Relation of cognitive activity to risk of developing Alzheimer disease

Toward defining the preclinical stages of Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease

The pathophysiological process of Alzheimer's disease (AD) is thought to begin many years before the diagnosis of AD dementia. This long "preclinical" phase of AD would provide a critical opportunity for therapeutic intervention; however, we need to further elucidate the link between the pathological cascade of AD and the emergence of clinical symptoms. The National Institute on Aging and the Alzheimer's Association convened an international workgroup to review the biomarker, epidemiological, and neuropsychological evidence, and to develop recommendations to determine the factors which best predict the risk of progression from "normal" cognition to mild cognitive impairment and AD dementia. We propose a conceptual framework and operational research criteria, based on the prevailing scientific evidence to date, to test and refine these models with longitudinal clinical research studies. These recommendations are solely intended for research purposes and do not have any clinical implications at this time. It is hoped that these recommendations will provide a common rubric to advance the study of preclinical AD, and ultimately, aid the field in moving toward earlier intervention at a stage of AD when some disease-modifying therapies may be most efficacious.

Combinations of motor measures more strongly predict adverse health outcomes in old age: the rush memory and aging project, a community-based cohort study

OBJECTIVE

Motor impairment in old age is a growing public-health concern, and several different constructs have been used to identify motor impairments in older people. We tested the hypothesis that combinations of motor constructs more strongly predict adverse health outcomes in older people.

METHODS

In total, 949 people without dementia, history of stroke or Parkinson's disease, who were participating in the Rush Memory and Aging Project (a longitudinal community-based cohort study), underwent assessment at study entry. From this, three constructs were derived: 1) physical frailty based on grip strength, timed walk, body mass index and fatigue; 2) Parkinsonian Signs Score based on the modified motor section of the Unified Parkinson's Disease Rating Scale; and 3) a motor construct, based on nine strength measures and nine motor performances. Disability and cognitive status were assessed annually. A series of Cox proportional-hazards models, controlling for age, sex and education, were used to examine the association of each of these three constructs alone and in various combinations with death, disability and Alzheimer's disease (AD).

RESULTS

All three constructs were related (mean r = 0.50, all P < 0.001), and when considered individually in separate proportional-hazards models, were associated with risk of death, incident disability and AD. However, when considered together, combinations of these constructs more strongly predicted adverse health outcomes.

CONCLUSIONS

Physical frailty, parkinsonian signs score and global motor score are related constructs that capture different aspects of motor function. Assessments using several motor constructs may more accurately identify people at the highest risk of adverse health consequences in old age.

Impaired adaptive cellular responses to oxidative stress and the pathogenesis of Alzheimer's disease

As is generally true with other age-related diseases, Alzheimer's disease (AD) involves oxidative damage to cellular components in the affected tissue, in this case the brain. The causes and consequences of oxidative stress in neurons in AD are not fully understood, but considerable evidence points to important roles for accumulation of amyloid β-peptide upstream of oxidative stress and perturbed cellular Ca(2+) homeostasis and energy metabolism downstream of oxidative stress. The identification of mutations in the β-amyloid precursor protein and presenilin-1 as causes of some cases of early onset inherited AD, and the development of cell culture and animal models based on these mutations has greatly enhanced our understanding of the AD process, and has greatly expanded opportunities for preclinical testing of potential therapeutic interventions. In this regard, and of particular interest to us, is the elucidation of adaptive cellular stress response pathways (ACSRP) that can counteract multiple steps in the AD neurodegenerative cascades, thereby limiting oxidative damage and preserving cognitive function. ACSRP can be activated by factors ranging from exercise and dietary energy restriction, to drugs and phytochemicals. In this article we provide an overview of oxidative stress and AD, with a focus on ACSRP and their potential for preventing and treating AD.

Vulnerability to stress, anxiety, and development of dementia in old age

OBJECTIVE

To identify the components of the neuroticism trait most responsible for its association with cognitive decline and dementia in old age.

DESIGN

Longitudinal clinical-pathologic cohort study.

SETTING

Chicago metropolitan area.

PARTICIPANTS

A total of 785 older persons without dementia completed standard self-report measures of six components of neuroticism and then had annual clinical evaluations for a mean of 3.4 years and brain autopsy in the event of death.

MEASUREMENTS

Incidence of clinically diagnosed Alzheimer disease (AD), change in global and specific cognitive functions, and postmortem measures of plaques and tangles, cerebral infarction, and Lewy bodies.

RESULTS

During follow-up, 94 individuals developed AD. Higher levels of anxiety and vulnerability to stress were associated with increased risk of AD and more rapid decline in global cognition, with no effects for the other four trait components. In analyses of specific cognitive systems, neuroticism subscales were related to decline in episodic memory, working memory, and perceptual speed, but not in semantic memory or visuospatial ability. No component of neuroticism was related to the neuropathologic lesions most commonly associated with late-life dementia.

