Effects of Transcranial Direct Current Stimulation Combined With Mirror Therapy on Sensorimotor and Daily Functions in Patients With Stroke: A Sham-Controlled Case Series

Background and objectives: Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation for changing the damaged cortical excitability of stroke patients. It is a promising therapeutic technique in neurorehabilitation. Mirror therapy (MT) has been effective for improving sensorimotor functions of the upper extremity in stroke rehabilitation. To verify whether tDCS may be combined with MT for augmented treatment effects, this study was designed to investigate the effects of hybridizing tDCS with MT in patients with stoke. Methods: A randomized, double-blinded and sham-controlled study was conducted. Ten participants with chronic stroke were randomly assigned to receive tDCS combined sequentially with MT, or sham-tDCS combined with MT. All participants in the two groups received the intervention for 90-min five times a week for 4 weeks. Fugl-Meyer Assessment (FMA), revised Nottingham Sensory Assessment (RNSA), and Motor Activity Log (MAL) were administrated as primary outcomes, moreover; Wolf Motor Function Test (WMFT), Modified Ashworth Scale (MAS), Grip and Pinch Strength, kinematic assessment and actigraphy were secondary outcomes at pre- and post-treatment. Moreover, tDCS adverse effects questionnaire was applied in the study for monitoring the adverse effects. Results: For primary outcomes, tDCS + MT group had significant changes and large effect on the distal subscale of FMA (P = .048, r = .577); and the quality of movement subscale (P = .028, r = .596) and the amount of use subscale of MAL (P = .048, r = .562) for between-group comparisons. Sham-tDCS + MT group compared to another group were statistically different on the proximal subscale of FMA (P = .016, r = .681). Although there were few statically significant findings on secondary outcomes in both groups, MT+ tDCS group compared to Sham-tDCS + MT group may have trends of greater changes on lateral pinch strength, angular change of kinematic assessment; and caloric consumption and activity counts for actigraphy. Sham-tDCS + MT group showed a superior trend in tactile sensation and sterognosis of RNSA, the proximal subscale of MAS, and the time subscale of WMFT. Conclusion: The research supports the positive effects of tDCS combined with MT on motor and daily functions after stroke. With the case series designed in the study, the conclusion should be carefully inferred. Further studies with more sample size or long-term follow-up are needed to examine the present findings.