Trajectories Of Cognitive Aging Research Articles

Disparate trajectories of cognitive aging among American Indian and Alaskan Native people with and without HIV.

This study describes trajectories of cognitive aging among American Indian/Alaskan Native (AI/AN) adults with and without HIV and the role of immunosenescence longitudinally. We characterized trajectories of cognitive aging in a sample of 333 AI/AN and 309 non-Hispanic White (NHW) adults who were followed longitudinally for up to 20 years by the HIV Neurobehavioral Research Program (HNRP) across six U.S. research sites. We used growth curve modeling with autoregressive Lag-1 structures and heterogeneous residual variances to assess the role of ethnoracial identity and HIV grouping upon decline in trajectories of cognitive aging. HIV- AI/AN adults demonstrated earlier and steeper decline in normative trajectories of cognitive aging on tasks of processing speed, timed tasks of attention/working memory, executive function, and psychomotor speed in comparison to HIV- NHW adults. Accentuated trajectories of cognitive aging were evident in both HIV+ and HIV+ immunosuppressed groups in comparison to HIV- peers and were primarily driven by the role of immunosenescence. AI/AN disparities in trajectories of cognitive aging are evident and are likely explained by the interplay of biopsychosociocultural factors, including immunosenescence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Predicting brain atrophy and cognitive aging trajectories with baseline subjective cognitive concerns in cognitively normal older adults

Subjective cognitive concerns (SCC) are common even in cognitively normal older adults who lack objectively-detectable deficits on standard neuropsychological evaluation. The clinical relevance of these concerns, particularly considering the nature of concerns (e.g., memory versus non-memory), remains unclear. Thus, we examined whether baseline memory and non-memory SCC relate to longitudinal change in brain volume and neuropsychological test performance in 476 functionally-intact, objectively unimpaired older adults (Mage = 72y, 56 % female, follow-up time = 1 – 9 years). Mixed-effects models revealed that both higher baseline memory and non-memory SCC predicted greater atrophy in total gray matter and dorsolateral prefrontal cortex atrophy over time, while only memory SCC predicted steeper medial temporal lobe atrophy. Regarding neuropsychological performance, higher non-memory SCC predicted decline in processing speed performance, while memory SCC did not predict neuropsychological trajectories. SCC are a risk factor for more adverse brain and cognitive aging trajectories, even in functionally-intact, seemingly cognitively normal older adults.

Supplemental Material for Disparate Trajectories of Cognitive Aging Among American Indian and Alaskan Native People With and Without HIV

Supplemental Material for Disparate Trajectories of Cognitive Aging Among American Indian and Alaskan Native People With and Without HIV

THE ROLE OF CONTEXTUAL FACTORS IN ADULT DEVELOPMENT AND AGING

Abstract Individual development is embedded in multiple environmental systems, ranging from broader distal cultural and historical contexts to more proximal residential, family, and partnership contexts. The goal of this symposium is to showcase research studying the role of distal and proximal contextual factors in the development and aging of key domains, including health, cognitive function, social relationships, and emotional experiences. Nakagawa et al. examine cultural differences in the associations of positive affect and loneliness with longevity using data from prospective surveys in the United States (1986–2005) and Japan (1987–2006). Hülür et al. use 35-year longitudinal data (1977-2012) from 3,482 participants of the Seattle Longitudinal Study to examine associations between perceived residential neighborhood characteristics and trajectories of cognitive aging. Kobayashi et al. study cohort and gender differences in trajectories of social contact and social participation and the effects of being married and living with a child using data from the National Survey of the Japanese Elderly (1987-2021). Meier et al. will present data from a study on emotional co-regulation in younger and older couples’ daily lives focusing on situational factors (e.g., psychological availability) within romantic relationships that can shape daily emotional experiences and relationship quality. The discussion by Hans-Werner Wahl will focus on how these approaches contribute to our understanding of processes of context dynamics and how they can be utilized to promote the maintenance of health and function in aging.

