[Speech development and intelligence in autism. How uniform is Asperger syndrome?]

Since the introduction of a separate diagnosis for Asperger's syndrome in the ICD-10 and DSM-IV classification systems, a controversial debate has continued on whether Asperger's syndrome is a specific, clearly distinguishable disorder within the autistic spectrum or whether it represents a milder phenotypical variation of autism. The effect on the amount of autistic symptoms of the variables language delay and level of intelligence was analyzed within a sample of individuals exhibiting autism diagnosed by standardized methods. Both variables showed a significant effect on the degree of autistic symptoms in that impairments in social interaction were less noticeable. In addition, a subsample of individuals exhibited symptoms assumed to be characteristic for Asperger's syndrome. The findings support the assumption that autism and Asperger's syndrome represent "extreme points" on a scale of severity, which leads to the suggestion that the classification of different subtypes of autism could be abandoned in favor of a dimensional (multiaxial) approach.