Relation of cognitive activity to risk of developing Alzheimer disease

Strengthening older adults remembering (SOARing): Research protocol for a multi-site randomized clinical trial examining the efficacy of the Kessler Foundation modified story memory technique (KF-mSMT®) in mild cognitive impairment (MCI)

BACKGROUND

Long-term memory dysfunction is the hallmark feature of amnestic mild cognitive impairment (aMCI) resulting in substantial negative impact on everyday functioning and quality of life. The Kessler Foundation modified Story Memory Technique (KF-mSMT®) is a 10-session memory rehabilitation protocol in which participants are taught to utilize imagery and context to facilitate learning. This paper describes the protocol for a double blind, placebo controlled, randomized clinical trial (RCT) examining the efficacy of the KF-mSMT® in persons who meet criteria for aMCI.

METHODS

Participants will undergo baseline assessments consisting of neuropsychological testing, neuroimaging, self-report questionnaires, and a blood draw for measuring plasma biomarkers. Participants will then be randomized to one of two conditions using concealed allocation: KF-mSMT® or an active placebo control condition consisting of memory exercises. Participants will be blinded to condition. Within 2 weeks of completing the intervention, participants will complete the same measures as at baseline administered by treatment-blinded assessors. The primary study outcome is new learning and memory measured by neuropsychological assessment (Open Trial Selective Reminding Test). Secondary outcomes include other measures of learning and memory (i.e. Repeatable Battery for the Assessment of Neuropsychological Status story), visuospatial memory (Brief Visuospatial Memory Test-Revised)) as well as everyday memory (Ecological Memory Simulations, Object Location Touchscreen Test), neuroimaging and plasma biomarkers.

CONCLUSION

If successful, this trial will provide Class I evidence supporting the application of the KF-mSMT® for treating MCI-related learning and memory decline in older adults.

Early-life cognitively stimulating activities and late-life cognitive function in the St. Louis Baby Tooth Later Life Health Study

Childhood cognitively stimulating activities have been associated with higher cognitive function in late life. Whether activities in early or late childhood are more salient, and whether activities are associated with specific cognitive domains is unknown. Participants retrospectively reported cognitively stimulating activities at ages 6, 12, and 18 years. 4,198 participants were aged 55 to 77 years at cognitive testing. Six tasks measured overall cognitive function, processing speed, visual short-term memory, attention, cognitive control, episodic memory, working memory, perception, vocabulary, and verbal reasoning. Cognitively stimulating activities across childhood were associated with higher cognitive scores (highest versus lowest quartile, beta = 0.18 SD, 95% CI = 0.12, 0.23). In models adjusted for activities at each age, only age 18 activities were associated with overall cognition. The association of activities with cognitive function was strongly positive at the lowest levels of activities, with little association at middle and high levels of activities. A test of crystalized intelligence was most strongly associated with activities; tests assessing processing speed, visual short-term memory, visual working memory, and sustained attention were least associated. If the associations we found are causal, increasing cognitively stimulating activities in the late teen years among those with very few activities may benefit late life cognitive health.

Cognitive reserve and its impact on cognitive and functional abilities, physical activity and quality of life following a diagnosis of dementia: longitudinal findings from the Improving the experience of Dementia and Enhancing Active Life (IDEAL) study

BACKGROUND

The concept of cognitive reserve may explain inter-individual differences in susceptibility to neuropathological changes. Studies suggest that experiences over a lifetime impact on cognitive reserve, and it is hypothesised that following a dementia diagnosis, greater reserve levels are linked to accelerated disease progression.

OBJECTIVE

To investigate the longitudinal impact of cognitive reserve on cognitive and functional abilities, physical activity and quality of life in people with dementia.

DESIGN

Longitudinal cohort design.

SETTING AND PARTICIPANTS

Participants were 1537 people with mild-to-moderate dementia at baseline, 1183 at 12 months follow-up and 851 at 24 months follow-up, from the IDEAL study.

METHODS

A comprehensive latent measure of cognitive reserve incorporated domains from all stages of life: education, occupational attainment and later-life engagement in leisure activities. The impact of cognitive reserve on cognition, functional abilities, physical activity and quality of life at baseline and over time was investigated using latent growth curve modelling.

RESULTS

Higher cognitive reserve was associated with better cognition, fewer functional difficulties, more physical activity and better quality of life at baseline but was associated with accelerated cognitive decline and greater dependence over time. After 2 years, those with higher initial reserve were estimated to still have better cognition than those with low reserve.

CONCLUSIONS

Cognitive reserve may be important in initially delaying dementia progression but is linked with accelerated deterioration once dementia becomes clinically evident, likely because of the more advanced neuropathological stage of the condition. Engagement in leisure activities is a potentially modifiable domain of cognitive reserve warranting further investigation.

The Relationship Between Subjective Cognitive Decline and Cognitive Leisure Activity Engagement: A Systematic Review

BACKGROUND AND OBJECTIVES

Subjective cognitive decline (SCD) is a common experience of self-perceived decline without objective cognitive impairment. It has been theorized that SCD is associated with participation in cognitive leisure activities (CLAs), but the evidence base is multifarious and unclear. The purpose of this systematic review was to synthesize current evidence to determine the association between SCD and CLA engagement.

RESEARCH DESIGN AND METHODS

Systematic searches were conducted in EMBASE, MEDLINE, PsycINFO, and Web of Science (last searched April 2023). Data were extracted against a priori inclusion criteria and synthesized narratively using Synthesis without Meta-Analysis guidelines. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) and Mixed Methods Appraisal Tool (MMAT). Reporting follows PRISMA guidelines.

RESULTS

From 4,447 records, 11 articles were included. Due to study heterogeneity, evidence on SCD and CLA association is inconclusive. Although a modest correlation was found between greater engagement in CLA and fewer reports of SCD, the heterogeneity in study designs and outcomes, particularly in those addressing only perceived memory decline and CLA engagement, challenges definitive conclusions on this relationship. Evidence from mixed-method and qualitative studies indicated that perceived memory decline may cause negative feelings, such as shame and frustration, which may influence participating in CLA.

DISCUSSION AND IMPLICATIONS

These findings suggest that participation in CLA is moderately associated with, and may act protectively against, SCD. However, establishing a directional or causal relationship between CLA participation and SCD outcomes requires further investigation through longitudinal and/or interventional studies.

External validation of dementia prediction models in Black or African American and White older adults: A longitudinal population-based study in the United States

INTRODUCTION

Identifying people at high risk of Alzheimer's disease (AD) dementia allows for timely intervention, which, if successful, will result in preventing or delaying the onset of the disease.

METHODS

Utilizing data from the Chicago Health and Aging Project (CHAP; n = 2130), we externally evaluated four risk-prediction models for AD dementia, including Cardiovascular Risk Factors, Aging, and Dementia (CAIDE), Australian National University Alzheimer's Disease Risk Index (ANU-ADRI), Brief Dementia Screening Indicator (BDSI), and Dementia Risk Score (DRS), in Black or African American and White adults.

RESULTS

BDSI had the highest discriminate abilities for AD dementia (c-statistics of 0.79 in Black and 0.77 in White adults), followed by ANU-ADRI, within the age range and follow-up period of the original development cohort. CAIDE had the lowest discriminating power (c-statistic ≤0.55). With increasing follow-up periods (i.e., 10-15 years), the discrimination abilities for all models declined.

DISCUSSION

Because of racial disparities in AD dementia and longer preclinical and prodromal stages of disease development, race-specific models are needed to predict AD risk over 10 years.

HIGHLIGHTS

Utilizing risk-prediction models to identify individuals at higher risk of Alzheimer's disease (AD) dementia could benefit clinicians, patients, and policymakers. Clinicians could enroll high-risk individuals in clinical trials to test new risk-modifiable treatments or initiate lifestyle modifications, which, if successful, would slow cognitive decline and delay the onset of the disease. Current risk-prediction models had good discriminative power during the first 6 years of follow-up but decreased with longer follow-up time. Acknowledging the longer preclinical phase of AD dementia development and racial differences in dementia risk, there is a need to develop race-specific risk-prediction models that can predict 10 or 20 years of risk for AD and related dementias.

Brain Iron in signature regions relating to cognitive aging in older adults: the Taizhou Imaging Study

BACKGROUND

Recent magnetic resonance imaging (MRI) studies have established that brain iron accumulation might accelerate cognitive decline in Alzheimer's disease (AD) patients. Both normal aging and AD are associated with cerebral atrophy in specific regions. However, no studies have investigated aging- and AD-selective iron deposition-related cognitive changes during normal aging. Here, we applied quantitative susceptibility mapping (QSM) to detect iron levels in cortical signature regions and assessed the relationships among iron, atrophy, and cognitive changes in older adults.

