The effect of visual spatial attention on audiovisual speech perception in adults with Asperger syndrome.

Individuals with Asperger syndrome (AS) have problems in following conversation, especially in the situations where several people are talking. This might result from impairments in audiovisual speech perception, especially from difficulties in focusing attention to speech-relevant visual information and ignoring distracting information. We studied the effect of visual spatial attention on the audiovisual speech perception of adult individuals with AS and matched control participants. Two faces were presented side by side, one uttering /aka/ and the other /ata/, while an auditory stimulus of /apa/ was played. The participants fixated on a central cross and directed their attention to the face that an arrow pointed to, reporting which consonant they heard. We hypothesized that the adults with AS would be more distracted by a competing talking face than the controls. Instead, they were able to covertly attend to the talking face, and they were as distracted by a competing face as the controls. Independently of the attentional effect, there was a qualitative difference in audiovisual speech perception: when the visual articulation was /aka/, the control participants heard /aka/ almost exclusively, while the participants with AS heard frequently /ata/. This finding may relate to difficulties in face-to-face communication in AS.