The Effects of Electrical Stimulation of Lower Extremity Muscles on Balance in Stroke Patients: A Systematic Review of Literatures

Objective: Stroke is one of the main causes of disability and the second common cause of mortality in the world. Stroke causes relatively permanent motor defects, including balance disorder, and thus affects an individual's functional capacity and independence. Many clinical types of research have been conducted to evaluate the effect of functional electrical stimulation (FES) on balance in post-stroke patients. The objective of this study was to systematically review the effect of functional electrical stimulation (FES) on balance as compared to conventional therapy alone in post-stroke. Methods: The databases of Google Scholar, PubMed, Scopus, Science-Direct and ProQuest were searched using selected keywords. The randomized controlled trials were searched for published original articles before February 2019 in English language and included if they assessed the effect of FES on balance ability compared to conventional therapy alone in adult post-stroke. The Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality. Results: Nine papers were included in this review (median PEDro scale =7/11). The total number of participants in this review study was 255. The age of participants ranged from 20 to 80 years. Stroke patients were in chronic phase (n = 5) and in subacute phase (n = 4). various parameters, including the target muscles, the treatment time per session (20 min-2 h), number of treatment sessions (12-48) and FES frequency (25-40 Hz), were assessed. Among the studies, significant between-group improvement favoring FES in combination with conventional therapy was found on the Berg Balance Scale (n = 7) and Timed Up and Go Scale (n = 4) when compared to conventional therapy alone. There was no adverse effect reported by any studies. Conclusion: FES was reported to be more beneficial in balance improvement among stroke patients when combined with conventional balance therapy. The studies were limited by low-powered, small sample sizes ranging from 9 to 48, and lack of blinding, and reporting of missing data.