A COMPARISON OF THE IMPACT OF ADVERSE CHILDHOOD EXPERIENCES ON BRAIN HEALTH IN LATINA AND NON-LATINA WOMEN

Abstract Early-life experiences and social determinants of health influence late-life cognitive performance, cognitive aging trajectories, and risk of Alzheimer’s disease and related dementias (ADRD). Research shows adversity during childhood plays a central role in health outcomes later in life, such that more adverse childhood experiences (ACEs) predict higher likelihood of negative physical and mental health outcomes. As ACEs may also predict neurocognitive performance and historically marginalized groups are disproportionately exposed to ACEs, this study aims to enhance diversity in research on ACEs and cognitive aging by clarifying the role of ethnicity. Latinos are 51% more likely to experience ACEs and 1.5x more likely to experience ADRD than their non-Latino counterparts. Data were collected in two studies assessing cognitive functioning in women aged 65-85 who reported no ACEs or 3+ ACEs (54 non-Latinas, Oklahoma; 50 Latinas, Rhode Island). ACEs were measured with the Adverse Childhood Experiences Questionnaire. Cognition was measured using NIH Toolbox Cognition-Battery and Automated Neuropsychological Assessment Metrics. In the non-Latina white sample (Mage=73.2), those with 3+ ACEs exhibited inferior scores on Stroop Interference, p=.050, d=-.44. The ACEs group demonstrated higher scores on List Sorting, p=.003, d=-.78. Small effects were found in Stroop Color, Stroop Color-Word, Cognition Fluid Composite, Flanker, and Cart Sort (d=-.25, -.39, -.29, .24, -.25, respectively). These findings are compared to those within the Latina sample, demonstrating the need to extend research on life course risk factors for ADRD to this underrepresented group, which is at elevated risk of both ACEs and ADRD.

CONTEXTUALIZING HOW DAILY DISCRIMINATION EXPERIENCES IMPACT EVERYDAY METAMEMORY

Abstract Examining day-to-day responses to everyday stressors, such as discrimination, contextualizes how cognitive aging trajectories may vary across the lifespan. Furthermore, recent research investigating stress-induced impairment of metamemory may address the relationship between discrimination experiences and cognitive impairment. This study sought to articulate the association between daily experiences of discrimination and impaired metamemory across the lifespan, as defined by the number of subjective cognitive complaints, using data collected from the Midlife in the United States Refresher Study Daily Diary Project (N = 782; ages 20-75; M = 47.91 years, SD = 12.67 years). A two-level linear mixed model was conducted to examine the within and between-persons relationships concerning lifetime and daily experiences of discrimination, daily affect balance, baseline objective cognitive performance, and sociodemographic variables (age, race, ethnicity, and sex) on impaired everyday metamemory. Results from linear mixed model analyses showed significant within-person fixed effects of daily discrimination and daily affect balance on metamemory accuracy, as well as significant between-persons fixed effects of race and ethnicity on metamemory accuracy. Furthermore, significant interactions were found between race and daily discrimination experiences, ethnicity and daily discrimination experiences, daily affect balance and daily discrimination experiences, daily affect balance and age, and endorsement of lifetime experiences of discrimination and daily discrimination experiences on day-to-day metamemory accuracy. These findings extend our understanding of how discrimination experiences may impair metacognitive processes and demonstrate the need for more research into understanding metamemory accuracy as an underlying mechanism by which the psychosocial stressor of discrimination impacts cognition across the lifespan.

Longitudinal Trajectories of Normal versus Abnormal Cognitive Aging in the SIU Longitudinal Cognitive Aging Study as measured by the original Alzheimer’s disease Assessment Scale and a novel extended version

