Natural course of brainstem auditory evoked potentials in infants less than 6 months old with asymptomatic meningomyelocele.

It is difficult to estimate the accurate onset of symptoms clinically resulting from Chiari II malformation. Brainstem auditory evoked potentials (BAEPs) may be a useful method in the selection of potential candidates for surgery. We studied 153 BAEPs in 131 asymptomatic infants under 6 months of age with meningomyelocele (MMC). Both the wave latencies and interpeak latencies (IPLs) gradually became shorter during the first 6 months of life in asymptomatic infants with MMC. In particular, shortening of the III-V IPLs and the I-V IPLs was observed from 1 to 4-6 months of age in these infants. These may be characteristic parameters of central auditory function (III-V IPLs) and global auditory function (I-V IPLs). Maturation of brainstem function as viewed by BAEPs in asymptomatic infants with MMC was delayed when compared to data in normal neonates and infants. These data on asymptomatic infants with MMC could potentially be a good reference for selecting the modalities of treatment in infants with symptomatic Chiari II malformation.