CONCLUSIONS

Neuroticism's association with late-life dementia mainly reflects vulnerability to stress and anxiety and their correlation with decline in the ability to process and retain new information.

Is dementia preventable? Focus on Alzheimer's disease

The prevention of dementia, and particularly of Alzheimer's disease, is a major challenge for researchers and clinicians. In this article, the mixture of evidence, observations and hypotheses in the current literature is categorized into four avenues for possible preventive interventions, as suggested by the NIH State-of-the-Science Conference. The main categories are: antihypertensive medications; nutrition; cognitive engagement; and physical activity. There is, as yet, no conclusive evidence, but each category may hold promise for the prevention of dementia. The robust findings are as follows: cognitive engagement and regular physical activity may reduce the risk of Alzheimer's disease; the Mediterranean diet and consumption of omega-3 fatty acids deserves further elucidation; and the meticulous management of risk factors, and especially hypertension, is the infrastructure of Alzheimer's disease prevention.

Examining the association between late-life leisure activity participation and global cognitive decline in community-dwelling elderly Chinese in Hong Kong

OBJECTIVE

This study examines the association between late-life leisure activity participation and global cognitive decline in community-dwelling elderly Chinese in Hong Kong.

METHODS

Five hundred and five participants, not clinically demented at the baseline, were analysed in the follow-up study of a population-based community survey among Hong Kong Chinese aged 60 and over. Information regarding leisure activity participation, global cognitive function and important sociodemographic variables was collected. Late life leisure activity profiles were classified into intellectual, social, physical and recreational categories, and were measured by total hours per week, total frequency and total number of subtypes. Multivariate logistic regression analyses were used to evaluate the association between leisure activity participation at the baseline and the incidence of global cognitive decline at the 22-month follow-up. The incidence of global cognitive decline was defined as a one-point drop in z-score of the Cantonese version of the mini-mental state examination (CMMSE).

RESULTS

At the follow-up, a higher level of participation in intellectual activities was significantly associated with a lower incidence of global cognitive decline as measured by both the total hours per week (multivariate-adjusted OR 0.97 (95% CI 0.94-0.99, p=0.003)), and the total number of subtypes (multivariate-adjusted OR 0.74 (95% CI 0.58-0.95, p=0.018)).

CONCLUSIONS

A higher level of late-life intellectual activity participation was associated with less global cognitive decline among community-dwelling elderly Chinese in Hong Kong.

Multisensory stimulation to improve functional performance in moderate to severe dementia--interim results

Dementia is a growing problem worldwide and interventions to effectively manage and promote function are urgently required. Multisensory environments (MSEs) have been used extensively with people with dementia; however, no studies have been conducted to explore the efficacy of sensory stimulation on functional performance. This study explores to what extent multisensory stimulation influences functional performance in people with moderate-to-severe dementia using an MSE compared with a control activity. Thirty participants with moderate-to-severe dementia were recruited from the South of England. Following baseline assessment and design of a bespoke intervention, each participant attended their allocated intervention (3 x week, for 4 weeks). Assessments were carried out pre and postsession using the Assessment of Motor and Process Skills. Results indicate significant improvement in functional performance in both the MSE and the control activity. Findings support the use of MSEs as a strategy for enhancing functional performance in dementia.

Engagement in reading and hobbies and risk of incident dementia: the MoVIES project

OBJECTIVE

To examine whether there is an association between engagement in reading and hobbies and dementia risk in late life.

METHODS

A total of 942 members of a population-based, prospective cohort study were followed biennially to identify incident dementia cases. Cox proportional hazards models were used to estimate the risk of dementia in relation to baseline total number of activities and time commitment to reading and hobbies.

RESULTS

A lower risk for dementia was found for a greater number of activities and for a high (about 1 hour each day) compared with low (less than 30 minutes each day) weekly time commitment to hobbies, independent of covariates. Only the protective effect of hobbies remained after methods were used to minimize bias due to potential preclinical dementia.

CONCLUSION

Engaging in hobbies for 1 or more hours every day might be protective against dementia in late life.

