Efficacy and Mechanism of Transcutaneous Auricular Vagus Nerve Stimulation in Patients With Poststroke Dysphagia: Protocol for a Randomized, Sham-Controlled Clinical Trial

Background: Dysphagia is a common complication following stroke. While current management strategies for poststroke dysphagia (PSD) range from nutritional support to neurostimulation techniques, an optimal treatment regimen remains elusive. As a promising noninvasive neuromodulation approach, transcutaneous auricular vagus nerve stimulation (taVNS) requires further validation in rigorously designed trials to establish robust evidence of its efficacy and mechanisms of action. Objective: This study aims to validate the efficacy of taVNS in treating PSD and to elucidate its underlying mechanisms, thereby supporting the development of a novel, noninvasive therapeutic strategy for improving swallowing function in stroke survivors. Methods: This study will use a prospective, randomized, double-blind, controlled trial design. A total of 40 patients with PSD will be enrolled and randomly allocated to either a taVNS group or a sham taVNS group. Both groups will receive conventional swallowing rehabilitation therapy as the baseline intervention. The taVNS group will receive bilateral electrical stimulation at the cymba conchae and cavum conchae of the auricle. These sites correspond to the "Heart" and "Kidney" auricular acupoints, selected in accordance with traditional Chinese medicine theory. In contrast, the sham taVNS group will receive stimulation at regions of the auricle not innervated by the vagus nerve. The primary outcome measure will be the Penetration-Aspiration Scale score. Secondary outcomes will include the Yale Pharyngeal Residue Severity Rating Scale, hyoid bone displacement and hyoid-thyroid approximation distance assessed via B-mode ultrasonography, and motor-evoked potentials of the suprahyoid muscles elicited by transcranial magnetic stimulation. All outcome measures will be evaluated at baseline and after the 2-week intervention period. Results: This paper describes the protocol for a study evaluating the efficacy and mechanisms of taVNS in patients with PSD. The study was funded in January 2025. Participant recruitment began in March 2025 and is projected to conclude by October 2026. Data collection began in March 2025 and is projected to be completed by October 2026. Primary study results are expected to be submitted for publication in winter 2026. Conclusions: This study aims to validate the efficacy of taVNS in treating PSD and to elucidate its underlying mechanisms, thereby supporting the development of a novel, noninvasive therapeutic strategy for improving swallowing function in stroke survivors.