Category: Dystonia: Pathophysiology, Imaging
Objective: This study aims to reveal the motor network effects of repetitive transcranial magnetic stimulation (rTMS) in Writer’s cramp (WC) subjects that correspond to behavioral efficacy. We hypothesized that clinical efficacy is associated with modulation of cortical and subcortical motor network areas.
Background: WC dystonia is an involuntary movement disorder with broadly distributed abnormalities in the brain’s motor network. Prior studies established the potential for rTMS at either premotor cortex (PMC) or primary somatosensory cortex (PSC) to modify symptoms. Clinical effects, however, have been modest with limited understanding of the neural mechanisms limiting improvements of this promising approach.
Method: In a double-blind, cross-over design, twelve WC subjects underwent weekly 10 Hz rTMS in one of three conditions (Sham-TMS, PSC-TMS, PMC-TMS) while engaged in a writing task to activate dystonic movements and measure writing fluency. Brain connectivity was evaluated using task-based functional magnetic resonance imaging (fMRI) after each TMS session.
Results: PSC-TMS, but not PMC-TMS, significantly improved writing dysfluency. Mechanistically, PSC-TMS significantly weakened functional connectivity (FC) between cortex and basal ganglia and strengthened nigral-cerebellar connectivity, relative to Sham, and in distinction from PMC-TMS. FC relationships strongly correlated with writing dysfluency and differed between Sham-TMS and PSC-TMS. Writing dysfluency was most strongly predicted by basal ganglia-cerebellar and cortico-subcortical region connectivity in Sham-TMS and cortico-cortical and cortico-cerebellar connectivity in PSC-TMS.
Conclusion: 10 Hz rTMS to PSC improves writing dysfluency in WC, causing broad redistribution of connectivity in the motor network. These findings offer mechanistic hypotheses to further improve therapeutic benefits of TMS for dystonia.
To cite this abstract in AMA style:
N. Bukhari-Parlakturk, P. Mulcahey, M. Lutz, R. Ghazi, Z. Huang, M. Dannhauer, P. Termsarasab, B. Scott, Z. Simsek, S. Groves, M. Lipp, M. Fei, T. Tran, E. Wood, L. Beynel, C. Petty, J. Voyvodic, L. Appelbaum, H. Al-Khalidi, S. Davis, A. Michael, A. Peterchev, N. Calakos. Transcranial magnetic stimulation target comparison identifies motor network reorganization associated with behavioral improvement in writer’s cramp dystonia [abstract]. Mov Disord. 2024; 39 (suppl 1). https://www.mdsabstracts.org/abstract/transcranial-magnetic-stimulation-target-comparison-identifies-motor-network-reorganization-associated-with-behavioral-improvement-in-writers-cramp-dystonia/. Accessed June 14, 2025.« Back to 2024 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/transcranial-magnetic-stimulation-target-comparison-identifies-motor-network-reorganization-associated-with-behavioral-improvement-in-writers-cramp-dystonia/