Reproducibility of P3

The P3 event-related potential has been widely employed in both clinical and research investigations. In the present study, P3 latency and amplitude intersession reliability were evaluated in 4 sessions over an average of 33 days in 24 healthy adults using the P3 tonal oddball paradigm. Mean group latencies ranged from 302-305 ms and mean amplitudes ranged from 7.75-8.87 μV. No significant group differences were found across sessions for latency or amplitude. Intrasubject variability was large; the 95% confidence interval for the difference between the means of two combined sessions was ±20 ms for latency and ±4.63 μV for amplitude. The results suggest that P3 latency and amplitude are reliable and reproducible over weeks for groups, but have greater variability for individuals.