Cognitive decline and literacy among ethnically diverse elders

Stressful Life Events and Racial Disparities in Cognition Among Middle-Aged and Older Adults

BACKGROUND

It is well-documented that African Americans have elevated risk for cognitive impairment and dementia in late life, but reasons for the racial disparities remain unknown. Stress processes have been linked to premature age-related morbidity, including Alzheimer's and related dementias (ADRD), and plausibly contribute to social disparities in cognitive aging.

OBJECTIVE

We examined the relationship between stressful life events and cognitive decline among African American and White participants enrolled in the Wisconsin Registry for Alzheimer's Prevention (WRAP).

METHODS

Linear mixed models including demographic, literacy, and health-related covariates were used to estimate (1) relationships between a life event index score and decline in cognitive test performance in two domains of executive function (Speed & Flexibility, Working Memory) and one domain of episodic memory (Verbal Learning & Memory) among 1,241 WRAP enrollees, stratified by race, and (2) contributions of stressful life events to racial differences in cognition within the full sample.

RESULTS

African Americans (N = 50) reported more stressful life events than Whites (N = 1,191). Higher stress scores associated with poorer Speed & Flexibility performance in both groups, though not with declines across time, and partially explained racial differentials in this domain. Among African Americans only, stressor exposure also associated with age-related decline in Verbal Learning & Memory. Stressor-cognition relationships were independent of literacy and health-related variables.

CONCLUSIONS

Greater lifetime stress predicted poorer later-life cognition, and, in a small sample of African Americans, faster declines in a key domain of episodic memory. These preliminary findings suggest that future work in large minority aging cohorts should explore stress as an important source of modifiable, socially-rooted risk for impairment and ADRD in African Americans, who are disproportionately exposed to adverse experiences across the life course.

The relationship between cognitive reserve and personality traits: a pilot study on a healthy aging Italian sample

BACKGROUND

Exploring the role of different individual factors in affecting the cognitive reserve levels is crucial step for aging research. Several studies explored the relationship between personality traits and aging, but a specific focus on the cognitive reserve is missing.

AIMS

This study aimed at collecting more direct evidence about possible relationships between cognitive reserve and personality traits.

METHODS

A sample of 100 healthy aging participants was involved in the study. They completed the Big Five personality inventory and a test to assess the cognitive reserve.

RESULTS

Results returned a positive relationship between the personality traits and participants' cognitive reserve. The only factor that did not return a significant correlation was Emotional stability (which overlaps with Neuroticism).

DISCUSSION

This study provides additional evidence to the existing literature and also adds relevant information and a critical reading regarding the role of personality traits that has been neglected in the aging literature, Friendliness and Conscientiousness.

CONCLUSION

The ability to measure and identify personality traits could be important in future research for developing interventions or activities that could target specific personality characteristics.

US Migration Status of Adult Children and Cognitive Decline Among Older Parents Who Remain in Mexico

Low- and middle-income countries (LMICs) are experiencing rapid aging, a growing dementia burden, and relatively high rates of out-migration among working-age adults. Family member migration status may be a unique societal determinant of cognitive aging in LMIC settings. We aimed to evaluate the association between adult child US migration status and change in cognitive performance scores using data from the Mexican Health and Aging Study, a population-based, national-level cohort study of Mexico adults aged ≥50 years at baseline (2001), with 2-, 12-, and 14-year follow-up waves (2003, 2012, and 2015). Cognitive performance assessments were completed by 5,972 and 4,939 respondents at 11 years and 14 years of follow-up, respectively. For women, having an adult child in the United States was associated with steeper decline in verbal memory scores (e.g., for 9-year change in immediate verbal recall z score, marginal risk difference (RD) = -0.09 (95% confidence interval (CI): -0.16, -0.03); for delayed verbal recall z score, RD = -0.10 (95% CI: -0.17, -0.03)) and overall cognitive performance (for overall cognitive performance z score, RD = -0.04, 95% CI: -0.07, -0.00). There were mostly null associations for men. To our knowledge, this is the first study to have evaluated the association between family member migration status and cognitive decline; future work should be extended to other LMICs facing population aging.

Family Ties and Aging in a Multiethnic Cohort

Objective: Lack of social support is linked to lower cognitive function and cognitive decline. We investigated the effects of a specific type of social relationship, family ties, on cognitive trajectories in non-Hispanic whites, non-Hispanic blacks, and Hispanics. Methods: Using multiple-group latent growth curve models, we analyzed associations between the number of children/grandchildren/siblings/other relatives contacted within the past month at baseline and cognitive trajectories in 1420 older adults who were nondemented at baseline. Language, memory, and visuospatial abilities were assessed at baseline and at 18- and 24-month follow-ups for up to six visits. Inferential analyses assessed the differential effects of sex/gender and race/ethnicity for each family tie. Results: Independent of all covariates, contact with more relatives was associated with better initial memory (b = .01) and language functioning (b = .01) across race/ethnicity and sex/gender. Conclusion: The size of peripheral rather than immediate family networks may be more likely to affect cognitive function in older adults.

Literacy Mediates Racial Differences in Financial and Healthcare Decision Making in Older Adults

BACKGROUND/OBJECTIVES

Decision making in financial and healthcare matters is of critical importance for well-being in old age. Preliminary work suggests racial differences in decision making; however, the factors that drive racial differences in decision making remain unclear. We hypothesized literacy, particularly financial and health literacy, mediates racial differences in decision making.

DESIGN

Community-based epidemiologic cohort study.

SETTING

Communities in northeastern Illinois.

PARTICIPANTS

Nondemented Black participants (N = 138) of the Rush Alzheimer's Disease Center Minority Aging Research Study and the Rush Memory and Aging Project who completed decision-making and literacy measures were matched to White participants (N = 138) according to age, education, sex, and global cognition using Mahalanobis distance (total N = 276).

MEASUREMENTS

All participants completed clinical assessments, a decision-making measure that resembles real-world materials relevant to finance and healthcare, and a financial and health literacy measure. Regression models were used to examine racial differences in decision making and test the hypothesis that literacy mediates this association. In secondary analyses, we examined the impact of literacy in specific domains of decision making (financial and healthcare).

RESULTS

In models adjusted for age, education, sex, and global cognition, older Black adults performed lower than older White adults on literacy (β = -8.20; SE = 1.34; 95% CI = -10.82 to -5.57; P < .01) and separately on decision making (β = -.80; SE = .23; 95% CI = -1.25 to -.34; P < .01). However, when decision making was regressed on both race and literacy, the association of race was attenuated and became nonsignificant (β = -.45; SE = .24; 95% CI = -.93 to .02; P = .06), but literacy remained significantly associated with decision making (β = .04; SE = .01; 95% CI = .02-.06; P < .01). In secondary models, a similar pattern was observed for both financial and healthcare decision making.

CONCLUSIONS

Racial differences in decision making are largely mediated by literacy. These findings suggest that efforts to improve literacy may help reduce racial differences in decision making and improve health and well-being for diverse populations. J Am Geriatr Soc 68:1279-1285, 2020.

Education and age-related decline in cognitive performance: Systematic review and meta-analysis of longitudinal cohort studies

Central theories of cognitive aging propose that education is an important protective factor for decline in cognitive performance in older age. We conducted a systematic review and meta-analysis of reported estimates of an association between educational attainment and change in performance in six cognitive domains (episodic memory, processing speed, verbal fluency, crystallized intelligence, fluid intelligence, and global ability) in the general population of older individuals. The systematic search (11^th of October 2019) identified 92 eligible articles. The episodic memory domain had the highest number of estimates (37 estimates from 18 articles, n = 109,281) included in the meta-analysis. The fewest estimates (6 estimates from 6 articles, n = 5263) were included for fluid intelligence. Pooled mean estimates from an inverse-variance weighted random effects analysis were not statistically significant and indicated that any association between education and change in cognitive performance is likely of a negligible magnitude. The estimates for education's role (one additional year) for change in cognitive performance ranged from -0.019 (95 % confidence interval, CI = -0.047, 0.010) to 0.004SD (CI = -0.003, 0.012) per decade. Even if the larger positive point estimates (i.e., protective effects) are selectively considered, the influence of education on change is still at least 12 times less important for the cognitive functioning of an older individual than the association between education and level of cognitive performance. Sensitivity analyses did not substantially alter these results. However, heterogeneity was substantial, and remained largely unexplained by mean age, mean educational attainment, Gini coefficient, GDP per capita, maximum follow-up period, and publication year. Overall, education is an important factor in aging due to its robust association with level of performance, but the current base of empirical evidence is not revealing a consistent and substantial association between educational attainment and changes in cognitive performance in the general population. Theories of cognitive aging must be updated to incorporate this pattern of findings.

