TICS: Transcranial Magnetic Stimulation for Intervening in Children With Tourette's Syndrome (CIHR)

Tourette's Syndrome (TS) is characterized by repetitive movements and vocalizations called tics. Due to the suffering caused by TS, children and adolescents often require treatment for their tics. The investigators' research focuses on developing novel repetitive transcranial magnetic stimulation (rTMS) interventions for child and adolescent neuropsychiatric disorders. In this project, the investigators will determine the effect of pairing 3 weeks of rTMS and HRT on tic severity and plasticity as indexed by supplementary motor area (SMA) y-aminobutyric acid (GABA) concentration and functional connectivity of the SMA to the primary motor cortex (M1) in children and adolescents with TS. Children (N = 50, 6-18 years) with TS will be randomized to either a (1) rTMS+HRT arm, or (2) sham rTMS+HRT. Outcome measures will examine tic severity (primary), brain chemistry and function (secondary) at baseline and then at week 7. The investigators' proposed aims are: (Aim 1) To determine the effect of paired rTMS and HRT on tic severity as measured by the Yale Global Tic Severity Scale (YGTSS) by comparing it to sham rTMS + HRT. 1-1: The investigators hypothesize that tic severity will decrease from baseline to post-treatment. 1-2: The investigators also hypothesize that the reduction in tic severity will be greater in the paired treatment group (rTMS+HRT \> Sham rTMS+HRT). (Aim 2) To determine the effect of paired rTMS and HRT on brain plasticity compared to sham rTMS + HRT. 2-1: The investigators hypothesize that patients treated with the paired rTMS and HRT will have a greater increase in GABA concentration comparted to sham and HRT. 2-2: The investigators also hypothesize that functional connectivity between the SMA and M1 will be greater with paired treatment (rTMS+HRT \> Sham rTMS+HRT).