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The effects of advanced age and cognitive resources on the course of skill acquisition are unclear, and discrepancies among studies may reflect limitations of data analytic approaches. We applied a multilevel negative exponential model to skill acquisition data from 80 trials (four 20-trial blocks) of a pursuit rotor task administered to healthy adults (19-80 years old). The analyses conducted at the single-trial level indicated that the negative exponential function described performance well. Learning parameters correlated with measures of task-relevant cognitive resources on all blocks except the last and with age on all blocks after the second. Thus, age differences in motor skill acquisition may evolve in 2 phases: In the first, age differences are collinear with individual differences in task-relevant cognitive resources; in the second, age differences orthogonal to these resources emerge. Key Words: Aging--Motor performance--Multilevel model Negative exponential learning function--Pursuit rotor--Skill acquisition--Working memory. doi: 10.1093/geronb/gbp126

We examined whether higher levels of neuroticism in adolescence were associated with poorer cognitive function in midlife in 2,071 members of the British 1946 birth cohort. Higher neuroticism at age 13 was associated with poorer performance on tests of verbal ability, verbal fluency, and verbal memory at age 53 in sex-adjusted analyses. However, higher neuroticism was also associated with poorer cognitive performance at age 8. After adjustment for childhood cognition or educational attainment, the associations between neuroticism at age 13 and midlife cognition ceased to be statistically significant. The link between neuroticism and subsequent cognitive ability may be a reflection of a long-standing correlation between the stable aspects of these traits since childhood, but further measurements of both traits are needed to confirm this. Key Words: Personality--Neuroticism--Cognition--Life course and developmental change. doi: 10.1093/geronb/gbp082.

Background. Among persons with white matter lesions (WMLs), there is a range of cognitive function. We examine whether participation in leisure activities modifies the effect of WML load on cognitive function. Methods. Data are from 2300 men and women (aged 66-92 years) participating in the population-based Age Gene/ Environment Susceptibility-Reykjavik Study. Subcortical WML load was calculated as a weighted sum, based on size of lesions in the four lobes. Periventricular WML load was calculated as the sum of lesion scores, based on size, for the frontal caps, occipitoparietal caps and bands. The upper quartile of lesion load in either area was compared to the lower three quartiles. Composite scores of memory (MEM), speed of processing (SP), and executive function (EF) were constructed from a battery of neuropsychological tests. Frequency of participation in nine cognitively stimulating leisure activities was assessed via questionnaire; the upper quartile was compared to the lower three quartiles. Multiple regression, controlling for demographic and health factors and brain infarcts, was used to test the main effects and interaction of WMLs and leisure activity on cognitive function. Results. High leisure activity was associated with higher performance in all three cognitive abilities: MEM [beta] = 0.20, 95% confidence interval [CI], 0.11-0.29; SP [beta] = 0.37, 95% CI, 0.29-0.45; and EF [beta] = 0.23, 95% CI, 0.15-0.29. High WML load was associated with significantly lower performance in SP ([beta] = -0.06, 95% CI, -0.13 to -0.01). The effect of WMLs on SP performance was modified by high leisure activity (p for interaction < .05). Conclusion. Participation in cognitively stimulating leisure activity may attenuate the effect of WML pathology on cognitive performance. Key Words: Epidemiology--Cognition--White matter lesions--Leisure activity.

During a 20-year longitudinal study, 5,842 participants aged 49 to 93 years significantly improved over two to four successive experiences of the Heim AH4-1 intelligence test (first published in 1970), even with between-test intervals of 4 years and longer. After we considered significant attrition by death and dropout and the effects of gender, socioeconomic advantage, and recruitment cohort, we found that participants with high intelligence test scores showed greater improvement than did those with lower intelligence test scores. Practice gains also reduced with age, even after we took into consideration the individual differences in intelligence test scores. This emphasizes the methodological point that neglect of individual differences in improvement during longitudinal studies underestimates age-related changes in younger and more able participants and the theoretical point that, like all experiences during everyday life, participation in longitudinal studies alters the ability of aging humans to cope with cognitive demands to different extents according to their baseline abilities. Key Words: Cognitive gain--Longitudinal study--Practice gains.

Background. Although several studies have investigated the association between cholesterol and dementia, few have examined cholesterol and decline across cognitive domains. We examined serum total and high-density lipoprotein (HDL) cholesterol, total-to-HDL ratio, and trajectories across cognitive domains. Methods. Participants were 436 community-residing women (70-79 years old) in the Women's Health and Aging Study II; they were screened to be physically high-functioning and cognitively intact at baseline. Cognition and other health-related variables were assessed at five intervals spanning 9 years. Cognitive assessments included Trail Making Test Parts A (TMT-A) and B (TMT-B), Hopkins Verbal Learning Test-Revised, Purdue Pegboard, and Mini-Mental State Examination (MMSE). The association between baseline levels of serum lipids and cognitive trajectories were evaluated using Generalized Estimating Equations (GEE). Covariates included age, education, race, vascular disease, serum creatinine, depression, and lipid-lowering medications. Results. In multivariate analyses, baseline higher total (p = .02) and HDL (p = .03) cholesterol were associated with better performance on the Purdue Pegboard. Using clinical cholesterol cutoffs, baseline serum total cholesterol levels > 240 mg/dL were associated with the best performance (p = .02). Baseline lipids were not associated with any other cognitive tests; there were no Lipid x Time interactions. Conclusion. Higher baseline serum lipid levels predicted better performance over time on a measure of motor speed, but not memory or psychomotor or executive functioning in this population of elderly women. This association suggests that peripheral cholesterol levels, measured in late-life, may not be a good predictor of subsequent cognitive decline. Future research examining peripheral cholesterol over the life span and its relationship with cognition is needed. Key Words: Cholesterol--Cognition--Motor speed--Biological aging.

