Non-significance of early speech delay in children with autism and normal intelligence and implications for DSM-IV Asperger’s disorder

Dickerson Mayes, S. and Calhoun, S.L. (2001) Autism Vol 5 (1) 81-94.

According to the DSM-IV, children with Asperger’s disorder do not have significant cognitive or speech delays, whereas children with autistic disorder may or may not. In our study, children with normal intelligence who had clinical diagnoses of autism or Asperger syndrome were divided into two groups: those with and without significant speech delay. The purpose was to determine if clinically meaningful differences existed between the two groups that would support absence of speech delay as a DSM-IV criterion for Asperger’s disorder. No significant differences were found between the 23 children with a speech delay and the 24 children without a speech delay on any of the 71 variables analysed, including autistic symptoms and expressive language. Results suggest that early speech delay may be irrelevant to later functioning in children who have normal intelligence delay as a DSM-IV distinction between Asperger’s disorder and autism may not be justified.

Discussion
Research to date has failed to support the validity or existence of Asperger’s disorder as defined by the DSM-IV.

Simply changing the DSM-IV cutpoints for significant speech and cognitive delays would not alter these findings. All 157 children in the author’s study who had clinical diagnoses of autism or Asperger’s syndrome or disorder met the DSM-IV criteria for autism and not Asperger’s disorder, irrespective of the presence or degree of speech and cognitive delays.

High-functioning autism is already covered in the DSM-IV by an axis I diagnosis of autistic disorder without mental retardation coded on axis II. If Asperger’s disorder is indeed high functioning autism and not a diagnostic entity separate and distinct from autism, Asperger’s disorder should not be included in the next version of the DSM.