AbstractBackgroundThe original Alzheimer’s disease Assessment Scale‐cognitive subscale (oADAS) is a common measure of cognition used in Alzheimer’s disease (AD) clinical trials. The oADAS may not be sensitive to pre‐dementia syndromes such as mild cognitive impairment (MCI), possibly due to ceiling effects for many of the subtests. However, little is known about the trajectories of cognitive aging on the oADAS in cognitively‐normal individuals who decline over time. We used Linear Mixed Effects Modeling to examine trajectories of cognitive aging on the oADAS, a novel extended version (eADAS), and the MMSE. We hypothesized that, compared to non‐decliners, individuals who declined from normal to MCI and/or AD (decliners) would demonstrate increased error scores on the ADAS and lower scores on the MMSE over time.MethodsWe included data from 608 older adults (72% female, mean age = 69.0 years) who were enrolled in SIU Longitudinal Cognitive Aging Study (LCAS). Total years of educational attainment ranged from 8‐26 years. The vast majority of the participants were White/Not‐Hispanic. There were 50 decliners and 558 non‐decliners included in the present analysis. The eADAS included short‐delay recall/recognition trials for the first word list, a short‐delay true‐false word recognition trial for the second word list, a letter‐digit d psychomotor test, supermarket fluency, spontaneous clock drawing, three additional items to the object naming subtest, three additional figure copies, and a similarities test. All analyses were completed after controlling for gender, education, age at first visit, time between visits, and number of visits.ResultsThere was no significant difference between the groups for age at first visit. Greater age at first visit and lower education were associated with increased error scores for both ADAS versions and MMSE in the decliner group (p’s <0.001). There was no significant effect of the number of days between visits. The mean coefficients for the change in error score over time between visits for the oADAS, eADAS, and MMSE was 2.84, 10.30, and ‐1.09, respectively.ConclusionOur results indicate that the oADAS and eADAS are useful measures for examining trajectories of cognitive decline in cognitively‐normal individuals at increased risk for AD.

Impact of Mid‐ and Late‐Life Diabetes in the Trajectories of Cognitive Aging in a Bi‐ethnic Cohort of Mexican Americans and Non‐Hispanic White Older Adults

AbstractBackgroundMidlife vascular risk factors, including diabetes, have been associated with an increased risk of Alzheimer’s disease (AD) and related dementias (ADRD). Hispanics experience both a higher burden of cardiometabolic diseases and AD/ADRD compared with non‐Hispanic White older adults. However, there is a lack of diversity in AD/ADRD research, and additional investigations are needed to understand the impact of cardiometabolic diseases in AD/ADRD disparities. We aimed to investigate the association of mid‐ and late‐life diabetes with cognitive decline in Mexican American (MA) and Non‐Hispanic White (NHW) adults.MethodWe included participants from the San Antonio Heart Study (SAHS), initiated in 1979 to examine ethnic differences in diabetes and cardiovascular disease between MA and NHW. In 1992, SAHS participants were invited to the San Antonio Longitudinal Study of Aging (SALSA), in which cognitive function was assessed using the MMSE at four time points. The latent variable mixture model implemented in Mplus was used to identify statistically distinct classes in cognitive trajectories based on repeated MMSE scores. The Bolck‐Croon‐Hagenaars method was used to test covariate differences across classes. Participants with missing data in 2 or more MMSE scores or covariates were excluded from the analysis.ResultOur analytical sample included 337 participants (52.2% MA, 60.8% women, Table 1). Two distinct classes were identified (Shannon’s entropy = 0.813). Participants within class 1 had a steeper cognitive decline (0.53‐point drop per follow‐up), whereas those in class 2 appeared more stable (0.17‐point drop per follow‐up). Compared to class 2, participants in class 1were 2.1 and 2.5 times more likely to have diabetes during midlife (p = 0.019) and late‐life (p = 0.002) respectively. In contrast, ethnic‐stratified analysis revealed significant findings only among MA (Table 2), where participants in class 1 were 2.4 times more likely to have diabetes in midlife (p = 0.023) and 1.8 times in late life (p = 0.005) compared to class 2.ConclusionDiabetes was related to a steeper cognitive decline, particularly among MAs with prevalent diabetes in midlife. These findings provide new insights into the role of vascular burden in cognitive decline disparities among MAs. Further analysis exploring additional vascular factors are underway in this unique population.

