Micro implants could
restore standing and walking
University of Alberta – December 3, 2019
-- When Vivian Mushahwar first applied to grad school, she wrote about her idea
to fix paralysis by rewiring the spinal cord.
It was only after she was accepted into
a bioengineering program that the young electrical engineer learned her idea
had actually prompted laughter.
"I figured, hey I can fix it, it's
just wires," Mushahwar said. "Yeah, well, it's not just wires. So I
had to learn the biology along the way."
It's taken Mushahwar a lot of work over
two decades at the University of Alberta, but the Canada Research Chair in
Functional Restoration is still fixated on the dream of helping people walk
again.
And thanks to an electrical spinal implant pioneered in her laboratory
and work in mapping the spinal cord, that dream could become a reality in the
next decade.
Because an injured spinal cord dies
back, it's not simply a matter of reconnecting a cable. Three herculean feats
are needed. You have to translate brain signals. You have to figure out and
control the spinal cord. And you have got to get the two sides talking again.
People tend to think the brain does all
the thinking, but Mushahwar says the spinal cord has built-in intelligence. A
complex chain of motor and sensory networks regulate everything from breathing
to bowels, while the brain stem's contribution is basically "go!" and
"faster!" Your spinal cord isn't just moving muscles, it's giving you
your natural gait.
Other researchers have tried different
avenues to restore movement. By sending electrical impulses into leg muscles,
it's possible to get people standing or walking again. But the effect is
strictly mechanical and not particularly effective. Mushahwar's research has
focused on restoring lower-body function after severe injuries using a tiny
spinal implant. Hair-like electrical wires plunge deep into the spinal grey
matter, sending electrical signals to trigger the networks that already know
how to do the hard work.
In a new paper in Scientific Reports,
the team showcases a map to identify which parts of the spinal cord trigger the
hip, knees, ankles and toes, and the areas that put movements together. The
work has shown that the spinal maps have been remarkably consistent across the
animal spectrum, but further work is required before moving to human trials.
\The implications of moving to a human
clinical setting would be massive, but must follow further
work that needs to
be done in animals. Being able to control standing and walking would improve
bone health, improve bowel and bladder function, and reduce pressure ulcers. It
could help treat cardiovascular disease -- the main cause of death for spinal
cord patients -- while bolstering mental health and quality of life. For those
with less severe spinal injuries, an implant could be therapeutic, removing the
need for months of grueling physical therapy regimes that have limited success.
"We think that intraspinal
stimulation itself will get people to start walking longer and longer, and
maybe even faster," said Mushahwar. "That in itself becomes their
therapy."
Progress can move at a remarkable pace,
yet it's often maddeningly slow.
"There's been an explosion of
knowledge in neuroscience over the last 20 years," Mushahwar said.
"We're at the edge of merging the human and the machine."
Given the nature of incremental funding
and research, a realistic timeline for this type of progress might be close to
a decade.
Mushahwar is the director of the SMART
Network, a collaboration of more than 100 U of A scientists and learners who
intentionally break disciplinary silos to think of unique ways to tackle neural
injuries and diseases. That has meant working with researchers like
neuroscientist Kathryn Todd and biochemist Matthew Churchward, both in the
psychiatry department, to create three-dimensional cell cultures that simulate
the testing of electrodes.
The next steps are fine-tuning the
hardware -- miniaturizing an implantable stimulator -- and securing Health
Canada and FDA approvals for clinical trials. Previous research has tackled the
problem of translating brain signals and intent into commands to the
intraspinal implant; however, the first generation of the intraspinal implants
will require a patient to control walking and movement. Future implants could
include a connection to the brain.
It's the same goal Mushahwar had decades
ago. Except now it's no longer a laughable idea.
"Imagine the future,"
Mushahwar said. "A person just thinks and commands are transmitted to the
spinal cord. People stand up and walk. This is the dream."
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