Cognitive activity and the cognitive morbidity of Alzheimer disease

Mapping the impact of age and APOE risk factors for late onset Alzheimer's disease on long range brain connections through multiscale bundle analysis

Alzheimer's disease currently has no cure and is usually detected too late for interventions to be effective. In this study we have focused on cognitively normal subjects to study the impact of risk factors on their long-range brain connections. To detect vulnerable connections, we devised a multiscale, hierarchical method for spatial clustering of the whole brain tractogram and examined the impact of age and APOE allelic variation on cognitive abilities and bundle properties including texture e.g., mean fractional anisotropy, variability, and geometric properties including streamline length, volume, and shape, as well as asymmetry. We found that the third level subdivision in the bundle hierarchy provided the most sensitive ability to detect age and genotype differences associated with risk factors. Our results indicate that frontal bundles were a major age predictor, while the occipital cortex and cerebellar connections were important risk predictors that were heavily genotype dependent, and showed accelerated decline in fractional anisotropy, shape similarity, and increased asymmetry. Cognitive metrics related to olfactory memory were mapped to bundles, providing possible early markers of neurodegeneration. In addition, physiological metrics such as diastolic blood pressure were associated with changes in white matter tracts. Our novel method for a data driven analysis of sensitive changes in tractography may differentiate populations at risk for AD and isolate specific vulnerable networks.

Changes in Body Mass Index and Incident Mild Cognitive Impairment Among African American Older Adults

BACKGROUND

Previous research suggests a decline in body mass index (BMI) among older adults is associated with negative health outcomes, including mild cognitive impairment (MCI) and incident dementia. However, no studies have examined the effects of education or developing MCI on BMI trajectories over time. The purpose of this investigation was to characterize trajectories of change in BMI among older adults who develop MCI.

METHODS

Participants were from the Minority Aging Research Study (MARS), a longitudinal cohort study of cognitive decline and Alzheimer's disease in older African Americans living in the greater Chicago, Illinois, area. The study included annual clinical evaluations of cognitive status, as well as measurements of height and weight for BMI calculation. Older African American participants without cognitive impairment at baseline were included in the present analysis (N = 436, 78% women, mean baseline age = 72 [SD = 5.7], mean education = 15 [SD = 3.5]).

RESULTS

In piecewise linear mixed-effects models that included a random intercept and 2 random slopes, BMI declined over time (B = -0.20, SE = 0.02, p < .001), with a faster decline after MCI diagnosis (additional decline, B = -0.15, SE = 0.06, p = .019). Older age was associated with lower baseline BMI (B = -0.19, SE = 0.05, p < .001), as was higher education (B = -0.34, SE = 0.09, p < .001). Further, higher education was associated with a slower decline in BMI before MCI (B = 0.02, SE = 0.006, p = .001), but a faster decline after MCI (B = -0.06, SE = 0.022, p = .003).

CONCLUSIONS

These results suggest an accelerated decline in BMI following an MCI diagnosis, with higher education related to an even faster BMI decline.

Availability of Cognitive Resources in Early Life Predicts Transitions Between Cognitive States in Middle and Older Adults From Europe

Background and Objectives

The existing literature highlights the importance of reading books in middle-to-older adulthood for cognitive functioning; very few studies, however, have examined the importance of childhood cognitive resources for cognitive outcomes later in life.

Research Design and Methods

Using data from 11 countries included in the Survey of Health, Ageing, and Retirement in Europe (SHARE) data set (N = 32,783), multistate survival models (MSMs) were fit to examine the importance of access to reading material in childhood on transitions through cognitive status categories (no cognitive impairment and impaired cognitive functioning) and death. Additionally, using the transition probabilities estimated by the MSMs, we estimated the remaining years of life without cognitive impairment and total longevity. All models were fit individually in each country, as well as within the pooled SHARE sample.

Results

Adjusting for age, sex, education, and childhood socioeconomic status, the overall pooled estimate indicated that access to more books at age 10 was associated with a decreased risk of developing cognitive impairment (adjusted hazard ratio = 0.79, confidence interval: 0.76-0.82). Access to childhood books was not associated with risk of transitioning from normal cognitive functioning to death, or from cognitive impairment to death. Total longevity was similar between participants reporting high (+1 standard deviation [SD]) and low (-1 SD) number of books in the childhood home; however, individuals with more access to childhood books lived a greater proportion of this time without cognitive impairment.

Discussion and Implications

Findings suggest that access to cognitive resources in childhood is protective for cognitive aging processes in older adulthood.

Leisure-Time Television Viewing and Computer Use, Family History, and Incidence of Dementia

INTRODUCTION

Time spent on screen-based sedentary activities is significantly associated with dementia risk, however, whether the associations vary by family history (FHx) of dementia is currently unknown. We aimed to examine independent associations of two prevalent types of screen-based sedentary activities (television [TV] viewing and computer use) with dementia and assess the modifying effect of FHx.

METHODS

We included 415,048 individuals free of dementia from the UK Biobank. Associations of TV viewing, computer use, and FHx with dementia risk were determined using Cox regression models. We estimated both multiplicative- and additive-scale interactions between TV viewing and computer use and FHx.

RESULTS

During a median follow-up of 12.6 years, 5,549 participants developed dementia. After adjusting for potential confounding factors, we observed that moderate (2-3 h/day; hazard ratio [HR] 1.13, 95% confidence interval 0.03-1.23) and high (>3 h/day; 1.33, 1.21-1.46) TV viewing was associated with a higher dementia risk, compared with low (0-1 h/day) TV viewing. Using restricted cubic spline models, the relationship of TV viewing with dementia was nonlinear (relative to 0 h/day; p for nonlinear = 0.005). We found that >3 h/day of TV viewing was associated with a 42% (1.42, 1.18-1.71) higher dementia risk in participants with FHx while a 30% (1.30, 1.17-1.45) in those without FHx. For computer use, both low (0 h/day; 1.41, 1.33-1.50) and high (>2 h/day; 1.17, 1.05-1.29) computer use were associated with elevated dementia risk, compared with moderate (1-2 h/day) computer use. We observed a J-shaped relationship with dementia (relative to 2 h/day; p for nonlinear <0.001). Compared with 1-2 h/day of computer use, the HRs of dementia were 1.46 (1.29-1.65) and 1.10 (0.90-1.36) for 0 h/day and >2 h/day of computer use in participants with FHx, respectively, while the corresponding HRs were 1.40 (1.30-1.50) and 1.19 (1.06-1.33) in those without FHx. We observed a positive additive interaction (RERI 0.29, 0.06-0.53) between computer use and FHx, while little evidence of interaction between TV viewing and FHx.

CONCLUSIONS

The time spent on TV viewing and computer use were independent risk factors for dementia, and the adverse effects of computer use and FHx were additive. Our findings point to new behavioral targets for intervention on preventing an early onset of dementia, especially for those with FHx.

Life Experience Matters: Enrichment and Stress Can Influence the Likelihood of Developing Alzheimer's Disease via Gut Microbiome

Alzheimer's disease (AD) is a chronic neurodegenerative disease, characterized by the presence of β-amyloid (Aβ) plaques and neurofibrillary tangles (NFTs) formed from abnormally phosphorylated tau proteins (ptau). To date, there is no cure for AD. Earlier therapeutic efforts have focused on the clinical stages of AD. Despite paramount efforts and costs, pharmaceutical interventions including antibody therapies targeting Aβ have largely failed. This highlights the need to alternate treatment strategies and a shift of focus to early pre-clinical stages. Approximately 25-40% of AD cases can be attributed to environmental factors including chronic stress. Gut dysbiosis has been associated with stress and the pathogenesis of AD and can increase both Aβ and NFTs in animal models of the disease. Both stress and enrichment have been shown to alter AD progression and gut health. Targeting stress-induced gut dysbiosis through probiotic supplementation could provide a promising intervention to delay disease progression. In this review, we discuss the effects of stress, enrichment, and gut dysbiosis in AD models and the promising evidence from probiotic intervention studies.

Cognitive Activity Is Associated with Cognitive Function over Time in a Diverse Group of Older Adults, Independent of Baseline Biomarkers

BACKGROUND

More frequent engagement in cognitive activity is associated with better cognitive function in older adults, but the mechanism of action is not fully understood. Debate remains whether increased cognitive activity provides a meaningful benefit for cognitive health or if decreased cognitive activity represents a prodrome of cognitive impairment. Neurological biomarkers provide a novel way to examine this relationship in the context of cognitive aging.

