Prosthetic leg is first that can be controlled by thought

Los Angeles Times : Zac Vawter lost a leg in a motorcycle accident in 2009. Thanks to an $8 million grant from the US Army to the Rehabilitation Institute of Chicago, he is the first person to use a prosthetic leg that can be controlled by the wearer’s thoughts. The leg, which weighs just over 10 lbs (4.5 kg), has two independent motors that move the ankle and knee, and a variety of sensors, including accelerometers and gyroscopes. Once strapped into place, the prosthesis is connected to a collection of specific locations on Vawter’s thigh via a series of electrodes. The electrodes identify specific muscle contractions that the computer chips in the prosthesis have been trained to associate with specific movements. After his amputation, Vawter underwent a special procedure that preserved nerves that would normally have been left to die; instead they were rearranged to control specific muscles. With the new leg, Vawter has the ability to curl his toes and adjust the angle of his ankle to walk on inclines, and he can perform those actions simply by thinking about them. The new device has reduced the number of errors incurred by noncontrolled prosthetics by 44%.