Robotic arm lends a hand after stroke
In the U.S., stroke is a major cause of long-term disability which affects 700,000 people annually. Most of them are over 65 years old and some have difficulties grasping objects after their stroke. This is why Californian researchers have developed a robotic therapy which helps restore hand use after stroke. The Hand-Wrist Assisting Robotic Device (HoWARD) has successfully been tested on seven women and six men who had suffered a stroke at least three months before the study. These results, while encouraging, need to be balanced. There must be enough residual motor power in the arm and hand of stroke patients to initiate some movement for this robotic therapy to work.
The HoWARD robotic device has been developed by Steven C. Cramer, an associate professor in neurology, anatomy and neurobiology at University of California, Irvine (UCI), and his colleagues. Here are some of his comments.
"Most spontaneous improvement in function occurs in the first three months after a stroke, and after that things tend to plateau," Cramer said. "Robot-assisted therapy may help rewire the brain and make weak limbs move better long afterwards."
"The HOWARD therapy isn't passive; the patient has to jumpstart the program and initiate the motor command," Cramer said. "But if the hand is weak and can only budge one-tenth of an inch, the robot helps to complete the task so the brain relearns what it's like to make the full movement."
Below is a diagram showing the design of the HoWARD robotic device (Credit: UCI). Here is a link to larger version of this diagram.
Now, let's look at how HoWARD was tested and how it helped stroke patients.
In the UCI study, each patient, average age 63, received 15 two-hour therapy sessions, spread over three weeks, designed to improve their ability to grasp and release objects. All worked with HOWARD for the 15 sessions. For seven patients, HOWARD shaped and helped complete movements across all sessions, while six had complete support from HOWARD for only the second half of the sessions.
At the end of three weeks, all patients had improved in their ability to grasp and release objects. Their average score on an Action Research Arm Test -- which measures the ability to perform such real-world tasks as grasping a block, gripping a drinking glass, pinching to pick up a small marble or ball bearing, and putting your hand on your head -- improved by nearly 10 percent. And their average score rose by nearly 20 percent on the Box-and-Blocks Test, which assesses manual dexterity.
An article from the Atlanta Journal Constitution, "Robot Hand May Speed Stroke Recovery" (February 7, 2007), gives additional details about this robotic therapy, saying that this technique could really help patients.
"The implementation of robotics coupled with virtual reality training holds promise for motor recovery and, hopefully, functional recovery for chronic stroke patients," said Dr. Ira G. Rashbaum, chief of stroke rehabilitation at New York University Medical Center in New York City. "I'm pleased to see the researchers combined these modalities with the potential for synergy."
Stroke patients and their loved ones must understand, however, that there must be sufficient residual motor power in their arm and hand to initiate some movement for this therapy to work, said Rashbaum, who is also clinical associate professor of rehabilitation medicine at New York University School of Medicine.
This robotic project has been presented at the American Stroke Association's International Stroke Conference 2007 which was held on February 7-9, 2007 in San Francisco. Here is a link to another press release announcing this presentation, "HOWARD the robot lends a hand after stroke," which gives more details about the results obtained with the patients during the study.
Sources: University of California - Irvine, February 8, 2007; and various other websites
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