I. Introduction
Stroke is the second most fatal disease with a higher disability rate in the world. It brings great mental stress and affects the normal work and life of patients and their families [1], [2]. Transcranial direct current stimulation (tDCS) is an emerging and noninvasive neuromodulation technology which has been considered a very promising method in the field of neurorehabilitation [3]. Due to the superiority of high safety, strong portability, and easy operation [4], tDCS has been used in the study of motor nerve damage diseases such as stroke; however, its effect is not confirmed at present. Some studies suggested that tDCS had a positive effect on stroke. For example, Boggio et al. [5] found that tDCS could help improve lower limb motor function after Jebsen–Taylor Hand Function Test. Pavlova et al. [6] also found that tDCS was beneficial to the recovery of motor function after stroke in the variance analysis of repeated measurements between tDCS group and sham group. However, in Mazzoleni’s et al. [7] research, there was no significant difference between tDCS group and sham group after the same study. It was not found either by Edwards et al. [8] that tDCS had more advantages for rehabilitation training. It is of great clinical value to clarify the effect of tDCS on stroke.