Cognitive performance in a high-functioning community-dwelling elderly population

The effects of aging and perceived loneliness on lexical ambiguity resolution

Language is central to the interactional nature of the social life within which it is situated. To react or respond in a particular situation, we must be able to recognize the social situation. Growing evidence has demonstrated the negative impact of perceived loneliness on late-life executive functions. Yet little is known about how social factors impact language processing for older people. The current study aims to fill this gap, first by assessing age-related changes in lexical processing during Chinese word reading, second, by examining whether older adults’ individual differences, such as processing speed and verbal abilities, modulate meaning retrieval and, third, by investigating whether perceived loneliness can hinder word reading. The use of compound words in Chinese enables significant sublexical ambiguity, requiring varying executive load during word recognition: when a word’s constituent characters carry multiple meanings, readers must consider the meaning contributions of both constituent characters and use top-down word information to determine the most accurate meaning of the ambiguous character, a process termed “sublexical ambiguity resolution.” In this study, adults read real Chinese words (including both sublexically ambiguous and unambiguous words) and pseudowords, and they were asked to make lexical decisions. Older adults exhibited greater lexicality effects (i.e., real words were easier to be identified than pseudowords) and similar sublexical ambiguity effects compared with young adults. Among older participants, processing speed could account for their ability to differentiate between words and pseudowords. In contrast, the level of perceived loneliness modulated the efficacy of sublexical ambiguity resolution: the participants with higher perceived loneliness displayed a greater sublexical ambiguity disadvantage effect. These results indicate that perceived loneliness may affect the use of contextual information in meaning retrieval during reading. The findings provide an important link between social connections and language processing.

Community support and promoting cognitive function for the elderly

Proper cognitive functions are critical to the life of the elderly. With the rapid aging of the population, community support plays an important role in cognitive functioning. This study examines the association between community support and the level of cognitive functioning in the elderly, and the mediating effect of social participation in the relationship. Based on the panel data of China Longitudinal Healthy Longevity Survey (CLHLS) in 2005, 2008, 2011, 2014, and 2018, people aged 65 and over are selected as the research object (N = 35,479). The panel Logit model is used to analyze the influence of community support on their cognitive functioning. In addition, the stepwise regression and KHB decomposition methods are used to test the influence mechanism of community support on their cognitive function. The benchmark regression results show that there is a significant correlation between community support and cognitive function in the elderly (OR: 1.64, 95% CI: 1.41–1.91, p < 0.01). Daily care (OR: 1.75, 95% CI: 1.33–2.29, p < 0.01) has the strongest impact on the cognitive function of the elderly, followed by health care (OR: 1.70, 95% CI: 1.43–2.01, p < 0.01) and legal support (OR: 1.64, 95% CI: 1.37–1.95, p < 0.01), while psychological care (OR: 1.62, 95% CI: 1.31–2.01, p < 0.01) has the weakest impact on the cognitive function of the elderly. The results of the mediation effect test show that social participation plays a significant intermediary role in the impact of community support on the cognitive function of the elderly (mediation percentage: 16.89%), demonstrating that community support can improve the cognitive function of the elderly by promoting the social participation of the elderly. In classified community support, social participation plays a significant intermediary role in the impact of psychological care on cognition (mediation percentage: 46.10%).

Differences in Subjective Memory Impairment, Depressive Symptoms, Sleep, and Physical Activity in African American and Asian American Elderly

Background: Subjective memory impairment (SMI) is associated with negative health outcomes including mild cognitive impairment and Alzheimer's disease. However, ethnic differences in SMI and disparities in risk factors associated with SMI among minority populations are understudied. The study examined the ethnic differences in SMI, whether SMI was associated with depressive symptoms, sleep, and physical activity (PA), and whether the associations vary across racial/ethnic groups. Methods: Participants included 243 African and Asian Americans (including Chinese, Vietnamese, and Korean Americans) aged 50 or older. Demographic information, SMI, depressive symptoms, daily sleeping hours, and PA levels were assessed. Results: Vietnamese Americans reported the highest SMI score. Depressive symptoms, sleeping hours, and PA levels were significantly associated with SMI. Depressive symptoms were the only significant factor across all ethnic groups. Significant interaction effects were found between ethnicity and health behaviors in predicting SMI. In particular, Vietnamese American participants with greater depressive symptoms and physical inactivity were significantly more likely to experience SMI compared to other ethnic groups Conclusions: Our findings demonstrate ethnic differences in SMI and its association with depressive symptoms, sleep, and PA, which highlight the importance of considering the unique cultural and historical backgrounds across different racial/ethnic groups when examining cognitive functioning in elderly.

Duration of Poverty and Subsequent Cognitive Function and Decline Among Older Adults in China, 2005-2018

OBJECTIVE

To investigate the relationship between late-life duration of poverty exposure and cognitive function and decline among older adults in China.

METHODS

Data were from 3,209 participants ≥64 years of age in the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Duration of poverty, defined according to urban and rural regional standards from the China Statistical Yearbook, was assessed according to annual household income from 2005 to 2011 (never in poverty; one-third of the period in poverty; two-thirds or more of the period in poverty). Cognitive function was measured by the Chinese Mini-Mental State Examination (CMMSE) from 2011 to 2018. We used attrition-weighted, multivariable mixed-effects Tobit regression to examine the association of duration of poverty with cognitive function and rate of decline.

RESULTS

A total of 1,162 individuals (36.21%) were never in poverty over the period from 2005 to 2011; 1,172 (36.52%) were in poverty one-third of the period; and 875 (27.27%) were in poverty two-thirds or more of the period. A longer poverty duration was associated with lower subsequent CMMSE scores with a dose-response relationship (one-third vs never in poverty: β = -0.98; 95% confidence interval -1.61 to -0.35; two-thirds or more vs never in poverty: β = -1.55; 95% confidence interval -2.29 to -0.81). However, a longer duration of poverty was associated with a slower rate of CMMSE score decline over time from 2011 to 2018.

CONCLUSION

These findings provide valuable evidence for the role of cumulative late-life poverty in relation to cognitive health among older adults in a rapidly urbanizing and aging middle-income country. Our findings may support a compensation hypothesis for cognitive reserve in this setting.

Associations between cognitive function, actigraphy-based and self-reported sleep in older community-dwelling adults: Findings from the Irish Longitudinal Study on Ageing

OBJECTIVE

Cognitive impairment is prevalent in older ages. Associations with sleep are well established; however, ambiguity remains in which sleep characteristics contribute to this impairment. We examined cross-sectional associations between both self-reported and actigraphy-based sleep and cognitive performance across a number of domains in community-dwelling older adults.

METHODS

1520 participants aged 50 and older with self-reported and actigraphy-based total sleep time (TST) (≤5, 6, 7-8, 9 and ≥10 h) and self-reported sleep problems were analysed. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), verbal fluency, immediate and delayed recall memory, colour trails tests, and choice reaction tests (CRT). Associations between sleep and cognition were modelled using linear and negative binomial regression.

RESULTS

Negative associations were found between ≥10 h of self-reported TST and MoCA error rate (incidence rate ratio [IRR] = 1.42; 95% confidence interval [CI] = 1.18, 1.71; p < 0.001); verbal fluency (beta [B] = -2.32 words; 95% CI = -4.00, -0.65; p < 0.01); and delayed recall (B = -0.91 words; 95% CI = -1.58, -0.25; p < 0.05) compared to 7-8 h. Significant associations with actigraphy-based TST were limited to MoCA error rate in ≤5 h (IRR = 1.22; 95% CI = 1.02, 1.45; p < 0.05) compared to 7-8 h. Higher numbers of sleep problems were associated with slower performance in CRT cognitive response time (IRR = 1.02; 95% CI = 1.00, 104; p < 0.05) and total response time (IRR = 1.02; 95% CI = 1.00, 1.04; p < 0.05).

