Walking in multiple sclerosis improves with tDCS: a randomized, double-blind, sham-controlled study

Objective: To evaluate whether multiple sessions of transcranial direct current stimulation (tDCS) applied to the primary motor (M1) cortex paired with aerobic exercise can improve walking functions in multiple sclerosis (MS). Methods: MS participants were recruited for a double-blind, parallel-arm, randomized, sham-controlled trial and assigned to 10 sessions (5 d/wk for 2 weeks) of either active or sham tDCS paired with unloaded cycling for 20 minutes. Stimulation was administered over the left M1 cortex (2.5 mA; anode over C3/cathode over FP2). Gait spatiotemporal parameters were assessed using a wearable inertial sensor (10-meter and 2-minute walking tests). Measurements were collected at baseline, end of tDCS intervention, and 4-week postintervention to test for duration of any benefits. Results: A total of 15 participants completed the study, nine in the active and six in the sham condition. The active and sham groups were matched according to gender (50% vs. 40% female), neurologic disability (median EDSS 5.5 vs. 5), and age (mean 52.1 +/- 12.9 vs. 53.7 +/- 9.8 years). The active group had a significantly greater increase in gait speed (0.87 vs. 1.20 m/s,p < 0.001) and distance covered during the 2-minute walking test (118.53 vs. 133.06 m,p < 0.001) at intervention end compared to baseline. At 4-week follow-up, these improvements were maintained (baseline vs. follow-up: gait speed 0.87 vs. 1.18 m/s,p < 0.001; distance traveled 118.53 vs. 143.82 m,p < 0.001). Interpretation: Multiple sessions of tDCS paired with aerobic exercise lead to cumulative and persisting improvements in walking and endurance in patients with MS.