SeaPlankton
October 22nd, 2006, 09:27 AM
http://www.theaustralian.news.com.au/story/0,20867,20416610-2703,00.html
Woman unveils brain-controlled bionic arm
Nigel Hawkes
September 15, 2006
CLAUDIA MITCHELL, a former US Marine who lost an arm in a motorcycle accident, is the first woman to be fitted with a new prosthetic arm controlled by her own nerves.
The night before she showed off the left arm at a news conference, she used it to cut a steak — the first she had been able to eat in a conventional way since her accident more than two years ago. “That was a very big thing for me,” she said.
High-tech prosthetic limbs have a chequered history. More often than not, patients fitted with them give up and revert to simple devices with a good appearance but little functionality. But engineers keep trying to achieve the ideal — a limb that is controlled by the brain and works well while looking near-normal.
Ms Mitchell, 26, is one of six people trying out the latest model, developed by the Rehabilitation Institute of Chicago. With her older prosthetic arm, she could do only one thing at a time — either open her elbow or open her hand. And to do so, she had to concentrate on a particular muscle.
“It was odd,” she said. “I had to think, ‘OK, my hand is here. Which muscle?’” She had to concentrate on flexing her pectoral muscle, or the triceps, to get the arms and hand to do what she wanted. “Now I just think about it.”
Like many amputees, she often left her old-fashioned artificial arm at home. “It just didn’t work well enough to bother wearing it,” she 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 little crude, as its developer, Todd Kuiken, admits. It weighs 11lb (5kg) and one motor extends far beyond her shoulder, with wires and mechanical parts, including some of the six motors, clearly visible. Her hand is covered with a flesh-colored sheath, and the fingers move awkwardly. But they do move.
What is unique about the new arm is the interface between body and machine. Dr Kuiken worked with Gregory Dumanian, a plastic surgeon, at Northwestern Memorial Hospital in Chicago to move the five nerves that once controlled her arm.
Dr Dumanian placed the ends of the nerves in her chest, where they regrew close to the skin. Electrodes placed on the surface of Ms 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 Kuiken said. When Ms Mitchell thinks about moving her hand or arm, the nerves fire 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.
___________________________
She said in a BBC interview it was great to be able to get coffee from the cupboard with her new clanky arm. Millions of macaque monkeys had to die in pain for a grunt to get her caffiene fix.
Woman unveils brain-controlled bionic arm
Nigel Hawkes
September 15, 2006
CLAUDIA MITCHELL, a former US Marine who lost an arm in a motorcycle accident, is the first woman to be fitted with a new prosthetic arm controlled by her own nerves.
The night before she showed off the left arm at a news conference, she used it to cut a steak — the first she had been able to eat in a conventional way since her accident more than two years ago. “That was a very big thing for me,” she said.
High-tech prosthetic limbs have a chequered history. More often than not, patients fitted with them give up and revert to simple devices with a good appearance but little functionality. But engineers keep trying to achieve the ideal — a limb that is controlled by the brain and works well while looking near-normal.
Ms Mitchell, 26, is one of six people trying out the latest model, developed by the Rehabilitation Institute of Chicago. With her older prosthetic arm, she could do only one thing at a time — either open her elbow or open her hand. And to do so, she had to concentrate on a particular muscle.
“It was odd,” she said. “I had to think, ‘OK, my hand is here. Which muscle?’” She had to concentrate on flexing her pectoral muscle, or the triceps, to get the arms and hand to do what she wanted. “Now I just think about it.”
Like many amputees, she often left her old-fashioned artificial arm at home. “It just didn’t work well enough to bother wearing it,” she 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 little crude, as its developer, Todd Kuiken, admits. It weighs 11lb (5kg) and one motor extends far beyond her shoulder, with wires and mechanical parts, including some of the six motors, clearly visible. Her hand is covered with a flesh-colored sheath, and the fingers move awkwardly. But they do move.
What is unique about the new arm is the interface between body and machine. Dr Kuiken worked with Gregory Dumanian, a plastic surgeon, at Northwestern Memorial Hospital in Chicago to move the five nerves that once controlled her arm.
Dr Dumanian placed the ends of the nerves in her chest, where they regrew close to the skin. Electrodes placed on the surface of Ms 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 Kuiken said. When Ms Mitchell thinks about moving her hand or arm, the nerves fire 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.
___________________________
She said in a BBC interview it was great to be able to get coffee from the cupboard with her new clanky arm. Millions of macaque monkeys had to die in pain for a grunt to get her caffiene fix.