Effect of transcutaneous auricular vagus nerve stimulation on post-stroke dysphagia

Background and purpose: It has been proved that electrical vagus nerve stimulation can promote the recovery of motor function after stroke. There were no trials on the use of transcutaneous auricular electrical vagus nerve stimulation (ta-VNS) in patients with dysphagia after acute stroke. Our aim was to confirm whether ta-VNS can promote the recovery of swallowing function in these acute stroke patients with dysphagia.

Methods: We conducted a sham-controlled, double-blinded, parallel pilot study in 40 acute stroke patients randomly assigned to receive ta-VNS or sham ta-VNS combined with conventional rehabilitation training. The intensity of ta-VNS treatment was adjusted according to the patient's tolerance, 30 min each time, twice a day, five times a week, with a total course of 3 weeks. In the sham group, the parameters were the same except energy output. Swallowing function was assessed with Modified Mann assessment of swallowing ability (MASA), functional communication measure swallowing test (FCM), and the Rosenbek leakage/aspiration scale (RAS) according to swallowing video fluoroscopic (SVF) before the intervention (baseline, T0), immediately after the intervention (T1) and 4 weeks after the intervention (T2).

Results: After treatment, ta-VNS group statistically and clinically had larger change of MASA, FCM, and RAS scores compared with control group (P < 0.05) and this improvement continued at least 4 weeks after the end of treatment. There were no serious adverse events occurred during the whole intervention.

Conclusion: The transcutaneous auricular electrical vagus nerve stimulation is effective as a novel and noninvasive treatment strategy for patients with dysphagia after acute stroke.

Trial registration: No: kelunshen No. 63 in 2020.