low for both outcomes and superior only to passive control. The certainty of the evidence was low for physical outcomes, and we were not able to compare interventions in Parkinson’s disease and dementia. Combined cognitive and physical training, delivered either simultaneously or sequentially, is efficacious for cognitive and physical outcomes in cognitively healthy and mildly impaired older adults, but not superior to cognitive or physical exercise alone in each domain. There is little systematic evidence to support potential additive effects of combined interventions or the use of exergaming in older adults. Given simultaneous training is as efficacious but less burdensome than sequential design, the former may be better suited for practical implementation to promote cognitive alongside physical health in late life. More research is needed to establish the effects of combined interventions on everyday function and well-being. PROSPERO registration number: CRD42020143509.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2018
Publisher: Human Kinetics
Date: 04-2015
Abstract: Peak oxygen uptake (V̇O 2 peak) is reliably predicted in young and middle-aged adults using a submaximal perceptually-regulated exercise test (PRET). It is unknown whether older adults can use a PRET to accurately predict V̇O 2 peak. In this study, the validity of a treadmill-based PRET to predict V̇O 2 peak was assessed in 24 participants (65.2 ± 3.9 years, 11 males). The PRET required a change in speed or incline corresponding to ratings of perceived exertion (RPE) 9, 11, 13, and 15. Extrapolation of submaximal V̇O 2 from the PRET to RPE endpoints 19 and 20 and age-predicted HRmax were compared with measured V̇O 2 peak. The V̇O 2 extrapolated to both RPE19 and 20 over-predicted V̇O 2 peak ( p .001). However, extrapolating V̇O 2 to age-predicted HRmax accurately predicted V̇O 2 peak ( r = .84). Results indicate older adults can use a PRET to predict V̇O 2 peak by extrapolating V̇O 2 from submaximal intensities to an age-predicted HRmax.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.JSAMS.2018.05.002
Abstract: Associations between objectively measured sedentary behaviour, physical activity (PA) and metabolic syndrome (MetS)-classified using three different definitions were investigated in an inactive s le of rural Australian adults. Quantitative, cross-sectional. 171 adults (50.7±12.4years) from two rural South Australian regions underwent seven-day accelerometer activity monitoring and MetS classification using the National Cholesterol Education Program, the International Diabetes Federation and the Harmonized definitions. Associations between sedentary and activity variables and MetS (adjusted for age, sex, diet and smoking status) were modelled using logistic regression. In secondary modelling, associations of sedentary and activity outcomes for each MetS definition were assessed, adjusting for other activity and sedentary variables. Prediction differences across the definitions of MetS were directly compared using Akaike's Information Criterion. Sedentary behaviour increased MetS risk, whereas light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) reduced MetS risk, irrespective of definition. In secondary models, LPA predicted MetS independently of MVPA and total sedentary time. Time spent in sedentary bouts (>30min) predicted MetS independently of MVPA and the number of sedentary bouts predicted MetS independently of LPA and MVPA. Prediction differences for MetS definitions failed to reach the critical threshold for difference (>10). This study highlights the importance of sedentary behaviour and LPA on the prevalence of MetS in an inactive s le of rural Australian adults. Studies assessing the efficacy of increasing LPA on MetS in this population are needed. Minimal predictive differences across the three MetS definitions suggest evidence from previous studies can be considered cumulative.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.MATURITAS.2019.04.204
Abstract: As the number of older people increases, so too does the prevalence of neurodegenerative disease. Worldwide, health organisations have identified the need for practical, affordable interventions to slow or delay the onset of neurodegenerative diseases such as dementia, for which there are multiple modifiable risk factors. The effects of various interventions on brain health has been investigated, including achieving sufficient physical activity, getting appropriate amounts and quality of sleep, and limiting sedentary behaviours. Few of these studies, though, have taken into account more than one lifestyle behaviour within a single study. Epidemiologists have recently initiated a paradigm shift to move away from studying the independent effects of each physical activity, sleep and sedentary behaviour, and towards an integrated 24-h time-use paradigm. Time is finite, and thus to increase time in one activity (for ex le physical activity), equal time must be taken away from other activities (sleep and sedentary behaviour). This 24-h time-use paradigm has begun to be used when studying obesity, adiposity and quality of life however, to the authors' knowledge, it has not yet been adopted by cognitive neuroscientists for the study of cognition or brain function. This narrative review synthesises the evidence for the neurophysiological effects of physical activity, sleep and sedentary behaviour independently, with a particular focus on brain structure, function and neurodegenerative disease risk. Then, we conclude with a call to action, addressing the need for studies to move towards an integrated 24-h time-use paradigm.
