Modeling cognitive trajectories within longitudinal studies: a focus on older adults

A Subtype Perspective on Cognitive Trajectories in Healthy Aging

Cognitive aging is a complex and dynamic process characterized by changes due to genetics and environmental factors, including lifestyle choices and environmental exposure, which contribute to the heterogeneity observed in cognitive outcomes. This heterogeneity is particularly pronounced among older adults, with some individuals maintaining stable cognitive function while others experience complex, non-linear changes, making it difficult to identify meaningful decline accurately. Current research methods range from population-level modeling to individual-specific assessments. In this work, we review these methodologies and propose that population subtyping should be considered as a viable alternative. This approach relies on early individual-specific detection methods that can lead to an improved understanding of changes in individual cognitive trajectories. The improved understanding of cognitive trajectories through population subtyping can lead to the identification of meaningful changes and the determination of timely, effective interventions. This approach can aid in informing policy decisions and in developing targeted interventions that promote cognitive health, ultimately contributing to a more personalized understanding of the aging process within society and reducing the burden on healthcare systems.

Latent trajectories of recent and delayed memory and their predictors: evidence from SHARE

OBJECTIVES

Cognitive decline is common in the old age, but some evidence suggests it may already occur during adulthood. Previous studies have linked age, gender, educational attainment, depression, physical activity, and social engagement to better cognitive performance over time. However, most studies have used global measures of cognition, which could mask subtle changes in specific cognitive domains. The aim of this study is to examine trajectories of recent and delayed memory recall from a variable-centered perspective, in order to elucidate the impact of age, gender, educational attainment, depression, physical activity, and social engagement on recent and delayed memory both at initial time and across a 10-year period.

DESIGN AND PARTICIPANTS

The sample was formed by 56,616 adults and older adults that participated in waves 4 to 8 of the Survey of Health, Aging and Retirement in Europe (SHARE).

ANALYSES

We used latent growth modeling to establish latent recent and delayed memory trajectories, and then tested the effects of the aforementioned covariates on the latent intercept and slopes.

RESULTS

Results showed that both recent and delayed recall display a quadratic trajectory of decline. All covariates significantly explained initial levels of immediate and delayed recall, but only a few had statistically significant effects on the slope terms.

CONCLUSIONS

We discuss differences between present results and those previously reported in studies using a person-centered approach. This study provides evidence of memory decline during adulthood and old adulthood. Further, results provide support for the neural compensation reserve theory.

Natural vs. Surgical Postmenopause and Psychological Symptoms Confound the Effect of Menopause on Executive Functioning Domains of Cognitive Experience

Objective

The menopause transition is associated with difficulties in executive function. However, it is unclear whether these difficulties persist past perimenopause. This study investigated whether potential confounders, including natural vs. surgical postmenopause and menopause-related psychological symptoms, influence whether executive dysfunction persists into postmenopause.

Study Design

A cross-sectional sample of women aged 35-65 years (N = 1971) in one of four groups, premenopause, perimenopause, natural postmenopause, and surgical postmenopause, were surveyed. Participants self-reported executive functioning with the Brown Attention Deficit Disorder Scale (BADDS), anxiety symptom severity with the Generalized Anxiety Disorder Questionnaire (GAD-7), and depression symptom severity with the Center for Epidemiologic Studies Depression Scale (CES-D).

Main Outcome Measures

We analyzed the association between group and BADDS scores using linear regression models - first, by controlling for age, education, and self-reported attention deficit hyperactivity disorder (ADHD) diagnosis (Model #1) and, second, by further controlling for current difficulty sleeping, anxiety, and depression (Model #2).

Results

In both models, BADDS scores were significantly elevated (indicating more difficulties in executive function) among women in the perimenopausal and surgical postmenopausal groups compared with those in the premenopausal group. Likewise, the perimenopausal and surgical postmenopausal groups had the highest proportions of participants who reported difficulty sleeping and clinical levels of anxiety and depression. BADDS scores were significantly higher in natural postmenopausal vs. premenopausal women without controlling for difficulty sleeping, anxiety, and depression (Model #1), but not when adjusting for these variables (Model #2).

