Neuropsychological characteristics of normal aging

Abstract

A basic neuropsychological battery was given to 346 normal adults. Participant characteristics were balanced according to: (a) age (55 to 60, 61 to 65, 66 to 70, 71 to 75, 76 or older), (b) sex, and (c) educational level (0 to 5 years, 6 to 12 years, more than 12 years of schooling). The items of the neuropsychological battery assessed language, memory, attention, abstraction, and constructional abilities, and also included a behavioral scale. Differences based on educational level were found for 28 of the 29 tests used, and age differences were found for 23, with better performance among younger and more highly educated participants. Sex differences were found for 10 tests, with better performance among males in 9 of these tasks. Few interactions were significant. A factor analysis was performed in which 43 factors were found to explain the total variance. However, a single factor explained 35.9% of the variance; this factor was related to visuospatial and visuomotor abilities. A second factor (6% of the variance) was related to verbal learning. A third factor (4.6% of the variance) was clearly related to speed, and a fourth factor (3.9% of the variance) to verbal semantic memory. Implications of these results are discussed.