'New frontier' in therapy helps 2 stroke patients move again – and gives hope for many more

For nearly a decade, Heather Rendulic lived – as she put it – as a one-armed person in a two-armed world. Then, for a month in 2021, she got a respite. 

A stimulator implanted in her neck sent electrical signals into her spinal cord, and she could suddenly control her left hand, which had sat mostly immobile since she suffered a series of strokes in her early 20s.

The first day the implant was turned on, researchers asked her to open and close her hand – and she could.

"My husband and mom were with me. We were in tears and just overjoyed," said Rendulic, now 33. 

Over the course of those four weeks, she got better and better at picking up small blocks, moving them and letting them drop. She drew with her left hand, though she concedes she's "not an artist whatsoever." She ate Chick-fil-A nuggets without her dominant arm. And the best day of all was when researchers bought her a nice juicy steak she could cut on her own.

Rendulic was one of two stroke patients in a pilot clinical trial at the University of Pittsburgh. The results, published Monday in the journal Nature Medicine, mark the first time such stimulation has been used to restore arm and hand movements to people immobilized by stroke. 

The technique, called epidural stimulation, was developed to treat people paralyzed by spinal cord injuries. So far, a small number of people around the world who were told they'd never move their arms or legs again have regained some motion – standing, stepping, even pedaling a bicycle.

But far more people suffer from stroke than spinal cord injury.

More than 5 million Americans live with movement problems after a stroke. The risk of stroke generally rises with age, though some survivors, like Rendulic, are young.

Patients typically get intensive rehabilitation therapy for a few months after a stroke, and improvements come much more slowly after six to 12 months.

But the new research shows electrical stimulation of the spinal cord can return at least some movement control to stroke patients even years later. 

"The science of how this is happening is completely unknown. It's a new frontier," lead researcher Marco Capogrosso said in a call last week with media. "If we manage to understand what exactly is happening in our patients, we can hope to provide this technology to a larger number of patients."

New approach to stroke treatment

After a stroke, even more than spinal cord injury, there's likely to be some signal still passing from the brain to the muscles, said Peter Grahn, an engineer at the Mayo Clinic, who wasn't involved in the study but works in the field and lives with spinal cord injury himself. 

Stimulating the spinal cord below the damage allows messages to get through and restore some – though not perfect – function, he said.

Any motion after years of paralysis will allow stroke patients to benefit from rehabilitation again, said study co-author Elvira Pirondini, who works with Capogrosso at the Spinal Cord Stimulation Laboratory at the University of Pittsburgh School of Medicine.

"It means we can progress faster on the training of these patients," she said, "and get them to a higher level than we can do with any other technology."

In addition to restoring motion, the device seems to allow stroke patients to recover the sensation of where their arms are in space, improving their motor control, she said.

The electrode array, which co-author Douglas Weber described as "kind of like a spaghetti noodle," is implanted on the spinal cord during minimally invasive surgery.  Stimulation delivered from the array strengthens the signal sent from the nerves to the brain.

The stimulator, originally designed to treat pain, is readily available, and the procedures and techniques used to implant the device "are ones that physicians and medical facilities are already very familiar with," said Weber, of Carnegie Mellon University. That should make it feasible to quickly adopt the approach in patients once it has been tested further, he said.

Researchers are now working with more stroke patients to see how to best control the pattern of stimulation, the best placement for the arrays and which patients are best suited for the approach. 

Future potential for stroke patients

The study opens up the possibility of using epidural stimulation well beyond spinal cord injury – in stroke patients as well as people suffering from diseases like Parkinson's, multiple sclerosis and cerebral palsy, several experts said. 

"The general idea of stimulating a remaining pathway where most of the fibers have been injured or destroyed probably would still hold true for many diseases," said Dr. Rose Du, director of cerebrovascular surgery at Brigham and Women's Hospital in Boston, who was not involved in the research. "As long as there are fibers there, I would imagine it doesn't matter what the cause of the injury is."

