fMRI-guided TMS with trihexyphenidyl for neck movement in cervical dystonia

This study aims to investigate the impact of accelerated transcranial magnetic stimulation (TMS) on brain function and behavior in patients with focal cervical dystonia. Previous research demonstrated that individualized TMS improved writing behavior in focal hand dystonia after one session. In this study, we aim to expand the application on TMS on focal cervical dystonia. The current study administers six sessions of TMS separated by five rest blocks, all in a single day and combined with a medication called trihexyphenidyl given 30 minutes before the TMS session. This approach is called "anticholinergic enhanced accelerated TMS The research involves 8 in-person visits and 3 remote visits over 28 weeks. The effect of TMS will be assessed using functional MRI brain scans and behavioral measurements. Participants who are interested in enrolling in the TMS study to assess their potential presurgical response to DBS will only receive the active TMS session combined with trihexyphenidyl medication. After active TMS + trihexyphenidyl medication, participants will be followed for 3-5months to assess their brain and behavior response to TMS. Following clinical care DBS, participants will be followed for three additional research visits. The three visits will be performed at 1 month, 3 months and 6-9 months. During the post-DBS research visits, participants will complete behavioral assay and physiological assay to evaluate their neck movements and muscles. At 3 month or 6-9 month visit, the post-DBS participants will also undergo fMRI with the DBS device in off mode setting.

The risk of TMS includes seizures; the potential risk of seizures from TMS is mitigated through careful screening, adhering to safety guidelines. The study's main benefit is enhancing dystonic behavior and deepening the understanding of brain changes caused by TMS in cervical dystonia, paving the way for further advancements in clinical therapy for this condition.