Effect of early‐ and mid‐life cognitive enrichment on Alzheimer’s disease pathology and late‐life cognition

AbstractBackgroundCognitive reserve and brain maintenance may explain individual differences in trajectories of cognitive and brain aging due to various life exposures (e.g., education, cognitive enrichment). Cognitive reserve refers to the advantages that life exposures exert on cognitive abilities despite brain aging or disease; brain maintenance refers to the protective effects of life exposures on the brain itself (e.g., reduced rate of neuropathology accumulation). Previous findings showed that early‐life cognitive enrichment (ELCE) was associated with slower cognitive decline, which was partially mediated through global Alzheimer’s disease pathology. Building on this work, this study investigated mediation by β‐amyloid and tau pathology (reflecting brain maintenance) as well as moderation by early‐ and mid‐life cognitive enrichment (ELCE, MLCE; reflecting cognitive reserve) on cognitive functioning at last visit proximate to death.MethodThere were 1015 community‐based participants (M baseline age = 82.57±6.35) from the Rush Memory and Aging Project (MAP) and Minority Aging Research Study (MARS) cohorts, who completed annual cognitive and clinical assessments. ELCE and MLCE composite measures were derived from z‐scored self‐reported indicators obtained at baseline (Table 1). Summary measures of β‐amyloid and tau burden were derived from immunohistochemistry at autopsy. Late‐life cognition was measured using a global composite of 19 z‐scored neuropsychological tests obtained at last visit. To test for cognitive reserve, separate linear regression models examined whether ELCE and MLCE moderated relations between β‐amyloid or tau and cognition, adjusted for age at death and sex. To test for brain maintenance, a series of mediation analyses examined whether β‐amyloid and/or tau burden mediated the relationship of ELCE and MLCE with cognition.ResultELCE (p = .005) and MLCE (p = .005) moderated the relationship between tau—but not β‐amyloid—and late‐life cognition proximate to death (Figure 1). Mediation analyses revealed an indirect effect of β‐amyloid—but not tau—on the relation between ELCE (B = 0.058, p = .004) and MLCE (B = 0.040, p = .03) and late‐life cognition (Figure 2).ConclusionELCE and MLCE improve late‐life cognition partially through reducing β‐amyloid, but not tau, accumulation (i.e., brain maintenance). In contrast, ELCE and MLCE are protective against late‐life cognitive impairment in the presence of tau pathology (i.e., cognitive reserve), but not β‐amyloid.

Life’s Simple 7 Relates to Better Cognitive and Brain Health in Individuals with Autosomal Dominant Frontotemporal Dementia

AbstractBackgroundCardiovascular health plays an important role in brain aging; yet its role in development of autosomal dominant forms of dementia and frontotemporal dementia (FTD) has not been fully elucidated. Life’s Simple 7 (LS7) is a metric of cardiovascular health associated with reduced dementia risk and may represent a transdiagnostic heuristic to promote brain health. We examined the extent to which baseline LS7 associated with cognitive and brain aging trajectories in individuals with genetic FTD.Method243 adults carrying autosomal dominant genetic mutations for FTD and 189 non‐carriers completed neuroimaging, neuropsychological testing, and medical interviews. LS7 at baseline was computed following established procedures based on physical activity, diet, body mass index, smoking, hypertension, diabetes, and hypercholesterolemia; higher scores indicate more optimal cardiovascular health. We examined interactions between baseline LS7 and mutation carrier status on cognitive and brain structural outcomes at baseline (via linear regression) and longitudinally (via linear mixed‐effects models). All models adjusted for baseline age, sex, and education, and CDR®+NACC FTLD.ResultMutation carriers and non‐carriers did not significantly differ on baseline LS7 (t = ‐1.42, p = 0.156). At baseline, there were significant interactions between LS7 and carrier status on frontotemporal (FTL) volume and executive functioning (all p‐values<0.046), such that positive associations between LS7 and neurobehavioral outcomes were stronger among mutation carriers versus noncarriers. Longitudinally, there was also a significant interaction between carrier status and baseline LS7 on memory over time (b = 0.04,p = 0.035) and the interaction approached significance for language trajectories (b = 0.03,p = 0.079); again, the association between higher LS7 and slower cognitive decline was stronger among mutation carriers versus noncarriers, even when excluding symptomatic carriers (b = 0.04,p = 0.047). Among mutation carriers only, higher baseline LS7 related to slower memory (b = 0.04,p = 0.006) and language declines over time (b = 0.044,p = 0.004), but did not significantly relate to FTL volume (b = ‐0.01,p = 0.307) or executive functioning trajectories (b = 0.004,p = 0.913)ConclusionBetter cardiovascular health relates to larger baseline frontotemporal volume and slower cognitive decline in individuals with autosomal dominant FTD. Interaction models suggested the degree to which cardiovascular health associates with better neurobehavioral outcomes is stronger in mutation carriers. Optimizing cardiovascular health may be a particularly important, modifiable approach to mitigate the symptoms associated with pathogenic variants of FTD.