Odor identification and mortality in old age

The association of olfactory dysfunction with mortality was examined in 1162 older persons without dementia or Parkinson's disease. They completed a standard 12-item test of odor identification and then were followed for a mean of 4.2 years (standard deviation [SD] = 2.6, range: 0-9) during which 321 individuals died (27.6%). The relation of olfactory score to risk of death was assessed in a series of proportional hazards models adjusted for age, sex, education, and other covariates. Olfactory scores ranged from 0 to 12 correct (mean = 9.0, SD = 2.2). In an initial analysis, risk of death decreased by about 6% for each additional odor correctly identified (hazard ratio = 0.94; 95% confidence interval: 0.90, 0.98). Thus, mortality risk was about 36% higher with a low score (6, 10th percentile) compared with a high score (11, 90th percentile). The association persisted in subsequent analyses that controlled for naming ability, disability, cerebrovascular disease, characteristic patterns of leisure activity, depressive symptoms, and apolipoprotein E genotype. The results indicate that difficulty identifying familiar odors in old age is associated with increased risk of death.

Cognitive activity and the cognitive morbidity of Alzheimer disease

OBJECTIVE

To test the hypothesis that frequent cognitive activity predicts slower cognitive decline before dementia onset in Alzheimer disease (AD) and faster decline thereafter.

METHODS

As part of a longitudinal cohort study, older residents of a geographically defined population were assessed at 3-year intervals with brief cognitive performance tests from which a composite measure of global cognition was derived. After each wave of testing, a subset was sampled for clinical evaluation. The present analyses are based on 1,157 participants. They were free of dementia at study enrollment at which time they rated frequency of participation in common cognitively stimulating activities from which a previously validated summary measure was derived. They were sampled for clinical evaluation a mean of 5.6 years after enrollment and subsequently followed a mean of 5.7 years with brief cognitive performance testing at 3-year intervals.

RESULTS

On clinical evaluation, 614 people had no cognitive impairment, 395 had mild cognitive impairment, and 148 had AD. During follow-up, the annual rate of global cognitive decline in persons without cognitive impairment was reduced by 52% (estimate = 0.029, SE = 0.010, p = 0.003) for each additional point on the cognitive activity scale. In the mild cognitive impairment group, cognitive decline rate was unrelated to cognitive activity (estimate = -0.019, SE = 0.018, p = 0.300). In AD, the mean rate of decline per year increased by 42% (estimate = 0.075, SE = 0.021, p < 0.001) for each point on the cognitive activity scale.

CONCLUSION

Mentally stimulating activity in old age appears to compress the cognitive morbidity associated with AD by slowing cognitive decline before dementia onset and hastening it thereafter.

Prevention of dementia: focus on lifestyle

The objective of this paper is to summarize current knowledge on the possible advantages of lifestyle interventions, with particular attention to physical fitness, cognitive activity, leisure and social activity as well as nutrition. There is a large amount of published papers providing partial evidence and asserting the need for immediate, appropriate preventive lifestyle measures against dementia and AD development. Nevertheless, there are currently great difficulties in drafting effective guidelines in this field. This depends mainly upon lack of randomized controlled trials assessing benefits versus risks of particular lifestyle interventions strategies. However, due to the rapid increase of dementia burden, lifestyle factors and their amelioration should be already made part of decision making in light of their health-maintaining effects while awaiting for results of well-designed large prospective cohort studies in dementia.

Dementia risk factors for Australian baby boomers

Baby boomers are individuals born in the years 1946 to 1965. The objective of this paper was to define the risk factors for dementia and Alzheimer’s disease (AD) and their relevance to Australian baby boomers, with the aim of providing evidence-based guidelines for dementia prevention. A series of PubMed searches (1994–2010) were conducted with relevant key words. Data was included from the Australian Bureau of Statistics (ABS) in relation to baby boomers in Australia. Article titles and abstracts were assessed by two reviewers for inclusion. Searches through ABS revealed no specific study on baby boomers at a national level; information was only available for Western Australia, South Australia and Queensland. A number of genetic and non-genetic risk factors for dementia were identified most of which remain controversial and require further study. We did not identify significant differences in the prevalence and incidence of dementia in those under 65 years in Queensland, South Australia and Western Australia. There were no correlations of risk factors and dementia between the Australian states. Modification of risk factors has not been proven to reduce the incidence and prevalence of dementia and AD in baby boomers. Nevertheless, on available evidence, we recommend: i) active management of cardiovascular risk factors such as hypertension; ii) the encouragement of a healthy lifestyle (eg, weight reduction, exercise) as offering the best pathways to reduce the emerging dementia risk for baby boomers. The implications are that activities promoting a healthy heart might lead to a healthy brain and help to prevent dementia.

Examining the association between participation in late-life leisure activities and cognitive function in community-dwelling elderly Chinese in Hong Kong

BACKGROUND

Growing evidence suggests that participation in late-life leisure activity may have beneficial effects on cognitive function. The objective of the study was to evaluate the association between leisure activity participation and cognitive function in an elderly population of community-dwelling Hong Kong Chinese.

