Use it-or lose it.
That familiar advice rings particularly true for survivors of a stroke. Each year 700,000 people in the United States have a stroke. About three-quarters survive, but more than half suffer from impaired movement. Their route to recovery is long and tough, as they painfully relearn how to use an arm or a leg by going through the motions over and over again with a physical or occupational therapist.Unfortunately, all that therapist time gets very expensive, and health insurers have dramatically cut the amount of therapy they will reimburse. “When I started, it was three to five months,” says Susan Fasoli, an MIT researcher and occupational therapist. “Now we’re lucky if we get patients for three weeks.”
Given less therapy, many stroke victims never recover as well as they might. “The more therapy you do and the more intense the therapy is, the better your ability to recover function after a stroke,” says Richard Mahoney, president of Phybotics, a robotics startup in Westmont, NJ. But if patients can function-even one-handed-their insurance firms may tell them that their rehabilitation is done. And if training is overly focused on a few very specific tasks, it may even impede a more general recovery.
Enter rehabilitation robots, which can ease the therapist’s load by delivering certain treatments very efficiently, in some cases, achieving dramatically better results than conventional therapy alone.
Researched for more than a decade, rehabilitation robots are being tested on patients throughout the United States, Europe and Asia. And they’re just starting to appear in clinics for more general use. Interactive Motion Technologies in Cambridge, MA, has sold about two dozen systems for arm therapy, priced at $5,000 to $70,000, says company director Robert Parlow. Another market leader, Hocoma of Staefa, Switzerland, offers a robotic gait system, which combines with a treadmill to aid patients re-learning to walk.
Proving Patient Progress
Interactive Motion’s robots are based on pioneering work by MIT researchers Neville Hogan and Hermano Igo Krebs (see “Robotic Road to Recovery,” TR November 1999). Optimized over the years, the basic design is a robotic arm that works in two dimensions and aids recovery of shoulder and elbow movement by carefully guiding the patient’s partly paralyzed arm through appropriate motions, over and over. Patients watch a video screen and play “the world’s most boring video game” with their disabled arm, says Hogan, a professor of mechanical engineering and of brain and cognitive sciences, as well as director of the MIT Arm Lab. The robot can exercise them more precisely than a human therapist, and it doesn’t tire. “Within an hour, you can do about 1,000 repetitions of motion-much more than anyone would ever get within the context of a conventional therapist,” says Fasoli.
According to Hogan, pilot studies have repeatedly demonstrated the value of the robotic approach, advocates say. Patients using the robot have shown twice the functional improvement, on standard clinical scales, as patients given conventional therapy, over the same treatment periods. And they continue to make progress in treatment programs months or years after the stroke.
“I think it’s going to be a great adjunctive therapy,” says Richard Hughes, a physical therapist at Spaulding Rehabilitation Hospital in Boston, which is doing research along with the MIT group. “Patients generally like the robot. Many think of it as similar to a video game.” Using the robot in a highly structured way makes it easier for them to perform the motions-almost like patrons of a health club on a workout machine, he adds.
The MIT group is collaborating with rehabilitation clinics in pilot tests of new devices that add vertical motion and wrist movement capabilities to the robot arm. Results from early tests are encouraging, Hogan says. The lab is also working on systems for lower-limb recovery, and he envisions a family of machines.