Bi-cephalic transcranial direct current stimulation combined with functional electrical stimulation for upper-limb stroke rehabilitation: a double-blind randomized controlled trial

Background: Stroke survivors often present poor upper-limb (UL) motor performance and reduced movement quality during reaching tasks. Transcranial direct current stimulation (tDCS) and functional electrical stimulation (FES) are widely used strategies for stroke rehabilitation. However, the effects of combining these two therapies to rehabilitate individuals with moderate and severe impairment after stroke are still unknown. Objective: Our primary aim was to evaluate the effects of concurrent bi-cephalic tDCS and FES on UL kinematic motor performance and movement quality of chronic post-stroke subjects with moderate and severe compromise. Our secondary aim was to verify the effects of combining these therapies on handgrip force and UL motor impairment. Methods: We randomized 30 individuals with moderate and severe chronic hemiparesis after stroke into tDCS plus FES (n = 15) and sham tDCS plus FES (n = 15) groups. Participants were treated 5 times a week for 2 weeks. Kinematic motor performance (movement cycle time, velocity profile) and movement quality (smoothness, trunk contribution, joint angles) were assessed during an UL reach-to-target task.Handgrip force and motor impairment were also recorded before and after the intervention. Results: Participants allocated to the tDCS plus FES group improved movement cycle time (P = 0.039), mean reaching velocity (P = 0.022) and handgrip force (P = 0.034). Both groups improved the mean returning phase velocity (P = 0.018), trunk contribution (P = 0.022), movement smoothness (P = 0.001) and UL motor impairment (P = 0.002). Conclusions: Concurrent bi-cephalic tDCS and FES slightly improved reaching motor performance and handgrip force of chronic post-stroke individuals with moderate and severe UL impairment. Trial registration: ClinicalTrials.gov (NCT02818608).