Magical Mind-Controlled Limbs  

Six years ago the American military sought to change the outdated prosthetics industry with infusion of cash. The resulting devices are stunning, but can they change the lives of amputees? 

There is a video that made the rounds of medical conferences in 2009. It begins with Fred Downs, a gruff four-time Purple Heart awardee and the head of the Department of Veterans Affairs prosthetic program, demonstrating the hook he’s worn strapped to his left shoulder for the last 40-years, ever since he lost his arm in Vietnam.  The hook looks just like you’d expect – the spitting image of Captain Hook’s cruel pirate arm: curved steel screwed to a varnished wood stump. It’s not so bad, explains Downs, as he hooks a soda and drags it across a table toward his real arm.

If the hook is a relic of medieval times the next scene flashes straight to the age of enlightenment. Downs has been fitted into the “Luke” arm, a shiny, state-of-the-art mechanical limb (named for Luke Skywalker) that’s been surgically attached to his shoulder, allowing the device to sense the electronic impulses of his remaining nerves and move in concordance. Downs tests out the arm, bending it at the elbow and giving a thumbs-up. He fans the fingers.  He plucks a grape from a bunch. He grips a bottle of soda and brings it to his mouth.  He chokes up.

The stoic soldier has started to cry. “It feels so good to move my arm again,” mumbles Downs.

For half-a-century prosthetic technology has evolved only slightly beyond the hook – for reasons both technical and practical. Creating the motion and control of a limb is a wild project and research is largely built on the simple, easy to maintain products that fuel the $3.1 billion dollar prosthetics industry. But development of upper-body devices has lagged even more significantly behind prosthetics for the lower body because of the impossibility of re-creating an arm. Arms and hands, which have to bend and flex and lift and grip in a myriad of ways, are much more complicated than legs, which mostly just support weight.

But in 2006 a little-known branch of the Department of Defense set out to change the state of things with an impossible task: create the perfect prosthetic arm. The Defense Advanced Research Projects Agency, known colloquially as DARPA, uses its $3.2 billion annual budget to fund projects in an attempt to jump-start stagnating fields forward. The agency purposefully selects projects that are “DARPA hard,” meaning almost, but not quite impossible, assembles a brain trust of researchers and throws money at the problem for a discrete period of time – usually two-to-six years – until the project is completed or deemed fruitless. 

Prosthetics are an unusual detour for DARPA, which typically funds projects that are directly applicable to military technology. (DARPA’s most famous successes include computer networking, graphic user interface and Sputnik, the first artificial satellite.) This time the project was personal; the agency was motivated by the vast numbers of soldiers and airmen returning from duty in Iraq and Afghanistan missing limbs; the conflicts have created 1,286 amputees according to statistics released in July. This is only a small percentage of the 41,000 Americans who receive amputations each year, but veterans represent a much larger chunk of upper-level amputations. “One of the big causes of an upper limb amputation are combat related events - a blast, some sort of trauma,” said George Gordo, research coordinator at the Amputee Alliance, “The vast majority of amputees lose a lower limb, from diabetes or some sort of infection.”

Likewise, DARPA’s funding – just over $150 million in the last six-years – represents a small fraction of all prosthetics research funding, typically provided by the National Institute of Health and the Department of Veterans Affairs. But unlike grants from NIH and the VA, which require concrete feasibility studies the DARPA grants come no-strings attached. “They basically gave us a carte blanche to do whatever we wanted,” said Richard Weir, an engineer with the Rehabilitation Institute of Chicago, who was recruited in 2008 by DARPA to work with a team from Johns Hopkins on an electric arm prototype.

DARPA’s outrageous dream-teams are also unlikely under a typical grant structure; the prosthetics project includes over 300 researchers of medicine, neuroscience, orthopedics, engineering, materials science, mathematics, manufacturing and psychology, including such unlikely participants as Dean Kamin, a reclusive engineer most famous for inventing the Segway.  The chance to work on a modern-day Manhattan project was enough to draw talented researchers; Weir re-trained several research assistants in prosthetics technology to participate. “It was exciting…a rare chance. No way would anyone have built an arm like that without DARPA because, in the prosthetics business, it wouldn’t have been practical,” said Weir. “We wouldn’t have gotten the grants and would have been doing the work one grant at a time rather than all in one go.”

