Relation of cognitive activity to risk of developing Alzheimer disease

Religious Orders Study and Rush Memory and Aging Project

BACKGROUND

The Religious Orders Study and Rush Memory and Aging Project are both ongoing longitudinal clinical-pathologic cohort studies of aging and Alzheimer's disease (AD).

OBJECTIVES

To summarize progress over the past five years and its implications for understanding neurodegenerative diseases.

METHODS

Participants in both studies are older adults who enroll without dementia and agree to detailed longitudinal clinical evaluations and organ donation. The last review summarized findings through the end of 2011. Here we summarize progress and study findings over the past five years and discuss new directions for how these studies can inform on aging and AD in the future.

RESULTS

We summarize 1) findings on the relation of neurobiology to clinical AD; 2) neurobiologic pathways linking risk factors to clinical AD; 3) non-cognitive AD phenotypes including motor function and decision making; 4) the development of a novel drug discovery platform.

CONCLUSION

Complexity at multiple levels needs to be understood and overcome to develop effective treatments and preventions for cognitive decline and AD dementia.

Grandparent Caregiving, Race, and Cognitive Functioning in a Population-Based Sample of Older Adults

Objective: The aim of this study was to evaluate the association between noncustodial grandparent caregiving and cognition using the Health and Retirement Study (HRS), a population-based study of older adults. Method: Participants were White and African American grandparents aged ≥65 years. Only noncustodial grandparents who reported not living with their grandchildren over the three waves were included in our analyses. Grandparent caregiving status and cognition were assessed in 2006, 2008, and 2010. Analyses controlled for demographics, baseline health, depressive symptoms, and baseline cognition. Results: Both the number of waves of grandparent caregiving and the total number of grandparent caregiving hours across the three waves were associated with better cognitive functioning at 4-year follow-up in 2010. Associations were observed among Whites, but not among African Americans. Discussion: This study uses longitudinal data to evaluate the association between grandparent caregiving and cognitive functioning. Findings suggest that providing care may be beneficial for some grandparents.

Cognitive activity, cognitive function, and brain diffusion characteristics in old age

The objective of this work was to test the hypotheses that a) more frequent cognitive activity in late life is associated with higher brain diffusion anisotropy and lower trace of the diffusion tensor, and b) brain diffusion characteristics partially mediate the association of late life cognitive activity with cognition. As part of a longitudinal cohort study, 379 older people without dementia rated their frequency of participation in cognitive activities, completed a battery of cognitive function tests, and underwent diffusion tensor imaging. We used tract-based spatial statistics to test the association between late life cognitive activity and brain diffusion characteristics. Clusters with statistically significant findings defined regions of interest in which we tested the hypothesis that diffusion characteristics partially mediate the association of late life cognitive activity with cognition. More frequent cognitive activity in late life was associated with higher level of global cognition after adjustment for age, sex, education, and indicators of early life cognitive enrichment (p = 0.001). More frequent cognitive activity was also related to higher fractional anisotropy in the left superior and inferior longitudinal fasciculi, left fornix, and corpus callosum, and lower trace in the thalamus (p < 0.05, FWE-corrected). After controlling for fractional anisotropy or trace from these regions, the regression coefficient for the association of late life cognitive activity with cognition was reduced by as much as 26 %. These findings suggest that the association of late life cognitive activity with cognition may be partially mediated by brain diffusion characteristics.

Continuing education for the prevention of mild cognitive impairment and Alzheimer's-type dementia: a systematic review protocol

BACKGROUND

Because of the enormous social and economic burden of disease, the prevention of mild cognitive impairment and Alzheimer's-type dementia has become a major global public health priority. Studies show that cognitively stimulating activities during middle adulthood might have a protective effect on the brain by boosting the cognitive reserve. The aim of this review is to identify evidence investigating the effects of continuing education for the prevention of mild cognitive impairment and Alzheimer's-type dementia in late life.

METHODS

Our approach employs a two-stage design: First, we will conduct a systematic review to assess the preventive effects of continuing education on mild cognitive impairment and Alzheimer's-type dementia. Second, because we expect to find few studies, we will perform a review of systematic reviews on leisure activities that mimic formal continuing education to determine their effects on the prevention of mild cognitive impairment and Alzheimer's-type dementia. We will search electronic databases (e.g., MEDLINE, PsycINFO, EMBASE, CENTRAL, CINAHL, and Scopus) for published studies and gray literature databases (e.g., trial registries) for unpublished studies. Two authors will independently screen abstracts and full-texts using pre-defined eligibility criteria, select studies, extract data, and assess the quality of included studies or reviews. Outcomes of interest include the incidence of mild cognitive impairment or Alzheimer's-type dementia, quality of life, functional capacity, and psychological wellbeing. Intermediate outcomes are cognitive (test) performance, cognitive functioning, and social inclusion. The review team is a multidisciplinary group consisting of methodological experts and dementia, geriatrics, and continuing education researchers.

DISCUSSION

We anticipate that our review will highlight serious gaps in the current evidence. Results will build the basis for further research regarding the relation of continuing education and cognitive decline and dementia.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017063944.

Lifestyle factors and Alzheimer's disease in people with Down syndrome

BACKGROUND

Lifestyle has previously been associated with the onset of Alzheimer's disease (AD) in the typically developing population, but research investigating this association in Down syndrome (DS) is limited.

METHOD

Adults with DS and AD (n = 27) were compared to adults with DS without AD (n = 30) on physical activity, diet, weight, where participants currently lived, where participants had lived for the majority of their lives, educational attainment, occupational attainment and cognitive activity.

RESULTS

There was a significant difference between samples on where participants currently lived, with the majority of the clinical sample living in institutionalized settings and the majority of the control sample living in independent/supported living settings. This may reflect a tendency to move people once they start to deteriorate which, if correct, is contrary to clinical recommendations that people with AD should be supported to "die in place."

CONCLUSIONS

Further research into the way in which lifestyle factors, particularly living environment, could contribute to the increased risk of AD in adults with DS is required. This may support interventions aimed at preventing or delaying the onset of the disease.

