The use of the ADI-R as a diagnostic tool in the differential diagnosis of children with infantile autism and children with a receptive language disorder.

Children with infantile autism and children with a specific receptive language disorder often show similar behavioural problems, making the differentiation between these two diagnostic categories difficult. The purpose of this study is to evaluate the usefulness of parental information in the differential diagnosis of the two types of disorders mentioned above. Sixteen children with a receptive language disorder and 11 children with infantile autism participated in the study. All children had normal non-verbal IQs. The ADI-R (Autism Diagnostic Interview-Revised) was performed with all children. The results showed that the ADI-R items reflecting behavioural features at pre-school age (age range 4-5 years) were better suited to differentiate the groups than the items reflecting behavioural features at the time of the investigation (mean age: 9 years). The items on the dimension "Reciprocal social interaction" and "Communication and language" discriminated the groups better than the items of the dimension "Restricted interests". According to the ICD-10 algorithm of the ADI-R one child with autism and one child with a receptive language disorder were falsely classified. These false classifications were mainly due to a distorted parental perception of the child's behaviour. The ADI-R is a useful tool in the differential diagnosis of developmental disorders.