Conclusions

The type of menopause and psychological symptoms are important confounders of the relationship between the menopause transition and executive dysfunction, and help explain whether executive dysfunction persists or recovers in postmenopause.Reprinted from Maturitas 2023; 170:64-73, with permission from Elsevier. Copyright © 2023.

Hemoglobin A1c Serum Level Predicts 5-year Mortality in Patients with Cognitive Impairment

Background

Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) may occur as preclinical stages of Alzheimer's disease (AD), ultimately leading to dementia. Glycated hemoglobin A1c (HbA1c) is a diagnostic marker for diabetes mellitus and indicates mortality risk.

Objectives

This university-based, exploratory retrospective study examined the impact of HbA1c serum level on 5-year mortality among individuals with cognitive impairment.

Methods

Included were 1076 subjects aged at least 50 years who visited the Memory Outpatient Clinic of the Medical University of Vienna due to memory problems. Participants were diagnosed with SCD, MCI, or AD subsequent to neurological examination, standard laboratory blood tests, and neuropsychological testing. Survival was compared between diagnostic subgroups and with respect to HbA1c categories using log-rank tests based on Kaplan-Meier functions. The Neuropsychological Test Battery Vienna (NTBV) was dimensionally reduced, and a principal component analysis (PCA) was performed to further analyze results. Corresponding factor scores, HbA1c values, and baseline characteristics were included in Cox proportional hazards models to assess 5-year mortality risk.

Results

During the observation period, 323 patients (30%) died at a mean age comparable between diagnostic subgroups (SCD 84.2 ± 10.1, MCI 81.2 ± 8.3, AD 82.2 ± 7.4 years). Individuals with normal serum HbA1c levels had significant advantages in survival within the MCI (12.9 ± .3 vs. 10.0 ± .8 years) and the AD subgroups (8.2 ± .4 vs. 5.5 ± .6 years), and metric HbA1c predicted 5-year mortality (HR 1.24).

Conclusion

This study demonstrates an association between abnormal HbA1c serum levels and increased mortality.

Neural network process simulations support a distributed memory system and aid design of a novel computer adaptive digital memory test for preclinical and prodromal Alzheimer's disease

OBJECTIVE

Growing evidence supports the importance of learning as a central deficit in preclinical/prodromal Alzheimer's disease. The aims of this study were to conduct a series of neural network simulations to develop a functional understanding of a distributed, nonmodular memory system that can learn efficiently without interference. This understanding is applied to the development of a novel digital memory test.

METHOD

Simulations using traditional feed forward neural network architectures to learn simple logic problems are presented. The simulations demonstrate three limitations: (a) inefficiency, (b) an inability to learn problems consistently, and (c) catastrophic interference when given multiple problems. A new mirrored cascaded architecture is introduced to address these limitations, with support provided by a series of simulations.

RESULTS

The mirrored cascaded architecture demonstrates efficient and consistent learning relative to feed forward networks but also suffers from catastrophic interference. Addition of context values to add the capability of distinguishing features as part of learning eliminates the problem of interference in the mirrored cascaded, but not the feed forward, architectures.

CONCLUSIONS

A mirrored cascaded architecture addresses the limitations of traditional feed forward neural networks, provides support for a distributed memory system, and emphasizes the importance of context to avoid interference. These process models contributed to the design of a digital computer-adaptive word list learning test that places maximum stress on the capability to distinguish specific episodes of learning. Process simulations provide a useful method of testing models of brain function and contribute to new approaches to neuropsychological assessment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Natural vs. surgical postmenopause and psychological symptoms confound the effect of menopause on executive functioning domains of cognitive experience

OBJECTIVE

The menopause transition is associated with difficulties in executive function. However, it is unclear whether these difficulties persist past perimenopause. This study investigated whether potential confounders, including natural vs. surgical postmenopause and menopause-related psychological symptoms, influence whether executive dysfunction persists into postmenopause.

