In test, zaps to spine help 2 stroke survivors move arms
A stroke left Heather Rendulic with little use of her left hand and arm, putting certain everyday tasks like tying shoes or cutting foods out of reach.
“I live one-handed in a two-handed world and you don't realize how many things you need two hands for until you only have one good one,” the Pittsburgh woman told The Associated Press.
So Rendulic volunteered for a first-of-itskind experiment: Researchers implanted a device that zaps her spinal cord in spots that control hand and arm motion. When they switched it on, she could grasp and manipulate objects — moving a soup can, opening a lock and by the end of the four-week study, cutting her own steak.
It's not a cure — the improvements ended after scientists removed the temporary implant — and the pilot study included only Rendulic and one other stroke survivor. But the preliminary results, published Monday, mark a step toward one day restoring mobility for this extremely common type of paralysis.
“They're not just getting flickers of movement. They're getting something important,” said Dr. Jason Carmel, a Columbia University neurologist who wasn't involved with the new experiment but also studies ways to recover upper-limb function. “It's a very exciting proof of concept.”
Nearly 800,000 people in the U.S. alone suffer a stroke each year. Even after months of rehabilitation, well over half are left with permanently impaired arm and hand function that can range from muscle weakness to paralysis.
Experiments by multiple research groups have found that implanting electrodes to stimulate the lower spine shows promise for restoring leg and foot movement to people paralyzed after a spinal cord injury — some have even taken steps.
But upper-limb paralysis has gotten little attention and is inherently more challenging. The brain must signal multiple nerves that control how the shoulder lifts, the wrist turns and the hand flexes. Stroke damage makes it harder for those messages to get through.
“People still retain some of this connection, they're just not enough to enable movement,” said University of Pittsburgh assistant professor Marco Capogrosso, who led the new research with colleagues at Carnegie Mellon University. “These messages are weaker than normal.”
His idea: Stimulate a pathway of related nerve cells so they're better able to sense and pick up the brain's weak signal.