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Research Project Summary:
Gait changes of older adults through use of a novel gait training device (Vizziq NT)
As the result of age-related decreases in leg strength, proprioceptive feedback, and interlimb coordination,
older individuals walk more slowly – taking shorter, wider, less coordinated and less symmetrical steps.
Unfortunately, conventional walkers (assistive devices) restrict normal alternating arm and leg movements,
further degrading gait. Slower, less symmetrical and less coordinated gait greatly increases the risk of
falling, frequently causing injuries that lead to serious, life-altering consequences.
The Vizziq Neuromuscular Trainer (NT) is a novel 4-wheel pivoting gait training device designed to: a)
encourage more symmetrical and faster walking by enhancing trunk and leg rotation with a spring-loaded
pivoting mechanism in the frame, and b) promote proper posture by means of upright handlebars positioned
within the frame of the device. This design is hypothesized to provide the user with properly-timed
proprioceptive feedback that includes: a) haptic feedback (i.e. sense of touch) via the handles, as the device
frame articulates in response to natural hip and shoulder rotation, and b) cyclical activation of the stretch
receptors in the muscles and joints. Through this enhanced feedback and associated neurofacilitation, the
Vizziq NT is thought to modulate the basic locomotor rhythm that is the basis of stable gait. Support for this
hypothesis would be outcomes such as: increased pelvic rotation, longer stride length, faster walking speed,
shorter double-support time, narrower step width, and greater gait cycle symmetry.
The goal of this project is to test whether the Vizziq Neuromuscular Trainer promotes natural
walking movements, such as normal speed of walking and gait symmetry, in people 55 and older.
If gait training with this device is effective at maintaining and /or improving dynamic balance and walking
speed in older adults, the outcome would likely be reduced fall risk and greater mobility and independence
in this population.
In the first stage of this project, we conducted a small, single-session (cross-sectional) study comparing
gait variables in participants walking using the Vizziq NT and 2-wheel and 4-wheel conventional walkers.
Participants were older (65yr+) adults who were not regular assistive device users. Specific gait variables
measured were those associated with risk of falls, including self-selected speed, stride length, double-
support time, and gait cycle symmetry. We found that participants walking with the Vizziq NT: a) moved
4% faster (p=0.02) when compared to using a 2-wheel walker, and 2) had 18% greater pelvic rotation
(p=0.04) than when using a 4-wheel walker.
Based on these initial findings, we conducted a longitudinal training study comparing walking
variables in older adults before and after a several week training period with the Vizziq NT. The
goal of this study was to determine whether participants who trained (practiced walking) with the Vizziq NT
would improve key aspects of their gait compared to another set of participants (control group) who walked
an equivalent amount without the device.
Experimental Design: We randomly assigned
27 female participants (ages 55-88) to a
control group who practiced normal walking
(NW) or to a group who practiced walking with
the Vizziq NT (VW). Under the supervision of a
researcher, both groups walked according to
their assigned practice mode at a self-selected
pace three times per week for 20 minutes
(sufficient repetitions to learn a novel motor
task). Throughout the study, we assessed gait
variables using a GWalk inertial sensor during
pre-training and post-training assessments of
gait variables in all participants walking with
and without the device.
Results:
Training-Specific Learning—Walking Speed: Participants who trained with the Vizziq (blue) increased
their walking speed while using the Vizziq by 0.11
m/s by the end of the study – a statistically
significant improvement (p=0.003). This
improvement in speed contrasts with the loss in
speed that typically develops when using a
conventional walker. The group who did normal
walking (yellow) training had a 0.04 m/s
increase in walking speed, a non-significant
difference compared to pre-training speed
(p=0.08). Comparing the training groups at the
end of the experiment, when we accounted for
age as a confounding factor, participants training
with the Vizziq and assessed with it walked
statistically significantly faster (p=0.04) than the
walking trained group assessed while walking
unassisted.
Training-Specific Learning—Stride Length:
Participants who trained with the Vizziq (blue)
increased their stride length while using the
Vizziq by 0.07 m by the end of the study – a
statistically significant improvement (p=0.02).
The group who did normal walking (yellow)
training did not significantly increase their stride
length while walking (p=0.21). Comparing the
training groups at the end of the experiment,
when we accounted for age as a confounding
factor, participants training with the Vizziq and
assessed with it trended toward longer a longer
stride length (p=0.06) than the walking trained
group assessed while walking unassisted.
Cross-Training Learning--Speed: Here we see how well the learning under one training modality can
cross over as a pre-to-post improvement in the other modality during the final assessment. As shown, the
Vizziq-training group significantly improved speed, not only when assessed with the Vizziq (blue), but also
during unassisted walking (dark blue) (p=0.03). This finding is consistent with our hypothesis that training
with the Vizziq facilitates neural
pathways through proprioceptive
feedback to reinforce a faster locomotor
pattern, one that can persist even when
walking without the device.
Interestingly, the group that trained
using normal (unassisted) walking also
improved their pre-to-post speed when
assessed using the Vizziq (orange)
(p=0.01). This shows that after only a
few interactions with the Vizziq (at
assessment sessions), the walking-
trained group was able to use the Vizziq
efficiently enough to increase their
walking speed.
Vizziq Walking Speed versus Unassisted (Normal) Walking Speed: Both the Vizziq Training Group
(blue) (p=0.01) and the Normal Waking Training Group (yellow) (p=0.03) walked more slowly with the
Vizziq than in unassisted walking at their
pre-training assessment; the difference
was approximately 0.05 m/s for both
groups. By the post-training assessment,
at speeds faster than pre-training,
participants in the Vizziq Training Group
(blue) walked at essentially the same
speed (p=0.51) either with or without the
device. The Normal Walking Training
Group (yellow), post-training, still walked
slower while using the Vizziq than without
it (p=0.05).
Conclusion:
Based on measured improvements in walking speed and stride length, our findings provide
evidence that regular use of the Vizziq Neuromuscular Trainer is superior to regular walking
practice as a means of improving walking patterns in older individuals; eliciting improvements
that persist even when walking without the device. These results are consistent with our
hypothesis that the pivoting articulated frame of the Vizziq NT enhances proprioceptive feedback
and associated neurofacilitation that positively modulates the basic locomotor rhythm. We
suggest that preventative gait training with the Vizziq NT could reduce fall risk and the need for
conventional walkers in older adults.
Research Collaborators: Chi Na Moua, Nicole Szyszka, Courtney Kirkeide, and Marcella J. Myers.
Biology Department and Women’s Health Integrative Research (WHIR) Center, St. Catherine
University
Funding: This research was funded by a Summer Scholars grant from the Office of Collaborative
Undergraduate Research, St Catherine University