Developmental change of short latency somatosensory evoked potential waves between P3 and N1 components in children

We attempted to isolate and identify the negative waves between the conventional P 3 and N 1 components of short latency somatosensory evoked potentials (S-SEPs) in children. Twenty normal children ranging in age from 3 months to 12 years, and 11 adolescents and adults were studied. The median nerve was stimulated and recordings from F (F 3 or F 4 ) and C (1–2 cm posterior to C 3 or C 4 ) contralateral to the stimulation site were simultaneously obtained in order to identify each negative wave in the C recording. The wave of C coincident with that of F was regarded as the far-field potential, and the wave of C′ that diverged from F as the near-field potential at the scalp. There were one negative wave (N 1 ) in the far-field potential and 2 negative waves (N 2 and N 3 1 ) in the near-field potential, after the P 3 component. “N 3 1 ” was conventional N 1 and “N 2 ” was the negative wave just before N31. In infants and younger children, the interpeak latencies of P 3 -N 3 1 and P 3 -N 2 were markedly elongated in comparison with that in older children. These interpeak latencies may be useful as an index of cerebral maturation.