Do You See What I'm Saying? Deficits in the Visual Enhancement of Speech Comprehension Under Noisy Environmental Conditions in Autism

Background: Viewing a speaker's articulatory movements substantially improves a listener's ability to understand spoken words, and this is especially so under noisy environmental conditions. In this study we investigated the ability of children with autism to effectively integrate visual and auditory speech. Multisensory integration deficits have long been theorized in ASD but as yet, very little empirical work actually exists to support this notion.

Objectives: Our objective was to determine to what extent children with ASD experience benefit from visual articulation and to detail under what listening conditions they might show the greatest audiovisual multisensory impairments.

Methods: We assessed the ability to recognize auditory-alone and audiovisual speech embedded in different levels of background noise in 7 high functioning children with autism and compared their performance with that of 12 age-matched typically developing children. We used a large set of monosyllabic words as our stimuli in order to closely approximate performance in everyday situations.

Results: Children with autism showed clear deficits in their ability to derive benefit from visual articulatory motion. This multisensory impairment was most pronounced at the lowest signal-to-noise levels. That is, at the lowest levels of background noise, ASD children were the least affected and did show evidence of multisensory integration, whereas their performance was impacted to a progressively greater degree as the level of background noise was increased.

Conclusions: These results reveal a specific deficit in multisensory speech processing in children with autism and suggest that this multisensory deficit is greatest when the environment is at its noisiest or most confusing. We conclude that multisensory integration dysfunction is likely an important aspect of autism spectrum disorder (ASD).