METHODS

In this Taizhou Imaging Study, 770 older adults (mean age 62.0 ± 4.93 years, 57.5% women) underwent brain MRI to measure brain iron and atrophy, of whom 219 underwent neuropsychological tests nearly every 12 months for up to a mean follow-up of 2.68 years. Global cognition was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Domain-specific cognitive scores were obtained from MoCA subscore components. Regional analyses were performed for cortical regions and 2 signature regions where atrophy affected by aging and AD only: Aging (AG) -specific and AD signature meta-ROIs. The QSM and cortical morphometry means of the above ROIs were also computed.

RESULTS

Significant associations were found between QSM levels and cognitive scores. In particular, after adjusting for cortical thickness of regions of interest (ROIs), participants in the upper tertile of the cortical and AG-specific signature QSM exhibited worse ZMMSE than did those in the lower tertile [β = -0.104, p = 0.026;β = -0.118, p = 0.021, respectively]. Longitudinal analysis suggested that QSM values in all ROIs might predict decline in ZMoCA and key domains such as attention and visuospatial function (all p < 0.05). Furthermore, iron levels were negatively correlated with classic MRI markers of cortical atrophy (cortical thickness, gray matter volume, and local gyrification index) in total, AG-specific signature and AD signature regions (all p < 0.05).

CONCLUSION

AG- and AD-selective iron deposition was associated with atrophy and cognitive decline in elderly people, highlighting its potential as a neuroimaging marker for cognitive aging.

Causal relationships between dyslexia and the risk of eight dementias

Observational and genetic studies have reported the relationship between dyslexia and Alzheimer's disease (AD). Until now, the causal effect of dyslexia on AD risk has remained unclear. We conducted a two-sample univariable Mendelian randomization (MR) analysis to determine the causal association between dyslexia and the risk of AD, vascular dementia (VD), Lewy body dementia (LBD), and frontotemporal dementia (FTD) and its four subtypes. First, we selected 42 dyslexia genetic variants from a large-scale genome-wide association studies (GWAS) dataset and extracted their corresponding GWAS summary statistics from AD, VD, LBD, and FTD. Second, we selected four MR methods, including inverse-variance weighted (IVW), weighted median, MR-Egger, and MR-PRESSO. Heterogeneity, horizontal pleiotropy, and leave-one-out sensitivity analysis were then used to evaluate the reliability of all causal estimates. We also conducted multivariable MR (MVMR) and mediation analysis to assess the potential mediating role of cognitive performance (CP) or educational achievement (EA) on the causal association between dyslexia and AD. Two MVMR methods, including MV IVW and MV-Egger, and two-step MR were used to perform the analysis. Using IVW, we found a significant causal association between increased dyslexia and increased risk of AD (OR = 1.15, 95% CI: 1.04-1.28, P = 0.006), but not VD, LBD, FTD, or its four subtypes. MR-PRESSO further supported the statistically significant association between dyslexia and AD (OR = 1.15, 95% CI: 1.05-1.27, P = 0.006). All sensitivity analyses confirmed the reliability of causal estimates. Using MV IVW and mediation analysis, we found no causal relationship between dyslexia and AD after adjusting for CP but not EA, CP mediated the total effect of dyslexia on AD with a proportion of 46.32%. We provide genetic evidence to support a causal effect of increased dyslexia on increased risk of AD, which was largely mediated by CP. Reading activity may be a potential intervention strategy for AD by improving cognitive function.

Cross-cultural adaptation and validation of the Australian National University Alzheimer Disease Risk Index (ANU-ADRI) for Chinese community-dwelling residents: A cross-sectional Study

OBJECTIVE

To cross-culturally adapt the Australian National University Alzheimer Disease Risk Index (ANU-ADRI) and verify the reliability and validity of its cognitive activity domain.

METHODS

According to Beaton's guidelines, the ANU-ADRI was were translated into Chinese. The psychometric properties of ANU-ADRI its cognitive activity was conducted among community-dwelling residents (n = 442) in Changchun, Harbin and Hegang from December 2021 to July 2023.

RESULTS

The Chinese version of the ANU-ADRI had good content validity and face validity. Exploratory factor analysis of cognitive activity revealed a 3-factor structure, with a cumulative variance contribution rate of 64.124 %. Confirmatory factor analysis revealed a good model fit (x2/df = 1.664, RMSEA = 0.055, RMR = 0.090, GFI = 0.942, CFI = 0.919, IFI = 0.921, TLI = 0.902, and NFI = 0.824). The internal consistency (Cronbach's α = 0.807) and test-retest reliability (ICC = 0.787) were considered satisfactory.

CONCLUSION

The ANU-ADRI showed acceptable reliability and validity for assessing risk factors for Alzheimer's disease among middle-aged and elderly community-dwelling residents.

Childhood engagement in cognitively stimulating activities moderates relationships between brain structure and cognitive function in adulthood

Greater engagement in cognitively stimulating activities (CSA) during adulthood has been shown to protect against neurocognitive decline, but no studies have investigated whether CSA during childhood protects against effects of brain changes on cognition later in life. The current study tested the moderating role of childhood CSA in the relationships between brain structure and cognitive performance during adulthood. At baseline (N=250) and 5-year follow-up (N=204) healthy adults aged 20-80 underwent MRI to assess four structural brain measures and completed neuropsychological tests to measure three cognitive domains. Participants were categorized into low and high childhood CSA based on self-report questionnaires. Results of multivariable linear regressions analyzing interactions between CSA, brain structure, and cognition showed that higher childhood CSA was associated with a weaker relationship between cortical thickness and memory at baseline, and attenuated the effects of change in cortical thickness and brain volume on decline in processing speed over time. These findings suggest higher CSA during childhood may mitigate the effects of brain structure changes on cognitive function later in life.

The concept of resilience to Alzheimer's Disease: current definitions and cellular and molecular mechanisms

Some individuals are able to maintain their cognitive abilities despite the presence of significant Alzheimer's Disease (AD) neuropathological changes. This discrepancy between cognition and pathology has been labeled as resilience and has evolved into a widely debated concept. External factors such as cognitive stimulation are associated with resilience to AD, but the exact cellular and molecular underpinnings are not completely understood. In this review, we discuss the current definitions used in the field, highlight the translational approaches used to investigate resilience to AD and summarize the underlying cellular and molecular substrates of resilience that have been derived from human and animal studies, which have received more and more attention in the last few years. From these studies the picture emerges that resilient individuals are different from AD patients in terms of specific pathological species and their cellular reaction to AD pathology, which possibly helps to maintain cognition up to a certain tipping point. Studying these rare resilient individuals can be of great importance as it could pave the way to novel therapeutic avenues for AD.

Cognitive reserve predicts episodic memory enhancement induced by transcranial direct current stimulation in healthy older adults

Episodic memory shows the largest degree of age-related decline. Anodal transcranial Direct Current Stimulation (tDCS) can enhance episodic memory in aging but there is also evidence of response variability even when using identical stimulation parameters. To explore which inter-individual factors (i.e. age, education, encoding performance, cognitive reserve, tDCS group and timing of tDCS application) may directly and/or indirectly modulate verbal memory recall, we used data from our previous tDCS studies that showed enhanced episodic memory recall in 80 healthy older adults. In these studies we used the same paradigm and stimulation parameters but tDCS was applied during different memory stages. Memory recall was tested 48 hours and 30 days after encoding. Univariate regression models showed that tDCS group (Anodal vs. Sham) predicted memory recall, indicating higher scores in the Anodal group than in the Sham group. Encoding performance predicted memory recall in both tDCS groups. Multiple regression models revealed that cognitive reserve, measured with a life experience questionnaire, predicted memory recall only for the Anodal group. Higher cognitive reserve was linked to better memory recall. Accounting for individual differences in cognitive reserve at baseline helps to explain tDCS responsiveness. This knowledge may contribute to optimize its use in older adults.

A change in social participation affects cognitive function in middle-aged and older Chinese adults: analysis of a Chinese longitudinal study on aging (2011-2018)

Background

One of the biggest challenges facing older adults is cognitive decline and social participation has always been considered a protective factor. However, it is not clear whether social participation predicts cognitive function in this population, rather than depressive symptoms, self-reported health, and activities of daily life, with sufficient capacity to detect unique effects.

