The effects of combining anodal transcranial direct current stimulation with robot-assisted gait training on lower limb motor function and the motor cortex regulation of stroke patients

Abstract

BACKGROUND: The therapeutic effect and underlying mechanism of combining transcranial direct current stimulation (tDCS) with robot-assisted gait training (RAGT) for stroke patients remain unclear. METHODS: The goal of this study is to examine whether anodal tDCS can augment the beneficial effects of RAGT on motor function of the lower limbs in stroke survivors. Furthermore, the study aims to explore the brain motor function network underlying regulation mechanism of this integrated therapeutic approach.The patients were randomly assigned to two groups: the anode tDCS + RAGT group (n = 22) and the RAGT group (n = 21). In the experimental group, patients underwent a 20-minute session of anodal tDCS followed by a 20-minute RAGT session. Conversely, the control group patients only received 20 min of RAGT. These sessions were conducted 5 days a week for a duration of 4 weeks. Hemoglobin alterations in the primary motor cortex (M1) and pre-motor cortex/supplementary motor cortex area (PMC/SMA) of patients at rest were measured using Functional Near Infrared Spectroscopy (fNIRS). Additionally, the Fugl-Meyer Lower Extremity Assessment (FMA-LE) was utilized to evaluate the functionality of the lower extremities. RESULTS: A total of 38 stroke patients successfully completed the study. Significant improvements were observed in the FMA-LE scores of both groups following treatment. Notably, the anode tDCS + RAGT group demonstrated a remarkable enhancement in FMA-LE compared to the control group. Furthermore, the combination of anodal tDCS + RAGT strengthened the functional connectivity between LM1-RPMC/SMA. CONCLUSIONS: The combination of anodal tDCS and RAGT can enhance lower limb motor function in stroke patients, while also modulating the connectivity within the motor network. Additionally, the elevation of functional connectivity between the bilateral cerebral hemispheres, quantifiable through fNIRS, could potentially serve as a valuable biomarker in stroke patients. TRIAL REGISTRATION: This study has been registered in the Chinese Clinical Trial Registry (no. ChiCTR2400088222). This article has been registered on August 13th, 2024, and it was registered retrospectively.