Short latency SEPs in infants and children: developmental changes and maturational index of SEPs.

Short latency SEPs were studied in 56 normal subjects, aged 1 month to 34 years. To identify wave components definitely, simultaneous recordings not only with bipolar leads but also with superimposing methods (comparing the recordings with postcentral- and frontal-non-cephalic references (NC), contralateral to the stimulation side) were obtained in addition to routine recordings with postcentral-NC leads. Four positive (P1, P2, P3 and P4) and 2 negative (N' and N1) peak components were usually identified in all age groups, which represented the developmental changes in their features. By the method of serial representation of SEPs at each age, P1, P2, P3, P4, N' and N1 in children were found to correspond to P9, P11, P13, P14, N18 and N20 in adults, respectively. The features of SEPs in children showed great maturational changes until adolescence when they showed adult patterns. The values of the latencies of P1 and P2 divided by body height, which may be regarded as a maturational index mainly in the peripheral part of the sensory pathway, decreased with age, reaching the adult range at 3-4 years of age. The value of the N1-P3 interpeak latency divided by head circumference, which may be regarded as a maturational index mainly in the central part of the sensory pathway, also decreased with age, reaching the adult range at school age. These indices may be useful in practice for developmental evaluation of the nervous system in children.