Brain-behavior relations during motor processing in chronic tic and habit disorder.

OBJECTIVE This study examined electrophysiological indices of preparation (readiness potential, RP) and execution (movement-associated potential, MAP) during automated and controlled reaction time (RT) in 13 chronic tic disorder, 17 habit disorder, and 14 control participants. BACKGROUND Both tic and habit disorders are hypothesized to involve states of heightened activation, which could impede initiation and the control of complex motor actions. METHOD The electrophysiological signal was recorded from 4 electrodes (Fz, C3, C4, Pz) during a fixed 4-second foreperiod reaction time task. RESULTS During automated responses, controls showed a shorter RP peak onset, and during controlled responses a longer MAP peak onset, compared with both clinical groups. The controls were the only group who showed a consistent linear relationship between RP and RT. CONCLUSIONS Patients with chronic tic as well as habit disorder may not modulate cortical activation optimally in planning and executing both automated and controlled responses.