Publisher: Springer Science and Business Media LLC
Date: 16-04-2015
DOI: 10.1007/S00421-015-3167-Z
Abstract: The American College of Sports Medicine has highlighted the importance of considering the physiological and affective responses to exercise when setting exercise intensity. Here, we examined the relationship between exercise intensity and physiological and affective responses in active older adults. Eighteen participants (60-74 years 64.4 ± 3.9 8 women) completed a maximal graded exercise test (GXT) on a treadmill. Since time to exhaustion in the GXT differed between participants, heart rate (HR), oxygen consumption (VO2), affective valence (affect) and rating of perceived exertion (RPE) were expressed relative to the in idually determined ventilatory threshold (%atVT). During the GXT, VO2, HR and RPE increased linearly (all P 0.05) and became negative towards the end of the test (P < 0.01). In a subsequent session, participants completed a 20-min bout of self-selected exercise (at a preferred intensity). Initially, participants chose to exercise below VT (88.2 ± 17.4 %VO2atVT) however, the intensity was adjusted to work at, or above VT (107.7 ± 19.9 %VO2atVT) after 10 min (P < 0.001), whilst affect remained positive. Together, these findings indicate that exercise around VT, whether administered during an exercise test, or self-selected by the participant, is likely to result in positive affective responses in older adults.
Publisher: BMJ
Date: 02-2020
DOI: 10.1136/BMJOPEN-2019-034551
Abstract: Coronary artery bypass grafting (CABG) surgery is known to improve vascular function and cardiac-related mortality rates however, it is associated with high rates of postoperative cognitive decline and delirium. Previous attempts to prevent post-CABG cognitive decline using pharmacological and surgical approaches have been largely unsuccessful. Cognitive prehabilitation and rehabilitation are a viable yet untested option for CABG patients. We aim to investigate the effects of preoperative cognitive training on delirium incidence, and preoperative and postoperative cognitive training on cognitive decline at 4 months post-CABG. This study is a randomised, single-blinded, controlled trial investigating the use of computerised cognitive training (CCT) both pre-CABG and post-CABG (intervention group) compared with usual care (control group) in older adults undergoing CABG in Adelaide, South Australia. Those in the intervention group will complete 1–2 weeks of CCT preoperatively (45–60 min sessions, 3.5 sessions/week) and 12 weeks of CCT postoperatively (commencing 1 month following surgery, 45–60 min sessions, 3 sessions/week). All participants will undergo cognitive testing preoperatively, over their hospital stay including delirium, and postoperatively for up to 1 year. The primary delirium outcome variable will be delirium incidence (presence vs absence) the primary cognitive decline variable will be at 4 months (significant decline vs no significant decline/improvement from baseline). Logistic regression modelling will be used, with age and gender as covariates. Secondary outcomes include cognitive decline from baseline to discharge, and at 6 months and 1 year post-CABG. Ethics approval was obtained from the Central Adelaide Local Health Network Human Research Ethics Committee (South Australia, Australia) and the University of South Australia Human Ethics Committee, with original approval obtained on 13 December 2017. It is anticipated that approximately two to four publications and multiple conference presentations (national and international) will result from this research. This clinical trial is registered with the Australian New Zealand Clinical Trials Registry and relates to the pre-results stage. Registration number: ACTRN12618000799257.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.NEURON.2019.01.004
Abstract: Neuroethics is central to the Australian Brain Initiative's aim to sustain a thriving and responsible neurotechnology industry. Diverse and inclusive community and stakeholder engagement and a trans-disciplinary approach to neuroethics will be key to the success of the Australian Brain Initiative.
