Cognitive decline and literacy among ethnically diverse elders

Formal education level versus self-rated literacy as predictors of cognitive aging

OBJECTIVES

To compare the prediction of cognitive functioning by formal education and self-rated literacy and the differences in prediction across younger and older cohorts.

METHOD

Data on 28,535 respondents were drawn from a cross-sectional representative sample of community-dwelling older individuals (≥50), participating in the Survey of Health, Ageing, and Retirement in Europe. Education level was classified according to the International Standard Classification of Education 1997 (ISCED-1997) self-rated literacy was determined by having respondents rate their reading and writing on 1-5 scales. Cognitive functioning was measured by verbal recall, word fluency, and arithmetic ability.

RESULTS

Structural equation modeling demonstrated that self-rated literacy was more strongly associated with cognitive functioning than was education level, with or without additional exogenous variables (age, sex, household income, medical conditions, activities of daily living, reading eyesight, and country). The association between education level and cognitive functioning was weaker in older than in younger age groups, whereas the association between self-rated literacy and cognitive functioning showed the opposite trend.

DISCUSSION

Self-rated literacy was found to be a better predictor of late-life cognitive functioning than was the level of formal education. The results have implications for studies of age-related differences in which education level is taken into account.

Low health literacy, limited English proficiency, and health status in Asians, Latinos, and other racial/ethnic groups in California

This study estimated health status by low health literacy and limited English proficiency alone and in combination for Latino, Chinese, Korean, Vietnamese, and White respondents in a population-based sample: 48,427 adults from the 2007 California Health Interview Survey, including 3,715 with limited English proficiency. Multivariate logistic models examined self-reported health by health literacy and English proficiency in the full sample and in racial/ethnic subgroups. Overall, 44.9% with limited English proficiency reported low health literacy, versus 13.8% of English speakers. Among the limited English proficient, Chinese respondents had the highest prevalence of low health literacy (68.3%), followed by Latinos (45.3%), Koreans (35.6%), Vietnamese (29.7%), and Whites (18.8%). In the full sample, respondents with both limited English proficiency/low health literacy reported the highest prevalence of poor health (45.1%), followed by limited English proficiency-only (41.1%), low health literacy-only (22.2%), and neither (13.8%), a hierarchy that remained significant in multivariate models. However, subanalyses revealed that limited English proficient Latinos, Vietnamese, and Whites had equal or greater odds of poor health compared with low health literate/limited English proficient respondents. Individuals with both limited English proficiency and low health literacy are at high risk for poor health. Limited English proficiency may carry greater health risk than low health literacy, though important racial/ethnic variations exist.

The effects of print exposure on sentence processing and memory in older adults: Evidence for efficiency and reserve

The present study was an examination of how exposure to print affects sentence processing and memory in older readers. A sample of older adults (N = 139; Mean age = 72) completed a battery of cognitive and linguistic tests and read a series of sentences for recall. Word-by-word reading times were recorded and generalized linear mixed effects models were used to estimate components representing attentional allocation to word-level and textbase-level processes. Older adults with higher levels of print exposure showed greater efficiency in word-level processing and in the immediate instantiation of new concepts, but allocated more time to semantic integration at clause boundaries. While lower levels of working memory were associated with smaller wrap-up effects, individuals with higher levels of print exposure showed a reduced effect of working memory on sentence wrap-up. Importantly, print exposure was not only positively associated with sentence memory, but was also found to buffer the effects of working memory on sentence recall. These findings suggest that the increased efficiency of component reading processes that come with life-long habits of literacy buffer the effects of working memory decline on comprehension and contribute to maintaining skilled reading among older adults.

Exploring the neural basis of cognitive reserve in aging

The concept of reserve arose from the mismatch between the extent of brain changes or pathology and the clinical manifestations of these brain changes. The cognitive reserve hypothesis posits that individual differences in the flexibility and adaptability of brain networks underlying cognitive function may allow some people to cope better with brain changes than others. Although there is ample epidemiologic evidence for cognitive reserve, the neural substrate of reserve is still a topic of ongoing research. Here we review some representative studies from our group that exemplify possibilities for the neural substrate of reserve including neural reserve, neural compensation, and generalized cognitive reserve networks. We also present a schematic overview of our ongoing research in this area. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

Influence of reading ability on neuropsychological performance in African American elders

Use of normative data stratified by education may result in misclassification of African American older adults because reading ability, an estimate of educational attainment, is lower than reported years of education for some African American elders. This study examined the contribution of reading ability versus education to neuropsychological test performance in 86 community-dwelling African American elders ages 56-91 with 8-18 years of education. Hierarchical multiple regression analyses revealed that reading ability, but not education, was significantly associated with performances on the Trail Making Test, Controlled Oral Word Association Test, Animal Naming, Digit Span, and the Stroop test. Reading ability was not significantly related to performances on measures of memory. Medium to large effect sizes (Cohen's d = 0.58-1.41) were found when comparing mean performances on neuropsychological measures in groups with low versus high reading scores. Results indicate that reading ability contributes beyond educational attainment to performances on some neuropsychological measures among African American elders. These findings have implications for reducing misclassification among minority populations through the use of appropriate normative data.

Mini-Mental State Exam performance of older African Americans: effect of age, gender, education, hypertension, diabetes, and the inclusion of serial 7s subtraction versus "world" backward on score

The Mini-Mental State Exam (MMSE) is a clinically ubiquitous yet incompletely standardized instrument. Though the test offers considerable examiner leeway, little data exist on the normative consequences of common administration variations. We sought to: (a) determine the effects of education, age, gender, health status, and a common administration variation (serial 7s subtraction vs. "world" spelled backward) on MMSE score within a minority sample, (b) provide normative data stratified on the most empirically relevant bases, and (c) briefly address item failure rates. African American citizens (N = 298) aged 55-87 living independently in the community were recruited by advertisement, community recruitment, and word of mouth. Total score with "world" spelled backward exceeded total score with serial 7s subtraction across all levels of education, replicating findings in Caucasian samples. Education is the primary source of variance on MMSE score, followed by age. In this cohort, women out-performed men when "world" spelled backward was included, but there was no gender effect when serial 7s subtraction was included in MMSE total score. To ensure an appropriate interpretation of MMSE scores, reports, whether clinical or in publications of research findings, should be explicit regarding the administration method. Stratified normative data are provided.

Demographically corrected norms for African Americans and Caucasians on the Hopkins Verbal Learning Test-Revised, Brief Visuospatial Memory Test-Revised, Stroop Color and Word Test, and Wisconsin Card Sorting Test 64-Card Version

Memory and executive functioning are two important components of clinical neuropsychological (NP) practice and research. Multiple demographic factors are known to affect performance differentially on most NP tests, but adequate normative corrections, inclusive of race/ethnicity, are not available for many widely used instruments. This study compared demographic contributions for widely used tests of verbal and visual learning and memory (Brief Visual Memory Test-Revised, Hopkins Verbal Memory Test-Revised) and executive functioning (Stroop Color and Word Test, Wisconsin Card Sorting Test-64) in groups of healthy Caucasians (n = 143) and African Americans (n = 103). Demographic factors of age, education, gender, and race/ethnicity were found to be significant factors on some indices of all four tests. The magnitude of demographic contributions (especially age) was greater for African Americans than for Caucasians on most measures. New, demographically corrected T-score formulas were calculated for each race/ethnicity. The rates of NP impairment using previously published normative standards significantly overestimated NP impairment in African Americans. Utilizing the new demographic corrections developed and presented herein, NP impairment rates were comparable between the two race/ethnicities and were unrelated to the other demographic characteristics (age, education, gender) in either race/ethnicity group. Findings support the need to consider extended demographic contributions to neuropsychological test performance in clinical and research settings.

A life course model of cognitive activities, socioeconomic status, education, reading ability, and cognition

OBJECTIVES

To cross-sectionally quantify the contribution of proxy measures of cognitive reserve reflective of the lifespan, such as education, socioeconomic status (SES), reading ability, and cognitive activities, in explaining late-life cognition.

DESIGN

Prospective observational cohort study of aging.

SETTING

Retirement communities across the Chicago metropolitan area.

PARTICIPANTS

Nine hundred fifty-one older adults free of clinical dementia in the Rush Memory and Aging Project (aged 79 ± 8, 74% female).

MEASUREMENTS

Baseline data on multiple life course factors included early-, mid-, and late-life participation in cognitive activities; early-life and adult SES; education; and reading ability (National Adult Reading Test; NART). Path analysis quantified direct and indirect standardized effects of life course factors on global cognition and five cognitive domains (episodic memory, semantic memory, working memory, visuospatial ability, perceptual speed).

RESULTS

Adjusting for age, sex, and race, education had the strongest association with global cognition, episodic memory, semantic memory, and visuospatial ability, whereas NART (followed by education) had the strongest association with working memory. Late-life cognitive activities had the strongest association with perceptual speed, followed by education.

CONCLUSIONS

These cross-sectional findings suggest that education and reading ability are the most-robust proxy measures of cognitive reserve in relation to late-life cognition. Additional research leveraging path analysis is warranted to better understand how these life course factors, reflecting the latent construct of cognitive reserve, affect abnormal cognitive aging.

Explaining differences in episodic memory performance among older African Americans and Whites: the roles of factors related to cognitive reserve and test bias

Older African Americans tend to perform poorly in comparison with older Whites on episodic memory tests. Observed group differences may reflect some combination of biological differences, measurement bias, and other confounding factors that differ across groups. Cognitive reserve refers to the hypothesis that factors, such as years of education, cognitive activity, and socioeconomic status, promote brain resilience in the face of pathological threats to brain integrity in late life. Educational quality, measured by reading test performance, has been postulated as an important aspect of cognitive reserve. Previous studies have not concurrently evaluated test bias and other explanations for observed differences between older African Americans and Whites. We combined data from two studies to address this question. We analyzed data from 273 African American and 720 White older adults. We assessed DIF using an item response theory/ordinal logistic regression approach. DIF and factors associated with cognitive reserve did not explain the relationship between race, and age- and sex-adjusted episodic memory test performance. However, reading level did explain this relationship. The results reinforce the importance of considering education quality, as measured by reading level, when assessing cognition among diverse older adults.

Diversity and disparity in dementia: the impact of ethnoracial differences in Alzheimer disease

Debate exists regarding differences in the prevalence of Alzheimer disease (AD) in African Americans and Hispanics in the United States, with some evidence suggesting that the prevalence of AD may be considerably higher in these groups than in non-Hispanic whites. Despite this possible disparity, patients of minority ethnoracial groups often receive delayed diagnosis or inadequate treatment for dementia. This review investigates these disparities by conceptualizing the dementia disease process as a product of both biological and cultural factors. Ethnoracial differences in biological risk factors, such as genetics and cardiovascular disease, may help to explain disparities in the incidence and prevalence of AD, whereas race-specific cultural factors may impact diagnosis and treatment. Cultural factors include differences in perceptions about what is normal aging and what is not, lack of adequate access to medical care, and issues of trust between minority groups and the medical establishment. The diagnosis of AD in diverse populations may also be complicated by racial biases inherent in cognitive screening tools widely used by clinicians, but controlling for literacy level or using savings scores in psychometric analyses has the potential to mitigate these biases. We also suggest that emerging biomarker-based diagnostic tools may be useful in further characterizing diverse populations with AD. Recognizing the gap in communication that exists between minority communities and the medical research community, we propose that education and outreach are a critical next step in the effort to understand AD as it relates to diverse populations.