METHODS

We examined the association of self-reported cognitive activity, cognitive function, and concentrations of three biomarkers in community-dwelling participants of a longitudinal, population-based study. Cognitive activity was measured at baseline by asking participants to rate the frequency of 7 activities: (1) viewing television, (2) listening to the radio, (3) visiting a museum, (4) playing games, such as cards, checkers, crosswords, or other puzzles or games, (5) reading books, (6) reading magazines, and (7) reading newspapers. Cognitive function was measured with a battery of four tests (Mini-Mental State Examination, Digit Symbol Test, and the immediate and delayed recall of the East Boston Test) averaged into a composite score. At baseline, we evaluated the concentration of total tau (tau), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP).

RESULTS

The study sample comprised 1,168 older participants, primarily non-Hispanic Blacks (60%) and women (63%). At baseline, they were an average of 77 years old with 12.6 years of education. Mixed-effects models showed that cognitive activity was associated with better cognitive functioning at baseline and over time. These relationships remained after each biomarker was added to the model. Over an average of 6.4 years of follow-up, cognitive activity was associated with cognitive decline in the model with tau (estimate = 0.0123; p value = 0.03) and was mildly attenuated in the models with NfL (estimate = 0.0110; p value = 0.06) and GFAP (estimate = 0.0111; p value = 0.06). Biomarkers did not modify the association between cognitive activity and cognitive function over time.

CONCLUSION

The benefits of cognitive activity on cognition appear to be independent of biomarkers: tau, NfL, and GFAP, measured at baseline. More frequent cognitive activity may benefit the cognitive health of older adults with a wide range of potential disease risk and presentations.

Leisure Activities and the Risk of Dementia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Leisure activities are major components of modifiable and healthy lifestyles and are proposed to help prevent the development of dementia. This study aimed to assess the effects of different types of leisure activities, including cognitive, physical, and social activities, on the incidence of all-cause dementia (ACD), Alzheimer disease (AD), and vascular dementia (VD).

METHODS

We performed a systematic review and meta-analysis of the Cochrane, PubMed, Embase, and Web of Science databases to identify longitudinal studies that examined associations between leisure activities and dementia. Relative risks (RRs) and 95% CIs were pooled using random-effects meta-analysis. Subgroup analyses were used to estimate potential effect modifiers. The study was registered with PROSPERO (CRD42019116857).

RESULTS

A total of 38 longitudinal studies, with 2,154,818 participants at baseline, 74,700 ACD cases, 2,848 AD cases, and 1,423 VD cases during follow-up, were included in the meta-analysis. The subgroup analyses showed that physical (RR 0.83, 95% CI 0.78-0.88), cognitive (RR 0.77; 95% CI 0.68-0.87), and social (RR 0.93; 95% CI 0.87-0.99) activities were associated with a decreased incidence of ACD. In addition, physical (RR 0.87; 95% CI 0.78-0.96) and cognitive (RR 0.66; 95% CI 0.52-0.85) activities were related to a reduced risk of AD. Physical activity (RR 0.67; 95% CI 0.53-0.85) was associated with a lower incidence of VD.

DISCUSSION

Our findings suggest that leisure activities are inversely associated with a risk of ACD, AD, and VD.

Association Between TBI-Related Hearing Impairment and Cognition: A TRACK-TBI Study

OBJECTIVE

To examine the association between hearing impairment and cognitive function after traumatic brain injury (TBI).

SETTING

A total of 18 level I trauma centers throughout the United States in the T ransforming R esearch a nd C linical K nowledge in TBI (TRACK-TBI) study.

PARTICIPANTS

From February 2014 to June 2018, a total of 2697 participants with TBI were enrolled in TRACK-TBI. Key eligibility criteria included external force trauma to the head, presentation to a participating level I trauma center, and receipt of a clinically indicated head computed tomographic (CT) scan within 24 hours of injury. A total of 1267 participants were evaluated in the study, with 216 participants with hearing impairment and 1051 participants without hearing impairment. Those with missing or unknown hearing status or cognitive assessment were excluded from analysis.

DESIGN

Prospective, observational cohort study.

MAIN MEASURES

Hearing impairment at 2 weeks post-TBI was based on self-report. Participants who indicated worse hearing in one or both ears were defined as having hearing impairment, whereas those who denied worse hearing in either ear were defined as not having hearing impairment and served as the reference group. Cognitive outcomes at 6 months post-TBI included executive functioning and processing speed, as measured by the Trail Making Test (TMT) B/A and the Wechsler Adult Intelligence Scale, Fourth Edition, Processing Speed Index subscale (WAIS-IV PSI), respectively.

RESULTS

TBI-related hearing impairment had a small but significantly greater TMT B/A ratio than without TBI-related hearing impairment: mean difference ( B ) = 0.25; 95% CI, 0.07 to 0.43; P = .005. No significant mean differences on WAIS-IV PSI scores were found between participants with and without TBI-related hearing impairment: B = 0.36; 95% CI, -2.07 to 2.60; P = .825.

CONCLUSION

We conclude that TBI-related hearing impairment at 6 months postinjury was significantly associated with worse executive functioning but not cognitive processing speed.

Dietary Regulation of Gut-Brain Axis in Alzheimer's Disease: Importance of Microbiota Metabolites

Alzheimer's disease (AD) is a neurodegenerative disease that impacts 45 million people worldwide and is ranked as the 6th top cause of death among all adults by the Centers for Disease Control and Prevention. While genetics is an important risk factor for the development of AD, environment and lifestyle are also contributing risk factors. One such environmental factor is diet, which has emerged as a key influencer of AD development/progression as well as cognition. Diets containing large quantities of saturated/trans-fats, refined carbohydrates, limited intake of fiber, and alcohol are associated with cognitive dysfunction while conversely diets low in saturated/trans-fats (i.e., bad fats), high mono/polyunsaturated fats (i.e., good fats), high in fiber and polyphenols are associated with better cognitive function and memory in both humans and animal models. Mechanistically, this could be the direct consequence of dietary components (lipids, vitamins, polyphenols) on the brain, but other mechanisms are also likely to be important. Diet is considered to be the single greatest factor influencing the intestinal microbiome. Diet robustly influences the types and function of micro-organisms (called microbiota) that reside in the gastrointestinal tract. Availability of different types of nutrients (from the diet) will favor or disfavor the abundance and function of certain groups of microbiota. Microbiota are highly metabolically active and produce many metabolites and other factors that can affect the brain including cognition and the development and clinical progression of AD. This review summarizes data to support a model in which microbiota metabolites influence brain function and AD.

The hybrid compounds as multi-target ligands for the treatment of Alzheimer's Disease: Considerations on Donepezil

The strategies to combat Alzheimer's Disease (AD) have been changing with respect to the failures of many drug candidates assessed in clinical studies, the complex pathophysiology of AD, and the limitations of the current drugs employed. So far, none of the targets, either validated or nonvalidated, have been shown to be purely causative in the generation and development of AD. Considering the progressive and the neurodegenerative characteristics of the disease, the main strategy has been based on the design of molecules capable of showing activity on more than one receptor, and it is defined as multi-target ligand design strategy. The hybrid molecule concept is an outcome of this approach. Donepezil, as one of the currently employed drugs for AD therapy, has also been utilized in hybrid drug design studies. This review has aimed to present the promising donepezil-like hybrid molecules introduced in the recent period. Particularly, multi-target ligands with additional activities concomitant to cholinesterase inhibition are preferred.