STUDY DESIGN

A cross-sectional sample of women aged 35-65 years (N = 1971) in one of four groups, premenopause, perimenopause, natural postmenopause, and surgical postmenopause, were surveyed. Participants self-reported executive functioning with the Brown Attention Deficit Disorder Scale (BADDS), anxiety symptom severity with the Generalized Anxiety Disorder Questionnaire (GAD-7), and depression symptom severity with the Center for Epidemiologic Studies Depression Scale (CESD).

MAIN OUTCOME MEASURES

We analyzed the association between group and BADDS scores using linear regression models - first, by controlling for age, education, and self-reported attention deficit hyperactivity disorder (ADHD) diagnosis (Model #1) and, second, by further controlling for current difficulty sleeping, anxiety, and depression (Model #2).

RESULTS

In both models, BADDS scores were significantly elevated (indicating more difficulties in executive function) among women in the perimenopausal and surgical postmenopausal groups compared with those in the premenopausal group. Likewise, the perimenopausal and surgical postmenopausal groups had the highest proportions of participants who reported difficulty sleeping and clinical levels of anxiety and depression. BADDS scores were significantly higher in natural postmenopausal vs. premenopausal women without controlling for difficulty sleeping, anxiety, and depression (Model #1), but not when adjusting for these variables (Model #2).

CONCLUSIONS

The type of menopause and psychological symptoms are important confounders of the relationship between the menopause transition and executive dysfunction, and help explain whether executive dysfunction persists or recovers in postmenopause.

Socioeconomic Status, Race/Ethnicity, and Unexpected Variation in Dementia Classification in Longitudinal Survey Data

OBJECTIVES

As dementia affects a growing number of older adults, it is important to understand its detection and progression. We identified patterns in dementia classification over time using a longitudinal, nationally representative sample of older adults. We examined the relationship between socioeconomic status and race/ethnicity, and patterns in dementia classification.

METHODS

Data for 7,218 Medicare beneficiaries from the 2011-2017 National Health and Aging Trends Study (NHATS) were classified into five categories: consistently no dementia, consistently cognitive impairment, "typical" dementia progression, "expected" variation, and "unexpected" variation. Multivariable multinomial logistic regression assessed relative risk of dementia classification by sociodemographic and health factors.

RESULTS

Among NHATS respondents, 59.5% consistently were recorded as having no dementia, 7% consistently cognitively impaired, 13% as having typical progression, 15% as having expected variation, and 5.5% as having unexpected variation. In multivariable models, compared with consistent dementia classification, less education, Medicare-Medicaid-dual enrollment, and identifying as non-Hispanic Black were associated with increased likelihood of unexpected variation (e.g., non-Hispanic Black adjusted risk ratio: 2.12, 95% CI: 1.61-2.78, p < .0001).

DISCUSSION

A significant minority of individuals have unexpected patterns of dementia classification over time, particularly individuals with low socioeconomic status and identifying as non-Hispanic Black. Dementia classification uncertainty may make it challenging to activate resources (e.g., health care, caregiving) for effective disease management, underscoring the need to support persons from at-risk groups and to carefully evaluate cognitive assessment tools to ensure they are equally reliable across groups to avoid magnifying disparities.

Can cochlear implantation prevent cognitive decline in the long-term follow-up?