Methods

This study included adults aged 45 and above in China (N = 5,258) who participated in a large national older adult health survey and provided data from 2011, 2013, 2015, and 2018. The unique associations between the predictors of social participation and cognitive function over time and context were evaluated in the Latent Growth Model (LGM).

Results

Among the 5,258 participants in our study, an overall cognitive decline was observed. Social participation predicts two dimensions of cognitive function, with a degree of impact comparable to depressive symptoms, self-reported health, and activities of daily life. Among them, social participation exhibits a noteworthy prognostic impact on episodic memory during the same period. The regression coefficient is approximately 0.1 (p < 0.05) after controlling other mixed variables (depressive symptoms, self-reported health, and activities of daily life). In contrast, social participation is also a significant predictor of mental intactness in the same period, with a regression coefficient of 0.06 (p < 0.05), even if all mixed variables are controlled.

Conclusion

Over time, the correlation strength of social participation is comparable to other recognized cognitive function prediction indicators, indicating that promoting social participation among middle-aged and older Chinese adults is a meaningful way to improve cognitive function degradation, which has important policy and practical significance.

Memory support training and lifestyle modifications to promote healthy aging in persons at risk for Alzheimer's disease: a digital application supported intervention (Brain Boosters)

BACKGROUND

Evidence-based interventions to protect against cognitive decline among older adults at risk for Alzheimer's disease and related dementias (ADRD) are urgently needed. Rehabilitation approaches to support memory and behavioral/lifestyle interventions are recognized as promising strategies for preserving or improving cognitive health, although few previous interventions have combined both approaches. This paper describes the protocol of the Brain Boosters intervention, which synergistically combines training in compensatory and healthy lifestyle behaviors and supports implementation and tracking of new behaviors with a digital application.

METHODS

The study utilizes a single-site, single-blinded, randomized controlled design to compare a structured lifestyle and compensatory aid intervention to an education-only self-guided intervention. We plan to enroll 225 community-dwelling adults (25% from underrepresented groups) aged 65 + who endorse subjective cognitive decline (SCD) and low baseline levels of healthy lifestyle behaviors. Both interventions will be administered in group format, consisting of 15 two-hour classes that occur weekly for ten weeks and taper to bi-monthly and monthly, for an intervention duration of 6 months. Participants in both interventions will receive education about a variety of memory support strategies and healthy lifestyle behaviors, focusing on physical and cognitive activity and stress management. The structured intervention will also receive support in adopting new behaviors and tracking set goals aided by the Electronic Memory and Management Aid (EMMA) digital application. Primary outcomes include global cognition (composite of memory, attention, and executive function tests) and everyday function (Everyday Cognition Questionnaire). Data will be collected at baseline and outcome visits, at approximately 6, 12, and 18 months. Qualitative interviews, self-report surveys (e.g., indicators of self-determination, health literacy) and EMMA data metrics will also be used to identify what components of the intervention are most effective and for whom they work.

DISCUSSION

Successful project completion will provide valuable information about how individuals with SCD respond to a compensation and preventative lifestyle intervention assisted by a digital application, including an understanding of factors that may impact outcomes, treatment uptake, and adherence. The work will also inform development, scaling, and personalization of future interventions that can delay disability in individuals at risk for ADRD.

TRIAL REGISTRATION

ClinicalTrials.gov. (NCT05027789, posted 8/30/2021).

Internal consistency and reliability of the lifetime and modified current cognitive activity questionnaires and their association with cognitive performance: a six-year follow up of the Brain in Motion study

INTRODUCTION

Cognitive activity questionnaires could provide insight into neurocognitive reserve. The Lifetime Cognitive Activities Questionnaire (LCAQ) assesses cognitive activities at four stages of life. The Modified Current Cognitive Activities Questionnaire (CCAQ) assesses current cognitive activities. We examined the construct validity, internal consistency, test-retest reliability, and stability of these questionnaires throughout the Brain in Motion (BIM) study and their relationship with cognitive performance.

METHODS

The LCAQ, Montreal Cognitive Assessment (MoCA), and neuropsychological battery were administered at the initial pre-intervention and six-year follow-up. The CCAQ was administered at five timepoints. Construct validity of the CCAQ/LCAQ was assessed using proxies of cognitive engagement (educational attainment and the North American Adult Reading Test [NAART]). Cronbach alpha analysis determined internal consistency. LCAQ reliability was established by comparing the pre-intervention and six-year follow-up. CCAQ reliability was determined by comparing both pre-intervention assessments, correlations throughout BIM determined stability. A multiple linear regression investigated the associations between cognitive engagement and cognitive domains derived from a principal component analysis.

RESULTS

MoCA scores at the initial pre-intervention (27.49 ± 1.46) and six-year follow up (26.53 ± 2.08). The LCAQ and CCAQ correlated with educational attainment and the NAART. The LCAQ (n = 266) produced an alpha of 0.90 (20 items). The CCAQ (n = 261) resulted in an alpha of 0.71 (25 items). LCAQ scores (n = 94) at the initial pre-intervention and six-year follow-up were correlated. CCAQ (n = 94) scores at the initial pre-intervention correlated with scores at all five other timepoints. The multiple linear regression revealed associations between the CCAQ and verbal memory/attention. The NAART was associated with processing speed, concept formation, and verbal memory/attention.

CONCLUSIONS

In the absence of cognitive decline, these questionnaires exhibit significant construct validity, internal consistency, test-retest reliability, and the CCAQ displayed stability. The NAART and CCAQ were associated with neuropsychological performance. Our findings support future use of these questionnaires and exemplify the neuroprotective role of cognitive engagement.

Associations between social health factors, cognitive activity and neurostructural markers for brain health - A systematic literature review and meta-analysis

Social health factors (e.g., social activities or social support) and cognitive activity engagement have been associated with dementia risk, but their neural substrates have not been well established. This systematic review and meta-analysis summarizes the available evidence regarding the association between these factors and cerebral macro- and micro-structure. A comprehensive literature search was conducted in various databases, following predefined criteria. Heterogeneity, risk of publication bias and overall certainty of evidence were assessed using standardized scales and, whenever appropriate, random effects meta-analysis was conducted. Of 6715 identified articles, 43 were included. Overall, consistency of findings was low and methodological heterogeneity high for all outcomes. However, in some studies cognitive and social activities were positively associated with total brain, global and cortical grey matter and hippocampal volume as well as white matter microstructural integrity. Furthermore, structural social network characteristics (e.g., social network size) were associated with regional grey matter volumes, while functional social network characteristics (e.g., social support) were additionally associated with total brain volume. Meta-analyses revealed small but significant partial correlations between cognitive and social activities and hippocampal (three studies; n = 892; rz =0.07) and white matter hyperintensity volume (three studies; n = 2934; rz =-0.04). More prospective studies are needed to assess temporal associations.

Direct Effect of Life-Course Socioeconomic Status on Late-Life Cognition and Cognitive Decline in the Rush Memory and Aging Project

The role of socioeconomic status (SES) across the life course in late-life cognition is unclear. We tested the hypotheses that: 1) High SES in childhood, young adulthood, midlife, and late life have independent causal effects on higher cognition level and slower cognitive decline; 2) Compared with stable low SES (referent), stable high SES has the largest estimated effect for higher cognition level and slower decline among life-course SES combinations. The Rush Memory and Aging Project enrolled 1,940 dementia-free older adults in northeastern Illinois (1997-2018). We used inverse probability-weighted marginal structural models to estimate the joint and independent effect of each life-course SES on global and domain-specific cognition. A total of 1,746 participants had, on average, 6 years of follow-up. High SES at each life-course stage starting in young adulthood had a protective estimated effect on global and domain-specific cognition intercepts. Compared with consistently low SES, consistently high SES (β = 0.64, 95% confidence interval: 0.48, 0.93) and high SES beyond childhood (β = 0.64, 95% confidence interval: 0.47, 0.83) had the largest benefit for global cognition intercepts. None of the life-course SES measures influenced rate of global or domain-specific decline. Additional understanding of life-course SES components influencing cognitive level is warranted.

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.

