Physical activity and the maintenance of cognitive function

Association between physical activity and episodic memory and the moderating effects of the apolipoprotein E ε4 allele and age

Background

An abundance of evidence indicates that physical activity may protect against Alzheimer's disease (AD) and related cognitive decline. However, little is known about the association between physical activity and AD-related cognitive decline according to age and the apolipoprotein E (APOE) ε4 allele (APOE4) as major risk factors. Therefore, we examined whether age and APOE4 status modulate the effects of physical activity on episodic memory as AD-related cognition in non-demented older adults.

Methods

We enrolled 196 adults aged between 65 and 90 years, with no dementia. All participants underwent comprehensive clinical assessments including physical activity evaluation and APOE genotyping. The AD-related cognitive domain was assessed by the episodic memory, as the earliest cognitive change in AD, and non-memory cognition for comparative purposes. Overall cognition was assessed by the total score (TS) of the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery.

Results

We found significant physical activity × age and physical activity × APOE4 interaction effects on episodic memory. Subgroup analyses indicated that an association between physical activity and increased episodic memory was apparent only in subjects aged > 70 years, and in APOE4-positive subjects.

Conclusion

Our findings suggest that physical activity has beneficial effects on episodic memory, as an AD-related cognitive domain, in individuals aged > 70 years and in APOE4-positive individuals. Physicians should take age and APOE4 status account into when recommending physical activity to prevent AD-related cognitive decline.

An umbrella review of randomized control trials on the effects of physical exercise on cognition

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval -0.09 to 0.14). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

Physical Activity and Cognition in Sedentary Older Adults: A Systematic Review and Meta-Analysis

Background:

Epidemiologic evidence suggests that physical activity benefits cognition, but results from randomized trials in sedentary individuals are limited and inconsistent.

Objective:

To evaluate the effects of physical activity on cognition among sedentary older adults.

Objective:

A systematic literature search for eligible studies published up to January 1, 2021, was performed on six international (PubMed, Cochrane Library, Web of Science, Sinomed, FMRS, and OVID) and three Chinese databases (Wanfang, China National Knowledge Infrastructure, and VIP). We estimated the effect of physical activity on the cognition of sedentary elderly by standardized mean differences (SMD) and 95% confidence intervals (CI) using a random-effects model. We evaluated publication bias using funnel plots and heterogeneity using I² statistics. Subgroup analyses were conducted by baseline cognition, intervention duration, activity type, and country.

Results:

Seven randomized controlled trials (RCTs) comprising 321 (experimental group, 164; control group, 157) sedentary older adults were included in the meta-analysis. Physical activity significantly improved cognition in sedentary elderly adults compared with controls (SMD: 0.50, 95% CI:0.09–0.92). Subgroup analyses showed significant effects of baseline cognition impairment (SMD: 9.80, 95% CI: 5.81–13.80), intervention duration > 12 weeks (SMD: 2.85, 95% CI: 0.73–4.96), aerobic exercise (SMD: 0.74, CI: 0.19–1.29), and countries other than the United States (SMD: 10.50, 95% CI: 7.08–13.92).

Conclusion:

Physical activity might have a general positive effect on the cognition of sedentary older adults. Intervention > 12 weeks and aerobic exercise can effectively delay their cognitive decline; however, more rigorous RCTs are needed to support our findings.

The association between sedentary behavior and cognitive ability in older adults

Executive functions (EF) are a grouping of cognitive abilities essential for daily life. Previous research has shown that physical activity (PA) may in fact preserve EF in older adults, but the link between sedentary behavior (SB) and cognitive ability has been less explored. The purpose of this study was to examine the relationship between SB and cognition (executive function and memory) in older adults. Seventy five older adults (74.6 ± 9 years) self-reported their sedentary time (ST) and PA, as well as EF ability (paper-based measure of EF). Participants also completed several performance-based measures of EF and a memory task. Older adults who were less sedentary had superior EF and memory (e.g., Stroop time was significantly faster in less sedentary adults (34.7 s ± 1.9) compared to more sedentary adults (39.6 s ± 1.8), p = .02). Regression analysis showed that total ST was associated with several measures of EF after adjusting for age, and physical activity (e.g., Stroop time β =  .005 (.002, .009). Less cognitively demanding SB (TV viewing and napping) was associated with worse performance on most EF and in the memory task. Performing a hobby was also associated with lower levels of EF and memory. For example, the building times for the Lego task were positively related to napping (r² = .34), watching TV (r² = .27), and performing a hobby (r² = .46). Associations of ST with cognitive abilities were more pronounced in older adults who engaged in less PA. These results suggest that SB may play an important role in cognitive abilities of older adults. Longitudinal studies using performance-based assessments of EF are needed. Lara Coelho and Kayla Hauck contributed equally to the manuscript.

Interplay between hormones and exercise on hippocampal plasticity across the lifespan

The hippocampus is a brain structure known to play a central role in cognitive function (namely learning and memory) as well as mood regulation and affective behaviors due in part to its ability to undergo structural and functional changes in response to intrinsic and extrinsic stimuli. While structural changes are achieved through modulation of hippocampal neurogenesis as well as alterations in dendritic morphology and spine remodeling, functional (i.e., synaptic) changes can be noted through the strengthening (i.e., long-term potentiation) or weakening (i.e., long-term depression) of the synapses. While age, hormone homeostasis, and levels of physical activity are some of the factors known to module these forms of hippocampal plasticity, the exact mechanisms through which these factors interact with each other at a given moment in time are not completely understood. It is well known that hormonal levels vary throughout the lifespan of an individual and it is also known that physical exercise can impact hormonal homeostasis. Thus, it is reasonable to speculate that hormone modulation might be one of the various mechanisms through which physical exercise differently impacts hippocampal plasticity throughout distinct periods of an individual's life. The present review summarizes the potential relationship between physical exercise and different types of hormones (namely sex, metabolic, and stress hormones) and how this relationship may mediate the effects of physical activity during three distinct life periods, adolescence, adulthood, and senescence. Overall, the vast majority of studies support a beneficial role of exercise in maintaining hippocampal hormonal levels and consequently, hippocampal plasticity, cognition, and mood regulation.

Drum Communication Program Intervention in Older Adults With Cognitive Impairment and Dementia at Nursing Home: Preliminary Evidence From Pilot Randomized Controlled Trial

Introduction: Inactivity and consequent deterioration of cognitive and physical function is a major concern among older adults with the limited walking ability and need a high level of care in nursing homes. We aimed to test whether a drumming communication program (DCP) that uses the rhythmic response function of the elderly with cognitive impairment, dementia, and other debilitating disorders would improve their cognitive and physical function. Methods: We conducted a Randomized Controlled Trial (RCT) to investigate the effects of the DCP in 46 nursing home residents who needed high levels of nursing care. The participants were randomly assigned to an intervention and control group. The intervention group attended 30 min of the DCP thrice a week for 3 months. Cognitive function was measured using the Mini-Mental State Examination-Japanese (MMSE-J) and Frontal Assessment Battery (FAB). Physical function was measured using grip strength and active upper limb range of motion with the dominant hand. Body composition was measured using bioelectrical impedance analysis (BIA). These measures were analyzed before and after the DCP intervention period, and data for the two groups were compared thereafter. Results: Initially, the participants had low scores on the MMSE-J, and 84.78% of them used wheelchairs. Following the DCP intervention, the MMSE-J and FAB scores of the DCP group improved significantly. In terms of motor function, the active range of motion of the wrist palmar and the shoulder flexion improved in the intervention group. Regarding body composition, the skeletal muscle mass index, total body protein, and the dominant hand muscle mass that was adding physical load decreased. Conclusions: The DCP provided the participants with an opportunity to engage in continued exercise for 3 months. The intervention group exhibited improved cognitive function and upper limb motion range, and changes in body composition. The results suggest that DCP can be used as an intervention method to promote exercise and improve various health and cognitive functions. Trial Registration: This trial was registered at the University Hospital Medical Information Network Clinical Trial Registry (UMIN000024714) on 4 November 2016. The URL is available at https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000028399.

