Vagus nerve stimulation for upper limb motor impairment after ischemic stroke: A meta-analysis

Upper limb motor impairment is a common complication following stroke. Although few treatments are used to enhance motor function, still approximately 60% of survivors are left with upper limb motor impairment. Several studies have investigated vagus nerve stimulation (VNS) as a potential technique for upper limb function. However, the efficacy and safety of VNS on upper limb motor function after ischemic stroke have not been systematically evaluated. Therefore, a meta-analysis based on randomized controlled trial will be conducted to determine the efficacy and safety of VNS on upper limb motor function after ischemic stroke.

We searched PUBMED, MEDLINE, EMBASE, Cochrane Library, Web of Science, China National Knowledge Infrastructure Library (CNKI), and Wan Fang Database until April 1, 2021.

Six studies consisting of 234 patients were included in the analysis. Compared with control group, VNS improved upper limb function via Fugl-Meyer Assessment-Upper Extremity (mean difference = 3.26, 95% confidence interval [CI] [2.79, 3.74], P < .00001) and Functional Independence Measurement (mean difference = 6.59, 95%CI [5.77, 7.41], P < .00001), but showed no significant change on Wolf motor function test (standardized mean difference = 0.31, 95%CI [-0.15, 0.77], P = .19). The number of adverse events were not significantly different between the studied groups (risk ratio = 1.05, 95%CI [0.85, 1.31], P = .64).

VNS resulted in improvement of motor function in patients after ischemic stroke, especially in the sub-chronic stage. Moreover, compared with implanted VNS, transcutaneous VNS exhibited greater efficacy in poststroke patients. Based on this meta-analysis, VNS could be a feasible and safe therapy for upper limb motor impairment.