Durability, negative impact, and neuropsychological predictors of tic suppression in children with chronic tic disorder.

Chronic tic disorders are characterized by involuntary motor and vocal tics, which are influenced by contextual factors. Recent research has shown that (a) children can suppress tics for brief periods of time, (b) suppression is enhanced when programmed reinforcement is provided for tic-free intervals, and (c) short periods of suppression do not result in a paradoxical "rebound" in tic frequency when active suppression has ceased. The current study extended existing research in three important ways. First, we examined whether tic suppression ability decreased as suppression duration increased from 5 to 25 to 40 min. Second, we examined post-suppression tic frequency to test whether longer periods of suppression were more likely to be associated with a rebound effect. Finally, we explored neuropsychological predictors of tic suppression. Thirteen children with Tourette syndrome or a chronic tic disorder completed the study. Results showed that (a) tic suppression was sustained for all of the suppression durations, (b) rebound effects were not observed following any of the suppression durations, and (c) ability to suppress was correlated with omission, but not commission errors on a continuous performance task. Implications of these findings are discussed.