The robot exercises patients' limbs much like a physical or occupational therapist would. In this study, stroke survivors with reduced use of one arm performed robot-directed movement exercises and regained some ability to move their affected arm up to five years after a stroke.
In the future, the device could act as a home therapist, say investigators.
"The MIT-Manus robot is an exciting tool that has wonderful potential," says Susan Fasoli, ScD, OTR, the study's lead author and a post-doctoral associate in mechanical engineering at Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts. "The robot could be ideal for home therapy because it can be programmed remotely by hooking it up to a phone line."
Stroke is a leading cause of serious, long-term disability in the United States. About 4.6 million stroke survivors are alive today.
Traditional belief is that most recovery will happen within the first six months after a stroke, so physical and occupational therapy is concentrated during this time. This research suggests that robot-assisted sensorimotor therapy can help survivors recover movement abilities years later.
When an arm or leg doesn't recover function during that early period "most patients learn to compensate for the loss and make little or no attempt to use the impaired limb, which leads to even more disability," says Fasoli.
To test the theory that recovery could continue long term, Fasoli and other team members used a robot designed by MIT engineers for use in physical and occupational therapy. The robot, designed to stand on a table, has an arm that extends for about two feet. The patient's affected arm is secured into a supportive arm trough that is attached to the end of the robot's arm. Once the patient's arm is secured, the robot moves the arm, working the patient through a series of programmed motions.
Rehabilitation therapists think this repetitive motion can rebuild nerve pathways from the brain to the injured limb. "This cortical reorganization appears to continue even years after the initial injury," says Fasoli.
The robot also has several advantages over traditional physical or occupational therapy. "Continuing rehabilitation with a physical or occupational therapist is very labor intensive and long term it can be very costly," she says. The robot, by contrast, simply has to be programmed and plugged in and it's ready for a therapy session. Moreover, the robot is "very compliant and versatile. Although it can be programmed to offer some resistance to strengthen a patient's movements, it can also help a weaker person complete difficult exercises," she says.
MIT-Manus was first used for inpatient therapy at Burke Rehabilitation Hospital, White Plains, New York, in two studies with patients who'd had a stroke within a month. The success of that research led to this study of long-time stroke survivors.
In the new study at Spaulding Rehabilitation Hospital in Boston, Fasoli enrolled 11 men and 2 women, average age 60, who had suffered a stroke that affected movement on one side of their body during the previous one to five years. They were all living in the community, either alone or with a spouse or caregiver. All had impaired use of one arm, which was confirmed during a four-week observation period before beginning robot-assisted therapy.
During a six-week treatment period, enrollees had one-hour therapy sessions with the robot three times a week. The robot-directed exercises were aimed at improving movement in the shoulder and upper arm, Fasoli says.
"At the end of the treatment we observed improved movement abilities in the exercised limb," she says. But although patients had less impairment - meaning they could move the arm better than before beginning treatment - there was no increase in abnormal muscle tone, she says.
The results are encouraging, says Fasoli, but she adds that real functional improvements will come when survivors can improve "hand and wrist movements." This is the goal of a future robot study. The robot is now commercially available for research and clinical use and has been renamed InMotion2.
Fasoli predicts that MIT-Manus and other high-tech approaches to rehabilitation will make stroke rehabilitation more affordable and more convenient.
Fasoli's co-authors are Hermano I. Krebs, Ph.D.; Joel Stein, M.D.; Richard Hughes, M.S., P.T.; Anne Mccarthy-Jacobson, M.S., P.T.; Walter Frontera, M.D., Ph.D.; and Neville Hogan, Ph.D.