Cognitive resilience in clinical and preclinical Alzheimer's disease: the Association of Amyloid and Tau Burden on cognitive performance

We explored the cross-sectional relationships between β-amyloid (Aβ) and inferior temporal tau deposition (IFT Tau) on cognitive performance and whether cognitive reserve (CR) modifies these associations. We studied 156 participants classified into groups of clinically normal (CN = 133), mild cognitive impairment (MCI = 17) and Alzheimer disease (AD = 6) dementia. AMNART IQ served as a proxy of CR and cognitive performance was assessed using the MMSE. In separate linear regression models predicting MMSE, we examined the interactions of CR x global Aβ and CR x IFT tau across all participants and within the CN group alone. In the whole sample, the interaction between CR and IFT tau was significant (p < 0.003), such that higher CR participants with elevated IFT tau had better MMSE scores compared with low CR participants with similar levels of IFT tau. The interaction between CR and Aβ status did not reach significance (p = 0.093). In CN only, no cross-sectional interactions among CR, Aβ, and IFT tau were observed on MMSE. These findings imply that CR may be protective against early AD processes and enable some individuals to remain cognitively stable despite elevated tau and Aβ burden.

Leisure Activities and Change in Cognitive Stability: A Multivariate Approach

Aging is traditionally associated with cognitive decline, attested by slower reaction times and poorer performance in various cognitive tasks, but also by an increase in intraindividual variability (IIV) in cognitive performance. Results concerning how lifestyle activities protect from cognitive decline are mixed in the literature and all focused on how it affects mean performance. However, IIV has been proven to be an index more sensitive to age differences, and very little is known about the relationships between lifestyle activities and change in IIV in aging. This longitudinal study explores the association between frequency of physical, social, intellectual, artistic, or cultural activities and age-related change in various cognitive abilities, considering both mean performance and IIV. Ninety-six participants, aged 64-93 years, underwent a battery of cognitive tasks at four measurements over a seven-year period, and filled out a lifestyle activity questionnaire. Linear multilevel models were used to analyze the associations between change in cognitive performance and five types of activities. Results showed that the practice of leisure activities was more strongly associated with IIV than with mean performance, both when considering overall level and change in performance. Relationships with IIV were dependent of the cognitive tasks considered and overall results showed protective effects of cultural, physical and intellectual activities on IIV. These results underline the need for considering IIV in the study of age-related cognitive change.

Interaction between personality traits and cerebrospinal fluid biomarkers of Alzheimer's disease pathology modulates cognitive performance

Background

During adulthood, personality characteristics may contribute to the individual capacity to compensate the impact of developing cerebral Alzheimer’s disease (AD) pathology on cognitive impairment in later life. In this study we aimed to investigate whether and how premorbid personality traits interact with cerebrospinal fluid (CSF) markers of AD pathology to predict cognitive performance in subjects with mild cognitive impairment or mild AD dementia and in participants with normal cognition.

Methods

One hundred and ten subjects, of whom 66 were patients with mild cognitive impairment or mild AD dementia and 44 were healthy controls, had a comprehensive medical and neuropsychological examination as well as lumbar puncture to measure CSF biomarkers of AD pathology (amyloid beta_1–42, phosphorylated tau and total-tau). Participants’ proxies completed the Revised NEO Personality Inventory, Form R to retrospectively assess subjects’ premorbid personality.

Results

In hierarchical multivariate regression analyses, including age, gender, education, APOEε4 status and cognitive level, premorbid neuroticism, conscientiousness and agreeableness modulated the effect of CSF biomarkers on cognitive performance. Low premorbid openness independently predicted lower levels of cognitive functioning after controlling for biomarker concentrations.

Conclusion

Our findings suggest that specific premorbid personality traits are associated with cerebral AD pathology and modulate its impact on cognitive performance. Considering personality characteristics may help to appraise a person’s cognitive reserve and the risk of cognitive decline in later life.

Association of cognitive activity and neurocognitive function in blacks and whites with HIV

OBJECTIVE

Older persons with HIV are at risk for impaired cognition, yet there is limited information on modifiable factors associated with neurocognitive function in this group.

DESIGN

This is a cross-sectional observational study of cognitive activities and neurocognitive function.

METHODS

We examined the relation between frequency of cognitive activity and current neurocognitive performance in 176 older persons with HIV [70% African American, 76% men; mean age = 58.7 (SD = 5.5); mean education = 13.2 (SD = 2.8)].

RESULTS

In linear regression models adjusted for demographic variables, we found that higher frequency of cognitive activity was associated with better cognition in global cognition, semantic memory, and perceptual speed. Subsequent models that examined the role of race demonstrated that the association was significant only among Blacks for global cognition, episodic memory, working memory, and perceptual speed (interaction of cognitive activity by race: Estimate range = 0.38-0.55; all P < 0.05).

CONCLUSION

Greater frequency of cognitive activity is associated with better neurocognitive function in older persons with HIV, particularly older Blacks. Longitudinal studies are needed to assess the relation of cognitive activity to change in neurocognitive function in older persons with HIV.

Enhancing Cognitive Functioning in Healthly Older Adults: a Systematic Review of the Clinical Significance of Commercially Available Computerized Cognitive Training in Preventing Cognitive Decline

Successfully assisting older adults to maintain or improve cognitive function, particularly when they are dealing with neurodegenerative disorders such as Alzheimer's disease (AD), remains a major challenge. Cognitive training may stimulate neuroplasticity thereby increasing cognitive and brain reserve. Commercial brain training programs are computerized, readily-available, easy-to-administer and adaptive but often lack supportive data and their clinical validation literature has not been previously reviewed. Therefore, in this review, we report the characteristics of commercially available brain training programs, critically assess the number and quality of studies evaluating the empirical evidence of these programs for promoting brain health in healthy older adults, and discuss underlying causal mechanisms. We searched PubMed, Google Scholar and each program's website for relevant studies reporting the effects of computerized cognitive training on cognitively healthy older adults. The evidence for each program was assessed via the number and quality (PEDro score) of studies, including Randomized Control Trials (RCTs). Programs with clinical studies were subsequently classified as possessing Level I, II or III evidence. Out of 18 identified programs, 7 programs were investigated in 26 studies including follow-ups. Two programs were identified as possessing Level I evidence, three programs demonstrated Level II evidence and an additional two programs demonstrated Level III evidence. Overall, studies showed generally high methodological quality (average PEDro score = 7.05). Although caution must be taken regarding any potential bias due to selective reporting, current evidence supports that at least some commercially available computerized brain training products can assist in promoting healthy brain aging.

Cognitive impairment and mortality among the oldest-old Chinese

OBJECTIVE

This study examined the relationship between cognitive impairment status and all-cause mortality among the oldest-old Chinese.

METHODS

A total of 7474 survey participants 80 years of age and above came from the Chinese Longitudinal Healthy Longevity Survey 1998-2012 waves. Baseline cognitive impairment status was assessed using the Chinese version of the mini-mental state examination (MMSE), with total score ranging from 0 to 30. Cox proportional hazards regressions were performed to examine the relationship between baseline cognitive impairment status in 1998 and subsequent all-cause mortality during 1998-2012, adjusting for various individual characteristics at baseline.