Publisher: Wiley
Date: 31-10-2011
DOI: 10.1111/J.1460-9568.2011.07869.X
Abstract: Afferent input has been shown to be a powerful modulator of cortical inhibition. Such modulation is likely to be important for the control of ongoing movement, but may also play a role in facilitating neuroplastic reorganisation. Human motor control and neuroplasticity both decline with ageing, whereas the efficacy of short-interval intracortical inhibition (SICI) appears not to. We examined if ageing alters the efficacy of afferent modulation of SICI. Previously, electrical cutaneous stimulation of a finger has been shown to reduce SICI in the motor cortices of young adults. Paired-pulse transcranial magnetic stimulation was used to assess SICI in the cortical representation of the first dorsal interosseous muscle. SICI was assessed separately under two conditions: with and without prior afferent input from electrical cutaneous stimulation of the index finger. Fifteen 'young' (20.1 ± 2.1 years) and 15 'old' male humans (65.5 ± 3.9 years) were studied. SICI did not differ when young and old males were compared. However, when preceded by electrical cutaneous finger stimulation, SICI was reduced in young men but not old men. Reflex testing indicated preservation of the afferent volley to the cortex. These findings suggest that a contributing factor in the decline of motor function, and possibly neuroplasticity, with ageing is loss of SICI modulation, probably due to altered cortical sensorimotor integration of afferent input.
Publisher: European Delirium Association
Date: 21-02-2023
DOI: 10.56392/001C.67976
Abstract: Cognitive impairments, including delirium, are common after coronary artery bypass grafting (CABG). Improving cognition pre- and post-operatively using computerised cognitive training (CCT) may be an effective approach to improve cognitive outcomes in CABG patients. Investigate the effect of remotely supervised CCT on cognitive outcomes, including delirium, in older adults undergoing CABG surgery. Thirty-six participants, were analysed in a single-blinded randomised controlled trial (CCT Intervention: n = 18, Control: n = 18). CCT was completed by the intervention group pre-operatively (every other day, 45–60-minute sessions until surgery) and post-operatively, beginning 1-month post-CABG (3 x 45–60-minute sessions/week for 12-weeks), while the control group maintained usual care plus weekly phone calls. Cognitive assessments were conducted pre- and post-operatively at multiple follow-ups (discharge, 4-months and 6-months). Post-operative delirium incidence was assessed daily until discharge. Cognitive change data were calculated at each follow-up for each cognitive test (Addenbrooke’s Cognitive Examination III and CANTAB z-scored). Adherence to the CCT intervention (completion of three pre-operative or 66% of post-operative sessions) was achieved in 68% of pre-CABG and 59% of post-CABG participants. There were no statistically significant effects of CCT on any cognitive outcome, including delirium incidence. Adherence to the CCT program was comparatively higher than previous feasibility studies, possibly due to the level of supervision and support provided (blend of face-to-face and home-based training, with support phone calls). Implementing CCT interventions both pre- and post-operatively is feasible in those undergoing CABG. No statistically significant benefits from the CCT interventions were identified for delirium or cognitive function post-CABG, likely due to the s le size available (study recruitment greatly impacted by COVID-19). It also may be the case that multimodal intervention would be more effective.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2020
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CLINPH.2015.02.011
Abstract: Two commonly-used methods for setting stimulus intensities in transcranial magnetic brain stimulation studies were compared to determine which best approximated a motor evoked potential (MEP) of 50% of the maximal MEP litude (SI50) a suprathreshold intensity relative to resting motor threshold (rMT) or adjusting the intensity to evoke an MEP litude of 1mV. Corticomotor stimulus-response curves and rMT for the right first dorsal interosseous (FDI) muscle of 176 subjects (aged 10-74 years) were retrospectively analysed. Regardless of subject age or sex, SI50 occurred at 127.5 ± 11.3% rMT. Except in young children, MEPs of 1 mV were significantly smaller than those evoked at SI50. In the inactive FDI muscle, a stimulus intensity of 127-128% rMT consistently gives the best approximation of SI50 in most subjects, except perhaps young children. Setting TMS stimulus intensities relative to rMT provides a less variable inter-subject comparator, with respect to in idual differences in corticomotor input-output characteristics, than adjusting the stimulator output to give an absolute MEP magnitude.
