New Prosthetic Arm Technology Is Great News For Soldier Amputees

October 25, 2007

Randy Campbell, who lost an arm in an accident, uses a drill with a new prosthetic arm during a demonstration Oct. 17. With one kind of prosthetic arm, patients wear electrodes attached to nerves — transferred from the arm to the chest. When the patient thinks to move the arm, the brain tells the nerve, and the electrode on top of the nerve tells the arm what to do.

No, this isn’t reruns of Wonder Woman or the Six Million Dollar Man, instead it’s the government’s latest research into making better prosthetics for amputees who have lost an arm in the war, or even in an accident of some kind. Many of our Wounded Warriors have not only lost legs, fighting in the Global War on Terror, have also lost arms. While the advances in technology for prosthetic legs are phenomenal, the advances haven’t been so quick in coming for prosthetic arms. Many rely on non-moving prosthetic hands or hooks. Now however, things are beginning to move forward.

On October 17th, former Marine Cpl. Claudia Mitchell and others were part of a demonstration of cutting-edge technology in the field of arm prosthetics that was presented by the Defense Advanced Research Projects Agency(DARPA). The goal is that within the next two years, to have perfected an arm that has neural control. Mitchell demonstrated are “bionic arm” With a neral sensor on her chest, along with an advanced mechanical arm and hand. This gives her a far greater range of movement than is possible with the current prosthetic arms and hooks. Now when she thinks about bending her arm, it happens. She now has a much further range of motion then she did when she had the prosthesis with a hook.

“I don’t have to think of the entire sequence of movements,” she said. With the new technology, her thoughts control her nerves and her nervees control the movement of the arm.

“The hand can close in different ways,” Mitchell said.

Mitchell lost her arm in a motorcycle accident in May 2004, shortly after she left the Marine Corps. The “bionic” arm is much more comfortable than the current prosthetics or hooks. She says that at times she’s done things like crossed her arms, things that for someone with both arms, is a very natural movement and didn’t even realize she was doing it with her bionic arm. Mitchell is one of several who are helping to test the arm, which was developed by John Hopkins University Applied Physics Lab, which is leading an international team of researchers in work that could have a profound effect on amputees.

“They train the arm to understand whit it is that I want to do,” Mitchell said.

In Mitchell’s case the peripheral nerves that remained just above where her arm were amputated were transferred to her chest. She wears electrodes on the top of those nerves. When she thinks of making a movement, the brain then signals those nerves. The electrodes on top of the nevers tells the arm what to do. A device may also be implanted into the pectoral muscles of the chest.

The idea is to provide even greater control over the prosthetic, by using a microchip that’s about the size of a fingernail. That electrode would be implanted on the surface of the brain, according to Army Col. Geoffrey Ling, who is the program manager of DARPA’s Revolutionizing Prosthetics initiative.

This would allow the amputee even greater flexibility, perhaps to play the piano or write with the prosthetic, by tapping into the nervous system. According to Ling, primates now testing prosthetic arms are now feeding themselves.

The goal is to develop a prosthetic arm that will be able to function as well as a normal human arm, with the same strength and dexterity. The hopes are to provide the ability to sense touch, temperature, vibration, arm and hand position in relation to other parts of the body, as well as provide a power source for the arm that will allow at least 24 hours of normal use.

Prosthetics for amputated upper limbs have not advanced near as quickly as lower limb prosthetics. With this research, the hopes are, that that will quickly change. The mechanical components of the arms will be able to withstand heat, cold, water, humidity, dust and other elements that are found in everyday life. The prosthetic will last at least 10 years with normal use.

Retired Marine Captain Jonathan Kuniholm is an engineer at Duke University who is doing research on “grasp control” software for the prosthetic arm. He is interested in signal analysis and control of the hand, which will allow the user to do things like pinching. His work, is part of the John Hopkins project. He is also helping test the arms, as he lost one of his own to a roadside bom in Iraq on New Year’s Day 2005. According to Ling, about 300 service members have lost arms.

“Most have the hook,” he said. “It’s the best available.”

With the hook type arm, all the person can do is open and close the hook to grasp onto things. With the new technology, the hope is to have an arm which will have 24 different directional movements.

In the meantime, an arm that has been developed is superior to the hook. This arm allows the person to feed and groom themselves. It only requires a couple of hours of training.

Randy Campbell, who lost his arm in an accident in 2004, is participating in the clinical trials of the arm developed by DEKA Research who is also part of the research through DARPA. Their work will wrap up this winter and then they will move on to the next phase, which includes approval from FAD. If approved, this will allow servicemembers as well as other amputees, many more options than the hook. Campbell demonstrated the arm by picking up a power drill and drilling a hole and then screwing a screw into a piece of wood. Using the prosthetic, he was also able to pick up Skittles from a surface, with his fingers and then eat it, though it did take him a couple of attempts.

This is great news and looks to be very promising. I’m sure that many upper limb amputees are looking forward to these arms being approved by the FDA and made available to them. With all the advances in lower amputation limbs, it’s great to see the same technology and research being applied to improving prosthetic arms for those who have lost their arms. Having a prosthetic arm with this range of motion and ability to move, will allow those servicemembers who have lost an arm in the Global War on Terror, the option of remaining active duty, as some of their peers who have lost their legs, are doing.

Army Times

Written by Terri · Filed Under PTSD, Traumatic Brain Injury, Military Medical Issues

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