Altered bodily self-consciousness and peripersonal space in autism

There is some evidence that disordered self-processing in autism spectrum disorders (ASD) is linked to the social impairments characteristic of the condition. To investigate whether bodily self-consciousness is altered in ASD as a result of multisensory processing differences, we tested responses to the full body illusion (FBI) and measured peripersonal space (PPS) in 22 adults with ASD and 29 neurotypical adults. In the FBI setup, participants wore a head mounted display showing a view of their 'virtual body' being stroked synchronously or asynchronously with respect to felt stroking on their back. After stroking, we measured the drift in perceived self-location and self-identification with the virtual body. To assess the PPS boundary we employed an audiotactile reaction time task. Results showed that participants with ASD are markedly less susceptible to the FBI, not demonstrating the illusory self-identification and self-location drift. Strength of self-identification was negatively correlated with severity of autistic traits and contributed positively to empathy scores. Results also demonstrated a significantly smaller PPS, with a sharper (steeper) boundary, in ASD participants. These results suggest that bodily self-consciousness is altered in participants with ASD due to differences in multisensory integration, and this may be linked to deficits in social functioning.