Neuropsychological functioning in children with Tourette syndrome with and without attention-deficit/hyperactivity disorder.
OBJECTIVE
Neuropsychological functioning in children with Tourette syndrome (TS) has been characterized by subtle deficits in response inhibition, visual-motor integration, and fine-motor coordination. The association of these deficits with the tics of the TS versus co-occurring attention-deficit/hyperactivity disorder (ADHD) has not been well understood because of small sample sizes and lack of adequate control conditions. We examined neuropsychological functioning in relatively large and well-characterized samples of children categorized as TS, TS-plus-ADHD, ADHD, and unaffected controls.


METHODS
A total of 56 children with TS-only, 45 with TS-plus-ADHD, 64 with ADHD, and 71 healthy community control subjects were assessed on a battery of neuropsychological measures including the Connors' Continuous Performance Test (CPT), the Stroop Color-Word Interference Test (Stroop), the Beery Visual-Motor Integration Test (VMI), and the Purdue Pegboard Test.


RESULTS
There were no differences between children with TS-only and unaffected controls on the measures of response inhibition and visual-motor integration. Boys with TS-only but not girls with TS-only were impaired in the dominant hand Purdue performance. Children with ADHD were impaired on all study measures. Children with TS-plus-ADHD revealed no deficits on the Stroop, VMI, and Purdue tests but were impaired on the sustained attention portion of the CPT.


CONCLUSIONS
These results indicate that co-occurring ADHD may be responsible for the neuropsychological deficits, or at least those assessed in the present study, in children with TS. Explanations in terms of neurobiological mechanisms of co-occurring TS and ADHD, as well as possible compensatory mechanisms in children with TS, are discussed.
Yale Child Study Center, 230 South Frontage Road, PO Box 207900, New Haven, CT 06520-7900, USA. denis.sukhodolsky@yale.edu
Denis G
DG
Sukhodolsky
Angeli
A
Landeros-Weisenberger
Lawrence
L
Scahill
James F
JF
Leckman
Robert T
RT
Schultz
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000175:diagnosis / Q000523:psychology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011595:Psychomotor Agitation; D011597:Psychomotor Performance; D011931:Reactive Inhibition; D012720:Severity of Illness Index; D005879:Tourette Syndrome / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology