ReDISCOVER
Next Steps
A scientist’s prediction of a paralysis cure delivers mixed results.
IN 2009,
DISCOVER reported
that University
of Washington
physiologist Chet
Moritz had made
serious strides toward
curing paralysis. He
and his colleagues
figured out a way
to record and transfer signals from a
macaque’s brain to its paralyzed arm,
bypassing its injured nerves, and allowing
the monkey to control its limb once more.
Challenges remained, but Moritz told
Discover he thought advances in these
technologies could provide an answer to
paralysis in as little as 10 years. Well, it’s
2019 — was he right?
Yes and no. Three different research
groups have recently announced that
they’ve achieved the first independent
walking steps taken by patients with
spinal cord injuries. But the groups, all
unaffiliated with Moritz, didn’t do it his way.
Instead, the teams
figured out how to coax
the injured nerves to
work on their own using
“epidural stimulation”
— electrical pulses
delivered directly to
the spinal cord.
These pulses don’t
give the limbs specific
instructions; rather, the electricity provides
the existing nerves the boost they need to
let the brain communicate naturally to the
paralyzed limb. It’s an approach that could
help treat paralysis cases where some
nerve connections remain — about 90
percent of people with spinal injuries.
For the 10 percent of people with a
completely severed spinal cord, Moritz’s
method may still be the best path forward,
since it bypasses the need for any nerve-
based communication. But, he says, the
type of biomedical device required for
reading and understanding brain signals is
not quite ready.
“If I had known [in 2009] what I know
now about implanted medical devices,
I would’ve said more than 10 years,”
says Moritz.
Epidural stimulation is promising;
besides improved mobility, some patients
also regained bladder/bowel control and
even some sexual function. And Moritz’s
own explorations of spinal electrical
stimulation have shown it has similar
effects on paralyzed arms, not just legs.
But he emphasizes that we haven’t “cured”
paralysis. “I think it’s important to call
it stepping, as opposed to walking,” he
says. “They’re not walking away from their
wheelchair with their hands on nothing,
with no body weight support, with no
balance aids.” Researchers still need to
work on restoring the quick, smooth gait
we typically picture as walking.
“So that can be my next 10-year
prediction,” says Moritz. “Ten years from
now, we’ll have people walking as if they
didn’t have a spinal cord injury before.”
We’ll see what 2029 brings. — ANNA GROVES
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Nerve stimulation, and other tech, can now allow once-paralyzed patients to take steps.