RESULTS

Compared with those with no or mild cognitive impairment (18 ≤ MMSE score ≤ 30) at baseline, participants with moderate-to-severe cognitive impairment (0 ≤ MMSE score ≤ 17) were 28% (95% confidence interval = 20%, 37%) more likely to die during the follow-up period from 1998 to 2012. A dose-response relationship between baseline severity level of cognitive impairment and mortality was evident. Compared with those without cognitive impairment (25 ≤ MMSE score ≤ 30) at baseline, those having mild cognitive impairment (18 ≤ MMSE score ≤ 24), moderate cognitive impairment (10 ≤ MMSE score ≤ 17), and severe cognitive impairment (0 ≤ MMSE score ≤ 9), were 20% (13%, 28%), 38% (27%, 51%), and 47% (33%, 62%) more likely to die during the follow-up period. No statistically significant gender differences in the relationship between cognitive impairment status and mortality were found.

CONCLUSION

Baseline cognitive impairment was inversely associated with longevity among the oldest-old Chinese. Copyright © 2016 John Wiley & Sons, Ltd.

The role of pre-morbid intelligence and cognitive reserve in predicting cognitive efficiency in a sample of Italian elderly

BACKGROUND

Models of cognitive reserve in aging suggest that individual's life experience (education, working activity, and leisure) can exert a neuroprotective effect against cognitive decline and may represent an important contribution to successful aging.

AIM

The objective of the present study is to investigate the role of cognitive reserve, pre-morbid intelligence, age, and education level, in predicting cognitive efficiency in a sample of healthy aged individuals and with probable mild cognitive impairment.

METHODS

Two hundred and eight aging participants recruited from the provincial region of Bari (Apulia, Italy) took part in the study. A battery of standardized tests was administered to them to measure cognitive reserve, pre-morbid intelligence, and cognitive efficiency. Protocols for 10 participants were excluded since they did not meet inclusion criteria, and statistical analyses were conducted on data from the remaining 198 participants. A path analysis was used to test the following model: age, education level, and intelligence directly influence cognitive reserve and cognitive efficiency; cognitive reserve mediates the influence of age, education level, and intelligence on cognitive efficiency.

RESULTS

Cognitive reserve fully mediates the relationship between pre-morbid intelligence and education level and cognitive efficiency, while age maintains a direct effect on cognitive efficiency.

DISCUSSION

Cognitive reserve appears to exert a protective effect regarding cognitive decline in normal and pathological populations, thus masking, at least in the early phases of neurodegeneration, the decline of memory, orientation, attention, language, and reasoning skills.

CONCLUSIONS

The assessment of cognitive reserve may represent a useful evaluation supplement in neuropsychological screening protocols of cognitive decline.

Cognitive leisure activities and future risk of cognitive impairment and dementia: systematic review and meta-analysis

BACKGROUND

As life expectancies continue to rise, modifiable lifestyle factors that may prevent cognitive decline and dementia in later life become increasingly important in order to maintain quality of life in old age.

METHODS

Five meta-analyses were conducted on data from papers identified in a systematic review. Studies were grouped according to outcomes (dementia, cognitive impairment including amnestic Mild Cognitive Impairment (aMCI), Mild Cognitive Impairment (MCI), and cognitive decline) and output (risk (RR), odds (OR), or hazard ratios (HR)).

RESULTS

Nineteen studies met our inclusion criteria and quality assessments. Four of five meta-analyses showed significant associations between participation in cognitive leisure activities and reduced risk of cognitive impairment (OR = 0.69, 95% CI: 0.56-0.85) and dementia (HR = 0.58, 95% CI: 0.46-0.74; RR = 0.61, 95% CI: 0.42-0.90; OR = 0.78, 95% CI: 0.67-0.90). However, one pooled analysis of cognitive impairment studies did not reach significance (HR = 0.85, 95% CI: 0.71-1.02). Mentally stimulating leisure activities were significantly associated with later life cognition (β = 0.11, p = 0.05), better memory (β = 0.20, 95% CI: 0.11-0.29), speed of processing (β = 0.37, 95% CI: 0.29-0.45), and executive functioning (β = 0.23, 95% CI: 0.15-0.29), and less decline in overall cognition (β = -0.23, p < 0.01), language (β = -0.11, p < 0.05), and executive functioning (β = -0.13, p < 0.05). Activities were also shown to reduce rate of cognitive decline (estimate = 0.03, SE = 0.01, p = 0.00).

CONCLUSIONS

There is increasing evidence that participation in cognitively stimulating leisure activities may contribute to a reduction of risk of dementia and cognitive impairment in later life. Promoting involvement in such activities across lifespan could be an important focus for primary prevention strategies for governments and health services.

The Synapse Project: Engagement in mentally challenging activities enhances neural efficiency

PURPOSE

Correlational and limited experimental evidence suggests that an engaged lifestyle is associated with the maintenance of cognitive vitality in old age. However, the mechanisms underlying these engagement effects are poorly understood. We hypothesized that mental effort underlies engagement effects and used fMRI to examine the impact of high-challenge activities (digital photography and quilting) compared with low-challenge activities (socializing or performing low-challenge cognitive tasks) on neural function at pretest, posttest, and one year after the engagement program.

METHODS

In the scanner, participants performed a semantic-classification task with two levels of difficulty to assess the modulation of brain activity in response to task demands.

RESULTS

The High-Challenge group, but not the Low-Challenge group, showed increased modulation of brain activity in medial frontal, lateral temporal, and parietal cortex-regions associated with attention and semantic processing-some of which were maintained a year later. This increased modulation stemmed from decreases in brain activity during the easy condition for the High-Challenge group and was associated with time committed to the program, age, and cognition.

CONCLUSIONS

Sustained engagement in cognitively demanding activities facilitated cognition by increasing neural efficiency. Mentally-challenging activities may be neuroprotective and an important element to maintaining a healthy brain into late adulthood.

Relations between Recent Past Leisure Activities with Risks of Dementia and Cognitive Functions after Stroke

Background

Leisure activity participation has been shown to lower risks of cognitive decline in non-stroke populations. However, effects of leisure activities participation upon cognitive functions and risk of dementia after stroke are unclear. The purpose of this study is to examine the effects of recent past leisure activities participation upon cognitive functions and risk of incident dementia after stroke.

Methods

Hospital-based, retrospective cohort study. 88 of 1,013 patients with stroke or TIA having no prestroke dementia were diagnosed to have incident poststroke dementia (PSD) 3–6 months after stroke. Regular participation (≥3 times per week) in intellectual, recreational, social and physical activities over the year before the index stroke was retrospectively recorded at 3–6 months after stroke.

