Slowed reaction time during a continuous performance test in children with Tourette's syndrome.

The phenomonology of Tourette's syndrome (TS) not only includes tics but also apparent deficits in attention. These attentional deficits in TS likely involve anomalies in frontal-striatal circuits. In this study, performance of 22 boys with TS and 22 age-matched boys without TS was compared on a continuous performance test (CPT) of attention. TS children demonstrated a normal capacity for discriminating targets from nontargets during the task, but showed significantly slower reaction times than controls. Severity of complex vocal tics was predictive of reaction time performance. Possible explanations for these findings are discussed and include the presence of attentional difficulties in TS, interference associated with tic suppression, a conservative strategy taken by TS children, and a general impairment of motor performance.