Brain-Derived Neurotrophic Factor (BDNF) in Mechanisms of Autistic-like Behavior in BTBR Mice: Crosstalk with the Dopaminergic Brain System

Disturbances in neuroplasticity undoubtedly play an important role in the development of autism spectrum disorders (ASDs). Brain neurotransmitters and brain-derived neurotrophic factor (BDNF) are known as crucial players in cerebral and behavioral plasticity. Such an important neurotransmitter as dopamine (DA) is involved in the behavioral inflexibility of ASD. Additionally, much evidence from human and animal studies implicates BDNF in ASD pathogenesis. Nonetheless, crosstalk between BDNF and the DA system has not been studied in the context of an autistic-like phenotype. For this reason, the aim of our study was to compare the effects of either the acute intracerebroventricular administration of a recombinant BDNF protein or hippocampal adeno-associated-virus-mediated BDNF overexpression on autistic-like behavior and expression of key DA-related and BDNF-related genes in BTBR mice (a widely recognized model of autism). The BDNF administration failed to affect autistic-like behavior but downregulated Comt mRNA in the frontal cortex and hippocampus; however, COMT protein downregulation in the hippocampus and upregulation in the striatum were insignificant. BDNF administration also reduced the receptor TrkB level in the frontal cortex and midbrain and the BDNF/proBDNF ratio in the striatum. In contrast, hippocampal BDNF overexpression significantly diminished stereotypical behavior and anxiety; these alterations were accompanied only by higher hippocampal DA receptor D1 mRNA levels. The results indicate an important role of BDNF in mechanisms underlying anxiety and repetitive behavior in ASDs and implicates BDNF-DA crosstalk in the autistic-like phenotype of BTBR mice.

Resting-state MRI functional connectivity as a neural correlate of multidomain lifestyle adherence in older adults at risk for Alzheimer's disease

Prior research has demonstrated the importance of a healthy lifestyle to protect brain health and diminish dementia risk in later life. While a multidomain lifestyle provides an ecological perspective to voluntary engagement, its association with brain health is still under-investigated. Therefore, understanding the neural mechanisms underlying multidomain lifestyle engagement, particularly in older adults at risk for Alzheimer's disease (AD), gives valuable insights into providing lifestyle advice and intervention for those in need. The current study included 139 healthy older adults with familial risk for AD from the Prevent-AD longitudinal aging cohort. Self-reported exercise engagement, cognitive activity engagement, healthy diet adherence, and social activity engagement were included to examine potential phenotypes of an individual's lifestyle adherence. Two adherence profiles were discovered using data-driven clustering methodology [i.e., Adherence to healthy lifestyle (AL) group and Non-adherence to healthy lifestyle group]. Resting-state functional connectivity matrices and grey matter brain features obtained from magnetic resonance imaging were used to classify the two groups using a support vector machine (SVM). The SVM classifier was 75% accurate in separating groups. The features that show consistently high importance to the classification model were functional connectivity mainly between nodes located in different prior-defined functional networks. Most nodes were located in the default mode network, dorsal attention network, and visual network. Our results provide preliminary evidence of neurobiological characteristics underlying multidomain healthy lifestyle choices.

Stability and change in acculturation-related characteristics in older Latinos: Implications for culturally compatible ADRD research

Introduction

Acculturation-related characteristics, that is, factors directly connected to culture and familial relationships, are associated with engaged research participation within Latino communities. Despite this, little empirical data exists on whether acculturation changes over time in older Latinos, which has potential implications for Alzheimer's disease and related dementias (ADRD) research study design including longer duration clinical trial implementation.

Methods

Self-identified Latinos (n = 222; mean age = 71, 76% female) participating in one of three ongoing longitudinal community-based cohort studies of aging who reported their nativity outside of the United States/District of Columbia (US/DC) contributed, on average, 4.0 ± 1.2 years of annually collected data. This included acculturation-related characteristics of total, language-, and social-based scores from the Short Acculturation Scale for Hispanics (SASH) and total and domain-specific scores from an abbreviated Sabogal Familism questionnaire. We used ordinal mixed effects models and linear mixed effects models (as appropriate) to assess change in acculturation metrics after adjusting for age, sex, education, income, and duration of time in the US/DC.

Results

Although none of the SASH metrics changed over time (P-values ≥ 0.25), all Familism metrics declined over time (P-values ≤ 0.044). Additionally, select participant-based characteristics including years of education were significantly (and differentially) associated with level of, but not change in, acculturation-related outcomes.

Discussion

Results suggest that specific acculturation-related factors (i.e., familism) change over time in older Latinos, and participant-based characteristics associated with baseline levels of (but not change in) acculturation more generally. Thus, acculturation-related characteristics are not all static, trait-like qualities but rather a multi-faceted, and at times evolving, construct. Considering this dynamic phenotyping is important when contextualizing older Latinos' lived experience, and when designing, adapting, and conducting ADRD clinical trials and other health-related interventions.

Cognitive Effort-Based Decision-Making Across Experimental and Daily Life Indices in Younger and Older Adults

OBJECTIVES

The study investigated whether cognitive effort decision-making measured via a neuroeconomic paradigm that manipulated framing (gain vs. loss outcomes), could predict daily life engagement in mentally demanding activities in both younger and older adults.

METHOD

Younger and older adult participants (N = 310) completed the Cognitive Effort Discounting paradigm (Cog-ED), under both gain and loss conditions, to provide an experimental index of cognitive effort costs for each participant in each framing condition. A subset of participants (N = 230) also completed a 7-day Ecological Momentary Assessment (EMA) protocol measuring engagement in mentally demanding daily life activities.

RESULTS

In a large, online sample, we replicated a robust increase in cognitive effort costs among older, relative to younger, adults. Additionally, costs were found to be reduced in the loss relative to gain frame, although these effects were only reliable at high levels of task difficulty and were not moderated by age. Critically, participants who had lower effort costs in the gain frame tended to report engaging in more mentally demanding daily life activities, but the opposite pattern was observed in the loss frame. Further analyses demonstrated the specificity of reward-related cognitive motivation in predicting daily life mentally demanding activities.

DISCUSSION

Together, these results suggest that cognitive effort costs, as measured through behavioral choice patterns in a neuroeconomic decision-making task, can be used to predict and explain engagement in mentally demanding activities during daily life among both older and younger adults.

Mind-stimulating leisure activities: Prospective associations with health, wellbeing, and longevity

Introduction

This study examines prospective associations within a 6-year perspective between three mind-stimulating leisure activities (relaxed and solitary: reading; serious and solitary: doing number and word games; serious and social: playing cards and games) and 21 outcomes in (1) physical health, (2) wellbeing, (3) daily life functioning, (4) cognitive impairment, and (5) longevity domains.

Methods

Data were obtained from 19,821 middle-aged and older adults from 15 countries participating in the Survey of Health, Ageing, and Retirement in Europe (SHARE). Temporal associations were obtained using generalized estimating equations. All models were controlled for prior sociodemographic, personality, lifestyle factors, health behaviors, and pre-baseline leisure activity values and all outcome variables. The Bonferroni correction was used to correct for multiple testing. E-values were calculated to examine the sensitivity of the associations to unmeasured confounding. Secondary analyses (1) under the complete case scenario, (2) after excluding respondents with health conditions, and (3) using a limited set of covariates were conducted to provide evidence for the robustness of the results.

Results

The relaxed solitary activity of reading almost daily was prospectively associated with a lower risk of depression, experiencing pain, daily functioning limitations, cognitive impairment, lower loneliness scores, and more favorable wellbeing outcomes. Engaging in serious solitary leisure activities almost daily was prospectively associated with a lower risk of depression, feeling full of energy, and a lower risk of death by any cause. Occasionally engaging in these activities was prospectively associated with greater optimism and a lower risk of cognitive impairment. Engaging in serious social activities was prospectively associated with greater happiness, lower scores on the loneliness scale, a lower risk of Alzheimer's disease, and an increased risk of cancer. Additionally, occasionally engaging in serious social activities was associated with greater optimism and lower risk of depression, pain, and mobility limitations. These associations were independent of demographics, socioeconomic status, personality, history of diseases, and prior lifestyle. The sensitivity analyses provided substantial evidence for the robustness of these associations.

Discussion

Mind-engaging leisure activities can be considered a health and wellbeing resource. Practitioners may consider them tools that help middle-aged and older adults maintain their health and quality of life.

Bidirectional associations of intellectual and social activities with cognitive function among middle-aged and elderly adults in China

BACKGROUND

Previous studies evaluating the association between leisure activities and cognitive function produced conflicting results. Different types of leisure activities may have different effects on cognition, and very few studies have explored their bidirectional associations. Our study aimed to explore whether intellectual and social activities had bidirectional associations with cognitive function among the middle-aged and elderly adults in China.

METHODS

Data was derived from the China Health and Retirement Longitudinal Study. The data in this study were based on 11,549 participants aged 45 or older whose intellectual and social activities and cognitive function were assessed at baseline. Cross-lagged panel model was used to examine the temporal relationship of intellectual and social activities with cognitive function.

RESULTS

Totally, 5624 participants completed the third follow-up in 2018. The results showed that the better the cognitive function they had at baseline, the more intellectual activities they were engage in (β = 0.044, P < 0.001) and vice versa (β = 0.042, P = 0.001). Additionally, better cognitive function at baseline was significantly associated with more engagement in social activities (β = 0.028, P = 0.030); in contrast, higher engagement in social activities at baseline was not related to better cognitive function (β = -0.008, P = 0.523).

LIMITATIONS

Engagement in social and intellectual activities was assessed via questionnaire.

CONCLUSIONS

Our findings indicated that there was a bidirectional relationship between intellectual activities and cognitive function. However, participation in social activities did not slow down the decline in cognitive function. Participating in intellectual activities, compared to social activities, is especially beneficial for cognitive function.

Association of low meal frequency with decreased in vivo Alzheimer's pathology

Little is known about the association between meal frequency and Alzheimer's disease (AD) in humans. We tested the hypothesis that low meal frequency (LMF) is associated with reduced in vivo AD pathology in human brain, and additionally investigated the mediation of serum ghrelin, a hunger-related hormone, for the association. A total of 411 non-demented older adults were systematically interviewed to identify their dietary patterns including meal frequency and underwent multi-modal neuroimaging for cerebral beta-amyloid (Aβ) and tau deposition, glucose metabolism, and cerebrovascular injury. LMF (less than three meals a day) was significantly associated with lower Aβ deposition compared to high meal frequency (HMF). In addition, both LMF and reduced Aβ deposition were significantly related to elevated serum ghrelin. Our findings suggest that LMF may be related to the lower risk of AD through reduced brain amyloid deposition. Additionally, ghrelin appears mediate the association between LMF and lower amyloid deposition.

Accelerometer-Assessed Physical Activity and Cognitive Performance among European Adults Aged 50+: The Mediating Effects of Social Contacts and Depressive Symptoms

BACKGROUND

Cognitive decline is a major public health concern worldwide and it is vital to identify and better understand effective population-based means to improve cognitive performance in old age. The current study set out to examine the links between accelerometer-based physical activity with cognitive performance in later life, as well the indirect pathways through one's social network contacts and depression.

METHOD

We used data from 855 participants aged 50 and above who took part in a cross-sectional accelerometer study as part of the Survey of Ageing, Retirement and Health (SHARE). Cognitive function was measured as an average score of fluency, immediate and delayed recall tests, social contacts were the average contact frequency with members of the social support network, and depression was the Euro-D summary score of depressive symptoms. A multiple mediation analysis was conducted to test the direct and indirect associations between total physical activity (intensity gradient) and cognitive function, as well as the mediation of this association by social contacts and depressive symptoms.

RESULTS

Intensity of physical activity was directly related to better cognitive performance (B = 0.170, p = 0.007). The association was partially mediated by social contacts (B = 0.022, 95% CI 0.005, 0.046) and depressive symptoms (B = 0.009, 95% CI 0.009, 0.025), such that total physical activity was linked to cognitive health via more frequent contacts with network members and low depressive symptoms.

CONCLUSIONS

Practitioners might consider encouraging a physically active lifestyle that involves social interactions to support better cognitive aging and mental health.

Quantifying longitudinal cognitive resilience to Alzheimer's disease and other neuropathologies

INTRODUCTION

Cognitive resilience (CR) has been defined as the continuum of better (or worse) than expected cognition, given the degree of neuropathology. To quantify this concept, existing approaches focus on either cognitive level at a single time point or slopes of cognitive decline.

METHODS

In a prospective study of 1215 participants, we created a continuous measure of CR defined as the mean of differences between estimated person-specific and marginal cognitive levels over time, after accounting for neuropathologies.

RESULTS

Neuroticism and depressive symptoms were associated with all CR measures (P-values < .012); as expected, cognitive activity and education were only associated with the cognitive-level approaches (P-values < .0002). However, compared with the existing CR measures focusing on a single measure or slopes of cognition, our new measure yielded stronger relations with risk factors.

DISCUSSION

Defining CR based on the longitudinal differences between person-specific and marginal cognitive levels is a novel and complementary way to quantify CR.

Risk scores of incident mild cognitive impairment in a Beijing community-based older cohort

Objective: It is very important to identify individuals who are at greatest risk for mild cognitive impairment (MCI) to potentially mitigate or minimize risk factors early in its course. We created a practical MCI risk scoring system and provided individualized estimates of MCI risk.

Methods: Using data from 9,000 older adults recruited for the Beijing Ageing Brain Rejuvenation Initiative, we investigated the association of the baseline demographic, medical history, lifestyle and cognitive data with MCI status based on logistic modeling and established risk score (RS) models 1 and 2 for MCI. We evaluated model performance by computing the area under the receiver operating characteristic (ROC) curve (AUC). Finally, RS model 3 was further confirmed and improved based on longitudinal outcome data from the progression of MCI in a sub-cohort who had an average 3-year follow-up.

Results: A total of 1,174 subjects (19.8%) were diagnosed with MCI at baseline, and 72 (7.8%) of 849 developed MCI in the follow-up. The AUC values of RS models 1 and 2 were between 0.64 and 0.70 based on baseline age, education, cerebrovascular disease, intelligence and physical activities. Adding baseline memory and language performance, the AUC of RS model 3 more accurately predicted MCI conversion (AUC = 0.785).

Conclusion: A combination of risk factors is predictive of the likelihood of MCI. Identifying the RSs may be useful to clinicians as they evaluate their patients and to researchers as they design trials to study possible early non-pharmaceutical interventions to reduce the risk of MCI and dementia.

Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-β and consequent Alzheimer’s disease risk

Amyloid-β (Aβ) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer’s disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.–2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1’s role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aβ generation through inhibiting β-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.

Growth Mindset Predicts Cognitive Gains in an Older Adult Multi-Skill Learning Intervention

Growth mindset (belief in the malleability of intelligence) is a unique predictor of young learners' increased motivation and learning, and may have broader implications for cognitive functioning. Its role in learning in older adulthood is unclear. As part of a larger longitudinal study, we examined growth mindset and cognitive functioning in older adults engaged in a 3-month multi-skill learning intervention that included growth mindset discussions. Before, during, and after the intervention, participants reported on their growth mindset beliefs and completed a cognitive battery. Study 1 indicated that intervention participants, but not control participants, increased their growth mindset during the intervention. Study 2 replicated these results and found that older adults with higher preexisting growth mindsets showed larger cognitive gains at posttest compared to those with lower preexisting growth mindsets. Our findings highlight the potential role of growth mindset in supporting positive learning cycles for cognitive gains in older adulthood.

Healthy lifestyle and life expectancy with and without Alzheimer's dementia: population based cohort study

OBJECTIVE

To determine the impact of lifestyle factors on life expectancy lived with and without Alzheimer's dementia.

DESIGN

Prospective cohort study.

SETTING

The Chicago Health and Aging Project, a population based cohort study in the United States.

PARTICIPANTS

2449 men and women aged 65 years and older.

MAIN EXPOSURE

A healthy lifestyle score was developed based on five modifiable lifestyle factors: a diet for brain health (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay-MIND diet score in upper 40% of cohort distribution), late life cognitive activities (composite score in upper 40%), moderate or vigorous physical activity (≥150 min/week), no smoking, and light to moderate alcohol consumption (women 1-15 g/day; men 1-30 g/day).

MAIN OUTCOME

Life expectancy with and without Alzheimer's dementia in women and men.

RESULTS

Women aged 65 with four or five healthy factors had a life expectancy of 24.2 years (95% confidence interval 22.8 to 25.5) and lived 3.1 years longer than women aged 65 with zero or one healthy factor (life expectancy 21.1 years, 19.5 to 22.4). Of the total life expectancy at age 65, women with four or five healthy factors spent 10.8% (2.6 years, 2.0 to 3.3) of their remaining years with Alzheimer's dementia, whereas women with zero or one healthy factor spent 19.3% (4.1 years, 3.2 to 5.1) with the disease. Life expectancy for women aged 65 without Alzheimer's dementia and four or five healthy factors was 21.5 years (20.0 to 22.7), and for those with zero or one healthy factor it was 17.0 years (15.5 to 18.3). Men aged 65 with four or five healthy factors had a total life expectancy of 23.1 years (21.4 to 25.6), which is 5.7 years longer than men aged 65 with zero or one healthy factor (life expectancy 17.4 years, 15.8 to 20.1). Of the total life expectancy at age 65, men with four or five healthy factors spent 6.1% (1.4 years, 0.3 to 2.0) of their remaining years with Alzheimer's dementia, and those with zero or one healthy factor spent 12.0% (2.1 years, 0.2 to 3.0) with the disease. Life expectancy for men aged 65 without Alzheimer's dementia and four or five healthy factors was 21.7 years (19.7 to 24.9), and for those with zero or one healthy factor life expectancy was 15.3 years (13.4 to 19.1).

CONCLUSION

A healthy lifestyle was associated with a longer life expectancy among men and women, and they lived a larger proportion of their remaining years without Alzheimer's dementia. The life expectancy estimates might help health professionals, policy makers, and stakeholders to plan future healthcare services, costs, and needs.

Modifiable psychosocial risk factors and delayed onset of dementia in older populations: analysis of two prospective US cohorts

OBJECTIVE

Preventing Alzheimer's dementia (AD) fundamentally equates to delaying onset. Thus, we quantified associations of modifiable, psychosocial risk factors to years of delayed onset of dementia.

DESIGN

Two prospective cohorts (n=2860) with negative and positive psychosocial factors measured at baseline (depressive symptoms, neuroticism, cognitive activity).

SETTING AND PARTICIPANTS

Religious Orders Study of older priests, nuns and brothers across the USA, initiated in 1994; Rush Memory and Aging Project, of older persons in Chicago area, initiated in 1997.

OUTCOME MEASURE

We conducted annual neurological and neuropsychological assessments to identify AD (n=785 incident cases). We compared age at diagnosis of AD across psychosocial risk factor groups, controlling for confounders, using accelerated failure time models.

RESULTS

We found strong relations of three or more depressive symptoms with age at AD diagnosis; estimated mean age at diagnosis was 86.9 years with significant symptoms versus 92.1 years with no symptoms (p=0.001). In addition, neuroticism was inversely related to age at AD diagnosis; estimated mean age at diagnosis was 88.8 years for the highest neuroticism tertile and 93.1 years in the lowest tertile (p<0.001). Participants with higher cognitive activity (such as reading books) had later AD diagnosis; estimated mean age at diagnosis was 89.2 years for the lowest cognitive activity group and 92.6 years for the highest activity group (p<0.001).

CONCLUSIONS

Higher depressive symptoms were associated with 5-year acceleration in AD; higher neuroticism with 4-year acceleration and higher cognitive activity with a 3.5-year delay. To translate findings, prior health services research in the USA indicates delaying dementia 5 years could add 3 years of life and reduce individual costs of care >$60 000. These results provide a rigorous, easily translatable metric for communicating and evaluating the potential public health impact of psychosocial and experiential interventions.

Longitudinal Relationship of Leisure Activity Engagement With Cognitive Performance Among Non-Demented, Community-Dwelling Older Adults

BACKGROUND AND OBJECTIVES

Leisure activity engagement (LAE) may reduce the risk of incident dementia. However, cognitive performance may predict LAE change. We evaluated the temporal ordering of overall and subtypes of LAE (intellectual, physical, and social) and cognitive performance (global, language, memory, and visuospatial function) among non-demented older adults.

RESEARCH DESIGN AND METHODS

The Washington Heights-Inwood Columbia Aging Project concurrently administered a survey measure of 13 leisure activities and a neuropsychological battery every 18-24 months for up to 14 years to 5,384 racially and ethnically diverse participants. We used parallel process conditional latent growth curve models to examine temporal ordering in the overall sample and within baseline diagnostic groups (mild cognitive impairment [MCI] vs. cognitively normal).

RESULTS

Levels and changes of overall and subtypes of LAE were positively correlated with cognitive performance in the overall sample and within each diagnostic group. In the overall sample, higher initial memory was associated with slower declines in social LAE (estimate = 0.019, 95% confidence interval [95% CI]: 0.001-0.037). Among MCI, higher initial physical LAE was associated with slower declines in memory (estimate = 0.034, 95% CI: 0.001-0.067), but higher initial intellectual LAE was related to steeper declines in visuospatial function (estimate = -0.028, 95% CI: -0.052 to -0.004). Among cognitively normal, higher initial memory was associated with slower declines in intellectual LAE (estimate = 0.012, 95% CI: 0.002-0.022).

DISCUSSION AND IMPLICATIONS

Dynamic interplay of LAE with cognitive performance was observed across diagnostic groups. Levels of LAE subtypes could be more predictive of change in certain cognitive domains within older adults with MCI.

Cognitive reserve proxies, Alzheimer pathologies, and cognition

This study aimed to explore the moderating effects of the frequently used cognitive reserve (CR) proxies [i.e., education, premorbid intelligence quotient (pIQ), occupational complexity (OC), and lifetime cognitive activity (LCA)] on the relationships between various in vivo Alzheimer's disease (AD) pathologies and cognition. In total, 351 [268 cognitively unimpaired (CU), 83 cognitive impaired (CI)] older adults underwent multi-modal brain imaging to measure AD pathologies and cognitive assessments, and information on CR proxies was obtained. For overall participants, only education moderated the relationship between Aβ deposition and cognition. Education, pIQ, and LCA, but not OC, showed moderating effect on the relationship between AD-signature cerebral hypometabolism and cognition. In contrast, only OC had a moderating effect on the relationship between cortical atrophy of the AD-signature regions and cognition. Such moderation effects of the CR proxies were similarly observed in CI individuals, but most of them were not in CU individuals. The findings suggest that the proposed CR proxies have different moderating effects on the relationships between specific AD pathologies and cognition.

Personality Change Profiles and Changes in Cognition Among Middle-Aged and Older Adults

Research on the relationship between personality traits and cognitive abilities has primarily used cross-sectional designs and considered personality traits individually in relation to cognitive dimensions. This study (N = 2,652) examined the relationship between Big Five personality change profiles and change in cognitive factors, episodic memory and executive functioning. Latent profile analysis was used to capture patterns of change across the Big Five traits. Three profiles of personality change were defined: Decreasers, Maintainers, and Increasers. The Decreasers declined more in episodic memory compared to the Increasers and Maintainers. Also, the Decreasers declined more in executive functioning compared to the Increasers, but not the Maintainers. The findings advance our understanding of the links between patterns of personality change and cognitive aging.

Influence of Cognitive Reserve on Cognitive Trajectories: Role of Brain Pathologies

BACKGROUND AND OBJECTIVES

Evidence on the association of cognitive reserve (CR) with the cognitive trajectories is limited. We aimed to examine the influence of CR indicator on domain-specific cognitive trajectories taking brain pathologies into account.

METHODS

Within the Rush Memory and Aging Project, 1,697 participants without dementia (mean age 79.6 years) were followed up to 21 years. CR indicator encompassing education, early-life, mid-life, and late-life cognitive activities and late-life social activity was ascertained at baseline and categorized as tertiles (lowest, middle, and highest). Global cognition, episodic memory, semantic memory, working memory, visuospatial ability, and perceptual speed were assessed annually with 19 tests, from which composite scores were derived. During the follow-up, 648 participants died and underwent autopsies to evaluate brain pathologies. Data were analyzed using linear mixed-effect models.

RESULTS

Among the participants, the score of the CR indicator ranged from -8.00 to 5.74 (mean 0.00 ± 2.23). In multi-adjusted mixed-effect models, compared to the lowest CR, the highest was related to a slower decline in global cognition (β = 0.028, 95% confidence interval [CI] 0.012-0.043), episodic memory (β = 0.028, 95% CI 0.010-0.047), and working memory (β = 0.019, 95% CI 0.005-0.033) during the follow-up. In brain pathologic data analysis, the association of the highest CR with cognitive function changes remained significant among participants with high Alzheimer disease pathology or gross infarcts.

DISCUSSION

High CR indicator is associated with preserved global cognitive function, episodic memory, and working memory, even in the presence of brain pathologies. Our findings highlight the important role of high CR accumulation in the prevention of cognitive decline.