Protective Effect of Patchouli Alcohol Against SH-SY5Y Cell Injury Induced by Aβ25-35 via the Reduction of Oxidative Stress and Apoptosis

Patchouli alcohol (PA) has multiple pharmacological activities, but its protective effect against SH-SY5Y cell injury induced by Aβ25-35 has not been reported. It has been recorded that phosphatidylinositol 3-hydroxykinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway plays an important role in neuroprotection. The purpose of this study was to investigate the protective effect of PA against SH-SY5Y cell injury induced by Aβ25-35 and its underlying mechanism. The results showed that compared with that in the Aβ25-35-induced injury group, the survival rate of SH-SY5Y cells increased ( P < .01) in the different PA-treated groups and the lactic dehydrogenase activity decreased significantly ( P < .01) in the 10, 20, and 40 μg/mL PA groups; compared with those in the Aβ25-35-induced injury group, the malonyldialdehyde contents in SH-SY5Y cells decreased ( P < .05 or P < .01), while the superoxide dismutase, glutathione peroxidase, and catalase activities increased significantly ( P < .05 or P < .01) in the different PA-treated groups; compared with those in the Aβ25-35-induced injury group, the apoptosis rates, and the mRNA and protein levels of Caspase-3 and Bax in SH-SY5Y cells decreased ( P < .05 or P < .01), while the mRNA and protein levels of Bcl-2, and phosphorylated Akt (p-Akt) and phosphorylated mTOR protein levels increased significantly ( P < .05 or P < .01) in the different PA-treated groups. The above results indicate that PA can inhibit the oxidative stress and apoptosis of SH-SY5Y cells induced by Aβ25-35 by regulating the PI3K/Akt/mTOR pathway, to protect the SH-SY5Y cells from the injury induced by Aβ25-35.

Watching TV and Cognition: The SPAH 2-Year Cohort Study of Older Adults Living in Low-Income Communities

Watching TV is a highly prevalent leisure activity among older adults and, in many cases, the only leisure option of those living in low-income communities. While engaging in leisure activities have proven to protect older adults from cognitive decline, the effects of watching TV on cognition of this population is controversial in the literature. This study investigated the impact of watching TV on global cognitive function, immediate memory, verbal fluency, risk of dementia of amnestic mild cognitive impairment (aMCI) in a cohort of older adults residents of socioeconomically deprived areas of São Paulo, Brazil. We used data from the São Paulo Aging & Health Study (SPAH). Participants aged 65 years or over, with no dementia diagnosis at baseline and who completed the 2-year follow-up assessment were included in this study (n = 1,243). Multivariable linear regression models were performed to assess the effect of watching TV on global cognitive function, immediate memory and verbal fluency. Multivariable logistic regression models were used to evaluate the risk of developing dementia and aMCI. Models were controlled by cognitive performance at baseline, sociodemographic characteristics and functional status. Cognitive performance at baseline and follow-up were similar. Thirty-one participants were diagnosed with dementia, and 23 with aMCI 24 months after inclusion in the study. Watching TV did not show any positive or negative effect on global cognitive function, immediate memory, verbal fluency, risk of dementia and risk of aMCI. It is good news that watching TV did not predict the decline in cognition in elders. However, it is essential to increase opportunities for other leisure activities for low-income and low-educated older adults if we do consider that leisure activities protect cognition decline in older adults. In the coming decades, developing countries will experience the highest burden of dementia and more than fun, public policies to promote leisure activities might be a strategy to alleviate this burden shortly.

Effectiveness of a chess-training program for improving cognition, mood, and quality of life in older adults: A pilot study

BACKGROUND

Regular practice of a cognitively stimulating activity, such as chess, can help maintain a healthy cognitive, social, and psychological state during the aging process.

OBJECTIVE

To evaluate the effects of a chess-training program on cognitive status, mood, and quality of life (QoL) in a sample of institutionalized and semi-institutionalized older adults.

METHOD

A nonrandomized, controlled pilot study with repeated measures (pre- and post-intervention) was conducted.

RESULTS

Analyses revealed a positive impact of the chess program on general cognitive status (p < 0.001) and promising evidence (p < 0.043) of an impact on attention, processing speed, and executive functions. The participants in the intervention group also showed significant improvement in QoL scores (p < 0.021).

CONCLUSIONS

A 12-week chess-training protocol with two 60-minute sessions per week improved cognition and QoL in a sample of institutionalized and semi-institutionalized older adults. Further research with larger samples is needed to explore its effects in depth.

Trends in the prevalence of cognitive impairment in Chinese older adults: based on the Chinese Longitudinal Healthy Longevity Survey cohorts from 1998 to 2014

In the context of a rapidly ageing Chinese population, this study aims to examine trends in the prevalence of cognitive impairment among people ≥65 y of age in China. Our sample is 72 821 adults aged 65–105 y from the seven waves of the Chinese Longitudinal Healthy Longevity Survey, a national mixed longitudinal cohort. The Chinese version of the Mini-Mental State Examination was used to measure CI. Risk factor-adjusted prevalence trend was examined using multilevel regression models. Age-standardized prevalence of cognitive impairment increased from 11.00% in 1998 to 11.84% in 2008 and decreased to 8.88% in 2014. Older age, female gender, less education, rural residence, not married, lack of physical and cognitive activities, suffering from stroke, vision and hearing impairment, and activities of daily living disability were negatively associated with cognitive impairment. Our study suggests a decreasing trend of cognitive impairment prevalence in China. However, whether decreasing prevalence will contribute to a reduced burden of cognitive impairment given the ageing of the population is unknown.

Is Engagement in Intellectual and Social Leisure Activities Protective Against Dementia Risk? Evidence from the English Longitudinal Study of Ageing

Background:

Studies have suggested that mentally stimulating activities and socially engaged lifestyles may reduce dementia risk; however, it is unclear which activities are more beneficial.

Objective:

We investigated intellectual and social leisure activities in relation to dementia incidence and explored the modifying role of sex and marital status in these associations.

Methods:

The sample was comprised of 8,030 participants aged 50+ from the English Longitudinal Study of Ageing, who joined at wave 1 (2002-2003), or waves 3 (2006-2007), or 4 (2008-2009). The end of the study period was wave 8 (2016-2017). Subdistribution hazard models investigated the role of leisure activities grouped into intellectual and social domains in relation to dementia while accounting for the risk of death. Subsequent analyses were conducted with individual leisure activities.

Results:

During the study period of up to 15 years, 412 participants developed dementia, and 2,192 died. We found that increased engagement in the intellectual activities’ domain was associated with a decreased dementia incidence (SHR 0.85, 95% CI 0.76–0.96, p = 0.007), independent of the risk of death in married individuals, but not in those who were single, divorced, or widowed. Individual analyses for each leisure activity showed independent associations for reading newspapers in females (SHR 0.65, 95% CI 0.49–0.84, p = 0.001), mobile phone usage in males (SHR 0.61, 95% CI 0.45–0.84, p = 0.002), and having hobbies for married individuals (SHR 0.70, 95% CI 0.51–0.95, p = 0.02).

Conclusion:

We found that intellectual leisure activities contribute to lower dementia risk in a representative population of English adults, suggesting intervention opportunities.

Association of combined engagement in cognitive and physical activity with domain-specific cognitive function: The Shanghai Aging Study

OBJECTIVES

This cross-sectional study aimed to examine the association of the combined engagement in cognitive activity (CA) and physical activity (PA) with domain-specific cognition in community-dwelling older adults.

METHODS

We analysed data from 3192 dementia-free participants aged ≥50 years in the Shanghai Aging Study. CA was assessed using Shanghai Cognitive Activities Scale. PA was determined based on questionnaires and further transformed into metabolic equivalent values. We used multivariate linear and logistic regression models to estimate the β and odds ratio of CA, PA, or combined CA and PA and each neuropsychological test.

RESULTS

A high level of CA was associated with a better performance in most of the tests, except for the conflicting instructions task (CIT) and stick test (ST). In contrast, PA displayed no significant associations with any test. Engagement in high CA and high PA was associated with the best performance in Mini-Mental State Examination, recall in ST, categorisation in Modified Common Objects Sorting Test (MCOST), immediate recall, delayed recall, and recognition in Auditory Verbal Learning Test. Participants with "high CA and low PA" had the lowest risk of impairment in Go/No-Go correct tapping in CIT, rotate in ST, item naming, and category naming in MCOST, Trail Making Test (TMT)-A, and TMT-B.

CONCLUSIONS

Our study suggests that engagement in both high CA and high PA may be the most efficacious way to maintain various domains of cognition. A higher level of CA may help to preserve cognition among older individuals who have difficulties in performing PA.

Intelligence trajectories in adolescents and adults with down syndrome: Cognitively stimulating leisure activities mitigate health and ADL problems

GOALS

This study examined: (a) crystallized/fluid intelligence trajectories of adolescents and adults with Down syndrome; and (b) the contribution of endogenous (health, activities of daily living-ADL) and exogenous (cognitively stimulating leisure activities) factors on adults' intelligence with age.