Cognitive function and hearing are known to both decline in older adults. As hearing loss is proposed to be one modifiable risk factor for dementia, the impact of auditory rehabilitation on cognitive decline has been gaining increasing attention. Despite a large number of studies, long-term data are still rare. In a large prospective longitudinal monocentric study, 50 adults (aged ≥ 50 years) with severe postlingual bilateral hearing loss received a cochlear implant (CI). They underwent comprehensive neurocognitive testing prior to implantation (T1), at 12 months (T2) and up to 65 months (T3) after implantation. Various cognitive subdomains such as attention, inhibition, working memory, verbal fluency, mental flexibility and (delayed) recall were assessed by the computer-based non-auditory test battery ALAcog©. The observed trajectories of two exemplary cognitive subdomains (delayed recall and working memory) were then fitted over time using multilevel growth models to adjust for sociodemographic covariates and compared with 5-year longitudinal data from a sample of older adults from the representative Survey of Health, Aging and Retirement in Europe (SHARE) study. Postoperatively, auditory functions improved from 6.98% (SD 12.83) to 57.29% (SD 20.18) in monosyllabic speech understanding. Cognitive functions significantly increased from T1 to T3 in attention (p = 0.001), delayed recall (p = 0.001), working memory (OSPAN; p = 0.001), verbal fluency (p = 0.004), and inhibition (p = 0.002). A closer look at follow-up revealed that cognitive improvement could be detected between T1 and T2 and thereafter remained stable in all subtests (p ≥ 0.06). Additional longitudinal analysis confirmed these findings in a rigorous multilevel approach in two exemplary cognitive subdomains. In contrast to the SHARE data, there was no evidence for age-differential associations over time in CI recipients. This suggests that older adults benefit equally from cochlear implantation. CI users with worse preoperative cognitive skills experienced the most benefit (p < 0.0001). Auditory rehabilitation by cochlear implantation has a stimulating effect on cognitive functions beyond an improvement in speech understanding and an increased well-being. Large multicenter studies using standardized protocols have to be undertaken in the future to find out whether hearing restoration might help to prevent cognitive decline.

Dyadic Links Between Health Changes and Well-Being: The Role of Non-Spousal Confidants

Although the marital relationship is often the primary source of emotional support in adulthood, sole reliance on the spouse to discuss health-related issues may be harmful to the well-being of both partners. The first aim of this study was to examine whether declines in health during later life would be associated with poorer psychological well-being in self and partner. We further investigated whether declining health would have a stronger impact on own and partner psychological well-being in the absence of non-spousal health confidants. Longitudinal actor-partner interdependence models (APIMs) were used to test both hypotheses with dyadic data from Wave 2 (2010-2011) and Wave 3 (2015-2016) of the National Social Life, Health, and Aging Project (NSHAP). Contrary to prediction, increased anxiety following spousal declines in gait speed and cognitive function occurred for those whose spouse did (rather than did not) have additional health confidants. A much fuller understanding is needed in regard to whether close relationships provide resources or present unwanted complications to dyadic coping, and the processes by which effects occur.

The Associations of Meteorological and Environmental Factors with Memory Function of the Older Age in Urban Areas

Individual, meteorological, and environmental factors are associated with cognitive function in older age. However, little is known about how meteorological and environmental factors interact with individual factors in affecting cognitive function in older adults. In the current study, we used mixed effects models to assess the association of individual, meteorological, and environmental factors with cognitive function among older adults in urban areas. Data from 2623 adults aged 60 to 91 years from 25 provinces (or autonomous regions/municipalities) from the China Family Panel Studies (CFPS) were used. We used the memory test in CFPS to measure memory function, while meteorological data from the daily climate data set of China’s surface international exchange stations, and the traffic and greening data compiled by the National Bureau of Statistics (NBS) of China, were used to assess meteorological and environmental factors. The ICC of the empty model indicated that 7.7% of the variation in memory test scores for the older adults was caused by provincial characteristics. Results showed that the temperature and relative humidity of provinces moderated the effect of gender on the memory function for the older urban adults. Specifically, in the high temperature areas, memory scores for females were higher than those of males, and in the middle humidity areas, memory scores were also higher for the females than those of males. This study explained how meteorological and environmental factors played roles in influencing demographic factors on memory function among older adults. Further research is needed to better define the role and potential mechanism of this moderation.

