Identifying candidates for torque-assisted exoskeleton for gait assistance after stroke: a pre-specified subgroup analysis

Abstract

BACKGROUND: Wearable robots show promise for gait assistance in stroke patients, yet the clinical characteristics predicting a positive ambulatory response to exoskeletal assistance remain unclear.<br /> AIM: To identify appropriate candidates for torque-assisted exoskeletal wearable robots in stroke patients.<br /> DESIGN: A subgroup analysis using data from an international, multicenter, randomised controlled trial.<br /> SETTING: Inpatient.<br /> POPULATION: Fifty-five early subacute stroke patients who completed four weeks of robot-assisted gait training (RAGT) with the wearable exoskeletal robot (ANGEL LEGS M20, Angel Robotics Co., Ltd.).<br /> METHODS: Immediately after RAGT for the four weeks, ambulatory function with the exoskeleton on and off was evaluated using the 10-Meter Walk Test (10MWT), 6-Minute Walk Test (6MWT), and Physiological Cost Index (PCI). At the same time, additional assessments included the Functional Ambulatory Category (FAC), Fugl-Meyer Assessment-Lower Extremity, Motricity Index-Lower Limb, Trunk Control Test, and Berg Balance Score. Participants were classified as good-responder, no-responder, or negative-responder groups based on changes in walking performance with exoskeletal assistance. Univariate and multivariate ordinal logistic regression analyses identified factors associated with responsiveness.<br /> RESULTS: In the good-responder group, 10MWT, 6MWT and PCI showed significant improvements in the robot-on state compared with the robot-off state, respectively (P<0.05). Good responders had significantly lower baseline ambulatory, balance, and lower limb motor function compared to negative-responders (P<0.05). Multivariate analysis identified lower FAC as the only independent predictor of positive response to exoskeletal assistance (P<0.05).<br /> CONCLUSIONS: Torque-assisted exoskeletal wearable robots may improve ambulatory function in stroke patients with low ambulatory function.<br /> CLINICAL REHABILITATION IMPACT: To achieve meaningful effects through exoskeleton robots, patient selection must be adjusted according to clinical needs.