Prevention of dementia

Dementia is a neurological condition that is characterized by decline in multiple cognitive domains and is accompanied by a functional impairment. It is important to identify the factors that may delay the onset, slow the progression, or prevent cognitive decline. This review highlights the protective and risk factors of dementia, suggesting that physical activity, intellectual activity, and social engagement may reduce Alzheimer disease and cognitive decline and may be also helpful for enhancing quality of life.

Low health literacy associates with increased mortality in ESRD

Limited health literacy is common in the United States and associates with poor clinical outcomes. Little is known about the effect of health literacy in patients with advanced kidney disease. In this prospective cohort study we describe the prevalence of limited health literacy and examine its association with the risk for mortality in hemodialysis patients. We enrolled 480 incident chronic hemodialysis patients from 77 dialysis clinics between 2005 and 2007 and followed them until April 2008. Measured using the Rapid Estimate of Adult Literacy in Medicine, 32% of patients had limited (<9th grade reading level) and 68% had adequate health literacy (≥9th grade reading level). Limited health literacy was more likely in patients who were male and non-white and who had fewer years of education. Compared with adequate literacy, limited health literacy associated with a higher risk for death (HR 1.54; 95% CI 1.01 to 2.36) even after adjustment for age, sex, race, and diabetes. In summary, limited health literacy is common and associates with higher mortality in chronic hemodialysis patients. Addressing health literacy may improve survival for these patients.

Measuring cognitive reserve based on the decomposition of episodic memory variance

In later adulthood brain pathology becomes common and trajectories of cognitive change are heterogeneous. Among the multiple determinants of late-life cognitive course, cognitive reserve has been proposed as an important factor that modifies or buffers the impact of brain pathology on cognitive function. This article presents and investigates a novel method for measuring and investigating such factors. The core concept is that in a population where pathology is common and variably present, 'reserve' may be defined as the difference between the cognitive performance predicted by an individual's level of pathology and that individual's actual performance. By this definition, people whose measured cognitive performance is better than predicted by pathology have high reserve, whereas those who perform worse than predicted have low reserve. To test this hypothesis, we applied a latent variable model to data from a diverse ageing cohort and decomposed the variance in a measure of episodic memory into three components, one predicted by demographics, one predicted by pathology as measured by structural MRI and a 'residual' or 'reserve' term that included all remaining variance. To investigate the plausibility of this approach, we then tested the residual component as an operational measure of reserve. Specific predictions about the effects of this putative reserve measure were generated from a general conceptual model of reserve. Each was borne from the results. The results show that the current level of reserve, as measured by this decomposition approach, modifies rates of conversion from mild cognitive impairment to dementia, modifies rates of longitudinal decline in executive function and, most importantly, attenuates the effect of brain atrophy on cognitive decline such that atrophy is more strongly associated with cognitive decline in subjects with low reserve than in those with high reserve. Decomposing the variance in cognitive function scores offers a promising new approach to the measure and study of cognitive reserve.

The impact of brain size on pilot performance varies with aviation training and years of education

Previous studies have consistently reported age-related changes in cognitive abilities and brain structure. Previous studies also suggest compensatory roles for specialized training, skill, and years of education in the age-related decline of cognitive function. The Stanford/VA Aviation Study examines the influence of specialized training and skill level (expertise) on age-related changes in cognition and brain structure. This preliminary report examines the effect of aviation expertise, years of education, age, and brain size on flight simulator performance in pilots aged 45-68 years. Fifty-one pilots were studied with structural magnetic resonance imaging, flight simulator, and processing speed tasks. There were significant main effects of age (p < .01) and expertise (p < .01), but not of whole brain size (p > .1) or education (p > .1), on flight simulator performance. However, even though age and brain size were correlated (r = -0.41), age differences in flight simulator performance were not explained by brain size. Both aviation expertise and education were involved in an interaction with brain size in predicting flight simulator performance (p < .05). These results point to the importance of examining measures of expertise and their interactions to assess age-related cognitive changes.

Literacy, cognitive ability, and the retention of health-related information about colorectal cancer screening

Interventions to mitigate the impact of low literacy on patients' recall of information by simplifying language have had limited success. The current study examines the extent to which cognition explains the relationship between literacy and retention of health information. Primary care patients aged 40 to 85 years watched a video about colorectal cancer (CRC) screening and then answered knowledge-based questions about the video's content as well as a literacy assessment and cognitive assessments measuring processing speed, working memory, and-long term memory. A week later, available participants completed the knowledge assessment a second time. In regression models for immediate knowledge, literacy significantly predicted knowledge. However, once cognition (i.e., processing speed, working memory, and long-term memory) was added to the model, it explained 70.7% of the relationship between literacy and performance. A week later, literacy again significantly predicted knowledge, but entering cognition into the model explained 45.9% of the relationship between literacy and performance. These results suggest that cognition explains much of the association between literacy and both immediate and delayed recall of health information. Design and intervention strategies for educational tools should consider cognitive factors such as working memory demands in addition to focusing on the readability of materials.

Severity of medial temporal atrophy and amnestic mild cognitive impairment: selecting type and number of memory tests

OBJECTIVE

Medial temporal lobe atrophy (MTA) can be used as a biomarker of pathology that affects mechanisms of episodic memory. The authors compared the strength of this biomarker with performance on four memory measures and examined the influence of demographic factors including age, level of education, and primary language (English or Spanish).

