A DIMENSIONAL CLASSIFICATION OF AUTISM SPECTRUM DISORDER BY SOCIAL COMMUNICATION DOMAINS

Objective: To investigate whether ''social communication'' could be us ed to assess severity of symptoms in autism spectrum disorder. Social communication refers to the communication of cognitive and emotional i nformation through facial expression, gesture, and prosody and through implicit understanding of pragmatics and of theory of mind. Method: S ubjects were evaluated by raters using the Autism Diagnostic Interview -Revised and either the Autism Diagnostic Observation Schedule or the Pre-Linguistic Autism Diagnostic Observation Schedule. Two investigato rs independently diagnosed autism, Asperger's disorder, or pervasive d evelopmental disorder-not otherwise specified in 63 subjects. Items fr om the Autism Diagnostic Interview-Revised that were judged to represe nt social communication behaviors were factor-analyzed, Results: Three factors were identified: affective reciprocity, joint attention, and theory of mind. Comparing this new classification approach to DSM-IV l ed to suggestions for possible changes in the latter: (1) Vocabulary a nd grammar deficiencies in autistic persons should be coded under deve lopmental language disorder. (2) The diagnosis of Asperger's disorder may not be needed. (3) Requiring that all persons with autism spectrum disorder have a symptom from the ''restrictive, repetitive, and stere otypic'' list may need to be reconsidered. Conclusions: The DSM-IV cat egory of pervasive developmental disorder may be ideal for diagnosing ''classic'' autism, but it may be inadequate for diagnosing less sever e forms of the disorder.