Transcranial direct current stimulation enhances propulsion during walking

Transcranial direct current stimulation (tDCS) has been shown to improve force generation and control in single leg joints in healthy subjects and stroke survivors. However, it is unknown whether these effects also result in improved force production and coordination during walking. Here we investigated the effect of tDCS using different electrode configurations on the coordinated motor output during walking. In a randomized double-blinded crossover design, 10 healthy subjects walked on an instrumented split-belt treadmill before and after 10 minutes of either uni-hemispheric (standard configuration), dual-hemispheric (one electrode over each hemisphere) or sham primary motor cortex (M1) tDCS. We found that tDCS enhanced the coordinated output during walking as reflected in an increased propulsive impulse. Although increases were observed in both legs only the increase in the leg contralateral to the hemisphere receiving anodal stimulation was significant. These results show that tDCS can improve force generation and coordination during walking. Future studies need to investigate whether tDCS can improve the coordinated output of the paretic leg of stroke survivors and in doing so its contribution to propulsion during walking.