Automatic and controlled processing in chronic tic disorders

The study compared controlled and automatic processing in 17 people diagnosed with chronic tic disorder (CTD), 20 with habit disorder (HT), and 30 screened controls. Using a countermanding paradigm, time to initiate a response (GO-time) was compared with time taken to inhibit a response (STOP- time) under automated and controlled response conditions. The signals were 2 sets of traffic-light-like computer displays with ready, go, and stop lights. The automated response was a repetitive series of taps and the controlled response was a morse code pattern of taps. There were no group differences in GO time under any conditions. The control group but not the HD or CTD groups showed a significant practice effect over time. The CTD group was significantly slower to STOP the automated than the controlled response. The results suggest that the CTD group had specifically, greater difficulty inhibiting automated than controlled actions. (C) 2000 Academic Press.