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Wednesday October 9, 2013 MYT 12:00:00 AM
Wednesday October 9, 2013 MYT 5:08:00 AM
by juan perez jr
Chicago researchers are pushing the envelope in the field of
ZAC Vawter’s right leg weighs about 4.5kg, slightly less than his left. But it works normally; he doesn’t have to do much more than think to rotate his ankle, walk or climb stairs.
Rather than tissue and bone, the 32-year-old amputee’s right leg is a prosthetic made of aluminum, two motors, sensors and a powerful computer system.
Vawter is wearing millions of dollars worth of emerging technology that could transform the lives of wounded veterans, accident victims and the elderly. Vawter’s bionic leg can basically read his mind.
A group of Chicago researchers is using about US$8mil (RM25.88mil) of the Army’s money to expand the experimental field of mind-controlled prosthetics, with hopes of bringing the technology to military and consumer markets in the next five years.
The Rehabilitation Institute of Chicago unveiled the latest prototype bionic device last week, in conjunction with its report on robotic leg control. The study published in The New England Journal Of Medicine on Oct 3 is a progress report on a project with a long history and years of work remaining, but can also be seen as affirmation of progress.
“We’re laying the foundation for the advances that are to come,” said Levi Hargrove, head of the centre’s lab for neurally engineered prosthetics and orthotics.
Colonel John Scherer sees the technology’s potential. From Fort Detrick, Maryland, he directs Army research intended to restore as much function as possible to veterans suffering from traumatic injuries involving limited mobility, or vision and hearing loss.
There are more than 1,600 amputees from the Iraq and Afghanistan wars, Scherer said. About 80% of that population has lower-extremity amputations, he said. Although prosthetic technology has improved since 2001, the existing technology isn’t necessarily designed for a young, active population, Scherer said.
“We’re trying to say, ‘Hey, we have a population that needs advancements as well’,” Scherer said. “So we’re obviously funding projects in those areas to make those advancements so our injured service members can resume the life that they want to live.”
Transforming Vawter into a version of the Six Million Dollar Man relied on a rather straightforward concept. In 2009, Vawter sped a Suzuki motorcycle too quickly through a curve on a rural Washington road. The resulting crash forced doctors to amputate the lower part of his right leg.
During surgery, doctors rewired Vawter’s severed nerves into surviving leg muscles, laying the groundwork for advanced prosthetics. Within months, Vawter could flex his upper leg when prompted to try to plant or rotate his missing foot. His brain was sending clear, electrical signals to a body part that didn’t exist. Vawter began working with the rehabilitation centre in December 2010.
Researchers measured his brain signals while he tried to flex and extend the missing knee and ankle. The centre’s team also developed elaborate software using tens of thousands of lines of code to translate the neural signals into specific leg motions.
“It’s a fascinating world,” said Vawter, a software engineer, while testing the prosthesis inside a 14th-floor laboratory at the rehabilitation institute.
“It’s neat to see the way they’re using software, algorithms and machine learning to make this work,” the Washington resident said.
The prosthetic’s knee and ankle joints are powered by two small motors. Thirteen mechanical sensors are embedded along the prosthetic, including an accelerometer, gyroscope and sensors to determine how much weight Vawter puts on the leg, or how fast he’s moving.
Small metal electrodes are attached to Vawter’s remaining leg to catch his neural signals.
Vawter used an earlier prototype of the leg to climb 103 stories of the Willis Tower last year. The latest version has dramatic software improvements that allow him complete independence and a seamless range of motion directed by his thoughts.
The prosthetic used at Willis Tower last year only had modes for walking and stair climbing and required a team of engineers to monitor the device, Hargrove said.
“This is a huge breakthrough,” he said. “It’s no longer, ‘OK, we’re giving you the choice to walk or climb stairs’. We are giving you the choice to do whatever you want to do. That wasn’t possible (before).
“He has freedom. He could walk out of the building with it and go until the battery died. There isn’t anything stopping him from doing that other than maybe security at the front desk.”
Researchers will continue to refine the mechanics to reduce the potential for fall-inducing errors. It’ll be up to the marketplace to improve the technology further and attach a price tag to it. The team, though, is thrilled with the progress.
“I never, ever thought we would accomplish so much in five years. Never,” Hargrove said in the lab. “I’m glad we have.”
“Ditto that,” Vawter replied. – Chicago Tribune/McClatchy-Tribune Information Services
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Lifestyle, Science & Technology, bionic, robotic prosthetics, artificial leg
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