Age of Migration and Cognitive Function Among Older Latinos in the United States

BACKGROUND

Age of migration has been shown to have a robust association with Latino immigrant health outcomes; however, the relationship between timing of migration and cognition is less understood.

OBJECTIVE

To examine associations between race/ethnicity, nativity, age of migration, and cognitive aging among US-born (USB) non-Latino Whites (NLW) and USB and foreign-born Latinos 50 years and older.

METHODS

We used longitudinal biennial data from the Health and Retirement Study (HRS; 2006-2014) to fit generalized linear and linear latent growth curve models for: 1) global cognition (Modified Telephone Interview for Cognitive Status; TICS-M); 2) memory and attention subdomains of TICS-M; and 3) cognitive dysfunction. We also tested for sex modifications.

RESULTS

In age and sex adjusted models, all Latino subgroups, independent of nativity and age of migration, had lower global and domain-specific cognitive scores and higher propensity of cognitive impairment classification compared to USB-NLWs. Differences between USB Latinos, but not other Latino subgroups, and USB-NLWs remained after full covariate adjustment. Latinas, independent of nativity or age of migration, had poorer cognitive scores relative to NLW females. Differences between all Latinos and USB-NLWs were principally expressed at baseline. Racial/ethnic, nativity, and age of migration grouping was not associated with slope (nor explained variance) of cognitive decline.

CONCLUSION

Older US-born Latinos, regardless of sex exhibit poorer cognitive function than older USB-NLWs and foreign-born Latinos. Social determinants that differentially affect cognitive function, particularly those that compensate for education and sex differences among US-born Latinos and foreign-born Latinos, require further exploration.

Red Cell Distribution Width Is Directly Associated with Poor Cognitive Performance among Nonanemic, Middle-Aged, Urban Adults

BACKGROUND

Epidemiological evidence suggests that both anemia and elevated red cell distribution width (RDW) are associated with cognitive impairment. However, the interplay between these 2 predictors has been understudied.

OBJECTIVES

We examined sex- and anemia-specific associations between RDW and cognitive performance among urban adults in the United States.

METHODS

Data from the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study (Baltimore, MD; participants aged 30-65 y at baseline, ∼59% African-American, 45% men) were used. Participants were selected based on the completion of 11 cognitive tasks at baseline (2004-2009) and follow-up (2009-2013) visits (mean time between visits: 4.64 ± 0.93 y) and availability of exposure and covariate data, yielding a sample of between 1526 and 1646 adults out of the initial 3720 adults recruited at baseline. Multiple linear mixed-effects regression models were conducted with RDW as the main exposure of interest and anemia/sex as the key effect modifiers.

RESULTS

Overall, high RDWs were linked to poorer baseline performance on the California Verbal Learning Test (CVLT) List A (per 1 unit increase in RDW %, main effect: γ01 = -0.369 ± 0.114; P = 0.001) and to slower rates of decline on the CVLT Delayed Free Recall (per 1 unit increase in RDW %, RDW × time: γ11 = +0.036 ± 0.013; P = 0.007). Among nonanemic participants, RDWs were consistently associated with poorer baseline performance on the Trailmaking Test, Part A (γ01 = +3.11 ± 0.89; P < 0.001) and on the CVLT List A (γ01 = -0.560 ± 0.158; P < 0.001). Moreover, RDWs were associated with poorer baseline performance on the Brief Test of Attention in the total population (γ01 = -0.123 ± 0.039; P = 0.001) and among men (γ01 = -0.221 ± 0.068; P = 0.001). We did not detect an association between hemoglobin (Hb) and baseline cognitive performance or changes over time.

CONCLUSIONS

Elevated RDW had a consistent cross-sectional association with poor cognitive performance in the domains of verbal memory and attention among the nonanemic group in a sample of middle-aged, urban adults. Anemia and Hb concentrations were not associated with cognition. More longitudinal studies are needed to replicate our findings.

Examining Cognitive Decline Across Black and White Participants in the Harvard Aging Brain Study

BACKGROUND

Black Americans are approximately twice as likely to develop dementia as compared to White Americans and the magnitude of this disparity is often attributed to a variety of factors that include psychosocial and vascular risk factors. However, less is known about the potential contribution of Alzheimer's disease pathological differences.

OBJECTIVE

To examine potential differences incross-sectional and longitudinal cognitive performance in black and white participants who were clinically normal at baseline.

METHODS

296 participants (48 African-American/black participants) underwent MRI and amyloid PET at baseline. Linear mixed models were used to examine the main effects of race, years of education, reading ability, Framingham Heart Study cardiovascular risk score (FHS-CVD), white matter hyperintensities (WMH), and amyloid (Aβ) burden on the Preclinical Alzheimer Cognitive Composite-5 (PACC5).

RESULTS

Lower levels of educationalattainment and reading ability were found for blacks compared to whites. By contrast, no differences in FHS-CVD, WMH, or Aβ were found by racial group. Baseline differences in PACC5 score were attenuated after adjusting for educationalfactors, vascular factors, and Aβ, but remained lower for blacks compared to whites (β= -0.24, p = 0.014). Further, blacks demonstrated a faster rate of PACC5 decline longitudinally compared to whites (β  = -0.055, p = 0.025) after adjusting for covariates.

CONCLUSION

Accounting for educationalfactors, vascular factors, and Aβ burden diminished, but did not eliminate, racial differences in PACC5 performance longitudinally. Understanding potential differences in longitudinal cognitive outcomes by race may be important for upcoming secondary prevention trials.

A Framework of Minority Stress: From Physiological Manifestations to Cognitive Outcomes

Cognitive impairment and dementia continue to threaten the aging population. Although no one is immune, certain groups, namely black older persons, are more likely to have a diagnosis of certain dementias. Because researchers have not found a purely biological reason for this disparity, they have turned to a biopsychosocial model. Specifically, black persons in the United States are more likely to live with social conditions that affect their stress levels which in turn affect physiological regulation leading to conditions that result in higher levels of cognitive impairment or dementia. Here we discuss some of these social conditions such as discrimination, education, and socioeconomic status, and how physiological dysregulation, namely allostatic load that can lead to cognitive impairment and dementia in black persons especially.

Cognitive Reserve from the Perspective of Preclinical Alzheimer Disease: 2020 Update

The concept of cognitive reserve (CR) was proposed to account for the discrepancy between levels of brain pathologic process or damage and clinical and cognitive function. We provide a detailed review of prospective longitudinal studies that have investigated the interaction between CR and Alzheimer disease (AD) biomarkers on clinical and cognitive outcomes among individuals with normal cognition at baseline. Current evidence is consistent with the view that higher levels of CR are associated with a delay in the onset of symptoms of mild cognitive impairment and that there may be multiple pathways by which CR exerts its protective effects.

Illiteracy, dementia risk, and cognitive trajectories among older adults with low education

OBJECTIVE

To investigate whether illiteracy was associated with greater risk of prevalent and incident dementia and more rapid cognitive decline among older adults with low education.

