Evaluation of EEG biomarkers of Comprehensive Behavioral Intervention for Tics in children with Tourette syndrome.

OBJECTIVE: Comprehensive Behavioral Intervention for Tics (CBIT) is a first-line treatment of Tourette syndrome (TS). However, the brain mechanisms involved in CBIT are poorly understood. Enhanced frontomesial EEG coherence during a Go/NoGo task has been suggested as a mechanism involved in voluntary tic control. In the current study, we conducted a randomized controlled trial to assess whether EEG coherence during a Go/NoGo task was associated with CBIT outcome. METHODS: Thirty-two children with TS were randomly assigned to CBIT or to treatment-as-usual (TAU). Treatment outcome was assessed by a blinded evaluator with the Yale Global Tic Severity Scale (YGTSS) and the Clinical Global Impression - Improvement Scale (CGI-I). EEG was recorded during a Go/NoGo task at baseline and endpoint. EEG coherence was computed in the alpha frequency band between a priori selected channel pairs spanning the frontal and motor areas. RESULTS: Tic severity decreased significantly in the CBIT group. However, CBIT did not impact EEG coherence and baseline EEG coherence did not predict treatment outcome. CONCLUSIONS: Although CBIT was superior to TAU on blinded clinical outcomes, EEG coherence during the Go/NoGo task was not associated with change in tic severity. SIGNIFICANCE: The brain processes involved in the inhibition of motor responses do not appear to be involved in CBIT.