antiquity
01-09-2003, 01:05 PM
Jan. 8, 2003, 8:14PM
Tiny device helps ward off muscle atrophy
By LINDA MARSA
Los Angeles Times
It sounds like one of those fitness products peddled in late-night infomercials: an implantable stimulator that electrically exercises muscles. But if tests prove it effective, this miniature device could revolutionize the treatment of strokes and spinal cord injuries.
In these conditions, nerve signals that spark normal muscle function are blocked, causing paralysis. Over time, unused muscles atrophy, which can make rehabilitation and recovery more difficult. The new device, called a BION because it works like a bionic neuron, strengthens and retrains these muscles by mimicking the nerve impulses from the brain.
Scientists know electricity can be used to activate nerves and muscles throughout the body, said Dr. Gerald Loeb, a biomedical engineer who invented the muscle stimulator at the University of Southern California's Alfred E. Mann Institute for Biomedical Engineering. "But the trick was to create something that worked inside the muscle without leaving wires dangling through the skin."
Encapsulated in glass with electrodes at each end, the tiny device (the size of two grains of rice) is injected with a large needle into the "motor spot" -- the place where nerve endings meet muscle. When the muscles are ready to be exercised, a magnetic transmitter coil is placed over that part of the body. The coil sends power and command signals to the implant, prompting it to emit electrical pulses that activate the muscles.
"This is a real advance over what we have to treat people with severe muscle weakness," said Dr. Stephen D. Bagg, a stroke specialist at Queen's University in Canada who has studied the device. Because it could be used at home, it is expected to be more convenient and produce better patient compliance. Although the technology won't make anyone buff, it can reverse muscle atrophy, strengthen joints and enhance flexibility.
Therapeutic muscle stimulation is already used as part of physical therapy in patients who have sustained nerve damage. But current methods have drawbacks that limit their use.
The more common treatment is an electrical stimulator used on the surface of the skin. However, the electrical jolts can be painful, too high a charge can burn the skin, and the impulses may not hit the muscle in the right place. On the other hand, devices inserted directly into the muscles have to be surgically implanted, with electrical leads protruding through the skin, increasing risks of infection and breakage.
The new device seems to be just as effective, without these disadvantages. The first human tests of the bionic nerve began in 1999 in Canada, when the device was inserted into the shoulder muscles of 11 people who had recently suffered a stroke. The shoulder is a shallow joint and is held together by the activity of the muscles. When the muscles are flaccid, the weight of the muscles and the bone pulls the arm out of its socket, a painful shoulder dislocation that afflicts many stroke victims.
The study volunteers used the device, which can send up to 3,000 commands per second, at home for 20 to 30 minutes two to three times a day. At the end of six weeks, X-rays revealed the therapy had strengthened muscles and that the shoulder joint either remained aligned or, if it had already slipped out of place, had returned to its normal position.
Italian researchers have also tested the bionic nerve on patients with osteoarthritis in their knees. Because sufferers avoid bending their knees because of the arthritis pain, the muscles often atrophy. In that 12-week study, the volunteers experienced a significant reduction in pain and disability, Loeb said.
http://www.chron.com/cs/CDA/story.hts/health/1727874
Tiny device helps ward off muscle atrophy
By LINDA MARSA
Los Angeles Times
It sounds like one of those fitness products peddled in late-night infomercials: an implantable stimulator that electrically exercises muscles. But if tests prove it effective, this miniature device could revolutionize the treatment of strokes and spinal cord injuries.
In these conditions, nerve signals that spark normal muscle function are blocked, causing paralysis. Over time, unused muscles atrophy, which can make rehabilitation and recovery more difficult. The new device, called a BION because it works like a bionic neuron, strengthens and retrains these muscles by mimicking the nerve impulses from the brain.
Scientists know electricity can be used to activate nerves and muscles throughout the body, said Dr. Gerald Loeb, a biomedical engineer who invented the muscle stimulator at the University of Southern California's Alfred E. Mann Institute for Biomedical Engineering. "But the trick was to create something that worked inside the muscle without leaving wires dangling through the skin."
Encapsulated in glass with electrodes at each end, the tiny device (the size of two grains of rice) is injected with a large needle into the "motor spot" -- the place where nerve endings meet muscle. When the muscles are ready to be exercised, a magnetic transmitter coil is placed over that part of the body. The coil sends power and command signals to the implant, prompting it to emit electrical pulses that activate the muscles.
"This is a real advance over what we have to treat people with severe muscle weakness," said Dr. Stephen D. Bagg, a stroke specialist at Queen's University in Canada who has studied the device. Because it could be used at home, it is expected to be more convenient and produce better patient compliance. Although the technology won't make anyone buff, it can reverse muscle atrophy, strengthen joints and enhance flexibility.
Therapeutic muscle stimulation is already used as part of physical therapy in patients who have sustained nerve damage. But current methods have drawbacks that limit their use.
The more common treatment is an electrical stimulator used on the surface of the skin. However, the electrical jolts can be painful, too high a charge can burn the skin, and the impulses may not hit the muscle in the right place. On the other hand, devices inserted directly into the muscles have to be surgically implanted, with electrical leads protruding through the skin, increasing risks of infection and breakage.
The new device seems to be just as effective, without these disadvantages. The first human tests of the bionic nerve began in 1999 in Canada, when the device was inserted into the shoulder muscles of 11 people who had recently suffered a stroke. The shoulder is a shallow joint and is held together by the activity of the muscles. When the muscles are flaccid, the weight of the muscles and the bone pulls the arm out of its socket, a painful shoulder dislocation that afflicts many stroke victims.
The study volunteers used the device, which can send up to 3,000 commands per second, at home for 20 to 30 minutes two to three times a day. At the end of six weeks, X-rays revealed the therapy had strengthened muscles and that the shoulder joint either remained aligned or, if it had already slipped out of place, had returned to its normal position.
Italian researchers have also tested the bionic nerve on patients with osteoarthritis in their knees. Because sufferers avoid bending their knees because of the arthritis pain, the muscles often atrophy. In that 12-week study, the volunteers experienced a significant reduction in pain and disability, Loeb said.
http://www.chron.com/cs/CDA/story.hts/health/1727874