When Frank Fedel joined Eastern Michigan University's
orthotics and prosthetics masters 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."
 |
PROSTHETIC CALCULATIONS: Frank Fedel,
an
exercise science lecturer at EMU, measures the
force
of a prosthetic foot. Fedel and engineers
from College
Park Industries have co-invented iPecs,
a device that
can measure gait analysis, reveal twisting, direction
of force and other parameters that will help clinicians
and researchers refine the way a prosthetic limb
fits
and performs. |
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 says 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."