METHODS

The Hopkins Verbal Learning Test-revised, Fuld Object Memory Evaluation (FOME), delayed memory for a story passage, and delayed visual reproduction of the Wechsler Memory Scale-revised tests were administered to 281 subjects who were diagnosed as having no cognitive impairment, mild cognitive impairment (MCI), impaired non-MCI, or dementia. MTA scores were obtained from visual ratings of the hippocampus, entorhinal cortex, and perirhinal cortex on coronal magnetic resonance imaging scans using a magnetization-prepared rapid gradient echo protocol.

RESULTS

Age was associated with scores on all memory measures and MTA. Level of educational attainment had no influence on FOME performance but had greater associations with scores on other memory measures. In regression models, FOME scores had the strongest relationship with MTA scores, accounting for 31% of the explained variability. Among subjects with MCI, an index representing the total number of memory tests that were impaired was also predictive of the severity of MTA scores.

CONCLUSION

Among four common tests of memory, the FOME was highly associated with MTA, and it exhibited minimal influences of education. Impairment on more than one memory test was more predictive of MTA than impairment on a single memory test.

S-TOFHLA in mild Alzheimer's disease and Mild Cognitive Impairment patients as a measure of functional literacy: Preliminary study

The greatest difficulty in diagnosing cognitive loss in our population is the diversity of its education which has a broad spectrum ranging from illiteracy, functional illiteracy and different degrees of literacy, even in those with the same level of schooling.

Cognitive performance in community-dwelling English- and Spanish-speaking seniors

OBJECTIVES

to examine the association of language (English vs Spanish), and commonly used measures of memory and word fluency among older adults.

DESIGN

cross-sectional.

SETTING

community-based settings in New York City, including senior centres and residential complexes.

SUBJECTS

four hundred and twenty independently living adults aged 60 or older (mean 73.8 years).

METHODS

participants completed the Mini-Mental State Exam (MMSE), animal naming test (ANT) and Wechsler Memory Scale III (WMS) Story A immediate and delayed subtests. Scores were examined by strata of language, age or education and for different thresholds of the MMSE. We tested the association of language and cognitive test performance using multivariable linear regression.

RESULTS

twenty-one per cent of subjects were interviewed in Spanish and 16.2% reported poor-fair English proficiency. The mean WMS scores were not statistically different between English and Spanish groups (immediate recall, 9.9 vs 9.5, P = 0.44; delayed recall, 8.0 vs 7.6, P = 0.36, respectively), whereas ANT scores did differ (16.6 vs 14.3, P < 0.0001). These associations were consistent across MMSE thresholds. The association of language and ANT score was not significant after accounting for education.

CONCLUSIONS

we found little difference in performance on the Story A subtests from the WMS suggesting that this test may be used for both English- and Spanish-speaking populations. Results suggest that variations in ANT performance may be accounted for by adjusting for the level of education. These results have important implications for the generalisability of test scores among diverse older populations.

Literacy and learning in health care

The relationship between literacy and health outcomes are well documented in adult medicine, yet specific causal pathways are not entirely clear. Despite an incomplete understanding of the problem, numerous interventions have already been implemented with variable success. Many of those who proposed earlier strategies assumed the problem to originate from reading difficulties only. Given the timely need for more effective interventions, it is of increasing importance to reconsider the meaning of health literacy to advance our conceptual understanding of the problem and how best to respond. One potentially effective approach might involve recognizing the known associations between a larger set of cognitive and psychosocial abilities with functional literacy skills. Here we review the current health literacy definition and literature and draw on relevant research from the fields of education, cognitive science, and psychology. In this framework, a research agenda is proposed that considers an individual's "health-learning capacity," which refers to the broad constellation of cognitive and psychosocial skills from which patients or family members must draw to effectively promote, protect, and manage their own or a child's health. This new, related concept will lead, ideally, to more effective ways of thinking about health literacy interventions, including the design of health-education materials, instructional strategies, and the delivery of health care services to support patients and families across the life span.

Evidence for neurocognitive plasticity in at-risk older adults: the experience corps program

OBJECTIVE

To determine whether Experience Corps (EC), a social service program, would improve age-vulnerable executive functions and increase activity in brain regions in a high-risk group through increased cognitive and physical activity.

METHODS

Eight community-dwelling, older female volunteers and nine matched wait-list controls were recruited to serve in the ongoing EC: Baltimore program in three elementary schools. We employed functional magnetic resonance imaging (fMRI) preintervention and postintervention to examine whether EC volunteers improved executive function and showed increased activity in the prefrontal cortex relative to controls. fMRI volunteers were trained and placed with other volunteers 15 h/wk for 6 months during the academic year to assist teachers in kindergarten through third grade to promote children's literacy and academic achievement.

RESULTS

Participants were African American and had low education, low income, and low Mini-Mental State Examination scores (M = 24), indicative of elevated risk for cognitive impairment. Volunteers exhibited intervention-specific increases in brain activity in the left prefrontal cortex and anterior cingulate cortex over the 6-month interval relative to matched controls. Neural gains were matched by behavioral improvements in executive inhibitory ability.

CONCLUSIONS

Using fMRI, we demonstrated intervention-specific short-term gains in executive function and in the activity of prefrontal cortical regions in older adults at elevated risk for cognitive impairment. These pilot results provide proof of concept for use-dependent brain plasticity in later life, and, that interventions designed to promote health and function through everyday activity may enhance plasticity in key regions that support executive function.

Health literacy and cognitive performance in older adults

OBJECTIVES

To study the relationship between health literacy and memory and verbal fluency in older adults.