METHODS

Analyses included 983 adults (≥65 years old, ≤4 years of schooling) who participated in a longitudinal community aging study. Literacy was self-reported ("Did you ever learn to read or write?"). Neuropsychological measures of memory, language, and visuospatial abilities were administered at baseline and at follow-ups (median [range] 3.49 years [0-23]). At each visit, functional, cognitive, and medical data were reviewed and a dementia diagnosis was made using standard criteria. Logistic regression and Cox proportional hazards models evaluated the association of literacy with prevalent and incident dementia, respectively, while latent growth curve models evaluated the effect of literacy on cognitive trajectories, adjusting for relevant demographic and medical covariates.

RESULTS

Illiterate participants were almost 3 times as likely to have dementia at baseline compared to literate participants. Among those who did not have dementia at baseline, illiterate participants were twice as likely to develop dementia. While illiterate participants showed worse memory, language, and visuospatial functioning at baseline than literate participants, literacy was not associated with rate of cognitive decline.

CONCLUSION

We found that illiteracy was independently associated with higher risk of prevalent and incident dementia, but not with a more rapid rate of cognitive decline. The independent effect of illiteracy on dementia risk may be through a lower range of cognitive function, which is closer to diagnostic thresholds for dementia than the range of literate participants.

Aerobic fitness relates to differential attentional but not language-related cognitive processes

Compelling evidence supports an association between the attribute of aerobic fitness and achievement scores on standardized tests of reading. However, such standardized assessments provide only a broad valuation of a complex network of language related sub-processes that contribute to reading and are heavily confounded by other attention-related processes. The present investigation sought to clarify the nature of the association between aerobic fitness and language processing in a sample of college-aged adults. Participants were bifurcated based on aerobic fitness level and on a separate day were asked to complete a lexical decision task while neuroelectric activity was recorded. Analysis of word-level language-related ERP components revealed no fitness differences. However, lower aerobically-fit individuals elicited smaller amplitude for attention-related ERP components relative to the higher aerobically-fit group. These data provide initial evidence to suggest that fitness-related differences in reading achievement may result from attentional processes rather than acting upon specific language-related processes.

Brain MRI findings related to Alzheimer's disease in older African American adults

Although a substantial body of research has identified brain MRI measures as important markers of Alzheimer's disease (AD) risk, progression, and treatment response, most of that research has been performed in non-Hispanic white American populations, leading to questions about the utility of the brain MRI measures among individuals of other races or ethnicities. African American individuals in particular are under-represented in AD research, and may exhibit differences in prevalence of AD risk factors, prevalence of AD, incidence of AD, the clinical course of cognitive decline, and AD neuropathology, each of which could influence the utility of brain MRI markers. Unfortunately, while current evidence suggests that African Americans exhibit poorer brain health late in life based on brain MRI measurements, several other aspects of brain MRI markers in this population are unclear, including trajectories of brain MRI markers leading up to old age, relationships between traditional brain health risk factors and brain MRI findings, and the status of brain MRI markers as correlates of cognitive impairment. This unclear state of affairs highlights the urgency of future research in which large numbers of older African American adults contribute longitudinal brain MRI measurements concurrent with clinical, cognitive, and molecular biomarker measurements, ideally in the context of AD preventive or therapeutic trials.

Collectivism Is Associated With Greater Neurocognitive Fluency in Older Adults

Neuropsychological research has been limited in the representation of cultural diversity due to various issues, raising questions regarding the applicability of findings to diverse populations. Nonetheless, culture-dependent differences in fundamental psychological processes have been demonstrated. One of the most basic of these, self-construal (individualism, collectivism), is central to how many other differences are interpreted. Self-construals may have possible consequences on social interactions, emotions, motivation, and cognition. This study aimed to evaluate the impact of self-construal on neurocognitive functions in older adults. A total of 86 community-dwelling older adults 60 years and older were assessed with three common self-report measures of self-construal along individualism and collectivism (IC). A cognitive battery was administered to assess verbal and non-verbal fluency abilities. Latent profile analysis (LPA) was used to categorize individuals according to IC, and one-way analyses of covariance (ANCOVA), including relevant covariates (e.g., ethnicity, gender, linguistic abilities), were used to compare neurocognitive functions between individualists and collectivists. Collectivists outperformed individualists on left frontally-mediated measures of verbal fluency (action, phonemic) after controlling for relevant covariates, F_(1,77) = 6.942, p = 0.010, η² = 0.061. Groups did not differ on semantic fluency, non-verbal fluency, or attention/working memory (all ps > 0.05). These findings suggest a cognitive advantage in collectivists for verbal processing speed with an additional contribution of left frontal processes involved in lexicosemantic retrieval. Self-construal may provide a meaningful descriptor for diverse samples in neuropsychological research and may help explain other cross-cultural differences.

Multiple Influences on Cognitive Function Among Urban-Dwelling African Americans

This study examined multiple influences on cognitive function among African Americans, including education, literacy, poverty status, substance use, depressive symptoms, and cardiovascular disease (CVD) risk factors. Baseline data were analyzed from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. Participants were 987 African Americans (mean age 48.5 years, SD = 9.17) who completed cognitive measures assessing verbal learning and memory, nonverbal memory, working memory, verbal fluency, perceptuo-motor speed, attention, and cognitive flexibility. Using preplanned hierarchical regression, cognitive performance was regressed on the following: (1) age, sex, education, poverty status; (2) literacy; (3) cigarette smoking, illicit substance use; (4) depressive symptoms; and (5) number of CVD risk factors. Results indicated that literacy eliminated the influence of education and poverty status in select instances, but added predictive utility in others. In fully adjusted models, results showed that literacy was the most important influence on cognitive performance across all cognitive domains (p < .001); however, education and poverty status were related to attention and cognitive flexibility. Depressive symptoms and substance use were significant predictors of multiple cognitive outcomes, and CVD risk factors were not associated with cognitive performance. Overall, findings underscore the need to develop cognitive supports for individuals with low literacy, educational attainment, and income, and the importance of treating depressive symptoms and thoroughly examining the role of substance use in this population.

Cognitive Reserve Protects Against Memory Decrements Associated With Neuropathology in Traumatic Brain Injury

OBJECTIVE

To evaluate whether cognitive reserve (CR) moderates the relationship between neuropathology and cognitive outcomes after traumatic brain injury (TBI).

SETTING

Outpatient research organization.

PARTICIPANTS

Patients with complicated mild (n = 8), moderate (n = 9), and severe (n = 44) TBI.

DESIGN

Prospective, cross-sectional study.

MAIN MEASURES

Cognitive reserve was estimated using a test of word reading (Wechsler Test of Adult Reading). Diffusion tensor imaging (functional anisotropy) was used to quantify neuropathology. Neuropsychological test scores were submitted to principal components analyses to create cognitive composites for memory, attention, executive function, and processing speed domains.

RESULTS

At lower levels of neuropathology, people with higher CR exhibited better memory than those with lower CR. This benefit diminished as neuropathology increased and disappeared at the highest levels of neuropathology. Cognitive reserve ceased exerting a protective effect at premorbid intelligence levels below average.

CONCLUSION

Cognitive reserve may differentially protect some cognitive domains against neuropathology relative to others. A clinical cutoff below which CR is no longer protective, together with a possible neuropathology ceiling effect, may be instructive for prognostication and clinical decision-making in cognitive rehabilitation.

Pretreatment Psychoneurological Symptoms and Their Association With Longitudinal Cognitive Function and Quality of Life in Older Breast Cancer Survivors

CONTEXT

Symptoms affect quality of life (QOL), functional status, and cognitive function in cancer survivors, but older survivors are understudied.

OBJECTIVES

The objectives of this study were to identify prototypical presystemic therapy psychoneurological symptom clusters among older breast cancer survivors and determine whether these symptom clusters predicted cognition and QOL over time.