METHODS

512 participants were assessed in the follow-up study of a population-based community survey of the prevalence of cognitive impairment among Hong Kong Chinese aged 60 years and over. Leisure activities were classified into four categories (physical, intellectual, social and recreational). Information regarding leisure activity participation, cognitive function and other variables was collected. Multivariate linear regression analyses were performed to examine the association between leisure activity participation and cognitive function.

RESULTS

A higher level of late-life leisure activity participation, particularly in intellectual activities, was significantly associated with better cognitive function in the elderly, as reflected by the results of the Cantonese Mini-mental State Examination (p = 0.007, 0.029 and 0.005), the Category Verbal Fluency Test (p = 0.027, 0.003 and 0.005) and digit backward span (p = 0.031, 0.002 and 0.009), as measured by the total frequency, total hours per week and total number of subtypes, respectively; the Chinese Alzheimer's Disease Assessment Scale-Cognitive Subscale (p = 0.045) and word list learning (p = 0.003), as measured by the total number of subtypes; and digit forward span (p = 0.007 and 0.015), as measured by the total hours per week and total number of subtypes, respectively.

CONCLUSION

Late-life intellectual activity participation was associated with better cognitive function among community-dwelling Hong Kong elderly Chinese.

Promotion of cognitive health through cognitive activity in the aging population

There is both popular and scientific interest in keeping the brain young and avoiding cognitive impairment and dementia. Older adults may be able to modify their cognitive health status through certain health behaviors. The aim of this review is to highlight the potential impact that cognitive activity may have on cognitive health outcomes in late life. Evidence from observational studies and randomized, controlled trials suggests that engagement in activities that are cognitively stimulating is beneficial to cognitive functioning. There are many issues and questions that need to be addressed before specific recommendations can be made at the population level or to individual patients. However, older adults should be encouraged to stay active and to try new and challenging activities in general to promote their cognitive and overall health.

The paradox of cognitive change

Properties of cognitive change scores were compared in adults over age 70, for whom longitudinal changes are often negative, and in adults in two age groups under age 70, for whom the changes are often close to zero. Longitudinal assessments of three measures of memory and three measures of speed across an average interval of 2.4 years were obtained from a sample of 1,282 healthy adults between 18 and 92 years of age. Although substantial longitudinal declines were primarily apparent in adults 70 years of age and older, adults under and over age 70 were similar with respect to the variability and reliability of the cognitive changes, and in the magnitude of the correlations of the changes with each other and with variables that have been identified as risk factors for late-life cognitive decline and dementia. It is suggested that longitudinal changes in cognition can be considered to represent a paradox in that the mean values of the changes are more negative at older ages, but the change scores have similar measurement properties, and appear to be just as systematic, among adults under and over 70 years of age.

Intellectual enrichment is linked to cerebral efficiency in multiple sclerosis: functional magnetic resonance imaging evidence for cognitive reserve

The cognitive reserve hypothesis helps to explain the incomplete relationship between brain disease and cognitive status in people with neurologic diseases, including Alzheimer's; disease and multiple sclerosis. Lifetime intellectual enrichment (estimated with education or vocabulary knowledge) lessens the negative impact of brain disease on cognition, such that people with greater enrichment are able to withstand more severe neuropathology before suffering cognitive impairment or dementia. The current research is the first to investigate directly the relationship between intellectual enrichment and an index of cerebral activity (the blood oxygen level dependent signal) in a neurologic sample. Multiple sclerosis patients completed a vocabulary-based estimate of lifetime intellectual enrichment. Disease severity was estimated with brain atrophy. Cognitive status was measured with the Symbol Digit Modalities Test. Cerebral activity (functional magnetic resonance imaging blood oxygen level dependent signal) and behavioural performance (accuracy, reaction time) were recorded during the visual N-Back working memory task (three levels of demand: 0-, 1-, 2-Back). All patients produced perfect/nearly perfect accuracy during lower demands (0- and 1-Back), and reaction time was unrelated to intellectual enrichment; however, voxelwise partial correlations controlling for brain atrophy revealed strong positive correlations between intellectual enrichment and cerebral activity within the brain's; default network (e.g. anterior and posterior cingulate corticies), indicating that patients with greater enrichment were able to maintain resting state activity during cognitive processing better. In turn, intellectual enrichment was negatively associated with prefrontal recruitment, suggesting that patients with lesser enrichment required more cerebral resources to perform the same cognitive task as patients with greater enrichment. This same pattern of enrichment-related cerebral activity was observed when cognitive demands increased (2-Back), and intellectual enrichment was negatively associated with reaction time. Principle components analysis revealed a single cognitive reserve network across tasks (greater default network, lesser prefrontal recruitment). Expression of this network almost fully mediated the positive relationship between intellectual enrichment and cognitive status (Symbol Digit Modalities Test). Also, expression of this network was positively associated with brain atrophy when controlling for cognitive status, indicating that patients with greater expression of this network can withstand more severe brain disease before exhibiting cognition similar to patients with lesser network expression. Of note, similar functional magnetic resonance imaging research with healthy adults has not found an association between intelligence and cerebral efficiency. The unique relationship between intellectual enrichment and cerebral efficiency in neurologic patients is consistent with the cognitive reserve hypothesis, which does not posit that enrichment leads to gains in neurocognitive functioning per se; rather, enrichment protects against neurocognitive decline secondarily to disease.