Reducing Your Risk of Alzheimer's Dementia: Building a Better Brain as We Age

Alzheimer' dementia is a large and growing public health problem. Of utmost importance for limiting the impact of the disease on society is the prevention of dementia, that is, delay onset either by years whereby death ensues prior to dementia onset. The Religious Orders Study and the Rush Memory and Aging Project are two harmonized cohort studies of aging and dementia that include organ donation at death. Ongoing since 1994 and 1997, respectively, we published on the association of numerous experiential, psychological, and medical risk factors for dementia, many of which are potentially modifiable. Here, selected findings are reviewed based on a presentation at the 2020 National Academy of Neuropsychology given virtually in Chicago in October of 2020.

Leisure Activities, APOE ε4, and Cognitive Decline: A Longitudinal Cohort Study

Background: Both leisure activities and the ε4 allele of the apolipoprotein E (APOE ε4) have been shown to affect cognitive health. We aimed to determine whether engagement in leisure activities protects against APOE ε4-related cognitive decline.

Methods: We used the cohort data from the Chinese Longitudinal Healthy Longevity Survey. A total of 3,017 participants (mean age of 77.0 years, SD = 9.0; 49.3% female) from 23 provinces of China were recruited in 2008 and were reinterviewed in 2014. We assessed cognitive function using the Mini-Mental State Examination (MMSE). We calculated cognitive decline using subtraction of the MMSE score of each participant in 2008 and 2014. We genotyped a number of APOE ε4 alleles for each participant at baseline and determined the Index of Leisure Activities (ILAs) by summing up the frequency of nine types of typical activities in productive, social, and physical domains. We used ordinal logistic regression models to estimate the effects of leisure activities, APOE ε4, and their interaction on cognitive decline, statistically adjusted for a range of potential confounders.

Results: There were significant associations between APOE ε4 and faster cognitive decline, independent of potential confounders, and between leisure activities and mitigated cognitive decline. The odds ratios were 1.25 (95% CI: 1.03, 1.53) and 0.93 (95% CI: 0.89, 0.97), respectively. We found significant interactions of APOE ε4 with leisure activities with a P-value of 0.018. We also observed interactive effects of subtypes of leisure activities: participants who regularly engaged in productive activities were more likely to reduce the risk of APOE ε4-related cognitive decline.

Conclusion: Our findings provide support for the indication that participating in leisure activities reduces the risk of APOE ε4-related cognitive decline.

Staging of Dementia Severity With the Hong Kong Version of the Montreal Cognitive Assessment (HK-MoCA)'s

BACKGROUND

The Hong Kong version of Montreal Cognitive Assessment (HK-MoCA) has been used to screen for dementia, but it has not been validated to delineate the stages of Alzheimer disease (AD). This study aimed to determine the cut-off score ranges for mild, moderate, and severe AD.

METHODS

The HK-MoCA score was matched against the Clinical Dementia Rating on 155 patients with AD. Investigators performing the HK-MoCA and Clinical Dementia Rating were blinded to each other. Receiver-operating characteristic analysis was used to determine the cut-off scores between different stages of AD (mild, moderate, and severe stage). A secondary analysis with adjustments for age and education received were also performed.

RESULT

The cut-off score in HK-MoCA was ≤4 for those with severe AD (sensitivity 84.4%, specificity 91.9%, area under curve=0.92, P<0.001) and 5 to 9 for those with moderate AD (sensitivity 86.3%, specificity of 93.3%, area under curve=0.953, P<0.001). With adjustments for age and education, the cut-off score for moderate AD was adjusted to 5 to 8, whereas the cut-off score for severe AD remained unchanged.

CONCLUSIONS

The severity of AD could be delineated using the HK-MoCA for the Cantonese-speaking population in Hong Kong, and the effect of education on the cut-off score needs further investigation.

Cognitive Activity and Onset Age of Incident Alzheimer Disease Dementia

OBJECTIVE

To test the hypothesis that higher level of cognitive activity predicts older age at dementia onset in Alzheimer disease (AD) dementia.

METHODS

As part of a longitudinal cohort study, 1,903 older persons without dementia at enrollment reported their frequency of participation in cognitively stimulating activities. They had annual clinical evaluations to diagnose dementia and AD, and the deceased underwent neuropathologic examination. In analyses, we assessed the relation of baseline cognitive activity to age at diagnosis of incident AD dementia and to postmortem markers of AD and other dementias.

RESULTS

During a mean of 6.8 years of follow-up, 457 individuals were diagnosed with incident AD at a mean age of 88.6 (SD 6.4, range 64.1-106.5) years. In an extended accelerated failure time model, higher level of baseline cognitive activity (mean 3.2, SD 0.7) was associated with older age at AD dementia onset (estimate 0.026; 95% confidence interval 0.013-0.039). Low cognitive activity (score 2.1, 10th percentile) was associated with a mean onset age of 88.6 years compared to a mean onset age of 93.6 years associated with high cognitive activity (score 4.0, 90th percentile). Results were comparable in subsequent analyses that adjusted for potentially confounding factors. In 695 participants who died and underwent a neuropathologic examination, cognitive activity was unrelated to postmortem markers of AD and other dementias.

CONCLUSION

A cognitively active lifestyle in old age may delay the onset of dementia in AD by as much as 5 years.

Risk of Dementia Differs across Lifestyle Engagement Subgroups: A Latent Class and Time to Event Analysis in Community-Dwelling Older Adults

OBJECTIVES

Better understanding of the lifestyle activities shared among older adult subgroups may inform further health-behavioral interventions that can be deployed at the group or community level. We applied latent class analysis to characterize qualitatively distinct lifestyle engagement groups, examined their differential risk of incident dementia, and compared their predictive utility to traditional activity frequency and variety scores.

METHOD

Participants were from the Ginkgo Evaluation of Memory Study (N=3,068, Mean age=78.5). Lifestyle activities were measured at baseline using the Lifestyle Activity Questionnaire. All-cause dementia was screened every six months and cases were clinically adjudicated. Median follow-up was 6 years. Time to dementia was assessed using discrete-time proportional hazards models, adjusted for demographic and health covariates.

RESULTS

Latent classes provided slightly poorer case discrimination than the frequency scores but identified distinct qualitative subgroups. In the four-class model, the Variety (22%) and Intellectual (18%) lifestyle groups had high engagement in intellectual activities, whereas the Variety and Social groups (32%) had high engagement in formal social activities. Compared to the Least Active group (28%), the Variety (HR=.67, 95% CI:(.48,.93)) and Intellectual (HR=.65, 95% CI:(.45,.93)) groups had significantly lower risk of incident dementia, but only among those without prevalent MCI.

DISCUSSION

Older adults highly engaged in intellectual activities, but not necessarily social activities, had the lowest risk of incident dementia. Activity frequency scores provided only slightly better case discrimination than activity variety scores and latent classes. Latent classes of older adults differed by their amount and types of activities, which may inform intervention design.

Genetic risk, adherence to a healthy lifestyle, and cognitive decline in African Americans and European Americans

INTRODUCTION

We investigated the role of genetic risk and adherence to lifestyle factors on cognitive decline in African Americans and European Americans.

METHODS

Using data from the Chicago Health and Aging Project (1993-2012; n = 3874), we defined the genetic risk based on presence of apolipoprotein E (APOE) ε 4 allele and determined a healthy lifestyle using a scoring of five factors: non-smoking, exercising, being cognitively active, having a high-quality diet, and limiting alcohol use. We used linear mixed-effects models to estimate cognitive decline by genetic risk and lifestyle score.

RESULTS

APOE  ε 4 allele was associated with faster cognitive decline in both races. However, within APOE  ε 4 carriers, adherence to a healthy lifestyle (eg., 4 to 5 healthy factors) was associated with a slower cognitive decline by 0.023 (95% confidence interval [CI] 0.004, 0.042) units/year in African Americans and 0.044 (95% CI 0.008, 0.080) units/year in European Americans.

DISCUSSION

A healthy lifestyle was associated with a slower cognitive decline in African and European Americans.

Joint trajectories of episodic memory and odor identification in older adults: patterns and predictors

Emerging evidence suggests that olfactory function is closely linked to memory function. The aims of this study were to assess whether olfactory and episodic memory functions follow similar age-related decline trajectories, to identify different patterns of decline, as well as predictors of the patterns. 1023 participants from the Memory and Aging Project were followed for up to 8 years with annual episodic memory and odor identification assessments. Trajectories were modelled using growth mixture models. Multivariate logistic regression was used to identify pattern predictors. Three patterns of joint trajectories were identified; Class 1- stable average performance in both functions (n=690, 67.4%); Class 2- stable average episodic memory and declining odor identification (n=231, 22.6%); and Class 3- decline in both functions (n= 102, 10.0%). Class predictors included age, sex, APOE ε4 status, cognitive activity level and BMI. Participants in Class 3 were most likely to develop dementia. Episodic memory and olfactory function show similar trajectories in aging. Such classification can contribute to a better understanding of the factors related to cognitive decline and dementia.

