Zac Vawter’s bionic leg lets him walk up stairs with ease. That’s because it senses his brain’s instructions and moves accordingly, something that no other prosthetic leg can do.
The leg is the first of its kind to respond accurately to its user’s thoughts, according to a report published Sept. 26 in the New England Journal Of Medicine.
Vawter, now 32, was in a motorcycle accident in 2009. Doctors had to amputate his leg just above the knee.
He had heard about mind-controlled prosthetics, which had previously only been used with robotic arms. Legs are more problematic, because when they fail you are more likely to get badly injured, for instance, by falling down the stairs.
He asked about these new technologies and eventually became the “test-pilot” for a bionic leg created by Todd Kuiken’s team at the Rehabilitation Institute of Chicago. The project was partially funded by an $US8 million grant from the U.S. Army.
The bionic leg uses electrodes and a microprocessor to read Vawter’s intentions via muscle contractions in his thigh.
Normally, the brain sends electrical signals through the spinal cord to instruct muscles to move. For a leg amputee, those signals still occur, but there is no longer anywhere for that signal to go. Because of this the nerves near the amputation site tend to die off, leaving a dead circuit.
To avoid this, during the amputation, doctors rewired Vawter’s nerves so they could control muscle contractions in his thigh. This kept the nerves alive.
Source: Business Insider Australia