Results

Logistic regression analyses showed that regular participation in intellectual (RR 0.36, 95%CI 0.20–0.63) and stretching & toning physical exercise (0.37, 0.21–0.64) was significantly associated with a reduced risk of PSD after controlling for age, education, prestroke cognitive decline, stroke subtype, prior strokes and chronic brain changes including white matter changes, old infarcts and global atrophy. Results were similar in patients with past strokes in unadjusted models. Participation in increased number of activities in general (r = 0.41, p<0.01) and in intellectual (r = 0.40, p<0.01), recreational (r = 0.24, p<0.01), strenuous aerobic (r = 0.23, p<0.01) and mind-body (r = 0.10, p<0.01) activities was associated with higher poststroke Mini-mental State Examination scores in models adjusted for prestroke cognitive decline.

Conclusions

Regular participation in intellectual activities and stretching & toning exercise was associated with a significantly reduced short-term risk of PSD in patients with and without recurrent strokes. Participation in greater number of recent past leisure activities was associated with better poststroke cognitive performance. Findings of this retrospective cohort study call for studies of activity intervention for prevention of cognitive decline in individuals at elevated risk of stroke.

The Busier the Better: Greater Busyness Is Associated with Better Cognition

Sustained engagement in mentally challenging activities has been shown to improve memory in older adults. We hypothesized that a busy schedule would be a proxy for an engaged lifestyle and would facilitate cognition. Here, we examined the relationship between busyness and cognition in adults aged 50-89. Participants (N = 330) from the Dallas Lifespan Brain Study (DLBS) completed a cognitive battery and the Martin and Park Environmental Demands Questionnaire (MPED), an assessment of busyness. Results revealed that greater busyness was associated with better processing speed, working memory, episodic memory, reasoning, and crystallized knowledge. Hierarchical regressions also showed that, after controlling for age and education, busyness accounted for significant additional variance in all cognitive constructs-especially episodic memory. Finally, an interaction between age and busyness was not present while predicting cognitive performance, suggesting that busyness was similarly beneficial in adults aged 50-89. Although correlational, these data demonstrate that living a busy lifestyle is associated with better cognition.

Cognitive Reserve and the Prevention of Dementia: the Role of Physical and Cognitive Activities

PURPOSE OF REVIEW

The article discusses the two most significant modifiable risk factors for dementia, namely, physical inactivity and lack of stimulating cognitive activity, and their effects on developing cognitive reserve.

RECENT FINDINGS

Both of these leisure-time activities were associated with significant reductions in the risk of dementia in longitudinal studies. In addition, physical activity, particularly aerobic exercise, is associated with less age-related gray and white matter loss and with less neurotoxic factors. On the other hand, cognitive training studies suggest that training for executive functions (e.g., working memory) improves prefrontal network efficiency, which provides support to brain functioning in the face of cognitive decline. While physical activity preserves neuronal structural integrity and brain volume (hardware), cognitive activity strengthens the functioning and plasticity of neural circuits (software), thus supporting cognitive reserve in different ways. Future research should examine whether lifestyle interventions incorporating these two domains can reduce incident dementia.

Independent and combined effects of cognitive and physical activity on incident MCI

INTRODUCTION

The objective of this study was to examine the independent and combined influences of late-life cognitive activity (CA) and physical activity (PA) on the risk of incident mild cognitive impairment (MCI).

METHODS

We used interval censored survival modeling to examine the risk of incident MCI (Clinical Dementia Rating [CDR] = 0.5) as a function of CA (high vs. low) and at least moderate intensity PA (any vs. none) among 864 cognitively normal (CDR = 0) older adults.

RESULTS

During three annual follow-up waves, 72 participants developed MCI. Compared with low CA with no PA, significant reductions in risk for MCI were observed for high CA with any PA (hazards ratio (HR) = 0.20, 95% confidence interval (CI) 0.07-0.52) and low CA with any PA (HR = 0.52, 95% CI 0.29-0.93), but not for high CA without PA (HR = 0.94, 95% CI 0.45-1.95).

DISCUSSION

These findings suggest that a combination of CA and PA may be most efficacious at reducing the risk for cognitive impairment.

Bridging the Translation Gap: From Dementia Risk Assessment to Advice on Risk Reduction

Dementia risk reduction is a global health and fiscal priority given the current lack of effective treatments and the projected increased number of dementia cases due to population ageing. There are often gaps among academic research, clinical practice, and public policy. We present information on the evidence for dementia risk reduction and evaluate the progress required to formulate this evidence into clinical practice guidelines. This narrative review provides capsule summaries of current evidence for 25 risk and protective factors associated with AD and dementia according to domains including biomarkers, demographic, lifestyle, medical, and environment. We identify the factors for which evidence is strong and thereby especially useful for risk assessment with the goal of personalising recommendations for risk reduction. We also note gaps in knowledge, and discuss how the field may progress towards clinical practice guidelines for dementia risk reduction.

The Epidemiological Scale of Alzheimer's Disease

Alzheimer's disease (AD) has increased from a few cases in a country at the beginning of the 20th century to an incidence of recording a case every 7 seconds in the world. From a rare disease it has reached the top 8 of major health problems in the world. One of the epidemiological problems of AD is the fact that authors from different countries use different reporting units. Some report numbers to 100,000 inhabitants, others to 1,000 inhabitants and others report the total number of cases in a country. Standardization of these reports is strictly necessary. The rise in incidence and prevalence with age is known, but interesting to see is that the incidence and prevalence do not rise in a parallel manner with age as simple logic would assume. Between the ages of 60 and 90, the incidence in men increases two times and in women 41 times, prevalence increase in men is 55.25-fold and in women 77-fold. Regarding the women/men ratio, the incidence is 20.5-fold increased, and prevalence is merely 1.3936-fold increased. These numbers raise concerns about the evolution of the disease. Regarding mild cognitive impairment (MCI)/AD ratio, only about 1 in 2 people get AD (raising?) issues about the pathogenic disease relatedness.

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.

Exercise, sedentary pastimes, and cognitive performance in healthy older adults

BACKGROUND

Moderately vigorous physical activity (MVPA) provides a protective affect against cognitive decline and cardiovascular risk factors. Less is known about sedentary pastimes or non exercise physical activity (NEPA) and cognitive performance.

METHOD

125 healthy adults 65 or older with no clinical evidence of cognitive impairment were enrolled. The CogState computerized neurocognitive battery was administered. Leisure activities were measured using the Community Health Activity Program for Seniors (CHAMPS).