Developing Topics.

Education and gender are well-known predictors of cognitive functioning after age 60, but multiple mechanisms underlie these associations. Research on dementia prevalence in the United States has highlighted the importance of considering historical changes in the quantity (years) of childhood education in potentially delaying diagnosis. Less attention has been given to gender differences in post-secondary education despite considerable increases since the 1970s in the completion of university degrees by women. We examined new data for two cohorts of men and women in the Health and Retirement Study (HRS) about the types and content (field of study) of their college degrees. College information was collected in a Life History Mail Survey (2015-2017). Cognitive status was assessed on a 27-point scale in tests conducted in contingent biennial interviews (2016, 2018). Test scores were classified to indicate normal function, cognitive impairment (MCI / CIND) or dementia based on the validated HRS Langa-Weir algorithm. The analytic sample of 9213 (60% women; 40% men) with complete data included individuals born before 1948 (n = 4662; mean age at cognitive test = 79; age range 69-107) and Baby Boomers born 1948 to 1959 (n = 4551; mean age at cognitive test = 62). As expected, compared to the older cohorts, more Baby Boomers had post-secondary education (44% vs 52%; p <.001). Men in the older cohort were more likely to have a Bachelor or higher-level degree than women, but gender was not a significant predictor of degree type in the Baby Boomers. Cohort disaggregated analyses predicting cognitive function revealed that having a BA/BSc degree provided more protection against cognitive impairment for Baby Boomer women than for men with the same degree (p < .001). College majors were gendered and significantly accounted for variance in late-life cognitive status depending on specialization. The birth cohort and gender disparities in post-secondary education revealed in our analyses provide new insight into modifiable aspects of education beyond childhood. Future research should consider the quality and timing of college education and subsequent employment histories as life course factors that differentiate trajectories of cognitive aging and transition to dementia.

18 Vascular Risk, Cerebral White Matter, and Executive Functioning in Vietnam-Era Veterans with Traumatic Brain Injury and/or Post-Traumatic Stress Disorder: A Department of Defense Alzheimer’s Disease Initiative (DoD-ADNI) Study

Objective:Research indicates that Veterans with a history of traumatic brain injury (TBI) are at increased risk for dementia. Although the precise mechanisms underlying this relationship are poorly understood, remote TBI may exacerbate normal age-related changes to cerebral white matter (WM) and result in cognitive decline. However, Veterans commonly experience a constellation of mental (e.g., post-traumatic stress disorder [PTSD] and depression) and vascular (e.g., diabetes, hypertension, obesity) health conditions that have also been implicated in pathologic cerebral WM and cognitive aging trajectories. Therefore, the present study sought to (1) clarify the effects of remote TBI within the context of PTSD, depression, and vascular risk on WM micro- and macrostructure, and (2) explore if WM integrity is associated with cognition in a sample of Vietnam-Era Veterans.Participants and Methods:The sample consisted of 195 male Veterans ages 60-80 (mean age=69.3) enrolled in the Department of Defense-Alzheimer’s Disease Neuroimaging Initiative (DoD-ADNI) study. 102 Veterans met criteria for TBI by sustaining a head-injury that resulted in a loss of consciousness, alteration of consciousness, or post-traumatic amnesia. Current and/or lifetime PTSD was designated by scores &gt;30 on the Clinician-Administered PTSD Scale. The Geriatric Depression Scale was used as a continuous measure of depression. A vascular risk score (0-3) was calculated based on diabetes, hypertension, and obesity (BMI &gt;30 kg/m2). An executive functioning composite was created by averaging sample-specific z-scores for Trail Making Tests (A and B), with higher scores indicating worse performance. Voxelwise analysis of WM microstructure (fractional anisotropy [FA]) was conducted with Tract-Based Spatial Statistics (TBSS), using non-parametric permutation testing with threshold-free cluster enhancement. SPM’s Lesion Segmentation Tool was used to investigate WM macrostructure (WM hyperintensity [WMH] volume). Lesion probability maps were masked to restrict WMH volume calculations to WM. Robust regression using M-estimation and predictive R2 calculated using 10-fold cross-validation examined WMH volume, predictor, and cognitive associations. Age was a covariate in all WM analyses, and education was a covariate in all cognitive analyses.Results:TBSS analysis revealed widespread, significant negative relationships between vascular risk and FA across numerous WM tracts (p’s&lt;0.05). These associations remained significant after adjusting for TBI history, PTSD, and depression. TBSS identified significant positive relationships between executive functioning performance and FA across similar brain regions (p’s&lt;0.05). Robust regressions revealed that vascular risk significantly predicted WMH volume (p=0.006; ß=0.161; R2=0.093), whereas TBI history, PTSD, and depression did not (p’s=0.107-0.166; ß's=-0.089-0.101). WMH volume significantly predicted executive functioning (p=0.002; ß=0.216; R2=0.105), whereas TBI history, PTSD, depression, and vascular risk did not (p’s=0.123-0.888; ß's=-0.012-0.125).Conclusions:Our results suggest that vascular health, relative to remote TBI, PTSD, and depression, may be more robustly associated with cerebral WM micro- and macrostructure in older Veterans. Furthermore, poorer WM integrity is associated with poorer cognitive performance. These findings underscore the importance of vascular health interventions in preventing negative brain and cognitive aging outcomes in Veterans, independent of TBI history. Future studies might leverage other neuroimaging modalities (e.g., functional MRI) to further investigate the effects of vascular health on aging in Veterans with a history of TBI.