DESIGN

Cross-sectional cohort.

SETTING

Twenty senior centers and apartment buildings in New York, New York.

PARTICIPANTS

Independently living, English- and Spanish-speaking adults aged 60 and older (N=414).

MEASUREMENTS

Health literacy was measured using the Short Test of Functional Health Literacy in Adults (S-TOFHLA). The associations between S-TOFHLA scores and immediate and delayed recall (Wechsler Memory Scale II), verbal fluency (Animal Naming), and global cognitive function (Mini-Mental State Examination, MMSE) were modeled using multivariable logistic and linear regression.

RESULTS

Health literacy was inadequate in 24.3% of participants. Impairment of immediate recall occurred in 20.4%; delayed recall, 15.0%; verbal fluency, 9.9%; and MMSE, 17.4%. Abnormal cognitive function was strongly associated with inadequate health literacy: immediate recall (adjusted odds ratio (AOR)=3.44, 95% confidence interval (CI)=1.71-6.94, P<.001), delayed recall (AOR=3.48, 95% CI=1.58-7.67, P=.002), and verbal fluency (AOR=3.47, 95% CI=1.44-8.38, P=.006). These associations persisted in subgroups that excluded individuals with normal age-adjusted MMSE scores.

CONCLUSION

Memory and verbal fluency are strongly associated with health literacy, independently of education and health status, even in those with subtle cognitive dysfunction. Reducing the cognitive burden of health information might mitigate the detrimental effects of limited health literacy in older adults. Research that examines the effect of materials modified to older adults' cognitive limitations on health literacy and health outcomes is needed.

Cognitive reserve

The concept of reserve has been proposed to account for the disjunction between the degree of brain damage and its clinical outcome. This paper attempts to produce a coherent theoretical account the reserve in general and of cognitive reserve in particular. It reviews epidemiologic data supporting the concept of cognitive reserve, with a particular focus of its implications for aging and dementia. It then focuses on methodologic issues that are important when attempting to elucidate the neural underpinnings of cognitive reserve using imaging studies, and reviews some of our group's work in order to demonstrate these issues.

Health literacy skills of kidney transplant recipients

CONTEXT

Although low health literacy can affect patients' treatment decision making, comprehension of health information, and medication adherence, little is known about health literacy skills of kidney transplant recipients.

OBJECTIVE

To examine the relationship among kidney transplant recipients' health literacy levels, transplant knowledge, and graft function.

DESIGN

Cross-sectional study of 124 adult kidney transplant recipients.

MAIN OUTCOME MEASURES

Health literacy was assessed via the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Rapid Estimate of Adult Literacy in Medicine-Transplantation (REALM-T). Data on recipients' transplant numeracy, knowledge needs, and demographics were collected via semistructured interviews. Multivariable linear regressions were used to assess the relationship between health literacy and graft function.

RESULTS

Most kidney recipients (91%) had adequate health literacy (S-TOFHLA); however, 81% were unfamiliar with at least 1 kidney transplant-related term (REALM-T). The 5 least familiar terms were sensitization (50%), urethra (45%), trough level (41%), blood urea nitrogen (32%), and toxicity (31%). Numeracy levels varied: 21% knew the likelihood of 1-year graft survival; 29% knew that half of kidney recipients have problems with the transplant in the first 6 months; 68% were aware of the risk of death within the first year after transplantation; and 86% knew the normal range for creatinine in kidney recipients. Patients with lower health literacy (REALM-T) had higher creatinine levels.

CONCLUSIONS

Transplant providers should intervene with better patient education materials to improve patients' health literacy, which may improve patients' medication adherence or transplant outcomes.

Semantic verbal fluency in two contrasting languages

This cross-linguistic study investigated Semantic Verbal Fluency (SVF) performance in 30 American English-speaking and 30 Finnish-speaking healthy elderly adults with different cultural and linguistic backgrounds. Despite the different backgrounds of the participant groups, remarkable similarities were found between the groups in the overall SVF performance in two semantic categories (animals and clothes), in the proportions of words produced within the first half (30 seconds) of the SVF tasks, and in the variety of words produced for the categories. These similarities emerged despite the difference in the mean length of words produced in the two languages (with Finnish words being significantly longer than English words). The few differences found between the groups concerned the types and frequencies of the 10 most common words generated for the categories. It was concluded that culture and language differences do not contribute significantly to variability in SVF performance in healthy elderly people.

Prevalence rates for dementia and Alzheimer's disease in African Americans: 1992 versus 2001

BACKGROUND

This study compares age-specific and overall prevalence rates for dementia and Alzheimer's disease (AD) in two nonoverlapping, population-based cohorts of elderly African Americans in Indianapolis in 2001 and 1992.

METHODS

We used a two-stage design. The first stage involves the Community Screening Interview for Dementia (CSI-D). The CSI-D scores are grouped into good, intermediate, and poor performance before selection for clinical assessment. Diagnoses were performed using standard criteria in a consensus diagnosis conference; clinicians were blind to performance groups. In 1992, interviewers visited randomly sampled addresses to enroll self-identified African Americans aged > or =65 years. Of 2582 eligible, 2212 enrolled (9.6% refused, and 4.7% were too sick). In 2001, Medicare rolls were used for African Americans aged >70 years. Of 4260 eligible, 1892 (44%) enrolled, 1999 (47%) refused, and the remainder did not participate for other reasons.

