Exponential electrophysiological aging: P3 latency.

Forty-nine normal volunteer subjects ranging in age from 15 to 80 years were studied in an 'auditory oddball' event-related potential paradigm. In certain respects our results replicate other studies, finding significant correlations between age and both N2 and P3 latency. Slopes of the linear age/ERP latency regression function increased with component number (i.e., N1 less than P2 less than N2 less than P3). Further analysis disclosed that the age/ERP component latency relationship is non-linear. Separate age/ERP component latency linear regression functions were computed for subjects 15-45 and 46-80. None of these functions were significant for subjects under 45. Age/latency slopes were significant in the older group for P2, N2 and P3. The age/P3 latency slope for the subjects under 45 was 0.53 msec/year, versus 3.14 msec/year for the subjects over 45. The data for P3 latency and age are best fitted with a curvilinear first and second degree orthogonal polynomial, which describes a positively accelerating latency increase with age. Clinical implications of the form of the age/P3 latency regression function (curvilinear vs. linear) are discussed.