Differential behavioral aging trajectories according to body size, expected lifespan, and head shape in dogs.

The twofold life expectancy difference between dog breeds predicts differential behavioral and cognitive aging patterns between short- and long-lived dogs. To investigate this prediction, we conducted a cross-sectional analysis using survey data from over 15,000 dogs. We examined the effect of expected lifespan and three related factors (body size, head shape, and purebred status) on the age trajectory of various behavioral characteristics and the prevalence of canine cognitive dysfunction (CCD). Our findings reveal that, although age-related decline in most behavioral characteristics began around 10.5years of age, the proportion of dogs considered "old" by their owners began to increase uniformly around 6years of age. From the investigated factors, only body size had a systematic, although not gradual, impact on the aging trajectories of all behavioral characteristics. Dogs weighing over 30kg exhibited an earlier onset of decline by 2-3years and a slower rate of decline compared to smaller dogs, probably as a byproduct of their faster age-related physical decline. Larger sized dogs also showed a lower prevalence of CCD risk in their oldest age group, whereas smaller-sized dogs, dolichocephalic breeds, and purebreds had a higher CCD risk prevalence. The identification of differential behavioral and cognitive aging trajectories across dog groups, and the observed associations between body size and the onset, rate, and degree of cognitive decline in dogs have significant translational implications for human aging research, providing valuable insights into the interplay between morphology, physiological ageing, and cognitive decline, and unravelling the trade-off between longevity and relative healthspan.

Sex- and APOE-specific genetic risk factors for late-onset Alzheimer's disease: Evidence from gene-gene interaction of longevity-related loci.

Advanced age is the largest risk factor for late-onset Alzheimer's disease (LOAD), a disease in which susceptibility correlates to almost all hallmarks of aging. Shared genetic signatures between LOAD and longevity were frequently hypothesized, likely characterized by distinctive epistatic and pleiotropic interactions. Here, we applied a multidimensional reduction approach to detect gene-gene interactions affecting LOAD in a large dataset of genomic variants harbored by genes in the insulin/IGF1 signaling, DNA repair, and oxidative stress pathways, previously investigated in human longevity. The dataset was generated from a collection of publicly available Genome Wide Association Studies, comprising a total of 2,469 gene variants genotyped in 20,766 subjects of Northwestern European ancestry (11,038 LOAD cases and 9,728 controls). The stratified analysis according to APOE*4 status and sex corroborated evidence that pathways leading to longevity also contribute to LOAD. Among the significantly interacting genes, PTPN1, TXNRD1, and IGF1R were already found enriched in gene-gene interactions affecting survival to old age. Furthermore, interacting variants associated with LOAD in a sex- and APOE-specific way. Indeed, while in APOE*4 female carriers we found several inter-pathway interactions, no significant epistasis was found in APOE*4 negative females; conversely, in males, significant intra- and inter-pathways epistasis emerged according to APOE*4 status. These findings suggest that interactions of risk factors may drive different trajectories of cognitive aging. Beyond helping to disentangle the genetic architecture of LOAD, such knowledge may improve precision in predicting the risk of dementia and enable effective sex- and APOE-stratified preventive and therapeutic interventions for LOAD.

