Neuropsychological performance in children with Tourette's syndrome.

Neuropsychological performance was examined in a sample of 100 children between the ages of 6 and 18 years who met DSM-III-R criteria for Tourette's syndrome. Neuropsychological test scores were converted to age-corrected t scores based on published normative data. Ratings of Tourette's symptoms were also obtained. The mean IQ of the sample was approximately 100. Most of the subjects performed within normal limits, although approximately 20% obtained scores suggesting impairment on a summary neuropsychological performance measure. There were no differences attributable to medication effects. Later age at onset and the severity of complex tics were related to performance below normal levels on a number of neuropsychological measures. There was no specific evidence of frontal lobe dysfunction. The pattern of neuropsychological performance was virtually identical to a previously reported independent sample of patients. These data suggest a relatively characteristic pattern of neuropsychological performance abnormalities in a subgroup of patients with Tourette's syndrome. In general, most patients appear to perform within normal limits. Directions for future investigation are considered.