Early risk assessment for Alzheimer's disease

The purpose of the Alzheimer's Association Research Roundtable meeting was to discuss the potential of finding diagnostic tools to determine the earliest risk factors for Alzheimer's disease (AD). Currently, drugs approved for AD address symptoms which are generally manifest after the disease is already well-established, but there is a growing pipeline of drugs that may alter the underlying pathology and therefore slow or halt progression of the disease. As these drugs become available, it will become increasingly imperative that those at risk for AD be detected and possibly treated early, especially given recent indications that the disease process may start decades before the first clinical symptoms are recognized. Early detection must go hand-in-hand with qualified tools to determine the efficacy of drugs in people who may be asymptomatic or who have only very mild symptoms of the disease. Devising strategies and screening tools to identify and monitor those at risk in order to perform "prevention" trials is seen by many as a top public-health priority, made all the more urgent by an impending growth in the elderly population worldwide.

Uncontrolled diabetes increases the risk of Alzheimer's disease: a population-based cohort study

AIMS/HYPOTHESIS

Diabetes has been related to Alzheimer's disease with inconsistent findings. We aimed to clarify the association of diabetes with different dementing disorders taking into account glycaemic control, and to explore the link between glucose dysregulation and neurodegeneration.

METHODS

A dementia-free cohort (n = 1,248) aged >or=75 years was longitudinally examined to detect dementia, Alzheimer's disease and vascular dementia (VaD) cases (Diagnostic and Statistical Manual of Mental Disorders, revised third edition [DSM-III-R] criteria). The Alzheimer's disease diagnoses were subdivided into Alzheimer's disease with stroke and Alzheimer's disease without hypertension, heart disease and stroke. Diabetes was ascertained based on medical history, or hypoglycaemic medication use, or a random blood glucose level >or=11.0 mmol/l, which included undiagnosed diabetes when neither a history of diabetes nor hypoglycaemic drugs use was present. Uncontrolled diabetes was classified as a random blood glucose level >or=11.0 mmol/l in diabetic patients. Borderline diabetes was defined as a random blood glucose level of 7.8-11.0 mmol/l in diabetes-free individuals. Cox models were used to estimate HRs.

RESULTS

During the 9 year follow-up, 420 individuals developed dementia, including 47 with VaD and 320 with Alzheimer's disease (of the 320 Alzheimer's disease cases, 78 had previous, temporally unrelated stroke, and 137 had no major vascular comorbidities). Overall diabetes was only related to VaD (HR 3.21, 95% CI 1.20-8.63). Undiagnosed diabetes led to an HR of 3.29 (95% CI 1.20-9.01) for Alzheimer's disease. Diabetic patients with random blood glucose levels <7.8 mmol/l showed no increased dementia risk. Uncontrolled and borderline diabetes were further associated with Alzheimer's disease without vascular comorbidities.

CONCLUSIONS/INTERPRETATION

Uncontrolled diabetes increases the risk of Alzheimer's disease and VaD. Our findings suggest a direct link between glucose dysregulation and neurodegeneration.

Modifiable Midlife Risk Factors for Late-Life Cognitive Impairment and Dementia

The baby boom generation is approaching the age of greatest risk for cognitive impairment and dementia. There is growing interest in strategies to modify the environment in midlife to increase the probability of maintaining cognitive health in late life. Several potentially modifiable risk factors have been studied in relation to cognitive impairment and dementia in late life, but methodological limitations of observational research have resulted in some inconsistencies across studies. The most promising strategies are maintaining cardiovascular health, engagement in mental, physical, and social activities, using alcohol in moderation, abstaining from tobacco use, and following a heart-healthy diet. Other factors that may influence cognitive health are occupational attainment, depression, personality, exposure to general anesthesia, head injury, postmenopausal hormone therapy, non-steroidal anti-inflammatory medications, and nutritional supplements such as antioxidants. Some long-term observational studies initiated in midlife or earlier, and some randomized controlled trials, have examined the effects of specific cognitive health promotion behaviors in midlife on the risk of cognitive impairment in late life. Overall, these studies provide limited support for risk reduction at this time. Recommendations and challenges for developing effective strategies to reduce the burden of cognitive impairment and dementia in the future are discussed.

