Robots Give Stroke Patients a Helping Hand
Computer-Assisted Techniques Help Patients to Better Grab, Release Objects
Feb. 20, 2009 (San Diego) -- Stroke patients who were lent a robotic hand regained some lost strength and motor skills, researchers report.
Steven C. Cramer, MD, director of the Stroke Center at the University of California, Irvine, and colleagues studied 15 stroke patients with partial paralysis and weakness in their right hands and arms. Four months to 10 years after their stroke, patients began a two-week course of robotic therapy.
All 15 could pick up and release objects more easily after treatment. And the greater their disability at the start of the therapy, the greater their recovery, according to the findings, presented at the American Stroke Association’s International Stroke Conference 2009.
Edward J. Mendelsohn, MD, of Manhattan Rehabilitation Services in N.Y., says that it’s noteworthy that patients experienced gains in motor function even though they didn’t undergo treatment until months or years after their strokes.
“Usually, most return of function occurs within the first three months,” says Mendelsohn, who wasn’t involved with the study. “But using [robots, video games, and relaxation exercises], we’re now seeing improvements in range of motion and in function in patients who had strokes five or six years earlier. Seeing any improvement at all years after the stroke is significant.”
Sensory Feedback Helps Brain to Recall
In the study, seven patients were given a robotic technique called motor therapy, in which computers guide patients while they relearn how to pick up and release objects.
The other eight patients received a more complex robotic approach called premotor therapy, which requires grasping, releasing, and resting in synch with timed visual cues.
Cramer offers an example. “In response to one of three color cues, patients try to open, then close, then rest, their weak hand. After they do the best they can, the robot completes the movement to the extent the patient couldn’t,” he says.
The reason the computer kicks in at that point, Cramer says, is because “sensory feedback is a normal part of motor performance. We completed the movement in these instances so the brain could experience the signals of a completed correct movement. That helps the brain to recall what to do the next time," he says.
On tests performed one month after treatment ended, people with less severe damage to their motor skills showed bigger improvements after the premotor therapy than the motor therapy. Patients with greater physical impairments benefited equally from both robotic techniques.
“The status of a patient’s motor system at the beginning of therapy is very much related to how treatment will affect them,” Cramer says.