Defining the social deficits of autism: the contribution of non-verbal communication measures.

Young autistic children were compared to normal and control samples on measures of non-verbal communication skills and object play skills. Deficits in non-verbal indicating behaviors best discriminated the children diagnosed as autistic from the other groups. Although the autistic children also exhibited deficits in object play behavior, these deficits did not add appreciably to the discriminant function based on the non-verbal communication behaviors. These results suggest that a deficit in the development of non-verbal indicating behaviors is a significant characteristic of young children who receive the diagnosis of autism.