July 29, 2014

Eastern Michigan University, College Park Industries develop new technology to shed light on how forces affect amputees, prosthetics

by Pamela Young, Published August 13, 2009

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YPSILANTI — When Frank Fedel joined Eastern Michigan University's orthotics and prosthetics master’s degree program in 2003, he was surprised by the lack of hard data that could show whether a prosthetic worked the way it was meant to.

"I wanted to see something that said, 'OK, we're making a difference,'" said Fedel, an exercise science lecturer at EMU. "I come from a medical background (cardiac rehabilitation) where we needed to document that we had an outcome at the end of it — an EKG score that was more normal, a lower heart rate. ... I thought we (in O&P) needed to move toward a more objective, outcomes-based performance model."

So Fedel joined forces with a team of engineers from College Park Industries, a company in Fraser that makes prosthetic feet, to co-invent and develop the Intelligent Prosthetic Endoskeletal Component System (iPecs) — a device that can shed new light on the forces of everyday life on amputees and their prosthetics.

Initially, iPecs will be a research tool, Fedel said. But, ultimately, he'd like to see it become as commonplace for amputees as heart rate monitors are to cardiac patients or blood sugar monitors are to diabetics. It would help those with prosthetics detect and head off potential problems as they get back to normal activities.

Thus far, College Park has tested the device in university gait labs at Northwestern and Georgia Tech. The company received a $165,000 grant from the National Institutes for Health (NIH), through the Eunice Kennedy Shriver National Institute Of Child Health & Human Development, to fund the first phase of the project. Senior research and engineering officer Mike Leydet said College Park hopes to have iPecs ready to release this fall.

"In the past, when people with an amputation walked around, you'd have a person with experience in gait analysis look at someone with an amputation as they walked around and they'd say, 'OK, you look like you're walking normally,'" Fedel said. "Or, if not, they'd try to adjust the prosthesis. But 'walking normally' is kind of a subjective thing."

To get more meaningful measurements, researchers and prostheticists use gait labs that typically involve a lot of expensive equipment — force plates mounted in the floor, camera systems and computers to run complex calculations.

The iPecs device, which is about the size of a Tim Horton's muffin, is incorporated into the prosthetic system, where it measures the force being transmitted from the ground into the person's leg. The device can monitor the position of the foot and tell which way the toes are pointing. It can reveal twisting, direction of force and other parameters that will help clinicians and researchers refine the way a prosthetic limb fits and performs. Fedel's biomechanics background helped steer iPecs' features and functions.

The idea of attaching measurement devices to prosthetics goes back to the late 1960s, Leydet said. What makes iPecs different is that it combines standard strain gauges with cell phone technology so the device can provide an accurate measurement without battery packs and wires. The device can be set up to transmit data wirelessly to a nearby computer or record it on a micro SD memory card to be downloaded later via a USB cable. Even the best gait labs, with force plates in the floor and cameras and computerized movement models, can't offer that on an everyday basis.

It's unobtrusive and, therefore, less likely to influence test results.

"iPecs provides data on every step," Leydet said. "A person can go outside the lab and collect data in a real-world environment. It's taking gait analysis beyond the lab."

The first crude version of the iPecs was cobbled together and tested in a lab at EMU.

"We thought we could hammer it out pretty easily, but there was a lot of error and drift," Leydet said. "We just didn't have a very robust design, but it was a very pivotal moment in understanding the need for accuracy and precision in measurements."

Subsequent versions have taken that accuracy and precision well beyond what the human eye can detect. Not to knock humans, but Fedel points out that, over the course of years, a small misalignment, undetectable to the human eye, could mean the difference between mobility and arthritis in an overcompensating "good" limb.

Though iPecs is being developed to use with prosthetic feet, Fedel said the device has potential in other fields, too.

In sports, it could be used to gather information about what's happening when a person tries to balance (i.e. gymnastics) or to measure the force of impact (football, boxing). In industry, the device could provide a better picture of what the body experiences during a car crash, or be combined with robotics as a sensing system.

"One of the design criteria was to make it as flexible as possible," Fedel said. "The road starts with research and now we can really see what's going on all the time."

Pamela Young

pyoung@emich.edu

734.487.4400

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