Brainstem auditory evoked potential abnormalities in myelomeningocoele in the older child.

Brainstem auditory evoked potentials and clinical findings were examined in 18 children over the age of 5 years who were born with myelomeningocoele which was closed at birth, and whose hydrocephalus was managed by long term shunting in most of them. The potentials were compared with age and sex matched normal subjects and with four patients with hydrocephalus only. All but one had an abnormal brainstem auditory evoked potential with 72% showing a delay in the II-V and I-V interpeak latencies of more than three standard deviations. It is proposed that the abnormalities are a reflection of brainstem dysgenesis which is part of an associated Arnold-Chiari malformation, though the malformation was clinically asymptomatic in all. The usefulness of the brainstem auditory evoked potential for assessing the course of hydrocephalus and for predicting symptomatic Arnold-Chiari malformation is questioned.