METHOD

Four cohorts (N = 80) with Down syndrome participated: adolescents (ages 16-21) and adults (ages 30-45, 46-60 and 61+). All completed Vocabulary and Similarities (crystallized) and Block Design and Raven (fluid) intelligence tests (WAIS-III^HEB , Wechsler, 2001).

RESULTS

The 30-45 cohort significantly outperformed the 16-21 cohort. Except for Vocabulary, which remained stable, onset of decline was at 40-50. Age-related declining health and ADL correlated with participants' lower fluid intelligence, but cognitive leisure activities mitigated this influence.

CONCLUSIONS

Intelligence development into adulthood supported the continuous trajectory and compensation age theory, rather than accelerated or stable trajectories. Not only endogenous factors but also exogenous factors determined intelligence levels in adults with Down syndrome, supporting cognitive activity theory.

Effectiveness of neurobic exercise program on memory and depression among elderly residing at old age home

Objectives This study finds out the effectiveness of neurobic exercise program on memory and depression among elderly residing in old age homes. Methods The non-probability purposive sampling technique was used for sample selection. Wechsler's memory scale (WMS-IV) and Geriatric depression scale (GDS) were the instruments used to assess the memory and depression among elderly during the pretest and posttest, respectively and the researcher had developed data sheet to collect information about the background variables using interview technique. Results The neurobic exercise program was found to be effective in reducing depression among elderly residing in old age homes. There was a significant difference (p<0.001) in the level of depression had been found during the pretest and posttest in the interventional group. There was a statistically significant difference (p<0.001) found between the study group and in the control group. There was significant correlation (r=0.417, p<0.05) found between the memory and depression during the pretest in the study group among the elderly. A statistically significant association (p<0.05) found in the mean scores of depression and marital status of the elderly during the pretest in the study group and there was a significant association (p<0.01) found in the mean scores of depression and the gender of the elderly during the pretest and posttest in the non interventional group were found. Conclusions The findings suggested that neurobic exercise program is an effective intervention in improving memory and reducing depression.

Identifying a task-invariant cognitive reserve network using task potency

Cognitive reserve (CR) is thought to protect against the consequence of age- or disease-related structural brain changes across multiple cognitive domains. The neural basis of CR may therefore comprise a functional network that is actively involved in many different cognitive processes. To investigate the existence of such a "task-invariant" CR network, we measured functional connectivity in a cognitively normal sample between 20 and 80 years old (N ​= ​265), both at rest and during the performance of 11 separate tasks that aim to capture four latent cognitive abilities (i.e. vocabulary, episodic memory, processing speed, and fluid reasoning). For each individual, we determined the change in functional connectivity from the resting state to each task state, which is referred to as "task potency" (Chauvin et al., 2018, 2019). Task potency was calculated for each pair among 264 nodes (Power et al., 2012) and then summarized across tasks reflecting the same cognitive ability. Subsequently, we established the correlation between task potency and IQ or education (i.e. CR factors). We identified a set of 57 pairs in which task potency showed significant correlations with IQ, but not education, across all four cognitive abilities. These pairs were included in a principal component analysis, from which we extracted the first component to obtain a latent variable reflecting task potency in this task-invariant CR network. This task potency variable was associated with better episodic memory (β ​= ​0.19, p ​< ​.01) and fluid reasoning performance (β ​= ​0.17, p ​< ​.01) above and beyond the effects of cortical thickness (range [absolute] β ​= ​0.28-0.32, p ​< ​.001). Our identification of this task-invariant network contributes to a better understanding of the mechanism underlying CR, which may facilitate the development of CR-enhancing treatments. Our work also offers a useful alternative operational measure of CR for future studies.

Association of Physical Activity and Cognitive Activity With Disability: A 2-Year Prospective Cohort Study

OBJECTIVE

Engaging in physical activity (PA) and/or cognitive activity (CA) retains function in older adults, but whether the combination of these activities is associated with disability onset is still unknown. This study aimed to examine the prospective association of PA and/or CA with disability onset in older adults.

METHODS

This was an ongoing prospective community-based cohort study. Data collection was conducted through a health check. An analyzable sample of 2668 participants (mean age = 75.5 years; 51.6% female) were categorized into 4 groups based on quartile 1 (low) and 2 to 4 (high) values of accelerometer-measured moderate-to-vigorous PA and CA scale scores based on the frequency of 6 activities including reading, writing for pleasure, doing crossword puzzles, and playing board games or cards. Disability onset was monitored through long-term care insurance certification for at least 2 years.

RESULTS

A log-rank test showed significantly lower incidence of disability in the high PA and low CA group and the high PA and high CA group compared with the low PA and low CA group. Cox-proportional hazards models (referring to the low PA and low CA group) showed that only the high PA and high CA group was significantly associated with a lowered hazard ratio for disability onset (0.51; 95% CI = 0.29-0.90) after adjusting for covariates.

CONCLUSIONS

Engaging in both PA and CA is effective for reducing risk of disability onset, but engaging in either PA or CA is not effective.

IMPACT

Physical therapists can be guided by this research to design intervention strategies for people at risk of disability.

Self-reported Lifestyle Activities in Relation to Longitudinal Cognitive Trajectories

BACKGROUND

Few studies have examined the relationship between lifestyle activity engagement and cognitive trajectories among individuals who were cognitively normal at baseline.

OBJECTIVE

To examine the relationship of current engagement in lifestyle activities to previous cognitive performance among individuals who were cognitively normal at baseline, and whether this relationship differed for individuals who subsequently developed mild cognitive impairment (MCI), or by APOE-4 genotype, age, and level of cognitive reserve.

METHODS

Participants (N=189) were primarily middle-aged (M=56.6 y) at baseline and have been prospectively followed with annual assessments (M follow-up=14.3 y). Engagement in physical, cognitive, and social activities was measured by the CHAMPS activity questionnaire. Longitudinal cognitive performance was measured by a global composite score.

RESULTS

Among individuals who progressed to MCI (n=27), higher lifestyle activity engagement was associated with less decline in prior cognitive performance. In contrast, among individuals who remained cognitively normal, lifestyle activity engagement was not associated with prior cognitive trajectories. These effects were largely independent of APOE-4 genotype, age, and cognitive reserve.

CONCLUSIONS

Greater engagement in lifestyle activities may modify the rate of cognitive decline among those who develop symptoms of MCI, but these findings need to be confirmed in prospective studies.

Brain Ventricular System and Cerebrospinal Fluid Development and Function: Light at the End of the Tube: A Primer with Latest Insights

The brain ventricular system is a series of connected cavities, filled with cerebrospinal fluid (CSF), that forms within the vertebrate central nervous system (CNS). The hollow neural tube is a hallmark of the chordate CNS, and a closed neural tube is essential for normal development. Development and function of the ventricular system is examined, emphasizing three interdigitating components that form a functional system: ventricle walls, CSF fluid properties, and activity of CSF constituent factors. The cellular lining of the ventricle both can produce and is responsive to CSF. Fluid properties and conserved CSF components contribute to normal CNS development. Anomalies of the CSF/ventricular system serve as diagnostics and may cause CNS disorders, further highlighting their importance. This review focuses on the evolution and development of the brain ventricular system, associated function, and connected pathologies. It is geared as an introduction for scholars with little background in the field.

Differential effects of cognitive training modules in healthy aging and mild cognitive impairment: A comprehensive meta-analysis of randomized controlled trials

This meta-analysis was designed to compare the effectiveness of 2 cognitive training modules, single-component training, which targets 1 specific cognitive ability, versus multicomponent training, which trains multiple cognitive abilities, on both trained abilities (near transfer) and untrained abilities (far transfer) in older adults. The meta-analysis also assessed whether individual differences in mental status interacted with the extent of transfer. Eligible randomized controlled trials (215 training studies) examined the immediate effects of cognitive training in either healthy aging (HA) or mild cognitive impairment (MCI). Results yielded an overall net-gain effect size (g) for the cognitive training of 0.28 (p < .001). These effects were similar across mental status and training modules, and were significant for both near (g = 0.37) and far (g = 0.22) transfer. Although all training modules yielded significant near transfer, only a few yielded significant far transfer. Single-component training of executive functions was most effective on near and far transfer, with processing speed training improving everyday functioning. All modules of multicomponent training (specific and nonspecific) yielded significant near and far transfer, including everyday functioning. Training effects on cognition were moderated by educational attainment and number of cognitive outcomes, but only in HA. These findings suggest that, in older adults, all modules of multicomponent training are more effective in engendering near and far transfer, including everyday functioning, when compared with single-component training modules. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The cross-sectional association of cognitive stimulation factors and cognitive function among Latino adults in Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

INTRODUCTION

Higher cognitive stimulation (CS) is associated with improved cognition. Sources of CS among Hispanics/Latinos are understudied.

