ZEPU-AI1 Gait Robot Training Study (ZEPUAI1RCT)

This is a single-site, pilot, randomized controlled trial evaluating the feasibility, safety, and preliminary efficacy of the ZEPU-AI1 Gait Training and Evaluation System, a computer-controlled robotic rehabilitation device, in adults with lower-limb motor dysfunction. The trial will be conducted at the Robotic Rehabilitation Centre, Department of Physical Medicine and Rehabilitation, Bangladesh Medical University (BMU), Dhaka, Bangladesh.

Thirty-two participants aged 19-60 years with lower-limb motor dysfunction secondary to stroke (2-24 months post-onset), incomplete spinal cord injury (ASIA C or D, neurological level T12 or below), or persistent gait impairment following orthopedic surgery (>3 months post-surgery) will be enrolled after screening against detailed inclusion/exclusion criteria (including device-specific anthropometric limits, medical stability, and absence of severe spasticity, unstable fractures, or cardiac contraindications). Participants will be randomized into two parallel arms:

Intervention Arm (n=16): ZEPU-AI1 robot-assisted gait training combined with standard-of-care rehabilitation.

Control Arm (n=16): Standard-of-care rehabilitation alone.

The ZEPU-AI1 is a bilateral robotic exoskeleton system integrating a gait control unit (programmable hip range 30°-50°, knee range 50°-80°), a dynamic body-weight support mechanism (0-80 kg unloading), a motorized treadmill (0.1-3.5 km/h), and dedicated software providing real-time gait monitoring, spasticity detection, and automatic safety shutoff. Intervention-arm participants will undergo supervised training three times weekly for 12 weeks (36 sessions total), each session approximately 45 minutes, comprising warm-up, device donning, structured standing/gait training (sit-to-stand, in-place stepping, overground walking, turning), and cool-down, with progressive adjustment of speed, body-weight support, and duration based on tolerance.

Primary outcomes are feasibility (recruitment, session adherence, device set-up/donning time, therapist competency time) and safety (incidence of device-related adverse events and serious adverse events, tolerability, dropout rate), assessed continuously throughout the intervention and at two-week intervals.

Secondary outcomes assess efficacy using standardized, validated instruments administered at baseline and two-week intervals over the 12-week period: 6-Minute Walk Test, Medical Research Council (MRC) Muscle Strength Scale, Functional Ambulation Category (FAC), Berg Balance Scale, Timed Up and Go (TUG) test, Modified Ashworth Scale (MAS), and a validated Bengali version of the EuroQol quality-of-life questionnaire. Usability and acceptability will be assessed via the Post-Study System Usability Questionnaire (PSSUQ) at study completion.

Data will be collected on standardized case report forms and entered into a password-protected, anonymized electronic database, with independent verification and monthly adverse-event review by a safety monitor not involved in training delivery. Analysis will follow an intention-to-treat approach (with a secondary per-protocol analysis), using descriptive statistics for safety/feasibility outcomes and paired/unpaired t-tests or Wilcoxon signed-rank tests (as appropriate for data distribution) to compare baseline versus follow-up efficacy outcomes, with statistical significance set at p<0.05 (two-tailed).

This pilot study is intended to generate foundational safety, feasibility, and effect-size data to inform the design of a future, adequately powered randomized controlled trial and to guide responsible implementation of robotic gait rehabilitation technology within the Bangladeshi healthcare context.

Inclusion criteria

• Lower-limb motor dysfunction from one of the following: (a) stroke (onset 2-24 months), (b) incomplete spinal-cord injury (neurological level T12 and below, ASIA C or D), (c) orthopedic surgery (e.g., knee/hip replacement) with persistent gait impairment >3 months post-surgery
• Age >18 and ≤60 years
• Able to provide informed consent and understand instructions
• Weight ≤100 kg and height within device adjustable range (per manufacturer specification)
• Medically stable and cleared by physician for exoskeleton use (no active infection, uncontrolled cardiac/respiratory disease, severe osteoporosis, uncontrolled epilepsy, or untreated DVT)

Exclusion criteria

• Complete spinal cord injury with inability to bear any weight
• Severe cognitive impairment (e.g., MMSE <24) preventing safe participation
• Severe spasticity (Modified Ashworth Scale >3) in lower limbs
• Unstable fractures, severe hip/knee contractures (>30° fixed flexion), or severe osteoarthritis requiring imminent surgery
• Uncontrolled cardiac arrhythmia, pacemaker incompatibility, or implanted electronic device incompatible with robot sensors
• Pregnancy