Auditory brainstem response abnormalities in autistic children.

In an attempt to clarify issues of brainstem dysfunction and hearing thresholds in autistic children, we studied the Auditory Brainstem Responses (ABRs) in 32 children who clearly fit within the criteria of autism established by the National Society for Autistic Children (1977). ABRs were recorded between Cz and ipsilateral ear in response to click stimuli. Interwave latencies and auditory threshold in each ear were determined. Of the 32 children, 11 had moderate hearing loss (8 bilaterally) and 3 had severe to profound hearing loss, all bilaterally. 8 of the 14 with hearing loss also had associated features (e.g., perinatal encephalopathy). The I-III and I-V interwave latencies were significantly longer in the autistic children compared to normal control children; the increased conduction times were found mainly in the early portion of the auditory brainstem pathway. These data confirm some earlier reports of ABR abnormalities in autistic children and are concordant with some theories of the etiological basis of autism. The high incidence of hearing loss in these children is significant and routine ABR testing is recommended.