METHODS

Women with newly diagnosed nonmetastatic breast cancer (n = 319) and matched noncancer controls (n = 347) aged 60+ years completed questionnaires and neuropsychological tests before systemic therapy and 12 and 24 months later. Latent class analysis identified clusters of survivors based on their pretherapy depression, anxiety, fatigue, sleep disturbance, and pain. Linear mixed-effects models examined changes in objective cognition, perceived cognition, and functional status (Instrumental Activities of Daily Living disability, functional well-being, and breast cancer-specific QOL) by group, controlling for covariates.

RESULTS

Nearly one-fifth of older survivors were classified as having high pretherapy symptoms (n = 51; 16%); the remainder had low symptoms (n = 268; 84%); both groups improved over time on all outcomes. However, compared to the low symptom group and controls, survivors with high symptoms had lower baseline objective cognition and lower perceived cognition at baseline and 24 months, lower functional well-being at baseline and 12 months, greater Instrumental Activities of Daily Living disability at baseline, and lower breast cancer-specific QOL at all time points (all P < 0.05).

CONCLUSION

Nearly one-fifth of older breast cancer survivors had high psychoneurological symptoms at diagnosis, which predicted clinically meaningful decrements in perceived cognition and function in the first 24 months after diagnosis. Pretreatment psychoneurological symptom clusters could identify survivors for monitoring or intervention.

Perspectives on ethnic and racial disparities in Alzheimer's disease and related dementias: Update and areas of immediate need

Alzheimer's disease and related dementias (ADRDs) are a global crisis facing the aging population and society as a whole. With the numbers of people with ADRDs predicted to rise dramatically across the world, the scientific community can no longer neglect the need for research focusing on ADRDs among underrepresented ethnoracial diverse groups. The Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART; alz.org/ISTAART) comprises a number of professional interest areas (PIAs), each focusing on a major scientific area associated with ADRDs. We leverage the expertise of the existing international cadre of ISTAART scientists and experts to synthesize a cross-PIA white paper that provides both a concise "state-of-the-science" report of ethnoracial factors across PIA foci and updated recommendations to address immediate needs to advance ADRD science across ethnoracial populations.

Modern neuropsychological tests for a diversity of cultural contexts

OBJECTIVE

The appropriateness of the current neuropsychological tests for the assessment of different populations has been questioned. In this issue several articles have proposed the modernization of neuropsychological testing by incorporating modern technological devices such as computers, mobile phones, or tablets. This is a commentary on the articles contained in the special issue about the inclusion of modern assessment methods that can be properly used around the world and not only in technologically/economically advanced countries.

METHODS

The author of this article reviewed the articles included in the special issue with the goal of commenting on whether the new approaches proposed would have global relevance and applicability.

RESULTS

The use of biomedical databases and modern technological devices such as computers, wearables and tablets might not be available in many countries, thus leading to a situation in which modern neuropsychological tests might be available only in some world regions. In addition, because in many countries there are large percentages of population with low education these modern neuropsychological tests might not be appropriate for them. Finally, tests developed with culturally specific stimuli will not be applicable in some cultures.

CONCLUSION

This article provides an overview of several issues that should be considered to make neuropsychological tests both modern and accessible around the world, more specifically the cross-cultural appropriateness and accessibility for low educated individuals and availability in low/middle income regions.

Defining Cognitive Reserve and Implications for Cognitive Aging

PURPOSE OF REVIEW

The aim of this review is to summarize current conceptual models of cognitive reserve (CR) and related concepts and to discuss evidence for these concepts within the context of aging and Alzheimer's disease.

RECENT FINDINGS

Evidence to date supports the notion that higher levels of CR, as measured by proxy variables reflective of lifetime experiences, are associated with better cognitive performance, and with a reduced risk of incident mild cognitive impairment/dementia. However, the impact of CR on longitudinal cognitive trajectories is unclear and may be influenced by a number of factors. Although there is promising evidence that some proxy measures of CR may influence structural brain measures, more research is needed. The protective effects of CR may provide an important mechanism for preserving cognitive function and cognitive well-being with age, in part because it can be enhanced throughout the lifespan. However, more research on the mechanisms by which CR is protective is needed.

Relationship between physical and cognitive performance in community dwelling, ethnically diverse older adults: a cross-sectional study

Background

Regular exercise training stimulates physiological adaptations to improve physical performance, reduce chronic disease risk, and slow age-related cognitive decline. Since the physiological mechanisms responsible for aging-associated cognitive decline are not yet fully understood, and training-induced physiological adaptations responsible for performance measure improvements are specific to the type (aerobic vs. strength) and intensity of training, studies are needed to assess the relationships between physical performance measures and cognitive performance in older adults. These results could be used to guide exercise prescriptions with the goal of improving age-related cognitive performance. The purpose of this study was to investigate the relationship between physical performance measures and cognitive performance in a population of community dwelling, ethnically diverse older adults.

Methods

The cognitive performance of ninety independent, community dwelling participants (69 female, 21 male), aged 75 ± 9.5 years (mean ± SD) was measured with the Modified Mini-Mental State Test (3MS), Trailmaking Tests A and B (TMT A & B), and the Animal Naming test. Sociodemographic (age, sex, ethnicity, medication use, years of education) and anthropometric data were collected, physical activity was assessed with the Physical Activity Scale for the Elderly (PASE), peak hand-grip strength, distance walked in the 6MWT, and heart rate pre-, during, and up to 5 min. post- 6MWT were measured. Forward stepwise multiple regression analyses were performed with each cognitive measure as a dependent variable.

Results and Discussion

Controlling for sociodemographic covariates, peak heart rate during the 6MWT (6MWT HR_PEAK) was positively correlated with performance in the 3MS (p < 0.017), and TMT A (p < 0.001) and B (p < 0.029). Controlling for sociodemographic covariates, PASE was positively (p = 0.001), and β-blocker use negatively (p = 0.035), correlated with performance on the Animal Naming test. Also, controlling for sociodemographic covariates, PASE was positively correlated with performance on the TMT A (p = 0.017). Here we show that higher peak heart rate during the 6MWT is positively correlated with cognitive performance in a population of community dwelling, ethnically diverse older adults (ages 60-95 years).

Conclusion

Higher peak heart rate during the 6MWT was found to be independently and positively correlated with cognitive function in community-dwelling older adults. Although additional work is needed, these results are promising and suggest that physicians, exercise professionals, and/or fitness/fall prevention programs may use peak heart rate during the 6MWT to easily monitor exercise intensity to support cognitive health.

The impact of cognitive reserve on neurocognitive performance in Major Depressive Disorder

Cognitive reserve may mitigate the degree of cognitive deficit observed in Major Depressive Disorder (MDD), confounding attempts to fully characterize the nature of these deficits. In this study, cognitive reserve was examined as a potential moderator of neurocognitive deficits in MDD. Unmedicated, currently depressed patients with MDD (n = 269), and healthy volunteers (n = 143) were compared on measures assessing psychomotor speed, interference processing, verbal memory, visual memory, and executive functioning. Moderating effects of education level and estimated intelligence level were examined as interactions, along with age, in a regression model for each test. Differences between patients and non-patients were found with most measures, and sustained in regression models as main effects. However, the interaction of estimated intelligence and patient status was significant for processing speed, verbal memory, visual memory, and executive functioning, with patient/non-patient differences diminishing with higher estimated intelligence. Neither estimated intelligence nor education level impacted interference processing differences, which were reduced with increasing age. Better intellectual ability moderates the effect of MDD on neurocognitive test performance. This effect may confound attempts to characterize these deficits in higher functioning samples. More challenging tasks may be needed, given the potential predictive value of neurocognition for differential therapeutic and clinical outcomes.

Optimal cutoffs for the Montreal Cognitive Assessment vary by race and ethnicity

INTRODUCTION

The Montreal Cognitive Assessment (MoCA), scored from 0 to 30, is used as a screening tool for mild cognitive impairment (MCI). The current cutoff (26) may not be optimal among minorities.

METHODS

Data from the National Alzheimer's Coordinating Center Uniform Data Set March 2018 data freeze was used to calculate optimal cutoffs for detection of MCI and dementia by race/ethnic group and education.

