Age-related dynamics of cognitive brain functions in humans: an electrophysiological approach

Event-related P300 potentials closely reflect cognitive functions such as stimulus discrimination (N250) and processing time (P300 latencies) as well as attention capabilities (P300 amplitudes). To delineate the age-related dynamics of P300 potentials, we investigated 250 healthy subjects between 18 and 98 years of age in a cross-sectional study. A total of 330 visual P300 tests was performed in two different paradigms (PI, passive condition, n = 80; PII, active condition, n = 250). In both P300 paradigms, the N250 and P300 latencies were markedly prolonged (p < .0001) in older age, whereas the N250 and P300 latency differences between PII and PI did not change (p > .05). The P300 amplitudes in paradigm I and II revealed only a slight age-related reduction. In fact, the P300 amplitude ratios between PII and PI remained constant. Third-order polynomial regressions provided the best fit of the aging-P300 interactions in paradigms I and II for both males and females. Interestingly, females showed a greater and possibly earlier P300 latency increase during aging than males. These age-related changes of P300 potentials indicate a rather mild cognitive decline that does not accelerate before old age and may be different between both sexes.