RESULTS

Sedentary pastimes were associated with executive dysfunction (P = 0.01); MVPA with high memory scores (P = 0.05) and NEPA with improved working memory (P = 0.05). Only sedentary pastimes and executive dysfunction retained significance after correction for multiple comparisons. Smoking and alcohol confounded the association of memory with sedentary pastimes and MVPA.

CONCLUSIONS

Study highlights: negative impact of sedentary pastimes on executive function, need for additional investigation of sedentary behavior, NEPA, the impact of addictions upon activity in late life.

Retirement age and the age of onset of Alzheimer's disease: results from the ICTUS study

Objectives

To test whether deferred retirement is associated with delayed onset of Alzheimer’s disease (AD), and, if so, to determine whether retirement age still predicts the age at onset of AD when two potential biases are considered.

Methods

The study sample was gathered from the Impact of Cholinergic Treatment Use/Data Sharing Alzheimer cohort (ICTUS/DSA), a European study of 1,380 AD patients. Information regarding retirement age, onset of symptoms and covariates was collected at baseline whereas age at diagnosis was gathered from the patient’s medical record prior to study entry. Linear mixed models, adjusted for gender, education, occupation, center, country, household income, depression and cardiovascular risk factors were conducted on 815 patients.

Results

(1) The global analyses (n = 815) revealed that later age at retirement was associated with later age at diagnosis (β = 0.31, p < 0.0001); (2) once the selection bias was considered (n = 637), results showed that this association was weaker but remained significant (β = 0.15, p = 0.004); (3) once the bias of the reverse causality (i.e., the possibility that subjects may have left the workforce due to prior cognitive impairment) was considered (n = 447), the effect was no longer significant (β = 0.06, p = 0.18).

Conclusion

The present study supports that there is an association between retirement age and age at onset of AD. However, the strength of this association appears to be overestimated due to the selection bias. Moreover, the causality issue remains unresolved. Further prospective investigations are mandatory in order to correctly address this question.

Epigenomics of Alzheimer's disease

Alzheimer's disease (AD) is a large and growing public health problem. It is characterized by the accumulation of amyloid β peptides and abnormally phosphorylated tau proteins that are associated with cognitive decline and dementia. Much has been learned about the genomics of AD from linkage analyses and, more recently, genome-wide association studies. Several but not all aspects of the genomic landscape are involved in amyloid β metabolism. The moderate concordance of disease among twins suggests other factors, potentially epigenomic factors, are related to AD. We are at the earliest stages of examining the relation of the epigenome to the clinical and pathologic phenotypes that characterize AD. Our literature review suggests that there is some evidence of age-related changes in human brain methylation. Unfortunately, studies of AD have been relatively small with limited coverage of methylation sites and microRNA, let alone other epigenomic marks. We are in the midst of 2 large studies of human brains including coverage of more than 420,000 autosomal cytosine-guanine dinucleotides with the Illumina Infinium HumanMethylation450 BeadArray, and histone acetylation with chromatin immunoprecipitation sequencing. We present descriptive data to help inform other researchers what to expect from these approaches to better design and power their studies. We then discuss future directions to inform on the epigenomic architecture of AD.

Associations between Dementia Outcomes and Depressive Symptoms, Leisure Activities, and Social Support

Background

Social relations and depressive symptoms are intertwined. They both predict subsequent dementia, but only few studies on the association between social life aspects and subsequent dementia exist.

Methods

The risk of subsequent dementia was estimated over 2 follow-up assessments, each 18 months apart, depending on leisure activity, social support (general scale and the 3 factors emotional support, practical support, and social integration), and depressive symptoms, using proportional hazard models in a cohort of elderly patients (n = 2,300, with a mean age of 82.45 years) recruited for the study by their general practitioners.

Results

Higher depressive symptoms and lower cognitive and physical activity were associated with an increased risk of subsequent all-cause dementia and Alzheimer's dementia (AD). While neither social engagement nor the general social support scale was associated with subsequent dementia, a higher level of social integration was associated with a lower dementia risk. In combined models, the results for activity variables remained similar, but the strength of the association between depressive symptoms and the subsequent risk of dementia decreased, and the association with social integration disappeared.

Conclusions

Depressive symptoms increased and activity variables decreased the risk of subsequent dementia; however, activity variables, namely cognitive and physical activity, partly mediated the effect of depressive symptoms on the subsequent risk of all-cause dementia and AD. In many cases, social support was not associated with a risk of subsequent dementia.

Can Clinical Data Predict Progression to Dementia in Amnestic Mild Cognitive Impairment?

Background:

To determine whether clinical data obtained by history and physical examination can predict eventual progression to dementia in a cohort of elderly people with mild cognitive impairment.

Methods:

A prospective, longitudinal study of a cohort of elderly subjects with amnestic Mild Cognitive Impairment (MCI). Ninety subjects meeting the criteria for amnestic MCI were recruited and followed annually for an average of 3.3 years. Main outcome measure was the development of dementia determined by clinical assessment with confirmatory neuropsychological evaluation.

Results:

Fifty patients (56%) developed dementia on follow-up. They were older, had lower Mini-mental status exam (MMSE) scores and a shorter duration of symptoms at the time of first assessment. Multivariate logistic regression analysis identified age at symptom onset as the only clinical parameter which distinguished the group that deteriorated to dementia from the group that did not. The odds ratio for age was 1.1 (confidence interval 1.04 - 1.18).

Conclusions:

Patients presenting with amnestic MCI insufficient for the diagnosis of dementia are at high risk of developing dementia on follow-up. In our cohort, 56% were diagnosed with dementia over an average period of 5.9 years from symptom onset. The only clinical predictor for the eventual development of dementia was older age at symptom onset. Clinical features alone were insufficient to predict development of dementia.

A combination of physical activity and computerized brain training improves verbal memory and increases cerebral glucose metabolism in the elderly

Physical exercise interventions and cognitive training programs have individually been reported to improve cognition in the healthy elderly population; however, the clinical significance of using a combined approach is currently lacking. This study evaluated whether physical activity (PA), computerized cognitive training and/or a combination of both could improve cognition. In this nonrandomized study, 224 healthy community-dwelling older adults (60-85 years) were assigned to 16 weeks home-based PA (n=64), computerized cognitive stimulation (n=62), a combination of both (combined, n=51) or a control group (n=47). Cognition was assessed using the Rey Auditory Verbal Learning Test, Controlled Oral Word Association Test and the CogState computerized battery at baseline, 8 and 16 weeks post intervention. Physical fitness assessments were performed at all time points. A subset (total n=45) of participants underwent [(18)F] fluorodeoxyglucose positron emission tomography scans at 16 weeks (post-intervention). One hundred and ninety-one participants completed the study and the data of 172 participants were included in the final analysis. Compared with the control group, the combined group showed improved verbal episodic memory and significantly higher brain glucose metabolism in the left sensorimotor cortex after controlling for age, sex, premorbid IQ, apolipoprotein E (APOE) status and history of head injury. The higher cerebral glucose metabolism in this brain region was positively associated with improved verbal memory seen in the combined group only. Our study provides evidence that a specific combination of physical and mental exercises for 16 weeks can improve cognition and increase cerebral glucose metabolism in cognitively intact healthy older adults.

