Prolonged brainstem transmission time in autism.

Brainstem auditory evoked potentials (BAEPs) to clicks presented monaurally were gathered for 16 institutionalized children with a prior diagnosis of autism and with no hearing loss as tested by standard audiometry. Twenty age-matched normal children served as controls. Brainstem transmission time, defined as BAEP interpeak I-V latency, was prolonged significantly on the average in the autistic sample on both left and right sides. Individually, BAEPs for 9 of the 16 autistic children (or 56%) on whom some electrophysiological data were gathered were classified as abnormal when compared to the norms established in the control group. The most common BAEP abnormality was a prolonged interpeak III-V latency on the left side.