More than 80% of stroke survivors experience walking difficulty,
significantly impacting their daily lives, independence, and overall
quality of life. Now, new research from the University of Massachusetts
Amherst pushes forward the bounds of stroke recovery with a unique
robotic hip exoskeleton, designed as a training tool to improve walking
function. This invites the possibility of new therapies that are more
accessible and easier to translate from practice to daily life compared
to current rehabilitation methods.
Following stroke, people often experience walking asymmetry, where one step is shorter than the other. The study, published in IEEE Transactions on Neural Systems and Rehabilitation Engineering,
reveals that the robotic hip exoskeleton has the potential to
effectively train individuals to modify their walking asymmetry,
presenting a promising avenue for stroke rehabilitation.
The approach employed by the robotic exoskeleton is inspired by
split-belt treadmills, which are specialized machines with two
side-by-side belts moving at different speeds. Prior research has shown
that repeated training on a split-belt treadmill can reduce walking
asymmetry in stroke patients.
Wouter Hoogkamer, assistant professor of kinesiology and author on
the paper, has spent the last decade studying split-belt treadmills.
"Split-belt treadmill training is designed to exaggerate a stroke
patient's walking asymmetry by running the belts under each foot at
different speeds. Over time, the nervous system adapts, such that when
the belts are set to the same speed, they walk more symmetrically."
Unfortunately, there are limits to the benefits gained from treadmill-based training methods.
What is learned on a treadmill does not completely transfer to
overground contexts. This is because walking on a treadmill is not
exactly the same as walking overground."
Banu Abdikadirova, mechanical and industrial engineering doctoral candidate and lead study author
"The ultimate goal of gait rehabilitation is not to improve walking
on a treadmill – it is to improve locomotor function overground," says
Meghan Huber, assistant professor of mechanical and industrial
engineering and senior author on the paper. "With this in mind, our
focus is to develop methods of gait rehabilitation that translate to
functional improvements in real-world contexts."
With this motivation, the UMass team sought a novel way to exaggerate walking asymmetry without a treadmill.
This
proof-of-concept study showed that applying resistive forces about one
hip joint and assistive forces about the other with their exoskeleton
mimicked the effects of split-belt treadmill training in neurologically
intact individuals.
Now that the research team has proven that the exoskeleton can alter
gait asymmetry, they are eager to move their research into overground
contexts that are more akin to the real world.
"Because our exoskeleton is portable, it can be used during overground walking," says Mark Price,
a postdoctoral researcher in mechanical and industrial engineering and
kinesiology and author on the paper. "We can build upon the successes of
split-belt treadmill training with this device to enhance the
accessibility of gait training and enhance the transfer of training
benefits into everyday walking contexts."
The researchers also plan to expand their work by measuring the
neural changes caused by walking with the exoskeleton and testing this
new method on stroke survivors.
"A portable exoskeleton offers numerous clinical benefits," says
Abdikadirova. "Such a device can be seamlessly integrated into the daily
lives of chronic stroke survivors, offering an accessible way to
increase training time, which is critical for improving walking. It can
also be used during early intervention in hospitals for improved
functional outcomes."
The robotic hip exoskeleton is just one of the innovative devices
designed to study and enhance gait function developed by the
collaborative team of undergraduate students, graduate students, and
postdoctoral researchers from the Human Robot Systems Lab, led by Huber,
and the Integrative Locomotion Lab, led by Hoogkamer.
"It is inspiring to witness the innovations that emerge when
individuals from diverse backgrounds unite under a shared mission," says
Huber. "Only through this type of cross-disciplinary research can we
engineer technologies that can have a meaningful impact on people's
lives."
Source:
Journal reference:
Abdikadirova, A., et al. (2024) Gait Adaptation to Asymmetric Hip Stiffness Applied by a Robotic Exoskeleton. IEEE Transactions on Neural Systems and Rehabilitation Engineering. doi.org/10.1109/TNSRE.2024.3354517.