Influencing Factors and Exercise Intervention of Cognitive Impairment in Elderly Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common respiratory condition characterized by airflow limitation in the elderly. Airflow limitation is partially reversible and progressive. COPD not only causes a gradual decline in lung function but also affects the function of other systems throughout the body; it also has adverse effects on the central nervous system that can lead to cognitive impairment, especially in elderly patients. Therefore, understanding the influencing factors of cognitive impairment in elderly patients with COPD and applying early intervention are crucial in improving the quality of life of patients and reducing the burden on their families and society. This article mainly discusses the related factors of cognitive impairment in elderly patients with COPD and expands the possible mechanism of exercise in improving cognitive impairment in patients with COPD to provide a reference for the clinical prevention and treatment of cognitive impairment in elderly patients with COPD.

An integrative review of exercise interventions among community-dwelling adults with Alzheimer's disease

AIMS

To synthesise the current research on exercise interventions and health-related outcomes among community-dwelling adults with Alzheimer's disease (AD).

METHODS

Integrative review of the literature reporting exercise interventions among people with AD living in the communities.

RESULTS

Seventeen studies presented in 24 quantitative papers with 1,068 participants diagnosed with Alzheimer's disease were reviewed. The interventions varied in intervention programme characteristics (e.g. baseline assessments, type of exercise, exercise dose, outcome measurements). Among them, (a) 13 studies appeared beneficial to physical fitness in different areas; (b) 9 studies reported the effects on cognitive ability and two studies showed the positive effects; (c) 12 studies reported the participants' adherence, but only 2 studies reported the participants' adherence using attendance and training intensity.

CONCLUSION

Exercise is proven to be effective in physical fitness among community-dwelling patients with AD. Future studies should verify the effects on cognitive function and possible mechanisms of different exercise types using more sensitive and objective outcome measurements. Additionally, treatment fidelity, cost-effectiveness and long-term effects should be explored.

IMPLICATION FOR PRACTICE

Exercise may be effective and feasible for community-dwelling people with AD, but its effects on cognition need to be verified in the future. This review provided recommendations for assisting nurses and other clinicians in developing, implementing, and/or evaluating exercise interventions for patients with AD.

The effectiveness of home-based exercise programmes on mobility and functional independence in community-dwelling adults with Alzheimer's disease: a critical review

Background/Aims

In the UK, two-thirds of people with dementia are community-dwelling. Guidelines recommend exercise to promote independence among this population, however evidence to support this is scarce. This study aimed to evaluate the effectiveness of home-based exercise programmes on mobility and functional independence in people with Alzheimer's disease living in the community.

Methods

The following electronic databases were searched: AMED, CINAHL, EMBASE, Medline, SPORTsDiscus, The Cochrane Library, PEDro, OpenGrey and Online Thesis. All included trials were assessed for methodological quality using PEDro bias scores and McMaster's Critical Appraisal Tool and Guideline. English language restrictions were applied.

Results

A total of seven trials were included within the review. Trial quality was mixed. All trials reported measures for mobility, while five trials included measures of functional independence. Results for the effectiveness of home-based exercise on mobility were mixed, with only two studies reporting significant improvements. Functional independence significantly improved in all trials.

Conclusions

The effectiveness of home-based exercise programmes on mobility in community-dwelling people with Alzheimer's disease remains inconclusive, while a growing body of evidence indicates its effectiveness in improving functional independence. However, high quality trials are scarce. Larger, randomised, controlled trials specific to this population are thus warranted.

Similar changes in executive function after moderate resistance training and loadless movement

Growing evidence suggests that physical exercise may improve cognitive function in the short- and long-term. Aerobic exercise has been studied most extensively. Preliminary work suggests that resistance training also improves cognitive function, particularly executive function. Conversely, most studies found little dose-effect by intensity. Consequently, cognitive benefits may be elicited, at least in part, by the movement rather than the physical exertion of resistance training. The objective here was to examine and compare acute changes in executive function after resistance training and a loadless movement control among young, healthy adults. Twenty-two young healthy adults (mean age 23.4 years [2.4]; 50% female) completed three conditions, a baseline condition and two experimental conditions (moderate intensity resistance training, loadless movement control). Participants completed a computerized modified Stroop task with concurrent electroencephalography (EEG) before and 10, 20, 30, and 40min after each intervention. Outcomes (incongruent and congruent response time, accuracy, EEG P3 amplitude and latency) were analyzed using mixed linear regression models (factors: condition, time, condition*time). There was a main effect of time for Stroop response time (F_4,84 = 3.94, p = 0.006 and F_4,84 = 10.27, p<0.0001 respectively) and incongruent and congruent P3 amplitude (F_4,76 = 4.40, p = 0.003 and F_4,76 = 5.09, p = 0.001 respectively). Post-hoc analyses indicated that both incongruent and congruent P3 amplitude were elevated at time points up to and including 40min after the interventions (compared to pre-intervention, p<0.05). Both incongruent and congruent response times were faster at 10min post-intervention than pre-intervention (p<0.04). There was no main effect of condition or interaction between condition and time for either outcome (p≥0.53). Similar improvements in executive function were observed after loadless movement and resistance training, suggesting that movement is at least partially responsible for the benefits to executive function. Future research should continue to probe the influence of movement versus physical exertion in resistance training by including a movement and non-movement control.

The added value of therapist communication on the effect of physical therapy treatment in older adults; a systematic review and meta-analysis

OBJECTIVE

Lower physical activity levels in older adults are associated with increased co-morbidities and disability. Physical therapists have a critical role in facilitating increases in physical activity. The communication they use may impact their effectiveness. This study investigates the additional value of therapist's communication during physical therapy on older adults' physical activity levels.

METHODS

Systematic review and meta-analysis. Clinical trials were identified in PubMed, CINAHL, Embase, PsycINFO, PEDro, Cochrane, up to July 2016. Communication was classified with the Behavior Change Taxonomy(BCT). Effect sizes were pooled using Cochrane's Review-Manager. Strength of the evidence was analyzed using GRADE's criteria.

RESULTS

Twelve studies were identified. Overall, communication techniques revealed an immediate and long-term effect(ES:0.19;0.24) on self-reported physical activity measures but not on performance-based, with moderate to high strength of evidence. Divided in BCT-categories, only 'Generalisation of target behavior', defined as communication aimed to help patients generalise an exercise from one situation to another at home, had a positive effect on self-reported activity(ES:0.34), with low strength of evidence.

CONCLUSION

Adding a communication technique to physical therapy is effective on self-reported physical activity measures but not on performance-based measures.

