Introduction. Treatments for Tourette’s syndrome (TS) are limited and risk possible side effects; new interventions are needed. Repetitive transcranial magnetic stimulation (rTMS) non-invasively modulates targeted brain regions with potential therapeutic effects. The goal of this study is to determine the effects of fMRI-guided, low frequency rTMS of the supplementary motor area (SMA) on tic severity and underlying neurobiology in children with TS.

Methods. Children aged 6-18 with severe TS are recruited from a pediatric TS clinic. Motor task fMRI generates maps of the SMA that are uploaded to a TMS neuro-navigation system (Brainsight2) synchronized with a TMS robot, allowing precise, individualized targeting of the SMA. Open label treatment consists of 1800 low frequency (1 Hz) rTMS stimulations to the SMA bilaterally for 15 days. The primary outcome is TS symptom change. Additional outcomes include mental health scales, MR spectroscopy, motor mapping, and tolerability. All measures are completed at baseline and post-treatment.

Results. The first nine participants are presented (age 9-15, median age 11, 2 female). A decrease in tic severity was found following treatment (mean 59% (SD=17) decrease pre to post, p=0.01). Spectroscopy analysis showed possible trends of increased GABA and decreased glutamate concentrations in the SMA and primary motor area of the dominant hand hemisphere. Motor maps also appear to change with stimulation. Procedures were well-tolerated.

Conclusion. Robot-driven, personalized, neuro-navigated rTMS interventions appear feasible in children with TS. Ancillary tools including neuroimaging may inform mechanisms of action. Completion of this and future randomized trials are required to demonstrate efficacy.