CONCLUSIONS

Self-reported long sleep duration was consistently associated with worse cognitive performance across multiple domains. Marginal associations between cognition and both actigraphy-based sleep and self-reported sleep problems were also apparent. These results further affirm poor sleep as a risk factor for cognitive impairment.

Sensor-measured sedentariness and physical activity are differentially related to fluid and crystallized abilities in aging

Aerobic exercise and physical activity (PA) are known to benefit cognition in adulthood. However, a typical older adult spends most of the day sedentary or in light PA, behaviors that are typically poorly captured by questionnaires. To better understand the associations between time spent in different intensities of lifestyle PA and cognition, we measured average time spent daily in sedentariness, light, and moderate to vigorous PA using hip-worn sensors (ActiGraph accelerometers). We studied baseline data from 228 cognitively normal adults (Age 60-80) who took part in a clinical trial (clinical study identifier: NCT01472744). Fluid (processing speed, memory, and reasoning) and crystallized abilities (vocabulary knowledge) were assessed with the Virginia Cognitive Aging Battery. Adjusting for age, sex, and several modifiable socioeconomic, physical and functional health factors, time spent daily in moderate to vigorous PA was positively related with fluid abilities (perceptual speed and reasoning). Furthermore, we found that those spending more time sedentary performed better on vocabulary knowledge and reasoning tasks. In contrast, time spent in light PA was not related to either fluid or crystallized abilities. Our results add to the previous literature by providing the first sensor-based evidence that crystallized and fluid abilities in older age may be associated with engagement in different intensities of daily activity. Moreover, our findings suggest that the behavior of moderate to vigorous PA is at least as important in relation to cognition as the desirable long-term physiological effects of higher intensity PA and exercise. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Predictors of Working Memory Maintenance and Decline in Older Adults

The aging process is associated with the gradual decline of several cognitive functions, and working memory is particularly affected. Although the majority of older adults experience a deterioration of their working memory, some individuals maintain their working memory in older age, and some suffer an extreme deterioration of their working memory. The purpose of the present study was to identify, among a total of 120 potential predictors, those that significantly contributed to these two extreme outcomes in working memory. A sample of 588 healthy adults was examined with the n-back task in the spatial and verbal domains using a 2-back level of difficulty. Individuals were classified as working memory maintainers or decliners if their discrimination level in the two domains was superior to the 80th percentile or inferior to the 20th percentile, respectively. Logistic regression identified eight and six significant predictors of working memory maintenance and decline, respectively. High vocabulary scores and smoking more were significant predictors of working memory maintenance; however, in the opposite direction, these same variables predicted working memory decline. Several consumption habits that influenced cerebrovascular function were found in both models. Psychological traits and everyday activities were present in both models. We identified specific predictors that contribute to extremely high or low working memory performance in older age.

Stronger Functional Connectivity in the Default Mode and Salience Networks Is Associated With Youthful Memory in Superaging

"Superagers" are older adults who, despite their advanced age, maintain youthful memory. Previous morphometry studies revealed multiple default mode network (DMN) and salience network (SN) regions whose cortical thickness is greater in superagers and correlates with memory performance. In this study, we examined the intrinsic functional connectivity within DMN and SN in 41 young (24.5 ± 3.6 years old) and 40 older adults (66.9 ± 5.5 years old). Superaging was defined as youthful performance on a memory recall task, the California Verbal Learning Test (CVLT). Participants underwent a resting-state functional magnetic resonance imaging (fMRI) scan and performed a separate visual-verbal recognition memory task. As predicted, within both DMN and SN, superagers had stronger connectivity compared with typical older adults and similar connectivity compared with young adults. Superagers also performed similarly to young adults and better than typical older adults on the recognition task, demonstrating youthful episodic memory that generalized across memory tasks. Stronger connectivity within each network independently predicted better performance on both the CVLT and recognition task in older adults. Variation in intrinsic connectivity explained unique variance in memory performance, above and beyond youthful neuroanatomy. These results extend our understanding of the neural basis of superaging as a model of successful aging.

Cognitive Performance Among Older Persons in Japan and the United States

OBJECTIVE

To compare cognitive performance among Japanese and American persons, aged 68 years and older, using two nationally representative studies and to examine whether differences can be explained by differences in the distribution of risk factors or in their association with cognitive performance.

DESIGN

Nationally representative studies with harmonized collection of data on cognitive functioning.

SETTING

Nihon University Japanese Longitudinal Study of Aging and the US Health and Retirement Study.

PARTICIPANTS

A total of 1953 Japanese adults and 2959 US adults, aged 68 years or older.

MEASUREMENTS

Episodic memory and arithmetic working memory are measured using immediate and delayed word recall and serial 7s.

RESULTS

Americans have higher scores on episodic memory than Japanese people (0.72 points on a 20-point scale); however, when education is controlled, American and Japanese people did not differ. Level of working memory was higher in Japan (0.36 on a 5-point scale) than in the United States, and the effect of education on working memory was stronger among Americans than Japanese people. There are no differences over the age of 85 years.

CONCLUSION

Even with large differences in educational attainment and a strong effect of education on cognitive functioning, the overall differences in cognitive functioning between the United States and Japan are modest. Differences in health appear to have little effect on national differences in cognition. J Am Geriatr Soc 68:354-361, 2020.

Predictors of Source Memory Success and Failure in Older Adults

Source memory decline has been identified as one of the types of memory most seriously affected during older age. It refers to our capacity to recollect the contextual information in which our experiences take place. Although most elderly adults will be affected by progressive source memory decline, a subset of individuals will not follow this average pattern; instead, their source memory capabilities will remain functional. Likewise, a minority of individuals will manifest an extreme decay of their source memory abilities. The objective of the present study was to identify among 120 potential predictors that significantly contributed to these two extreme source memory outcomes. Spatial source memory was measured in a sample of 519 healthy individuals between 61 and 80 years old. Individuals who performed below the 20th and above the 80th percentiles in the source memory task were defined as individuals whose episodic memory failed and succeeded, respectively. Logistic models identified five and six significant predictors of source memory success and failure in older age, respectively. High source memory performance was mainly predicted by healthy cardiovascular markers and psychological traits, whereas low source memory performance was primarily predicted by consumption habits and by less engagement in mental activities. The models identified relevant biological and life experiences that underlie these unusual source memory outcomes in older age.

Nutritional Status and Cognitive Impairment among the Very Old in a Community Sample from Southern Brazil

OBJECTIVE

To determine which factors, especially those related to nutrition, are associated with cognitive function in the oldest old, here considered those at least 80 years of age.

DESIGN

A cross-sectional, population-based study.

SETTING

Veranópolis, Rio Grande do Sul, Brazil, and surrounding rural areas.

PARTICIPANTS

Individuals aged 80 years and older.

MEASUREMENTS

The Mini Nutritional Assessment, anthropometric measurements, and serum levels of albumin and vitamin B12 were associated with cognitive function according to the Mini Mental State Examination (MMSE) and the Clock Drawing Test (CDT). Socio-demographic data were obtained through a structured questionnaire. Multivariate analysis was used to determine the associations.

RESULTS

According to the MMSE and the CDT, the prevalence of cognitive impairment was 47.7% [95%CI 39.7-55.7] and 58.2% [95%CI 50.3-66.1], respectively. In the adjusted analysis, the only positive linear association with MMSE scores indicating cognitive impairment was age. However, CDT scores indicating cognitive impairment were five times higher among those with low serum vitamin B12 concentrations. For the other variables, there was a positive association between age, being widowed, a low educational level and central nervous system drugs. Being single, living with children and living alone were protective factors for cognitive impairment.

CONCLUSIONS

Although cognitive impairment was positively associated with old age, being widowed and low educational level in this population, the only nutritional variable positively associated with cognitive impairment was a low vitamin B12 concentration.

