A comparative study of infantile autism and specific developmental receptive language disorders III. Discriminant function analysis

A psychometric, observational, and interview study was undertaken with 47 boys, aged 4 1/2 to 10 years, with nonverbal IQs of 70+ and a severe developmental disorder of language comprehension. Separate discriminant function analyses, based on behavioral, language, or cognitive features, showed little overlap between clinically defined autistic and dysphasic subgroups. Moreover, the discrimination could be made as clearly on language or cognitive characteristics as on social or behavioral criteria. Language abnormalities and behavioral features also intercorrelated within the autistic subgroup. It is concluded that autism and dysphasia differ in important ways and that a cognitive deficit is an essential part of the syndrome of autism.This study was supported in part by grants from the Department of Education and Science and the Bethlem-Maudsley Hospital Research Fund. We are very grateful to the Directors and staff of the Units from which cases were selected for their ready cooperation in allowing us to examine children in each Unit. All went out of their way to provide help throughout the investigation. We are especially grateful to the parents of the children for their forbearance in allowing us to interview them at considerable length and for their exceptional kindness to individual investigators. We are also very grateful to Mr. B. S. Everitt of the Biometrics Department, Institute of Psychiatry, for statistical advice.