Researchers throughout the world comprise a dedicated effort to ultimately produce robotic powered arms and hands indistinguishable – at least in function – from a biological limb.

“Advanced hands have been wonderful in terms of prosthetics that look like actual hands and have greater capabilities, but without a sense of feeling, users see them as a tool. But when we turn on the sense of touch, they feel like they are using their own hands. Our data also show they are better able to control the prosthetic, even without changing the control algorithm,” he said.

“So the sense of touch gives them a better sense of embodiment, which means they incorporate the prosthetic into their body image and begin to see it as part of themselves. Our subjects refer to it as their ‘hand’ rather than as a prosthetic.”

Tyler’s group at Case Western is in early feasibility clinical trials, but he predicted it will be another five to ten years before it becomes widely available – depending on funding and other aspects.

“I’ve long been interested in neurological implants, probably the most feasible way to go right now, but I’m not sure it can be done in the next five years. Once they do, however, it will move quickly into all kinds of applications. The big question now is how long can that neural interface exist before the nerve loses its ability to stimulate effects.”

“That being said, in the development components, most of the technology exists and has been around for a long time. We’re working with a lot of companies to develop components we believe will make it available – we just need to put the technologies together for the prosthetic application and do the clinical work,” he added. “In terms of sensory feedback, upper limbs are further along. We’ve had people working with those for up to three years. We’re not in trials yet on lower limbs, but hope to be within months, not years.

“Another thing we’re excited about investigating is what’s called ‘phantom limb sensation’ … [sometimes described as] a nail being driven in or the hand being crushed. But when we started testing our sensory feedback component, they said the pain went away. Right now, they only get stimulation in the lab, about six hours every two weeks. But even with just that, they report the pain has disappeared. We think that is a very significant component, having to do with the absence of information and how the brain fills in that space.”

While head of the VA’s artificial limb program for 30 years, Downs changed the rules to allow veterans to have whatever technologies were available – including multiple devices for multiple applications.

“I still have the old hook I’ve had for 47 years, but the DEKA arm I have is the third generation and is much more functional. And each new generation of arm or wheelchair that comes out is better because it is based on previous versions,” he said. “There are different types of prosthetic limbs for different activities – walking, running, showering. The human limb does it all.

“With prosthetics, we’re trying to improve function as much as possible with the available technologies. The more tools you have, the more accomplished you can become. I look at the hook and the robotic hand and both have function for me, so I need them both to be complete.”

Not every amputee shares that view in the long run, however.

“Abandonment is a big issue with prosthetics,” Tyler noted. “The lack of sensation, we believe, is a big part of that, especially if it is a single limb loss. Many people can accommodate and function quite effectively with only one hand or arm, so is it really worth everything that comes with using a marginally effective artificial hand to which you have no real connection, in terms of feeling?

“I think a lack of connection has always been one of the biggest challenges with prosthetics, not just using the hand, but connecting to the world in ways you could not before. Even with complex-looking and -performing hands, the biggest gains will be sensory feedback, leading to more fine control.”

Having been a central part of the process for nearly half a century, Downs has had a closer look than most Americans at how war generates technology development, especially in medicine, but also what happens when the war ends. As Operation Enduring Freedom and Operation Iraqi Freedom retreat to the history books, he predicts RDT&E to push prosthetic development will fade into the background again, as it did after Vietnam and Desert Storm.

“There has been so much press about [prosthetics] in the past few years, but as the war fades into memory, so will the money and congressional interest in pursuing more advances. And there will be fewer numbers of new amputees and it won’t be big news anymore,” he said, adding that may delay development and availability of future breakthroughs.

“I’ve long been interested in neurological implants, probably the most feasible way to go right now, but I’m not sure it can be done in the next five years. Once they do, however, it will move quickly into all kinds of applications. The big question now is how long can that neural interface exist before the nerve loses its ability to stimulate effects.”

While he sees a slowdown as inevitable and user attitudes changing with time and age, Downs does not see prosthetic evolution – even revolution – stopping.

“But it has to be practical and functional to be effective enough for an individual to want to wear it. A lot of leg amputees discover that with higher amputations, wheelchairs are a lot easier to use,” he said. “The body only has so much tolerance for gadgetry, and if it causes pain or breaks down too easily or often, then it won’t be used.

“I don’t feel handicapped when I’m wearing my robotic arm. The hook was psychologically difficult to adjust to – and the Army left it up to me to figure out how to use it. The current generation is far more accepting of technology and today’s soldiers are proud of their prosthetics, which is a definite change of attitude from my day.”

This article was first published in The Year in Military Medicine and Veterans Affairs: 2015-2016 Edition.