A cognitive training program based on principles of brain plasticity: results from the Improvement in Memory with Plasticity-based Adaptive Cognitive Training (IMPACT) study

OBJECTIVES

To investigate the efficacy of a novel brain plasticity-based computerized cognitive training program in older adults and to evaluate the effect on untrained measures of memory and attention and participant-reported outcomes.

DESIGN

Multisite randomized controlled double-blind trial with two treatment groups.

SETTING

Communities in northern and southern California and Minnesota.

PARTICIPANTS

Community-dwelling adults aged 65 and older (N=487) without a diagnosis of clinically significant cognitive impairment.

INTERVENTION

Participants were randomized to receive a broadly-available brain plasticity-based computerized cognitive training program (intervention) or a novelty- and intensity-matched general cognitive stimulation program modeling treatment as usual (active control). Duration of training was 1 hour per day, 5 days per week, for 8 weeks, for a total of 40 hours.

MEASUREMENTS

The primary outcome was a composite score calculated from six subtests of the Repeatable Battery for the Assessment of Neuropsychological Status that use the auditory modality (RBANS Auditory Memory/Attention). Secondary measures were derived from performance on the experimental program, standardized neuropsychological assessments of memory and attention, and participant-reported outcomes.

RESULTS

RBANS Auditory Memory/Attention improvement was significantly greater (P=.02) in the experimental group (3.9 points, 95% confidence interval (CI)=2.7-5.1) than in the control group (1.8 points, 95% CI=0.6-3.0). Multiple secondary measures of memory and attention showed significantly greater improvements in the experimental group (word list total score, word list delayed recall, digits backwards, letter-number sequencing; P<.05), as did the participant-reported outcome measure (P=.001). No advantage for the experimental group was seen in narrative memory.

CONCLUSION

The experimental program improved generalized measures of memory and attention more than an active control program.

Social engagement and cognitive function in old age

We examined the association of diverse measures of social engagement with level of function in multiple cognitive domains in 838 persons without dementia who had a mean age of 80.2 (SD = 7.5). Social network size, frequency of social activity, and level of perceived social support were assessed in linear regression models adjusted for age, sex, education, and other covariates. Social activity and social support were related to better cognitive function, whereas social network size was not strongly related to global cognition. The results confirm that higher level of social engagement in old age is associated with better cognitive function but the association varies across domains of social engagement.

[Activities in retired people and the risk of dementia]

It is necessary to develop the prevention of Alzheimer's disease, because of the increase in the number of cases and unavailability of a curative treatment. From the data of the cohort PAQUID, we studied the risk of dementia according to leisure activities and the age of cessation of professional activity. The practice of a sport and reading decreases by 25% the risk of dementia during 15 years. The age of cessation of professional activity is not associated with the risk of dementia. An active life seems to be a possible way to prevent dementia.

Cognitive leisure activities and their role in preventing dementia: a systematic review

BACKGROUND

Dementia is a debilitating syndrome that inflicts a tremendous burden of care on one's family, individual caregivers, health care professionals and on the use of resources. Existing therapeutic interventions can only help control or reduce symptoms, and slow the disease's progression. Identifying protective factors or effective prevention strategies would result in considerable benefits. Participation in cognitive leisure activities has been implicated as a possible prevention strategy.

OBJECTIVE

The objective of the review was to establish best practice in relation to cognitive leisure activities in preventing dementia among older adults.

INCLUSION CRITERIA

Randomised controlled trials (RCTs), other experimental studies, cohort studies, case-controlled studies and cross-sectional studies were considered for the review.Participants of interest were adults aged 60 years and older with or without a clinical diagnosis of dementia, living in the community or residential care setting.The review focussed on any cognitive leisure activity that required a mental response from the individual taking part in the activity e.g. reading and playing board games.The primary outcome of the review was the presence or absence of dementia, determined by cognitive function tests, mental examination scores, DSM classification (Diagnostic and Statistical Manual of Mental Disorders), and other valid dementia diagnostic tools.

SEARCH STRATEGY

A search for published and unpublished literature in the English language was conducted using all major electronic databases. There was no publication date restriction. A three-step search strategy was developed using MeSH terminology and keywords to ensure that all material relevant to the review was captured.

ASSESSMENT OF QUALITY

The methodological quality of included studies was assessed by two reviewers, who appraised each study independently, using standard Joanna Briggs Institute (JBI) critical appraisal tools.

DATA COLLECTION AND ANALYSIS

Data was extracted from the studies that were identified as meeting the criteria for methodological quality using the standard JBI data extraction tools. Due to the heterogeneity of populations and interventions, meta-analyses were not possible and results are presented in narrative form.