Publisher: Cold Spring Harbor Laboratory
Date: 09-2021
DOI: 10.1101/2021.08.31.458328
Abstract: Previous research using electroencephalography (EEG) and magnetoencephalography (MEG) has shown that neural oscillatory activity within the alpha band (8-12 Hz) becomes slower and lower in litude with advanced age. However, most studies have focused on quantifying age-related differences in periodic oscillatory activity with little consideration of the influence of aperiodic activity on these measures. The aim of this study was to investigate age differences in aperiodic activity inherent in the resting EEG signal. We assessed aperiodic activity in 85 healthy younger adults (mean age: 22.2 years, SD: 3.9, age range: 18–35, 37 male) and 92 healthy older adults (mean age: 66.1 years, SD: 8.2, age range 50–86, 53 male) by fitting the 1/f-like background activity evident in EEG power spectra using the fitting oscillations & one over f (FOOOF) toolbox. Across the scalp, the aperiodic exponent and offset were smaller in older compared to younger participants, reflecting a flatter 1/f-like slope and a downward broadband shift in the power spectra with age. Before correcting for aperiodic activity, older adults showed slower peak alpha frequency and reduced peak alpha power relative to younger adults. After correcting for aperiodic activity, peak alpha frequency remained slower in older adults however, peak alpha power no longer differed statistically between age groups. The large s le size utilized in this study, as well as the depth of analysis, provides further evidence that the aperiodic component of the resting EEG signal is altered with aging and should be considered when investigating neural oscillatory activity.
Publisher: SAGE Publications
Date: 20-03-2021
Abstract: Dementia has become a major public health concern globally. With no cure available and strong evidence for modifiable risk factors, it is imperative that the public are knowledgeable about dementia and to reduce their risk. The aim of this study was to measure the knowledge of dementia and its risk factors in the Australian public, as well as the number and type of information sources used. An online survey promoted through various social media platforms was completed by 596 Australian adults aged 18–78 years (59% aged 18–44 years 78% female). Eighty-eight percent of respondents were able to recognise dementia from a vignette, more so from a moderate than from a mild symptom vignette. Only 19% of respondents had a good understanding of dementia, that is describing impairment in both cognition and function. Ninety-five percent of respondents recognised that genetics and old age contributed to a person getting dementia. However, respondents had poor knowledge of empirically supported modifiable risk factors, with most viewed as likely contributors to dementia at chance levels (50%) or below. Respondents reported using informal information sources more often than formal information sources to learn about dementia. The public appear to be able to recognise the symptoms of dementia but lack understanding of how dementia impacts both a person’s cognitive functioning and ability to perform everyday tasks. Furthermore, the public remain largely unaware of empirically supported modifiable risk factors that contribute to the development of dementia. It is imperative that the public are educated on how to access and evaluate dementia-related information sources in order to increase their knowledge and understanding of dementia.
