Hemispheric specialization and the language abilities of autistic children

The purpose of the present study was to investigate the relationship between patterns of hemispheric specialization for speech processing and language ability in autistic children. 17 male autistic children, 6-18 years of age, and 17 normal children, matched for chronological age and gender, were tested. Measures of hemispheric asymmetry were differences in the averaged cortical evoked responses taken from right and left hemisphere scalp locations to linguistic and nonlinguistic auditory stimuli. A comprehensive battery of language tests was administered to autistic subjects. Autistic children's direction of hemispheric asymmetry in response to linguistic stimuli differed significantly from that of normal subjects. The majority of autistic subjects showed reversed (right hemisphere dominant), but not necessarily reduced, patterns of hemispheric asymmetry. Autistic children with more advanced language abilities were more likely to exhibit a normal direction of hemispheric asymmetry. The possibility that a shift from right to left hemisphere processing of speech occurs as the autistic child acquires spoken language is discussed.