Hospitalisation and surgery: are there hidden cognitive consequences? Evidence from The Irish Longitudinal study on Ageing (TILDA)

Background

the dramatic shift in the global population demographic has led to increasing numbers of older people undergoing hospitalisation and surgical procedures.

Objectives

to determine whether hospitalisation or hospitalisation with surgery under general anaesthesia is associated with poorer cognitive performance in adults over the age of 50.

Methods

cognitive function in the domains of global cognition, memory and executive function was assessed in 8,023 individuals at waves 1 and 2 of The Irish Longitudinal Study on Ageing (TILDA), 2 years apart. Mixed-effects models were used to investigate the hypothesis after adjustment for risk factors for cognitive decline and potential confounders.

Results

during the 12 months preceding wave 1, 472 participants were hospitalised (mean age 67.0, 54.9% female) and a further 560 participants (mean age 64.6, 52.1% female) were hospitalised and underwent surgery with general anaesthesia; 6,938 (mean age 63.5, 54.5% female) were not hospitalised. There was a 14% higher error rate (IRR[95% CI] = 1.14[1.06, 1.22]) in the MMSE in the hospitalisation group and a 6% higher error rate (IRR[95% CI] = 1.06[0.99, 1.13]) in the surgery group compared to those with no hospitalisation. Poorer cognitive performance in the memory tasks was evident in both hospitalisation and hospitalisation with surgery groups (immediate recall: [95% CI] = -0.13 words[-0.22,-0.04] versus -0.13 words[-0.21,-0.04] and delayed recall: -0.20 words[-0.33,-0.06] versus -0.20[-0.32, -0.07]) compared to those with no hospitalisation. Increased error in the time-based prospective memory task was observed in the hospitalisation group and the surgery group (OR[95% CI] = 1.32[1.08, 1.60] versus 1.29[1.07, 1.55]).

Conclusion

hospitalisation and hospitalisation with surgery and general anaesthesia are associated with poorer global and domain specific cognitive performance.

Self-Efficacy and Cognitive Performance in High-Functioning Older Individuals

The hypothesis that stronger self-efficacy beliefs are associated with better cognitive performance at older ages was examined in a sample of men and women, age 70-79. Multiple domains of efficacy beliefs and cognitive abilities were examined. Analyses revealed considerable specificity in the observed associations. For men, multiple regression analyses revealed that instrumental efficacy beliefs were related to better performance on tests of memory and abstraction, independent of sociodemographic characteristics and physical and psychological health; there were no independent associations with individual tests of spatial ability naming, incidental recall, or delayed spatial recognition. For women, instrumental efficacy beliefs had no significant associations with the tests of cognitive ability. Interpersonal efficacy beliefs showed no significant associations for men or women. Possible reasons for these gender differences as well as the specificity of the instrumental efficacy associations are discussed.

Action Video Game Training for Healthy Adults: A Meta-Analytic Study

Action video game (AVG) has attracted increasing attention from both the public and from researchers. More and more studies found video game training improved a variety of cognitive functions. However, it remains controversial whether healthy adults can benefit from AVG training, and whether young and older adults benefit similarly from AVG training. In the present study, we aimed to quantitatively assess the AVG training effect on the cognitive ability of adults and to compare the training effects on young and older adults by conducting a meta-analysis on previous findings. We systematically searched video game training studies published between January 1986 and July 2015. Twenty studies were included in the present meta-analysis, for a total of 313 participants included in the training group and 323 participants in the control group. The results demonstrate that healthy adults achieve moderate benefit from AVG training in overall cognitive ability and moderate to small benefit in specific cognitive domains. In contrast, young adults gain more benefits from AVG training than older adults in both overall cognition and specific cognitive domains. Age, education, and some methodological factors, such as the session duration, session number, total training duration, and control group type, modulated the training effects. These meta-analytic findings provide evidence that AVG training may serve as an efficient way to improve the cognitive performance of healthy adults. We also discussed several directions for future AVG training studies.

Age-related changes in dentate gyrus cell numbers, neurogenesis, and associations with cognitive impairments in the rhesus monkey

The generation of new neurons in the adult mammalian brain is well-established for the hippocampal dentate gyrus (DG). However, the role of neurogenesis in hippocampal function and cognition, how it changes in aging, and the mechanisms underlying this are yet to be elucidated in the monkey brain. To address this, we investigated adult neurogenesis in the DG of 42 rhesus monkeys (39 cognitively tested) ranging in age from young adult to the elderly. We report here that there is an age-related decline in proliferation and a delayed development of adult neuronal phenotype. Additionally, we show that many of the new neurons survive throughout the lifetime of the animal and may contribute to a modest increase in total neuron number in the granule cell layer of the DG over the adult life span. Lastly, we find that measures of decreased adult neurogenesis are only modestly predictive of age-related cognitive impairment.

Education Desegregation and Cognitive Change in African American Older Adults

OBJECTIVES

The present study examined the relationship between desegregated schooling and cognitive change in a sample of 420 community-dwelling African American elders (mean age = 68.6; SD = 9.1).

METHOD

Participants were recruited for the Baltimore Study of Black Aging - Patterns of Cognitive Aging. Cognitive measures from six domains of function were administered at baseline and follow-up 33 months later. Repeated measures multivariate analysis of covariance was conducted; the between subjects factors were schooling type and age cohort, and the within subjects factor was time. Analyses controlled for age, years of education, and sex, and follow-up univariate analyses were used to determine which individual cognitive scores drove the multivariate effects.

RESULTS

There were significant multivariate within-group, between-group, and interaction effects (p < .05). Univariate analyses indicated that the desegregated schooling group scored significantly better on Language and Perceptual Speed (p < .01), and the youngest age cohort (50- to 59-year-olds) performed better on measures of Perceptual Speed. There were no significant univariate interactions between schooling group or age cohort and cognitive change over time.

DISCUSSION

Overall, these findings suggest a slight advantage of desegregated schooling for cognitive performance, but no advantage of desegregated schooling on the rate of cognitive change over time in this sample.

Correlates of above-average cognitive performance among older adults: the SABE study

This study aimed to identify factors associated with optimal global cognitive performance among older adults in the city of Sao Paulo, Brazil. A cross-sectional study was carried out with a sample of community-dwelling older adults who participated in the SABE Study (Health, Well-Being and Ageing) in 2006. The dependent variable was cognitive performance, categorized as “normal” or “optimal”. The independent variables were socio-demographic data, lifestyle and health conditions. Data analysis involved descriptive statistics, followed by multiple logistic regression (significance set at 5%). Optimal cognitive performance was found in 28.4% of the sample, representing 730,051 older adults. Optimal performance was associated with a younger age, a report of no difficulties regarding instrumental activities of daily living, non-abusive alcohol intake, self-rated income sufficient to meet one’s daily needs and contact with family and friends. Optimal cognitive performance among older adults is associated with conditions favoring participation and independence.

Clinical, physical and lifestyle variables and relationship with cognition and mood in aging: a cross-sectional analysis of distinct educational groups

It is relevant to unravel the factors that may mediate the cognitive decline observed during aging. Previous reports indicate that education has a positive influence on cognitive performance, while age, female gender and, especially, depressed mood were associated with poorer performances across multiple cognitive dimensions (memory and general executive function). Herein, the present study aimed to characterize the cognitive performance of community-dwelling individuals within distinct educational groups categorized by the number of completed formal school years: “less than 4,” “4, completed primary education,” and “more than 4.” Participants (n = 1051) were randomly selected from local health registries and representative of the Portuguese population for age and gender. Neurocognitive and clinical assessments were conducted in local health care centers. Structural equation modeling was used to derive a cognitive score, and hierarchical linear regressions were conducted for each educational group. Education, age and depressed mood were significant variables in directly explaining the obtained cognitive score, while gender was found to be an indirect variable. In all educational groups, mood was the most significant factor with effect on cognitive performance. Specifically, a depressed mood led to lower cognitive performance. The clinical disease indices cardiac and stroke associated with a more negative mood, while moderate increases in BMI, alcohol consumption and physical activity associated positively with improved mood and thus benefitted cognitive performance. Results warrant further research on the cause-effect (longitudinal) relationship between clinical indices of disease and risk factors and mood and cognition throughout aging.

