Effects of age on communication skill levels and prevalence of maladaptive behaviors in autistic and mentally retarded children.

This study investigated the effect of age on communication and maladaptive behavior in autistic and mentally retarded children. Forty-seven autistic and 128 mentally retarded children in a special school served as subjects. The cross-sectional method was used to compare junior and senior groups, and ratings on communication skills and maladaptive behaviors were obtained from teachers. We found that the skills of comprehension and conversation in autistic children improved significantly with age, and speech improved somewhat. In spite of this improvement in communication skills, maladaptive behaviors in the autistic children other than hyperactivity did not change significantly with age. Withdrawal improved significantly with age in the mentally retarded children but not in the autistic children.