METHODS

In the Hispanic Community Health Study/Study of Latinos 2008 to 2011 (n = 9438), we used finite mixture models to generate latent CS profiles, and multivariate linear regressions to examine associations with cognition in Hispanic/Latino adults (45-74 years). CS included education, occupation, social network, and acculturation. Cognitive measures included the Six-Item Screener, Brief-Spanish English Verbal Learning Test Sum and Recall, Controlled Oral Word Association Test, Digit Symbol Substitution, and Global Cognition.

RESULTS

Two CS profiles emerged, and were labeled "typical" and "enhanced." The enhanced CS profile (22%) had more family connections, bicultural engagements, skilled/professional occupations, education, and higher cognitive scores.

DISCUSSION

An enhanced CS profile emerged from contextual and culturally relevant factors, and was associated with higher cognitive scores across all measures. This provides initial evidence on how factors coalesce to shape cognitive protection in Hispanics/Latinos.

A Novel Therapeutic Approach to Treat Alzheimer's Disease by Neurotrophic Support During the Period of Synaptic Compensation

Alzheimer’s disease (AD), at present, is considered an incurable disease and a major dilemma with no drug to stop or slow down its progression. Drugs that are currently available in the market are able to only transiently improve the clinical symptoms. The repeated failures in developing an effective drug has led to the suggestion that the medical intervention was probably too late to be effective since the pathology starts many years before the appearance of the clinical symptoms. Probably, at the time of the appearance of clinical symptoms the brain has undergone major neuronal and synaptic loss. Because of the uncertainty on when to use a prevention therapy, especially targeting amyloid-β (Aβ) and tau pathologies, interventions that rely on the regenerative capacity of the brain such as the modulation of the inherent neurogenesis and neuronal plasticity represent a promising therapeutic strategy. Such an approach can act both at early as well as late stages of the disease and remove the barrier of the time of intervention. In this article, we review studies mainly from our laboratory that show the merit of early intervention during the synaptic and neuronal compensation period where the brain still has the capacity to self-repair by offering neurotrophic support in reversing cognitive impairment, neuronal and synaptic deficits, Aβ, and tau pathologies and decreasing mortality in a transgenic mouse model of AD.

Computerised cognitive training for preventing dementia in people with mild cognitive impairment

BACKGROUND

The number of people living with dementia is increasing rapidly. Clinical dementia does not develop suddenly, but rather is preceded by a period of cognitive decline beyond normal age-related change. People at this intermediate stage between normal cognitive function and clinical dementia are often described as having mild cognitive impairment (MCI). Considerable research and clinical efforts have been directed toward finding disease-modifying interventions that may prevent or delay progression from MCI to clinical dementia.

OBJECTIVES

To evaluate the effects of at least 12 weeks of computerised cognitive training (CCT) on maintaining or improving cognitive function and preventing dementia in people with mild cognitive impairment.

SEARCH METHODS

We searched to 31 May 2018 in ALOIS (www.medicine.ox.ac.uk/alois) and ran additional searches in MEDLINE, Embase, PsycINFO, CINAHL, ClinicalTrials.gov, and the WHO portal/ICTRP (www.apps.who.int/trialsearch) to identify published, unpublished, and ongoing trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in which cognitive training via interactive computerised technology was compared with an active or inactive control intervention. Experimental computerised cognitive training (CCT) interventions had to adhere to the following criteria: minimum intervention duration of 12 weeks; any form of interactive computerised cognitive training, including computer exercises, computer games, mobile devices, gaming console, and virtual reality. Participants were adults with a diagnosis of mild cognitive impairment (MCI) or mild neurocognitive disorder (MND), or otherwise at high risk of cognitive decline.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias of the included RCTs. We expressed treatment effects as mean differences (MDs) or standardised mean differences (SMDs) for continuous outcomes and as risk ratios (RRs) for dichotomous outcomes. We used the GRADE approach to describe the overall quality of evidence for each outcome.

MAIN RESULTS

Eight RCTs with a total of 660 participants met review inclusion criteria. Duration of the included trials varied from 12 weeks to 18 months. Only one trial used an inactive control. Most studies were at unclear or high risk of bias in several domains. Overall, our ability to draw conclusions was hampered by very low-quality evidence. Almost all results were very imprecise; there were also problems related to risk of bias, inconsistency between trials, and indirectness of the evidence.No trial provided data on incident dementia. For comparisons of CCT with both active and inactive controls, the quality of evidence on our other primary outcome of global cognitive function immediately after the intervention period was very low. Therefore, we were unable to draw any conclusions about this outcome.Due to very low quality of evidence, we were also unable to determine whether there was any effect of CCT compared to active control on our secondary outcomes of episodic memory, working memory, executive function, depression, functional performance, and mortality. We found low-quality evidence suggesting that there is probably no effect on speed of processing (SMD 0.20, 95% confidence interval (CI) -0.16 to 0.56; 2 studies; 119 participants), verbal fluency (SMD -0.16, 95% CI -0.76 to 0.44; 3 studies; 150 participants), or quality of life (mean difference (MD) 0.40, 95% CI -1.85 to 2.65; 1 study; 19 participants).When CCT was compared with inactive control, we obtained data on five secondary outcomes, including episodic memory, executive function, verbal fluency, depression, and functional performance. We found very low-quality evidence; therefore, we were unable to draw any conclusions about these outcomes.

AUTHORS' CONCLUSIONS

Currently available evidence does not allow us to determine whether or not computerised cognitive training will prevent clinical dementia or improve or maintain cognitive function in those who already have evidence of cognitive impairment. Small numbers of trials, small samples, risk of bias, inconsistency between trials, and highly imprecise results mean that it is not possible to derive any implications for clinical practice, despite some observed large effect sizes from individual studies. Direct adverse events are unlikely to occur, although the time and sometimes the money involved in computerised cognitive training programmes may represent significant burdens. Further research is necessary and should concentrate on improving methodological rigour, selecting suitable outcomes measures, and assessing generalisability and persistence of any effects. Trials with long-term follow-up are needed to determine the potential of this intervention to reduce the risk of dementia.

Associated factors for cognition of physically independent elderly people living in residential care facilities for the aged in Sri Lanka

BACKGROUND

As the elderly population and prevalence of dementia is increasing, it is necessary to have a better comprehension of the influence of specific factors on cognitive function. Dementia is not an inevitable consequence of ageing. Lifestyle factors might either increase or decrease the risk. Even though different studies have focused on individual factors, only a few studies are available which assess all these factors as a whole. Available evidence on these factors is mainly from high income countries and much less evidence is available from low and middle income countries. As cognition is critical for elderly people to engage in a physically independent life, we aimed to identify the associated factors of cognition.

METHODS

This was a descriptive cross sectional study performed with 421 elderly people dwelling in residential care facilities for the aged in two selected districts in the Southern Province of Sri Lanka. Cognition was assessed using the Mini Mental State Examination (MMSE). Independent sample t test, ANOVA and regression analyses were used to explore associated factors for cognition. The statistical significance was kept at bonferroni adjusted p < 0.004.

RESULTS

The study included elderly people with a mean age of 71.9 ± 6.7 years and of them 65.8% were females. Factors affecting higher level of cognition were, having upper secondary, advanced and higher education; being married; arriving at the facility on one's own accord; being visited by family members; higher physical activity levels and engaging in social and leisure activities (p < 0.004). The factors, namely physical activity level, educational status, visits by family members and engaging in leisure activities were the predictors of cognition in the regression model.

CONCLUSION

Though there were several factors that associated with the level of cognition such as educational status, marital status, reason for attending the facility, visits by family members, physical activity levels and participation in social and leisure activities, only the factors, such as physical activity levels, visits by family members, educational status and engaging in leisure activities were the predictors of cognition.

