"Smart" Rehab Device for Walking-Impaired

by George Zamora

SOCORRO, N.M., February 4, 2003 -- Thompson Sarkodie-Gyan, an associate professor of mechanical engineering at New Mexico Tech, has developed a computer-controlled apparatus that promises to get walking- impaired patients back on their feet faster and more effectively than currently employed, labor-intensive rehabilitation programs.

The "smart gait-emulator," as Sarkodie-Gyan calls his latest invention, uses computer technology to process impulses received from a patient's good leg and interprets and mirrors the signals to accurately impose a natural walking stride onto the bad leg.

With the aid of a support harness and powerful actuators that move suspended bracings, patients are assisted by the "mechanical legs" on a treadmill, completing a full range of natural walking motions during their physical therapy sessions, without the help of trained specialists.

With a few more years of testing and development, the innovative technology has the potential of helping more than 29 million Americans with walking disabilities, Sarkodie-Gyan says.

"When we researched some of the problems associated with current rehabilitation programs and the tools they use, we found that one of the more common difficulties physical therapists face is maintaining the consistency in gait motion in their patients from one therapy session to the next," Sarkodie-Gyan points out.

"Also, most of the complaints we received from stroke victims concerning their rehabilitation programs were that they don't get enough time with their therapists on the treadmills or other machines they're using," he adds.

The smart gait-emulator, in contrast, uses cutting-edge computer and robotics technologies to automatically adjust its settings to each individual's personal walking characteristics, and accurately does so session after session.

In addition to providing independent, customized leg movements for rehab patients, the smart gait-emulator's computer also records any and all pertinent data.

"There's still a lot of big areas left to explore with this prototype model," says New Mexico Tech graduate student Silversun Sturgis, "for instance, how to emulate the two-dimensional hip motions we all make when we walk."

Sturgis was one of several Tech students who worked last year on a team project that was aimed at developing an ankle movement simulator, in conjunction with the smart gait-emulator project.

"We quickly found out that ankle and foot movements are very complicated -- so complicated that they warrant their own devices-- and decided to use actual foot contact on the treadmill rather than add another variable to the device," Sturgis explains.

An automatic adjustment feature, which would have a range of settings for patients of various heighths and builds, was also put on hold because of budgetary constraints.

The prototype of the smart gait-emulator was built for around $20,000, with most of the funding for the project provided by New Mexico Tech and much of the design and fabrication of its various mechanical parts performed by New Mexico Tech students.

"We're now hoping to get some outside funding for the next phase of the project," says Sarkodie-Gyan, "and are in the process of submitting several proposals for research grants."