Usability and effectiveness of a novel bilateral upper limb training device for stroke patients with hemiparesis: a pilot randomized controlled study

Rehabilitation for stroke patients with upper extremity (UE) dysfunction remains challenging in terms of promoting motor recovery and restoring functional independence. Device-assisted training has been introduced in clinical practice; however, its benefits still need to be evaluated, and there is a continued need for innovative solutions. In this study, we developed Synslai, a novel and non-powered mechanical UE rehabilitation device based on the principle of bilateral training (BT) that supports self-initiated UE training. It also facilitates patient autonomy and engagement in rehabilitation. This study assessed its effectiveness and usability in stroke patients. Patients with stroke onset within 12 months in this open-label randomized controlled trial, conducted in a single hospital, were randomized and allocated to an experimental group (EG), which received combined Synslai and conventional occupational therapy (OT), or a control group (CG), which received UE functional training and conventional OT. Both groups received equivalent training dosages: 90-minute sessions, five times per week, yielding a total of 10–15 sessions over 3 weeks. The primary outcome was the Fugl-Meyer Assessment for Upper Extremity (FMA-UE), and the secondary outcomes were the Brunnstrom stage and Modified Ashworth Scale. The System Usability Scale (SUS) and satisfaction questionnaires were administered to evaluate device usability and user satisfaction. Assessments were performed before and after the training. A total of 54 participants completed the whole trial. The FMA-UE scores improved in both groups; however, the improvement did not differ between the two groups. Notably, a significant gain in the coordination/speed was observed only in the EG (p = 0.005). The SUS and satisfaction scores met the usability and acceptability standards. The present study showed that as a novel device that applies BT theory, the Synslai demonstrated favorable usability and was non-inferior to control therapy. Preliminary results suggest it might be more effective in improving spatial coordination. Further studies with larger sample sizes are needed to characterize its clinical efficacy and integration with conventional rehabilitation approaches. Trial Registration This study was registered in ClinicalTrials.gov, NCT06956677, on May 1, 2025. (https://clinicaltrials.gov/study/NCT06956677).