Antecedents and consequences of unawareness of memory impairment in dementia

OBJECTIVE

To assess the prevalence, antecedents, and consequences of unawareness of memory impairment in dementia.

METHOD

Persons (n = 1,862) from a geographically defined community without dementia at enrollment subsequently underwent clinical classification (248 with dementia, 611 with mild cognitive impairment, 1,003 with no cognitive impairment), memory testing, and self-appraisal of memory. Memory performance was regressed on self-appraised memory, and the residuals served as an index of memory awareness. After clinical classification, participants completed brief cognitive testing at 3-year intervals for up to 15 years.

RESULTS

When unawareness was defined as a score at or below thresholds ranging from the 15th to 25th percentiles, it was more common in dementia (67%-83%) and mild cognitive impairment (15%-33%) than in no cognitive impairment (2%-6%; all p < .001). A continuous measure of awareness (M = 0.00, SD = 0.61) was reduced by 0.37-unit in mild cognitive impairment (SE = 0.04, p < .001) and 1.04-unit in dementia (SE = 0.06), p < .001) compared with those without cognitive impairment, and these associations were weaker in Black persons than White persons (estimate for dementia by race = 0.37, SE = 0.12, p = .003; estimate for mild cognitive impairment by race = 0.30, SE = 0.08, p < .001). Higher premorbid neuroticism was associated with better memory awareness in dementia. Higher memory awareness was not related to mortality in mild cognitive impairment or dementia but had a marginal association with slower cognitive decline in mild cognitive impairment.

CONCLUSIONS

Unawareness of memory impairment is a common manifestation of dementia, particularly in White persons, but is not strongly related to adverse disease outcomes. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Association between social participation and incident risk of functional disability in elderly Japanese: The Ohsaki Cohort 2006

BACKGROUND

Although several longitudinal studies have examined the relationship between social participation and incident functional disability, the related mechanisms have remained unclear. The aim of this study was to examine the mechanisms linking social participation to incident functional disability.

METHODS

We analyzed follow-up data for 11,992 older adults (≥65 years) participating in a community-based, prospective cohort study covering a 9-year period. At the baseline, the subjects were asked about three types of participation in community activities (volunteering, hobbies, and neighborhood associations) and the frequency of their participation. Data on incident functional disability were retrieved from the public Long-term Care Insurance database. The Cox model was used to estimate the multivariate-adjusted hazard ratios of incident functional disability. We then conducted mediation analysis to assess the magnitude of the mediating effect.

RESULTS

Among 84,760 person-years of follow-up, there were 3,984 cases of incident functional disability. The hazard ratio was 0.79 (95% CI: 0.73-0.86) for participating in one type of activity, 0.82 (95% CI: 0.74-0.90) for two types of activity and 0.70 (95% CI: 0.64-0.77) for three types of activity in comparison with no participation in any activity. Among the estimated mediating effects, cognitive activity accounted for 9.3%, time spent walking for 8.3%, psychological state for 4.6%, and social support for 2.8% of the reduced risk of incident functional disability.

CONCLUSION

The results of this population-based cohort study indicate that cognitive activity and time spent walking are important mechanisms linking social participation to incident functional disability.

Modifiable dementia risk score to study heterogeneity in treatment effect of a dementia prevention trial: a post hoc analysis in the preDIVA trial using the LIBRA index

Background

Selecting high-risk participants for dementia prevention trials based on a modifiable dementia risk score may be advantageous, as it increases the opportunity for intervention. We studied whether a multi-domain intervention can prevent all-cause dementia and cognitive decline in older people across three different levels of a modifiable dementia risk score.

Methods

Prevention of Dementia by Intensive Vascular Care (preDIVA) is a randomised controlled trial studying the effect of multi-domain vascular care during 6–8 years on incident all-cause dementia in community-dwelling people aged 70–78 years. For this post hoc analysis, we stratified preDIVA participants in tertiles based on their baseline LIfestyle for BRAin Health (LIBRA) index, a modifiable dementia risk score. With Cox proportional hazards regression, the intervention effect on dementia was assessed. The effect on cognition was measured every 2 years with the Mini-Mental State Examination and Visual Association Test.

Results

Dementia developed in 220 of 3274 (6.7%) participants. In participants with a low, intermediate and high LIBRA index, the hazard ratio (HR) of the intervention on incident dementia was respectively 0.71 (95% CI 0.45–1.12), 1.06 (95% CI 0.66–1.69) and 1.02 (95% CI 0.64–1.62). Also, when adding the non-modifiable risk factors age, education and sex to the index, results were comparable (respectively HR 0.88, 95% CI 0.54–1.43; HR 0.91, 95% CI 0.57–1.47; HR 0.92, 95% CI 0.59–1.41). There was no statistically significant intervention effect on cognition during follow-up across the LIBRA groups.

Conclusions

In the preDIVA study population aged 70–78 years, the LIBRA modifiable dementia risk score did not identify a (high-)risk group in whom the multi-domain intervention was effective in preventing dementia or cognitive decline.

Trial registration

International Standard Randomised Controlled Trial Number registry, ISRCTN29711771. Registered on 14 February 2006.

Electronic supplementary material

The online version of this article (10.1186/s13195-018-0389-4) contains supplementary material, which is available to authorized users.

Effects of Cognitive Reserve on Cognitive Performance in a Follow-Up Study in Older Adults With Subjective Cognitive Complaints. The Role of Working Memory

Objective: Analyze the effects of CR on cognitive performance in adults with subjective cognitive complaints at follow-up. Method: We analyzed the factorial structure of the three constructs defined in cognitive performance (Episodic memory, Working memory, and General cognitive performance) separately to search for evidence of the invariance of the measurement model. We then developed four structural nested models to analyze the relationship between CR and cognitive performance, measured at baseline and after approximately 18 months, in 266 participants older than 50 years with subjective cognitive complaints. Results: The nested models revealed the following main results: direct effects of CR on all cognitive constructs at baseline and also indirect effects on the same constructs at follow-up, and indirect effects of CR on other cognitive constructs at follow-up via working memory at follow-up. Conclusion: The findings show that the proposed model is useful for measuring the influence of CR on cognitive performance in follow-up studies and that CR has a positive influence on cognitive performance at follow-up via working memory. CR may enhance mechanisms of information processing, favoring performance of tasks involving other cognitive constructs in older adults with subjective cognitive complaints.

Neighborhood Socioeconomic Status and Cognitive Trajectories in a Diverse Longitudinal Cohort

OBJECTIVES

Although individual-level socioeconomic status is associated with poor outcomes, less is known regarding how the social context might affect cognitive outcomes. We examined the effect of neighborhood socioeconomic status (NSES) on baseline cognitive function and trajectories of decline.

METHODS

The sample (N = 480) came from a longitudinal cohort recruited to study cognitive function. Mixed effects models examined the influence of NSES on baseline and rate of change in executive function, semantic memory, and episodic memory.

RESULTS

NSES was positively associated with semantic memory scores at baseline, but not with executive function or episodic memory in adjusted models, nor was it associated with cognitive change in longitudinal analyses. In exploratory analyses, for individuals with dementia, those with higher NSES declined faster in executive function and semantic memory than did those with lower NSES.

CONCLUSIONS

Results suggest that NSES has limited effects independent of personal characteristics; however, findings showed a complex relation of NSES and decline, with NSES effects observed only for individuals with dementia. Results are discussed in the context of cognitive reserve.

CLINICAL IMPLICATIONS

Clinical assessments of individuals who present with cognitive impairment might benefit from an understanding of the neighborhood context from which patients come.