Race-related disparities in 5-year cognitive level and change in untrained ACTIVE participants

OBJECTIVE

The current study examined a 5-year cognitive change in untrained African American and White participants from the Advanced Cognitive Training in Independent and Vital Elderly (ACTIVE) study.

METHOD

Five-year trajectories of memory, reasoning, visual processing speed/useful field of view, digit-symbol substitution, and vocabulary were investigated. Education, health, gender, age, and retest/practice effects were controlled for, and a missing data pattern mixture approach was used to adjust for dropout effects.

RESULTS

After considering age, education, health, and gender, being African American uniquely explained 2% to 7% of the variance in cognitive performance. There were virtually no significant race differences in the rates of change.

DISCUSSION

Race-related results in the current study are consistent with previous research suggesting that social advantage factors such as education have a stronger influence on the level of performance than the rate of change. The small remaining effects of being African American on performance levels likely reflect uncontrolled variation in factors like literacy and financial advantage.

Hippocampal network connections account for differences in memory performance in the middle-aged rhesus monkey

Recent neurophysiological and functional neuroimaging studies suggest that the memory decline found with normal aging is not solely due to regional disruptions in the hippocampus, but also is brought about by alterations in the functional coupling between the hippocampus and long-distance neocortical regions. However, the anatomical basis for this functional "dyscoupling" has not been fully revealed. In this study, we applied a multimodal magnetic resonance imaging technique to noninvasively examine the large-scale anatomical and functional hippocampal network of a group of middle aged rhesus monkeys. Using diffusion spectrum imaging, we have found that monkeys with lower memory performance had weaker structural white matter connections between the hippocampus and neocortical association areas. Resting state functional imaging revealed somewhat of an opposite result. Monkeys with low memory performance displayed elevated coupling strengths in the network between the hippocampus and the neocortical areas. Taken together with recent findings, this contradictory pattern may be the result of either underlying physiological burden or abnormal neuronal decoupling due to the structural alterations, which induce a neuronal compensation mechanism for the structural loss or interference on task related neuronal activation, respectively.

Carotid intima-media thickness is associated with cognitive deficiency in hypertensive patients with elevated central systolic blood pressure

Background

The role of hypertension in the loss of cognitive function is controversial. Relationships between hypertension and increases in cerebral vascular resistance, diffused lesions and multiple lacunar infarcts of the white matter are well known. Thus, the objectives of this study were: to evaluate the relationship between hypertension and cognitive dysfunction (CD), identify risk factors and determine the association between early markers of vascular disease and CD in hypertensive individuals.

Methods

Two hundred individuals aged between 40 and 80 years old were evaluated in this cross-sectional prospective study. Fifty participants were controls (CT). The remaining 150 hypertensive patients were subdivided into two groups, those with CD (HCD) and those without CD (HNCD). All participants underwent clinical evaluations and biochemical blood tests were performed. CD was investigated using the Mini Mental State Examination (MMSE) following the guidelines for its use in Brazil. The impact of hypertension on the arterial bed was assessed by identifying and measuring changes in the intima-media thickness (IMT) by vascular ultrasonography of the carotid arteries and analyses of the central blood pressure and Augmentation Index by applanation tonometry of the radial artery.

Results

There were no significant differences in the total cholesterol, high-density lipoprotein cholesterol and triglycerides plasma concentrations between the three groups. The serum creatinine and estimated glomerular filtration rate were within normal ranges for all three groups. A significantly lower MMSE score was recorded for the HCD Group compared to the HNCD and CT Groups (p-value < 0.05).

The IMT was significantly different between the HNCD and HCD Groups (p-value = 0.0124). A significant difference in the IMT was also observed between hypertensive patients and the CT Group (p-value < 0.0001). Age, low-density cholesterol, high-density cholesterol, triglycerides and IMT increased the Odds Ratio for cognitive dysfunction.

The central systolic pressure was significantly higher in the HCD and HNCD Groups compared to CT Group (p-value < 0.0001).

Conclusions

Hypertensive patients with CD have changes in the vascular morphology characterized by an increased carotid IMT, enhanced atherosclerotic lipid profile and impaired hemodynamic functional manifested by elevated central systolic blood pressure.

Neuronal and morphological bases of cognitive decline in aged rhesus monkeys

Rhesus monkeys provide a valuable model for studying the basis of cognitive aging because they are vulnerable to age-related decline in executive function and memory in a manner similar to humans. Some of the behavioral tasks sensitive to the effects of aging are the delayed response working memory test, recognition memory tests including the delayed nonmatching-to-sample and the delayed recognition span task, and tests of executive function including reversal learning and conceptual set-shifting task. Much effort has been directed toward discovering the neurobiological parameters that are coupled to individual differences in age-related cognitive decline. Area 46 of the dorsolateral prefrontal cortex (dlPFC) has been extensively studied for its critical role in executive function while the hippocampus and related cortical regions have been a major target of research for memory function. Some of the key age-related changes in area 46 include decreases in volume, microcolumn strength, synapse density, and α1- and α2-adrenergic receptor binding densities. All of these measures significantly correlate with cognitive scores. Interestingly, the critical synaptic subtypes associated with cognitive function appear to be different between the dlPFC and the hippocampus. For example, the dendritic spine subtype most critical to task acquisition and vulnerable to aging in area 46 is the thin spine, whereas in the dentate gyrus, the density of large mushroom spines with perforated synapses correlates with memory performance. This review summarizes age-related changes in anatomical, neuronal, and synaptic parameters within brain areas implicated in cognition and whether these changes are associated with cognitive decline.

The relationship between computer experience and computerized cognitive test performance among older adults

OBJECTIVE

This study compared the relationship between computer experience and performance on computerized cognitive tests and a traditional paper-and-pencil cognitive test in a sample of older adults (N = 634).

METHOD

Participants completed computer experience and computer attitudes questionnaires, three computerized cognitive tests (Useful Field of View (UFOV) Test, Road Sign Test, and Stroop task) and a paper-and-pencil cognitive measure (Trail Making Test). Multivariate analysis of covariance was used to examine differences in cognitive performance across the four measures between those with and without computer experience after adjusting for confounding variables.

RESULTS

Although computer experience had a significant main effect across all cognitive measures, the effect sizes were similar. After controlling for computer attitudes, the relationship between computer experience and UFOV was fully attenuated.

DISCUSSION

Findings suggest that computer experience is not uniquely related to performance on computerized cognitive measures compared with paper-and-pencil measures. Because the relationship between computer experience and UFOV was fully attenuated by computer attitudes, this may imply that motivational factors are more influential to UFOV performance than computer experience. Our findings support the hypothesis that computer use is related to cognitive performance, and this relationship is not stronger for computerized cognitive measures. Implications and directions for future research are provided.

Association between apolipoprotein E ε4 and longitudinal cognitive decline: nested case-control study among chinese community-dwelling elders

BACKGROUND/AIMS

Cognitive decline in the elderly is an early predictor of dementia. The apolipoprotein E (APOE) ε4 allele is considered an important genetic determinant of Alzheimer's disease (AD), and strongly suspected to play a role in cognitive variation. However, its effects upon predicting the progression of cognitive decline more generally remain unclear. Our aim was to explore the role of APOE ε4 in longitudinal cognitive decline, considering sociodemographics, vascular disease, and lipid profile.

