Via two tiny electrode arrays put in her brain, Scheuermann uses her mind to control a robotic arm.
UPMC
By late January of this year, there had been 1,585 amputations involving troops who’d served in Afghanistan or Iraq. Of those, nearly one in five involved a portion of the arm or hand, according to Department of Defense statistics. Unfortunately, existing arm and hand prostheses are typically cruder and less functional than those available for legs, says Dr. Geoffrey Ling, deputy director for DARPA’s Defense Sciences Office and program manager for Revolutionizing Prosthetics. That’s because of nature’s ­engineering; there are far more joint movements in the wrist and hand to replicate than in the leg. But Ling, a neuro-critical-care physician who retired as an Army colonel in 2012 after combat tours in Afghanistan and Iraq, is undaunted. “At DARPA, we don’t believe in anything that’s insurmountable,” he explains, with a touch of braggadocio.

Launched in 2006, Revolutionizing Prosthetics has been funded to the tune of $144 million to date and involves numerous medical centers and researchers. (DARPA estimated having more than 300 researchers in 2010, but officials didn’t venture a more recent figure.) And though it’s only been seven years, amputee patients, veterans and civilians alike are starting to benefit from the program’s advances in treatment.

For example, some amputees are taking advantage of a surgical technique called targeted muscle reinnervation that allows them to use remaining nerves to exert better control over a prosthesis. During the surgical procedure, the nerves are transferred into muscle tissue, enabling more natural movement. And by the time you read this, perhaps federal officials will have approved the commercial sale of another key Revolutionizing Prosthetics effort — the creation of a sophisticated motorized arm for mobile amputee patients. Called the DEKA Gen-3 Arm System, it’s considered a substantial improvement over more traditional, griplike prosthetic devices.

Dr. Justin Greisberg, associate professor of clinical orthopedic surgery at Columbia University Medical Center in New York, has been following these advances and tells patients that the evolving technology’s potential is enormous in terms of improving quality of life.

“It’s going to take some time and some work,” he says. “But it’s not if we’re getting a much more functional robotic arm — it’s just a matter of when.”

STRETCHING FROM THE SHOULDER to the fingertips, the human arm easily executes a daunting spectrum of bioengineering capabilities each day — lifting a gallon of milk, eating grapes, grasping and turning a doorknob. The arm is capable of 29 degrees of motion. (Actually, more: A simple joint movement, such as flexing the elbow open and closed, is considered one degree.)

While prosthetic arms and hands are improving, until recent years, they’ve been largely limited to griplike hands that only open and close, says Linda Resnik, a research health scientist at the Providence Veterans Affairs Medical Center in Rhode Island. Sometimes people will give up entirely, particularly if the prosthesis replaces a large portion of an arm. “They may be uncomfortable to wear,” she says, “and they don’t feel like they’re really that beneficial in helping them do more.”