Trunk sway and gait asymmetry improved among individuals with
transtibial amputations who used a lower extremity ambulatory feedback system,
according to a study published in Gait & Posture.
“We’ve been working with sound sensors in shoes to come up
with a way to measure how patients with transtibial amputations are walking
without being in a motion analysis lab so we can look at them moving in their
own home environment,” Stacy J. Morris Bamberg, ScD, assistant
professor of the department of mechanical engineering at the University of
Utah, told O&P Business News. “We decided to build this system
where we put the sensors in the shoes to measure how the person was walking in
real time and give feedback through a computer. We did this study because we
wanted to find out if changing the gait is something that amputees are able to
do if we give them feedback.”
Improvements in gait, symmetry
Three transtibial amputees with gait asymmetry from the University of
Utah Rehabilitation Program used a gait asymmetry detection system called the
lower extremity ambulatory feedback system (LEAFS) for six 30-minute training
sessions over 3 weeks. Patients also performed a pre- and post-test in a
clinical motion analysis lab one week before and after training.
LEAFS improved at least one of the outcome measures of gait asymmetry
determined by the motion analysis lab in two of the three patients. Trunk sway
was reduced in one patient by 85.5% and by 16% in the other patient while
symmetry ratio increased toward unity by 26.5%, according to the study.
Researchers found no improvements in gait symmetry or trunk sway in the third
“The two patients that improved didn’t have a lot of health
issues before their amputation. It was due to an infection, while the patient
who had a hard time using the device had an amputation due to emboli in both
legs. She only had one leg amputated, but her other leg still had some residual
issues,” Bamberg, president of Veristride, which produces and sells the
detection system, said. “Now our hypothesis is that using our device will
be straightforward for people who have had an amputation due to trauma because
that other limb is still relatively intact, so they’ll be able to use the
feedback and quickly make a change in how they walk.”
Bamberg and colleagues hope that when patients go to physical therapy
appointments, their physical therapist will help them set realistic goals to
work on during the time until their next appointment. By setting the goals on
the LEAFS program, the patient could use it independently to work on improving
“Our goal is that patients wouldn’t necessarily use our device
forever, but they would use it until they get back to a symmetrical gait and
are comfortable walking,” Bamberg said. “It wouldn’t replace
physical therapy appointments, but be in conjunction and perhaps cut down on
the number of appointments.” If perfect symmetry isn’t the goal for a
patient with a high level knee amputation, for example, “maybe we can get
them to a little bit more symmetry so they’re unloading their intact knee
and decreasing the risk for osteoarthritis.”
Updates in the device
After the initial study, Bamberg and colleagues performed a second study
to further improve the LEAFS system and insole sensor system. Twelve
participants with no abnormal gait installed the sensor system into their shoes
and used the adaptive, real-time instrumentation system for tread imbalance
correction to perform several walking tests to assess the system’s ability
to influence gait.
Participants walked normally down a 200-foot hallway while the system
stored gait data to use as a control. Then they walked three separate times,
each with a different sensory feedback method: visual, audible or vibrotactile.
Participants received feedback from the system through an Android-platform
smartphone that would induce gait asymmetry. At the end of all three walks,
participants filled out a survey about which feedback method they preferred.
Researchers found that the visual feedback was successful in modulating
the normal gait of all participants. Vibrotactile feedback also induced a
statistically significant variance in gait, but study results showed audible
feedback did not. Participants expressed that they preferred the visual
feedback system over vibrotactile and audible.
“This system has potential for use in the rehabilitation and
training of subjects who have undergone lower limb amputations, suffered from a
stroke or who have Parkinson’s disease. In this way, it can serve as a
supplemental rehabilitation method for use both in the clinic, and as a
personal assistive health care device,” the researchers concluded.
“To further develop this device, we will initially focus on further
developing the auditory and vibrotactile feedback options, along with
optimizing the power requirements, and shrinking the size of the associated
electronics. Our next step is to use [the device] in a larger study, to
investigate its effects on persons with gait abnormalities. We are particularly
interested in assisting persons with lower limb amputations to regain symmetric
gait.” — by Casey Murphy
For more information:
Redd CB, Bamberg SJM. A wireless sensory feedback device for real-time
gait feedback and training. IEEE ASME Trans Mechatron. 2012;17:425-433.
Yang L, Dyer PS, Carson RJ, et al. Utilization of a lower extremity
ambulatory feedback system to reduce gait asymmetry in transtibial amputation
gait. Gait Posture. 2012;36:631-634.
Disclosure: Bamberg is president of Veristride.