A neuroimaging approach to capture cognitive reserve: Application to Alzheimer's disease

Cognitive reserve (CR) explains interindividual differences in the ability to maintain cognitive function in the presence of neuropathology. We developed a neuroimaging approach including a measure of brain atrophy and cognition to capture this construct. In a group of 511 Alzheimer's disease (AD) biomarker-positive subjects in different stages across the disease spectrum, we performed 3T magnetic resonance imaging and predicted gray matter (GM) volume in each voxel based on cognitive performance (i.e. a global cognitive composite score), adjusted for age, sex, disease stage, premorbid brain size (i.e. intracranial volume) and scanner type. We used standardized individual differences between predicted and observed GM volume (i.e. W-scores) as an operational measure of CR. To validate this method, we showed that education correlated with mean W-scores in whole-brain (r = -0.090, P < 0.05) and temporoparietal (r = -0.122, P < 0.01) masks, indicating that higher education was associated with more CR (i.e. greater atrophy than predicted from cognitive performance). In a voxel-wise analysis, this effect was most prominent in the right inferior and middle temporal and right superior lateral occipital cortex (P < 0.05, corrected for multiple comparisons). Furthermore, survival analyses among subjects in the pre-dementia stage revealed that the W-scores predicted conversion to more advanced disease stages (whole-brain: hazard ratio [HR] = 0.464, P < 0.05; temporoparietal: HR = 0.397, P < 0.001). Our neuroimaging approach captures CR with high anatomical detail and at an individual level. This standardized method is applicable to various brain diseases or CR proxies and can flexibly incorporate different neuroimaging modalities and cognitive parameters, making it a promising tool for scientific and clinical purposes. Hum Brain Mapp 38:4703-4715, 2017. © 2017 Wiley Periodicals, Inc.

Association Between Mentally Stimulating Activities in Late Life and the Outcome of Incident Mild Cognitive Impairment, With an Analysis of the APOE ε4 Genotype

Importance

Cross-sectional associations between engagement in mentally stimulating activities and decreased odds of having mild cognitive impairment (MCI) or Alzheimer disease have been reported. However, little is known about the longitudinal outcome of incident MCI as predicted by late-life (aged ≥70 years) mentally stimulating activities.

Objectives

To test the hypothesis of an association between mentally stimulating activities in late life and the risk of incident MCI and to evaluate the influence of the apolipoprotein E (APOE) ε4 genotype.

Design, Setting, and Participants

This investigation was a prospective, population-based cohort study of participants in the Mayo Clinic Study of Aging in Olmsted County, Minnesota. Participants 70 years or older who were cognitively normal at baseline were followed up to the outcome of incident MCI. The study dates were April 2006 to June 2016.

Main Outcomes and Measures

At baseline, participants provided information about mentally stimulating activities within 1 year before enrollment into the study. Neurocognitive assessment was conducted at baseline, with evaluations at 15-month intervals. Cognitive diagnosis was made by an expert consensus panel based on published criteria. Hazard ratios (HRs) and 95% CIs were calculated using Cox proportional hazards regression models after adjusting for sex, age, and educational level.

Results

The final cohort consisted of 1929 cognitively normal persons (median age at baseline, 77 years [interquartile range, 74-82 years]; 50.4% [n = 973] female) who were followed up to the outcome of incident MCI. During a median follow-up period of 4.0 years, it was observed that playing games (HR, 0.78; 95% CI, 0.65-0.95) and engaging in craft activities (HR, 0.72; 95% CI, 0.57-0.90), computer use (HR, 0.70; 95% CI, 0.57-0.85), and social activities (HR, 0.77; 95% CI, 0.63-0.94) were associated with a decreased risk of incident MCI. In a stratified analysis by APOE ε4 carrier status, the data point toward the lowest risk of incident MCI for APOE ɛ4 noncarriers who engage in mentally stimulating activities (eg, computer use: HR, 0.73; 95% CI, 0.58-0.92) and toward the highest risk of incident MCI for APOE ɛ4 carriers who do not engage in mentally stimulating activities (eg, no computer use: HR, 1.74; 95% CI, 1.33-2.27).

Conclusions and Relevance

Cognitively normal elderly individuals who engage in specific mentally stimulating activities even in late life have a decreased risk of incident MCI. The associations may vary by APOE ε4 carrier status.

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.

Participation in cognitively-stimulating activities is associated with brain structure and cognitive function in preclinical Alzheimer's disease

This study tested the hypothesis that frequent participation in cognitively-stimulating activities, specifically those related to playing games and puzzles, is beneficial to brain health and cognition among middle-aged adults at increased risk for Alzheimer's disease (AD). Three hundred twenty-nine cognitively normal, middle-aged adults (age range, 43.2-73.8 years) enrolled in the Wisconsin Registry for Alzheimer's Prevention (WRAP) participated in this study. They reported their current engagement in cognitive activities using a modified version of the Cognitive Activity Scale (CAS), underwent a structural MRI scan, and completed a comprehensive cognitive battery. FreeSurfer was used to derive gray matter (GM) volumes from AD-related regions of interest (ROIs), and composite measures of episodic memory and executive function were obtained from the cognitive tests. Covariate-adjusted least squares analyses were used to examine the association between the Games item on the CAS (CAS-Games) and both GM volumes and cognitive composites. Higher scores on CAS-Games were associated with greater GM volumes in several ROIs including the hippocampus, posterior cingulate, anterior cingulate, and middle frontal gyrus. Similarly, CAS-Games scores were positively associated with scores on the Immediate Memory, Verbal Learning & Memory, and Speed & Flexibility domains. These findings were not modified by known risk factors for AD. In addition, the Total score on the CAS was not as sensitive as CAS-Games to the examined brain and cognitive measures. For some individuals, participation in cognitive activities pertinent to game playing may help prevent AD by preserving brain structures and cognitive functions vulnerable to AD pathophysiology.

Mechanisms of the Hearing-Cognition Relationship

This review provides a description of age-related changes in hearing and cognition, the relationship between hearing and cognition, and several potential mechanisms that underlie the relationship. Several studies have shown a significant relationship between peripheral hearing loss and cognitive impairment/decline but other studies have not. Furthermore, poor performance on measures of central auditory processing has been significantly associated with cognitive impairment. Important to understanding these relationships are the nature of the underlying mechanisms. Possible mechanisms are overdiagnosis, widespread neural degeneration, sensory degradation/deprivation, cognitive resource allocation/depletion, and social isolation/depression. Overdiagnosis occurs when hearing loss impacts tests of cognitive function or vice versa. Widespread neural degeneration can impact hearing, cognition, or both. Sensory degradation/deprivation due to hearing loss can result in neural degradation and reduced cognitive function. Increased demands due to hearing loss can result in changes in neural resource allocation, reducing available resources for cognitive function. Finally, hearing difficulties can cause social isolation and even depression, increasing the risk for cognitive decline. Data from our laboratory provide support for cognitive resource allocation/depletion. Understanding all five of these mechanisms will advance the development of effective interventions and treatments, thereby enhancing the quality of life of older adults.

Lagged Associations of Metropolitan Statistical Area- and State-Level Income Inequality with Cognitive Function: The Health and Retirement Study

Purpose

Much variation in individual-level cognitive function in late life remains unexplained, with little exploration of area-level/contextual factors to date. Income inequality is a contextual factor that may plausibly influence cognitive function.

Methods

In a nationally-representative cohort of older Americans from the Health and Retirement Study, we examined state- and metropolitan statistical area (MSA)-level income inequality as predictors of individual-level cognitive function measured by the 27-point Telephone Interview for Cognitive Status (TICS-m) scale. We modeled latency periods of 8–20 years, and controlled for state-/metropolitan statistical area (MSA)-level and individual-level factors.

Results

Higher MSA-level income inequality predicted lower cognitive function 16–18 years later. Using a 16-year lag, living in a MSA in the highest income inequality quartile predicted a 0.9-point lower TICS-m score (β = -0.86; 95% CI = -1.41, -0.31), roughly equivalent to the magnitude associated with five years of aging. We observed no associations for state-level income inequality. The findings were robust to sensitivity analyses using propensity score methods.

Conclusions

Among older Americans, MSA-level income inequality appears to influence cognitive function nearly two decades later. Policies reducing income inequality levels within cities may help address the growing burden of declining cognitive function among older populations within the United States.

Selective review of age-related needs of women with schizophrenia

OBJECTIVE

Recognizing that needs differ between men and women with schizophrenia and that they vary over time, this review attempts to categorize the needs that are relevant to younger and to older women.

METHOD

This is a selective literature review focusing on topic areas the two authors determined to be most germane to women with schizophrenia. Articles were selected on the basis of currency, comprehensiveness, and study design. Particular attention was paid to the voices of the women themselves.

RESULTS

There is considerable overlap between the needs of younger and older women with schizophrenia, but as a general rule, younger women require preventive strategies to stop the escalation of illness while older women require recovery interventions to regain lost hopes and abilities.

CONCLUSIONS

There is clinical utility in cataloguing the needs of younger and older women with schizophrenia and conceptualizing interventions according to gender and age rather than viewing needed services along purely diagnostic lines.

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.