Cognition in Healthy Aging

The study of cognitive change across a life span, both in pathological and healthy samples, has been heavily influenced by developments in cognitive psychology as a theoretical paradigm, neuropsychology and other bio-medical fields; this alongside the increase in new longitudinal and cohort designs, complemented in the last decades by the evaluation of experimental interventions. Here, a review of aging databases was conducted, looking for the most relevant studies carried out on cognitive functioning in healthy older adults. The aim was to review not only longitudinal, cross-sectional or cohort studies, but also by intervention program evaluations. The most important studies, searching for long-term patterns of stability and change of cognitive measures across a life span and in old age, have shown a great range of inter-individual variability in cognitive functioning changes attributed to age. Furthermore, intellectual functioning in healthy individuals seems to decline rather late in life, if ever, as shown in longitudinal studies where age-related decline of cognitive functioning occurs later in life than indicated by cross-sectional studies. The longitudinal evidence and experimental trials have shown the benefits of aerobic physical exercise and an intellectually engaged lifestyle, suggesting that bio-psycho-socioenvironmental factors concurrently with age predict or determine both positive or negative change or stability in cognition in later life.

Mild and moderate cognitive impairment and mortality among Brazilian older adults in long-term follow-up: The Bambui Health Aging Study

Objective:

To compare mortality in older adults with and without mild or moderate cognitive impairment over 15 years of follow-up in a middle-income country, where little information on this subject is available.

Methods:

A total of 1,281 community-dwelling older adults were followed-up for a median of 13.3 years. We evaluated their cognitive impairment using the Mini-Mental State Examination, categorizing it as none (1.0 SD above cutoff means), mild (1.0 SD below cutoff means) or moderate (2.0 SD below cutoff means). The date of death was determined by reviewing death certificates. Cox’s proportional hazards models were used to evaluate the risk of mortality in participants with cognitive impairment.

Results:

Participants with mild or moderate cognitive impairment had a higher mortality risk than those without it in the unadjusted model, but these associations did not remain in the final model. After sex stratification, only men with moderate cognitive impairment had a higher mortality risk in the final model.

Conclusion:

The findings suggest an association between moderate cognitive impairment and all-cause mortality in men in a large Brazilian cohort of older adults.

Normative Cognitive Decline in Old Age

OBJECTIVE

To characterize trajectories of normative cognitive aging.

METHODS

Older persons without dementia at study enrollment (n = 1,010) had annual cognitive testing for up to 24 years (mean = 9.9 years, standard deviation = 5.0), died, and underwent a neuropathologic examination to quantify 9 postmortem markers of common neurodegenerative and cerebrovascular conditions. To accommodate the heterogeneity in cognitive trajectories, we used functional mixed effects models, which allow individuals to have different patterns of cognitive decline under a unified model structure.

RESULTS

In a functional mixed effects model, postmortem markers (Alzheimer disease pathology, Lewy bodies, transactive response DNA-binding protein 43 pathology, hippocampal sclerosis, atherosclerosis, gross infarcts) were associated with global cognitive decline. Residual global cognitive decline after adjustment for neuropathologic burden was weakly related to age at death; it occurred in only about one-third of participants, mostly proximate to death. Results were comparable after eliminating the initial cognitive assessments to minimize retest learning or controlling for frailty proximate to death. Analyses were also conducted with composite measures of episodic memory and perceptual speed. Residual decline not attributable to neuropathologic burden was confined to a subset for each outcome and was most evident proximate to death. Age at death was unrelated to residual decline in episodic memory but was related to residual decline in perceptual speed.

INTERPRETATION

Late life cognitive loss mainly reflects non-normative pathologic and mortality-related processes rather than normative age-related processes. ANN NEUROL 2020;87:816-829.

