Effects of two different protocols of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic supratentorial stroke: A single blind, randomized controlled trial

Background: The neural organization of locomotion involves motor patterns generated by spinal interneuronal networks and supraspinal structures, which are approachable by noninvasive stimulation techniques. Recent evidences supported the hypothesis that transcranial direct current stimulation (combined with transcutaneous spinal direct current stimulation) may actually enhance the effects of robot-assisted gait training in chronic stroke patients. The cerebellum has many connections to interact with neocortical areas and may provide some peculiar plasticity mechanisms. So, it has been proposed as "non-lesioned entry" to the motor or cognitive system for the application of noninvasive stimulation techniques in patients with supratentorial stroke. Objective: To compare the effects of two different protocols of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robotic gait training in patients with chronic supratentorial stroke. Methods: Forty patients with chronic supratentorial stroke were randomly assigned into two groups. All patients received ten, 20-minute robotic gait training sessions, five days a week, for two consecutive weeks. Group 1 underwent cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation in combination with robotic training. Group 2 underwent cathodal transcranial direct current stimulation over the ipsilesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation in combination with robotic training The primary outcome was the 6-minute walk test performed before, after, and at follow-up at 2 and 4 weeks post-treatment. Results: No significant difference in the 6-minute walk test between groups was found at the first post-treatment evaluation (P=0.976), as well as at the 2-week (P= 0.178) and the 4-week (P= 0.069) follow-up evaluations. Both groups showed significant within-group improvements in the 6-minute walk test at all time points. Conclusions: Our findings support the hypothesis that cathodal transcranial direct current stimulation over the contralesional or ipsilesional cerebellar hemisphere in combination with cathodal transcutaneous spinal direct current stimulation may lead to similar effects on robotic gait training in chronic supratentorial stroke patients.