Visual information adds little to heard speech for autism spectrum children
MedWire News: Visual information has a reduced influence on heard speech in children with autism spectrum disorders (ASD) compared with typically developed (TD) children, and may play a role in their language and communication deficits, conclude US physicians.
Sensitivity to audiovisual (AV) speech appears to be present in early development and may be crucial to native language acquisition. As children with ASD often have significant delays in language development, the team hypothesized that a lack of attention to visual speech information may facilitate these deficits.
Complicating the evidence for this is ASD children's characteristic reduction in gaze to the faces of others, remark the researchers, adding: "Thus, it is difficult to determine whether children with ASD detect or integrate visual and auditory information less than TD controls, or whether they neglect visual information because they are not fixated on the speaker's face."
Julia Irwin, from Connecticut State University in New Haven, and colleagues studied 13 children with ASD aged 5-15 years and 13 age-matched TD controls. The participants underwent a battery of tests to assess auditory, visual, and audiovisual speech perception. In addition, the caregivers of children with ASD were interviewed.
The research team reports in the journal Child Development that ASD and TD children were able to identify syllables in the context of auditory noise to a similar degree.
However, during trials in which children fixated on the face of the speaker, those with ASD showed significantly less visual gain compared with TD controls, which suggests that ASD children do not benefit from visible articulatory information as much as TD children. Similar findings were observed in speechreading trials.
The study also demonstrated that children with ASD were significantly less visually influenced than TD children during the mismatched auditory and visual test condition, even when fixating on the face.
Summarizing the findings, the researchers write: "Beginning early in development, young children with ASD likely look less at a speaking face than their typically developing peers. This behavior could lead to weaker AV speech perception, which may have cascading effects on language development.
"In this manner, fundamental differences in attention during social interactions may influence the development of language perception and use."
By Liam Davenport