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Device could be mainstream in two to five years
A pioneering robotic device being tested at the Rehabilitation Institute of Chicago (RIC) could change the way therapists retrain patients with paralysis to walk. The Swiss-manufactured exoskeleton robot, called the Lokomat, delivers power to the hip and knee joints of the patient, whose legs are strapped to the machine. The patient is suspended over a treadmill with a certain percentage of the body weight supported by a harness. The Lokomat moves the patient’s legs in a walking pattern.
Researchers say the repetitive training in movement can, in time, help patients redevelop and regain functional walking patterns. "Everyone gets stronger; everyone gets faster," says George Hornby, PhD, PT, research assistant professor at RIC. "Some patients improve their quality of walking, so instead of dragging their leg behind them, they may be able to move forward a little bit. There certainly is a clinical benefit. It’s just deciding how good is this benefit and is it as good as therapists doing the training."
RIC started using the U.S. Food and Drug Administration (FDA)-approved Lokomat in clinical trials last year on patients with spinal cord injuries who can move parts of their legs. In the studies, all patients improved their walking ability. Work is under way to determine whether patients using the robot have better outcomes than those undergoing traditional manual therapy in which therapists support the patient’s body weight and move their legs in a walking pattern. A study also is comparing the robot outcomes to traditional overground therapy where patients try to walk using parallel bars or other assistive devices.
"When therapists do it, you need at least three people; whereas with the robot, you need only one person to run the machine. Also, therapists will peter out in five to 10 minutes whereas the robot can keep on going," he adds. "The robot can go for 45 minutes or an hour, and there’s no way a therapist could move the patient’s leg for that much time."
The other issue is that manual body weight-supported treadmill training, while highly effective, rarely is done in the clinic because of the number of therapists required and most insurance companies will not cover that cost, he says. Most therapists have patients practice walking over ground with the help of parallel bars or a splint.
"That’s good, but it’s not getting at the correct sensory information you could get from practicing stepping behaviors on a treadmill over and over," Hornby points out. "With the robot, you’re not relying on your hands to push up on parallel bars. If you compare the robot to overground, conventional gait training, that’s when the robot will most likely show much higher gains. We’re in the middle of that study now."
The Lokomat currently costs about $250,000, a price that researchers say likely will drop as competitors enter the market. Within two to five years, with a lower cost and more research to back it up, the machine likely will be found in more hospitals. "Any major rehabilitation center should look at this. The major cities should all definitely have this," he says.
Anecdotally, the machine has worked wonders for some patients. "We have patients who can walk now; and if you take all the statistics across spinal cord injury patients, their chance of walking after two years is 10% to 30%," Hornby says.
"One patient was a 13-year-old girl who had a diving accident and had no movement in her legs for five weeks. We trained her for eight weeks in the robot, and she was able to walk 250 feet. Statistically, she only had a 10% to 30% chance of walking two years after the injury. Now it’s been a year since her injury, and she doesn’t use a wheelchair at all; and she walks over ground with the help of crutches," he adds.
The device is likely to be most helpful for those patients who are the weakest. David Zemon, MS, PT, a research physical therapist at RIC, says the Lokomat is a wonderful first step and an engineering marvel. But for patients with more strength, it may not be as effective as manual training by a therapist. "The patient could practically fall asleep in the machine because the robot keeps on going. It doesn’t respond to the amount of force from the patient like a therapist could," he says. "Engineers are working on ways to make it more compliant."
Zemon says researchers hope to find a happy medium between the robotic repetition and allowing patients to learn from making mistakes walking on their own. "The machine corrects the patient’s mistakes a lot, so the patient is walking the same way every time," he says. "The therapist can respond to the patients and allow them to make mistakes. The robot is a great training tool, but patients still need to practice walking over ground."
Zemon says therapists love the Lokomat. "Everyone likes the pattern. It moves in such a controlled gaitlike pattern," he says.
Researchers say the Lokomat also potentially could be useful for patients with other neurological diagnoses such as multiple sclerosis, cerebral palsy, head injury, and Parkinson’s disease.
Need more information?
George Hornby, PhD, PT, Research Assistant Professor, Rehabilitation Institute of Chicago, 345 E. Superior St., Chicago, IL 60611. Telephone: (312) 238-1397.
David Zemon, MS, PT, Research Physical Therapist, Rehabilitation Institute of Chicago. Telephone: (312) 238-1396.