Comparison of the effects of and usability of active and active-assistive rehabilitation robots for the upper extremity function among patients with stroke: a single-blinded randomized controlled pilot study

Background Robotic rehabilitation of stroke survivors with upper extremity dysfunction yields different outcomes depending on the robot type. Considering that excessive dependence on assistive force provided by robots may interfere with the patient’s active learning and participation, we hypothesized that the use of an active-assistive robot does not lead to a more meaningful difference with respect to upper extremity rehabilitation than the use of an active robot. Accordingly, we aimed to evaluate the differences in the clinical and kinematic outcomes between active and active-assistive robotic rehabilitation among stroke survivors. Methods In this single-blinded randomized controlled trial, we assigned 20 stroke survivors with upper extremity dysfunction (Medical Research Council scale score, 3 or 4) to the active (ACT) and active-assistive (ACAS) robotic rehabilitation groups in a 1:1 ratio and administered 20 sessions of 30-minute robotic intervention (5 days/week, 4 weeks). The primary (Wolf Motor Function Test [WMFT]-score and -time: measures activity), and secondary (Fugl-Meyer Assessment [FMA] and Stroke Impact Scale [SIS] scores: measure impairment and participation, respectively; kinematic outcomes) outcome measures were determined at baseline, after 2 and 4 weeks of the intervention, and 4 weeks after the end of the intervention. Furthermore, we evaluated the usability of the robotic devices by conducting interviews with the patients, therapists, and physiatrists. Results In both the groups, the WMFT-score and -time improved over the course of the intervention. Time had a significant effect on the WMFT-score and -time, FMA-UE, FMA-prox, and SIS-strength; group × time interaction had a significant effect on SIS-function and SIS-social participation (all, p < 0.05). The ACT group showed better improvement in participation and smoothness than the ACAS group. In contrast, the ACAS group exhibited better improvement in mean speed. Conclusions There were no differences between the two groups regarding the impairment and activity domains. However, the ACT robots were more beneficial than ACAS robots regarding participation and smoothness. Considering the high cost and complexity of ACAS robots, ACT robots may be more suitable for robotic rehabilitation in stroke survivors who can perform voluntary movement. Trial registration: The trial was registered retrospectively on 14 March 2018 at ClinicalTrials.gov (NCT03465267).