PRACTICE IMPLICATIONS

Add communication to exercise when treatment aims at perceived, but not performed, physical activity.

The effects of physical exercise on executive function in community-dwelling older adults living with Alzheimer's-type dementia: A systematic review

Executive function deficit is an indicator of Alzheimer's-type dementia and manifests as disruptions of attentional control, memory, cognitive flexibility, planning, and reasoning, among other cognitive problems. Physical exercise is suggested to have a protective effect on global cognition with aging. However, whether it influences executive function in people living with Alzheimer's-type dementia specifically is unknown. The current systematic review examined the efficacy of physical exercise on executive function performance in community-dwelling older adults living with Alzheimer's-type dementia. An electronic search of databases retrieved randomized and non-randomized controlled trials of community-dwelling older adults diagnosed with Alzheimer's-type dementia who completed a physical exercise intervention and who were assessed using an executive function outcome measure. Methodological quality of six studies meeting the inclusion criteria published between 2009 and 2016 was scored independently by two raters using the Physiotherapy Evidence Database and a Cochrane informed domain-based assessment of risk of bias. Trends toward improvement in executive function scores were seen across all six studies, and significant improvement was seen in four of the eligible studies. Future studies should explore the benefits of the American College of Sports Medicine recommended 150 min of physical exercise per week with select measures of executive function.

How Does Exercise Reduce the Rate of Age-Associated Cognitive Decline? A Review of Potential Mechanisms

The rate of age-associated cognitive decline varies considerably between individuals. It is important, both on a societal and individual level, to investigate factors that underlie these differences in order to identify those which might realistically slow cognitive decline. Physical activity is one such factor with substantial support in the literature. Regular exercise can positively influence cognitive ability, reduce the rate of cognitive aging, and even reduce the risk of Alzheimer's disease (AD) and other dementias. However, while there is substantial evidence in the extant literature for the effect of exercise on cognition, the processes that mediate this relationship are less clear. This review examines cardiovascular health, production of brain derived neurotrophic factor (BDNF), insulin sensitivity, stress, and inflammation as potential pathways, via which exercise may maintain or improve cognitive functioning, and may be particularly pertinent in the context of the aging brain. A greater understanding of these mechanisms and their potential relationships with exercise and cognition will be invaluable in providing biomarkers for investigating the efficacy of differing exercise regimes on cognitive outcomes.

The role of exercise in mitigating subcortical ischemic vascular cognitive impairment

Subcortical ischemic vascular cognitive impairment (SIVCI) is the most preventable form of cognitive dysfunction. There is converging evidence from animal and human studies that indicate vascular injury as the primary cause of SIVCI. Currently, there are no curative pharmaceutical treatments for vascular dementia; however, exercise may be a promising strategy to combat SIVCI. This review will focus on the role of exercise as a strategy to prevent or slow the progression of SIVCI, with particular emphasis on the mechanisms by which exercise may improve cerebrovascular function. We propose that exercise may be an effective strategy to combat SIVCI by improving cognitive function, increasing the bioavailability of neurotrophins, stimulating endothelial function, and controlling vascular risk factors. This article is part of the Special Issue "Vascular Dementia".

The Effects of a Multicomponent Dyadic Intervention With Physical Exercise on the Cognitive Functioning of People With Dementia: A Randomized Controlled Trial

The objective was to evaluate the effects of a multicomponent dyadic intervention on the cognitive functioning of people with dementia living at home in a randomized controlled trial. People with dementia and their family caregivers (n = 111) were randomly assigned to 8 home-based sessions including physical exercise and support or a minimal intervention consisting of monthly written information bulletins and monthly phone calls. Memory, executive functioning (EF), and attention were assessed at baseline, and after 3 (postmeasurement) and 6 months (follow-up). Data were analyzed by using generalized estimating equations (GEE). A small, significant effect was found on attention. No effects were found on memory and EF. Finding only a small significant effect might be explained by the ineffectiveness of the intervention, but also by moderate treatment adherence or a lack of room for improvement because half of the people with dementia were already receiving care in a day care facility.

Effectiveness of cognition-focused interventions in activities of daily living performance in people with dementia: A systematic review

Introduction

Dementia affects cognitive functions and has a direct impact on the ability to perform activities of daily living. Studies have focused on the impact of cognition-focused interventions on cognitive functions, but less on the daily functionality of people with dementia. The aim of this study was to review systematically evidence of the effectiveness of cognition-focused interventions on the ability of people with dementia to perform activities of daily living.

Method

A search of randomised controlled trials was performed in 10 databases to find all available evidence on the subject. Two reviewers independently selected articles based on predetermined inclusion criteria. The articles had to describe randomised controlled trials involving cognition-focused interventions in people with some form of dementia, aged 65 years or over, and specify their score on the Mini-Mental State Examination or the Clinical Dementia Rating. Eleven articles met the inclusion criteria for the review.

Results

Cognitive rehabilitation through functional tasks led to maintenance or improvement in everyday tasks in some cases. In cognitive stimulation studies the subjects maintained their performance in activities of daily living with respect to the control condition, but this was not the case in reminiscence stimulation groups. Subjects who underwent cognitive training of cognitive functions did not show significant improvements in activities of daily living.

Conclusion

The evidence on the effectiveness of cognition-focused interventions suggests that multi-component programmes that include cognitive rehabilitation or cognitive stimulation could maintain or improve functionality in people with dementia.

Reach the Person behind the Dementia - Physical Therapists' Reflections and Strategies when Composing Physical Training

Dementia is a disease characterized by cognitive impairment and physical decline that worsens over time. Exercise is one lifestyle factor that has been identified as a potential means of reducing or delaying progression of the symptoms of dementia, maximizing function and independence. The purpose of this study was to explore physical therapists' (PTs) experiences and reflections on facilitating high-intensity functional exercise with older people living with dementia, in residential care home settings. The study used a qualitative design based on interviews, individually or in small groups, with seven PTs engaged as leaders in the training of older people with dementia. The interviews were analyzed with a modified Grounded Theory method with focus on constant comparisons. To increase trustworthiness the study used triangulation within investigators and member checking. The core category "Discover and act in the moment-learn over time" reflects how the PTs continuously developed their own learning in an iterative process. They built on previous knowledge to communicate with residents and staff and to tailor the high intensity training in relation to each individual at that time point. The category "Be on your toes" highlights how the PTs searched for sufficient information about each individual, before and during training, by eliciting the person's current status from staff and by interpreting the person's body language. The category "Build a bond with a palette of strategies" describes the importance of confirmation to build up trust and the use of group members and the room to create an interplay between exercise and social interaction. These findings highlight the continuous iterative process of building on existing knowledge, sharing and reflecting, being alert to any alterations needed for individuals that day, communication skills (both with residents and staff) and building a relationship and trust with residents in the effective delivery of high intensity functional exercise to older people living with dementia in care settings.

