Improved versions of three different types of lower body exoskeletons are in use at various rehab facilities across the United States and throughout Europe. The ReWalk has received FDA approval. The Ekso and the Indego both plan on following soon. Each manufacturer sees its product as a way for people to gain greater mobility and freedom.
Increasingly clinicians are using the devices to assist in relearning proper stepping techniques and reeducating the nervous system concerning normal walking patterns. Some therapists see them as a way to maximize the number of steps per session as opposed to other walking methods.
“We are able to get individuals with incomplete injuries up and walking. Our hope is that this may also provide the nervous system with appropriate retraining to facilitate functional recovery,” says Candy Tefertiller, Craig’s director of PT.
Exos, as they are known as a class, may also offer people a way of ambulating through narrow doorways, into once inaccessible places and a new world of possibilities. The devices are much improved from three years ago — more adjustable, refined, sophisticated and presumably fast enough to get through a crosswalk before the light changes. They still bring to mind a headless cyborg, especially the ReWalk and Ekso, with the shoulder straps and backpack.
“Exos can be used for gait training, mobility or exercise,” says physical therapist Clare Hartigan, who has worked with all three devices at Shepherd Center. “They often allow us to do more steps per session than other forms of walking therapy.”
Preliminary study reports have suggested that lower extremity exos may have benefits such as improved balance, conditioning, neuromuscular cortical activity; reduction in spasticity and pain, as well as increased personal well-being and quality of life. Other trials have suggested improvements in step speed, stride length and symmetry with stroke survivors, although results were inconclusive with SCI; no trial results exist for MS or TBI. In general, they all employ sensors to monitor trunk position and activate with user position changes.
But don’t plan on retiring those wheels just yet; these exoskeletons are meant to complement chairs, not replace them. They come with price tags as high as $70,000 and no proven track record of reliability. The FDA requires a product life of five million cycles (or steps) for approval.
Exos remain works in progress. As yet, no rigorous research exists which allows for any cause-effect conclusions regarding any medical benefits. Any claims of benefits cited below are based on manufacturers’ studies. Or, as Kevin Ogar put it, “I’d use it the same as my braces, to get around my house, to do certain chores, but I wouldn’t get rid of the chair.”
ReWalk: First to Get FDA Approval
ReWalk claims to be the most widely used and most studied exo, as well as the first to gain FDA approval for sale to individuals.
The company sees its device as appropriate for both gait training and personal mobility. The device responds to upper-body motions, which are monitored by a sensor that triggers both stepping and overall gait patterns for walking and shifting from sitting to standing. Users are free to use their hands.
The personal ReWalk has improved since 2012, with better electronics, upgraded sensors, an all-black look and other user-friendly changes. The battery life provides on average 3.5 hours of actual walking, which ReWalk considers all-day use. The device is recommended for T4 and lower injuries and requires buyers be trained and tested at one of the company’s advanced training centers.
ReWalk ($71,600) says it has been successful in securing full reimbursement from an insurance carrier for a U.S. purchaser, with more in process. The company has set up a department devoted to reimbursement and will go to insurance companies on behalf of purchasers, pitching benefits — improved balance, core strength, bowel/bladder function, bone density, body composition, fitness and sleep patterns, as well as decreased pain and spasticity and reduced hospitalizations and dependence on medications. The statistics are based on small internal studies and testimonials from “ReWalkers.”
Ekso Bionics: Programmable Assisted Walking
“Right now we’re focusing on building the best rehabilitation device possible for gait training,” says Darrell Musick, Ekso Bionics vice president of clinical services. “We can get in hundreds of steps in a session in a safe way while compensating for muscle weakness. People who have used both our current GT and the older models see significant improvements and now find it easier to use,” Musick adds.
The user shifts weight and activates footplate sensors that initiate each step. Battery-powered motors compensate for weak or non-existent muscle function. The Ekso now offers a variable assist mode, an automatic mode and a manual mode and can be programmed to walk at a certain speed and with a specific stride length. If the user does nothing, the device will do all the work; when the user engages whatever leg muscles they have available, the device senses how much assistance is needed and backs off, like a cruise control. The assistance levels can be reduced or turned off on one side or the other — for those dealing with hemiplegia or asymmetrical strength.
The Ekso is presently a “Class II pending” medical device (medium safety risk) to provide functional-based rehabilitation, over-ground gait training, and upright weight-bearing exercise under the supervision of a physical therapist, and is designed to fit a wide range of users.
“The Ekso GT supports the re-learning of a correct step pattern and allows more steps at a faster speed than with traditional rehabilitation,” adds scientist Karen Nolan of the Kessler Foundation Research Center.
