Topography of auditory and visual P300 in normal children.

Auditory and visual P300 recordings were performed on 39 normal, right-handed individuals from age 6 through 15, using 31 evenly spaced scalp electrodes. Amplitude at the P300 peak and latency to this peak at each electrode site were measured. Age was significantly correlated with the 31-electrode mean for auditory and visual P300 latencies, but not for amplitudes. The younger age group (6-10) had longer auditory and visual P300 latencies than the older age group. Visual P300 amplitudes were of an overall larger magnitude than auditory amplitudes. There were no other differences including significant topographical differences in P300 amplitudes or latencies by gender, age group, modality, or side of scalp. Radial current density maps on group-averaged auditory and visual P300 waveforms at the group mean P300 latency at Cz, showed a right centroparietal sink surrounded by sources. This suggests a major right centroparietal P300 generator. Description of the normal topography of the P300, and demonstration of the lack of topographic differences by gender, age group, modality, or side of scalp, may facilitate the meaningful examination of P300 topography in cognitive disorders. Such an examination might lead to better diagnostic tools and more appropriate treatment of cognitive disorders in children.