Erfolgreiches kognitives Altern: Zusammenhang der kognitiven Leistungen mit Aktivität und Zufriedenheit

Zusammenfassung. Für erfolgreiches Altern sind Kognition, Zufriedenheit und tägliche Aktivitäten relevante Faktoren. In dieser Studie werden Zusammenhänge zwischen diesen Faktoren aufgedeckt. Bei 167 Senioren (60 bis 98 Jahre) wurden Aktivität und Zufriedenheit in einem Interview, Kognition durch die Neuropsychological Assessment Battery (dt. Version) erfasst. Alle Faktoren zeigen eine negative Altersentwicklung. Aktivitäten korrelieren mit allen Faktoren; insbesondere stehen Alltagsaktivitäten und kognitive Aktivitäten positiv mit Kognition im Zusammenhang, soziale Aktivität ist davon unabhängig. Die kognitiven Funktionsbereiche Aufmerksamkeit, Sprache und exekutive Funktionen variieren mit Aktivität und Zufriedenheit, Gedächtnis nur mit kognitiven Aktivitäten, Wahrnehmung ist davon unabhängig. Dies könnte bedeuten, dass kognitive Aktivitäten spezifisch mit der kognitiven Leistung und soziale Aktivitäten spezifisch mit der emotionalen Bewertung zusammenhängen und als Schutzfaktoren während der Entwicklung wirken könnten.

Decreased Physical Activity Associated with Executive Dysfunction Correlates with Cognitive Impairment among Older Adults in the Community: A Retrospective Analysis from the Kurihara Project

BACKGROUND/AIMS

No previous studies have explored the relationship between physical activity (PA) and executive dysfunction.

METHODS

We retrospectively evaluated the PA for 590 older participants in the Kurihara Project; 221 participants had a Clinical Dementia Rating (CDR) of 0 (healthy), 295 CDR 0.5 (very mild dementia), and 74 CDR 1+ (dementia).

RESULTS

In the complicated task, whether the motor intensity was high (e.g. farming) or low (e.g. shopping), PA exhibited an inverse relationship with the CDR level. By contrast, for simple tasks with high intensity (e.g. walking), no CDR group differences were noted. For PA with low intensity (e.g. cleaning), the CDR 1+ group exhibited decreased levels.

CONCLUSION

PA was related to the burden of executive function in patients with mild cognitive impairment; however, in patients with dementia, PA was related to both the burden of executive function and motor intensity.

Effects of Moderate Aerobic Exercise on Cognitive Abilities and Redox State Biomarkers in Older Adults

We used a moderate aerobic exercise program for 24 weeks to measure the positive impact of physical activity on oxidative stress and inflammatory markers and its association with cognitive performance in healthy older adults. A total of 100 healthy subjects (65–95 Yrs) were randomly classified into two groups: control group (n = 50) and exercise group (n = 50). Cognitive functioning, physical activity score, MDA, 8-OHdG, TAC, and hs-CRP were assessed using LOTCA battery, prevalidated PA questionnaire, and immunoassay techniques. LOTCA 7-set scores of cognitive performance showed a significant correlation with physical activity status and the regulation of both oxidative stress free radicals and inflammatory markers in all older subjects following 24 weeks of moderate exercise. Physically active persons showed a higher cognitive performance along with reduction in the levels of MDA, 8-OHdG, and hs-CRP and increase in TAC activity compared with sedentary participants. Cognitive performance correlated positively with the increase in TAC activity and physical fitness scores and negatively with MDA, 8-OHdG, and hs-CRP, respectively. There was a significant improvement in motor praxis, vasomotor organization, thinking operations, and attention and concentration among older adults. In conclusion, moderate aerobic training for 24 weeks has a positive significant effect in improving cognitive functions via modulating redox and inflammatory status of older adults.

Physical Activity and Amyloid-β Brain Levels in Elderly Adults with Intact Cognition and Mild Cognitive Impairment

OBJECTIVES

To examine the associations between amyloid-β brain deposition and physical activity (PA) in elderly adults without dementia and to investigate whether the association has a dose-response relationship.

DESIGN

Cross-sectional study.

SETTING

French community-dwelling people.

PARTICIPANTS

Elderly adults with normal or mildly impaired cognition (mean age 74.7 ± 4.2; 60.4% female) with available information on current self-reported PA and amyloid-β brain deposition measured using positron emission tomography (PET) using the PET-ligand florbetapir F 18 (n = 268).

MEASUREMENTS

A standardized uptake value ratio (SUVR) was obtained for each subject. Participants were divided according to amyloid plaque cortical retention defined according to a SUVR cutoff of 1.10 (SUVR+ vs SUVR-).

RESULTS

Bivariate and multivariate analyses showed that PA was not significantly associated with SUVR. SUVR+ and SUVR- participants did not differ in terms of volume (continuous PA variables) and levels (categorical PA variables) of PA. PA was not correlated with SUVR in apolipoprotein E ε4 carriers or noncarriers. PA was not associated with cognitive function.

CONCLUSION

Although PA protects against dementia, there is no solid evidence that this protection involves a reduction in amyloid-β brain deposition. Further studies are needed to determine whether PA (ideally measured at several time-points using objective measures) is involved in the pathophysiology of Alzheimer's disease.

Cognitive decline and the neighborhood environment

PURPOSE

Little research has looked beyond individual factors to consider the influence of the neighborhood environment on cognitive function. A greater density of physical resources (e.g., recreational centers and parks) and institutional resources (e.g., community centers) may buffer cognitive decline by offering opportunities for physical activity and social interaction.

METHODS

Using data from the Chicago Health and Aging Project (1993-2011), a prospective cohort study of 6518 adults of age 65 years or older, we fit a three-level growth curve model to examine the role of individual and neighborhood factors (objectively observed at the block group level) on trajectories of cognitive function (composite of East Boston Memory Test, symbol digit test, and Mini Mental State Examination) in later life.

RESULTS

Net of individual factors, residence in a neighborhood with community resources, proximity to public transit, and public spaces in good condition were associated with slower rates of cognitive decline, possibly by increasing opportunities for social and physical activities or access to destinations that facilitate engagement in activities.

CONCLUSIONS

These results highlight the role of neighborhood environments in buffering cognitive decline among older adults aging in place.

Cognitive activity relates to cognitive performance but not to Alzheimer disease biomarkers

OBJECTIVE

We aimed to determine whether there was a relationship between lifestyle factors and Alzheimer disease biomarkers.

METHODS

In a cross-sectional study, we evaluated self-reported histories of recent and past cognitive activity, self-reported history of recent physical activity, and objective recent walking activity in 186 clinically normal individuals with mean age of 74 ± 6 years. Using backward elimination general linear models, we tested the hypotheses that greater cognitive or physical activity would be associated with lower Pittsburgh compound B-PET retention, greater (18)F-fluorodeoxyglucose-PET metabolism, and larger hippocampal volume, as well as better cognitive performance on neuropsychological testing.

RESULTS

Linear regression demonstrated that history of greater cognitive activity was correlated with greater estimated IQ and education, as well as better neuropsychological testing performance. Self-reported recent physical activity was related to objective exercise monitoring. However, contrary to hypotheses, we did not find evidence of an association of Pittsburgh compound B retention, (18)F-fluorodeoxyglucose uptake, or hippocampal volume with past or current levels of cognitive activity, or with current physical activity.

CONCLUSIONS

We conclude that a history of lifelong cognitive activity may support better cognitive performance by a mechanism that is independent of brain β-amyloid burden, brain glucose metabolism, or hippocampal volume.

