Transcutaneous auricular vagus nerve stimulation significantly improves swallowing function in post-stroke dysphagia

Patients with post-stroke dysphagia (PSD) often experience severe swallowing difficulties, leading to aspiration pneumonia and malnutrition. Conventional swallowing rehabilitation offers limited efficacy for moderate-to-severe cases, particularly when neuromuscular activation is impaired. Transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive neuromodulatory technique, has emerged as a promising adjunct to enhance recovery by potentially modulating neural circuits involved in swallowing and reducing neuroinflammation.

This randomized controlled study enrolled 96 patients with post-stroke dysphagia, assigning them to either a control group (conventional swallowing rehabilitation) or a taVNS group (conventional rehabilitation + taVNS). The intervention lasted for 4 weeks. Primary endpoints included clinical swallowing outcomes (FOIS, SSA, PAS), swallowing-related surface electromyography (sEMG for Aemg, Iemg, reverse activation proportion, EMG latency), and serum biomarkers (BDNF, GFAP, IL-6). A total of 86 patients completed the study.

Both groups showed improved swallowing function, but the taVNS group exhibited significantly greater improvements across key clinical measures. FOIS scores improved more in the taVNS group (p < 0.001), as did SSA (p < 0.001) and PAS (p = 0.001). Neuromuscular activation also saw greater gains: taVNS led to larger increases in Aemg and Iemg, greater reductions in reverse activation proportion, and shorter EMG latency (all p < 0.05). Serum BDNF levels increased more prominently in the taVNS group, while GFAP and IL-6 levels showed significantly greater reductions (all p < 0.01).