Mapping the role of vagus nerve stimulation in post-stroke arm motor recovery.

Objective: To map the scope, nature, and extent of evidence on using Vagus Nerve Stimulation (VNS) for post-stroke arm motor recovery in preclinical and clinical settings, identifying key findings, safety profiles, and evidence gaps to guide future research.

Data sources: Following the Arksey and O'Malley framework and PRISMA-ScR guidelines, we searched PubMed, Embase, Scopus, Cochrane Library, Web of Science, and Google Scholar for studies published up to March 2025. Studies evaluated invasive or transcutaneous auricular VNS (taVNS) for arm or forelimb motor recovery in adult stroke survivors or animal models.

Study selection: The titles and abstracts of selected studies were screened against the eligibility criteria using Covidence software to ensure rigor and transparency. Studies that met the inclusion criteria or required a full-text review were retained. Discrepancies were resolved through discussion or consultation with a third reviewer. A full-text review was done to arrive at a final list of studies.

Data extraction: Data were extracted on study characteristics, intervention protocols, motor outcomes, safety profiles, and evidence gaps.

Data synthesis: A scoping synthesis approach was employed, with scoping synthesis organized by preclinical and clinical findings.

Conclusions: VNS is a promising adjunct to task-specific rehabilitation, enhancing arm motor recovery with a favorable safety profile. taVNS offers a scalable, non-invasive alternative but requires further optimization. Future research should focus on diverse stroke populations, standardize protocols, and investigate synergistic combinations with other rehabilitative strategies to optimize functional outcomes.