Auditory processing and its relation to cognitive and language ability across the autism spectrum

Abstract

Individuals with autism spectrum conditions (ASC) often demonstrate enhanced discrimination of basic perceptual information such as pitch. This thesis investigated whether this enhanced perceptual tendency is limited to low-level acoustic stimuli or whether it occurs in higher-level linguistic stimuli in areas other than pitch and in speech-like sounds in adults with ASC who were individually matched on IQ to typically-developed adults. It tested whether differences in auditory discrimination and identification ability were related to aspects of language ability. It also tested whether IQ had an independent or an additive influence on performance differences and relationships. These effects were additionally explored with autistic traits in typically-developed adults in which IQ and linguistic skills are less variable than those within the ASC population. It was found that discrimination and identification ability of auditory stimuli were not enhanced but were related to IQ and some aspects of language ability. In ASC, previous reports of discrimination and identification differences may be attributable to an additive influence of IQ and some of the language difficulties may be explained by differences in the ability to discriminate and identify perceptual information in speech. These findings may impact on identifying and providing targeted language intervention in ASC.