Spinal implant helps stroke patients regain arm mobility

A spinal implant helped seven stroke survivors improve arm and hand mobility during a four-week pilot clinical trial, researchers found.

Participants had profound movement impairments and received electrical stimulation alongside less than nine hours of painless movement training.

All seven experienced improvements regardless of their initial level of mobility.

The University of Pittsburgh-led team reported an average 32 per cent increase in arm strength, along with better overall arm mobility and reduced abnormal muscle stiffness caused by damaged nerve pathways.

Study co-authors Marco Capogrosso, director of the spinal cord stimulation laboratory at UPMC Rehabilitation Institute and associate professor of neurological surgery at the University of Pittsburgh, and George Wittenberg, professor of neurology and physical medicine and rehabilitation, said the device could make physical rehabilitation less daunting by providing more immediate results.

The effects of rehabilitation typically slow dramatically after six months, according to Johns Hopkins.

“It is like a quantum change in the way that stroke rehabilitation is being handled,” Wittenberg said.

“The nervous system is damaged in certain ways that no amount of practice will actually heal the nervous system and make you better able to use what you have. This adds to that in a huge way.”

During the pilot, patients received cervical epidural spinal cord stimulation, where thin electrodes were implanted along the neck near the part of the spinal cord involved in arm and hand movement.

Electrical signals are sent to sensory nerve fibres in the spinal cord to improve communication between the brain and weakened muscles and help restore some control.

The approach has been used for decades to treat chronic pain and is currently approved by the US Food and Drug Administration for pain management, but the researchers said it had not previously been used to restore arm function following a stroke.

“Normally the way we move is that our brain sends signals to some neurons in the spinal cord that then eventually control the muscles,” said Capogrosso.

“After a stroke, those signals get substantially diminished.”

Capogrosso said the technology is intended to amplify the signals that remain.

“We’re not substituting anything. We’re just trying to facilitate whatever is left after stroke and help it as much as we can.”

If proven effective, the approach could help some of the approximately 400,000 people who develop chronic arm and hand weakness following stroke each year in the US, according to the American Heart Association.

“We’re seeing more acceptance of devices that are implanted surgically,” Wittenberg said.

“And so I think as there’s acceptance of that and that it’s not such a big step. People already get pacemakers to keep their heart going, so why not have a spinal cord stimulator to keep their movement going?”

Capogrosso said the immediate effect of stimulation could also help motivate people during rehabilitation.

“If I turn this on, you’re gonna be better and you will see that. That will serve as some motivation,” he said.

“People start engaging more in activity because they turn it on and they can move around better.”

Researchers said the initial study, which focused on safety and feasibility, indicated that maintaining gains may depend on continued stimulation, with motor function declining after stimulation stopped.

“My goal was in the beginning to be able to hug my girlfriend and daughter with both arms,” said Signorini.

“I was able to do that.”

Capogrosso said working directly with participants had reinforced the importance of continuing the research.

“When you see that [progress] is happening, you quickly realize that you owe it to the patients to continue,” said Capogrosso.

He said the work becomes focused on the people taking part rather than simply producing research findings.

“It becomes about them. So it’s very important to keep doing this because you really see how you can change hope for a lot of people.”

The researchers are now recruiting for a longer clinical trial examining extended spinal cord stimulation both on its own and alongside physical therapy.

Capogrosso said he believes the technology could be approved for use in people recovering from stroke within three to five years if no major obstacles emerge.