Auditory brainstem responses in adults with autism spectrum disorder.

OBJECTIVE: To investigate possible differences in the auditory peripheral and brainstem functions between adults with autism spectrum disorder (ASD) and neurotypical (NT) adults. METHODS: Click-evoked auditory brainstem responses (ABRs) were obtained from 17 high-functioning ASD adults (aged 21-38 years) and 20 NT adults (aged 22-36 years). A relatively large number of stimulus presentations (6000) were adopted, and ABRs by horizontal and vertical electrode montages were evaluated, in order to allow precise evaluations of early ABR components. RESULTS: Waves I, II, III, and V were identified in the vertical electrode montage, and wave I and the summating potential (SP) in electrocochleograms were identified in the horizontal electrode montage. There were no significant group differences in the wave I, II, III, and V latencies or the interpeak latencies (IPLs) in the vertical electrode montage. In the horizontal montage, the ASD adults exhibited significantly shortened SP latencies compared with the NT adults, whereas there was no significant group difference in the wave I latency. CONCLUSION: The ASD adults may have the abnormalities of processing more in the peripheral auditory system than in the brainstem. SIGNIFICANCE: The current study suggests that the peripheral abnormality is associated with ASD.