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.