Indego: Lightweight, Wheelchair Compatible
Parker-Hannifin is developing the Indego — for relearning walking as well as a personal mobility assistive device for individuals who are partially or fully walking-impaired. The company sees its device as being used in conjunction with a chair, not replacing it — for greater independence.
“We see the Indego as a rehab training device for SCI, MS, stroke and other neurological problems, and in institutions as a rehab tool to relearn the principles of muscle motor control necessary for walking,” explains Achilleas Dorotheou, vice president of human motion and control for Parker-Hannifin about the device that was originally developed at Vanderbilt University
“Indego allows individuals with impairments to stand up and walk while the device compensates for weak or nonfunctioning muscles,” says Dorotheou. “The device provides the key principles for motor learning, while requiring active participation through postural cues and user-driven initiation. It signals the user as to what is about to happen with a mild vibration and LED light, indicating a step is about to initiate. That facilitates the kind of locomotor and gait-training necessary for neuroplasticity.”
“It’s pretty simple, says T11 Kevin Ogar, injured one year and in his 12th Indego session in Denver: “Lean forward and take a step.”
This device features a five-piece modular design — a back component that wraps around the pelvis and lower back, two upper leg pieces, and two lower leg pieces with integrated ankle-foot-orthoses. They snap together quickly and can be carried in a large bag. I watched Ogar put it on in less than seven minutes. The manufacturer has made some changes. It is now lighter (27 pounds); more comfortably fitting; made of stronger material; easier to size, set up, put on and take off; with improved LED status indicators and software changes for smooth, intuitive, safe operation. Parameters such as stride length can be adjusted with an app.
Unlike other exos, wheelers can wear the Indego while wheeling. It’s strong enough to support individuals with level 3 spasticity (on a scale from 1-4). All components are housed in hard plastic, making them durable enough for everyday use.
This article was funded by the U. S. Department of Education’s National Institute on Disability and Rehabilitation Research, Grant #H133N0110006. Opinions expressed in this article do not necessarily reflect the opinions of NIDRR.
Activity-Based Vertical Rehab
You’ve seen body weight supported treadmill training on television, the Internet, or perhaps at your rehab facility. The user is suspended in a harness above a treadmill and made to “walk” either by having people repeatedly moving their legs in a walking motion, or is strapped into an elaborate robotic machine which does the same.
Research suggests that high doses of activity-based therapy may facilitate some recovery of function, especially with newer and incomplete injuries. The degree of recovery is sometimes more dependent on the amount rather than the specific type of exercise. Body weight supported treadmill training and other activity-based therapies address the body as a whole, especially strengthening the core and facilitating an appropriate walking pattern.
Shepherd Center conducted an intensive activity-based therapy clinical trial in 2010, a 24-week long rigorous exercise regimen combining locomotor training, developmental sequencing, strengthening and resistance training for up to nine hours a week. They found those therapies “activate the neuromuscular system below the level of the lesion, with the goal of retraining the nervous system to recover specific motor tasks,” according to Mike Jones, vice president of research and technology at Shepherd.
The repetitive motions of activity-based therapy apparently coax undamaged circuits in the spinal cord itself to reawaken, sometimes establishing new pathways. Over time, the axiom holds — “neurons that fire together wire together” — and the new connections and motion become stronger and more natural. The big question is how much descending input is necessary and sufficient for functional movement below the injury level.
Incomplete injuries experience greater functional and neurological recovery while complete injuries show improvement in activities of daily living. The findings suggest that functional recovery may occur in response to intensive training, though it remains uncertain as to whether it occurs due to compensation or neural plastic changes.
The Reeve Foundation NeuroRecovery Network is currently investigating what effects locomotor training might have on autonomic functions such as bowel, bladder and sexual function. Brad Boe, injured six months, has been doing body weight supported treadmill training for a month (90 minutes/five times weekly) along with some upper-body e-stim work. “I can now do some over-ground walking using a walker,” says the C4-5 quad. “I have more function in arms and fingers.”
Most PTs recommend several sessions a week for a minimum of three months in order to see any significant and lasting results. Locomotor training, with at least one of the aforementioned machines, is now relatively accessible at most major SCI rehab facilities, though not necessarily affordable. Craig Hospital, a nonprofit facility, charges $85 for an hour session of locomotor and/or other personal training. In cases where insurance covers the treatment, the patient may still be responsible for co-pays. For those who do not live near a center, FES bikes are available for home use, but cost between $15,000 and $17,000.