Heather Rendulic was 23 years old when she suffered a disabling stroke on her left side. Ten years later, her left arm and hand are still so damaged that she can’t tie her shoes, type with two hands, or cut her own food.
But during one extraordinary month, while participating in a groundbreaking study, he was suddenly able to open a lock with a key, draw a map of Italy, dip a chicken nugget in sauce, and eat it with a fork, all with his left hand.
“It was like he had two arms, oh my gosh!” Ms. Rendulic recently said.
Researchers from the University of Pittsburgh and Carnegie Mellon University implanted electrodes along their spinal cord, providing electrical stimulation as they attempted different activities. With stimulation, her left arm was more mobile, her fingers were more dexterous, and she was able to make intentional movements more quickly and fluently.
the study posted on monday in the journal Nature Medicine, represents the first successful demonstration of spinal cord stimulation to treat paralysis in the arms and hands of stroke patients.
The study was small and preliminary, involving only Ms Rendulic and one other patient. Several scientists said many questions remain about the effectiveness and applicability of the technique, but that the research suggested that spinal cord stimulation could eventually help some of the many people who experience strokes.
“I think there are huge implications for improving quality of life,” said Dr. Lumy Sawaki-Adams, program director in the division of clinical research at the National Institute of Neurological Disorders and Stroke, who was not involved in the research. Still, she said, “we have to be careful not to offer hope to too many people when I think we’re not there yet.”
Spinal cord stimulation has been used for decades to treat chronic pain. More recently, experiments that provide stimulation, either through surgically implanted electrodes either non-invasively through electrodes placed on the skin — have shown promise in helping spinal cord injury patients regain mobility in their legs and, in some cases, their arms and hands.
But the approach hasn’t been explored for the most part for stroke, in part because of differences in the location and type of damage, the neurology experts said.
Because strokes occur in the brain, applying stimulation outside the brain was not supposed to provide “the same investment,” said Arun Jayaraman, executive director of the technology and innovation center at Shirley Ryan AbilityLab, a rehabilitation center . In Chicago. He said the study, in which he was not involved, countered that assumption, suggesting instead that stimulating the spine, the pathway from the brain to the muscles in the hands and arms, could help damaged limbs.
Every year, more than 12 million people around the world other nearly 800,000 in the United States experience strokes, said Dr. Karen Furie, vice chair of the American Stroke Association’s subcommittee on stroke brain End-shutdown sciences.
At first, patients typically receive about six months of physical, occupational and other therapies, he said, but then progress often stalls.
“We have virtually nothing to offer to people who have been through years and have long-standing disabilities,” said Dr. Furie, who is also chair of neurology at Brown University Warren Alpert School of Medicine and was not involved in the study.
About three-quarters of stroke patients experience impairment, weakness or paralysis in the arms and hands, said Dr. Elliot Roth, an attending physician at the Shirley Ryan AbilityLab’s Brain Innovation Center, who was not involved in the study. . “For many people, it is the most difficult part of the stroke recovery process and they tend to recover more slowly,” he said.
The patients who participated in the study had experienced different types of strokes and had varying degrees of impairment. Ms. Rendulic’s stroke was hemorrhagic, caused by ruptured blood vessels. The other more severely disabled patient, a 47-year-old woman whom the researchers did not identify, experienced an ischemic stroke, which is more common and involves blocked blood vessels.
The researchers implanted eight-electrode leads in two locations, corresponding to where neurosensory fibers from the arm and hand enter the spinal cord.
Marco Capogrosso, an assistant professor of neurological surgery at the University of Pittsburgh, said the approach stems from the fact that with strokes, some neural areas remain intact.
“So if we can build this technology to amplify neural signals, we may have an opportunity to restore movement of the arm and hand,” said Dr. Capogrosso, who led the research with Elvira Pirondini, an assistant professor of physical medicine and rehabilitation at the University of Pittsburgh, and Douglas Weber, a professor of mechanical engineering at the Carnegie Mellon Neuroscience Institute.