RESULTS

Thirteen longitudinal studies were included in the review. Studies were grouped by stage of adult life participation when interventions were undertaken i.e. early-middle adulthood and late life. Five out of six studies demonstrated a positive association between engagement in activities and a reduced risk of developing Alzheimer's disease (AD) when interventions were undertaken in middle adulthood and six out of seven studies produced a positive association for late life participation. Results indicated that some activities might be more beneficial than others.Actively participating in cognitive leisure activities during mid or late life may be beneficial in preventing the risk of dementia in the elderly however the evidence is currently not strong enough to infer a direct causal relationship.Participating in selected cognitive leisure activities may be more favourable than others but currently there is no strong evidence to recommend one over the other.

Physical frailty in older persons is associated with Alzheimer disease pathology

OBJECTIVE

We examined the extent to which physical frailty in older persons is associated with common age-related brain pathology, including cerebral infarcts, Lewy body pathology, and Alzheimer disease (AD) pathology.

METHODS

We studied brain autopsies from 165 deceased participants from the Rush Memory and Aging Project, a longitudinal clinical-pathologic study of aging. Physical frailty, based on four components, including grip strength, time to walk 8 feet, body composition, and fatigue, was assessed at annual clinical evaluations. Multiple regression analyses were used to examine the relation of postmortem neuropathologic findings to frailty proximate to death, controlling for age, sex, and education.

RESULTS

The mean age at death was 88.1 years (SD = 5.7 years). The level of AD pathology was associated with frailty proximate to death ( = 0.252, SE = 0.077, p = 0.001), accounting for 4% of the variance of physical frailty. Neither cerebral infarcts ( = -0.121, SE = 0.115, p = 0.294) nor Lewy body disease pathology ( = 0.07, SE = 0.156, p = 0.678) was associated with frailty. These associations were unchanged after controlling for the time interval from last clinical evaluation to autopsy. The association of AD pathology with frailty did not differ by the presence of dementia, and this association was unchanged even after considering potential confounders, including physical activity; parkinsonian signs; pulmonary function; or history of chronic diseases, including vascular risk factors, vascular disease burden, falls, joint pain, or use of antipsychotic or antihypertensive medications.

CONCLUSION

Physical frailty in old age is associated with Alzheimer disease pathology in older persons with and without dementia.

Enrichment Effects on Adult Cognitive Development: Can the Functional Capacity of Older Adults Be Preserved and Enhanced?

