Researchers making strides on prosthetic arms for vets

Fred Downs waited 46 years for that drink.

It was just water, but it was the first time he was able to pick up a bottle with his left hand in 46 years, since losing it in the Vietnam War as a 23-year-old company commander.

{mosads}“The first time I was able to use this left arm to drink out of a bottle — it was emotional,” he said.

Thanks to new and improving technology, Downs now has a prosthetic arm that can grip things, something that he has not been able to do since losing his arm to a mine.

“In a way, it improves your self-worth. I’m able to do more. It’s exciting to be able to figure out new things to do,” Downs said.

“I’m learning new things every day: how to hold things, pour things, grab things out of the refrigerator, when I’m doing the laundry, holding the bleach cup … the kinds of normal things you don’t even think about,” he said.

Down’s prosthetic arm is produced by Deka Research and Development Corp. and is revolutionary due to its ability to grip, something that his prosthetic hook couldn’t do.

“The ability to grasp, and to pinch and to hold, can make major differences in your life,” Downs said. “It’s the little things.”

There are 10 separate motors in the arm driving the wrist and fingers, according to Tom Doyon, the lead electrical engineer for Deka’s robotic arm program. 

The prosthetic is covered by a thin, clear layer of rubber, but it is shaped and sized like a human arm and controlled by wireless sensors attached to both feet.
If Downs moves his foot sideways, for instance, his wrist will turn accordingly. He can put the arm on stand-by mode when walking.

Downs attaches it in the morning and takes it off before sleeping.

“It’s so neat — it really works! It’s solid, it’s tough, and it gives me confidence. All those things have affected me psychologically. I’m always happy when I’m able to do things myself,” Downs said.

Downs’s new arm is still a trial version, though it has just been approved by the Food and Drug Administration and will soon be available commercially. The program began in 2006.

Downs said once it’s available commercially, he said he will go to the Department of Veterans Affairs and request one permanently.

Prosthetics technology has advanced quickly in recent years due to the wars in Iraq and Afghanistan. Veterans with prosthetic legs have become a common sight around military bases due to the proliferation of improvised explosive devices that often strike vehicle conveys. 

Progress on arm prosthetics has trailed that of leg prosthetics, however, because the majority of veterans’ amputations have been their lower extremities.

Only about 300 Iraq and Afghanistan war veterans are upper extremity amputees, according to Michael P. McLoughlin, chief engineer for research and exploratory development for Johns Hopkins University’s Applied Physics Laboratory (APL).
 
The APL is developing a different arm, controlled by brain neuron activity converted to robotic arm motion via brain chip implants or external sensors that pick up brain waves.

The technology allows a user to move a robotic arm by thinking about it.
The lab’s arm is further behind Deka’s program, but it is intended for the future, whereas Deka’s arm is intended for near-term use, McLoughlin said.

The APL’s arm has 26 joints and, like Deka’s, is the same shape and size as an average arm. In the future, it might be able to type on a computer and function just like a natural limb, McLoughlin said.

“It can curl 45 pounds. It has a pinch-grip of 20 pounds, so it’s the closest thing in existence to what a human arm can do,” McLoughlin. “It also has a whole lot of sensors on it, so that as it touches an object, it can detect that, can measure pressure, surface texture.”

He said the next step is to be able to feed the information back to the brain.

“By stimulating the nerves, we can now produce sensation,” he said.

The Defense Advanced Research Projects Agency (DARPA), the Pentagon’s shop for developing cutting edge technologies, is helping to fund both programs in order to spur the robotic arm industry.

“Upper extremity prosthetics has not advanced as far as lower extremity prosthetics,” Doyon said. “Lower extremity prosthetics is a much less complicated problem to solve, because typically there is really just one joint involved whether it’s the ankle or the knee, so the industry took care of itself.”

“But because this is a much more difficult problem and costly problem to solve, it’s a good thing that DARPA got involved and funded this development effort,” said Doyon.

DARPA has invested $40 million into Deka’s program. Deka representatives said at this time, they do not have a cost figure for the arm.

Engineers hope that the robotic arm industry can grow due to the other applications it may serve.

For instance, robotic arms can be used in undersea applications such as explosive ordnance disposal, other military applications, manufacturing, or for home assistance, said McLoughlin.

However, he said there is no more important application than giving veterans back their functionality.
“These wounded kids, they got a lot of years ahead of them,” McLoughlin said. “It gives us a sense of urgency here. They want to get back and be productive.”

“To personally have seen the impact … it’s a very powerful moving experience for them, and it means a lot to them,” he said. “That’s what really keeps us all going on this. It’s been very exciting.”