Subthreshold rTMS over pre-motor cortex has no effect on tics in patients with Gilles de la Tourette syndrome

Objective: A previous study showed no effect of 1 Hz repetitive transcranial magnetic stimulation (rTMS) on tics in Gilles de la Tourette Syndrome (GTS). We modified the rTMS protocol in order to investigate some of the possible methodological reasons for the negative outcome in that study. Methods: In a single blinded placebo-controlled cross-over study in five GTS patients without obsessive compulsive disorder we probed whether longer trains (1800 stimuli) of 1 Hz pre-motor cortex rTMS at 80% of active motor threshold and application to both hemispheres can improve tics in GTS. This was measured with the Yale Global Tic severity rating scale, the MOVES self-rating scale and video analysis. Results: We found no significant effect of either left pre-motor cortex stimulation alone, or left pre-motor followed by right pre-motor cortex stimulation. Conclusions: These results suggest that the rTMS protocol used in this study is not useful for the treatment of tics in GTS. Significance: rTMS protocols need to be modified substantially in order to explore their potential for the treatment of tics in GTS.