Immediate and Long-Term Effects of Noninvasive Vagus Nerve Stimulation on Upper Extremity Function in Stroke Patients

Objective: Noninvasive vagus nerve stimulation (nVNS), as a new neuromodulation technique, has shown great potential in the field of stroke rehabilitation. The purpose of this study was to systematically evaluate the immediate and long-term effects of nVNS on upper limb function and its safety in stroke patients. Design: We systematically searched 8 databases, including PubMed, Web of Science, Embase, Cochrane Library, and CNKI, to screen randomized controlled trials (RCTs) evaluating the effects of nVNS on upper limb function in stroke patients. The time range is set from the establishment of each database to June 14, 2025. RevMan 5.3 and Stata 17.0 software were used for data analysis. Results: Ten RCTs involving 450 patients were included. The nVNS intervention can safely and effectively improve the upper limb motor function and activities of daily living in stroke patients. The effect was better when the duration of intervention was ≥4 weeks and the stimulation frequency was 25 Hz. The efficacy was maintained at 30 and 90 days after the intervention. Conclusion: The clinical benefit may be maximized when the duration of the intervention is not <4 weeks and the stimulation frequency is 25 Hz.