Age-related changes in responsiveness to non-invasive brain stimulation neuroplasticity paradigms: A systematic review with meta-analysis.

OBJECTIVES: We aimed to summarise and critically appraise the available evidence for the effect of age on responsiveness to non-invasive brain stimulation (NBS) paradigms delivered to the primary motor cortex. METHODS: Four databases (Medline, Embase, PsycINFO and Scopus) were searched from inception to February 7, 2023. Studies investigating age group comparisons and associations between age and neuroplasticity induction from NBS paradigms were included. Only studies delivering neuroplasticity paradigms to the primary motor cortex and responses measured via motor-evoked potentials (MEPs) in healthy adults were considered. RESULTS: 39 studies, encompassing 40 experiments and eight NBS paradigms were included: paired associative stimulation (PAS; n = 12), repetitive transcranial magnetic stimulation (rTMS; n = 2), intermittent theta burst stimulation (iTBS; n = 8), continuous theta burst stimulation (cTBS; n = 7), transcranial direct and alternating current stimulation ((tDCS; n = 7; tACS; n = 2)), quadripulse stimulation (QPS; n = 1) and i-wave periodic transcranial magnetic stimulation (iTMS; n = 1). Pooled findings from PAS paradigms suggested older adults have reduced post-paradigm responses, although there was considerable heterogeneity. Mixed results were observed across all other NBS paradigms and post-paradigm timepoints. CONCLUSIONS/SIGNIFICANCE: Whilst age-dependent reduction in corticospinal excitability is possible, there is extensive inter- and intra-individual variability both within and between studies, making it difficult to draw meaningful conclusions from pooled analyses.

Cross-sectional associations between 24-hour time-use composition, grey matter volume and cognitive function in healthy older adults.

BACKGROUND: 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. METHODS: 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, hippocampi, 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. RESULTS: 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 sample 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. CONCLUSIONS: Although 24-hour time use was not associated with total or regional grey matter independently, total grey matter and frontal lobe grey matter volume moderated 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.

Food, nutrition and the dining experience in aged care settings: Findings of a nationwide survey.

OBJECTIVE: Previous research on food, nutrition and dining practices in Australian residential aged care (RAC) homes has been based on a limited sample of single-home or multiple-home providers, but a nationwide study has not been conducted. The aim of this study was to provide a preliminary overview of current food, nutrition and dining practices across Australian RAC facilities using a nationwide survey. METHODS: A survey was distributed to Australian RAC homes in August-September 2020, as part of the National Congress on Food, Nutrition and the Dining Experience in Aged Care (February 2021). The survey, administered via an online portal, consisted of 38 semistructured questions including yes/no or multiple-choice responses, free text, frequency scales and number entry. Six key topics were explored, including 'food service system and environment', 'catering style', 'menu planning and evaluation', 'nutrition planning and requirements', 'nutrition-related screening and assessment' and 'training and additional information', which were informed by the Australian Government Department of Health and reflected the interests of the Congress. RESULTS: The final sample included 292 respondents (204 individual homes and 88 multiple-home proprietors) representing 1152 homes and 125,393 residents, encompassing approximately 43% of RAC homes (of a possible 2671) and 57% of residents (of a possible 219,965) in Australia. Survey respondents representing RAC homes included service managers, catering managers, Chief Executive Officers, cooks, chefs, dietitians or staff from other roles within homes. A number of potential areas of need were identified, included increasing the autonomy of residents to select the foods they desire, increasing the variety and choice (including timing) of meals, enhancing the dining environments in homes to stimulate food intake and increasing staff training and the number of trained chefs in homes, so that meals are prepared which address diverse nutritional needs of residents. CONCLUSIONS: This study provides insight into the food service and mealtime practices of over a third of Australian RAC homes. The findings of this survey may help to identify key targets for intervention to improve the food, nutrition and quality of life of aged care residents.

The association between reallocations of time and health using compositional data analysis: a systematic scoping review with an interactive data exploration interface.

BACKGROUND: How time is allocated influences health. However, any increase in time allocated to one behaviour must be offset by a decrease in others. Recently, studies have used compositional data analysis (CoDA) to estimate the associations with health when reallocating time between different behaviours. The aim of this scoping review was to provide an overview of studies that have used CoDA to model how reallocating time between different time-use components is associated with health. METHODS: A systematic search of four electronic databases (MEDLINE, Embase, Scopus, SPORTDiscus) was conducted in October 2022. Studies were eligible if they used CoDA to examine the associations of time reallocations and health. Reallocations were considered between movement behaviours (sedentary behaviour (SB), light physical activity (LPA), moderate-to-vigorous physical activity (MVPA)) or various activities of daily living (screen time, work, household chores etc.). The review considered all populations, including clinical populations, as well as all health-related outcomes. RESULTS: One hundred and three studies were included. Adiposity was the most commonly studied health outcome (n = 41). Most studies (n = 75) reported reallocations amongst daily sleep, SB, LPA and MVPA. While other studies reported reallocations amongst sub-compositions of these (work MVPA vs. leisure MVPA), activity types determined by recall (screen time, household chores, passive transport etc.) or bouted behaviours (short vs. long bouts of SB). In general, when considering cross-sectional results, reallocating time to MVPA from any behaviour(s) was favourably associated with health and reallocating time away from MVPA to any behaviour(s) was unfavourably associated with health. Some beneficial associations were seen when reallocating time from SB to both LPA and sleep; however, the strength of the association was much lower than for any reallocations involving MVPA. However, there were many null findings. Notably, most of the longitudinal studies found no associations between reallocations of time and health. Some evidence also suggested the context of behaviours was important, with reallocations of leisure time toward MVPA having a stronger favourable association for health than reallocating work time towards MVPA. CONCLUSIONS: Evidence suggests that reallocating time towards MVPA from any behaviour(s) has the strongest favourable association with health, and reallocating time away from MVPA toward any behaviour(s) has the strongest unfavourable association with health. Future studies should use longitudinal and experimental study designs, and for a wider range of outcomes.