RESULTS

Of the 3895 individuals included, 80.7% were non-Hispanic White, 15.0% were non-Hispanic Black, and 4.2% were Hispanic. Optimal cutoffs for detection of MCI were 25 among non-Hispanic Whites, 24 among Hispanics, and 23 among non-Hispanic Blacks. Optimal cutoffs for detection of dementia were 19 among non-Hispanic Whites and 16 for both non-Hispanic Blacks and Hispanics. Lower educational attainment produced lower optimal cutoffs.

DISCUSSION

Our findings suggest cutoffs may need to be stratified by race/ethnicity and education to ensure detecting MCI from normal and MCI from dementia.

Cognitive Aging in Black and White Americans: Cognition, Cognitive Decline, and Incidence of Alzheimer Disease Dementia

BACKGROUND

US-based studies have reported that older blacks perform worse than older whites on cognitive tests and have higher risk of Alzheimer disease dementia (AD). It is unclear whether these findings reflect differences in cognitive decline.

METHODS

The Chicago Health and Aging Project followed individuals, 65+ years old (64% black, 36% white), for up to 18 years. Participants underwent triennial cognitive assessments; stratified randomized samples underwent assessments for AD. We compared black and white participants' cognitive performance, cognitive decline rate (N = 7,735), and AD incidence (N = 2,144), adjusting for age and sex.

RESULTS

Black participants performed worse than white participants on the cognitive tests; 441 participants developed AD. Black participants' incident AD risk was twice that of whites (RR = 1.9; 95% CI, 1.4, 2.7), with 58 excess cases/1,000 occurring among blacks (95% CI, 28, 88). Among noncarriers of APOE ε4, blacks had 2.3 times the AD risk (95% CI, 1.5, 3.6), but among carriers, race was not associated with risk (RR = 1.1; 95% CI, 0.6, 2.0; Pinteraction = 0.05). However, cognitive decline was not faster among blacks: the black-white difference in 5-year change in global cognitive score was 0.007 standard unit (95% CI, -0.034, 0.047). Years of education accounted for a sizable portion of racial disparities in cognitive level and AD risk, in analyses using a counterfactual approach.

CONCLUSIONS

The higher risk of AD among blacks may stem from lower level of cognitive test performance persisting throughout the observation period rather than faster rate of late-life cognitive decline. Disparities in educational attainment may contribute to these performance disparities. See video abstract at, http://links.lww.com/EDE/B299.

The Relationships Between Cognitive Reserve and Creativity. A Study on American Aging Population

The Cognitive Reserve (CR) hypothesis suggests that the brain actively attempts to cope with neural damages by using pre-existing cognitive processing approaches or by enlisting compensatory approaches. This would allow an individual with high CR to better cope with aging than an individual with lower CR. Many of the proxies used to assess CR indirectly refer to the flexibility of thought. The present paper aims at directly exploring the relationships between CR and creativity, a skill that includes flexible thinking. We tested a sample of 72 adults (aged between 45 and 78) assessing both their level of CR and their creativity. To evaluate CR we used the proxies commonly used in literature, namely, three subtests from the WAIS (vocabulary, similarities, and digit span) and the years of education. We also used an ad-hoc test asking people to report how frequently they tend to perform activities that are believed to increase CR. We used verbal creativity tasks (alternative uses and generation of acronyms) to assess individual levels of creativity. We asked participants to describe their main occupation (present or past) and coded each occupation as creative or not creative. Results (controlling for age-related differences) showed that scores from the WAIS correlated positively with creativity performance, even though correlations varied across the subtests. Focusing on the frequency and type of activities that people perform, and comparing individuals who have or had a creative job to those with a routine job, a clear relationship between creativity and CR emerged. This effect was more relevant than the level of job complexity. Implications for the study of CR and aging are discussed.

Assessing the Readability of Medical Documents: A Ranking Approach

Background

The use of electronic health record (EHR) systems with patient engagement capabilities, including viewing, downloading, and transmitting health information, has recently grown tremendously. However, using these resources to engage patients in managing their own health remains challenging due to the complex and technical nature of the EHR narratives.

Objective

Our objective was to develop a machine learning–based system to assess readability levels of complex documents such as EHR notes.

Methods

We collected difficulty ratings of EHR notes and Wikipedia articles using crowdsourcing from 90 readers. We built a supervised model to assess readability based on relative orders of text difficulty using both surface text features and word embeddings. We evaluated system performance using the Kendall coefficient of concordance against human ratings.

Results

Our system achieved significantly higher concordance (.734) with human annotators than did a baseline using the Flesch-Kincaid Grade Level, a widely adopted readability formula (.531). The improvement was also consistent across different disease topics. This method’s concordance with an individual human user’s ratings was also higher than the concordance between different human annotators (.658).

Conclusions

We explored methods to automatically assess the readability levels of clinical narratives. Our ranking-based system using simple textual features and easy-to-learn word embeddings outperformed a widely used readability formula. Our ranking-based method can predict relative difficulties of medical documents. It is not constrained to a predefined set of readability levels, a common design in many machine learning–based systems. Furthermore, the feature set does not rely on complex processing of the documents. One potential application of our readability ranking is personalization, allowing patients to better accommodate their own background knowledge.

Evaluating Cognitive Reserve Through the Prism of Preclinical Alzheimer Disease

The concept of cognitive reserve (CR) was proposed to account for the discrepancy between levels of brain pathologic features or damage and clinical and cognitive function. This article provides a detailed review of prospective longitudinal studies that have investigated the interaction between CR and Alzheimer's disease (AD) biomarkers on clinical and cognitive outcomes among individuals with preclinical AD. Current evidence shows that higher levels of CR are associated with a delay in the onset of symptoms of mild cognitive impairment and that there may be multiple pathways by which CR exerts its protective effects.

Impacts of Illiteracy on the Risk of Dementia: A Global Health Perspective

Despite its significance as a contributing factor for late-life dementia risk, illiteracy is frequently underappreciated in the management of dementia. In this study, we estimated the proportion of dementia cases attributable to illiteracy using the population attributable fraction (PAF), and calculated to what extent the monetary cost of dementia could be saved in the future by reducing illiteracy from the South Korean, Latin American, South Asian/Middle Eastern, and African populations. We collected necessary data from the 2011 United Nations Human Development Report and prevalence studies conducted in these regions. Additional variables not included in the above sources were estimated using a logit model under a "trend scenario"-based assumption. Around 16% of the total number of dementia cases in South Korea in 2015 can be attributed to illiteracy, with this figure predicted to decline to around 2% by 2050. This translates to a saving in dementia care costs of approximately 52 billion USD, providing we are successful in theoretically eradicating illiteracy as of 2015, in the population aged 65 years or under. Likewise, reducing illiteracy to 50% in Latin America, South Asia/The Middle East, and Africa by 2050 could generate further cost savings of between 71 and 244 billion, 13 and 94 billion, and 17 and 78 billion USD, respectively. Even public policies aimed solely at reducing illiteracy in the childhood, adolescent, or middle-aged population could potentially have a role in the primary prevention of dementia. Moving forward, governments will need to address this issue in a purposeful and systematic manner.

Comparing Alternative Effect Decomposition Methods: The Role of Literacy in Mediating Educational Effects on Mortality

BACKGROUND

Inverse odds ratio weighting, a newly proposed tool to evaluate mediation in exposure-disease associations, may be valuable for a host of research questions, but little is known about its performance in real data. We compare this approach to a more conventional Baron and Kenny type of decomposition on an additive hazards scale to estimate total, direct, and indirect effects using the example of the role of literacy in mediating the effects of education on mortality.

METHODS

Health and Retirement Study participants born in the United States between 1900 and 1947 were interviewed biennially for up to 12 years (N = 17,054). Literacy was measured with a brief vocabulary assessment. Decomposition estimates were derived based on Aalen additive hazards models.

