Robotic Arm Holds Promise for Stroke Survivors

Arizona State University researchers and Tempe-based Kinetic Muscles, Inc., have developed a robotic arm to help stroke survivors regain the ability to perform basic tasks, such as reaching for objects or feeding themselves. The rehabilitative device aids in task-oriented repetitive therapy, and the hope is that it will provide a cost-effective alternative to traditional therapies. This would enable a larger percentage of patients to regain maximum motor function.

The research team is led by Jiping He, Ph.D., of the Biodesign Institute at Arizona State University. Dr. He directs the Institute’s Center for Neural Interface Design and is a professor of bioengineering at ASU’s Fulton School of Engineering. Dr. He will present a paper on the design and evaluation of the robotic arm this summer at the 9th International Conference on Rehabilitation Robotics in Chicago June 28-30, 2005.

The device is dubbed “RUPERT,” for Robotic Upper Extremity Repetitive Therapy. Kinetic Muscles, Inc. is producing the prototypes for the project, which is funded by the National Institutes of Health. Kinetic Muscles currently has a device for hand rehabilitation for stroke survivors on the market.

There are two key benefit phases for stroke victims in the project development timetable, according to Dr. He. Currently, the device is able to mimic a fluid, natural extension of the arm using pneumatic muscles and can be programmed for repetitive exercises specific to the user that improve arm and hand flexibility and strength.

The ASU research and development team includes the following faculty members: professors Don Herring of Industrial Design, Tom Sugar of Mechanical and Aerospace Engineering, and Thanassis Rikakis, Todd Ingalls and Loren Olson of Arts, Media and Engineering. In addition, graduate students Helen Huang of Bioengineering, John Wanburg of Industrial Design and Kartik Bharadwaj of Mechanical and Aerospace Engineering played fundamental roles in the progress of the project.

The team is now working to engineer greater intelligence into the device so that it responds directly to a user’s intent. “We want RUPERT to be able to sense when the user is attempting to reach for something and to automatically assist their volitional movement,” said Dr. He. “Not only is the goal to make the motion more intuitive, but we want the robot to assist at those points in the movement where the individual needs it,” said He. As the individual’s motor function improves, RUPERT would adapt to allow the user faster recovery by requiring the muscles to work independently where possible.

With “RUPERT 1″ in the foreground, Bruce, Janice and Ed Koeneman (COO of Kinetic Muscles Inc) go through lifting and bending exercises utilizing the newest prototype, “RUPERT 2″.The first RUPERT prototype was fitted and tested on able-bodied individuals and stroke survivors at Banner Good Samaritan Regional Medical Center in Phoenix. Eight able-bodied individuals tried on RUPERT I to see how well it could be adjusted to fit each in each case. The testers ranged from five-foot females to over-six-foot males. In addition, two stroke survivors completed a three-week course of therapy using the device. RUPERT II, a second generation prototype, is under development using results of the fitting evaluations and therapy testing at the medical center.

RUPERT I and II are powered by four pneumatic muscles to assist movement at the shoulder, elbow and wrist. The design was based on a kinematics model of the arm, which showed where to locate the pneumatic muscles and how much force was needed for normal reaching and feeding movements. The mechanical arm is adjustable to accommodate different arm lengths and body sizes.

Recent research suggests that stroke survivors can recover significant use of their arms by performing repetitive motor function exercises over a period of time. This labor-intensive physical therapy is expensive, however, claiming up to four percent of the national health budget, according to the National Institute of Health. Moreover, health insurers may limit or deny coverage before stroke survivors achieve best results, Dr. He said. The availability of a device like RUPERT, which could be used at home with greater frequency and for a longer period of time, may prove to be a more cost-effective approach that would provide better results.

Source: Arizona State University