RESULTS

The overall age-adjusted prevalence rate for dementia at age > or =70 years in 2001 was 7.45% (95 confidence interval [CI], 4.27-10.64), and in the 1992 cohort, this prevalence rate was 6.75% (95% CI, 5.77-7.74). The overall age-adjusted prevalence rate at age > or =70 years for AD in the 2001 cohort was 6.77% (95% CI, 3.65-9.90), and for the 1992 cohort, it was 5.47% (95% CI, 4.51-6.42). Rates for dementia and AD were not significantly different in the two cohorts (dementia, P = .3534; AD, P = .2649).

CONCLUSIONS

We found no differences in the prevalence rates of dementia and AD between 1992 and 2001, despite significant differences in medical history and medical treatment within these population-based cohorts of African American elderly.

Health Literacy Skills of Kidney Transplant Recipients

Context

Although low health literacy can affect patients' treatment decision making, comprehension of health information, and medication adherence, little is known about health literacy skills of kidney transplant recipients.

Objective

To examine the relationship among kidney transplant recipients' health literacy levels, transplant knowledge, and graft function.

Design

Cross-sectional study of 124 adult kidney transplant recipients.

Main Outcome Measures

Health literacy was assessed via the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Rapid Estimate of Adult Literacy in Medicine-Transplantation (REALM-T). Data on recipients' transplant numeracy, knowledge needs, and demographics were collected via semistructured interviews. Multivariable linear regressions were used to assess the relationship between health literacy and graft function.

Results

Most kidney recipients (91%) had adequate health literacy (S-TOFHLA); however, 81% were unfamiliar with at least 1 kidney transplant–related term (REALM-T). The 5 least familiar terms were sensitization (50%), urethra (45%), trough level (41%), blood urea nitrogen (32%), and toxicity (31%). Numeracy levels varied: 21% knew the likelihood of 1-year graft survival; 29% knew that half of kidney recipients have problems with the transplant in the first 6 months; 68% were aware of the risk of death within the first year after transplantation; and 86% knew the normal range for creatinine in kidney recipients. Patients with lower health literacy (REALM-T) had higher creatinine levels.

Conclusions

Transplant providers should intervene with better patient education materials to improve patients' health literacy, which may improve patients' medication adherence or transplant outcomes.

EXIT25 - Executive interview applied to a cognitively healthy elderly population with heterogeneous educational background

Education interferes with the performance in most cognitive tests, including executive function assessment.

Gender, resources across the life course, and cognitive functioning in Egypt

In this article, I evaluate the life-course determinants of cognitive functioning among 1,003 women and men aged 50 and older in Ismailia, Egypt. Three questions motivate this analysis: (1) Do older women have poorer cognitive functioning than do older men?; (2) Do cognitive resources accrued in childhood and adulthood have net positive associations with later-life cognitive functioning for women and men?; and (3) To what extent do differences in the amounts and effects of women's and men's cognitive resources account for gaps in their cognitive functioning? Compared with men, women have lower Modified-Mini Mental Status Exam (M-MMSE) scores for overall cognitive functioning. Cognitive resources in childhood and adulthood are jointly associated with the M-MMSE score. About 83% of the gender gap in mean M-MMSE scores is attributable to gaps in men's and women's attributes across the life course. Gender gaps in childhood cognitive resources-and especially schooling attainment-account for the largest share (18%) of the residual gender gap in cognitive functioning.

Neuropsychological, cognitive, and theoretical considerations for evaluation of bilingual individuals

As the number of bilinguals in the USA grows rapidly, it is increasingly important for neuropsychologists to be equipped and trained to address the unique challenges inherent in conducting ethical and competent neuropsychological evaluations with this population. Research on bilingualism has focused on two key cognitive mechanisms that introduce differences between bilinguals and monolinguals: (a) reduced frequency of language-specific use (weaker links), and (b) competition for selection within the language system in bilinguals (interference). Both mechanisms are needed to explain how bilingualism affects neuropsychological test performance, including the robust bilingual disadvantages found on verbal tasks, and more subtle bilingual advantages on some measures of cognitive control. These empirical results and theoretical claims can be used to derive a theoretically informed method for assessing cognitive status in bilinguals. We present specific considerations for measuring degree of bilingualism for both clients and examiners to aid in determinations of approaches to testing bilinguals, with practical guidelines for incorporating models of bilingualism and recent experimental data into neuropsychological evaluations. This integrated approach promises to provide improved clinical services for bilingual clients, and will also contribute to a program of research that will ultimately reveal the mechanisms underlying language processing and executive functioning in bilinguals and monolinguals alike.

Literacy affected ability to adequately discriminate among categories in multipoint Likert Scales

OBJECTIVES

To assess the effect of inability to read on a five-point Likert scale, using the WHOQOL-BREF response scale. It is hypothesized that inability to read is related to loss of discriminant power among the five-category response scale.

STUDY DESIGN AND SETTING

In a cross-sectional design, nonreaders (n=141) and subjects educated at a graduate level (n-907) were assessed. Statistical analyses combined classic and modern psychometric approaches (Confirmatory factor analysis and Rasch analysis).

RESULTS

There is a remarkable difference in the psychometric performance of items across the two subgroups. Fit indexes proved to be closer to the ideal for the graduate group, but not for the nonreader group. Reducing the number of response categories improved the model exclusively for the nonreader sample. Nonreaders do not interpret the scale as a true five-category scale, but exhibit a response pattern indicative that only three categories are in fact considered.

CONCLUSION

These results confirm the hypothesis that a multiple-category response scale is not suitable for nonreaders. They suggest that a simpler response scale should be adopted to achieve a more reliable and satisfactory psychometric performance in this population. This effect seems to be stronger when more abstract and subjective constructs are involved.