RESULTS

A 1 standard deviation difference in educational attainment (3 years) was associated with 6.7 fewer deaths per 1000 person-years (β = -6.7, 95% confidence interval [CI]: -7.9, -5.4). Of this decrease, 1.3 fewer deaths (β = -1.3, 95% CI: -4.0, 1.2) were attributed to the literacy pathway (natural indirect), representing 19% of the total effect. Baron and Kenny estimates were consistent with inverse odds ratio weighting estimates but were less variable (natural indirect effect: -1.2 [95% CI: -1.7, -0.69], representing 18% of total effect).

CONCLUSION

In a cohort of older Americans, literacy partially mediated the effect of education on mortality. See Video Abstract at http://links.lww.com/EDE/B78.

How Is Literacy Being Defined and Measured in Dementia Research? A Scoping Review

Literacy plays an important role in Alzheimer's disease and related dementias (ADRD); however, less is known about how literacy is being used and defined in ADRD studies. This study reviewed terminology being used to describe types and definitions of literacy and instruments used to assess literacy in ADRD research. Among the 219 studies retrieved from 3 databases, 50 met our inclusion criteria. Literacy terms used in ADRD studies varied: literacy (n = 28), health literacy (n = 9), and dementia literacy (n = 7) were the most often used terms, followed by financial literacy (n = 4), dementia knowledge (n = 3), AD knowledge (n = 2), mental health literacy (n = 2), AD literacy, digital literacy, health literacy about incontinence, and financial knowledge (n = 1 each). Thirty studies did not define literacy terms used. Among the 20 studies defining literacy, definitions were inconsistent across studies even when they used the same term. Surveys (n = 30), open-ended questions, vignettes, or focus groups (n = 10), self-perceived (n = 3) or interviewer assessed (n = 1) literacy levels were used to assess literacy. Ten studies did not specify literacy measurement. Various literacies have been examined in ADRD research with unclear definitions and some inadequate measures. Well-defined terms with valid measures are needed to better understand the role of literacies in ADRD research.

The role of literacy in the association between educational attainment and depressive symptoms

There is a consistent association between education and depressive symptoms, but research on the mechanisms to explain this association remains limited. No study has formally evaluated the extent to which the association between education and depressive symptoms is mediated through a foundational skill such as literacy. Inverse odds ratio weighting (IORW) was used to estimate total, natural direct, and natural indirect effects in examining literacy as a mediator of the association between education and depressive symptoms. Health and Retirement Study participants born in the U.S. between 1900 and 1947 were interviewed biennially for up to 12 years (N = 16,718). Literacy was assessed with a brief vocabulary measure. Depressive symptoms were measured using the 8-item Centers for Epidemiologic Studies-Depression (CES-D) scale. Decomposition estimates were derived using regression analyses of repeated measures of depressive symptoms. Standard errors were obtained using a nonparametric bootstrap with the individual as the independent unit to account for dependence of observations within an individual. In a large cohort of older Americans, a one standard deviation difference in educational attainment (~ 3 years) was associated with a 0.35-point decrement in CES-D score (95% CI: -0.38, -0.32). This decrement represents a 0.22 standard deviation difference in depressive symptoms. Using IORW, the estimated effect of education on depressive symptoms mediated through literacy was -0.10 (95% CI: -0.18, -0.01), which represents 28% of the total effect. Education confers many benefits; as demonstrated by this study for depressive symptoms, one important benefit is literacy.

The Impact of Age and Cognitive Reserve on Resting-State Brain Connectivity

Cognitive reserve (CR) is a protective mechanism that supports sustained cognitive function following damage to the physical brain associated with age, injury, or disease. The goal of the research was to identify relationships between age, CR, and brain connectivity. A sample of 90 cognitively normal adults, ages 45–64 years, had their resting-state brain activity recorded with electroencephalography (EEG) and completed a series of memory and executive function assessments. CR was estimated using years of education and verbal IQ scores. Participants were divided into younger and older age groups and low- and high-CR groups. We observed greater left- than right-hemisphere coherence in younger participants, and greater right- than left-hemisphere coherence in older participants. In addition, greater coherence was observed under eyes-closed than eyes-open recording conditions for both low-CR and high-CR participants, with a more substantial difference between recording conditions in individuals high in CR regardless of age. Finally, younger participants low in CR exhibited greater mean coherence than younger participants high in CR, whereas the opposite pattern was observed in older participants, with greater coherence in older participants high in CR. Together, these findings suggest the possibility of a shift in the relationship between CR and brain connectivity during aging.

Subjective cognitive concerns are associated with objective memory performance in Caucasian but not African-American persons

Objective

subjective cognitive concerns (SCC) have been proposed as a means of identifying individuals at risk for Alzheimer's disease (AD). However, the utility of SCCs has not been well-explored for African-Americans, who are twice as likely to develop AD dementia as Caucasians. We investigated whether race affects the association between SCCs and objective memory performance.

Methods

we used a composite of three SCC questionnaires, and three challenging episodic memory tests. We studied 289 (61% female; African-American n = 47) clinically normal older individuals. Two hierarchical linear regressions assessed the modifying role of race on the association between SCC and objective memory performance. The first regression was conducted on the full sample, while the second matched the racial groups on age, estimated verbal IQ and socioeconomic status.

Results

in the full sample, both groups reported similar levels of SCCs, P = 0.10, although African-Americans performed worse on the memory tasks, P < 0.001. No group differences were observed in the matched sample. The SCC × race interaction term was nonsignificant in the full sample, β = 0.109, P = 0.09, but was significant in the matched sample, β = 0.422, P = 0.037. While a significant correlation was observed between SCCs and memory among Caucasians, r = -0.401, the correlation was not found among African-Americans, r = -0.052.

Conclusions

results suggest that the dissociation between SCCs and memory performance in African-Americans may indicate qualitative differences in how diverse groups endorse cognitive concerns, even after considering socioeconomic and educational factors.

Cognitive reserve and long-term change in cognition in aging and preclinical Alzheimer's disease

We examined if baseline levels of cognitive reserve (CR) and of Alzheimer's disease (AD) biomarkers modify the rate of change in cognition among individuals with normal cognition at baseline (n = 303, mean baseline age = 57 years, mean follow-up = 12 years); 66 participants subsequently developed mild cognitive impairment (MCI) or dementia due to AD. CR was indexed by years of education, reading, and vocabulary measures. AD biomarkers were measured with a composite score composed of measures of amyloid, phosphorylated tau, and neurodegeneration. Higher CR scores were associated with better cognitive performance but did not modify the rate of change in cognition among those who remained cognitively normal, nor among those who progressed to MCI before symptom onset, independent of baseline biomarker levels. However, higher CR scores were associated with faster cognitive decline after symptom onset of MCI. These results suggest that the mechanism by which CR mediates the relationship between pathology and cognitive function is by delaying the onset of symptoms rather than reducing the rate of cognitive decline.

Cerebrospinal Fluid Biomarkers and Reserve Variables as Predictors of Future "Non-Cognitive" Outcomes of Alzheimer's Disease

BACKGROUND

The influence of reserve variables and Alzheimer's disease (AD) biomarkers on cognitive test performance has been fairly well-characterized. However, less is known about the influence of these factors on "non-cognitive" outcomes, including functional abilities and mood.

OBJECTIVE

We examined whether cognitive and brain reserve variables mediate how AD biomarker levels in cognitively normal persons predict future changes in function, mood, and neuropsychiatric behavior.

METHODS

Non-cognitive outcomes were examined in 328 individuals 50 years and older enrolled in ongoing studies of aging and dementia at the Knight Alzheimer Disease Research Center (ADRC). All participants were cognitively normal at baseline (Clinical Dementia Rating [CDR] 0), completed cerebrospinal fluid (CSF) and structural neuroimaging studies within one year of baseline, and were followed for an average of 4.6 annual visits. Linear mixed effects models explored how cognitive reserve and brain reserve variables mediate the relationships between AD biomarker levels and changes in function, mood, and neuropsychiatric behavior in cognitively normal participants.