Publisher: Frontiers Media SA
Date: 30-07-2019
Publisher: American Physiological Society
Date: 08-2017
DOI: 10.1152/JAPPLPHYSIOL.01078.2016
Abstract: Aging is associated with reduced neuromuscular function, which may be due in part to altered corticospinal excitability. Regular physical activity (PA) may ameliorate these age-related declines, but the influence of PA on corticospinal excitability is unknown. The purpose of this study was to determine the influence of age, sex, and PA on corticospinal excitability by comparing the stimulus-response curves of motor evoked potentials (MEP) in 28 young (22.4 ± 2.2 yr 14 women and 14 men) and 50 old adults (70.2 ± 6.1 yr 22 women and 28 men) who varied in activity levels. Transcranial magnetic stimulation was used to elicit MEPs in the active vastus lateralis muscle (10% maximal voluntary contraction) with 5% increments in stimulator intensity until the maximum MEP litude. Stimulus-response curves of MEP litudes were fit with a four-parameter sigmoidal curve and the maximal slope calculated (slope max ). Habitual PA was assessed with tri-axial accelerometry and participants categorized into either those meeting the recommended PA guidelines for optimal health benefits ( ,000 steps/day, high-PA n = 21) or those not meeting the guidelines ( ,000 steps/day, low-PA n = 41). The MEP litudes and slope max were greater in the low-PA compared with the high-PA group ( P 0.05). Neither age nor sex influenced the stimulus-response curve parameters ( P 0.05), suggesting that habitual PA influenced the excitability of the corticospinal tract projecting to the lower limb similarly in both young and old adults. These findings provide evidence that achieving the recommended PA guidelines for optimal health may mediate its effects on the nervous system by decreasing corticospinal excitability. NEW & NOTEWORTHY Transcranial magnetic stimulation was used to determine whether achieving the recommended 10,000 steps/day for optimal health influenced the excitability of the corticospinal tract projecting to the knee extensor muscles. Irrespective of age and sex, in iduals who achieved ,000 steps/day had lower corticospinal excitability than those who performed ,000 steps/day, possibly representing greater control of inhibitory and excitatory networks. Physical activity involving ,000 steps/day may mediate its effects on the nervous system by decreasing corticospinal excitability.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2023
Publisher: BMJ
Date: 2022
DOI: 10.1136/BMJOPEN-2020-047888
Abstract: Approximately 40% of late-life dementia may be prevented by addressing modifiable risk factors, including physical activity and diet. Yet, it is currently unknown how multiple lifestyle factors interact to influence cognition. The ACTIVate Study aims to (1) explore associations between 24-hour time-use and diet compositions with changes in cognition and brain function and (2) identify duration of time-use behaviours and the dietary compositions to optimise cognition and brain function. This 3-year prospective longitudinal cohort study will recruit 448 adults aged 60–70 years across Adelaide and Newcastle, Australia. Time-use data will be collected through wrist-worn activity monitors and the Multimedia Activity Recall for Children and Adults. Dietary intake will be assessed using the Australian Eating Survey food frequency questionnaire. The primary outcome will be cognitive function, assessed using the Addenbrooke’s Cognitive Examination-III. Secondary outcomes include structural and functional brain measures using MRI, cerebral arterial pulse measured with diffuse optical tomography, neuroplasticity using simultaneous transcranial magnetic stimulation and electroencephalography, and electrophysiological markers of cognitive control using event-related potential and time frequency analyses. Compositional data analysis, testing for interactions between time point and compositions, will assess longitudinal associations between dependent (cognition, brain function) and independent (time-use and diet compositions) variables. The ACTIVate Study will be the first to examine associations between time-use and diet compositions, cognition and brain function. Our findings will inform new avenues for multidomain interventions that may more effectively account for the co-dependence between activity and diet behaviours for dementia prevention. Ethics approval has been obtained from the University of South Australia’s Human Research Ethics committee (202639). Findings will be disseminated through peer-reviewed manuscripts, conference presentations, targeted media releases and community engagement events. Australia New Zealand Clinical Trials Registry (ACTRN12619001659190).
