Effect of Simultaneous High-definition Transcranial Direct Current Stimulation and Robot-assisted Gait Training on Gait Function in Chronic Stroke Patients

Abstract Background Robot-assisted gait training (RAGT) is used for rehabilitation after stroke, but not all chronic stroke patients achieve satisfactory improvement in physical ability. The purpose of this study was to investigate whether the effects of RAGT on gait and physical function in chronic stroke patients could be enhanced by simultaneously applying high-definition transcranial direct current stimulation (HD-tDCS). Methods Twenty-four chronic hemiplegic stroke patients (15 males; mean age 60.5 ± 13.9 years) participated in this study. The subjects were randomly allocated to either the RAGT with real HD-tDCS group (RAGT \(\stackrel{-}{\text{c}}\) rHD-tDCS) or the RAGT with sham HD-tDCS group (RAGT \(\stackrel{-}{\text{c}}\) sHD-tDCS). Each group completed 10 sessions over four consecutive weeks. Gait and physical function were measured by the 10 Meter Walk Test (10MWT), Timed Up and Go (TUG), Functional Ambulation Category (FAC), Functional Reach Test (FRT), Berg Balance Scale (BBS), Dynamic Gait Index (DGI), Fugl-Meyer Assessment (FMA), and the Korean version of the Modified Barthel Index (K-MBI). Assessments were performed before intervention (Pre), immediately after intervention (Post), and at follow-up (F/U) one month after the intervention. Results The RAGT \(\stackrel{-}{\text{c}}\) rHD-tDCS group showed statistically significant improvements in 10MWT, TUG, FRT, and BBS at Post and F/U compared to Pre (P < 0.05). The RAGT \(\stackrel{-}{\text{c}}\) rHD-tDCS group also improved significantly in the DGI and FMA at Post compared with Pre (P < 0.05). The RAGT \(\stackrel{-}{\text{c}}\) sHD-tDCS did not show significant improvement at Post or F/U compared to Pre. Repeated measures analysis of variance revealed significant time × group interactions in the FMA and the K-MBI (P < 0.05), indicating that the RAGT \(\stackrel{-}{\text{c}}\) rHD-tDCS group experienced greater improvements in motor and activities of daily living functions compared with the RAGT \(\stackrel{-}{\text{c}}\) sHD-tDCS group. Conclusion These results demonstrate that simultaneous application of HD-tDCS during RAGT produces positive effects on gait and physical function in chronic stroke patients. Combining RAGT with HD-tDCS ensured long-term training effects for up to one month. HD-tDCS can be suggested as a complementary tool for enhancing robotic gait rehabilitation therapy in chronic stroke patients after a larger confirmatory study to verify these effects. Trial registration: Clinical trials registration information: ClinicalTrials.gov Identifier: NCT04985864 (07/30/2021).