Bionic limbs will one day sense the grass under prosthetic feet
October 14, 2013No Comments
With the first thought-controlled bionic leg pioneered in Chicago, the next steps for smart prosthetics are refining them for widespread use and tackling a huge hurdle: sensory feedback.
It sounds like something straight out of science fiction: artificial limbs that not only move, flex, and feel like their flesh counterparts, but also respond directly to one’s thoughts and even translate sensory feedback — the feeling of grass beneath one’s feet or the sensation of a limb floating in space — straight back to the brain.
Thanks to an aggressive push in funding from the US military in an effort to the improve the lives of injured veterans, those advancements are no longer such farfetched dreams. While the idea of “Blade Runner”-level prosthetics is still a far-off fantasy, impressively capable, thought-controlled bionic limbs are now a modern-day reality thanks to pioneering research between the Rehabilitation Institute of Chicago (RIC), DARPA, and a growing sector of companies developing the next generation of artificial limbs.
Just last month, the RIC announced that its research in bionics has yielded the first thought-controlled robotic leg. The research had already seen its fair share of headlines — including a climb of 103 flights of stairs on the single prosthetic unit — but the team led by Dr. Levi Hargrove waited to conclusively publish its findings in the The New England Journal of Medicine. The bionic hardware, which was more than eight years in the making, was coupled with a groundbreaking approach — targeted muscle reinnervation surgery — that empowers the brain to move parts of the bionic limb with nerves that are rerouted to healthy muscles.
But thought-controlled limbs are only the beginning. With a goal to one day provide lower-cost, sensory-enabled limbs that may use implants to generate even more precise movement, bionics research is on course to fundamentally change the world of prosthetics over the course of the next decade.
TMR: Controlling your ankle with your hamstring
In 2009, Zac Vawter was in a motorcycle accident that resulted in the amputation of his right leg below the knee. It turns out that, at roughly the same time, the RIC and Northwestern University were developing a procedure that would allow researchers to rewire nerves from damaged muscles to healthy ones, using the still-intact neural impulses to reroute movement.
Called targeted muscle reinnervation, or TMR, the surgery — first developed in 2009 by doctors Gregory Dumanian and Todd Kuiken — has worked for bionic hands and elbows, which can use rewired nerves placed onto larger muscles like biceps and pectorals to translate contractions in those healthy muscles to wrist and arm movements.
So the now-32-year-old Seattle native volunteered to undergo TMR and become a part of a multiyear research that’s backed by $8 million in funding from the US Army and additional financial support from DARPA, another big player in prosthetics that has helped foster cutting-edge bionic arms with its Revolutionizing Prosthetics program and advance the science that enables their movement with its Reliable Neural-Interface Technology program.