Background. This study examines interrelationships among age, hormones, and cognition for middle-aged and elderly men, and tests whether hormones predict lower cognitive functioning and mediate the age cognition relationship. Methods. We analyzed Time 2 data from the Massachusetts Male Aging Study, a population based cohort study. Selection criteria included complete reformation on cognition and hormones (n = 981). Cognitive measures included working memory (Backward Digit Span test), speed/attention (Digit Symbol Substitution test), and spatial ability (Figural Relations test). Hormones included free testosterone, total testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstanediol glucuronide (3 [alpha]-A-diol glue), luteinizing hormone (LH), follicle-stimulating hormone (FSH), sex hormone-binding globulin (alternatively known as a 'binding protein') (SHBG), prolactin (PRL), estrone ([E.sub.1]), and cortisol (CRT). Age was measured in years. Adjusted analyses added educational attainment, health conditions and behaviors, body mass index, and depression. Results. Older age was associated with lower cognitive functioning. In unadjusted models, logged free and total testosterone, DHEA, and DHEAS related to higher functioning in at least one cognitive domain; logged FSH, SHBG, and LH related to lower functioning in at least one cognitive domain; and logged [E.sub.1], CRT, and PRL were not significant. In adjusted models, logged hormones did not relate to cognitive function except for logged [E.sub.1] and CRT, which had negative effects. Logged hormones did not mediate the age-cognition relationship. Conclusions. The direct effects of hormones on cognition are not significant when salient factors are considered. Further, hormones do not mediate the age cognition relationship; it is necessary to look to other explanatory pathways.

Research shows that there is a general decline in cognitive performance during aging especially in those who are older or near death and prone for dementia. Furthermore, the fact that elimination of the latter group does not change the picture much suggests that the aging process uniformally exerts negative functioning.

Background. Previous literature indicates that attentional resources are required for recovery of postural stability. Previous studies have also examined the effect of aging on the performance of a static postural task while a secondary cognitive task is being conducted. This study describes the effect of a cognitive task on the neuromuscular response characteristics underlying reactive balance control in young versus older adults. Methods. The attentional demand on the neuromuscular system was examined in 14 young and 12 healthy older adults by analysis of the integrated electromyography activity while the adults were performing a dual-task paradigm. The primary task involved standing platform perturbations and the secondary task was a math task that involved subtraction by threes. Integrated electromyography activity was compared between the cognitive (math and balance) task versus control (balance only) task. Results. For both groups of subjects, onset latency of postural muscle responses did not change under dual-task conditions. In contrast, the amplitude of postural muscle activity was significantly affected by performance of a secondary task. When electromyography data were combined for both young and older adults, there was a decrease in muscle response amplitude in both agonist (gastrocnemius) and antagonist (tibialis anterior) muscles when the cognitive math task was performed. This was apparent at 350-500 milliseconds from plate onset for the gastrocnemius and between 150 and 500 for the tibialis anterior. When young and older adults were compared, an age by task interaction effect was seen in muscle response amplitude for the agonist (gastrocnemius) muscle between 350 to 500 milliseconds, with older adults showing a significantly greater reduction than young adults. Conclusion. The decline of muscle activity when the secondary task was performed suggests that less attentional processing capacity was available for balance control during the dual-task paradigm. The results also indicate that the dual-task activity has a greater impact on balance control in the older adults than in the young adults.

Apolipoprotein E (epsilon)4 may not affect cognitive performance in adults without dementia. When it does influence cognitive performance, such may be related to impending dementia rather than to the effect of the genotype on cognition in normal aging. This was gleaned from a study of whether baseline cognitive performance and three-year longitudinal changes were influenced by apolipoprotein E (epsilon)4 status. Of specific focus were cognitive abilities that include memory, visuospatial functioning and verbal fluency.

We report an investigation of postural stability in two groups of volunteers (mean ages of 57 and 77). Participants were required to stand on a force platform while performing five cognitive tasks: (1) random digit generation, (2) Brooks' spatial memory, (3) backward digit recall, (41 silently counting from 1-700, and (5) counting backward in threes (aloud). =There was also a control condition in which there was no cognitive task. Postural stability was adversely affected by age in all conditions. Moreover, the difference between the two age groups was significantly greater when performing tasks 2 and 3, in comparison with the age difference in the control condition. Regression analyses revealed that the effect of age on postural stability while performing these particular tasks remained significant even after the following measures were included in the regression: postural stability in the control condition, cognitive performance, intelligence, and speed. We suggest that age differences in postural stability are increased by cognitive tasks requiring use of the visuo-spatial sketchpad component of working memory.

The influence of cardiovascular signs (CVS) on cognitive performance was examined in 227 older adults not suffering from dementia between 75 and 96 years of age who were sampled from the community. Participants received a comprehensive physical examination that included specific evaluation of current CVS, including dyspnea, cardiac murmur, and edema in lower limbs. They were administered tests of digit span, episodic recall and recognition, verbal fluency, and visuospatial skill. CVS were found to predict performance on tests of episodic memory and visuospatial skill, after the effects of age, education, gender, relevant drug use, and mood symptoms were controlled for. Although CVS accounted for relatively little general performance variation, the findings are relevant to the understanding of normal variation in late-life cognitive performance. Finally, CVS increased with age and accounted for a sizable proportion of the age-related cognitive variation.