Dietary Patterns Derived by Cluster Analysis are Associated with Cognitive Function among Korean Older Adults

The objective of this study was to investigate major dietary patterns among older Korean adults through cluster analysis and to determine an association between dietary patterns and cognitive function. This is a cross-sectional study. The data from the Korean Multi-Rural Communities Cohort Study was used. Participants included 765 participants aged 60 years and over. A quantitative food frequency questionnaire with 106 items was used to investigate dietary intake. The Korean version of the MMSE-KC (Mini-Mental Status Examination-Korean version) was used to assess cognitive function. Two major dietary patterns were identified using K-means cluster analysis. The "MFDF" dietary pattern indicated high consumption of Multigrain rice, Fish, Dairy products, Fruits and fruit juices, while the "WNC" dietary pattern referred to higher intakes of White rice, Noodles, and Coffee. Means of the total MMSE-KC and orientation score of the participants in the MFDF dietary pattern were higher than those of the WNC dietary pattern. Compared with the WNC dietary pattern, the MFDF dietary pattern showed a lower risk of cognitive impairment after adjusting for covariates (OR 0.64, 95% CI 0.44-0.94). The MFDF dietary pattern, with high consumption of multigrain rice, fish, dairy products, and fruits may be related to better cognition among Korean older adults.

Exercise programs for people with dementia

BACKGROUND

This is an update of our previous 2013 review. Several recent trials and systematic reviews of the impact of exercise on people with dementia are reporting promising findings.

OBJECTIVES

Primary objectiveDo exercise programs for older people with dementia improve their cognition, activities of daily living (ADLs), neuropsychiatric symptoms, depression, and mortality? Secondary objectivesDo exercise programs for older people with dementia have an indirect impact on family caregivers' burden, quality of life, and mortality?Do exercise programs for older people with dementia reduce the use of healthcare services (e.g. visits to the emergency department) by participants and their family caregivers?

SEARCH METHODS

We identified trials for inclusion in the review by searching ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group's Specialised Register, on 4 September 2011, on 13 August 2012, and again on 3 October 2013.

SELECTION CRITERIA

In this review, we included randomized controlled trials in which older people, diagnosed with dementia, were allocated either to exercise programs or to control groups (usual care or social contact/activities) with the aim of improving cognition, ADLs, neuropsychiatric symptoms, depression, and mortality. Secondary outcomes related to the family caregiver(s) and included caregiver burden, quality of life, mortality, and use of healthcare services.

DATA COLLECTION AND ANALYSIS

Independently, at least two authors assessed the retrieved articles for inclusion, assessed methodological quality, and extracted data. We analysed data for summary effects. We calculated mean differences or standardized mean difference (SMD) for continuous data, and synthesized data for each outcome using a fixed-effect model, unless there was substantial heterogeneity between studies, when we used a random-effects model. We planned to explore heterogeneity in relation to severity and type of dementia, and type, frequency, and duration of exercise program. We also evaluated adverse events.

MAIN RESULTS

Seventeen trials with 1067 participants met the inclusion criteria. However, the required data from three included trials and some of the data from a fourth trial were not published and not made available. The included trials were highly heterogeneous in terms of subtype and severity of participants' dementia, and type, duration, and frequency of exercise. Only two trials included participants living at home.Our meta-analysis revealed that there was no clear evidence of benefit from exercise on cognitive functioning. The estimated standardized mean difference between exercise and control groups was 0.43 (95% CI -0.05 to 0.92, P value 0.08; 9 studies, 409 participants). There was very substantial heterogeneity in this analysis (I² value 80%), most of which we were unable to explain, and we rated the quality of this evidence as very low. We found a benefit of exercise programs on the ability of people with dementia to perform ADLs in six trials with 289 participants. The estimated standardized mean difference between exercise and control groups was 0.68 (95% CI 0.08 to 1.27, P value 0.02). However, again we observed considerable unexplained heterogeneity (I² value 77%) in this meta-analysis, and we rated the quality of this evidence as very low. This means that there is a need for caution in interpreting these findings.In further analyses, in one trial we found that the burden experienced by informal caregivers providing care in the home may be reduced when they supervise the participation of the family member with dementia in an exercise program. The mean difference between exercise and control groups was -15.30 (95% CI -24.73 to -5.87; 1 trial, 40 participants; P value 0.001). There was no apparent risk of bias in this study. In addition, there was no clear evidence of benefit from exercise on neuropsychiatric symptoms (MD -0.60, 95% CI -4.22 to 3.02; 1 trial, 110 participants; P value .0.75), or depression (SMD 0.14, 95% CI -0.07 to 0.36; 5 trials, 341 participants; P value 0.16). We could not examine the remaining outcomes, quality of life, mortality, and healthcare costs, as either the appropriate data were not reported, or we did not retrieve trials that examined these outcomes.

AUTHORS' CONCLUSIONS

There is promising evidence that exercise programs may improve the ability to perform ADLs in people with dementia, although some caution is advised in interpreting these findings. The review revealed no evidence of benefit from exercise on cognition, neuropsychiatric symptoms, or depression. There was little or no evidence regarding the remaining outcomes of interest (i.e., mortality, caregiver burden, caregiver quality of life, caregiver mortality, and use of healthcare services).

Does the brain shrink as the waist expands?

Recent studies suggest that being overweight or obese is related to worse cognitive performance, particularly executive function. Obesity may also increase the risk of Alzheimer's disease. Consequently, there has been increasing interest in whether adiposity is related to gray or white matter (GM, WM) atrophy. In this review, we identified and critically evaluated studies assessing obesity and GM or WM volumes either globally or in specific regions of interest (ROIs). Across all ages, higher adiposity was consistently associated with frontal GM atrophy, particularly in prefrontal cortex. In children and adults <40 years of age, most studies found no relationship between adiposity and occipital or parietal GM volumes, whereas findings for temporal lobe were mixed. In middle-aged and aged adults, a majority of studies found that higher adiposity is associated with parietal and temporal GM atrophy, whereas results for precuneus, posterior cingulate, and hippocampus were mixed. Higher adiposity had no clear association with global or regional WM in any age group. We conclude that higher adiposity may be associated with frontal GM atrophy across all ages and parietal and temporal GM atrophy in middle and old age.

Low-intensity daily walking activity is associated with hippocampal volume in older adults

Hippocampal atrophy is associated with memory impairment and dementia and serves as a key biomarker in the preclinical stages of Alzheimer's disease. Physical activity, one of the most promising behavioral interventions to prevent or delay cognitive decline, has been shown to be associated with hippocampal volume; specifically increased aerobic activity and fitness may have a positive effect on the size of the hippocampus. The majority of older adults, however, are sedentary and have difficulty initiating and maintaining exercise programs. A modestly more active lifestyle may nonetheless be beneficial. This study explored whether greater objectively measured daily walking activity was associated with larger hippocampal volume. We additionally explored whether greater low-intensity walking activity, which may be related to leisure-time physical, functional, and social activities, was associated with larger hippocampal volume independent of exercise and higher-intensity walking activity. Segmentation of hippocampal volumes was performed using Functional Magnetic Resonance Imaging of the Brain's Software Library (FSL), and daily walking activity was assessed using a step activity monitor on 92, nondemented, older adult participants. After controlling for age, education, body mass index, cardiovascular disease risk factors, and the Mini Mental State Exam, we found that a greater amount, duration, and frequency of total daily walking activity were each associated with larger hippocampal volume among older women, but not among men. These relationships were specific to hippocampal volume, compared with the thalamus, used as a control brain region, and remained significant for low-intensity walking activity, independent of moderate- to vigorous-intensity activity and self-reported exercise. This is the first study, to our knowledge, to explore the relationship between objectively measured daily walking activity and hippocampal volume in an older adult population. Findings suggest the importance of examining whether increasing nonexercise, lifestyle physical activities may produce measurable cognitive benefits and affect hippocampal volume through molecular pathways unique to those related to moderate-intensity exercise.

