Implantable Vagus Nerve Stimulator–Paired Neurorehabilitation for Upper Limb Function After Ischemic Stroke: Evidence From a Systematic Review and Meta-Analysis With Best Practice Recommendations

BACKGROUND AND OBJECTIVES: Upper limb motor recovery is limited and affects functional outcomes in stroke survivors. Recent randomized controlled trials have assessed the role of combining vagus nerve stimulation with standard neurorehabilitation. The aim of this review was to evaluate the effectiveness of pairing implanted vagus nerve stimulation (I-VNS) with rehabilitation therapy in ischemic stroke patients and to provide a framework for its integration into standard clinical practice. METHODS: We searched PubMed, Scopus, CINAHL Plus, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews for articles published from inception to July 2024. Randomized controlled trials and follow-up studies assessing the efficacy and/or safety of I-VNS in stroke rehabilitation were included. The outcomes included upper limb motor function and adverse events related to intervention. The risk of bias was assessed using the Cochrane risk-of-bias tool, and a random-effects model was generated for the meta-analysis using the Meta package in R. RESULTS: The final analysis included 8 studies, with a cumulative sample size of n = 498 patients who underwent I-VNS-paired rehabilitation for upper extremity weakness in unilateral supratentorial stroke. The intervention group (I-VNS) included 245 patients (49.1%) whereas the control group had 252 patients (50.6%). The mean age was 59.0 ± 10.01 years in the intervention group and 61.0 ± 9.7 years in the control group. The intervention group included 155 male patients (63.2%), and the control group had 165 male patients (64.4%). The meta-analyses showed statistically significant improvement in upper limb motor function in the I-VNS-paired rehabilitation group with a mean difference of 2.73 (95% CI: 1.32-4.13; P = .04) in the Fugl-Meyer Assessment for Upper Extremity score. Only one study reported a serious adverse event. CONCLUSION: A systematic review and meta-analysis of the current literature provides high-level evidence that I-VNS-paired rehabilitation improves functional outcomes and has a favorable safety profile in patients with poststroke upper extremity weakness.