Prosthetic Leg - CASIT - UCLA

1/31/13 Print - Feedback System Lets Amputees "Feel" Prosthetic Leg - Popular Mechanicshttp://www.popularmechanics.com/science/health/prosthetics/feedback-system-lets-amputees-feelprosthetic-leg-14821609Feedback System Lets Amputees "Feel"Prosthetic LegA sensorized shoe insole translates pressure into tactile feedback, helping amputees learn to walkon a prosthetic limb with a normal, healthy gait.BY SARAH FECHTCarbon-fiber and plastic polymers aremaking artificial limbs stronger and lighter.They can be controlled using just a thoughtor a muscle twitch. They can even be reengineeredfor rock-climbing or Olympicsprinting. But a continuing problem is thatmost prosthetic limbs don’t provide sensoryfeedback to the user.As you walk, muscles and neurons constantlysend information to your brain about whereyour legs are, where your feet hit the ground,and how hard they push off. Without thatfeedback, it can be hard to coordinatemovement. As a result, amputees who wearprosthetic legs commonly develop gaitabnormalities such as shorter strides, slowerwalking speeds, and standing on tip-toe toswing the prosthetic leg.Marilynn Wyatt, Nav al Medical Center San Diego"The lack of sensation can affect mobility andquality of life," says Zachary McKinney, agraduate student in biomedical engineering at UCLA. McKinney and his colleagues have beenworking on a simple feedback system that can be incorporated with almost any below-the-kneeprosthetic leg. "Our goal is to improve sensory awareness of the prosthetic," he said at a meetingof the Biomedical Engineering Society in late October.The system uses tactile feedback on the thigh to tell the amputee whether he’s stepping on thecorrect parts of his prosthetic foot with the proper amount of force. The device won’t make theprosthetic leg "feel" like a living leg, but it can provide instantaneous feedback to help the amputeecorrect his gait.The setup consists of three parts: a shoe insole that collects information from the foot; a datarelaycenter worn on the torso; and a cuff on the thigh that uses pressure to communicate with theuser. The shoe insole has four sensors that pick up how the amputee is stepping on the prostheticfoot. Located at the heel, the big toe, and on the left and right sides of the ball of the foot, thesensors collect pressure information and send it to a small data processor that’s strapped aroundthe user’s torso. The processor uses the information to pneumatically inflate several dime-sizedsilicone balloons on the thigh cuff.www.popularmechanics.com/print-this/feedback-system-lets-amputees-feel-prosthetic-leg-14821609?page=all 1/2