Evidence accumulation rate moderates the relationship between enriched environment exposure and age-related response speed declines.

Older adults exposed to enriched environments (EE) maintain relatively higher levels of cognitive function, even in the face of compromised markers of brain health. Response speed (RS) is often used as a simple proxy to measure the preservation of global cognitive function in older adults. However, it is unknown which specific selection, decision, and/or motor processes provide the most specific indices of neurocognitive health. Here, using a simple decision task with electroencephalography (EEG), we found that the efficiency with which an individual accumulates sensory evidence was a critical determinant of the extent to which RS was preserved in older adults (63% female, 37% male). Moreover, the mitigating influence of EE on age-related RS declines was most pronounced when evidence accumulation rates were shallowest. These results suggest that the phenomenon of cognitive reserve, whereby high EE individuals can better tolerate suboptimal brain health to facilitate the preservation of cognitive function, is not just applicable to neuroanatomical indicators of brain ageing, but can be observed in markers of neurophysiology. Our results suggest that EEG metrics of evidence accumulation may index neurocognitive vulnerability of the ageing brain.SIGNIFICANCE STATEMENT:Response speed in older adults is closely linked with trajectories of cognitive ageing. Here, by recording brain activity while individuals perform a simple computer task, we identify a neural metric which is a critical determinant of response speed. Older adults exposed to greater cognitive and social stimulation throughout a lifetime could maintain faster responding, even when this neural metric was impaired. This work suggests EEG is a useful technique for interrogating how a lifetime of stimulation benefits brain health in ageing.

Life Course Socioeconomic Position and Cognitive Aging Trajectories: A Cross-National Cohort Study in China and England.

Cross-national research on cognitive aging inequality has largely concentrated on Western countries. It is unclear whether socioeconomic position (SEP) has similar effects on cognitive decline in emerging economies. We compared the association between life course SEP and cognitive function trajectories between China and England, the largest nation under state socialism and one of the oldest capitalist countries. This cross-cohort study examined participants aged 50 years and older from the China Health and Retirement Longitudinal Study (n = 12,832) and the English Longitudinal Study of aging (n = 8,875). Cognition z-scores were derived using comparable measures of memory and time orientation on 4 occasions. Life course SEP was self-reported by participants at baseline. Seven- to 8-year trajectories of cognition z-scores were estimated using latent growth curve modeling. Country- and gender-specific associations between childhood/adolescent deprivation, education, material wealth, and home ownership were evaluated in relation to model intercept (baseline level) and linear slope (annual rate of change) of cognition. After multivariable adjustment, education was positively associated with the greatest differences in baseline cognition across country and gender. Education was further linked to a slower rate of cognitive decline (z-score units per year); but compared with those with low education, Chinese men (b = 0.032) and women (b = 0.065) with high education had significantly slower declines than English men (b = -0.004) and women (b = 0.010) with high education. Despite substantial between-cohort differences in downstream and upstream determinants of dementia, education provided the greatest benefits to cognitive aging in England but particularly in China.

An Early and Unequal Decline: Life Course Trajectories of Cognitive Aging in the United States.

Objectives: Cognitive aging is a lifelong process with implications for Alzheimer's disease and dementia. This study aims to fill major gaps in research on the natural history of and social disparities in aging-related cognitive decline over the life span. Methods: We conducted integrative data analysis of four large U.S. population-based longitudinal studies of individuals aged 12 to 105 followed over two decades and modeled age trajectories of cognitive function in multiple domains. Results: We found evidence for the onset of cognitive decline in the 4th decade of life, varying gender differences with age, and persistent disadvantage among non-Hispanic Blacks, Hispanics, and those without college education. We further found improvement in cognitive function across 20th century birth cohorts but widening social inequalities in more recent cohorts. Discussion: These findings advance an understanding of early life origins of dementia risk and invite future research on strategies for promoting cognitive health for all Americans.

