To compare right frontal event-related spectral perturbation (ERSP) during cognitive control tasks in youth with TS versus controls and to determine if this ESRP (i.e. synchronization vs. desynchronization) correlates with tic severity or tic suppression capability.

Physiologic differences in the right frontal lobe, an important region for motor inhibition, have been described in Tourette syndrome (TS) as a compensatory adaptation for tic suppression.

Fourteen TS and thirteen healthy control children (10-17 years old) completed a Slater-Hammel stop-signal reaction time (SSRT) task (160 trials; 2 GO: 1 STOP trial ratio) with the right hand while high-density electroencephalography was recorded. After wavelet analysis and source localization, between-group right superiorfrontal (RSF) and inferiorfrontal (RIFG) ERSP (3-50 Hz) differences were evaluated. In TS, correlation analysis was conducted to examine the relationship between frequency-specific ERSP vs. clinical (Yale Global Tic Severity Scale, self-reported tic suppressibility) and behavioral (SSRT) data.

There was no group difference in SSRT or successful stop trial ERSP. In TS, there was greater event-related desynchronization (ERD) in the RSF (γ band) and RIFG regions (θ, α, β, γ bands) prior to decision-making on motor execution/inhibition. These γ ERD correlated with tic severity (RSF; ρ=0.56, p=0.04) while inverse correlation with self-reported tic suppressibility was at trend level (RIFG; ρ=-0.63, p=0.08). No significant correlation with SSRT was found.

TS patients exhibited greater ERD in the right frontal regions in our stop-signal task. The extent of right frontal γ-ERD correlated with clinical measures suggesting this physiologic finding may represent a compensatory process. Our findings suggest that RSF region may play an adaptative role, resulting in decreased tic severity, while RIFG may play an active role in tic suppression. Longitudinal investigation of this potential biomarker may provide deeper understanding of TS natural history.