Robotic Limbs To Do Away with Wheelchairs?

May 09, 2011
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In 2005, when Hailey Daniswicz was twelve, the now sophomore at Northwestern University lost her leg due to bone cancer.  At the age of 14, she made the life changing decision to amputate a leg that had lost its usability to the disease.  “Finally I reached a point where I thought my quality of life would be better if I had an amputation and got around on a prosthetic,” she said.

She, along with seven other amputees, are currently in a study funded by the US Army which is teaching a computer to distinguish movements in her thigh.  Then she will be able to use a robotic leg prosthesis that she will be in command of by using her nerves and muscles.   The prosthetic would be controllable by thought. According to Levi Hargrove, a research scientist at the Rehabilitation Institute of Chicago, “We’re really integrating the machine with the person”. “We were expecting to be able to control a knee using only the muscles of the thigh, but we didn’t expect to be able to control an ankle without having surgery.”

The study uses “electromyography (electrical signs created by muscles) and pattern recognition computer software to control a new generation of robotic limbs”.  Electrodes are attached to her thigh muscles and pick up signals from her nerves to the muscles.  One newspaper reported that signals are created in a precise “pattern depending on how a person intends to move. Each person was asked to start concentrating on movements such as flexions or extensions of the knee making their muscles contract.   With training, the computer can learn a person’s signal pattern for when they want to bend a knee or flex an ankle and it makes the” robotic prosthesis move. .”

“The way most prosthetics work now is you have mechanical sensors. You have to push and interact with them,” says Hargrove “With this you measure the actual neural intent and have that tell the motor what to do.” I anticipate that we’ll be able to be walking within the safety of our lab within the next year,” Hargrove said.  “And then as soon as we’re comfortable in our walking then we’ll start going to more complex activities such as stair-climbing and stair-descent.”

Author: Melissa