The CBIT + TMS trial: study protocol for a two-phase randomized controlled trial testing neuromodulation to augment...

Area of Science:

• Neuroscience
• Clinical Psychology
• Neuromodulation

Background:

• Comprehensive Behavioral Intervention for Tics (CBIT) is a first-line treatment for tic disorders, yet its efficacy is limited to about half of patients.
• The supplementary motor area (SMA) plays a crucial role in motor inhibition and is implicated in tic expression.
• Targeted modulation of the SMA using transcranial magnetic stimulation (TMS) may enhance CBIT effectiveness.

Purpose of the Study:

• To test if augmenting CBIT with TMS targeting the SMA can improve tic controllability in adolescents with chronic tics.
• To investigate if TMS modulation of SMA-mediated circuits enhances the efficacy of CBIT.
• To explore the neural and behavioral mechanisms underlying potential treatment effects.

Main Methods:

• A two-phase, randomized controlled trial (NCT04578912) involving youth aged 12-21 with chronic tics.
• Phase 1 compares two repetitive TMS (rTMS) strategies (1 Hz rTMS vs. continuous theta burst stimulation [cTBS]) against sham stimulation.
• Phase 2 will compare the optimal rTMS regimen against sham, assessing neural target engagement and clinical outcomes.

Main Results:

• This early-stage trial is designed to determine the optimal TMS regimen for augmenting CBIT.
• The study will provide data on the feasibility and potential efficacy of TMS as an add-on therapy for tic disorders.
• Results will inform the link between neural changes in SMA circuits and improvements in tic controllability.

Conclusions:

• This trial is among the first to evaluate TMS augmentation of behavioral therapy in a pediatric population.
• Findings will offer insights into TMS as a viable strategy to enhance CBIT efficacy for tic disorders.
• The study aims to elucidate the neural and behavioral mechanisms driving treatment response.