Five days a week for four hours each day, the researchers turned on the stimulation, calibrated it to determine the optimal settings for each patient, and asked them to try various movements and tasks. Immediately, the effect was noticeable.
“The first day in the lab and the first time they turned it on, I was sitting in a chair and they asked me to open and close my hand, and that’s a really hard thing for me,” said Ms Rendulic. As her husband and her mother watched, she “was immediately clenching her hand,” she said. “We all burst into tears.”
Over four weeks, he was given increasingly challenging tasks, such as picking up and moving a can of soup. With stimulation, her left hand moved 14 small blocks over a barrier in a box, compared to six blocks without stimulation.
Usually when Ms Rendulic, 33, who works at home for a company’s human resources department, tries to make her left hand do something like grab a pen, her arm feels like it’s “made of rock”, almost disconnected from his brain. she said. With the stimulation, “it was like my brain could find my left arm a lot easier.”
The other patient, who was given easier tasks because her left hand was almost completely paralyzed, improved in skills such as reaching.
The researchers also tested a “sham” stimulation, activating electrodes at random to see if the patients responded to a kind of placebo effect rather than stimulation directed specifically to their arms and hands. Both performed better with targeted stimulation.
The patients felt the stimulation, but it did not cause pain, stiffness or safety concerns, the researchers reported.
The approved study protocol called for electrode removal after 29 days. But a month later, the patients retained some improved abilities, surprising the researchers. “We thought it was not possible” after just four weeks of stimulation, Dr. Pirondini said.
It’s not clear exactly why the benefit may persist, Dr. Capogrosso said, but he hypothesized that “the same neural processes that allow these people to use this method of stimulation also lead to movement recovery when stimulation is on.” deactivated”. He added, “We’re not creating new fibers, but we’re definitely restricting what’s out there.”
Several experts noted that this pilot study was not designed to answer the most relevant question for patients: Can improvements in laboratory tasks translate into skills that matter in daily life?
“It’s one step among hundreds,” said Dr. Daniel Lu, professor and vice chair of neurosurgery at the University of California, Los Angeles, co-author a 2016 study which showed that spinal stimulation from implanted electrodes improved hand strength and control in two patients with spinal cord injury.
dr. Lu said he believes the stimulation is promising, but its impact in the new study was difficult to assess because there was no comparison group and the patients did not receive the same regimen of intensive activities before the stimulation, activities that could have a therapeutic benefit.
“Is it possible that you are just exercising the patient and the patient without the stimulation would have gotten the same effect?” she asked.
Another question neuroscientists raise is whether, or under what circumstances, it is better to implant electrodes surgically or place them on the skin, a less expensive method called transcutaneous stimulation. The authors of the new study believe that surgical implantation is superior because it is “much more specific,” Dr. Weber said, allowing it to “target the muscles that control the wrist and hand.”
Others, like Chet Moritz, a professor of neurotechnology at the University of Washington, have reported improvements in patients with spinal cord injuries. use of electrodes on the skin, including benefits that last for months after stimulation ends. “It’s true that we can’t tune the shoulder to this degree, the elbow to this degree, and the wrist to that degree, but the nervous system seems to take care of that for us,” she said.
Several neurological experts predicted that both methods could eventually be useful and appropriate for different patients, depending on their End-shutdown and other factors. All the experts, including the authors of the study, said that the stimulation would be more effective if it is accompanied by rehabilitation therapies.
The study authors said their ongoing research is evaluating patients of different stroke severity, age and other characteristics to determine who would benefit from their approach. They formed a company and said they envision that, as with similar technology for chronic pain, patients could adjust their stimulation via an app or remote control.
If stimulation is regularly available for stroke patients, Ms Rendulic would appreciate it. “I threatened not to show up for surgery to have it removed,” she said. “I just wanted it all the time.”
Though she’s devised ways to do one-handed activities like driving and typing, everyday frustrations irritate her, like needing her husband Mark, whom she calls “my left hand,” to cut up a steak for her.
“In the test, I was able to cut through a steak, which was amazing,” he said. Then, with the fork in his left hand, he cut off a piece and raised it to his mouth, a movement that was previously impossible at once.