Cognitive, behavior and intervention outcome in young children with autism.

UNLABELLED: The relations between cognition and autism severity, head size and intervention outcome, were examined. Change in cognitive level with intervention was measured in children with autism and compared to children with developmental disabilities (DD). Eighty-one children (mean age 25.9 months) with autism (n=44) and DD (n=37) were assessed at pre- and post 1 year of intervention. Cognitive abilities and autism severity were measured by standardized tests. Three pre-intervention cognitive level groups: normal (IQ>90), borderline (70<IQ<89) and impaired (50<IQ<69) were examined. The impaired group had more severe autism symptoms than the borderline and the normal cognitive groups. However, following intervention the groups did not differ in the change in core autism symptoms. IQ scores increased significantly more in the autism group than in the DD group. IQ improvements correlated significantly with reduction in autism symptoms and mostly in stereotyped behaviors.

CONCLUSIONS: Cognitive ability in autism is associated with autism severity. Two distinct subtypes based on cognitive level are identified. However, baseline cognitive level cannot predict the progress rate in autism symptoms with intervention. Improvement of social-communicative behaviors and the intensive intervention are related to significant cognitive increments in autism.