Translating the impact of exercise on cognition: methodological issues in animal research

Physical exercise and fitness have been proposed as potential factors that promote healthy cognitive aging. Some of the support for this hypothesis has come from animal research. Animal studies are also used to propose the physiological mechanisms underlying the cognitive performance improvement associated with exercise. In the present review and meta-analysis, we discuss several methodological problems that limit the contribution of animal studies to the understanding of the putative effects of exercise on cognitive aging. We suggest that the most likely measure to equate exercise intensity in rodent and humans may be oxygen consumption (VO2) because observed values are surprisingly similar in young and older rodents and humans. For practical reasons, several animal studies use young rodents kept in social isolation. We show that social isolation is associated with an enhanced impact of exercise on cognitive performance but not on some physiological measures thought to mediate the effect of exercise. Surprisingly, two months or more of exercise intervention appeared to be ineffective to promote cognitive performance compared to shorter durations. We argue that impact of exercise in socially isolated animals is explained by an alleviation of environmental impoverishment as much as an effect of physical exercise. It is possible that the introduction of exercise in rodents is partly mediated by environmental changes. It may explain why larger effects are observed for the shorter durations of exercise while much smaller effects are found after longer periods of exercise.

Perceived Cognitive Impairment among African American elders: health and functional impairments in daily life

OBJECTIVES

The Center for Disease Control began to assess Perceived Cognitive Impairment in 2009, yet there has been no in-depth study of how perceived decline in thinking or memory skills may be associated to the health and lifestyle of an independent community-dwelling older person. Among urban-dwelling older African Americans who are at elevated risk for cognitive impairment and dementia, we know even less regarding the interaction of these risk factors.

METHOD

Five hundred and one African American elders (n=501) between the ages of 55 and 95 with an average age of 70.73 years (SD=8.6 years) participated in telephone interviews.

RESULTS

Approximately one-third of the elders reported that their memory, thinking skills, or ability to reason was worse than a year ago (n=150; 29.9%) and 25% of this group (n=38) reported that this Perceived Cognitive Impairment impacted their daily activities and/or warranted a consultation with their doctor. Bivariate analyses indicated that Perceived Cognitive Impairment was associated with increased health problems, mobility limitations, depressed mood, and lower social functioning.

CONCLUSION

Elders who reported that cognitive problems impacted their daily functioning reported the greatest health and mental health problems. Perceived Cognitive Impairment is an important health variable with implications for an older adult's overall health, mobility, and mental health.

APOE moderates the association between lifestyle activities and cognitive performance: evidence of genetic plasticity in aging

The current study examined independent and interactive effects between Apolipoprotein E (APOE) genotype and two types of cognitively-stimulating lifestyle activities (CSLA)-integrated information processing (CSLA-II) and novel information processing (CSLA-NI)-on concurrent and longitudinal changes in cognition. Three-wave data across 6 years of follow-up from the Victoria Longitudinal Study (n=278; ages 55-94) and linear mixed model analyses were used to characterize the effects of APOE genotype and participation in CSLA-II and CSLA-NI in four cognitive domains. Significant CSLA effects on cognition were observed. More frequent participation in challenging activities (i.e., CSLA-NI) was associated with higher baseline scores on word recall, fact recall, vocabulary and verbal fluency. Conversely, higher participation in less cognitively-challenging activities (i.e., CSLA-II) was associated with lower scores on fact recall and verbal fluency. No longitudinal CSLA-cognition effects were found. Two significant genetic effects were observed. First, APOE moderated CSLA-II and CSLA-NI associations with baseline verbal fluency and fact recall scores. Second, APOE non-ɛ4 carriers' baseline performance were more likely to be moderated by CSLA participation, compared to APOE-ɛ4 carriers. Our findings suggest APOE may be a "plasticity" gene that makes individuals more or less amenable to the influence of protective factors such as CSLA.

Lifestyle engagement affects cognitive status differences and trajectories on executive functions in older adults

The authors first examined the concurrent moderating role of lifestyle engagement on the relation between cognitive status (cognitively elite, cognitively normal [CN], and cognitively impaired [CI]) and executive functioning (EF) in older adults. Second, the authors examined whether baseline participation in lifestyle activities predicted differential 4.5-year stabilities and transitions in cognitive status. Participants (initial N = 501; 53-90 years) were from the Victoria Longitudinal Study. EF was represented by a 1-factor structure. Lifestyle activities were measured in multiple domains of engagement (e.g., cognitive, physical, and social). Two-wave status stability groups included sustained normal aging, transitional early impairment, and chronic impairment. Hierarchical regressions showed that baseline participation in social activities moderated cognitive status differences in EF. CI adults with high (but not low) social engagement performed equivalently to CN adults on EF. Longitudinally, logistic regressions showed that engagement in physical activities was a significant predictor of stability of cognitive status. CI adults who were more engaged in physical activities were more likely to improve in their cognitive status over time than their more sedentary peers. Participation in cognitive activities was a significant predictor of maintenance in a higher cognitive status group. Given that lifestyle engagement plays a detectable role in healthy, normal, and impaired neuropsychological aging, further research in activity-related associations and interventions is recommended.

Exercise programs for people with dementia

BACKGROUND

This is an update of our previous 2008 review. Several recent trials and systematic reviews of the impact of exercise on people with dementia are reporting promising findings. 

OBJECTIVES

Primary: Do exercise programs for older people with dementia improve cognition, activities of daily living (ADLs), challenging behaviour, depression, and mortality in older people with dementia?Secondary: Do exercise programs for older people with dementia have an indirect impact on family caregivers' burden, quality of life, and mortality?Do exercise programs for older people with dementia reduce the use of healthcare services (e.g. visits to the emergency department) by participants and their family caregivers?

SEARCH METHODS

We identified trials for inclusion in the review by searching ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group's Specialised Register, on 4 September 2011, and again on 13 August 2012. The search terms used were: 'physical activity' OR exercise OR cycling OR swim* OR gym* OR walk* OR danc* OR yoga OR 'tai chi'.

SELECTION CRITERIA

In this review, we included randomized controlled trials in which older people, diagnosed with dementia, were allocated either to exercise programs or to control groups (usual care or social contact/activities) with the aim of improving cognition, ADLs, behaviour, depression, and mortality. Secondary outcomes related to the family caregiver(s) and included caregiver burden, quality of life, mortality, and use of healthcare services.

DATA COLLECTION AND ANALYSIS

Independently, at least two authors assessed the retrieved articles for inclusion, assessed methodological quality, and extracted data. Data were analysed for summary effects using RevMan 5.1 software. We calculated mean differences or standardized mean difference (SMD) for continuous data, and synthesized data for each outcome using a fixed-effect model, unless there was substantial heterogeneity between studies, when we used a random-effects model. We planned to explore heterogeneity in relation to severity and type of dementia, and type, frequency, and duration of exercise program. We also evaluated adverse events.