Functional Status, Cognition, and Social Relationships in Dyadic Perspective

OBJECTIVES

Health limitations can change older adults' social relationships and social engagement. Yet, researchers rarely examine how the disability of one's spouse might affect one's social relationships, even though such life strains are often experienced as a couple. This study investigates the association between functional and cognitive limitations and social experience in a dyadic context.

METHOD

We use actor-partner interdependence models to analyze the partner data from 953 heterosexual couples in Wave II (2010-2011) of the National Social Life, Health, and Aging Project.

RESULTS

One spouse's functional and cognitive health is associated with the other's relationship quality, but the pattern varies by gender. Husbands' functional limitations are associated with lower marital support and higher marital strain in wives, but wives' functional limitations are related to lower family and friendship strain in husbands. Husbands' cognitive impairment also predicts higher family and friend support in wives.

DISCUSSION

Findings support a gendered dyadic relationship between health and social life and highlight women's caregiver role and better connection with family and friends. There are also differences between experiencing cognitive and physical limitations in couples. Finally, mild health impairment sometimes shows stronger effects on social relationships than severe impairment, suggesting adaptation to health transition.

Decline in Memory, Visuospatial Ability, and Crystalized Cognitive Abilities in Older Adults: Normative Aging or Terminal Decline?

The aim of this study is to explore the pattern of change in multiple measures of cognitive abilities in a sample of oldest-old adults, comparing two different time metrics (chronological age and time to death) and therefore examining both underlying conceptual assumptions (age-related change and terminal decline). Moreover, the association with individual characteristics as sex, education, and dementia diagnosis was also examined. Measures of cognitive status (Mini-Mental State Examination and the Swedish Clock Test) and tests of crystallized (knowledge and synonyms), memory (verbal memory, nonverbal long-term memory, recognition and correspondence, and short-term memory), and visuospatial ability were included. The sample consisted of 671 older Swedish adult participants of the OCTO Twin Study. Linear mixed models with random coefficients were used to analyse change patterns and BIC indexes were used to compare models. Results showed that the time to death model was the best option in analyses of change in all the cognitive measures considered (except for the Information Test). A significant cognitive decline over time was found for all variables. Individuals diagnosed with dementia had lower scores at the study entrance and a faster decline. More educated individuals performed better in all the measures of cognition at study entry than those with poorer education, but no differences were found in the rate of change. Differences were found in age, sex, or time to death at baseline across the different measures. These results support the terminal decline hypothesis when compared to models assuming that cognitive changes are driven by normative aging processes.

Measuring cognition: the Chicago Cognitive Function Measure in the National Social Life, Health and Aging Project, Wave 2

OBJECTIVES

To describe the development of a multidimensional test of cognition for the National Social life, Health and Aging Project (NSHAP), the Chicago Cognitive Function Measure (CCFM).

METHOD

CCFM development included 3 steps: (a) A pilot test of the Montreal Cognitive Assessment (MoCA) to create a standard protocol, choose specific items, reorder items, and improve clarity; (b) integration into a CAPI-based format; and (c) evaluation of the performance of the CCFM in the field. The CCFM was subsequently incorporated into NSHAP, Wave 2 (n = 3,377).

RESULTS

The pre-test (n = 120) mean age was 71.35 (SD 8.40); 53% were female, 69% white, and 70% with college or greater education. The MoCA took an average of 15.6min; the time for the CCFM was 12.0 min. CCFM scores (0-20) can be used as a continuous outcome or to adjust for cognition in a multivariable analysis. CCFM scores were highly correlated with MoCA scores (r = .973). Modeling projects MoCA scores from CCFM scores using the equation: MoCA = (1.14 × CCFM) + 6.83. In Wave 2, the overall weighted mean CCFM score was 13.9 (SE 0.13).

DISCUSSION

A survey-based adaptation of the MoCA was successfully integrated into a nationally representative sample of older adults, NSHAP Wave 2.

