Non-invasive vagus nerve magnetic stimulation combined with rehabilitation training for vocal cord paralysis and dysphagia following brain injury: a prospective case series study

Background Vocal cord paralysis combined with dysphagia following brain injury is a severe complication associated with aspiration pneumonia, asphyxiation, and malnutrition, for which traditional rehabilitation yields limited efficacy. Non-invasive vagus nerve magnetic stimulation (nVNMS) is an emerging neuromodulation technology; however, systematic clinical studies addressing this specific dual-deficit population remain lacking. Methods A prospective case series study was conducted at Guangdong Sanjiu Brain Hospital (June 2024–May 2025), consecutively enrolling 38 inpatients with brain injury–related vocal cord paralysis and dysphagia. All patients received a 21-day combined protocol comprising left mastoid nVNMS (5 Hz, 20 min/session, once daily), low-frequency pulse electrical stimulation for swallowing (20 min/session, once daily), and manual swallowing training (30 min/session, once daily). Outcomes were assessed at baseline and post-treatment using the Standardized Swallowing Assessment (SSA), Food Intake Level Scale (FILS), Penetration-Aspiration Scale (PAS), and laryngoscopy, with adverse events recorded throughout. Results After treatment, SSA scores decreased from 36.92 ± 4.71 to 32.63 ± 7.10 ( p < 0.001, Cohen’s d = 0.72, large effect), FILS scores increased from 2 (2–2) to 3 (2–3) (p < 0.001, representing transition from total tube-feeding dependence to eligibility for supervised minimal oral intake), and PAS scores decreased from 6 (4–6) to 4 (4–4) ( p < 0.001, r = 0.64, large effect, representing restoration of functional airway protective response). The incidence of vocal cord paralysis decreased from 100 to 63.2% ( p < 0.001), tracheostomy cannula retention rate decreased from 55.3 to 26.3% ( p = 0.001), with 11 patients achieving decannulation and thereby regaining airway independence; nasogastric tube retention rate decreased from 100 to 68.4% ( p < 0.001), with 12 patients recovering oral feeding ability. No serious adverse events occurred during treatment. Conclusion As a preliminary case series without a control group, nVNMS combined with rehabilitation training may improve swallowing safety and vocal cord function and reduce airway management requirements in patients following brain injury, with favorable short-term safety. Owing to the lack of a control group, the specific effect of nVNMS and the impact of natural recovery cannot be differentiated; thus, multicenter randomized controlled trials are required for further validation.