RESULTS

Education levels did not have a significant effect on predicting non-cognitive decline. However, participants with smaller brain volumes exhibited the worst outcomes on measures of mood, functional abilities, and behavioral disturbance. This effect was most pronounced in individuals who also had abnormal CSF biomarkers.

CONCLUSIONS

The findings suggest that brain reserve plays a stronger, or earlier, role than cognitive reserve in protecting against non-cognitive impairment in AD.

Health Variables Are Informative in Screening for Mild Cognitive Impairment Among Elderly African Americans

To aid primary care providers in identifying people at increased risk for cognitive decline, we explored the relative importance of health and demographic variables in detecting potential cognitive impairment using the Mini-Mental State Examination (MMSE). Participants were 94 older African Americans coming to see their primary care physicians for reasons other than cognitive complaints. Education was strongly associated with cognitive functioning. Among those with at least 9 years of education, patients with more vascular risk factors were at greater risk for mild cognitive impairment. For patients with fewer than 9 years of education, those with fewer prescribed medications were at increased risk for dementia. These results suggest that in addition to the MMSE, primary care physicians can make use of patients' health information to improve identification of patients at increased risk for cognitive impairment. With improved identification, physicians can implement strategies to mitigate the progression and impact of cognitive difficulties.

The reciprocal relationship between participation in leisure activities and cognitive functioning: the moderating effect of self-rated literacy level

OBJECTIVE

Participation in leisure activities is beneficial for cognitive functioning of older adults, but it is less known whether it is also beneficial for those with low basic cognitive level. This study examined the reciprocal relationship between participating in leisure activities and cognitive functioning among low and higher literacy level older adults.

METHOD

Respondents aged 60 years and older who participated in both first waves (2005-2006 and 2009-2010) of the Israeli component of the Survey of Health, Ageing and Retirement in Europe (SHARE-Israel) were divided into low (n = 139) and higher literacy level respondents (n = 714). They reported participation in leisure activities and completed measures of cognitive functioning at both waves.

RESULTS

Cross-lagged models showed that participation in leisure activities predicted higher cognitive functioning four years later only among older adults with low literacy level. On the other hand, cognitive functioning predicted more participation in leisure activities four years later only among higher literacy level older adults.

CONCLUSIONS

Participating in leisure activities may be especially beneficial to cognitive functioning among older adults with low literacy level, as their initial low cognitive level allows more room for cognitive improvement than among higher literacy level older adults. Public efforts aimed at increasing participation in leisure activities may therefore target particularly older adults with low basic cognitive level.

Grit in adolescence is protective of late-life cognition: non-cognitive factors and cognitive reserve

Various psychological assets have been shown to protect against late-life cognitive impairment by promoting cognitive reserve. While factors such as educational attainment and IQ are well-established contributors to cognitive reserve, noncognitive factors, such as grit, have not been studied in this regard. We examined the contribution of adolescent grit, indexed by high school class rank controlling for IQ, to late-life cognition and its decline among approximately 4000 participants in the Wisconsin Longitudinal Study, a random sample of high school graduates followed from 1957 to 2011. Adolescent grit significantly predicted both immediate and delayed memory at ages 64 and 71, over and above the contribution of IQ. While the relative contributions of IQ and grit to immediate memory were comparable, grit was a stronger predictor of delayed memory. Cognitive reserve has noncognitive, as well as cognitive, components.

Cognitive reserve and self-efficacy as moderators of the relationship between stress exposure and executive functioning among spousal dementia caregivers

BACKGROUND

A substantial literature has reported that stress negatively impacts on cognitive processes. As dementia caregiving can be stressful, it has been hypothesized that the challenges of dementia care may increase caregivers' own vulnerability to cognitive decline. Prefrontal processes are thought to be most vulnerable to stress; however, few studies have examined whether greater caregiver stress predicts poorer executive dysfunction, and no previous research has considered potential moderators of this relationship. We examined (1) whether greater psychological stress mediated a relationship between caregiver stress exposure and executive functioning and (2) whether greater self-efficacy and cognitive reserve (CR) moderated this relationship.

METHOD

Spousal dementia caregivers (n = 253) completed the Neuropsychiatric Inventory Questionnaire (stress exposure), the Perceived Stress Scale, the National Adult Reading Test (CR), the Fortinsky dementia-specific caregiver self-efficacy scale, and the Color Trails Test (executive functioning). Moderated mediation was tested using the PROCESS macro. Age, gender, and dementia risk factors were included as covariates.

RESULTS

Greater stress exposure indirectly predicted executive functioning through psychological stress. Stronger relationships between greater psychological stress and poorer executive functioning were observed among caregivers with lower CR; there was no evidence that self-efficacy moderated the relationship between stress exposure and psychological stress.

CONCLUSIONS

Our findings are in line with the idea that greater psychological stress in response to challenges associated with dementia care predicts poorer caregiver executive functioning, particularly among caregivers with low CR. However, these findings are cross sectional; it is also possible that poorer executive functioning contributes to greater caregiver stress.

Cognitive reserve and cortical thickness in preclinical Alzheimer's disease

This study examined whether cognitive reserve (CR) alters the relationship between magnetic resonance imaging (MRI) measures of cortical thickness and risk of progression from normal cognition to the onset of clinical symptoms associated with mild cognitive impairment (MCI). The analyses included 232 participants from the BIOCARD study. Participants were cognitively normal and largely middle aged (M age = 56.5) at their baseline MRI scan. After an average of 11.8 years of longitudinal follow-up, 48 have developed clinical symptoms of MCI or dementia (M time from baseline to clinical symptom onset = 7.0 years). Mean thickness was measured over eight 'AD vulnerable' cortical regions, and cognitive reserve was indexed by a composite score consisting of years of education, reading, and vocabulary measures. Using Cox regression models, CR and cortical thickness were each independently associated with risk of clinical symptom onset within 7 years of baseline, suggesting that the neuronal injury occurring proximal to symptom onset has a direct association with clinical outcomes, regardless of CR. In contrast, there was a significant interaction between CR and mean cortical thickness for risk of progression more than 7 years from baseline, suggesting that individuals with high CR are better able to compensate for cortical thinning that is beginning to occur at the very earliest phase of AD.

Health and Functional Literacy in Physical Rehabilitation Patients

BACKGROUND

People with disabilities, who face multiple barriers to care, experience health disparities, yet few studies have measured health literacy in this population.

OBJECTIVE

This study evaluated functional literacy, health literacy, fluid cognitive function, and self-reported health in people who live in community dwellings with spinal cord injury, stroke, or traumatic brain injury.

METHODS

Participants with a traumatic spinal cord injury, stroke, or traumatic brain injury, one-year postinjury, and age 18 to 85 years, completed a battery of instruments at three medical centers in the Midwestern U.S.: functional literacy (word recognition, vocabulary knowledge), health literacy (comprehension of prose, document, and quantitative health information), fluid cognitive function (memory, executive function, and processing speed), and patient-reported outcomes (mobility, fatigue, sadness, anxiety, social function, and overall health).

KEY RESULTS

There were strong correlations between functional literacy, health literacy, and fluid cognitive function. After adjustment for sociodemographic and clinical characteristics, higher health literacy was associated with better mobility, less anxiety, and better overall health; higher functional literacy was associated with less anxiety and better overall health; and higher fluid cognitive function was associated with better mobility, less sadness, better social function, and better overall health.

CONCLUSIONS

To effectively address limited health literacy among people with spinal cord injury, stroke, and traumatic brain injury, and ensure that they are able to be informed partners in their health care, intervention is required at the level of patients, providers, and health care delivery systems. A special consideration is to ensure that health information is both well-targeted to people's health literacy levels and accessible for people with a range of physical, cognitive, and sensory limitations. The multimedia self-administered health literacy measure used in this study could be useful to rehabilitation providers and designers of health information and interfaces. [Health Literacy Research and Practice. 2017;1(2):e71-e85.].