Publisher: Springer Science and Business Media LLC
Date: 06-06-2020
Publisher: Cold Spring Harbor Laboratory
Date: 12-05-2019
DOI: 10.1101/634873
Abstract: Cardiometabolic diseases and risk factors increase the risk of late-life cognitive impairment and dementia, and have also been associated with detrimental grey and white matter changes. However the functional brain changes associated with cardiometabolic health in late-life are unclear. We sought to characterise these functional changes by recording event-related potentials (ERPs) during a n-back working memory task (0, 1 and 2 back) in 85 adults (60% female) between 50 and 80 years of age. Due to a stratified recruitment approach, participants varied widely regarding cognitive function and cardiometabolic health. Standard and objective cut-offs for high blood glucose, waist to hip ratio (i.e. obesity), high blood cholesterol, and hypertension were employed to generate a summative score for cardiometabolic burden (none, one, or two or more above cut-off). Mixed effects modelling (covarying for age and gender) revealed no statistically significant associations between cardiometabolic burden and visual P1 and N1 component litudes. There was a significant effect for the P3b component: as cardiometabolic burden increased, P3b litude decreased. We show that cardiometabolic factors related to the development of cognitive impairment and dementia in late-life associate with functional brain activity, as recorded via ERPs. Findings have relevance for the monitoring of lifestyle interventions (typically targeting cardiometabolic factors) in ageing, as ERPs may provide a more sensitive measure of change than cognitive performance. Further, our results raise questions related to the findings of a broad range of ERP studies where the groups compared may differ in their cardiometabolic health status (not only in psychological symptomatology).
Publisher: Informa UK Limited
Date: 30-09-2019
Publisher: PeerJ
Date: 04-10-2023
DOI: 10.7717/PEERJ.16095
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JSAMS.2018.07.002
Abstract: Rural Australian adults are consistently identified as insufficiently active, likely due to challenges implementing community-based physical activity programs in rural settings. On-line strategies to promote physical activity may be particularly effective in rural settings where isolation and scarcity of qualified support are potential barriers. The Rural Environments and Community Health (REACH) study evaluated the effectiveness of an online-delivered walking intervention among South Australian rural adults. Randomised controlled study design. A twelve-week intervention, with six- and twelve-month follow-up, was conducted. Participants (n=171 50.6±12.5years), recruited through flyers, local newspapers and radio, were randomised to comparison or intervention groups and received a pedometer. The intervention group received access to the REACH website and personalised step goals based on ratings of perceived exertion and daily affect. The comparison group received a paper diary and generic step goals. Outcome measures were accelerometry-assessed sedentary, light (LPA) and moderate-to-vigorous (MVPA) physical activity. Linear mixed models assessed changes over the intervention and follow-ups. Sedentary time decreased, and LPA and MVPA increased in both groups across the intervention (p<0.05). The intervention group demonstrated a larger increase in LPA at six-month follow-up relative to comparison (p<0.05). Both groups decreased sedentary time, overall and in bouts ≥30min, between baseline and twelve-month follow-up (p<0.05). From baseline to twelve-month follow-up, MVPA (total min and bouts ≥10min) declined more in the comparison group than the intervention group (p<0.05). While increased physical activity and decreased sedentary time were observed in both groups during the intervention period, maintenance was only observed for LPA at six-month follow-up in the intervention group. By twelve-month follow-up, post-intervention improvements had largely disappeared, suggesting that additional research is needed to identify ways to improve long-term adherence.
Start Date: 2016
End Date: 2017
Funder: Judith Jane Mason and Harold Stannett Williams Memorial Foundation
View Funded ActivityStart Date: 2016
End Date: 2017
Funder: University of South Australia
View Funded ActivityStart Date: 2015
End Date: 2017
Funder: Alzheimer's Australia Dementia Research Foundation
View Funded ActivityStart Date: 2019
End Date: 2024
Funder: National Health and Medical Research Council
View Funded Activity