Extending Reach: Efficacy of Hybrid Robotic-functional Electrical Stimulation Training for Post-stroke Upper Extremity Rehabilitation

Background Impaired upper extremity (UE) function is a major contributor to disability after stroke. Combining robotic devices with functional electrical stimulation (FES) has emerged as a promising hybrid approach to enhance post stroke UE function. Objective To assess the efficacy of robotic training with the REACH + multi-muscle FES device compared to the REACH device alone on UE function in individuals with chronic stroke. Methods This was a pilot non-blinded randomized control trial. Twenty individuals with chronic stroke were randomized to hybrid REACH + FES (n = 10) or REACH alone training (n = 10). All participants utilized the REACH device for training, which consisted of point-to-point reaching movements in response to a visually evoked task. The REACH + FES group additionally received multi-muscle FES during the REACH device training. Training consisted of 45-minute sessions, 3 times/week for six weeks, totaling 18 sessions. The primary outcomes were Upper Extremity Fugl Meyer Assessment (UE-FMA) and Action Research Arm Test (ARAT). Secondary outcomes included Reaching Performance Scale for Stroke (RPSS), Modified Ashworth Scale (MAS) and kinematic outcomes from the Kinereach/TrakStar virtual reality system. Results Both groups demonstrated improvements in clinical and kinematic outcomes post-training; but the REACH + FES group showed superior improvements in UE impairments (UE-FMA: p < 0.025, Far component of RPSS: p < 0.05, MAS: p < 0.05) and function (ARAT: p < 0.025). Additionally, REACH + FES alone exhibited improvements in unconstrained reaching, including distance (midline, contralateral and ipsilateral directions; p < 0.05) and contralateral linearity(p < 0.05). Conclusion There is preliminary support for the use of an end-effector, uniaxial robotic device integrated with multi-muscle FES to maximize UE functional improvement in individuals with chronic stroke in a clinically meaningful way. Clinical Trial Registration: NCT05854485.