A comparative study of Asperger syndrome with high-functioning atypical autism.

To test the validity of Asperger syndrome (AS) as defined in ICD-10, 26 patients (age range, 3.5 to 12 years) with AS and 16 patients (age range, 3 to 11.5 years) with high-functioning (IQ > 90) ICD-10 atypical autism (HAA) were compared on 64 clinical variables including obstetric risk factors, early developmental landmarks, IQ, autistic symptoms on the CARS-TV, epileptic EEG abnormalities and epilepsy. AS did not differ significantly from HAA on all but total and four item scores (i.e. imitation, visual responsiveness, auditory responsiveness and non-verbal communication) on the CARS-TV, in which AS scored significantly lower than HAA. A discriminant function based on imitation and auditory responsiveness predicted 76.2% of the 42 cases. The small difference from HAA indicates that AS is better to be regarded as the highest-functioning end of the PDD spectrum, rather than a valid subtype of PDD. However, the autistic symptom profile less distorted in AS than HAA may warrant a further study on its validity.