Maternal education, anthropometric markers of malnutrition and cognitive function (ELSA-Brasil)

Background

The early exposure to poor social and nutritional conditions may influence cognitive function during adult age. However, the relative impact of these factors has not yet been established and they can vary during the course of life.

Methods

Analysis of data from 12,997 participants (35-64 years) of the baseline exams (2008-2010) of the Longitudinal Study of Adult Health (ELSA-Brasil), a cohort of Brazilian civil servants. Four cognitive tests were applied: learning, recall and word recognition; semantic and phonemic verbal fluency; trail-making test version B. The markers of early nutritional and social conditions were maternal educational level, birth weight, and length of trunk and leg. The presence of independent association between every early marker and the poor performance in each cognitive test was investigated by multiple logistic regression, after mutual adjustment and considering the effects of gender, age and participant’s schooling level. The cut off for poor performance was the worst age-specific percentile of the final score distribution for each test.

Results

After full adjustments, lower maternal education increased the chances of poor performance in all cognitive tests, with a dose-response gradient; low birth-weight was related to poor performance in the trail-making test B (OR = 1.63, 95% IC = 1.29-2.06); and greater trunk length decreased the chances of poor performance in the semantic and phonemic verbal fluency (OR = 0.96, 95% IC = 0.94-0.97) and in the trail-making test B (OR = 0.94, 95% IC = 0.92-0.95). Leg length was not associated with any of the tests examined. The associations found were not modified by the educational attainment of the participants.

Conclusions

Early exposure to adverse social and nutritional conditions appear detrimental to semantic memory, learning, concentration, executive control and language among adults, independent of adulthood educational achievement.

APOE ε4, Alzheimer's disease pathology, cerebrovascular disease, and cognitive change over the years prior to death

The goal of this study was to examine the association of the APOE ε4 allele with the late-life cognitive trajectory and test the hypothesis that the association of ε4 with cognitive decline is explained by Alzheimer's disease (AD) neuropathology. Participants (N = 581) came from 2 longitudinal clinical-pathologic studies of aging and dementia, the Religious Orders Study (ROS) and the Memory and Aging Project (MAP). Longitudinal measures of cognition were derived from detailed annual neuropsychological testing. Uniform neuropathologic evaluations provided quantitative measures of AD pathology, chronic cerebral infarctions, and Lewy bodies. Participants with 1 or more copies of the ε4 allele (ε2/4 excluded) were considered ε4 carriers. Random change point models were applied to examine the association of the ε4 allele with onset of terminal decline as well as preterminal and terminal slopes. On average, the onset of terminal decline occurred around 3 years before death, and the rate of terminal decline was eightfold faster than the preterminal decline. The presence of the ε4 allele was associated with an earlier onset of terminal decline and faster rates of decline before and after its onset. After adjusting for AD pathology, the ε4 allele was no longer associated with onset of terminal decline or preterminal slope, and the association with terminal slope became marginal. The APOE ε4 allele is an important determinant of late-life change in cognition, including terminal decline, and works primarily through AD pathology.

Association of crossword puzzle participation with memory decline in persons who develop dementia

Participation in cognitively stimulating leisure activities such as crossword puzzles may delay onset of the memory decline in the preclinical stages of dementia, possibly via its effect on improving cognitive reserve. We followed 488 initially cognitively intact community residing individuals with clinical and cognitive assessments every 12-18 months in the Bronx Aging Study. We assessed the influence of crossword puzzle participation on the onset of accelerated memory decline as measured by the Buschke Selective Reminding Test in 101 individuals who developed incident dementia using a change point model. Crossword puzzle participation at baseline delayed onset of accelerated memory decline by 2.54 years. Inclusion of education or participation in other cognitively stimulating activities did not significantly add to the fit of the model beyond the effect of puzzles. Our findings show that late life crossword puzzle participation, independent of education, was associated with delayed onset of memory decline in persons who developed dementia. Given the wide availability and accessibility of crossword puzzles, their role in preventing cognitive decline should be validated in future clinical trials.