Physical and Cognitive Activities as Deterrents of Cognitive Decline in a Biracial Population Sample

OBJECTIVE

Physical and cognitive activities are associated with slower cognitive decline. Few studies have examined racial differences in these associations, however. The aim of this study was to examine the association of physical and cognitive activities with level and change in cognitive function among black and white participants. A secondary aim was to explore observed differences between black and white participants using post hoc analyses based on education and cognitive function levels.

METHODS

Data came from a longitudinal study of 7,742 (63% black and 61% female) participants assessed three times over an average of 9.5 years. At baseline, each participant reported number of hours of leisure time physical activity (categorized using quartiles) and rated frequency of participation in cognitively stimulating activities (range: 0-4). A standardized measure of cognition was derived from tests of memory, perceptual speed, and orientation.

RESULTS

Of the 7,742 participants, 2,322 (30%) reported no physical activity. Cognitive decline was slower by about 20% (95% CI: 13%-27%) among whites with physical activity above 1.25 hours compared with those with no physical activity, but showed no significant decrease in cognitive decline relative to those with no physical activity among blacks. Further post hoc analysis revealed cognitive decline to be slower by about 29% (95% CI: 20%-38%) among blacks and whites with higher education and above average baseline cognition. A 1-point increase in cognitive activity frequency decreased cognitive decline by 8% (95% CI: 3%-14%) among blacks and by 14% (95% CI: 7%-20%) among whites.

CONCLUSIONS

The benefits of higher physical activity on cognitive decline was observed among whites, and among blacks with higher education and above average baseline cognitive function. Nevertheless, the protective effect of cognitive activity seems to be independent of education and baseline cognitive function among both blacks and whites.

The sleep-wake cycle and Alzheimer's disease: what do we know?

Sleep-wake disturbances are a highly prevalent and often disabling feature of Alzheimer's disease (AD). A cardinal feature of AD includes the formation of amyloid plaques, associated with the extracellular accumulation of the amyloid-β (Aβ) peptide. Evidence from animal and human studies suggests that Aβ pathology may disrupt the sleep-wake cycle, in that as Aβ accumulates, more sleep-wake fragmentation develops. Furthermore, recent research in animal and human studies suggests that the sleep-wake cycle itself may influence Alzheimer's disease onset and progression. Chronic sleep deprivation increases amyloid plaque deposition, and sleep extension results in fewer plaques in experimental models. In this review geared towards the practicing clinician, we discuss possible mechanisms underlying the reciprocal relationship between the sleep-wake cycle and AD pathology and behavior, and present current approaches to therapy for sleep disorders in AD.

Modeling cognitive reserve in healthy middle-aged and older adults: the Tasmanian Healthy Brain Project

BACKGROUND

Cognitive reserve (CR) is a protective factor that supports cognition by increasing the resilience of an individual's cognitive function to the deleterious effects of cerebral lesions. A single environmental proxy indicator is often used to estimate CR (e.g. education), possibly resulting in a loss of the accuracy and predictive power of the investigation. Furthermore, while estimates of an individual's prior CR can be made, no operational measure exists to estimate dynamic change in CR resulting from exposure to new life experiences.

METHODS

We aimed to develop two latent measures of CR through factor analysis: prior and current, in a sample of 467 healthy older adults.

RESULTS

The prior CR measure combined proxy measures traditionally associated with CR, while the current CR measure combined variables that had the potential to reflect dynamic change in CR due to new life experiences. Our main finding was that the analyses uncovered latent variables in hypothesized prior and current models of CR.

CONCLUSIONS

The prior CR model supports multivariate estimation of pre-existing CR and may be applied to more accurately estimate CR in the absence of neuropathological data. The current CR model may be applied to evaluate and explore the potential benefits of CR-based interventions prior to dementia onset.

Increases in lifestyle activities as a result of experience Corps® participation

Experience Corps® (EC) was designed to simultaneously increase cognitive, social, and physical activity through high-intensity volunteerism in elementary school classrooms. It is, therefore, highly likely that EC participation may alter pre-existing patterns of lifestyle activity. This study examined the impact of "real-world" volunteer engagement on the frequency of participation in various lifestyle activities over a 2-year period. Specifically, we examined intervention-related changes on reported activity levels at 12 and 24 months post-baseline using Intention-to-Treat (ITT) and Complier Average Causal Effect (CACE) analyses, which account for the amount of program exposure. ITT analyses indicated that, compared to the control group, EC participants reported modest increases (approximately half a day/month) in overall activity level, especially in intellectual and physical activities 12 months post-baseline. Increases in activity were not found at the 24-month assessment. CACE models revealed similar findings for overall activity as well as for intellectual and physical activities at 12 months. Additionally, CACE findings suggested modest increases in social activity at 12 months and in intellectual and passive activities at 24 months post-baseline. This community-based, health promotion intervention has the potential to impact lifestyle activity, which may lead to long-term increases in activity and to other positive cognitive, physical, and psychosocial health outcomes.

The evolution of preclinical Alzheimer's disease: implications for prevention trials

As the field begins to test the concept of a "preclinical" stage of neurodegenerative disease, when the pathophysiological process has begun in the brain, but clinical symptoms are not yet manifest, a number of intriguing questions have already arisen. In particular, in preclinical Alzheimer's disease (AD), the temporal relationship of amyloid markers to markers of neurodegeneration and their relative utility in the prediction of cognitive decline among clinically normal older individuals remains to be fully elucidated. Secondary prevention trials in AD have already begun in both genetic at-risk and amyloid at-risk cohorts, with several more trials in the planning stages, and should provide critical answers about whether intervention at this very early stage of disease can truly bend the curve of clinical progression. This review will highlight recent progress in cognitive, imaging, and biomarker outcomes in the field of preclinical AD, and the remaining gaps in knowledge.

Quality of Life in an Adult Population of More than 60 Years of Age without Cognitive Impairment

Objectives

To analyse the quality of life (QoL) of persons over 60 years of age in Bizkaia (Basque Country, Spain), not institutionalised and without cognitive impairment, and the relation and possible influence of the perception of the state of health with the cognitive level and the activities that they carry out.

Subjects and Methods

Evaluation of a sample of 317 persons that belong to a longitudinal study. In 269 cases, there was a reliable informant. The general cognitive state was evaluated by means of the Mini-Mental State Examination (MMSE) and the Global Deterioration Scale (GDS). Two GDS, one of the family member (GDSf) and another of the evaluator (GDSe), were used and memory was evaluated by the Text Memory subtest of the Barcelona Test. The QoL was assessed with the SF-36 Health Survey and the mental, physical and social activities that they carry out were recorded.

Results

In the SF-36, the participants showed values that exceed the reference values of the Spanish population in all dimensions of the SF-36, except in that of bodily pain. There were low correlations between the dimensions of the SF-36 and the mental, physical and social activities. A low correlation was observed between the memory tests and the SF-36. In 59.3% of the cases, there were no differences between the GDSf and the GDSe.

Conclusions

The participants of this study present a better perception of their state of health than the Spanish population, but this perception is not observed to be influenced by the type or by the quantity of activities that they carry out or by their cognitive state. The informants present a vision very close to the cognitive state of their family members.

Marital Status and Cognitive Impairment among Community-Dwelling Chinese Older Adults: The Role of Gender and Social Engagement

Aims

To examine the association between marital status and cognitive impairment among community-dwelling Chinese older adults.

Methods

We analyzed data from 2,498 Chinese aged 55 and older from the Singapore Longitudinal Aging Study cohort. Cognitive impairment was defined as a Mini-Mental State Examination total score of 23 or below. Odds ratios of associations were reported and adjusted for potential confounders in logistic regression models.

Results

The prevalence of cognitive impairment was 12.2% (n = 306). Being single was associated with about 2.5 times increased odds of cognitive impairment compared to being married (adjusted OR = 2.53, 95% CI: 1.41-4.55). The association between marital status and cognitive impairment was much stronger in men compared to that in women, and was indeed statistically significant only for men. Among the single and widowed persons social engagement was associated with a lower risk of cognitive impairment. Compared with subjects in the lowest tertile of social engagement scores, the odds of having cognitive impairment was lowered by 50% for subjects in the second and the third tertile.

Conclusion

Being single or widowed was associated with higher odds of cognitive impairment compared to being married in a cohort of older Chinese men but not women.