Adjuvant effects of vagus nerve stimulation on post- stroke rehabilitation: a systematic review and meta- analysis

Comprehensive Summary

This study is a systematic review and meta-analysis to evaluate whether vagus nerve stimulation improves functional recovery after stroke beyond the current gold standard rehabilitation alone. The authors analyzed 18 randomized controlled trials with a cumulative sample size of 954 stroke patients, comparing invasive and non-invasive vagal nerve stimulation modalities, each combined with either conventional rehabilitation or sham therapy. Outcomes were pooled using random-effects models. Across studies, vagus nerve stimulation was associated with significant improvements in upper-extremity motor function, functional upper extremity use potential, swallowing function, wrist extensor muscle strength, motor evoked potential latency, and activities of daily living. In contrast, hand dexterity, spasticity, and quality-of-life measures showed no consistent benefit. Subgroup analyses suggested that invasive vagus stimulation and longer treatment durations (>6 weeks) may produce greater motor improvements, and overall safety profiles were comparable between nerve stimulation and control groups.

Outcomes and Implications

Stroke remains a leading cause of long-term disability, and this study analyzes effective adjunctive therapies to enhance neuroplastic recovery, the hard sciences of which are currently limited in the scientific literature. The findings support vagal nerve stimulation as a clinically relevant, generally safe adjunct to rehabilitation that may meaningfully improve motor recovery, swallowing, and functional independence in stroke populations. However, given study limitations such as small individual study sample sizes and heterogeneity across outcomes, further investigation is needed before widespread adoption of this technique in a gold-standard rehabilitation course. Additionally, this study provides little guidance on the optimal stimulation modality, dosing, and treatment duration for its proposed adjuvant therapy.