Objectives: We investigated the electrophysiological neural correlates of eye gaze processing and their interaction with facial expressions in children with ASD and typically developing controls. This paradigm has successfully been used with infants (Striano, Grossman, Kopp, Reid, 2006).
Methods: We measured event-related brain potentials (ERPs) in 7 children with ASD (6.8 - 9.5 years; 1 female) and 7 age and gender matched controls. We presented children with pictures of angry or neutral facial expressions with direct or averted eye gaze. Data analyses were carried out for the face processing ERP component N170.
Results: There were several significant findings:
1. Among children with autism, there was a more negative amplitude for direct compared to averted gaze in the right hemisphere.
2. Compared to the control group, among the children with autism, the N170 peaked later for angry compared to neutral facial expressions.
3. Among the typically developing children, angry faces with direct gaze elicited a greater negativity compared to neutral.
Conclusions: Children diagnosed with autism processed eye gaze and facial expressions differently. First, children with autism showed a different N170 response for eye gaze processing compared to controls. This response is close to the one displayed by infants. Second, children with ASD showed delayed neural processing for angry compared to neutral, whereas typically developing showed increased processing for angry compared to neutral. In general, the findings show a differential pattern of the N170 suggesting delayed development with differential processing for eye gaze and emotion in school-aged children with ASD. These findings may be used to aid in the development of new diagnostic tools.