Characteristics of auditory brainstem response latencies in children with autism spectrum disorders

Abstract Background: Hypersensitivity to loud sounds is commonly noticed in children with autism spectrum disorders. Objective and methods: This was a cross-sectional study that included 50 children, ages ranging from 1.5 to 3.33 years, divided into a study group of 25 autistic children with normal hearing and a control group of 25 normal hearing healthy children. The aim of this research was to the assess any abnormality in the loudness growth function objectively using auditory brainstem response (ABR), as well as to detect any ABR abnormalities in normal hearing autistic children with delayed language development. Results: Forty-four percent of normal hearing autistic children showed a lower threshold compared to healthy controls. They also showed significantly delayed wave III, but within-normal wave V, and consequently a longer inter-peak interval (IPI): I–III and shorter IPI: III–V, reflecting retro-cochlear dysfunction that may be related to their difficulty in communication. The mean slope of wave V latency intensity curve did not differ between autism and their controls, reflecting normal loudness growth. Male autistic children showed statistically significant longer latencies of wave V than females except at high intensities, but there was no statistically significant difference between them with regard to the mean slope of wave V latency intensity curve. Conclusion: Autistic children with normal hearing showed a within-normal loudness growth indicating that their abnormal reactions to sounds may either be phonophobia, an efferent system affection or a more central pathology that needs further evaluation. They also showed a retro-cochlear dysfunction that may be related to their difficulty in communication.