[AMP-L] Arm Amputee Uses Mind To Control Movement
wayne at renardson.org
Sun Aug 13 19:06:15 PDT 2006
Dayton, TN is the home of the infamous Scopes 'monkey' trial.
DAYTON, Tenn. - Jesse Sullivan has two prosthetic arms, but he has
no problem climbing a ladder at his house and rolling on a fresh coat
Sullivan's also good with a weed trimmer, bending his elbow and
rotating his forearm to guide the machine. His motions are
coordinated and smooth because one of his artificial arms is a bionic
device controlled by his brain. He thinks, "Close hand," and
electrical signals make it happen. Doctors describe Sullivan as the
first amputee with a thought-controlled artificial arm. Millions were
spent on the technology, and a researcher says the retail price would
be about $100,000 for a pair.
But doctors have asked Sullivan not to pamper the arms. "They said,
'Don't bring it back looking new,' " Sullivan said with a grin, his
brow showing sweat beneath a fraying Dollywood amusement park cap.
Most artificial arms today aren't much better than the clumsy wooden
prosthetics from a century ago. Artificial legs are simpler, but it
has been nearly impossible to recreate the subtle and complex motion
of a human arm.
Sullivan's prosthetic right arm is relatively simple, a motor-
operated limb with a hook. But his thought-controlled bionic arm
represents a real advance. The U.S. government, spurred by the
growing count of soldiers who have lost limbs in Iraq and
Afghanistan, is spending millions of dollars and working with
universities and private companies to develop artificial limbs that
connect body and mind.
Sullivan said he's proud to test the bionic arm for such soldiers.
"Those guys are heroes in my book, and they should have the best
there is," Sullivan said. "Hopefully they have got 60 or 70 years in
front of them."
The military's research-and-development wing - known as the Defense
Advanced Research Projects Agency, or DARPA - wants to develop a
mechanical arm that mimics the real thing by 2009.
DARPA gave The Johns Hopkins University Applied Physics Laboratory in
Laurel, Md., a $30.4 million contract to start the first phase of the
Sullivan lost his arms in May 2001 working as a utility lineman. He
suffered electrical burns so severe that doctors had to amputate both
his arms at the shoulder. Seven weeks later, Sullivan was in the
hands of Chicago researchers connected to the DARPA project.
Sullivan says his bionic arm isn't much like that depicted in the
'70s TV series "The Six Million Dollar Man." "I don't really feel
superhuman or anything," he said.
"Muscle reinnervation" is key to the bionic arm. For Sullivan, it
involved grafting shoulder nerves to his pectoral muscle. The grafts
receive thought-generated impulses to move the left arm and hand,
just as a normal arm would.
"The nerves grow into the chest muscles, so when the patient thinks,
'Close hand,' a portion of the chest muscle contracts," according to
an institute fact sheet.
Sullivan said his bionic arm allows him to rotate his upper arm, bend
his elbow, rotate his wrist, and open and close his hand, and make
some of those movements simultaneously.
There's still no sense of touch, but researchers are working to
change that. Sullivan said sometimes he's so rough with the bionic
arm around the house that it has broken, including once when he
pulled its end off starting a lawn mower. That prompted researchers
to make changes that have improved it, he said.
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