Transcutaneous spinal cord stimulation for stroke rehabilitation: a scoping review.
BACKGROUND Transcutaneous spinal cord stimulation (tSCS) is an emerging noninvasive neuromodulation approach for rehabilitation in individuals with stroke. Studies have suggested benefits, but evidence remains fragmented and methodologically heterogeneous. OBJECTIVE This scoping review maps and synthesizes current evidence on tSCS for stroke rehabilitation, focusing on study design, stimulation parameters, outcome measures, and reported effects. METHODS Following PRISMA-ScR guidelines, we systematically searched five databases (PubMed, Embase, Web of Science, CINAHL, and Google Scholar) from inception to December 2025. Two independent reviewers screened titles and abstracts, with a third resolving discrepancies. We extracted data on participant characteristics, stimulation parameters, outcome measures, and findings. RESULTS Thirteen studies met inclusion criteria, comprising five randomized and eight non-randomized designs, with sample sizes ranging from 2 to 21 participants. Most studies enrolled predominantly male individuals with chronic stroke. Four studies used multi-session protocols while nine single session protocols. Stimulation parameters varied widely amplitude (5-250 mA), frequency (15-100 Hz), carrier frequency (0-10 kHz), and pulse width (0.5-2 ms). Ten studies targeted lower-extremity function, two upper extremity functions, and one autonomic function. Multi-session trials pairing tSCS with task-specific training reported improvements in selected outcomes, though small sample sizes limit generalization. CONCLUSIONS tSCS remains an exploratory adjunctive intervention in stroke rehabilitation. Future research should prioritize adequately powered controlled trials with standardized stimulation protocols, stratification by stroke severity and chronicity, and long-term follow-up to establish clinical efficacy and optimal implementation in stroke rehabilitation.