ABSTRACT
To determine executive dysfunctions in children with autistic disorder or attention-deficit/hyperactivity disorder (ADHD), we investigated high-functioning autistic (full scale IQ score >or==70), ADHD, and control children using the computerized version of the Wisconsin Card Sorting Test. Data were obtained from 17 autistic children (16 boys and 1 girl, mean age+/-SD: 12.5+/-4.3), 22 ADHD children (20 boys and 2 girls, mean age+/-SD 11.3+/-2.6), and 25 control children (13 boys and 12 girls, mean age+/-SD: 12.7+/-3.1). Performances, indicated by mean number of categories achieved (5.4 in autistic, 6.5 in ADHD, and 8.8 in control group), total errors (38.2, 38.4, and 25.6, respectively), perseverative errors (11.4, 13.5, and 5.7), nonperseverative errors (27.1, 25.0, and 19.9), and Nelson type perseverative errors (8.9, 8.4, and 2.3), were significantly poorer in both autistic and ADHD groups than control group (P<0.01). Comparing the autistic group to the ADHD group, there were no significant differences in age, gender, scores of full-scale intelligent quotient (IQ), verbal or performance IQ, number of categories achieved or errors. The ADHD group, however, showed more frequent Milner type perseverative errors than the autistic group (P<0.05). The present study suggests that some kinds of executive function are more impaired in children with ADHD than in those with high-functioning autism, and that Milner type perseverative errors is useful parameter to differentiate the executive dysfunctions between autistic and ADHD children.