Transcutaneous auricular vagus nerve stimulation for dysphagia in acute stroke: a randomized sham-controlled trial

BACKGROUND: Post-stroke dysphagia (PSD) is a frequent and debilitating complication that affects stroke patients and is strongly associated with relevant morbidity and increased mortality. Current PSD rehabilitation strategies are only partially effective, and fewer than 20% of patients return to their pre-stroke diet. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique capable of enhancing neuroplasticity through activation of brainstem vagal nuclei, including the nucleus tractus solitarius, which plays a central role in the swallowing pattern generator. Preliminary human and animal studies suggest that taVNS may augment motor recovery and exert neuroprotective effects in the acute stroke phase. This study investigated whether taVNS combined with swallowing rehabilitation improves PSD outcomes when administered within the first week after stroke. METHODS: This was a parallel-group, superiority, randomized, double-blind, sham-controlled trial including 30 acute stroke patients (ischemic or haemorrhagic) with dysphagia confirmed by fiberoptic endoscopic evaluation (FEES). Participants were randomized to real or sham taVNS delivered simultaneously with standardized swallowing therapy for three consecutive days. Swallowing function was assessed at baseline (T0), after the intervention (T1), and at 3 months (T2) using FEES-derived validated scales. Neurological disability (NIHSS, mRS), medical complications, and mortality were also recorded. Primary analysis used repeated-measures ANOVA. RESULTS: Compared to sham, the real taVNS group demonstrated greater improvements from T0 to T1 across all swallowing measures (FEDSS [p = 0.024], DOSS [p = 0.022], PAS [p = 0.018], P-score [p = 0.008], and FOIS [p = 0.021]), with effects persisting at T2 for FEDSS (p = 0.046). Length of stay in Stroke Unit was shorter in the real group (5.9 ± 2.8 vs 11.3 ± 8.7 days, p = 0.002). No serious adverse events occurred. CONCLUSIONS: Early taVNS, paired with swallowing rehabilitation, was associated with improvements in dysphagia recovery, in acute stroke. This short, safe intervention may accelerate functional improvement and could represents a promising adjunctive therapy for PSD. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT06827301.