Antecedents of intact cognition and dementia at age 90 years: a prospective study

OBJECTIVES

This study aimed to examine the possible antecedents of both dementia and sustained intact cognition at age 90 years among men who underwent a prospective, multidisciplinary assessment from ages 19 to 90 years, with little attrition.

METHODS

We conducted a prospective 20-year reassessment of 196 (out of 268) former Harvard college sophomores who survived until age 70 years. Since 1939, the study gathered measurements of childhood environment, dominant personality traits, objective mental and physical health over time, smoking in pack-years, alcohol abuse, and depression. Questionnaires were obtained every 2 years and physical exams every 5 years. Cognitive status was assessed at ages 80, 85, and 90 years.

RESULTS

Despite addressing a wide variety of health, behavioral, and social factors over the lifespan, we observed few predictors with strong association with either intact cognition at age 90 years (n = 40) or dementia (n = 44). Univariate analysis revealed seven suggestive predictors of intact cognition at age 90 years or of dementia: warm childhood relationship with mother, exercise at age 60 years, high maternal education, young age of mother at subject's birth, low body mass index, good physical health at 60 years, and late retirement. Only the first three variables, warm childhood relationship with mother, exercise at age 60 years, and high maternal education, remained significant with logistic regression.

CONCLUSIONS

In this prospective study of long-lived, highly educated men, several well-known putative predictors of Alzheimer's disease did not distinguish those who over the next 20 years developed dementia from those with unimpaired cognition until age 90 years.

Early life instruction in foreign language and music and incidence of mild cognitive impairment

OBJECTIVE

To test the hypothesis that foreign language and music instruction in early life are associated with lower incidence of mild cognitive impairment (MCI) and slower rate of cognitive decline in old age.

METHOD

At enrollment in a longitudinal cohort study, 964 older persons without cognitive impairment estimated years of foreign language and music instruction by age 18. Annually thereafter they completed clinical evaluations that included cognitive testing and clinical classification of MCI.

RESULTS

There were 264 persons with no foreign language instruction, 576 with 1-4 years, and 124 with > 4 years; 346 persons with no music instruction, 360 with 1-4 years, and 258 with > 4 years. During a mean of 5.8 years of observation, 396 participants (41.1%) developed MCI. In a proportional hazards model adjusted for age, sex, and education, higher levels (> 4 years) of foreign language (hazard ratio [HR] = 0.687, 95% confidence interval [CI] [0.482, 0.961]) and music (HR = 0.708, 95% CI [0.539, 0.930]) instruction by the age of 18 were each associated with reduced risk of MCI. The association persisted after adjustment for other early life indicators of an enriched cognitive environment, and it was stronger for nonamnestic than amnestic MCI. Both foreign language and music instruction were associated with higher initial level of cognitive function, but neither instruction measure was associated with cognitive decline.

CONCLUSIONS

Higher levels of foreign language and music instruction during childhood and adolescence are associated in old age with lower risk of developing MCI but not with rate of cognitive decline.

Training Older Adults to Use Tablet Computers: Does It Enhance Cognitive Function?

Purpose of the Study:

Recent evidence shows that engaging in learning new skills improves episodic memory in older adults. In this study, older adults who were computer novices were trained to use a tablet computer and associated software applications. We hypothesize that sustained engagement in this mentally challenging training would yield a dual benefit of improved cognition and enhancement of everyday function by introducing useful skills.

Design and Methods:

A total of 54 older adults (age 60-90) committed 15 hr/week for 3 months. Eighteen participants received extensive iPad training, learning a broad range of practical applications. The iPad group was compared with 2 separate controls: a Placebo group that engaged in passive tasks requiring little new learning; and a Social group that had regular social interaction, but no active skill acquisition. All participants completed the same cognitive battery pre- and post-engagement.

Results:

Compared with both controls, the iPad group showed greater improvements in episodic memory and processing speed but did not differ in mental control or visuospatial processing.

Implications:

iPad training improved cognition relative to engaging in social or nonchallenging activities. Mastering relevant technological devices have the added advantage of providing older adults with technological skills useful in facilitating everyday activities (e.g., banking). This work informs the selection of targeted activities for future interventions and community programs.

Resilient brain aging: characterization of discordance between Alzheimer's disease pathology and cognition

BACKGROUND

Although it is now evident that normal cognition can occur despite significant AD pathology, few studies have attempted to characterize this discordance, or examine factors that may contribute to resilient brain aging in the setting of AD pathology.

METHODS

More than 2,000 older persons underwent annual evaluation as part of participation in the Religious Orders Study or Rush Memory Aging Project. A total of 966 subjects who had brain autopsy and comprehensive cognitive testing proximate to death were analyzed. Resilience was quantified as a continuous measure using linear regression modeling, where global cognition was entered as a dependent variable and global pathology was an independent variable. Studentized residuals generated from the model represented the discordance between cognition and pathology, and served as measure of resilience. The relation of resilience index to known risk factors for AD and related variables was examined.

RESULTS

Multivariate regression models that adjusted for demographic variables revealed significant associations for early life socioeconomic status, reading ability, APOE-ε4 status, and past cognitive activity. A stepwise regression model retained reading level (estimate = 0.10, SE = 0.02; p< 0.0001) and past cognitive activity (estimate = 0.27, SE = 0.09; p = 0.002), suggesting the potential mediating role of these variables for resilience.

CONCLUSIONS

The construct of resilient brain aging can provide a framework for quantifying the discordance between cognition and pathology, and help identify factors that may mediate this relationship.

A complex multimodal activity intervention to reduce the risk of dementia in mild cognitive impairment--ThinkingFit: pilot and feasibility study for a randomized controlled trial

BACKGROUND

Dementia affects 35 million people worldwide and is currently incurable. Many cases may be preventable because regular participation in physical, mental and social leisure activities during middle age is associated with up to 47% dementia risk reduction. However, the majority of middle-aged adults are not active enough. MCI is therefore a clear target for activity interventions aimed at reducing dementia risk. An active lifestyle during middle age reduces dementia risk but it remains to be determined if increased activity reduces dementia risk when MCI is already evident. Before this can be investigated conclusively, complex multimodal activity programmes are required that (1) combine multiple health promoting activities, (2) engage people with MCI, and (3) result in sufficient adherence rates.