PLAIN LANGUAGE SUMMARY

Health literacy represents people's abilities to obtain, understand, and use health information to make informed decisions about their health and health care. People with disabilities face physical, attitudinal, economic, and structural barriers to care. Consideration of health literacy in rehabilitation practice can enhance the effectiveness of the patient-clinician relationship and help address the needs of this population.

Pathways linking health literacy, health beliefs, and cognition to medication adherence in older adults with asthma

BACKGROUND

Limited health literacy is associated with low adherence to asthma controller medications among older adults.

OBJECTIVE

We sought to describe the causal pathway linking health literacy to medication adherence by modeling asthma illness and medication beliefs as mediators.

METHODS

We recruited adults aged 60 years and older with asthma from hospital and community practices in New York, New York, and Chicago, Illinois. We measured health literacy and medication adherence using the Short Test of Functional Health Literacy in Adults and the Medication Adherence Rating Scale, respectively. We used validated instruments to assess asthma illness and medication beliefs. We assessed cognition using a cognitive battery. Using structural equation modeling, we modeled illness and medication beliefs as mediators of the relationship between health literacy and adherence while controlling for cognition.

RESULTS

Our study included 433 patients with a mean age of 67 ± 6.8 years. The sample had 84% women, 31% non-Hispanic blacks, and 39% Hispanics. The 36% of patients with limited health literacy were more likely to have misconceptions about asthma (P < .001) and asthma medications (P < .001). Health literacy had a direct effect (β = 0.089; P < .001) as well as an indirect effect on adherence mediated by medications concerns (β = 0.033; P = .002). Neither medication necessity (β = 0.044; P = .138) nor illness beliefs (β = 0.007; P = .143) demonstrated a mediational role between health literacy and adherence.

CONCLUSIONS

Interventions designed to improve asthma controller medication adherence in older adults may be enhanced by addressing concerns about medications in addition to using communication strategies appropriate for populations with limited health literacy and cognitive impairments.

Validation of a Dynamic Measure of Current Cognitive Reserve in a Longitudinally Assessed Sample of Healthy Older Adults: The Tasmanian Healthy Brain Project

Cognitive reserve (CR) is a theoretical construct describing the underlying cognitive capacity of an individual that confers differential levels of resistance to, and recovery from, brain injuries of various types. To date, estimates of an individual's level of CR have been based on single proxy measures that are retrospective and static in nature. To develop a measure of dynamic change in CR across a lifetime, we previously identified a latent factor, derived from an exploratory factor analysis of a large sample of healthy older adults, as current CR (cCR). In the present study, we examined the longitudinal results of a sample of 272 older adults enrolled in the Tasmanian Healthy Brain Project. Using results from 12-month and 24-month reassessments, we examined the longitudinal validity of the cCR factor using confirmatory factor analyses. The results of these analyses indicate that the cCR factor structure is longitudinally stable. These results, in conjunction with recent results from our group demonstrating dynamic increases in cCR over time in older adults undertaking further education, lend weight to this cCR measure being a valid estimate of dynamic change in CR over time.

Computerized Cognitive Testing for Use in Clinical Trials: A Comparison of the NIH Toolbox and Cogstate C3 Batteries

BACKGROUND

As prevention trials for Alzheimer's disease move into asymptomatic populations, identifying older individuals who manifest the earliest cognitive signs of Alzheimer's disease is critical. Computerized cognitive testing has the potential to replace current gold standard paper and pencil measures and may be a more efficient means of assessing cognition. However, more empirical evidence about the comparability of novel computerized batteries to paper and pencil measures is required.

OBJECTIVES

To determine whether two computerized IPad batteries, the NIH Toolbox Cognition Battery and Cogstate-C3, similarly predict subtle cognitive impairment identified using the Preclinical Alzheimer Cognitive Composite (PACC).

DESIGN, SETTING, PARTICIPANTS

A pilot sample of 50 clinically normal older adults (Mage=68.5 years±7.6, 45% non-Caucasian) completed the PACC assessment, and the NIH Toolbox and Cogstate-C3 at research centers of Massachusetts General and Brigham and Women's Hospitals. Participants made 3-4 in-clinic visits, receiving the PACC first, then the NIH Toolbox, and finally the Cogstate-C3.>= 0.5SD), versus subtle cognitive impairment (<0.5SD). Composites for each computerized battery were created using principle components analysis, and compared with the PACC using non-parametric Spearman correlations. Logistic regression analyses were used to determine which composite was best able to classify subtle cognitive impairment from typical performance.

RESULTS

The NIH Toolbox formed one composite and exhibited the strongest within-battery alignment, while the Cogstate-C3 formed two distinct composites (Learning-Memory and Processing Speed-Attention). The NIH Toolbox and C3 Learning-Memory composites exhibited positive correlations with the PACC (ρ=0.49, p<0.001; ρ=0.58, p<0.001, respectively), but not the C3 Processing Speed-Attention composite, ρ=-0.18, p=0.22. The C3 Learning-Memory was the only composite that classified subtle cognitive impairment, and demonstrated the greatest sensitivity (62%) and specificity (81%) for that subtle cognitive impairment.

CONCLUSIONS

Preliminary findings suggest that the NIH Toolbox has the advantage of showing the strongest overall clustering and alignment with standardized paper-and-pencil tasks. By contrast, Learning-Memory tasks within the Cogstate-C3 battery have the greatest potential to identify cross-sectional, subtle cognitive impairment as defined by the PACC.

How should proxies of cognitive reserve be evaluated in a population of healthy older adults?

BACKGROUND

While some tools have been developed to estimate an individual's cognitive reserve (CR), no study has assessed the adequacy of the method used for assessing these CR proxy indicators. Therefore, we aimed to determine the most appropriate method to estimate CR by comparing two approaches: (1) the common assessment of CR proxies in the literature (e.g. years of education) and (2) the calculation of a comprehensive index based on most significant parameters used in the estimation of CR.

METHODS

Data on CR proxies (i.e. education, occupation, and leisure activities) were obtained in a sample of 204 older adults. Regression analyses were used to develop the two indices of CR (i.e. ICR-standard and ICR-detailed) and to determine which index best represented the level of one's CR.

RESULTS

The ICR-standard was calculated using a combination of the three most common measures of reserve in the literature: number of schooling years, complexity of the primary occupation, and amount of current participation in stimulating activities. The ICR-detailed was calculated using the most significant parameters (established in initial analyses) of CR: highest level of education combined with the number of training courses, last occupation, and amount of current participation in social and intellectual activities. The comparison of both indices showed that higher levels of ICR-standard and ICR-detailed were associated with a greater minimization of the effects of age on cognition. However, the ICR-detailed was more strongly associated to this minimization than the ICR-standard, suggesting that the ICR-detailed best reflect one's CR.

CONCLUSIONS

This study is the first to show that it is of great importance to question methods measuring CR proxies in order to develop a clinical tool allowing a comprehensive and accurate estimation of CR.

Dual-task costs in aging are predicted by formal education

The capacity to manage different concurrent tasks at the same time decays in older adults. There is however a considerable amount of inter-individual variability in this capacity even in healthy aging. The purpose of this empirical study is to investigate which factors help explaining this variability. A dual-task paradigm was administered to 64 older adults and 31 younger controls. In this paradigm, a primary simple response time task had to be carried out either by itself (single-task condition) or while concurrently performing a secondary subtraction task (dual-task condition). Dual-task costs were operationalized by comparing dual-task and single-task conditions. Older adults showed higher dual-task interference than younger controls. Within the older group, the influence of age, general cognitive abilities, performance on the secondary task, and years of formal education was assessed with a multiple regression analysis. The results showed that years of formal education in older adults were the best predictor that significantly explained a portion of the variance in dual-task performance. These findings extend previous literature by showing that formal education provides an important dose of cognitive reserve, which is useful to successfully implement cognitive dual-task management despite aging.