Kip Ludwig, a program director with the National Institute of Health, agrees. “[For NIH grants] usually there has to be a fair amount of compelling preliminary data that goes through a pretty extensive peer review process,” he said. “The more peer review data you can get through, usually the better the program. DARPA is the exception to this because they have money to risk on ‘out there’ projects.”

After six years and two, two-year extensions, the DARPA program is winding down – only 7 million is reserved in 2013 budgets for prosthetics research. Though the prosthetics program is considered a success by the agency, according to Ludwig, who specializes in neural interfaces, a brain implant that, widespread use of Darpa’s nerve-interfaced or neural devices is still “at least” decade away.

“[DARPA] demonstrations might seem to show that a patient can bring a bottle to their mouth, but two out of eight times they can’t and someone has to come up and reset the bottle. And, there are four technicians in the room making sure there’s no sensor noise and that everything runs perfectly. There are a lot of things that need to be done before it’s available for home use.”

A few of the nerve-interface devices are just making it to clinical trial, but veterans have had access to the prototypes for about two years now. Though most of the soldiers that Martha McDade, president of the Given Limb Foundation, works with have been offered the new devices, few choose to try them. “It’s simpler choosing a body harness device; they’re easier to operate,” she said.

Even advanced devices that have been around for years have drawbacks. In 2006, Ryan Major was on patrol in Ramadi, Iraq when an explosive ripped the flesh from his left-leg; he lost his right leg due to infection a week later. Major, now 28, owns a pair of C-legs, an advanced lower prosthetic that came on the market in 1999, which uses a microprocessor to register weight for a realistic bending knee. But even after six years, daily exercise and three days a week of therapy, he still can’t use the $50,000 legs.

“The knees bend depending on how much pressure I’m putting on the toe,” said Major. “I have to trust that I’m stepping in time with [the C-legs] and that they won’t buckle. When I fall it can kind of, lower my confidence.”

The heft of the microprocessor also makes walking difficult. Since his accident, Major has entered kayaking, swimming and biking races, and even jumped out of a plane, but he still can’t maneuver the heavy prosthetics. Major’s mom, Lorrie Knight-Major, puts it simply: “Imagine you have to carry a pair of 20-pound weights every where you go; you’re not going to go as far, right.” Most days, Major uses his “Stubbys,” simple plastic prosthetics that are indistinguishable from what an amputee would’ve used fifty years ago.

Once the technology makes its way to the commercial market, there’s no guarantee that anyone other than veterans will be able to afford the advanced devices. Though veteran’s health plans will shell out almost anything for prosthetics, private plans and Medicare cap-out well under the cost of most advanced devices. Researchers estimate the Luke arm would retail for at least $100,000 – more than twice as much the most advanced device on the market today – and require near constant maintenance.  Most private health plans provide between $500 and $3,000 for prosthetics, and cap lifetime coverage at $10,000 (including fittings and maintenance) and one prosthetic device.

 This may be why only a third of American amputees use an “advanced” prosthetic, according to data from the National Institute of Health. “On balance, military amputees get higher quality devices,” said McDade, “most private insurance companies will not spend $40,000 for a leg.” A research paper sponsored by Department of Veterans Affairs, listed cost as the main obstacle for the new bionic limbs. “Without third-party coverage, the costs of the new technology may be a barrier to its widespread use,” it read.

It’s the gap between invention and funding that several open-source prosthetics companies are trying to fill in. The most notable of these groups, the Open Prosthetics Project, has created plans for a dozen simple, un-trademarked, prosthetics and made the plans available for free on the Internet. Ivan Owens, a costume designer based in Portland is trying to go one step further with his prosthetic hand – he’s raised just under $4,000 from donations on the crowd-sourcing site Fundly to support the development of his prosthetic fingers, which he’s already fitted to three people in South Africa, and plans to offer in a build-it-yourself kit. Owen’s hand uses a system of cables and pulleys, drawing inspiration from a prosthetic hand built by a dentist in 1836, which Owens points out, means it’s still in the public domain.

Owens has followed the DARPA project closely, but he doesn’t see it as something that will affect the lives of amputees.

“The technology is incredible and it’s really cool and stuff, but the majority of the earth’s population is never going to have the means to access that kind of technology,” said Owens. “My hand may be simpler, but it’s more realistic.”