Repetitive Transcranial Magnetic Stimulation on individualized spots based on task fMRI improves swallowing function in post-stroke dysphagia.

Background: Functional magnetic resonance imaging (fMRI) has not previously been used to localize the swallowing functional area in repetitive transcranial magnetic stimulation (rTMS) treatment for post-stroke dysphagia; Traditionally, the target area for rTMS is the hotspot, which is defined as the specific region of the brain identified as the optimal location for transcranial magnetic stimulation (TMS). This study aims to compare the network differences between the TMS hotspot and the saliva swallowing fMRI activation to determine the better rTMS treatment site and investigate changes in functional connectivity related to post-stroke dysphagia using resting-state fMRI.

Methods: Using an information-based approach, we conducted a single case study to explore neural functional connectivity in a patient with post-stroke dysphagia before, immediately after rTMS, and four weeks after rTMS intervention. 20 healthy participants underwent fMRI and TMS hotspot localization as a control group. Neural network alterations were assessed , and functional connections related to post-stroke dysphagia were examined using resting-state fMRI.

Results: Compared to the TMS-induced hotspots, the fMRI activation peaks were located significantly more posteriorly and exhibited stronger functional connectivity with bilateral postcentral gyri. Following rTMS treatment, this patient developed functional connection between the brainstem and the bilateral insula, caudate, anterior cingulate cortex, and cerebellum.

Conclusion: The saliva swallowing fMRI activation peaks show more intense functional connectivity with bilateral postcentral gyri compared to the TMS hotspots. Activation peak-guided rTMS treatment improves swallowing function in post-stroke dysphagia. This study proposes a novel and potentially more efficacious therapeutic target for rTMS, expanding its therapeutic options for treating post-stroke dysphagia.