Effects of transcranial direct current stimulation on walking ability after stroke: A systematic review and meta-analysis

Background: As a promising technique, transcranial direct current stimulation (tDCS) has gained so much attention in its potential effects on functional recovery of lower limb following stroke. However, individual studies have yielded inconsistent or conflicting results. Objective: To investigate the efficacy and safety of tDCS for the functional recovery of lower limb following stroke reported in the randomized controlled trials by using a meta-analysis. Methods: MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, CENTRAL, and Physiotherapy Evidence Database was comprehensively searched for randomized controlled trials published until April 2017 that investigated the effects of tDCS on lower limb function. Main outcomes included walking speed, walking endurance, mobility, balance function, muscle strength of lower limb and adverse events. Results: A total of 10 trials (n = 194) met the inclusion criteria. Meta-analysis demonstrated a significant effect of tDCS on mobility (SMD 0.44, 95% CI: 0.01 to 0.87, P = 0.04) and muscle strength of lower limb (SMD 1.54, 95% CI: 0.29 to 2.78, P = 0.02). No significant effects were found in walking speed (SMD 0.39, 95% CI: -0.06 to 0.85, P = 0.09), walking endurance (SMD 0.28, 95% CI: -0.28 to 0.84, P = 0.33) and balance function (SMD 0.44, 95% CI: -0.06 to 0.94, P = 0.08). Conclusion: tDCS might have beneficial effects on improving mobility and muscle strength of lower limb among individuals with stroke. Future studies with larger sample sizes and an adequate follow-up period are needed.