Corrigendum: Twenty-four-hour time-use composition and cognitive function in older adults: cross-sectional findings of the ACTIVate study.

[This corrects the article DOI: 10.3389/fnhum.2022.1051793.].

Twenty-four-hour time-use composition and cognitive function in older adults: Cross-sectional findings of the ACTIVate study.

Introduction: 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. Methods: 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. Results: 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. Discussion: 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.

Mixed-methods evaluation of Daily Moves, a community-based physical activity program for older adults.

BACKGROUND: 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.  METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

The perceived mental effort of everyday activities in older adults.

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 sample, participants rated a total of 196 different activities and 17,433 activity instances. The mean PME for individual 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 individual 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-individual 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.

Does APOE ɛ4 Status Change How 24-Hour Time-Use Composition Is Associated with Cognitive Function? An Exploratory Analysis Among Middle-to-Older Adults.

BACKGROUND: The 24 h time-use composition of physical activity, sedentary behavior, and sleep is linked to cognitive function in adults and may contribute to future dementia risk. However, the impact of reallocating time between behaviors may differ depending on an individual's genetic dementia risk. OBJECTIVE: To explore if there is an interaction between 24 h time-use composition and genetic dementia risk in relation to cognitive function, and to simulate how time-reallocations are associated with cognitive function across different levels of genetic dementia risk. METHODS: Cross-sectional global cognition, executive function, genetic dementia risk (at least one apolipoprotein (APOE) ɛ4 allele versus none) and 7 days of 24 h accelerometry (average daily time-use composition of moderate-to-vigorous physical activity (MVPA), light physical activity, sedentary behavior, sleep) were collected from 82 adults (65.6±7.5 years, 49 females). Linear regression was used to explore the relationship between time-use composition and cognitive measures, testing for interaction between APOE ɛ4 status and time-use composition. The models were used to simulate time reallocations in both APOE ɛ4 status groups. RESULTS: The 24 h time-use composition was associated with global cognition (F = 2.4, p = 0.02) and executive function (F = 2.6, p = 0.01). For both measures, the association differed according to genetic risk (interactions p < 0.001). In both APOE groups, reallocating time to MVPA was beneficially associated with measures of cognitive function, but associations were larger among those with at least one APOE ɛ4 allele. CONCLUSION: Genetic dementia risk may impact the effectiveness of activity interventions. Increasing MVPA may provide greater benefits among those with higher genetic dementia risk.

Characterising activity and diet compositions for dementia prevention: protocol for the ACTIVate prospective longitudinal cohort study.

INTRODUCTION: 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. METHODS AND ANALYSIS: 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. CONCLUSIONS: 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 AND DISSEMINATION: 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. TRIAL REGISTRATION NUMBER: Australia New Zealand Clinical Trials Registry (ACTRN12619001659190).

How are combinations of physical activity, sedentary behaviour and sleep related to cognitive function in older adults? A systematic review.

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.

Combined physical and cognitive training for older adults with and without cognitive impairment: A systematic review and network meta-analysis of randomized controlled trials.

Combining physical exercise with cognitive training is a popular intervention in dementia prevention trials and guidelines. However, it remains unclear what combination strategies are most beneficial for cognitive and physical outcomes. We aimed to compare the efficacy of the three main types of combination strategies (simultaneous, sequential or exergaming) to either intervention alone or control in older adults. Randomized controlled trials of combined cognitive and physical training were included in multivariate and network meta-analyses. In cognitively healthy older adults and mild cognitive impairment, the effect of any combined intervention relative to control was small and statistically significant for overall cognitive (k = 41, Hedges' g = 0.22, 95 % CI 0.14 to 0.30) and physical function (k = 32, g = 0.25, 95 % CI 0.13 to 0.37). Simultaneous training was the most efficacious approach for cognition, followed by sequential combinations and cognitive training alone, and significantly better than physical exercise. For physical outcomes, simultaneous and sequential training showed comparable efficacy as exercise alone and significantly exceeded all other control conditions. Exergaming ranked low for both outcomes. Our findings suggest that simultaneously and sequentially combined interventions are efficacious for promoting cognitive alongside physical health in older adults, and therefore should be preferred over implementation of single-domain training.

Acute aerobic exercise and neuroplasticity of the motor cortex: A systematic review.

OBJECTIVES: To synthesise the existing literature investigating if acute aerobic exercise enhances the response to experimentally-induced neuroplasticity paradigms. METHODS: 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/psychological impairments. RESULTS: 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. CONCLUSIONS: 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.

Building your best day for healthy brain aging-The neuroprotective effects of optimal time use.

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 example 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.