MAIN RESULTS

Sixteen trials with 937 participants met the inclusion criteria. However, the required data from three trials and some of the data from a fourth trial were not published and not made available. The included trials were highly heterogeneous in terms of subtype and severity of participants' dementia, and type, duration and frequency of exercise. Only two trials included participants living at home. Our meta-analysis suggested that exercise programs might have a significant impact on improving cognitive functioning (eight trials, 329 participants; SMD 0.55, 95% confidence interval (CI) 0.02 to 1.09). However, there was substantial heterogeneity between trials (I(2) value 80%), most of which we were unable to explain. We repeated the analysis omitting one trial, an outlier, that included only participants with moderate or severe dementia. This reduced the heterogeneity somewhat (I(2) value 68%), and produced a result that was no longer significant (seven trials, 308 participants; SMD 0.31, 95% CI -0.11 to  0.74). We found a significant effect of exercise programs on the ability of people with dementia to perform ADLs (six studies, 289 participants; SMD 0.68, 95% CI 0.08 to 1.27). However, again we observed considerable unexplained statistical heterogeneity (I(2) value 77%) in this meta-analysis. This means that there is a need for caution in interpreting these findings. In further analyses, we found that the burden experienced by informal caregivers providing care in the home may be reduced when they supervise the participation of the family member with dementia in an exercise program (one study, 40 participants; MD -15.30, 95% CI -24.73 to -5.87), but we found no significant effect of exercise on challenging behaviours (one study, 110 participants; MD -0.60, 95% CI -4.22 to 3.02), or depression (six studies, 341 participants; MD -0.14, 95% CI -0.36 to 0.07) . We could not examine the remaining outcomes, quality of life, mortality, and healthcare costs, as either the appropriate data were not reported, or we did not retrieve trials that examined these outcomes.

AUTHORS' CONCLUSIONS

There is promising evidence that exercise programs can have a significant impact in improving ability to perform ADLs and possibly in improving cognition in people with dementia, although some caution is advised in interpreting these findings. The programs revealed no significant effect on challenging behaviours or depression. There was little or no evidence regarding the remaining outcomes of interest.

Evidence-based risk assessment and recommendations for physical activity clearance: cognitive and psychological conditions

Physical activity has established mental and physical health benefits, but related adverse events have not received attention. The purpose of this paper was to review the documented adverse events occurring from physical activity participation among individuals with psychological or cognitive conditions. Literature was identified through electronic database (e.g., MEDLINE, psychINFO) searching. Studies were eligible if they described a published paper examining the effect of changes on physical activity behaviour, included a diagnosed population with a cognitive or psychological disorder, and reported on the presence or absence of adverse events. Quality of included studies was assessed, and the analyses examined the overall evidence by available subcategories. Forty trials passed the eligibility criteria; these were grouped (not mutually exclusively) by dementia (n = 5), depression (n = 10), anxiety disorders (n = 12), eating disorders (n = 4), psychotic disorders (n = 4), and intellectual disability (n = 15). All studies displayed a possible risk of bias, ranging from moderate to high. The results showed a relatively low prevalence of adverse events. Populations with dementia, psychological disorders, or intellectual disability do not report considerable or consequential adverse events from physical activity independent of associated comorbidities. The one exception to these findings may be Down syndrome populations with atlantoaxial instability; in these cases, additional caution may be required during screening for physical activity. This review, however, highlights the relative paucity of the reported presence or absence of adverse events, and finds that many studies are at high risk of bias toward reporting naturally occurring adverse events.

Lactate administration reproduces specific brain and liver exercise-related changes

The effects of exercise are not limited to muscle, and its ability to mitigate some chronic diseases is under study. A more complete understanding of how exercise impacts non-muscle tissues might facilitate design of clinical trials and exercise mimetics. Here, we focused on lactate's ability to mediate changes in liver and brain bioenergetic-associated parameters. In one group of experiments, C57BL/6 mice underwent 7 weeks of treadmill exercise sessions at intensities intended to exceed the lactate threshold. Over time, the mice dramatically increased their lactate threshold. To ensure that plasma lactate accumulated during the final week, the mice were run to exhaustion. In the liver, mRNA levels of gluconeogenesis-promoting genes increased. While peroxisome proliferator-activated receptor-gamma co-activator 1 alpha (PGC-1α) expression increased, there was a decrease in PGC-1β expression, and overall gene expression changes favored respiratory chain down-regulation. In the brain, PGC-1α and PGC-1β were unchanged, but PGC-1-related co-activator expression and mitochondrial DNA copy number increased. Brain tumor necrosis factor alpha expression fell, whereas vascular endothelial growth factor A expression rose. In another group of experiments, exogenously administered lactate was found to reproduce some but not all of these observed liver and brain changes. Our data suggest that lactate, an exercise byproduct, could mediate some of the effects exercise has on the liver and the brain, and that lactate itself can act as a partial exercise mimetic.

The brain-derived neurotrophic factor Val66Met polymorphism moderates an effect of physical activity on working memory performance

Physical activity enhances cognitive performance, yet individual variability in its effectiveness limits its widespread therapeutic application. Genetic differences might be one source of this variation. For example, carriers of the methionine-specifying (Met) allele of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism have reduced secretion of BDNF and poorer memory, yet physical activity increases BDNF levels. To determine whether the BDNF polymorphism moderated an association of physical activity with cognitive functioning among 1,032 midlife volunteers (mean age = 44.59 years), we evaluated participants' performance on a battery of tests assessing memory, learning, and executive processes, and evaluated their physical activity with the Paffenbarger Physical Activity Questionnaire. BDNF genotype interacted robustly with physical activity to affect working memory, but not other areas of cognitive functioning. In particular, greater levels of physical activity offset a deleterious effect of the Met allele on working memory performance. These findings suggest that physical activity can modulate domain-specific genetic (BDNF) effects on cognition.

A review of multidomain interventions to support healthy cognitive ageing

OBJECTIVE

The risk for cognitive decline and for developing Alzheimer's disease increases with age. The aetiology is assumed to be of multi-factorial origin, and treatment opportunities are lacking. Despite the multi-factorial origin, many intervention studies focused on single factors to influence cognitive health with inconsistent findings. In this view, more and more intervention studies aim to intervene on multiple factors simultaneously to affect or slow down cognitive decline. The purpose of this paper is to give an overview of these multidomain intervention trials.

METHODS

We conducted a non-systematic literature search in Medline, Scopus, Cochrane Library, and clinical trials databases up to October 2011 to review multidomain interventions that investigated effects of combined lifestyle-related factors on cognitive decline and the progression of dementia.

RESULTS

Interest in multidomain interventions increased over the past years. We identified six completed and published trials and eight ongoing or not yet published studies that investigated effects on cognitive outcomes. First completed trials yielded promising results for the combination of exercise and mental training and diet and behavioural weight management. Results of ongoing multidomain trials are awaited.

CONCLUSIONS

Some evidence suggests that strategies which target multiple factors simultaneously may prove more effective than those focusing on a single mechanism or domain. Larger high-quality randomized controlled trials are required to systematically investigate the cognitive effect of programs comprising physical and mental activity as well as nutritional aspects.

Cross-sectional and longitudinal associations of different sedentary behaviors with cognitive performance in older adults

BACKGROUND

The deleterious health effects of sedentary behaviors, independent of physical activity, are increasingly being recognized. However, associations with cognitive performance are not known.

PURPOSE

To estimate the associations between different sedentary behaviors and cognitive performance in healthy older adults.

