Two Stroke Patients Regain Hand Movement Due to Novel Stimulation Therapy
Electrospinal stimulation of dormant neurons in the spinal cord has restored hand movement in stroke patients in a first-of-its-kind experiment.
Two stroke victims who received spinal cord electrical stimulation temporarily recovered some mobility in their arms, according to a study published in Nature Medicine. Weakened connections between their upper limbs, brain, and spinal cord were temporarily repaired after they underwent an experimental technique described as feeling "like a tickling."
According to the Centers for Disease Control and Prevention (CDC), around 795,000 Individuals will have a stroke yearly. Stroke is the top cause of mortality in the United States and the main cause of paralysis. A stroke occurs when blood flow to an area of the brain suddenly stops. Around one in four individuals worldwide will have a stroke at some point in their lives. It has the potential to permanently degrade brain impulses to the point where neurons in the spinal cord are unable to perceive them and therefore are unable to activate movement.
Muscle weakness or paralysis, especially affecting the use of the arms and hands, is a typical long-term consequence for those who do survive. They may have serious consequences for persons who experience them, affecting their independence in many areas of life.
Experiments conducted by a number of different research groups have found that the implantation of electrodes to stimulate the lower spine shows promise for restoring leg and foot movement to people who have been paralyzed due to a spinal cord injury. Some of these individuals have even been able to take their first steps since becoming paralyzed.
The brain must send signals to a number of nerves in order to elevate the shoulder, move the wrist, and flex the hand. Damage caused by a stroke makes it more difficult for such signals to be received. Nonetheless, upper-limb paralysis has received very little study, even though it is fundamentally more difficult.
"People still maintain some of this link, but they're simply not enough to permit movement," said assistant professor Marco Capogrosso of the University of Pittsburgh, who conducted the new study with colleagues from Carnegie Mellon University.
He planned to stimulate a network of connected nerve cells to improve their capacity to detect and take in the brain's weak signal.
He and his colleagues performed surgery and implanted eight electrical nodes on each side of the spinal cords of two patients with upper body paralysis due to a stroke. According to him, this procedure is a minimally invasive operation in which a catheter is used to thread eight linked electrodes through a puncture about the size of spaghetti.
Four days after implanting the electrodes, they used electrical stimulation to increase the sensitivity of the neurons in the spine that controlled arm movement to messages coming from the brain.
The participants were given activities to do five days a week for a period of four weeks to measure arm strength, mobility, and function. The first subject, Heather Rendulic, cannot tie shoes or chop food due to limited use of her left hand and arm, experienced a 40% increase in hand grip strength when the electrodes were turned on, whereas the second participant saw a 108% increase in hand grip strength when the electrodes were turned on. When the stimulation was turned off, neither of them was able to reach certain things, but when they were in a virtual reality setting.
When the stimulation was turned on, the first participant could also unlock a lock and use utensils to eat independently for the first time in nine years. This was a significant improvement. The second participant was unable to execute these activities due to the severity of her paralysis, but she was able to grip, raise, and position a metal cylinder onto a wooden peg, which she could not do without stimulation.
According to Capogrosso, "What we didn't anticipate was that part of this recuperation would stay even after the stimulation was stopped." The participants were given a 66-point scale evaluation to complete before the research and again four weeks after completing their most recent stimulation. This evaluation examined the individuals' motor recovery. The first participant's score went up by 11 points, while the second participant's score went up by 2.
As reported by ABC News, It's not a cure; the gains stopped after the temporary implant was removed, and the pilot research only involved Rendulic and one other stroke victim. But, the early findings represent an important step toward one day regaining movement for a highly frequent kind of paralysis.
“They’re not just getting flickers of movement. They’re getting something important,” said Dr. Jason Carmel, a Columbia University neurologist who was not involved in the latest study but is also researching strategies to regain upper-limb function. “It’s a very exciting proof of concept.”