INDIVIDUAL-DIFFERENCES IN P3 SCALP DISTRIBUTION IN OLDER ADULTS, AND THEIR RELATIONSHIP TO FRONTAL-LOBE FUNCTION

There is evidence that frontal lobe function may diminish in normal ag ing. The P3 component of the event-related brain potential (ERP) elici ted by target events in an oddball paradigm becomes more frontally ori ented in elderly subjects. It was hypothesized that the extent to whic h the P3 distribution is frontally oriented in old subjects may index less efficient frontal lobe function. In this study, bootstrapping met hods were used to establish the reliability of the locations of maxima of surface brain activity obtained with ERP recordings from young and old subjects. The results indicated that brain activity maxima are re liable for a given individual. However, among the elderly only, there were also clear individual differences in the distribution of the P3 c omponent elicited by target stimuli in an oddball paradigm. On the bas is of these differences, the old subjects were divided into two groups . In line with predictions, those elderly subjects who showed frontal- maximal P3 scalp distributions had lower performance on standardized n europsychological tests of frontal lobe function than those elderly su bjects who showed posterior-maximal scalp topographies.