Locomotor training is an established rehabilitation approach that is beneficial for improving walking function in individuals with spinal cord injuries (SCIs). This approach focuses on repetitive practice and appropriate stepping movements to activate spinal neural networks and promote rhythmic motor output associated with walking. Assistance with stepping movements is often provided by physical therapists and trainers, but this can be costly and difficult to deliver in the cost-constrained U.S. healthcare market. Robotic devices have been used as an alternate method to deliver locomotor training, but current robotic approaches often lack the natural movement variations that characterize normal human stepping. Furthermore, studies to compare locomotor training approaches have not shown any specific benefits of using robotic devices. A new type of robotic device has emerged that uses an individual's muscle activation and stepping movements to control the robot during walking. This adaptive robotic device adjusts to the user's intentions and can assist with stepping during locomotor training in a manner that matches natural human stepping. While this type of adaptive robot has been preliminarily tested, the safety and efficacy of locomotor training using adaptive robotics are not well-established in patients with SCI. This is a critical step to determine if individuals with SCI may benefit from use of this device and for preliminary adoption of this technology. Recent studies have used the Cyberdyne Hybrid Assistive Limb (HAL) to deliver locomotor training and have reported outcomes suggesting that the HAL adaptive robot is safe and efficacious for walking rehabilitation in European SCI patients. Therefore this study will use the HAL adaptive robot to deliver locomotor training. This research is necessary to determine if use of the HAL is potentially beneficial and warranted for use with locomotor training and SCI patients receiving care in the U.S. Results of this study may contribute to the development and implementation of effective walking rehabilitation approaches for people with SCIs.

The purpose of this study is to examine the safety and efficacy of locomotor training using adaptive robotics in adults with chronic SCI. Safety will be determined by monitoring of adverse responses such as skin irritation, pain, changes in spasticity and function. Preliminary efficacy for improving walking function will be determined by tests of walking speed and endurance prior to and following 60 daily sessions of locomotor training using adaptive robots.

Specific Aims:

Specific Aim 1: Test the hypothesis that locomotor training using adaptive robotics such as the Cyberdyne Hybrid Assistive Limb (HAL) is safe for individuals with chronic incomplete spinal cord injury (SCI). Safety will be demonstrated by an adverse response rate that does not exceed the frequency and severity of adverse responses reported for other well-established locomotor rehabilitation approaches. Safety will be assessed by monitoring of specific conditions such as skin integrity, pain, and spasticity.

Specific Aim 2: Test the hypothesis that locomotor training using adaptive robotics such as the Cyberdyne HAL (5x/week for 12 weeks, 60 sessions, 2 hours each) is efficacious for improving walking function in adults with chronic incomplete SCIs. Walking function may be assessed using standard clinical tests to measure walking speed and walking endurance. A battery of clinical tests (listed in Outcome Measures) will be selected for use based on each participant's functional capabilities.

To address the aims of the study, the investigators will use a pre-post repeated measures study design. Following phone and in-person screenings and physician approval, individuals will provide informed consent to the study procedures. Non-invasive tests of physical function and health will be conducted prior to and following 60 sessions of locomotor training using the HAL, an adaptive robotic device that is custom fitted to each individual to provide assistance to the lower limbs during locomotor training.

Subject recruitment: Individuals with chronic SCI (>1 year) who meet the given enrollment criteria (see inclusion and exclusion criteria) will be included for this study. Recruitment will occur from within the Brooks Health System which includes the Brooks Cybernic Treatment Center, as well as from their healthcare providers and advertisements in the community.

Inclusion Criteria:

1. Adults 18 - 80 years old
2. Diagnosed with chronic, sensory or motor incomplete spinal cord injury (ASIA Impairment Scale (AIS) B, C, D), >1 year post injury
3. Medically stable with no acute illness, infections
4. Obtained physician approval to participate in study procedures
5. Able to walk 10 feet with or without assistance, gait assistive devices and/or orthotics
6. Able to provide informed consent

Exclusion Criteria:

1. Additional neurologic conditions such multiple sclerosis, Parkinson's disease, stroke, brain injury
2. Presence of unstable or uncontrolled medical conditions such as cardiovascular disease, myocardial infarction (<1 year), pulmonary infection or illness, renal disease, autonomic dysreflexia, infections, pain, heterotopic ossification
3. Cognitive or communication impairments limiting communication with study staff or ability to provide informed consent
4. Lower extremity joint contractures limiting the ability to stand upright and practice walking
5. Skin lesions or wounds affecting participation in walking rehabilitation
6. Acute or unstable fracture, diagnosis of osteoarthritis or bone impairments affecting safe participation in walking rehabilitation
7. Spasticity or uncontrolled movements limiting participation in walking rehabilitation
8. Body weight or height that is incompatible with safe use of the HAL and/or use of a support harness and body weight support system
9. Pain that limits walking or participation in walking rehabilitation
10. Current participation in rehabilitation to address walking function
11. Botox injections in lower extremity muscles affecting walking function within 4 months of study enrollment
12. Legal blindness or severe visual impairment
13. Known pregnancy
14. Pacemaker or medical device implants which may interfere with the use of the HAL