METHODS

Computer use, time spent watching television (TV), time spent reading and habitual physical activity levels were self-reported twice (in 2001 and 2007) by participants in the SUpplémentation en Vitamines et MinérauX (SU.VI.MAX and SU.VI.MAX2) study. Cognitive performance was assessed at follow-up (in 2007-2009) via a battery of 6 neuropsychological tests used to derive verbal memory and executive functioning scores. Analyses (ANCOVA) were performed among 1425 men and 1154 women aged 65.6 ± 4.5 at the time of the neuropsychological evaluation. We estimated mean differences with 95% confidence intervals (95%CI) in cognitive performance across categories of each type of sedentary behavior.

RESULTS

In multivariable cross-sectional models, compared to non-users, participants using the computer for >1 h/day displayed better verbal memory (mean difference=1.86; 95%CI: 0.95, 2.77) and executive functioning (mean difference=2.15; 95%CI: 1.22, 3.08). A negative association was also observed between TV viewing and executive functioning. Additionally, participants who increased their computer use by more than 30 min between 2001 and 2007 showed better performance on both verbal memory (mean difference=1.41; 95%CI: 0.55, 2.27) and executive functioning (mean difference=1.41; 95%CI: 0.53, 2.28) compared to those who decreased their computer use during that period.

CONCLUSION

Specific sedentary behaviors are differentially associated with cognitive performance. In contrast to TV viewing, regular computer use may help maintain cognitive function during the aging process.

CLINICAL TRIAL REGISTRATION

clinicaltrial.gov (number NCT00272428).

Preventing cognitive decline in older African Americans with mild cognitive impairment: design and methods of a randomized clinical trial

Mild Cognitive Impairment (MCI) affects 25% of older African Americans and predicts progression to Alzheimer's disease. An extensive epidemiologic literature suggests that cognitive, physical, and/or social activities may prevent cognitive decline. We describe the methods of a randomized clinical trial to test the efficacy of Behavior Activation to prevent cognitive decline in older African Americans with the amnestic multiple domain subtype of MCI. Community Health Workers deliver 6 initial in-home treatment sessions over 2-3 months and then 6 subsequent in-home booster sessions using language, materials, and concepts that are culturally relevant to older African Americans during this 24 month clinical trial. We are randomizing 200 subjects who are recruited from churches, senior centers, and medical clinics to Behavior Activation or Supportive Therapy, which controls for attention. The primary outcome is episodic memory as measured by the Hopkins Verbal Learning Test-Revised at baseline and at months 3, 12, 18, and 24. The secondary outcomes are general and domain-specific neuropsychological function, activities of daily living, depression, and quality-of-life. The negative results of recent clinical trials of drug treatments for MCI and Alzheimer's disease suggest that behavioral interventions may provide an alternative treatment approach to preserve cognition in an aging society.

The aging brain and neurodegenerative diseases

This article reviews the current thoughts on the effects of aging on the brain. Mechanisms of neurodegeneration are discussed, particularly those associated with Alzheimer's and Parkinson's diseases. Strategies of early detection of presymptomatic disease and potential future treatments are explored. Modification of risk factors and lifestyles for disease prevention is discussed.

A content analysis of cognitive health promotion in popular magazines

Health behaviors, particularly physical activity, may promote cognitive health. The public agenda for health behaviors is influenced by popular media. We analyzed the cognitive health content of 20 United States magazines, examining every page of every 2006-2007 issue of the highest circulating magazines for general audiences, women, men, African Americans, and the health conscious (n = 178). Diet was the greatest focus. Physical activity coverage was limited. Important behavior-related cognitive health risks, including hypertension and diabetes, were not mentioned. Publications for African Americans had little cognitive health content. Coverage of cognitive health was not commensurate with growing evidence that health behaviors may help to maintain it. Findings may be useful to public health officials, health care providers, non-profit organizations that promote cognitive health, individuals evaluating cognitive health information in popular media, and those responsible for magazines or other media.

The moderating role of exercise on stress-related effects on the hippocampus and memory in later adulthood

OBJECTIVE

Chronic stress has well-documented negative effects on hippocampal structure and function, and has been suggested to contribute to age-related declines. In contrast, there is evidence that exercise has beneficial effects in older adults. The current investigation examined effects of lifetime stress on hippocampal volume and memory, the moderating role of stress on age effects, and the moderating role of exercise on stress-related effects.

METHOD

Measures of lifetime stress, exercise engagement, magnetic-resonance-imaging-based volumes, and cognitive performance were obtained in a sample of healthy middle-aged and older adults.

RESULTS

There was a significant negative influence of stress on hippocampal volume. In addition, exercise engagement moderated effects of lifetime stress on both hippocampal volume and memory. Specifically, lower exercise engagement individuals evidenced greater stress-related declines compared with high exercise engagement individuals.

CONCLUSIONS

These novel findings suggest that benefits of exercise in later adulthood may extend to minimizing detrimental effects of stress on the hippocampus and memory.

Do changes in lifestyle engagement moderate cognitive decline in normal aging? Evidence from the Victoria Longitudinal Study

OBJECTIVE

Do lifestyle activities buffer normal aging-related declines in cognitive performance? The emerging literature will benefit from theoretically broader measurement of both lifestyle activities and cognitive performance, and longer-term longitudinal designs complemented with dynamic statistical analyses. We examine the temporal ordering of changes in lifestyle activities and changes in cognitive neuropsychological performance in older adults.

METHOD

We assembled data (n = 952) across a 12-year (5-wave) period from the Victoria Longitudinal Study. Latent change score models were applied to examine whether (and in which temporal order) changes in physical, social, or cognitive lifestyle activities were related to changes in three domains of cognitive performance.

RESULTS

Two main results reflect the dynamic coupling among changes in lifestyle activities and cognition. First, reductions in cognitive lifestyle activities were associated with subsequent declines in measures of verbal speed, episodic memory, and semantic memory. Second, poorer cognitive functioning was related to subsequent decrements in lifestyle engagement, especially in social activities.

CONCLUSIONS

The results support the dual contention that (a) lifestyle engagement may buffer some of the cognitive changes observed in late life, and (b) persons who are exhibiting poorer cognitive performance may also relinquish some lifestyle activities.

PET amyloid-beta imaging in preclinical Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of dementia, accounting for 60-70% of all cases [Hebert et al., 2003, 1]. The need for effective therapies for AD is great. Current approaches, including cholinesterase inhibitors and N-methyl-d-aspartate (NMDA) receptor antagonists, are symptomatic treatments for AD but do not prevent disease progression. Many diagnostic and therapeutic approaches to AD are currently changing due to the knowledge that underlying pathology starts 10 to 20 years before clinical signs of dementia appear [Holtzman et al., 2011, 2]. New therapies which focus on prevention or delay of the onset or cognitive symptoms are needed. Recent advances in the identification of AD biomarkers now make it possible to detect AD pathology in the preclinical stage of the disease, in cognitively normal (CN) individuals; this biomarker data should be used in the selection of high-risk populations for clinical trials. In vivo visualization of AD neuropathology and biological, biochemical or physiological confirmation of the effects of treatment likely will substantially improve development of novel pharmaceuticals. Positron emission tomography (PET) is the leading neuroimaging tool to detect and provide quantitative measures of AD amyloid pathology in vivo at the early stages and follow its course longitudinally. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.