Quantifying temporal aspects of low-level multisensory processing in children with autism spectrum disorders: a psychophysical study

Abstract

Sensory disturbances and difficulties integrating multisensory information are reported frequently in clinical and autobiographical reports of Autism Spectrum Disorders (ASD); however, there is surprisingly little empirical evidence regarding basic sensory and multisensory functioning in ASD. Perception of sensory and multisensory input requires both spatial and temporal processing. While there is some indication that perception of spatial details may be intact, less is known about the temporal aspects of information processing. This study investigated sensory and multisensory processing and integration of low-level auditory and visual stimuli, with a specific focus on the integrity of temporal processing mechanisms. Rapid temporal discrimination in the auditory and visual modalities was examined first, using standard psychophysical tasks. Next, multisensory integration of cross-modal input was explored by determining whether task-irrelevant auditory information could enhance or interfere with performance on a primarily visual task. Both the strength and the temporal window within which multisensory integration occurred were examined. Results of the study indicated that children with ASD show deficits in rapid temporal processing of both auditory and visual input, relative to children with typical development (TD). Furthermore, children with ASD exhibit multisensory integration to a greater extent and across a wider temporal window than do children with TD. These findings provide empirical evidence for underlying sensory and multisensory processing deficits that may relate to sensory abnormalities reported clinically in individuals with ASD. Atypicalities in the temporal resolution and integration of low-level sensory information may have broader implications for core social, communicative, and behavioral difficulties characterizing ASD.