Impact of the Apolipoprotein E ε4 Allele on the Relationship Between Healthy Lifestyle and Cognitive Decline: A Population-Based Study

Adherence to a healthy lifestyle-characterized by abstaining from smoking, being physically and cognitively active, having a high-quality diet, and limiting alcohol use-is associated with slower cognitive decline in older adults, but whether this relationship extends to persons with a genetic predisposition (e.g., carriers of the ε4 allele of the apolipoprotein E gene (APOE*E4)) remains uncertain. Using data from a population-based study, the Chicago Health and Aging Project (Chicago, Illinois), we followed 3,886 individuals who underwent regular clinical and cognitive assessments from 1993 to 2012. Of 3,886 older adults, 1,269 (32.7%) were APOE*E4 carriers. Compared with noncarriers, APOE*E4 carriers had faster cognitive decline (β = -0.027 units/year, 95% confidence interval (CI): -0.032, -0.023). In contrast, persons with 2-3 and 4-5 healthy lifestyle factors had slower cognitive decline (β = 0.008 units/year (95% CI: 0.002, 0.014) and β = 0.019 units/year (95% CI: 0.011, 0.026), respectively) compared with those with 0-1 factor. In analyses stratified by APOE*E4 status, adherence to a healthy lifestyle (e.g., 4-5 factors vs. 0-1 factors) was associated with a slower rate of cognitive decline in both APOE*E4 carriers (β = 0.029, 95% CI: 0.013, 0.045) and noncarriers (β = 0.013, 95% CI: 0.005, 0.022). These results underscore the impact of a healthy lifestyle on cognition, particularly among persons with a genetic predisposition, who are more vulnerable to cognitive decline as they age.

Association of Lifestyle Activities with Functional Brain Connectivity and Relationship to Cognitive Decline among Older Adults

This study examines the relationship of engagement in different lifestyle activities to connectivity in large-scale functional brain networks, and whether network connectivity modifies cognitive decline, independent of brain amyloid levels. Participants (N = 153, mean age = 69 years, including N = 126 with amyloid imaging) were cognitively normal when they completed resting-state functional magnetic resonance imaging, a lifestyle activity questionnaire, and cognitive testing. They were followed with annual cognitive tests up to 5 years (mean = 3.3 years). Linear regressions showed positive relationships between cognitive activity engagement and connectivity within the dorsal attention network, and between physical activity levels and connectivity within the default-mode, limbic, and frontoparietal control networks, and global within-network connectivity. Additionally, higher cognitive and physical activity levels were independently associated with higher network modularity, a measure of functional network specialization. These associations were largely independent of APOE4 genotype, amyloid burden, global brain atrophy, vascular risk, and level of cognitive reserve. Moreover, higher connectivity in the dorsal attention, default-mode, and limbic networks, and greater global connectivity and modularity were associated with reduced cognitive decline, independent of APOE4 genotype and amyloid burden. These findings suggest that changes in functional brain connectivity may be one mechanism by which lifestyle activity engagement reduces cognitive decline.

Association of Early-Life Cognitive Enrichment With Alzheimer Disease Pathological Changes and Cognitive Decline

Importance

Indicators of early-life cognitive enrichment (ELCE) have been associated with slower cognitive decline and decreased dementia in late life. However, the mechanisms underlying this association have not been elucidated.

Objective

To examine the association of ELCE with late-life Alzheimer disease (AD) and other common dementia-related pathological changes.

Design, Setting, and Participants

This clinical-pathological community-based cohort study, the Rush Memory and Aging Project, followed up participants before death for a mean (SD) of 7.0 (3.8) years with annual cognitive and clinical assessments. From January 1, 1997, through June 30, 2019, 2044 participants enrolled, of whom 1018 died. Postmortem data were leveraged from 813 participants. Data were analyzed from April 12, 2019, to February 20, 2020.

Exposures

Four indicators of ELCE (early-life socioeconomic status, availability of cognitive resources at 12 years of age, frequency of participation in cognitively stimulating activities, and early-life foreign language instruction) were obtained by self-report at the study baseline, from which a composite measure of ELCE was derived.

Main Outcomes and Measures

A continuous global AD pathology score derived from counts of diffuse plaques, neuritic plaques, and neurofibrillary tangles.

Results

The 813 participants included in the analysis had a mean (SD) age of 90.1 (6.3) years at the time of death, and 562 (69%) were women. In a linear regression model controlled for age at death, sex, and educational level, a higher level of ELCE was associated with a lower global AD pathology score (estimate, -0.057; standard error, 0.022; P = .01). However, ELCE was not associated with any other dementia-related pathological changes. In addition, a higher level of ELCE was associated with less cognitive decline (mean [SD], -0.13 [0.19] units per year; range, -1.74 to 0.85). An indirect effect through AD pathological changes constituted 20% of the association between ELCE and the rate of late-life cognitive decline, and 80% was a direct association.

Conclusions and Relevance

These findings suggest that ELCE was associated with better late-life cognitive health, in part through an association with fewer AD pathological changes.

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.

Cognitive leisure activity and all-cause mortality in older adults: a 4-year community-based cohort

BACKGROUND

Cognitive leisure activity, such as reading, playing mahjong or cards and computer use, is common among older adults in China. Previous studies suggest a negative correlation between cognitive leisure activity and cognitive impairment. However, the relationship between cognitive leisure activity and all-cause mortality has rarely been reported.

OBJECTIVES

This study aims to explore the relationships between cognitive leisure activity and all-cause mortality in a community-based older people cohort in China.

METHODS

The current study sample comprised 4003 community residents aged ≥60 y who were enrolled in June 2015, and were followed up every year from 2015 to 2018. Reading, playing mahjong or cards and computer use were measured by questionnaires and summed into a cognitive leisure activity index (CLAI) score. Time-Dependent Cox Regression Model and Kaplan-Meier survival analysis were used to examine the association of cognitive leisure activity with all-cause mortality.

RESULTS

During the 4-year follow-up of 4003 participants, 208 (5.2%) deaths were registered. Of all participants, 66.8, 26.7, 6.1 and 0.35% reported CLAI scores of 0, 1, 2 and 3, respectively. A strong association was noted between the CLA score and all-cause mortality (adjusted hazard ratio [HR] = 0.72, 95% confidence intervals [CI]: 0.54-0.97, P = 0.028). Stratified analysis suggested that a higher CLAI score was significantly associated with a decreased risk of all-cause mortality mainly among those who were male, aged ≥80 y, cognitively impaired, and not diagnosed with cancer (P < 0.05).

CONCLUSION

Cognitive leisure activity was positively associated with reduced risk of death from all cause among the older people in major city of China, which helped promote a comprehensive understanding of health characteristics at advanced ages.

The Role of Polygenic Score and Cognitive Activity in Cognitive Functioning Among Older Adults

BACKGROUND AND OBJECTIVES

This study explored whether the intensity of cognitive activities could moderate the relationship between a genetic predisposition for developing Alzheimer's disease (AD) and cognitive functioning among older adults in the United States. Furthermore, we examined whether the same moderating effects were dependent on different measures of cognition.

RESEARCH DESIGN AND METHODS

We used a data set from the 2000-2014 waves of the Health and Retirement Study and the Consumption and Activities Mail Survey. Our sample included 3,793 individuals aged 50 or older. We used the polygenic score (PGS) for AD as a genetic trait for cognitive functioning. Reading, listening to music, using a computer, playing cards/games/solving puzzles, singing/playing musical instruments, and creating art and crafts were included as cognitive activities, and TV viewing as passive activities. We used total cognition, fluid intelligence, and crystallized intelligence as proxies for cognitive functioning. Growth-curve models were conducted.

RESULTS

After controlling for covariates, we found that reading books, using a computer, and playing cards/games/solving puzzles had a positive effect on cognitive functioning. An additional hour spent reading books moderated the negative effect of AD PGS on cognition. The measure of fluid, when compared with crystallized intelligence, appeared to drive these results.

DISCUSSION AND IMPLICATIONS

Reading could be a protective factor against cognitive decline among older adults who are genetically predisposed to developing AD. Implications for individuals, caregivers, clinicians, and policymakers are suggested. Furthermore, the onset of AD in those at greater genetic risk may be delayed with this intervention.