By Robert Davis, USA TODAY
When her doctors first called her "The Bionic Woman," 26-year-old
Claudia Mitchell didn't understand the reference to the 1970s TV show
about the secret agent who was part woman, part machine.
Besides, the first woman to be outfitted with a bionic arm says that
when the motors are running in the 10-pound device, it reminds her of
another famous cyborg -- Arnold Schwarzenegger's The Terminator.
"It's really cool," she says. "This is not just something in the
movies. This is really happening." Mitchell, a former U.S. Marine,
lost her left arm in 2004 on an Arkansas highway when the friend she
was riding with lost control of his motorcycle.
As she struggled to cope with the loss of the limb, she read a Popular
Science story about Jesse Sullivan, a Tennessee man who received the
first bionic arms at the Rehabilitation Institute of Chicago after
losing his in an electrical accident in 2001.
"I said, 'I've got to have one of those,' " Mitchell says.
Last year she had surgery and received an arm that's even more
advanced than Sullivan's. Today, in a Washington, D.C., news
conference with National Institutes of Health officials, Mitchell will
show off her skills with the arm developed in a $4 million project
funded largely by the NIH.
Though recent prosthetic research has focused on implanting sensors
that link devices to movement commands from the brain, Mitchell was
drawn to the less-invasive work in Chicago.
"Most people have been looking at trying to tap into the brain, but
that has a number of challenges," says Todd Kuiken, who heads neural
engineering at the Chicago institute. Implants are "becoming more
doable, but if something breaks you have to have surgery to fix
it. The exciting thing about this technique is we are not implanting
anything into her body."
Kuiken found a way to use chest muscles to connect the prosthetic to
nerves that once sent signals to the hand, wrist, elbow and shoulder.
After an amputation, the brain still thinks the arm is there. It feels
sensations and sends signals to move. But those signals are too weak
for modern mechanics to detect from the surface of the skin, so
Kuiken's team amplified them.
First, plastic surgeon Greg Dumanian of Northwestern Memorial Hospital
moved the targeted nerves into muscles in Mitchell's chest. Then, the
nerves that cause the motion of those muscles were disconnected.
Mitchell can no longer send a signal to flex her pectoral muscle, but
when she wants to close her hand or bend her elbow, the nerve impulse
moves her "pec."
When that muscle moves, it sends a signal strong enough for a sensor
on the skin to detect. After some rewiring by Dumanian, six muscles in
Mitchell's chest now move six motors in the bionic arm.
And nerve data flow up, too. When Kuiken touches a certain spot on
Mitchell's chest, she feels him touch her hand, even though it's no
longer there.
There is much still to sort out. Though Mitchell can perform a simple
task such as folding a pair of pants without first stretching them out
on a flat surface, Kuiken calls the arm clumsy. Both he and Mitchell
say they are optimistic about making the prosthetic -- hers and future
versions -- more sensitive and precise.
"We hope to be able to close the loop with Claudia and have the
sensation be there so that when she touches something, she feels a
touch of her hand," Kuiken says. Mitchell, who hopes to go to college
next year to study communications, says she is proud to be part of the
team. "I am really excited about the prospects of being able to,
hopefully, pave the way to make this something that is more common,"
says Mitchell, a volunteer at Washington, D.C.-area military
hospitals.
Until today, her role in the bionic research project has been shrouded
in secrecy. But now, the former Marine who served in Kuwait can tell
the amputees she counsels about her arm and the research.
And some soldiers and Marines can now apply to follow Mitchell's lead.
Kuiken is looking for amputees who have lost arms above the elbow in
the past year.
Mitchell says some of the returnees she meets may be candidates. "I
have met these young women and men who are now changed forever," she
says. "I see how they are coping with life and how they are learning
to deal with their prosthesis. I know how they're feeling."
Some day, she says, the bionic arm may make it easier for amputees to
strap on a prosthesis and get on with their daily routines.
"I can open a spaghetti jar and hold it up at an angle and use a spoon
to empty it out," she says. "Small things like that may seem trivial
to a two-armed person, but it is very exciting to me."
Copyright 2006 USA TODAY, a division of Gannett Co. Inc.
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Robert Davis (usatoday@telecom-digest.org)