This clinical trial aims to investigate the mechanisms of brain reorganization underlying motor recovery following end-effector (EE) and exoskeleton (Exo) robot-assisted hand training in individuals with stroke. Using functional near-infrared spectroscopy (fNIRS), the study will (1) investigate brain activation patterns during EE and Exo robot-assisted hand movements in healthy adults and individuals with stroke and (2) examine longitudinal changes in brain activation and motor recovery over a 6-week intervention.

For Part 1, a cross-sectional observational study will be conducted to examine brain activation using fNIRS while participants perform EE and Exo robot-assisted movements. Healthy adults and individuals with stroke will each perform one session of each type of robot-assisted movement.

For Part 2, an evaluator-blinded randomized controlled design will be used. Participants will be stratified based on the level of motor impairment and the side of the brain lesion and then randomly assigned to either the EE or Exo robot-assisted training group. Both groups will receive training 3 times per week, with each session lasting 60 minutes, for a total of 6 weeks. Each session will include 40 minutes of robot-assisted therapy and 20 minutes of functional training.

Outcome assessments will be conducted at four time points: prior to the intervention (baseline), mid-intervention (during weeks 3-4 of the intervention), immediately after the intervention, and at the 3-month post-trial follow-up. These assessments will be used to evaluate motor recovery and longitudinal changes in brain function.

Stroke participants

Inclusion Criteria:

• unilateral stroke onset ≥ 3 months
• Fugl-Meyer Assessment for Upper Extremity (FMA-UE) score between 18 to 56 - modified Ashworth scale ≤ 3 in proximal joints and modified Ashworth scale ≤ 2 in distal joints
• able to follow 2-step instructions
• without excessive spasticity in any of the UE joints.

Exclusion Criteria:

• orthopedic conditions affecting the arm/hand or other neurological conditions
• severe pain that prevents movement in the affected arm and hand
• implanted cardiac pacemakers and cardioverter-defibrillators
• osteoporosis, fracture, or severe ataxia
• unstable medical status
• participating in other rehabilitation or drug studies simultaneously
• receiving Botulinum toxin injections within 3 months

Healthy participants

• have no neurological conditions
• have no musculoskeletal disorders affecting the UE