Cognitive Aging in Older Breast Cancer Survivors.

Cancer and cancer treatments may affect aging processes, altering the trajectory of cognitive aging, but the extant studies are limited in their intervals of assessment (two-five years). We studied the cognitive performance of a cohort of survivors and controls aged from 60 to 89 years utilizing cross-sectional cognitive performance data as an indicator of potential aging trajectories and contrasted these trends with longitudinal data collected over two years. Female breast cancer survivors who had been diagnosed and treated at age 60 or older and were 5- to 15-year survivors (N = 328) and non-cancer controls (N = 158) were assessed at enrollment and at 8, 16, and 24 months with standard neuropsychological tests and comprehensive geriatric assessment. A cross-sectional baseline analysis found the expected inverse association of age with cognition in both groups, with survivors performing lower overall than controls in learning and memory (LM). Younger survivors, i.e., those under 75 years of age, exhibited lower performance in both LM and attention, and processing speed and executive function (APE), compared to controls, with no differences being observed between older survivors and controls, which tracked with deficit accumulation trends. Cognitive differences between the survivors and controls for the LM and APE domains were prominent in younger survivors, as was deficit accumulation, suggesting a mediating effect on cognition. Deficit accumulation may represent a modifiable risk factor in cancer survivorship that may be targeted for prevention and intervention.

Sex Differences in Longitudinal Trajectories of Cognitive Aging in Zaragoza, Spain

ObjectivesThe objective of this study was to document the longitudinal trajectories of cognitive aging in a sample of cognitively healthy subjects of 55 years or older. The following differences between men and women were hypothesized: 1) in the cognitive loss through aging, 2) in the distinct trajectories identified; and 3) in the predictors associated with the identified trajectories. Design and settingA 4-wave, population-based study in Zaragoza, Spain (1994–2006). ParticipantsA total of 2,403 individuals aged 55+ years, cognitively healthy at baseline. MeasurementsAll participants had at least three measurements with the Mini-Mental State Examination (MMSE). Validated Spanish versions of international instruments were used for assessment. Random effects linear panel regression model for analyzing differences by sex in MMSE scores through aging were performed, and growth mixture models (GMM) applied independently for each sex for modeling the longitudinal cognitive trajectories. ResultsWomen showed lower mean MMSE scores in all phases and significantly higher loss in the MMSE from phases 2 to 3 and 3 to 4. The best fitting age-adjusted model of the cognitive trajectories was a 4-class GMM in men and a 3-class in women. Education was a predictor of cognitive trajectories in both men and women. Dependence on iADLs and alcohol status were predictors only for men, and depression and diabetes only for women. ConclusionsThe identified differences by sex in cognitive trajectories and their associated factors suggest that men and women may require a different strategy when addressing cognitive aging.

My Parent, Myself, or My Child: Whose Education Matters Most for Trajectories of Cognitive Aging in Middle Age?

The growing body of evidence linking intergenerational education and late-life cognitive decline is almost exclusively from high-income countries, despite rapid intergenerational changes in education in low- and middle-income countries (LMICs). We used data from the Mexican Health and Aging Study (n=8,822), a cohort study of Mexican adults aged ≥50 years (2001-2018), to evaluate whether parental education (none vs. any formal schooling), one's own education (less than primary school vs. completion of primary school), or an adult child's education (less than high school vs. completion of high school) was associated with verbal memory z scores. We used linear mixed models with inverse probability of attrition weights. Educational attainment in all 3 generations was associated with baseline verbal memory scores, independent of the prior generation's education. Lower parental (β=-0.005, 95% confidence interval: -0.009, -0.002) and respondent (β=-0.013, 95% confidence interval: -0.017, -0.010) educational level were associated with faster decline in delayed (but not immediate) verbal memory z scores. Associations between adult child's education and respondent's verbal memory decline varied by exposure specification. The educational attainment of parents and adult children may influence the cognitive aging of middle-aged and older adults in LMICs. These results have important implications given recent structural shifts in educational attainment in many LMICs.