METHODS

We designed the ThinkingFit programme to engage people with MCI in a complex intervention comprised of three activity components: physical activity, group-based cognitive stimulation (GCST) and individual cognitive stimulation (ICST). Engagement and adherence was promoted by applying specific psychological techniques to enhance behavioural flexibility in an early pre-phase and during the course of the intervention. To pilot the intervention, participants served as their own controls during a 6- to 12-week run-in period, which was followed by 12 weeks of activity intervention.

RESULTS

Out of 212 MCI patients screened, 163 were eligible, 70 consented and 67 completed the intervention (mean age 74 years). Activity adherence rates were high: physical activity = 71%; GCST = 83%; ICST = 67%. Significant treatment effects (p < .05) were evident on physical health outcomes (decreased BMI and systolic blood pressure, [pre/post values of 26.3/25.9 kg/m2 and 145/136 mmHg respectively]), fitness (decreased resting and recovery heart rate [68/65 bpm and 75/69 bpm]), and cognition (improved working memory [5.3/6.3 items]).

CONCLUSIONS

We found satisfactory recruitment, retention and engagement rates, coupled with significant treatment effects in elderly MCI patients. It appears feasible to conduct randomized controlled trials of the dementia prevention potential of complex multimodal activity programmes like ThinkingFit.

TRIAL REGISTRATION

ClinicalTrials.gov registration nr: NCT01603862; date: 17/5/2012.

The impact of cognitive training and mental stimulation on cognitive and everyday functioning of healthy older adults: a systematic review and meta-analysis

This systematic review and meta-analysis investigates the impact of cognitive training and general mental stimulation on the cognitive and everyday functioning of older adults without known cognitive impairment. We examine transfer and maintenance of intervention effects, and the impact of training in group versus individual settings. Thirty-one randomised controlled trials were included, with 1806 participants in cognitive training groups and 386 in general mental stimulation groups. Meta-analysis results revealed that compared to active controls, cognitive training improved performance on measures of executive function (working memory, p=0.04; processing speed, p<0.0001) and composite measures of cognitive function (p=0.001). Compared to no intervention, cognitive training improved performance on measures of memory (face-name recall, p=0.02; immediate recall, p=0.02; paired associates, p=0.001) and subjective cognitive function (p=0.01). The impact of cognitive training on everyday functioning is largely under investigated. More research is required to determine if general mental stimulation can benefit cognitive and everyday functioning. Transfer and maintenance of intervention effects are most commonly reported when training is adaptive, with at least ten intervention sessions and a long-term follow-up. Memory and subjective cognitive performance might be improved by training in group versus individual settings.

Requirements of older adults for a daily use of an internet-based cognitive training platform

A decline of cognitive abilities is a part of normal human ageing. However, recent research has demonstrated that an enriched environment can have a beneficial impact on cognitive function in old age. Accordingly, mentally and socially active lifestyles are associated with less cognitive decline in old age. Specific interventions such as computerized cognitive training programs for older adults are also known to have a positive effect on the level of cognitive functioning. Therefore, online platforms combining cognitive training with web 2.0 features may yield multiple benefits for older users. However, to date only little research exists on technological acceptance and media use in this age-group especially for cognitively-impaired seniors. Therefore, in order to assess specific preferences and potential barriers of older adults regarding a web-based platform for cognitive training, we conducted qualitative interviews with 12 older adults. Half of the participants were diagnosed with mild cognitive impairment (MCI). Most importantly, our results show that cognitive exercises should incorporate themes and topics older adults are interested in. Additional communication features could serve as ideal methods for increasing user motivation. Furthermore, we derived eight critical requirements of older adults concerning daily use of a web-based cognitive training platform. Implications for future research and development are discussed.

Cognitive status moderates the relationship between out-of-home behavior (OOHB), environmental mastery and affect

Studies on the relationship between behavioral competence, such as the competence of exerting out-of-home behavior (OOHB), and well-being in older adults have rarely addressed cognitive status as a potentially moderating factor. We included 35 persons with early-stage dementia of the Alzheimer's type (DAT), 76 individuals with mild cognitive impairment (MCI) and 146 cognitively healthy (CH) study participants (grand mean age: M=72.9 years; SD=6.4 years). OOHB indicators were assessed based on a multi-method assessment strategy, using both GPS (global positioning system) tracking technology and structured self-reports. Environmental mastery and positive as well as negative affect served as well-being indicators and were assessed by established questionnaires. Three theoretically postulated OOHB dimensions of different complexity (out-of-home walking behavior, global out-of-home mobility, and out-of-home activities) were supported by confirmatory factor analysis (CFA). We also found in the DAT group that environmental mastery was substantially and positively related to less complex out-of-home walking behavior, which was not the case in MCI and CH individuals. In contrast, more complex out-of-home activities were associated with higher negative affect in the DAT as well as the MCI group, but not in CH persons. These findings point to the possibility that relationships between OOHB and well-being depend on the congruence between available cognitive resources and the complexity of the OOHB dimension considered.

Measurable benefits on brain activity from the practice of educational leisure

Even if behavioral studies relate leisure practices to the preservation of memory in old persons, there is unsubstantial evidence of the import of leisure on brain activity.

Aim: This study was to compare the brain activity of elderly retired people who engage in different types of leisure activities.

Methods: Quasi-experimental study over a sample of 60 elderly, retired subjects distributed into three groups according to the leisure activities they practised: educational leisure (G1), memory games (G2), and card games (G3). Applied measures include the conceptual distinction between free time and leisure, the test of the organization of free time measuring 24 clock divisions, and EEG register during 12 word list memorizing.

Results: The results show that the type of leisure activity is associated with significant quantitative differences regarding the use of free time. G1 devotes more time to leisure activities than G2 (p = 0.007) and G3 (p = 0.034). G1 rests more actively than the other two groups (p = 0.001). The electrical localization of brain activity indicated a reverse tendency of activation according to the bands and groups.

Discussion: Engaging in educational leisure activities is a useful practice to protect healthy brain compensation strategies. Future longitudinal research may verify the causal relation between practicing educational leisure activities and functional brain aging.

Advances in the prevention of Alzheimer's disease and dementia

BACKGROUND

Definitions and diagnostic criteria for all medical conditions are regularly subjected to reviews and revisions as knowledge advances. In the field of Alzheimer's disease (AD) research, it has taken almost three decades for diagnostic nomenclature to undergo major re-examination. The shift towards presymptomatic and pre-dementia stages of AD has brought prevention and treatment trials much closer to each other than before.