In this monograph, we ask whether various kinds of intellectual, physical, and social activities produce cognitive enrichment effects-that is, whether they improve cognitive performance at different points of the adult life span, with a particular emphasis on old age. We begin with a theoretical framework that emphasizes the potential of behavior to influence levels of cognitive functioning. According to this framework, the undeniable presence of age-related decline in cognition does not invalidate the view that behavior can enhance cognitive functioning. Instead, the course of normal aging shapes a zone of possible functioning, which reflects person-specific endowments and age-related constraints. Individuals influence whether they function in the higher or lower ranges of this zone by engaging in or refraining from beneficial intellectual, physical, and social activities. From this point of view, the potential for positive change, or plasticity, is maintained in adult cognition. It is an argument that is supported by newer research in neuroscience showing neural plasticity in various aspects of central nervous system functioning, neurochemistry, and architecture. This view of human potential contrasts with static conceptions of cognition in old age, according to which decline in abilities is fixed and individuals cannot slow its course. Furthermore, any understanding of cognition as it occurs in everyday life must make a distinction between basic cognitive mechanisms and skills (such as working-memory capacity) and the functional use of cognition to achieve goals in specific situations. In practice, knowledge and expertise are critical for effective functioning, and the available evidence suggests that older adults effectively employ specific knowledge and expertise and can gain new knowledge when it is required. We conclude that, on balance, the available evidence favors the hypothesis that maintaining an intellectually engaged and physically active lifestyle promotes successful cognitive aging. First, cognitive-training studies have demonstrated that older adults can improve cognitive functioning when provided with intensive training in strategies that promote thinking and remembering. The early training literature suggested little transfer of function from specifically trained skills to new cognitive tasks; learning was highly specific to the cognitive processes targeted by training. Recently, however, a new generation of studies suggests that providing structured experience in situations demanding executive coordination of skills-such as complex video games, task-switching paradigms, and divided attention tasks-train strategic control over cognition that does show transfer to different task environments. These studies suggest that there is considerable reserve potential in older adults' cognition that can be enhanced through training. Second, a considerable number of studies indicate that maintaining a lifestyle that is intellectually stimulating predicts better maintenance of cognitive skills and is associated with a reduced risk of developing Alzheimer's disease in late life. Our review focuses on longitudinal evidence of a connection between an active lifestyle and enhanced cognition, because such evidence admits fewer rival explanations of observed effects (or lack of effects) than does cross-sectional evidence. The longitudinal evidence consistently shows that engaging in intellectually stimulating activities is associated with better cognitive functioning at later points in time. Other studies show that meaningful social engagement is also predictive of better maintenance of cognitive functioning in old age. These longitudinal findings are also open to important rival explanations, but overall, the available evidence suggests that activities can postpone decline, attenuate decline, or provide prosthetic benefit in the face of normative cognitive decline, while at the same time indicating that late-life cognitive changes can result in curtailment of activities. Given the complexity of the dynamic reciprocal relationships between stimulating activities and cognitive function in old age, additional research will be needed to address the extent to which observed effects validate a causal influence of an intellectually engaged lifestyle on cognition. Nevertheless, the hypothesis that an active lifestyle that requires cognitive effort has long-term benefits for older adults' cognition is at least consistent with the available data. Furthermore, new intervention research that involves multimodal interventions focusing on goal-directed action requiring cognition (such as reading to children) and social interaction will help to address whether an active lifestyle enhances cognitive function. Third, there is a parallel literature suggesting that physical activity, and aerobic exercise in particular, enhances older adults' cognitive function. Unlike the literature on an active lifestyle, there is already an impressive array of work with humans and animal populations showing that exercise interventions have substantial benefits for cognitive function, particularly for aspects of fluid intelligence and executive function. Recent neuroscience research on this topic indicates that exercise has substantial effects on brain morphology and function, representing a plausible brain substrate for the observed effects of aerobic exercise and other activities on cognition. Our review identifies a number of areas where additional research is needed to address critical questions. For example, there is considerable epidemiological evidence that stress and chronic psychological distress are negatively associated with changes in cognition. In contrast, less is known about how positive attributes, such as self-efficacy, a sense of control, and a sense of meaning in life, might contribute to preservation of cognitive function in old age. It is well known that certain personality characteristics such as conscientiousness predict adherence to an exercise regimen, but we do not know whether these attributes are also relevant to predicting maintenance of cognitive function or effective compensation for cognitive decline when it occurs. Likewise, more information is needed on the factors that encourage maintenance of an active lifestyle in old age in the face of elevated risk for physiological decline, mechanical wear and tear on the body, and incidence of diseases with disabling consequences, and whether efforts to maintain an active lifestyle are associated with successful aging, both in terms of cognitive function and psychological and emotional well-being. We also discuss briefly some interesting issues for society and public policy regarding cognitive-enrichment effects. For example, should efforts to enhance cognitive function be included as part of a general prevention model for enhancing health and vitality in old age? We also comment on the recent trend of business marketing interventions claimed to build brain power and prevent age-related cognitive decline, and the desirability of direct research evidence to back claims of effectiveness for specific products.

Prevention of progression to dementia in the elderly: rationale and proposal for a health-promoting memory consultation (an IANA Task Force)

Alzheimer's disease (AD) is the most frequent form of dementia and according to the most recent estimation it affects nearly 27 million people in the world. The onset of the disease is generally insidious. It is becoming increasingly evident that the underlying pathophysiological mechanisms are active long before the appearance of the clinical symptoms of the disease. In the current context, it is important to develop strategies to delay the onset of cognitive decline. Delaying the onset by 5 years would reduce the prevalence by half at term, and a delay of 10 years would reduce it by three-quarters. The effectiveness of currently suggested preventive approaches remains to be confirmed, but certain strategies could be applied straight away to at-risk subjects. We propose that a health-promoting memory consultation should be set up for elderly persons who have attended a specialized memory consultation and in whom the diagnosis of dementia and of AD in particular, has not been established by standardized tools. Through this consultation, they would be offered full multidimensional investigation of all aspects of their health status, follow-up could be organized, general practitioners in private practice could be made more conscious of this population and the elderly could be made more aware of the risk factors to which they are exposed. The development of an information policy for the elderly would meet a present need. In our reflection, we must take into account the question of how to give this preventive consultation its due place in the healthcare pathway of the elderly person in order to ensure coordinated follow-up with all the other health professionals involved. The principle of the health-promoting memory consultation is undergoing validation in a large French multicentre preventive trial in 1200 frail elderly persons aged 70 years followed for three years, the Multidomain Alzheimer Preventive Trial (MAPT).

Mind games: do they work?

Last week a government report highlighted that the number of people in England with dementia is set to rise by 30% over the next 15 years. James Butcher investigates whether programs such as Nintendo’s Brain Age, which claims to improve cognitive function, could help elderly users