Helping stroke patients regain movement in their hands

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Heather Rendulic was 23 when she had a stroke that left her left side disabled. Ten years later, her left arm and hand are so impaired that she cannot tie her shoes, type with two hands, or cut herself a meal.

But for one extraordinary month, while participating in an innovative study, she was suddenly able to open a lock with a key, draw a map of Italy, dip chicken nuggets in sauce, and eat with a fork — all with that left hand. by hand.

“It was like I actually had two arms, oh my god!” Ms. Rendulic said recently.

Researchers from the University of Pittsburgh and Carnegie Mellon University implanted electrodes along her spinal cord, providing electrical stimulation while she tried various activities. With stimulation, she had more mobility in her left hand, more dexterity in her fingers, and could make intentional movements more quickly and fluidly.

The study, published Monday in the journal Nature Medicine, represents the first successful demonstration of spinal cord stimulation to relieve weakness and paralysis in the arms and hands of stroke patients.

The study was small and preliminary, involving only Ms. Rendulic and one other patient. Many scientists said many questions remain about the technique’s effectiveness and applicability, but the research suggested that spinal cord stimulation could eventually help many people who experience stroke.

“I think that has huge implications for improving quality of life,” said Dr. said Lumi Sawaki-Adams, who was not involved in the research. Still, she said, “we have to be careful that we’re not giving 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, the use of stimulation – either via surgically implanted electrodes or non-invasively via electrodes placed on the skin – has been used to help patients with spinal cord injuries regain mobility in their legs. The promise to do is shown, and in some cases, their hands and arms.

But partly because of differences in the location and type of damage, the outlook for stroke has been mostly overlooked, neurological experts said.

Because strokes occur in the brain, it was believed that applying stimulation outside the brain would not provide “the same bang for the buck,” said Arun Jayaraman, executive director of the Center for Technology and Innovation at the Shirley Ryan AbilityLab, a rehabilitation center in Chicago. He said the study, which he was not involved in, contradicts that notion, suggesting instead that stimulating the spine, the pathway from the brain to the arm and hand muscles, may help impaired limbs.

Each year, more than 12 million people worldwide and about 800,000 in the United States experience a stroke, said Dr. Karen Fury, vice chair of the Stroke Brain Health Sciences Subcommittee of the American Stroke Association.

Initially, patients usually get about six months of physical, occupational and other therapies, he said, but then progress often stabilizes.

“We really don’t have anything to offer people who have been out for years and have been disabled for a long time,” said Dr. Furey, chair of neurology at Brown University’s Warren Alpert Medical School and not involved in the study. “

About three-quarters of stroke patients experience loss, weakness or paralysis in their arms and hands, said Dr. Elliott Roth, an attending physician at the Shirley Ryan AbilityLab’s Brain Innovation Center, who was not involved in the study. “For many people, this is the most difficult part of the stroke recovery process and one of the slowest to heal from,” he said.

Patients participating in the study had experienced different types of stroke and had varying degrees of impairment. Ms Rendulic’s stroke was hemorrhagic, caused by a burst blood vessel. The second, more severely impaired patient, a 47-year-old woman who was not identified by the researchers, experienced an ischemic stroke, which is more common and involves blocked blood vessels.

The researchers implanted eight electrode strands at two locations where neurosensory fibers from the arm and hand enter the spinal cord.

Marco Capogroso, an assistant professor of neurological surgery at the University of Pittsburgh, said the approach derived from the fact that with a stroke, some nerve regions remain unaffected.

“So, if we can build on this technology to amplify nerve signals, maybe we have a chance to restore hand and arm movement,” Dr. Capogroso, who led the research along with Elvira Pirondini, assistant professor of physical medicine and rehabilitation. University of Pittsburgh, and Douglas Weber Professor of Mechanical Engineering at Carnegie Mellon’s Neuroscience Institute.

For four hours each day, five days a week, the researchers activated the stimulation, calibrated it to determine the optimal parameters for each patient, and asked them to try different movements and tasks. Its effect was visible in no time.

“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 something that’s really hard for me,” Ms. Rendulic said. As her husband and mother looked on, “I was opening and closing my hand immediately,” she said. “We all broke down in tears.”

Over four weeks, she was given increasingly challenging tasks, such as holding and stirring a soup can. With stimulation, his left hand moved 14 smaller blocks over a box obstacle, compared to six blocks without stimulation.

Typically, when Ms. Rendulik, 33, who works at home for a company’s human resources department, tries to do something like hold a pen with her left hand, her hand feels like “it’s made of rock.” is,” his brain was almost disconnected, she said. With excitement “It was like my brain was able to find my left hand that much easier.”

Another patient, who was given simple tasks because his left arm was almost completely paralyzed, improved skills such as reaching.

The researchers also tested a “sham” stimulus, activating the electrodes at random to see if patients responded to a sort of placebo effect, rather than a stimulus specifically targeted to their hands and arms. Both did better with targeted stimulation.

The researchers reported that the patients felt the stimulation, but it did not cause pain, stiffness or safety concerns.

The approved study protocol required removal of the electrodes after 29 days. But a month later, the patients retained some of the improved abilities, surprising researchers. “We thought it was not possible” after only four weeks of stimulation, Dr Pirondini said.

It’s not clear why the benefit may persist, Dr. Capogroso said, but he hypothesized that “the same neural processes that allow these people to use this stimulation method also lead to movement recovery when the stimulation is turned off.” “We’re not making new fibers, but we’re definitely strengthening what’s there,” he said.

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 important skills in daily life?

“It’s the first step among hundreds,” said Dr. Daniel Lu, who co-authored a 2016 study showing that spinal cord stimulation from implanted electrodes improved hand strength and control. in two patients with spinal cord injury.

Doctor. Lu said he believes stimulation is promising, but it was difficult to evaluate its effect in the new study because there was no comparison group and patients were not given the same regimen of intense activities before stimulation. Activities that may have therapeutic benefits in themselves.

“Is it possible that you are only exercising the patient, and without the stimulation the patient would have received the same effect?” He asked.

Another question neuroscientists raise is whether — or under what circumstances — it is better to surgically implant electrodes or place them on the skin, a less expensive method called transcutaneous stimulation. The authors of the new study consider surgical implantation to be preferable because it is “more specific,” Dr. “Allows us to target the muscles that control the wrist and hand,” Weber said.

Others, such as Chet Moritz, professor of neurotechnology at the University of Washington, have reported improvements in spinal cord injury patients using electrodes on the skin, including benefits that last for months after the stimulation has ended. “It’s true that we can’t tune the shoulder to this degree and the elbow to this degree and the wrist to that degree, but the nervous system seems to take care of that for us,” he said.

Many neurological experts predict that both methods may ultimately be helpful and appropriate for different patients depending on their health and other factors. All the experts, including the study authors, said stimulation would be more effective if accompanied by rehabilitation therapies.

The study authors said their ongoing research is evaluating patients of varying stroke severity, age and other characteristics to determine who would benefit most from their approach. They’ve formed a company and say they envision that with similar technology for chronic pain, patients could adjust their stimulation via an app or remote control.

If stimulation became routinely available for stroke patients, Ms Rendulic would welcome it. “I threatened not to show up for surgery to have it removed,” she said. “I wanted it all the time.”

While she has devised one-handed ways to perform activities such as driving and typing, everyday frustrations, such as needing her husband Mark, whom she calls “my left-handed man”, to slice steak for her For.

“In testing, I got a steak bite, which was awesome,” she said. Then, fork in his left hand, he speared a spear and lifted it up to his mouth—one previously impossible feat at a time.

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