Challenges to the recognition and assessment of Alzheimer's disease in American Indians of the southwestern United States

Little is known about Alzheimer's disease (AD) and related neurodegenerative diseases in American Indian (AI) populations. To provide appropriate health care to elder AIs, whose population is expected to increase dramatically during the next 50 years, it is imperative to attain a better understanding of the interaction of culture and disease in this underserved population. Raising awareness in the AI population regarding the nature of dementia as it compares to normal aging and the development of culturally appropriate instruments to detect and stage AD are essential for future health care efforts. Barriers restricting clinical service to this population include historical factors relating to access to health care, cultural beliefs regarding aging, demographic diversity of the population, competing epidemiologic risk factors, and lack of proper assessment tools for clinicians.

Health literacy, cognitive abilities, and mortality among elderly persons

BACKGROUND

Low health literacy and low cognitive abilities both predict mortality, but no study has jointly examined these relationships.

METHODS

We conducted a prospective cohort study of 3,260 community-dwelling adults age 65 and older. Participants were interviewed in 1997 and administered the Short Test of Functional Health Literacy in Adults and the Mini Mental Status Examination. Mortality was determined using the National Death Index through 2003.

MEASUREMENTS AND MAIN RESULTS

In multivariate models with only literacy (not cognition), the adjusted hazard ratio was 1.50 (95% confidence of interval [CI] 1.24-1.81) for inadequate versus adequate literacy. In multivariate models without literacy, delayed recall of 3 items and the ability to serial subtract numbers were associated with higher mortality (e.g., adjusted hazard ratios [AHR] 1.74 [95% CI 1.30-2.34] for recall of zero versus 3 items, and 1.32 [95% CI 1.09-1.60] for 0-2 vs 5 correct subtractions). In multivariate analysis with both literacy and cognition, the AHRs for the cognition items were similar, but the AHR for inadequate literacy decreased to 1.27 (95% CI 1.03 - 1.57).

CONCLUSIONS

Both health literacy and cognitive abilities independently predict mortality. Interventions to improve patient knowledge and self-management skills should consider both the reading level and cognitive demands of the materials.

Alzheimer's disease in Down syndrome: neurobiology and risk

Down syndrome (DS) is characterized by increased mortality rates, both during early and later stages of life, and age-specific mortality risk remains higher in adults with DS compared with the overall population of people with mental retardation and with typically developing populations. Causes of increased mortality rates early in life are primarily due to the increased incidence of congenital heart disease and leukemia, while causes of higher mortality rates later in life may be due to a number of factors, two of which are an increased risk for Alzheimer's disease (AD) and an apparent tendency toward premature aging. In this article, we describe the increase in lifespan for people with DS that has occurred over the past 100 years, as well as advances in the understanding of the occurrence of AD in adults with DS. Aspects of the neurobiology of AD, including the role of amyloid, oxidative stress, Cu/ZN dismutase (SOD-1), as well as advances in neuroimaging are presented. The function of risk factors in the observed heterogeneity in the expression of AD dementia in adults with DS, as well as the need for sensitive and specific biomarkers of the clinical and pathological progressing of AD in adults with DS is considered.

Incorporating ethnicity into genetic risk assessment for Alzheimer disease: the REVEAL study experience

PURPOSE

To describe how investigators in a multisite randomized clinical trial addressed scientific and ethical issues involved in creating risk models based on genetic testing for African American participants.

METHODS

The following informed our decision whether to stratify risk assessment by ethnicity: evaluation of epidemiological data, appraisal of benefits and risks of incorporating ethnicity into calculations, and feasibility of creating ethnicity-specific risk curves. Once the decision was made, risk curves were created based on data from a large, diverse study of first-degree relatives of patients with Alzheimer disease.

RESULTS

Review of epidemiological data suggested notable differences in risk between African Americans and whites and that Apolipoprotein E genotype predicts risk in both groups. Discussions about the benefits and risks of stratified risk assessments reached consensus that estimates based on data from whites should not preclude enrolling African Americans, but population-specific risk curves should be created if feasible. Risk models specific to ethnicity, gender, and Apolipoprotein E genotype were subsequently developed for the randomized clinical trial that oversampled African Americans.

CONCLUSION

The Risk Evaluation and Education for Alzheimer Disease study provides an instructive example of a process to develop risk assessment protocols that are sensitive to the implications of genetic testing for multiple ethnic groups with differing levels of risk.

Language and Dementia: Neuropsychological Aspects

This article reviews recent evidence for the relationship between extralinguistic cognitive and language abilities in dementia. A survey of data from investigations of three dementia syndromes (Alzheimer's disease, semantic dementia and progressive nonfluent aphasia) reveals that, more often than not, deterioration of conceptual organization appears associated with lexical impairments, whereas impairments in executive function are associated with sentence- and discourse-level deficits. These connections between extralinguistic functions and language ability also emerge from the literature on cognitive reserve and bilingualism that investigates factors that delay the onset and possibly the progression of neuropsychological manifestation of dementia.

Patients' shame and attitudes toward discussing the results of literacy screening

We investigated patients' willingness to have their reading ability documented in their medical records and the degree of shame and embarrassment associated with such disclosure. Structured interviews were conducted among a consecutive sample of 283 primary care patients at an urban public hospital. Patients' literacy was measured using the Rapid Estimate of Adult Literacy in Medicine (REALM). Self-report of degree of shame and embarrassment related to literacy skills was measured using an orally administered questionnaire. Fifty-one percent of patients had low literacy skills (< or =sixth grade) and 27.9% were assessed as having marginal literacy (seventh-eighth grade). Half (47.6%) of patients reading at or below the third-grade level admitted feeling ashamed or embarrassed about their difficulties reading, compared with 19.2% of those reading at the fourth-sixth-grade level and 6.5% of those reading at the seventh-eighth-grade level (p < 0.001). More than 90% of patients with low or marginal literacy reported it would be helpful for the doctor or nurse to know they did not understand some medical words. Patients with limited literacy were more likely to report feelings of shame as a result of disclosure (p < 0.05). Health care providers must recognize the potential shame patients might experience as a result of literacy screening.

