Play and imitation skills in the diagnosis of autism in young children.

Play behaviors and motor imitation skills of 91 children between the ages of 3 and 6 years were investigated to determine their utility in distinguishing autism from mental retardation and other communication disorders. The performance of 22 autistic children was compared with that of 15 mentally retarded, 15 hearing-impaired, 19 language-impaired, and 20 non-handicapped children. Play behaviors were assessed using structured observations of free-play activities, and imitation skills were measured using a set of 12 individually administered tasks. The autistic group spent less total time interacting with toys and using toys appropriately, engaged in fewer functional play acts, and obtained lower imitation scores compared with all other groups. Discriminant function analysis revealed that the latter three variables discriminated the autistic children from the nonautistic handicapped children, with motor imitation emerging as the most important differentiating measure. These results suggest that measuring play and imitation skills may be useful in the clinical diagnosis of autism.