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

BACKGROUND
The purpose of this study was to examine the role of demographic factors as predictors of cognitive performance in a high-functioning, community-dwelling elderly population.


METHODS
The study cohort consisted of 1,192 community-dwelling subjects, who were selected to represent the highest third of an elderly population with respect to physical and cognitive functioning. A neuropsychological battery, including 5 cognitive performance subtests (confrontation naming, delayed recognition span, similarities, figure-copying, and incidental delayed recall) was administered to the subjects in their homes.


RESULTS
A summary measure of the 5 neuropsychological subtest scores, the total cognitive score, arrayed the study group across a broad range of difficulty, creating a near-normal distribution. Education, income, and race had statistically significant associations with the total score and the individual subtests. The effect of education was the most striking finding, explaining 30% of the variance in the total score. Education was most strongly related to the abstraction (partial R2 = .11) subtest, and least related to the memory subtests, delayed recognition (R2 = .02) and delayed recall (R2 = .01).


CONCLUSIONS
Demographic factors are important predictors of cognitive performance in this high-functioning cohort. Education had the strongest influence on overall cognitive performance, and particularly notable associations with subtests that depended upon the use of previously learned materials. Longitudinal follow-up, now underway, will help to determine whether high levels of education help to maintain cognitive performance with age.