'Bionic' Arms Give Amputees Freedom to Move
WASHINGTON -- The night before her big news conference, Claudia Mitchell cut a steak for the first time since she lost her left arm in a motorcycle accident more than two years ago - thanks to her "bionic" arm.
Mitchell, 26, is the first woman to be fitted with the experimental arm, which re-directs severed nerves to send her brain's signals to the electronic motors in the prosthetic.
ADVERTISEMENTShe is one of six people to try out the arm, being developed by the Rehabilitation Institute of Chicago.
With her older prosthetic arm, Mitchell could only do one thing at a time - either open her elbow or open her hand. "It was odd," Mitchell told a news conference. "I had to think, 'OK, my hand is here. Which muscle?'" She had to concentrate on flexing her pectoral muscle, or the triceps, to power the arm.
"Now I just think about it."
Like many amputees, Mitchell, a former Marine, often left her old-fashioned artificial arm at home.
"My other arm, it just didn't work well enough to bother wearing it," Mitchell said. "This might be bigger and feel a little awkward, but the amount of function that I get out of it makes it worth wearing it."
The device is "a tank," admits Dr. Todd Kuiken, its developer. It weighs 11 pounds and one motor extends far beyond her shoulder, with wires and mechanical parts, including some of the six motors, clearly visible.
The hand is covered with a flesh-colored sheath that resemble a rubber dishwashing glove, and the fingers move awkwardly. But they do move.
"Last night I cut my first steak since my amputation. That was a very big thing for me," Mitchell said.
WHERE FLESH MEETS MACHINE
What is unique about Mitchell's arm is the interface between body and machine.
Kuiken worked with plastic surgeon Dr. Gregory Dumanian at Chicago's Northwestern Memorial Hospital to move the five nerves that once controlled her arm, removed at the shoulder after Mitchell's accident.
Dumanian placed the ends of the nerves in her chest, where they re-grew close to the skin.
Electrodes placed on the surface of Mitchell's chest then send signals that control the arm.
"The brain doesn't know that these nerves are connected to different tissue or muscle," Dr. Todd Kuiken, director of amputee programs at the Institute and the arm's designer, told the news conference.
When Mitchell thinks about moving her hand or arm, the nerves fire just as if they were still leading all the way down her arm and into the elbow and fingers. The signals are picked up by the electrodes on her skin, which in turn send commands to the six motors in the electronic arm.
Her "take-home arm" has the electrodes in a plastic harness that fits over her shoulder and part of her chest. The "bionic" arm is far more fragile and so far can be only used in the lab at the Institute.
The next step is to have the signals come back the other way, from the fingers on the prosthetic to the nerves in the chest and then the brain, so that Mitchell can feel pressure, heat or cold, and even a sharp edge.
One hope is to perfect the arms for veterans who have lost limbs.
Other teams are working to develop ways to control prosthetic devices using thought alone, without surgery to re-direct nerves.
A team at Cyberkinetics Neurotechnology Systems Inc in Massachusetts have a chip that, implanted into a patient's brain, allows him to control a computer.
Teams at the University of Pittsburgh Medical Center and at Duke University have built arm devices that monkeys can power with their thoughts alone.
WASHINGTON -- The night before her big news conference, Claudia Mitchell cut a steak for the first time since she lost her left arm in a motorcycle accident more than two years ago - thanks to her "bionic" arm.
Mitchell, 26, is the first woman to be fitted with the experimental arm, which re-directs severed nerves to send her brain's signals to the electronic motors in the prosthetic.
ADVERTISEMENTShe is one of six people to try out the arm, being developed by the Rehabilitation Institute of Chicago.
With her older prosthetic arm, Mitchell could only do one thing at a time - either open her elbow or open her hand. "It was odd," Mitchell told a news conference. "I had to think, 'OK, my hand is here. Which muscle?'" She had to concentrate on flexing her pectoral muscle, or the triceps, to power the arm.
"Now I just think about it."
Like many amputees, Mitchell, a former Marine, often left her old-fashioned artificial arm at home.
"My other arm, it just didn't work well enough to bother wearing it," Mitchell said. "This might be bigger and feel a little awkward, but the amount of function that I get out of it makes it worth wearing it."
The device is "a tank," admits Dr. Todd Kuiken, its developer. It weighs 11 pounds and one motor extends far beyond her shoulder, with wires and mechanical parts, including some of the six motors, clearly visible.
The hand is covered with a flesh-colored sheath that resemble a rubber dishwashing glove, and the fingers move awkwardly. But they do move.
"Last night I cut my first steak since my amputation. That was a very big thing for me," Mitchell said.
WHERE FLESH MEETS MACHINE
What is unique about Mitchell's arm is the interface between body and machine.
Kuiken worked with plastic surgeon Dr. Gregory Dumanian at Chicago's Northwestern Memorial Hospital to move the five nerves that once controlled her arm, removed at the shoulder after Mitchell's accident.
Dumanian placed the ends of the nerves in her chest, where they re-grew close to the skin.
Electrodes placed on the surface of Mitchell's chest then send signals that control the arm.
"The brain doesn't know that these nerves are connected to different tissue or muscle," Dr. Todd Kuiken, director of amputee programs at the Institute and the arm's designer, told the news conference.
When Mitchell thinks about moving her hand or arm, the nerves fire just as if they were still leading all the way down her arm and into the elbow and fingers. The signals are picked up by the electrodes on her skin, which in turn send commands to the six motors in the electronic arm.
Her "take-home arm" has the electrodes in a plastic harness that fits over her shoulder and part of her chest. The "bionic" arm is far more fragile and so far can be only used in the lab at the Institute.
The next step is to have the signals come back the other way, from the fingers on the prosthetic to the nerves in the chest and then the brain, so that Mitchell can feel pressure, heat or cold, and even a sharp edge.
One hope is to perfect the arms for veterans who have lost limbs.
Other teams are working to develop ways to control prosthetic devices using thought alone, without surgery to re-direct nerves.
A team at Cyberkinetics Neurotechnology Systems Inc in Massachusetts have a chip that, implanted into a patient's brain, allows him to control a computer.
Teams at the University of Pittsburgh Medical Center and at Duke University have built arm devices that monkeys can power with their thoughts alone.
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