The stimulation will not restore people to where they were before their stroke, injury or disease, said Grégoire Courtine, a French neuroscientist and co-director of the Defitech Center for Interventional Neurotherapies at École Polytechnique Fédérale de Lausanne in Switzerland.

"It's not a cure," said Courtine, who was not involved in the new study but was Capogrosso's doctoral adviser and has used epidural stimulation on stroke patients in his own research.

"The more significant the damage, the less hope there is for recovery," Courtine said, but the stimulation can help people restore some function.

Moving the stimulation earlier in a patient's course – at a time when dramatic improvements are still possible – should yield even better results than those seen in this trial and others with spinal cord injury patients, said Vivian Mushahwar, a biomedical engineer and director of the sensory motor adaptive rehabilitation technology network at the University of Alberta in Canada.

"This is all basically showing you the art of the possible for conditions that have been around for thousands of years," said Mushahwar, who was not involved in the new research. "People are living longer. We need to be able to provide, as much as possible, better life experiences, if we can."

Although researchers have been exploring epidural stimulation in spinal cord injury patients for decades, it is still not approved for that use.

The small population of people with spinal cord injuries has limited business interest in improving and testing these devices, said Claudi Angeli, who uses stimulation on spinal cord injuries at the University of Louisville in Kentucky.

"This is great to see that somebody has taken it outside of spinal cord injury and done the research to show it works on stroke patients," said Angeli, who was not involved in the new study. "This will hopefully inspire others to start looking at this in more detail as well."

Courtine has started a company, Onward Medical, to pursue regulatory approval for epidural stimulation and bring it out of the realm of research into common use. Courtine said he expects to begin a trial in the United States in about a year.

"It's frustrating that we cannot go faster, but we have a clear path forward," he said.

Regaining independence  

Rendulic was just 22, home for Christmas break from college, when she had her first stroke. She had no family history or prior medical problems, but it turned out she had what's called a cavernous angioma, a malformation in her brain that left her with a cluster of weakened blood vessels.

She was told to just live her life and she'd probably never have another stroke.

Instead, she endured five brain bleeds over the next 11 months. In November 2012, just after her 23rd birthday, she suffered the massive stroke that paralyzed the left side of her body.

In a nine-hour surgery the next month, doctors removed the angioma and resolved her stroke risk.

That's when "I started my journey of regaining my independence," said Rendulic, of Shaler Township, Pennsylvania, about 20 minutes north of Pittsburgh.

Inpatient and then outpatient rehab helped her relearn how to walk, "which was a miracle," but she had very little use of her left hand and arm.

As with most stroke patients, after that first burst of recovery, Rendulic's advances stalled out. 

Then, one day, her mother alerted her to a LinkedIn post from the University of Pittsburgh's neurosurgery department. It was looking for volunteers for a trial of epidural stimulation.

Rendulic met all the criteria for participating.

"I was honored that they picked me to be the first participant," she said. "I had this gut feeling. I knew it was going to be a huge success, and I wanted to be a part of it."

She got the implant in May 2021.

For the month, she spent four hours every weekday in the lab, exploring what she could do and juggling her full-time job as a human resources executive. "It was a very emotional experience," she said. "Every day I almost left in tears – tears of happiness."

At the end of the month she – only half-jokingly – threatened to not show up for the surgery to remove the implant, which was required for her participation in the clinical trial. The use of her left hand lasted a bit longer even when she didn't have the stimulator, but then it faded.

Now, Rendulic looks forward to the day when the stimulator receives regulatory approval and she can get an implant again.

In the meantime, she said, "I'm on a mission to get knowledge of this amazing technology out into the world. It's going to be game changer for millions and millions of people."

(Information on volunteering for the trials can be found here: https://www.rnel.pitt.edu/recruitment/individuals-stroke) 

Contact Karen Weintraub at kweintraub@usatoday.com.

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