METHODS

Here we discuss: (i) the impact of diagnostic reliability on the possibilities for developing preventive strategies for AD; (ii) the scientific evidence to support moving from observation to action; (iii) ongoing intervention studies; and (iv) the methodological issues and prospects for balancing strategies for high-risk individuals with those for broad population-based prevention.

RESULTS

The associations between neuropathology and cognition are still not entirely clear. In addition, the risk factors for AD dementia and the neuropathological hallmarks of AD may not necessarily be the same. Cognitive impairment has a clearer clinical significance and should therefore remain the main focus of prevention. Risk/protective factors for dementia/AD need to be studied from a life-course perspective. New approaches in prevention trials include enrichment strategies based on genetic risk factors or beta-amyloid biomarkers (at least four ongoing pharmacological trials), and multidomain interventions simultaneously targeting various vascular and lifestyle-related risk factors (at least three ongoing trials). Experience from prevention programmes in other chronic diseases can provide additional methodological improvements.

CONCLUSIONS

Building infrastructures for international collaborations is necessary for managing the worldwide public health problem of AD and dementia. The International Database on Aging and Dementia (IDAD) and the European Dementia Prevention Initiative (EDPI) are examples of ongoing international efforts aiming to improve the methodology of preventive studies and provide the basis for larger intervention trials.

Associations between white matter microstructure and amyloid burden in preclinical Alzheimer's disease: A multimodal imaging investigation

Some cognitively healthy individuals develop brain amyloid accumulation, suggestive of incipient Alzheimer's disease (AD), but the effect of amyloid on other potentially informative imaging modalities, such as Diffusion Tensor Imaging (DTI), in characterizing brain changes in preclinical AD requires further exploration. In this study, a sample (N = 139, mean age 60.6, range 46 to 71) from the Wisconsin Registry for Alzheimer's Prevention (WRAP), a cohort enriched for AD risk factors, was recruited for a multimodal imaging investigation that included DTI and [C-11]Pittsburgh Compound B (PiB) positron emission tomography (PET). Participants were grouped as amyloid positive (Aβ+), amyloid indeterminate (Aβi), or amyloid negative (Aβ-) based on the amount and pattern of amyloid deposition. Regional voxel-wise analyses of four DTI metrics, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), and radial diffusivity (Dr), were performed based on amyloid grouping. Three regions of interest (ROIs), the cingulum adjacent to the corpus callosum, hippocampal cingulum, and lateral fornix, were selected based on their involvement in the early stages of AD. Voxel-wise analysis revealed higher FA among Aβ+ compared to Aβ- in all three ROIs and in Aβi compared to Aβ- in the cingulum adjacent to the corpus callosum. Follow-up exploratory whole-brain analyses were consistent with the ROI findings, revealing multiple regions where higher FA was associated with greater amyloid. Lower fronto-lateral gray matter MD was associated with higher amyloid burden. Further investigation showed a negative correlation between MD and PiB signal, suggesting that Aβ accumulation impairs diffusion. Interestingly, these findings in a largely presymptomatic sample are in contradistinction to relationships reported in the literature in symptomatic disease stages of Mild Cognitive Impairment and AD, which usually show higher MD and lower FA. Together with analyses showing that cognitive function in these participants is not associated with any of the four DTI metrics, the present results suggest an early relationship between PiB and DTI, which may be a meaningful indicator of the initiating or compensatory mechanisms of AD prior to cognitive decline.

Future directions in Alzheimer's disease from risk factors to prevention

The increase in life expectancy has resulted in a high occurrence of dementia and Alzheimer's disease (AD). Research on AD has undergone a paradigm shift from viewing it as a disease of old age to taking a life course perspective. Several vascular, lifestyle, psychological and genetic risk factors influencing this latent period have been recognized and they may act both independently and by potentiating each other. These risk factors have consequently been used to derive risk scores for predicting the likelihood of dementia. Despite population differences, age, low education and vascular risk factors were identified as key factors in all scoring systems. Risk scores can help to identify high-risk individuals who might benefit from different interventions. The European Dementia Prevention Initiative (EDPI), an international collaboration, encourages data sharing between different randomized controlled trials. At the moment, it includes three large ongoing European trials: Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER), Prevention of Dementia by Intensive Vascular Care (preDIVA), and Multidomain Alzheimer Prevention study (MAPT). Recently EDPI has developed a "Healthy Aging through Internet Counseling in Elderly" (HATICE) program, which intends to manage modifiable risk factors in an aged population through an easily accessible Internet platform. Thus, the focus of dementia research has shifted from identification of potential risk factors to using this information for developing interventions to prevent or delay the onset of dementia as well as identifying special high-risk populations who could be targeted in intervention trials.

The Impact of Exercise, Cognitive Activities, and Socialization on Cognitive Function: Results From the National Long-Term Care Survey

Currently, there are no effective treatments for Alzheimer's disease and related disorders and age continues to be a robust risk factor. Thus, population aging in the United States may have catastrophic results if interventions are not found and implemented. This study examines possible associations between cognitive impairment and exercise, cognitive activities, and socialization. Cognitive activities, socialization, and exercise were assessed at baseline, and cognitive function was measured at baseline, 5-year, and 10-year follow-up. Controlling for baseline cognitive function, age, sex, education, diabetes, and hypertension, linear regression was performed. Engagement in cognitive activities was inversely associated with the onset of cognitive impairment at 5-year follow-up but was no longer significant at 10-year follow-up. Exercise was associated with a lower risk of cognitive impairment at 10-year follow-up but was not significant at 5-year follow-up. Associations with socialization were not statistically significant at either follow-up.

Cognitive Consequences of Aging with HIV: Implications for Neuroplasticity and Rehabilitation

Combination active antiretroviral therapy prevents HIV from replicating and ravaging the immune system, thus allowing people to age with this disease. Unfortunately, the synergistic effects of HIV and aging can predispose many to become more at-risk of developing cognitive deficits which can interfere with medical management, everyday functioning, and quality of life. The purpose of this article is to describe the role of cognitive reserve and neuroplasticity on cognitive functioning in those aging with this disease. Specifically, the role of environment and the health of these individuals can compromise cognitive functioning. Fortunately, some cognitive interventions such as prevention and management of co-morbidities, cognitive remediation therapy, and neurotropic medications may be of value in preventing and rehabilitating the cognitive consequences of aging with HIV. Novel approaches such as cognitive prescriptions, transcranial direct stimulation, and binaural beat therapy may also be considered as possible techniques for cognitive rehabilitation.