Objective: To study the effects of tDCS on motor activity of lower limb muscles and gait performance in chronic stroke patients.

Materials and Methods: Ten chronic stroke patients participated in a single-blind, crossover, and sham-controlled pilot study. Each patient participated in two stimulation conditions applied to the lower limb motor cortex area of affected hemisphere, i.e., anodal stimulation (2 mA, 10 minutes) and sham stimulation (2 mA, 30 seconds). The sequence of stimulation was randomly assigned. Wash-out period between stimulation is at least 48 hours. Root mean square [RMS] amplitude and median frequency [MF] of the vastus medialis oblique [VMO] and tibialis anterior [TA] muscles of the paretic limb and the Timed Up & Go test [TUG] were measured before and immediately after stimulation.

Results: The average RMS amplitude of the VMO muscle of the paretic limb increased by 13.6% and 7.7% after anodal tDCS and sham stimulation, consecutively. The average RMS amplitude of the TA muscle decreased by 2.3% and increased by 9.1% after tDCS and sham stimulation. The average MF of the VMO muscle of the paretic limb decreased by 1.9% and 2.9% after anodal tDCS and sham stimulation, consecutively. The average MF of the TA muscle decreased by 2.4% and increased by 2.9% after tDCS and sham stimulation. The TUG was decreased by 1.2% and increased by 1.7% after tDCS and sham stimulation, consecutively. RMS, MF, and TUG were not statistically different between tDCS and sham stimulation (ANCOVA test, p>0.05).

Conclusion: Single session of anodal tDCS at ipsilesional hemisphere could not enhance motor activity of lower limb muscles in chronic stroke patients.

Keywords: Transcranial direct current stimulation, Stroke, Rehabilitation, Motor cortex