Outcome in high-functioning adults with autism with and without early language delays: implications for the differentiation between autism and Asperger syndrome.

The question of whether Asperger syndrome and high-functioning autism should be considered as the same or different conditions has been a source of debate and controversy over recent years. In the present study, 34 adults with autism who had shown early delays in language were compared with 42 individuals who were reported to have had no such delays, either in their use of words or phrases. All participants were at least 18 years of age, had a nonverbal IQ of 70 or above and met ADI-R criteria for age of onset, communication and social impairments, and stereotyped behaviors. Those in the language delay group were diagnosed as having high-functioning autism. The remainder were designated as having Asperger syndrome. The groups were matched for age, nonverbal IQ and gender. No significant differences were found between the groups either in their total ADI-R algorithm scores, or in their algorithm scores on individual domains. Social outcome ratings and ADI-R scores based on current functioning also failed to differentiate between the groups. Scores on tests of language comprehension and expression were also similar, but in both groups language abilities were well below chronological age level. The implications of these results with respect to the differences between Asperger syndrome and high-functioning autism are discussed. The poor performance on language tests also challenges the assumption that early language development in Asperger syndrome is essentially normal.