First brain-controlled bionic leg could help millions of amputees

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While researchers and engineers have been busy over the years working on brain-controlled bionic arms and hands, legs have been somewhat left behind. Until now, that is.

In a development that could one day dramatically transform the lives of millions of leg amputees, the Center for Bionic Medicine at the Rehabilitation Institute of Chicago said recently it had made significant progress with its work on a thought-controlled prosthetic leg that allows a user to move it like a natural leg when walking, climbing stairs, and so on.

The bionic leg, which has been in development for the last four years, has been made possible thanks to an $8 million grant from the US Army’s Telemedicine and Advanced Technology Research Center. The results of the researchers’ work was published recently in the New England Journal of Medicine.

Linking brain and leg

The team behind the technology has successfully linked up the movement signal originating in the brain – which passes down the spinal cord and peripheral nerves – with the bionic leg. This involves ‘rewiring’ a patient to redirect severed nerves into the hamstring. Those nerves still release a small burst of electricity when the amputee thinks about moving their leg, with a pattern-detection computer system transforming the thought into movement.

According to a Bloomberg report, the error rate, which includes the risk of falls, has been reduced dramatically from 12.9 percent with a standard robotic leg to just 1.8 percent with this latest creation.

Work is now underway to improve its accuracy and make the motorized machine smaller, quieter, and more robust.

If its development goes according to plan, the revolutionary artificial limb could be made available within the next five years to millions of leg amputees around the world.


Zac Vawter, who lost his leg from just above the right knee following a motorcycle accident four years ago, is currently testing out the bionic leg in special weekly sessions at the center in Chicago.

Speaking to Bloomberg about the the artificial limb, he described it as being “in between the leg I wear every day and prior to amputation. It’s a dramatic improvement over my current prosthetic, but there is still a long way to go.”

Vawter added, “In my mind, it’s still the same thing in terms of moving my ankle down or up, or extending my leg forward or back. It’s just walk like I would normally walk. It’s not special training or buttons or tricks. That’s a big piece of what I think is groundbreaking and phenomenal about this work.”

[via Daily Tech] [Image: Solarseven / Shutterstock]

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