Lab pioneering arms controlled by thought

Pentagon taps APL to create prosthetics for amputee soldiers


The Pentagon wants to get one thing straight: It is not building a "bionic" arm like the one test pilot Steve Austin got in The Six Million Dollar Man TV series more than 30 years ago.

True, the government is paying the Johns Hopkins Applied Physics Laboratory $30.4 million to spearhead development of a thought-controlled mechanical arm for the growing number of soldiers who lose their own in battle or accidents.

But the new device won't give wearers super powers to carry back into combat. The APL's mission is to replace missing limbs with natural-looking arms and hands that soldiers can "feel" and operate with their brains, just like the real thing.

"We're not trying to improve the capability. We're restoring function," says Stuart D. Harshbarger, project manager for the APL. "It's more than just a little challenge - it's hard to top the human limb."

But it's worth the attempt. "A lot of these folks are still in their 20s. They have a lot of life ahead of them. ... They [the Pentagon] felt it was important to do whatever is possible to give them back a full range of abilities," Harshbarger said.

Although it sounds like science fiction, team members have already taught a mechanical hand to play rock-paper-scissors. And a Tennessee amputee managed to wreck a prototype thought-controlled arm trying to pull-start his lawnmower. So engineers know the concept works.

To move it to reality, the Defense Advanced Research Projects Agency (DARPA) has broken the job into two parts. The APL, based near Laurel, hopes to have the arm's thought-control and sensor systems ready for clinical trials in four years with an international team of 30 corporate, government and academic partners.

In a parallel, two-year effort under an $18.1 million contract, DEKA Research and Development Corp. of Manchester, N.H., will lead a team developing the arm's mechanical and cosmetic components.

The target price for the final product is $30,000 to $50,000 a copy. "It's going to cost about the same as a new car, to be honest," Harshbarger says.

There's a growing market for these sci-fi prosthetics - a result of improved body armor and prompt battlefield medical care in Iraq and Afghanistan. They save soldiers who would have died in past wars - but more of those are amputees.

Through January, the Pentagon says, 387 military personnel from the two conflicts had been treated at Army hospitals for the loss of hands, feet, arms or legs. Some are multiple amputees.

"We suddenly found ourselves with a number of young Americans who are badly injured and didn't have the prostheses they would need, or we would want them to have, in an ideal world," said Col. Geoffrey S.F. Ling, a physician and veteran of Iraq and Afghanistan who manages the program for DARPA.

"What's available commercially is woefully inadequate," he says. "We also set the bar really high. We want to give them back their lives."

The APL, best known for developing classified weapons for the military and interplanetary missions for NASA, may seem an unlikely candidate for this work. But over the years it has developed expertise in miniaturization and the abilities to extract weak signals from noisy environments and build sophisticated guidance systems - all valuable in building a high-tech arm.

Nor is the APL a stranger to prosthetics. In decades past, it helped develop rechargeable, motor-driven prosthetic arms for amputees who had difficulty using older, body-powered models. It also built a tabletop mechanical arm to spoon-feed paralyzed patients.

To carry out the current project, called the Revolutionizing Prosthetics Program, the lab will have to outdo its earlier efforts. "Even for DARPA, this is a significant challenge," Harshbarger said.

DARPA sponsors the Defense Department's cutting-edge scientific research. That means it puts big money (the Bush administration wants $2.9 billion next year) into projects with the highest risk of failure but the greatest potential payoff.

"DARPA-hard," they call it - projects that are technologically challenging, hard to administer or just too fantastic to attract a critical mass of private money and brainpower. Some DARPA successes: the Internet and the Global Positioning System.

When the prosthetic arm project came up, Harshbarger recalls, APL Director Richard Roca said that the lab had managed complex missions to Pluto and Mercury but quipped, "I'm not sure you guys can do this."

Modern, computerized prosthetic "C-legs" have enabled soldiers to walk normally and return to duty - even as paratroopers. But the arm and hand are far more complex, scientists say. And while today's best prosthetics offer amputees more than simple hooks or cosmetic hands, they're still far from ideal.

For example, a German company called Otto-Bock Healthcare (a partner in the new project) makes a three-fingered hand with a simple pinch grasp. The wrist can rotate, and the elbow can open and close.

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