METHODS

We chose a nested case-control design, and prospectively collected demographic and clinical data, determined APOE genotypes, and obtained follow-up information on cognitive variation (measured by a spectrum of cognitive tests) for 3 years. Cognitive decline was predefined as an increase in Clinical Dementia Rating Scale class, or at least a 4-point decrease (>1 SD) in MMSE, between baseline and follow-ups.

RESULTS

Among 600 follow-up subjects with mild cognitive impairment and aged 65 years or older, 114 pairs of cognitive decline and stable subjects were identified and matched for sex, age, and educational level in a 1:1 ratio. The APOE ε4 frequency in the cognitive decline group was significantly higher than that in the stable group (p < 0.05), while the APOE ε2 and ε3 prevalence in the cognitive decline group did not differ significantly from that in controls (p > 0.05). At the first follow-up, modest but significant declines only in the memory domain were associated with APOE ε4. At the last follow-up, significant associations were noted between APOE ε4 and cognitive decline from 5 of the 6 cognitive outcomes, which included story recall, memory, spatial recognition, naming, and sustained attention. Conditional logistic regression showed that the presence of APOE ε4 was significantly associated with the cognitive decline group, as compared to the stable group, adjusting for vascular diseases and lipid profile.

CONCLUSIONS

APOE ε4 offered information on the risk of cognitive decline in this longitudinal study, and may exert detectable effects early in a long prodromal AD trajectory.

Do the effects of APOE-ε4 on cognitive function and decline depend upon vitamin status? MacArthur Studies of Successful Aging

OBJECTIVES

To investigate whether gene nutrient interactions influence the risk of cognitive dysfunction among older persons.

DESIGN

We performed a cross-sectional and longitudinal study of 499 adults aged 70-79 years from the Mac Arthur Study of Successful Aging to determine the effect of apolipoprotein E (APOE) in conjunction with plasma levels of homocysteine and of the related B vitamins on multiple domains of cognitive function and cognitive decline.

RESULTS

The APOE-ε4 allele, high homocysteine, low folate, and low vitamin B6 levels were each associated with worse baseline cognitive function, and all but B6 and B12 were associated with seven year cognitive decline. There was no interaction between APOE-ε4, and homocysteine, folate, B6, or B12 in predicting baseline cognitive function (p-values: 0.12-0.94) or longitudinal decline (p-values: 0.52-0.91). Of five cognitive subtests, there was a significant interaction between the ε4 allele, low B6, and decline in correct naming response items (p=0.04).

CONCLUSION

B vitamin status does not influence the risk of overall cognitive dysfunction in ε4 allele affected older adults.

Race-related cognitive test bias in the active study: a mimic model approach

The present study investigated evidence for race-related test bias in cognitive measures used in the baseline assessment of the ACTIVE clinical trial. Test bias against African Americans has been documented in both cognitive aging and early life span studies. Despite significant mean performance differences, Multiple Indicators Multiple Causes (MIMIC) models suggested most differences were at the construct level. There was little evidence that specific measures put either group at particular advantage or disadvantage and little evidence of cognitive test bias in this sample. Small group differences in education, cognitive status, and health suggest positive selection may have attenuated possible biases.

Differential item functioning of the Boston Naming Test in cognitively normal African American and Caucasian older adults

Scores on the Boston Naming Test (BNT) are frequently lower for African American when compared with Caucasian adults. Although demographically based norms can mitigate the impact of this discrepancy on the likelihood of erroneous diagnostic impressions, a growing consensus suggests that group norms do not sufficiently address or advance our understanding of the underlying psychometric and sociocultural factors that lead to between-group score discrepancies. Using item response theory and methods to detect differential item functioning (DIF), the current investigation moves beyond comparisons of the summed total score to examine whether the conditional probability of responding correctly to individual BNT items differs between African American and Caucasian adults. Participants included 670 adults age 52 and older who took part in Mayo's Older Americans and Older African Americans Normative Studies. Under a two-parameter logistic item response theory framework and after correction for the false discovery rate, 12 items where shown to demonstrate DIF. Of these 12 items, 6 ("dominoes," "escalator," "muzzle," "latch," "tripod," and "palette") were also identified in additional analyses using hierarchical logistic regression models and represent the strongest evidence for race/ethnicity-based DIF. These findings afford a finer characterization of the psychometric properties of the BNT and expand our understanding of between-group performance.

Norms for the Mini-Mental State Examination from a sample of Sri Lankan older people

OBJECTIVE

To derive norms for the Mini Mental State Examination (MMSE) based on age, gender and level of formal education among the elderly in Sri Lanka.

METHOD

A validated Sinhalese version of the MMSE was administered to people aged 55 years and above residing in 14 randomly selected elders' homes. Effects of age, gender and level of formal education on MMSE scores were compared using multiple linear regression analysis.

RESULTS

A total of 446 subjects [male/female = 136/320] formed the final sample. Level of education and gender exerted a significant influence on MMSE scores, but not age. The median and 10th percentile scores on the Sinhalese MMSE for the education groups were as follows: education <5 years = 19 and 12; education >5 years = 24 and 16, respectively.

CONCLUSION

The findings confirm the influence of level of education on MMSE scores among the elderly living in care homes in Sri Lanka, and suggest that education stratified cut-off scores should be used while screening for cognitive impairment in this population.

Inflammation and rate of cognitive change in high-functioning older adults

BACKGROUND

Inflammatory proteins including interleukin-6 (IL-6) and C-reactive protein (CRP) have been associated with incident cognitive impairment, but little research has addressed their effects on the rate of cognitive change, and findings are mixed. The purpose of this study was to examine the relationship between serum levels of IL-6 and CRP and the rate of cognitive change across a range of cognitive domains in a sample of healthy older persons.

METHODS

Growth curve analysis was performed on data from the MacArthur Study of Successful Aging, a longitudinal cohort study of high-functioning older adults aged 70-79 years at baseline in 1988 and reinterviewed in 1991 and 1995 (N = 851). Individual growth curve parameters were derived from baseline and follow-up performance in abstraction, language, spatial ability, verbal recall, spatial recognition, and global cognitive function based on age, IL-6, CRP, and covariates.

RESULTS

Cross-sectionally, there is a generally linear negative relationship between inflammation and cognition, such that higher levels of inflammation are associated with lower levels of baseline cognitive function. After controlling for potential confounders, there was no effect of inflammation on baseline cognitive function or the rate of longitudinal cognitive change. However, persons in the top tertile on IL-6 were at an increased risk of incident declines on the Short Portable Mental Status Questionnaire (SPMSQ).

CONCLUSIONS

Although high levels of inflammation are associated with incident cognitive impairment, these results do not generalize to the full range of cognitive changes, where the role of inflammation appears to be marginal.

The Apartment Test: validity of a memory measure

The Memory in Reality (MIR) test, or Apartment Test, was designed as an ecologically valid alternative to word list recall measures. Participants name 10 everyday objects, place them in a scale model of an apartment and after a delay with interference, recall the objects and their placement. Two studies are reported. Study 1 included 51 older adult volunteers. Study 2 was a population-based sample of 633 older twins. The Apartment Test Recall and Placement tasks were highly correlated with word list delayed recall. Ecological validity was supported by correlations with informant reports of participants' functioning. Apartment Test Recall was not affected by education. Analysis of Receiver Operating Characteristics (ROC) showed Apartment Test Recall performed as well as word list delayed recall in distinguishing participants with and without dementia. We conclude that the Apartment Test is a valid measure of verbal memory with evidence of ecological and concurrent validity.

Characterizing and explaining differences in cognitive test performance between african american and European American older adults

The present study examined differences in cognitive performance of African American and European American older adults on cognitive and intellectual measures, and the extent to which literacy status or reading level was useful in explaining these group differences. African American elders performed more poorly than European American elders on 12 of 13 cognitive tests administered, p < .05. After controlling for reading level achievement, differences in performance became nonsignificant for 5 of these 12 tests. Nonetheless, some differences persisted, suggesting that other potential mediators of race differences remain to be explored in future research.

