One Step Closer

Walking Exoskeletons Inching Toward Retail

Indego exoskeleton

Michael Gore tests the Indego with backup from Clare Hartigan, Shepherd Center. Photo by Christopher Martin

Even when the ability to walk no longer exists, the strong desire to do so can remain. Plus from a medical standpoint, standing and walking are beneficial, helping to improve respiration, digestion and circulation.

For people with spinal cord injury, the nearest and greatest technology hope for walking again is the current class of exoskeletons. There are several such devices, including the ReWalk from Argo Medical Technologies in Israel; the Ekso from Ekso Bionics in Richmond, Calif.; and the Parastep from Therapeutic Alliances Inc. in Fairborn, Ohio.

But the one getting the most attention recently is Vanderbilt University’s Powered Exoskeleton, recently named Indego. The Vanderbilt Center for Intelligent Mechatronics says of its exoskeleton, “It uses onboard embedded microprocessors and sensors to determine the user’s current state and intentions, and provides joint torques at the hips and knees to generate motion.”

Parker Hannifin Corp.—a manufacturer of motion and control technologies and systems for the mobile, industrial and aerospace markets that had $13 billion in sales last year—bought licensing rights to the Vanderbilt device in October. In its licensing announcement, Parker Hannifin noted that the exoskeleton was “currently being tested and refined through clinical research” at the Shepherd Center in Atlanta.

Testing Exoskeletons

While all of these exoskeletons share the same basic goal—to support and enable walking—they differ in design and how they accomplish that task.

Clare Hartigan, MPT, BSBio, is a physical therapist and Shepherd Center researcher who’s spent significant time working with several exoskeletons. In fact, she’s tested the ReWalk and Ekso, and the Shepherd Center worked closely with Vanderbilt University to develop the Indego.

Hartigan says. “It was a collaborative research effort that began in early 2010, and Vanderbilt University had this idea they were developing: an exoskeleton that was light weight and had functional electrical stimulation, and the person could sit in their own wheelchair (while wearing the device).”

Several years later, Hartigan remains excited about the exoskeleton’s possibilities.

“We’ve had tremendous success with the Vanderbilt device and how it’s been developed,” she says. “Shepherd continues to do studies and clinical trials with the device, not just for spinal cord injury, but also stroke.”

Hartigan points out that with Indego, “There are 12 different muscle groups that you can electrically stimulate while you’re in the device.”

Comparing & Contrasting Devices

There are more reasons to get excited about Indego, Hartigan notes. First, it’s about half the weight of the other devices and can be broken down and stored in a backpack, which makes it more feasible to put on, use, take off and store the device without help.

Second, the Parker exoskeleton has functional electrical stimulation (FES).

“The big buzzword in therapy now is ‘Is it activity based?’ ” Hartigan explains. “Can you actually be doing something functional while you’re using this equipment?”

The Parastep, she points out, “was a device that was made for people with paraplegia primarily around the T10 level because they respond to electric stim. It was a combination of electrodes in the proximal part of your body and braces on the lower part of the body. And you can stimulate a step through Parastep.”

One of the differences between Parastep and Indego, however: “If you see people walk in the ParaStep, it’s much more labor intensive. One of our subjects, Michael, has actually walked around in the Parker device for up to four hours all over the building: up and down stairs, curbs, ramps, elevators. And he is not tired. That’s mainly because the exoskeleton is the thing that is supporting his weight. He’s just using his upper body for balance and to guide his assistive device.”

In her experience of working with patients using long leg braces, Hartigan says, “After about 30 minutes to an hour maximum, they’re wiped out. They have increased incidence of shoulder issues, and they’re at risk for shoulder injury. But this (Parker) device holds the weight, supports the weight. You have to have good range of motion so you can get into a position to just push up a little bit—like if you’re in a wheelchair and you want to stand. You have to have the shoulder range of motion to get your shoulders back with the forearm crutches to be able to push. It’s less than 25 percent of your body weight—just a little bit of a push initiates a stand.”

Exoskeletons Navigate the Real World

Indego exoskeleton

Brian Shaffer stands tall in the Indego exoskeleton, a creation of Vanderbilt University. Photo courtesy Joe Howell, Vanderbilt University

Patients using exoskeletons also use forearm crutches or walkers to help them maintain balance while walking.

“I love the Ekso because it gets people up, it gets people walking,” Hartigan says. “You can have a high level of injury and be in it. With the Ekso, you can use a walker or forearm crutches.”