The elusive nature of executive functions: a review of our current understanding

Executive functions include abilities of goal formation, planning, carrying out goal-directed plans, and effective performance. This article aims at reviewing some of the current knowledge surrounding executive functioning and presenting the contrasting views regarding this concept. The neural substrates of the executive system are examined as well as the evolution of executive functioning, from development to decline. There is clear evidence of the vulnerability of executive functions to the effects of age over lifespan. The first executive function to emerge in children is the ability to inhibit overlearned behavior and the last to appear is verbal fluency. Inhibition of irrelevant information seems to decline earlier than set shifting and verbal fluency during senescence. The sequential progression and decline of these functions has been paralleled with the anatomical changes of the frontal lobe and its connections with other brain areas. Generalization of the results presented here are limited due to methodological differences across studies. Analysis of these differences is presented and suggestions for future research are offered.

Potential ethnic modifiers in the assessment and treatment of Alzheimer's disease: challenges for the future

OBJECTIVE

Despite numerous clinical trials, it is unknown whether ethnicity affects treatment response to cognitive enhancers in Alzheimer's disease (AD). There is convincing evidence of ethnic and genetic variability in drug metabolism. This article reviews the available data on ethnicity in clinical trials for AD to answer two questions: (1) what are the challenges to diagnose and treat AD across different ethnic groups, and (2) are there differences in response to pharmacologic interventions for AD across these different ethnic groups?

METHOD

Available data from Alzheimer's Disease Cooperative Study (ADCS) randomized controlled clinical trials and from randomized controlled industry-sponsored trials for four cognitive enhancers (donepezil, galantamine, rivastigmine and sabeluzole) were pooled to assess the numbers of non-Caucasian participants.

RESULTS

The participation of ethnic minority subjects in clinical trials for AD was dependent on the funding source, although Caucasian participants were over-represented and non-Caucasian participants were under-represented in the clinical trials. Because of the low participation rate of ethnic minorities, there were insufficient data to assess any differences in treatment outcome among different ethnic groups. Strategies to improve diversity in clinical trials are discussed.

CONCLUSION

Greater participation of ethnically diverse participants in clinical trials for AD would generate additional information on possible differences in metabolism, treatment response, adverse events to therapeutic agents, and could foster the investigation of genetic variability among ethnic groups.

Influence of premorbid IQ and education on progression of Alzheimer's disease

BACKGROUND

Lower education is associated with a higher risk of developing Alzheimer's disease (AD). Years of education and measures of general intellectual function (IQ) are highly correlated. It is important to determine whether there is a relationship between education and AD outcomes that is independent of IQ.

OBJECTIVE

To test the hypothesis that premorbid IQ is a stronger predictor of cognitive decline, global progression, and overall survival, than education in patients with AD.

METHODS

The study included 478 probable AD patients (322 women and 156 men, mean age 74.5 years) followed in a large AD referral center for a mean of 3.2 years. Eligible participants had a baseline estimate of premorbid IQ using the American version of the Nelson Adult Reading Test (AMNART) and at least one follow-up visit with complete neuropsychological assessment. We used random effects linear regression analysis, and Cox proportional hazards analysis to determine whether or not education and/or premorbid IQ were independently associated with cognitive decline, global progression of AD, and survival.

RESULTS

When the baseline AMNART score was included in regression models along with education and other demographic variables, AMNART score, but not education, was associated with a higher baseline score and slower rate of decline in MMSE and ADAS-Cog scores, and the Clinical Dementia Rating sum of boxes score. Neither higher premorbid IQ nor higher education was associated with longer survival.

CONCLUSIONS

We conclude that a baseline AMNART score is a better predictor of cognitive change in AD than education, but neither variable is associated with survival after diagnosis.

Cognitive reserve and Alzheimer disease

Epidemiologic evidence suggests that individuals with higher IQ, education, occupational attainment, or participation in leisure activities have a reduced risk of developing Alzheimer disease (AD). The concept of cognitive reserve (CR) posits that individual differences in how tasks are processed provide differential reserve against brain pathology or age-related changes. This may take 2 forms. In neural reserve, preexisting brain networks that are more efficient or have greater capacity may be less susceptible to disruption. In neural compensation, alternate networks may compensate for pathology's disruption of preexisting networks. Imaging studies have begun to identify the neural substrate of CR. Because CR may modulate the clinical expression of AD pathology, it is an important consideration in studies of "preclinical" AD and treatment studies. There is also the possibility that directly enhancing CR may help forestall the diagnosis of AD.

Cognitive Reserve and Alzheimer Disease

Epidemiologic evidence suggests that individuals with higher IQ, education, occupational attainment, or participation in leisure activities have a reduced risk of developing Alzheimer disease (AD). The concept of cognitive reserve (CR) posits that individual differences in how tasks are processed provide differential reserve against brain pathology or age-related changes. This may take 2 forms. In neural reserve, preexisting brain networks that are more efficient or have greater capacity may be less susceptible to disruption. In neural compensation, alternate networks may compensate for pathology's disruption of preexisting networks. Imaging studies have begun to identify the neural substrate of CR. Because CR may modulate the clinical expression of AD pathology, it is an important consideration in studies of "preclinical" AD and treatment studies. There is also the possibility that directly enhancing CR may help forestall the diagnosis of AD.