Effect of Combined Vagus Nerve Stimulation on Recovery of Upper Extremity Function in Patients with Stroke: A Systematic Review and Meta-Analysis

Abstract

ObjectiveTo evaluate the effectiveness of vagus nerve stimulation (VNS) combined with rehabilitation therapies in restoring upper extremity (UE) function following stroke. Data Sources A search was implemented in key databases along with hand searches of relevant papers and performed on 31 July 2021. Materials and MethodsOnly randomized controlled trials (RCTs) assessing the effect of VNS focusing on UE dysfunction in patients post-stroke were identified in this systematic review. Data were extracted independently by two authors. The study was conducted by the Preferred Reporting Items for Meta-Analyses (PRISMA) guidelines. Meta-analyses were performed when deemed feasible. ResultsFive RCTs involving 178 patients (VNS/C 87/91) were included. The primary outcome was the function assessment by upper UE Fugl-Meyer assessment (FMA-U). As secondary outcomes, strength was assessed with the Wolf motor function test (WMFT), the Stroke Impact Scale (SIS) and the Motor Activity Log (MAL). Meta-analysis showed a significant immediate favoring VNS-based rehabilitation (five studies) for improving upper extremity function after stroke (mean difference [MD] 3.31; 95% confidence interval [CI], 2.33–4.29; p < 0.0001,fixed-effects model), along the lines of the long-term effect (three studies) (MD = 3.13; 95% CI, 1.47––4.79; p < 0.0001,fixed-effects model). No effect was observed when compared with control groups in adverse outcomes (Risk Ratio [RR] 1.61; 95% CI, 0.65–3.99; P = 0.30). ConclusionsVNS combined with rehabilitation training may be considered as a promising intervention in UE recovery in stroke patients.