But due to the Ekso’s width, Hartigan says its users need an extra-wide walker, which can be difficult to maneuver in smaller spaces.

“It’s fine for open areas,” she says. “But if you’re going to be walking around the house or in and out of bathrooms, it may be difficult.”

With either forearm crutches or a walker, the Ekso currently is recommended only on level surfaces. (“None of these devices is approved for home use yet,” Hartigan points out.)

The ReWalk, unlike other exoskeletons, uses a “double-crutch” forward gait pattern: The user moves both crutches forward, then takes a step.

“The ReWalk can only be used with forearm crutches,” Hartigan says. “Two crutches at a time, step. Two crutches at a time, step. It’s not a normal, reciprocal gait pattern of arm, leg, arm, leg. So with the ReWalk, you cannot use a walker.”

The Indego, with its sleeker design and lighter weight, can be used with forearm crutches or a standard-width walker—and on surfaces including ramps, stairs and curbs.

“The reason it’s important for patients to have a choice of what type of device they can use is it opens up the world in terms of independence and activities of daily living,” Hartigan notes. “Say a subject with any of the exoskeletons wanted to walk into the kitchen, get something out of the freezer or something from a high cupboard, or walk into the bedroom and get something out of a closet. If you’re using forearm crutches and you’re a complete injury, you’re not going to be able to be super safe and let go of a forearm crutch to do that. But if you have a walker, you’re extremely steady.”

Complete vs. Incomplete SCI

Hartigan says Indego is also capable of adjusting the amount of help it offers, depending on what its user needs.

“The Parker exoskeleton is the only device that has variable robotic assist, so if the patient can do more, the robot does less. It’s not been proven yet—the only thing we’ve looked at with the Parker device is pure mobility—but you know when people start on FES bikes and they show increases in strength? If you’re an incomplete in any way, muscle wise, by having the electric stimulation on we hope in the future that it would also show strengthening benefits.”

Makers of some exoskeletons have said patients with lower cervical injuries could use them, but Hartigan adds, “Most of those have been incomplete patients. The highest that I’m aware of for a complete patient was the physician here at Shepherd who’s a T1/T2 complete. He required a walker and the assist of two people. But he could do it—he could take some steps. Probably if you’re a T6 or lower, you could become completely independent for the Parker device, taking it on and off and all that.”

And Hartigan believes the Indego could help patients with other mobility-related conditions, as well: stroke, multiple sclerosis, spina bifida and cerebral palsy.

“Shepherd has a very large base of patients with multiple sclerosis,” she notes, “and I think for MS, this is going to have a lot of benefits, too. Fatigue is such an issue with MS; you have people who can walk inside the house, but that’s about it. There are a lot of patients that have MS and their upper bodies are still pretty good; it’s mainly just their lower bodies. It would be perfect for them.”

The Funding Question

Hartigan says she hopes exoskeletons will eventually be used in both home and rehab facility settings, but before that can happen, there is the all-important question of cost.

The Parastep, Hartigan points out, is Medicare reimbursable. But in general, current costs of exoskeletons put them out of reach for many medical facilities and certainly, most consumers.“Now that Parker is behind it, they’re going to do what they can to make it very financially accessible to rehab centers and to patients,” she says. “There’s not been any real discussions about price, but we do know that Ekso and ReWalk are selling for well over $100,000 to rehab centers. You can buy an Ekso and a Rewalk for personal use in Europe, and those devices were also sold for over $100,000.”

Hartigan said Parker Hannifin is committed to making its device “more financially accessible, not just for rehab centers for training, but for patients who want to buy it.”

The Indego that comes to market—the target date is 2014—is also likely to be even lighter weight and slimmer than the current model being tested.

Already, Hartigan says she and her Shepherd Center colleagues use videos of the various exoskeletons to educate and motivate their in-patient clients.

“We say to them, ‘For these devices right now, your weight has to be 220 lbs. or less, you have to have good range of motion, your skin has to be intact.’ That’s a big thing, because people go home, and their hips and ankles get tight. They don’t see the importance of keeping them stretched out; they don’t think they’re ever going to walk again. It’s really important that patients get that message now: Keep your weight down and upper-body strength good.”

Callout

Would you like to be involved in a Shepherd Center study? Click here for details.

About the Author

Laurie Watanabe is the editor of Mobility Management. She can be reached at lwatanabe@1105media.com.