Memory impairment among primary care veterans

Memory impairment is the most frequent cognitive dysfunction for older patients. Though studies have shown that dementia is often overlooked in primary care settings, there has been minimal focus specifically on memory impairment, on patients' concerns about memory, or their desire to address these concerns. The objectives of this study were to (1) investigate the prevalence of memory impairment among patients without dementia diagnoses, (2) determine the degree of patients' concern about memory impairment and (3) identify other patient characteristics associated with memory impairment among older primary care patients. Using telephone versions of a four-item memory test and proxy-reported cognitive decline for patients unable to complete interviews, we performed memory assessment of randomly selected patients, 75 years and older, without dementia diagnoses who see primary care physicians at least twice every six months. Among 260 patients and 20 proxies, 19.8% had memory impairment at a level indicative of probable dementia. Adjusting for age, ethnicity, and education, subjects who were more concerned about memory impairment were more likely to be impaired. (Adjusted odds ratio [AOR]: 1.4 (for each additional level of concern); 95% confidence interval [CI]: (1.0-2.0)). Similarly, subjects wanting their physician to discuss with them their memory concerns were more likely to be impaired (AOR: 1.4; 95% CI: 1.0-1.9). Memory impairment is common among older primary care patients without diagnosed dementia. Knowing patients' concerns about memory impairment and their desire to discuss these concerns may facilitate cognitive screening in this setting.

Depressive symptoms as a predictor of cognitive decline: MacArthur Studies of Successful Aging

OBJECTIVE

The prevalence of dementia continues to rise, and yet, there are few known modifiable risk factors. Depression, as a treatable condition, may be important in the development of dementia. Our objective was to examine the association between depressive symptoms and longitudinal cognitive changes in older adults who were high-functioning at baseline.

METHODS

The authors analyzed data from a community-based cohort (aged 70-79 at baseline), who, at study entry, scored 7 or more (out of 9) on the Short Portable Mental Status Questionnaire (SPMSQ). Depressive symptoms were assessed at baseline using the depression subscale of the Hopkins Symptom Check List. Cognitive performance was measured at baseline and at seven-year follow up by the SPMSQ and by summary scores from standard tests of naming, construction, spatial recognition, abstraction, and delayed recall.

RESULTS

After adjusting for potential confounders, including age, education, and chronic health conditions such as diabetes, heart attack, stroke, and hypertension, a higher number of baseline depressive symptoms were strongly associated with greater seven-year decline in cognitive performance and with higher odds of incident cognitive impairment, i.e., decline in SPMSQ score to < or = 6 (adjusted odds ratio per quartile of depressive symptoms score: 1.34, 95% confidence interval: 1.10-1.68).

CONCLUSIONS

Depressive symptomatology independently predicts cognitive decline and incident cognitive impairment in previously high-functioning older persons.

Cognitive and Non-Cognitive Factors Contributing to the Longitudinal Identification of Successful Older Adults in theBetulaStudy

Studies of successful aging have typically defined elderly who fall in the upper end of a distribution of test scores as successful. A different definition of successful aging requires that older adults fall at or above the mean level of younger adults and maintain this level over time. Here we examined this definition of successful aging in a sample of 1463 individuals between the ages of 50 of 85. Based on principal coordinate analysis of cognitive and non-cognitive variables, we identified a group of 55 (8.3%) 70-85 years olds that were high functioning. This group of elderly showed elevated performance on a range of cognitive tasks. Non-cognitive factors that characterized this group included education and subjective health. The participants were retested 5 years later and the same type of analysis was repeated. Of the remaining individuals who initially were classified as high functioning, 18 (35%) remained high functioning and thus met the definition for successful aging. Years of education was a significant predictor of who remained successful over time.

Menopause Transition Stage and Endogenous Estradiol and Follicle-Stimulating Hormone Levels are Not Related to Cognitive Performance: Cross-Sectional Results from the Study of Women's Health across the Nation (SWAN)

BACKGROUND

By one estimate, 60% of women experiencing the menopause transition perceive that they have memory problems, but most studies that have used cognitive function tests have not substantiated a relation between menopause stage and cognitive performance. We sought to describe the cross-sectional relation between menopause status, estradiol (E(2)), follicle-stimulating hormone (FSH), and measured cognitive function.

METHODS

Cross sectional analysis of a community-based cohort of midlife women was used. Cognitive tests were the East Boston Memory Test, Symbol Digit Modalities, and Digits Span Backward. Menopause categories (premenopausal, early perimenopausal, late perimenopausal, and postmenopausal) were defined based on menstrual patterns. One set of general linear models assessed the relations between each cognitive test and menopause transition category, initially adjusted for age, race/ethnicity, education, symptoms, self-rated general health, and body mass index (BMI); next, these were additionally adjusted for FSH and E(2). A second set of models, stratified by menopause status, examined the possible relations between each cognitive test and either E(2) or FSH, adjusted for age, race/ethnicity, education, symptoms, self-related general health, and BMI.

RESULTS

The mean age of the analytical sample (n = 1657) was 49.7 years. Only 5% of the sample had less than a high school education, 16% graduated from high school, and the rest had at least some college. The percent of women in each menopause category was premenopausal (9.0%), early perimenopausal (57.0%), late perimenopausal (13.4%), postmenopausal (20.6%). Although clinical-site adjusted models showed moderate differences between menopause transition groups and cognitive performance, no association was found between each of the measured cognitive performance tests and menopause transition status when adjusting for covariates. Similarly, no association between each cognitive test and E(2) or FSH was found.

CONCLUSIONS

This study does not support a cross-sectional relation between cognitive test performance and menopause stage, FSH, or E(2).

Working-Delayed Memory Difference Detects Mild Cognitive Impairment Without Being Affected by Age and Education

Performance on neuropsychological tests is affected by age and education, which makes the early detection of cognitive impairment difficult when assessing individuals of varying levels of education. We examined the effects of age, education, and gender on three memory indexes of the Wechsler Memory Scale-III, Delayed Memory, Working Memory and the difference between Working-Delayed Memory in a sample of patients with amnestic Mild Cognitive Impairment, patients with mild probable Alzheimer's disease, and a nondemented elderly comparison group. Whereas Delayed and Working Memory scores were affected by participant type, age, and education, the Working-Delayed Memory difference score was affected by participant type, only. Our preliminary conclusions, pending replication of the findings with a larger sample, are that working-delayed memory difference was sensitive to early memory decline without being affected by age and education.

Musculoskeletal pain complaints and performance on cognitive tasks over the adult life span

The present study aimed at comparing participants with and without self reported musculoskeletal pain in a normal population with regard to performance on a range of tests for episodic memory, semantic memory, and other cognitive functions and to see if expected differences interacted with age. The results showed that participants with pain performed worse on a range of tasks as compared to participants without pain, and that these differences occurred regardless of age. The most robust effects of pain were displayed on tests for vocabulary and construction ability as these were the only effects that remained significant after controlling for years of education and reported depression in separate analyses. When depression and education were controlled for in the same analysis, even these effects were eliminated, suggesting interplay between pain, depressive status, and educational level in the negative effects on cognitive functioning.

Activation of early components of complement targets myelin and oligodendrocytes in the aged rhesus monkey brain

The disruption and loss of myelin in the white matter are some of the major changes that occur in the brain with age. In vitro studies suggest a role of the complement system in the catabolic breakdown of myelin membranes. This study presents findings on activation of the early components of complement cascade in the brains of both young and aged rhesus monkeys with evidence of increased complement activation in aged animals. Complement containing oligodendrocytes (CAOs) containing C3d and C4d complement activation products bound to oligodendrocytes and myelinated fibers were found in the brain of normal young and old animals. The CAOs, which also contained activated microglia, were distributed throughout the whole brain and in significantly greater numbers in the aged monkeys. These findings, together with the demonstration of covalent binding of the C3 fragments to myelin, suggest the initiation of the complement cascade by myelin and oligodendrocytes, which are known classical complement activators. Activation of terminal complement components was not demonstrable in the CAOs. Taken together the findings support the concept that activation of early components of complement in the brain may be a normal biological process that involves the metabolism of myelin and oligodendrocytes and up-regulates with age.

