Reliability of late positive component activity (P3) in healthy elderly adults.

Auditory oddball paradigms (20% targets) were used to elicit components of the event-related brain potential in healthy, late middle-aged and elderly adults (N = 32) in two separate sessions approximately 4.5 months apart. Within each session data were acquired under two conditions: (a) 250 Hz standard, 500 Hz target; and, (b) 1000 Hz standard, 2000 Hz target. Measures of P3 latency and amplitude showed moderate to high reliability (.55 to .89) over the 4.5-month interval under both stimulus conditions using data acquired from the midline frontal (Fz), central (Cz), and parietal (Pz) sites. In the second session, latencies were prolonged in the 500 Hz target tone condition, and amplitudes tended to be reduced in the 2000 Hz target tone condition. These results suggest that P3 measures in studies of older adults are reliable over time, and the findings are discussed in conjunction with prior P3 reliability studies of younger adults.