A STUDY OF PERFORMANCE ON TESTS FROM THE CANTAB BATTERY SENSITIVE TO FRONTAL-LOBE DYSFUNCTION IN A LARGE-SAMPLE OF NORMAL VOLUNTEERS - IMPLICATIONS FOR THEORIES OF EXECUTIVE FUNCTIONING AND COGNITIVE AGING

Several tests from the CANTAB neuropsychological test battery previous ly shown to be sensitive to frontal lobe dysfunction were administered to a large group of normal volunteers (N = 341) ranging in age from 2 1 to 79 years. The main tests included a computerized form of the Towe r of London test of planning, a self-ordered spatial working memory ta sk, and a test of attentional set formation and shifting. A computeriz ed form of the Corsi spatial span task was also given. Age-related gra ded declines in performance were seen, sometimes in a discontinuous ma nner, especially for the attentional set shifting task (at the extradi mensional shift stage). Patterns of deficits reminiscent of frontal lo be or basal ganglia damage were observed in the oldest age group (74-7 9). However, overall the data were only partially consistent with the hypothesis that frontal lobe functions are the most sensitive to effec ts of aging. Factor analyses showed that performance in the executive tests was not simply related to a measure of fluid intelligence, and t heir performance had a factor loading structure distinct from that for the CANTAB tests of visual memory and learning previously administere d to the same sample. Finally, only limited support was found for the hypothesis that cognitive aging depends on slowed information processi ng.