Increase in epinephrine excretion is associated with cognitive decline in elderly men: MacArthur studies of successful aging

BACKGROUND

High stress hormone levels are associated with increased risk of cognitive decline in elderly individuals. However, the effect of late-life changes in stress hormone levels on cognitive decline risk has not been examined. Our objective was to investigate whether increase over time in urinary epinephrine excretion in older adults was associated with subsequent cognitive decline.

METHODS

Measurements were made on 154 high-functioning men and women, 70-79 years of age, in 1988, 1991, and 1995. Twelve-hour overnight urinary excretion of epinephrine (normalized by creatinine excretion to adjust for body size) was recorded in 1988 and 1991. Cognitive functioning was assessed in 1991 and 1995 by summary scores based on standard tests of language, memory, abstraction, spatial recognition, and spatial construction.

RESULTS

Compared to individuals whose epinephrine excretion decreased between 1988 and 1991, the individuals whose epinephrine excretion increased over the same period had greater subsequent declines in summary cognitive scores between 1991 and 1995. After adjusting for baseline epinephrine, baseline cognitive function, and relevant covariates, and stratifying by gender, increases in urine epinephrine were positively associated with cognitive decline only in men.

CONCLUSIONS

We conclude that increase in urinary excretion of epinephrine predicts subsequent cognitive decline in older men.

Participating in social activities helps preserve cognitive function: an analysis of a longitudinal, population-based study of the elderly

BACKGROUND

This study examines how changes in cognition over time are related to participation in social activities and the extent of social networks.

METHODS

Data are drawn from a population-based, longitudinal study that began in 1989 among elderly Taiwanese. An over-dispersed Poisson model is used to regress the number of failed cognitive tasks (0-5) in 1996, 1999, and 2000 on prior measures of cognitive impairment, social activities, social networks, health status, and sociodemographic characteristics. The analysis sample comprises 2387 individuals, who contribute a total of 4603 observations across three survey intervals (1993-96, 1996-99, 1999-2000).

RESULTS

After adjusting for prior cognitive impairment, baseline health status, and sociodemographic factors, respondents who participated in one or two social activities failed 13% fewer cognitive tasks (P < 0.01) than those with no social activities; those who engaged in three or more activities failed 33% fewer cognitive tasks (P < 0.001). In contrast, none of the social network measures was related to cognitive impairment.

CONCLUSIONS

Despite a social structure where elderly persons often live with their children and social interaction is likely to be more family-centered than in western countries, data from Taiwan suggest that participation in social activities outside the family may have a bigger impact on cognitive function than social contacts with family or non-relatives.

Homocysteine versus the vitamins folate, B6, and B12 as predictors of cognitive function and decline in older high-functioning adults: MacArthur Studies of Successful Aging

BACKGROUND

Elevated plasma total homocysteine concentration may be a risk factor for cognitive decline and Alzheimer disease, but data from prospective studies are limited. Further, high homocysteine levels are associated with low vitamin status, and it is unknown whether it is homocysteine toxicity or vitamin insufficiency that is responsible for the observed cognitive dysfunction.

METHODS

We performed cross-sectional and longitudinal analyses of a cohort of 499 high-functioning community-dwelling persons aged 70 to 79 years to determine the effect of homocysteine and related vitamin plasma concentrations on cognitive function and cognitive decline. Nonfasting plasma concentrations of homocysteine, folate, vitamin B(6), and vitamin B(12) were measured at baseline. Summary measures of cognitive function were created from tests of multiple cognitive domains administered at baseline and again after 7 years.

RESULTS

In cross-sectional analyses investigating each variable separately, subjects with elevated homocysteine levels, or low levels of folate or vitamin B(6), demonstrated worse baseline cognitive function. In longitudinal analyses, after adjusting for multiple covariates, including homocysteine, those in the bottom quartile of folate had a 1.6-fold increased risk (95% confidence interval: 1.01 to 2.31; P =0.04) of being in the worst quartile of 7-year cognitive decline. Low folate levels largely accounted for a trend towards greater cognitive decline with elevated homocysteine level.

CONCLUSION

In high-functioning older adults, low folate levels appear to be a risk factor for cognitive decline. The risk of developing cognitive decline might be reduced through dietary folate intake.

Cognitive Decline in High-Functioning Older Persons Is Associated with an Increased Risk of Hospitalization

OBJECTIVES

To examine hospital use for patients with evidence of cognitive decline indicative of early cognitive impairment.

DESIGN

Medicare Part A hospital utilization data were linked to data from the MacArthur Research Network on Successful Aging Community Study to examine the association between baseline cognition and decline in cognitive function over a 3-year period and any hospitalization over that same period.

SETTING

New Haven, Connecticut, and East Boston, Massachusetts.

PARTICIPANTS

Subjects (N=598) were from two sites of the MacArthur Research Network on Successful Aging Community Study, a 7-year cohort study of community-dwelling older persons with high physical and cognitive functioning.

MEASUREMENTS

Multivariate logistic regression was used to determine the association between any hospitalization over 3 years (1988-91) as the outcome variable and baseline cognitive function and decline in cognition over 3 years as primary predictor variables. Decline was based upon repeated (1988 and 1991) measures of delayed verbal recall and the Short Portable Mental Status Questionnaire (SPMSQ).

RESULTS

Of 598 subjects, 48 died between 1988 and 1991. No baseline (1988) delayed recall scores or change in recall scores (1988-91) were associated with hospitalization. Although 48.2% declined on verbal memory scores, decline was not associated with risk of hospitalization. Of 494 subjects with complete 3-year data, 31.2% declined at least one point on the SPMSQ, and 4.7% declined more than two points. Among individuals aged 75 and older at baseline, the adjusted odds ratio for hospitalization for those who declined more than 2 points compared with those who declined less was 7.8 (95% confidence interval=2.0-30.8).

CONCLUSION

Although specific memory tests were not associated with hospitalization, high-functioning older persons who experienced decline in overall cognitive function were more likely to be hospitalized. Variation in baseline cognitive function in this high-functioning cohort did not affect hospitalization, but additional research is needed to evaluate associations with other healthcare costs.

Activation of calpain-1 in myelin and microglia in the white matter of the aged rhesus monkey

Ultrastructural disruption of myelin sheaths and a loss of myelin with age are well-documented phenomena in both the human and rhesus monkey. Age-dependent activation of calpain-1 (EC 3.4.22.52) has been suggested as a plausible mechanism for increased proteolysis in the white matter of the rhesus monkey. The present study documents activation of calpain-1 throughout brain white matter in aged animals, evidenced by immunodetection of the activated enzyme as well as a calpain-derived spectrin fragment in both tissue section and Triton X-100-soluble homogenate of subcortical white matter from the frontal, temporal, and parietal lobes. Separation of myelin fractions from brain stem tissue into intact and floating myelin confirmed previous reports of an age-related increase in activated calpain-1 in the floating fraction. Measurements of calpain-1 activity using a fluorescent substrate revealed an age-related increase in calpain-1 proteolytic activity in the floating myelin fraction consistent with immunodetection of the activated enzyme in this fraction. Double-immunofluorescence demonstrated co-localization of activated calpain-1 with human leukocyte antigen-DR (HLA-DR), a marker for activated microglia, suggesting that these cells represent the major source of the increase in activated calpain-1 in the aging brain. These data solidify the role of calpain-1 in myelin protein metabolism and further implicate activated microglia in the pathology of the aging brain.

