New Technology May Boost Artificial Arms

TUESDAY, Feb. 10 (HealthDay News) -- Artificial arms are clunky, and many amputation patients don't even bother to use them because they're difficult to control.

But new research suggests that relocated nerves are allowing the brain to communicate directly with artificial arms, allowing patients to do things like peel a banana and fold laundry.

"In the simplest terms, it's a better tool," said study lead author Dr. Todd A. Kuiken, director of the Neural Engineering Center for Artificial Limbs at the Rehabilitation Institute of Chicago. "This will hopefully enable [patients] to do more of the everyday things that we all take for granted, be it cooking or cleaning or working in the yard."

The new artificial-arm technology is still in the development stages, and it will be years before it's improved enough for general use, Kuiken said. And artificial arms remain very expensive. Still, learning to better connect the brain to the arm through nerves is a big advance, he said.

Currently, people with arm amputations typically control their artificial limbs by tensing the muscles in their upper body, such as the biceps and triceps, to control cables, Kuiken said. But, many patients simply don't bother with the limbs, he said.

"The devices just aren't good enough to meet their needs," he said. "Control is a big issue."

In the new study, Kuiken and his colleagues tested a new strategy: surgically transferring the remaining nerves in the amputated arm to muscles in the chest and upper arm. The nerves then allow electrical signals to more easily reach the artificial arm with the help of a computer.

Between January 2007 and January 2008, the study authors compared five amputation patients who had undergone the surgery to five "control" subjects who did not have an amputation.

The researchers found that the patients who had undergone the surgery were able to move their elbows and wrists almost as fast as the other participants.

Essentially, the technology allows greater control of the arm by decoding the signals sent by the muscles, Kuiken said. You could think, "bend your wrist," and your wrist bends. You could think, "rotate your wrist," and your wrist rotates."

The potential cost of the surgery and related expenses is unclear. Currently, artificial arms can cost between $60,000 and $100,000, Kuiken said.

The study was published in the Feb. 11 issue of the Journal of the American Medical Association.

Dr. Gerald E. Loeb, director of the University of Southern California's Medical Device Development Facility, was impressed by the study results but cautioned that more work is needed.

"The Luke Skywalker [prosthetic] hand idea that's been in science fiction will require a lot of technology to come together," said Loeb, who wrote a commentary in the journal accompanying the study. "We're starting to see substantial advances in several of the pieces, but it's going to be a very long process to integrate these pieces into products for patients."

More information

Learn more about artificial limbs from reachoutmichigan.org.

SOURCES: Todd A. Kuiken, M.D., Ph.D., director, Neural Engineering Center for Artificial Limbs, Rehabilitation Institute of Chicago; Gerald E. Loeb, M.D., director, Medical Device Development Facility, University of Southern California, Los Angeles. Feb. 11, 2009, Journal of the American Medical Association

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