 Department of Veterans Affairs
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Rehabilitation Research in
Palo Alto
Center Concentrates on Mobility
by Patricia S. Forsyth
Since it opened in 1978, the VA Palo Alto Health Care System's Rehabilitation Research and Development Center has become well-known for innovative clinical treatments and technological devices for physically disabled veterans and the entire community.
Felix Zajac, PhD, is engineering and scientific director, Charles Burgar, MD, serves as medical director, and Dennis Carter, PhD, is associate director. Dr. Zajac has a strong interest in motor control research and Dr. Carter, a mechanical engineer, in how bone and cartilage change in response to stress, Dr. Burgar pointed out, while he himself is a clinician specializing in physical medicine and rehabilitation. "That sets the tone for what we do here," Dr. Burgar said.
Focus on Mobility
The center's overall focus is on mobility; especially how physical forces can he used to affect mobility in people who have been impaired by stroke, spinal cord injury, arthritis, osteoporosis, and other conditions. Basic research projects are underway to improve understanding of how the nervous system controls muscles and how gone grows and regenerates itself. Center researchers also collaborate closely with clinicians at the Palo Alto VA and Stanford University medical centers and other clinical centers. "This helps us ensure relevance of our research and clinically test our treatments and devices," Dr. Burgar noted.
One center project is designed to help post-stroke patients reduce the likelihood of falling as they regain coordination after a stroke by testing their ability to step over virtual" obstacles. The patient wears a visor-like device with a tiny TV screen built in to simulate negotiating a path with obstacles. "The advantage is that there is no fall if the patient fails to clear a virtual object," Dr. Burgar said. "This can he used for training and also as a test to see how well patients are learning." Physical therapist David A. Brown, PhD, and biomedical engineer David L. Jaffe, MS head the project.
Another project is a collaboration with the National Aeronautics and Space Administration. NASA has an obvious interest in the effect of micro gravity on exercise, Dr. Burgar pointed out. During space flight, astronauts experience declines in many body systems, including loss of bone strength. Because exercise may help maintain muscle and bone during space flight, a team led by NASA researcher Robert Whalen, PhD, has developed a system using an exercise treadmill, an acrylic tent-like device sealing the system around a user's waist and legs, and an ordinary industrial vacuum cleaner that uses suction as a substitute for gravity to hold the astronauts onto the tread as they walk.
"Of course that is not what I need when I get a patient newly out of bed," Dr. Burgar pointed out. "We decided if you can pull a person down with this device perhaps you can lift somebody up, and it turns out you can." By reversing the vacuum, researchers found they could apply enough pressure to lift people's weight off their feet. "It's like the machine is trying to spit them out the top like a champagne cork," Dr. Burgar said. "It simulates micro gravity, and we can make patients feel like they are walking on the moon."
Because the pressure can be controlled, he emphasized, each patient can bear as much weight as possible while walking, with the machine supplying the rest of the lift that traditionally must be provided by parallel bars or a therapist. "Using this device, we hope to be able to do gait training very early after a neurological injury, Dr. Burgar said.
Mechanical Manipulation
A student with a spinal cord injury uses a robot-equipped workstation in a desktop publishing course at the Rehabilitation Research and Development Center in Palo Alto. (Photo by Curt Campbell, VA Palo Alto Health Care System)
A common theme in many center projects is use of mechanical manipulation to restore or maintain muscle and bone function. By providing appropriate sensory input, the researchers can influence the way in which the nervous system reorganizes itself after injury. They are using mathematical computer models to help them understand complex neuromuscular systems. One project focuses on how muscles are activated. Using a pedaling device, the researchers can measure activation and how muscles work to achieve a particular motion. A bicycle-like device resulting from this project helps patients learn to walk again after neurological injury. In this project, led by Dr. Brown and Steven A. Kautz, PhD, the cycle can be rotated to different positions that allow a weak person to begin strengthening exercises lying down.
Another center project addresses the problem of upper limb strength after a stroke. For many stroke patients, losing the ability to drive decreases their quality of life. The Palo Alto researchers have developed techniques to measure how much force each hand provides to each side of a steering wheel and to train patients to use the weaker side more effectively. Michelle Johnson, MS, a doctoral candidate at Stanford, is working with center investigators on this project. To enhance rehabilitation training, the center is equipped with a gymnasium similar to standard physical therapy gyms and has a staff of physical and occupational therapists.
Another important facet of the center is its laboratory for testing the effects of different loads on actual bone or materials formulated to behave like bone. This laboratory, led by Dr. Carter and Gary Beaupré, PhD, is currently studying cartilage growth. A common "wear and tear" problem of aging is osteoarthritis resulting from breakdown of joint cartilage. Although recent studies elsewhere have shown that human cartilage cells can be grown in the laboratory and then reinserted in to arthritic joints, these laboratory-cultured cells may fail to produce the optimal kind of cartilage. Lane Smith, PhD, and colleagues are attempting to determine how cartilage-cell genes can be turned on to create the right type of cartilage. "We want to establish how genes in cartilage cells can be turned on to create the right kind of cartilage," Dr. Burgar said. "This is a bit more basic research than many of our center projects, but we expect it to end up in the clinics within five to ten years.
New Devices
The Handbike arm-powered bicycle is among the devices developed at the Rehabilitation Research and Development Center in Palo Alto. (Photo by Curt Campbell, VA Palo Alto Health Care System)
A major focus of the center is in development of devices that supplement research aims of other projects or that may directly benefit patients. One such device, is a hand bike designed for people with lower limb disability. All power, steering, and braking done by hand. This effort initially was a student project in the Stanford design division of mechanical engineering, Dr. Burgar noted. The bike, which is now commercially available, began as a project by Stanford mechanical engineering student Doug Schwandt, MS who continued its development at the Rehab R&D Center.
Another device is the head-controlled wheelchair developed by biomedical engineer David L. Jaffe. The chair uses ultrasound and allows users to steer by leaning their heads. Other examples of products developed at the center that have been brought to market to benefit veterans and others with disabilities include the Handtyper, a sturdy, lightweight typing aid for persons with limited hand function, developed by a team led by occupation therapist Stephanie O'Leary. The Lingraphica portable assistive and therapeutic communications device for people with aphasia from stroke or other brain injury was designed by Richard Steele, PhD, and colleagues. Kevin McGill, PhD, developed a computer program for analyzing clinical electromyograms.
Another center innovation is a program focusing on techniques to help disabled people go back to work, such as the use of robots as work station assistants for quadriplegics. Using this and similar devices, Machiel Van der Loos, PhD, has developed courses for desktop publishing and related skills. "Most of our students had no computer skills when they came in," Dr. Burgar said, "but most found employment. In fact, we hired one of these students ourselves."