The fate of cognition in very old age: six-year longitudinal findings in the Berlin Aging Study (BASE)

The authors report full-information longitudinal age gradients in 4 intellectual abilities on the basis of 6-year longitudinal changes in 132 individuals (mean age at T1 = 78.27, age range = 70-100) from the Berlin Aging Study. Relative to the cross-sectional parent sample (N = 516, mean age at T1 = 84.92 years), this sample was positively selected because of differential mortality and experimental attrition. Perceptual speed, memory, and fluency declined with age. In contrast, knowledge remained stable up to age 90, with evidence for decline thereafter. Age gradients were more negative in old old (n = 66, mean age at T1 = 83.04) than in old (n = 66, mean age at T1 = 73.77) participants. Rates of decline did not differ reliably between men and women or between participants with high versus low life-history status. They conclude that intellectual development after age 70 varies by distance to death, age, and intellectual ability domain.

Age-dependent myelin degeneration and proteolysis of oligodendrocyte proteins is associated with the activation of calpain-1 in the rhesus monkey

Myelin provides important insulating properties to axons allowing for propagation of action potentials over large distances at high velocity. Disruption of the myelin sheath could therefore contribute to cognitive impairment, such as that observed during the normal aging process. In the present study, age-related changes in myelin, myelin proteins and oligodendrocyte proteins were assessed in relationship to calpain-1 expression and cognition in the rhesus monkey. Isolation of myelin fractions from brain white matter revealed that as the content of the intact myelin fraction decreased with age, there was a corresponding increase in the floating or degraded myelin fraction, suggesting an increased breakdown of intact myelin with age. Of the myelin proteins examined, only the myelin-associated glycoprotein decreased with age. Levels of the oligodendrocyte-specific proteins 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and myelin/oligodendrocyte-specific protein (MOSP) increased dramatically in white matter homogenates and myelin with age. Age-related increases in degraded CNPase also were demonstrable in white matter in association with increases in activated calpain-1. Degraded CNPase was also detectable in myelin fractions, with only the floating fraction containing activated calpain-1. The increases in the activated enzyme in white matter were much greater than those found in myelin fractions suggesting a source other than the myelin membrane for the marked overexpression of activated calpain-1 with age. In addition, CNPase was demonstrated to be a substrate for calpain in vitro. In summary, changes in myelin and oligodendrocyte proteins occur with age, and they appear to have a significant relationship to cognitive impairment. The overexpression of CNPase and MOSP suggests new formation of myelin by oligodendrocytes, which may occur in response to myelin degradation and injury caused by proteolytic enzymes such as calpain.

Predicting cognitive impairment in high-functioning community-dwelling older persons: MacArthur Studies of Successful Aging

OBJECTIVES

To examine whether simple cognitive tests, when applied to cognitively intact older persons, are useful predictors of cognitive impairment 7 years later.

DESIGN

Cohort study.

SETTING

Durham, North Carolina; East Boston, Massachusetts; and New Haven, Connecticut, areas that are part of the National Institute on Aging Established Populations for Epidemiological Studies of the Elderly.

PARTICIPANTS

Participants, aged 70 to 79, from three community-based studies, who were in the top third of this age group, based on physical and cognitive functional status.

MEASUREMENTS

New onset of cognitive impairment as defined by a score of less than 7 on the Short Portable Mental Status Questionnaire (SPMSQ) in 1995.

RESULTS

At 7 years, 21.8% (149 of 684 subjects) scored lower than 7 on the SPMSQ. Using multivariate logistic regression, three baseline (1988) cognitive tests predicted impairment in 1995. These included two simple tests of delayed recall-the ability to remember up to six items from a short story and up to 18 words from recall of Boston Naming Test items. For each story item missed, the adjusted odds ratio (AOR) for cognitive impairment was 1.44 (95% confidence interval (CI) = 1.16-1.78, P <.001). For each missed item from the word list, the AOR was 1.20 (95% CI = 1.09-1.31, P <.001). The Delayed Recognition Span, which assesses nonverbal memory, also predicted cognitive impairment, albeit less strongly (odds ratio = 1.06 per each missed answer, 95% CI = 1.003-1.13, P =.04).

CONCLUSIONS

This study identifies measures of delayed recall and recognition as significant early predictors of subsequent cognitive decline in high-functioning older persons. Future efforts to identify those at greatest risk of cognitive impairment may benefit by including these measures.

Peripheral blood markers of inflammation predict mortality and functional decline in high-functioning community-dwelling older persons

OBJECTIVES

Several peripheral blood markers of inflammation have demonstrated prognostic ability, but the value of combining multiple markers as a measure of inflammatory burden remains unknown. The objective of this study was to determine the prognostic value of combining four peripheral blood measures of inflammation in healthy older persons.

DESIGN

Inception cohort study with 7 years of follow-up.

SETTING

Three communities.

PARTICIPANTS

Eight hundred seventy high-functioning subjects aged 70 to 79 who had serum albumin, cholesterol, interleukin (IL)-6, and C-reactive protein (CRP) levels measured at baseline.

MEASUREMENTS

Three- and 7-year mortality and Rosow- Breslau functional decline.

RESULTS

A summary score was created that assigned one point each for the following blood levels: albumin <3.8 g/dL, cholesterol <170 mg/dL (bottom decile), IL-6>3.8 pg/mL (top tertile), and CRP>2.65 mg/L (top tertile). By 3 years, 6% of subjects had died, and, by 7 years, 23% had died. In subjects with three or four markers of inflammation, the adjusted odds ratios (AORs) for 3- and 7-year mortality were 6.6 and 3.2, respectively, compared with those who had no abnormal markers. Subjects with one or two markers were at more moderate and statistically insignificant increased risk of 3- and 7-year mortality with AORs of 1.5 and 1.3, respectively. The risks for functional decline at 3- and 7-years were generally small (AOR = 1.1-1.9) and not statistically significant.

CONCLUSIONS

In high-functioning older persons, a measure of inflammation can identify those at a much higher risk of mortality and a possibly higher risk of functional decline. Whether therapies directed at reducing inflammation can attenuate such risk remains to be determined.

Ethnicity and cognitive performance among older African Americans, Japanese Americans, and Caucasians: the role of education

This cross-sectional analysis evaluated the association between ethnicity and cognitive performance and determined whether education modifies this association for nondemented older people (103 African Americans, 1,388 Japanese Americans, 2,306 Caucasians) in a study of dementia incidence. African Americans scored lower (median 89 out of 100) than Japanese Americans (93) and Caucasians (94) on the Cognitive Abilities Screening Instrument (CASI). Education affected CA

Fluctuations in spatial recognition memory across the menstrual cycle in female rhesus monkeys

Findings are inconsistent regarding whether women's cognitive performance fluctuates across phases of the menstrual cycle, but differences in methodology and the use of reported cycle phase rather than precise hormonal measures may underlie these disparities. Studies in monkeys may help resolve these discrepant findings, since hormonal status can be reliably determined. We tested four young (5-7 years old) female rhesus monkeys daily during one entire menstrual cycle on three cognitive tasks displayed on a computerized touch-screen system: a Matching to Sample task with a 30 s delay (MTS-30s), a Matching to Sample task without delay (MTS-no delay) and the spatial condition of the Delayed Recognition Span Test (spatial-DRST). Blood samples were collected at specific time intervals throughout the cycle and assayed for estradiol and progesterone in order to identify hormonal status. There was a nonsignificant trend for the MTS-30s scores to be better during the follicular and luteal phases, when estradiol levels were low, than during the peri-ovulatory phase, when estradiol levels were at their highest. MTS-no delay performance did not vary as a function of hormonal status. Spatial-DRST scores were significantly better during the follicular and luteal phases than during the peri-ovulatory phase of the cycle. These data in the female rhesus monkey support the hypothesis that spatial memory performance is sensitive to estradiol variations across the menstrual cycle, with better performance associated with low estradiol levels.