Spinal cord stimulation improved arm mobility and reduced spasticity in stroke survivors during a pilot clinical trial.
The study tested whether an implanted electrical stimulation device could improve arm and hand movement in people living with chronic stroke.
The trial was mainly designed to assess safety and early signs of effectiveness.
It found that seven participants with severe muscle weakness after stroke had an average 32 per cent increase in arm strength, along with improved overall arm mobility and reduced muscle spasticity.
Researchers said the intervention involved fewer than nine hours of movement-based training over four weeks and did not cause discomfort or serious adverse events.
Marco Capogrosso, co-senior author, assistant professor of neurological surgery at Pitt and director of the spinal cord stimulation laboratory at Rehab Neural Engineering Labs in the UPMC Rehabilitation Institute, said: “This approach is designed to rapidly help people move their arms better, even years after a stroke.
“The stimulation works mostly as an assistive technology, when it’s on, people can move better.
“By stimulating the spinal cord, we can immediately allow residual connections between the brain and the spinal cord to work more efficiently, enabling better movement.”
Stroke is the leading cause of adult arm paralysis in the US, with around 400,000 people developing chronic arm and hand weakness each year.
Many stroke survivors rank recovery of arm function as their top unmet clinical need, but standard rehabilitation rarely leads to meaningful improvement.
To address this gap, researchers launched a pilot clinical study to test whether epidural spinal cord stimulation delivered to the region controlling arm and hand movement could help stroke survivors regain arm function.
The project was named among one of the most significant innovations supported by the National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, in its 75th anniversary report.
The trial tested cervical epidural spinal cord stimulation, which involves implanting thin electrodes along the neck region of the spinal cord.
The cervical spine is the neck section of the spine, while epidural means the device sits near the spinal cord rather than inside it.
The stimulation sends targeted electrical signals to sensory nerve fibres in the spinal cord to improve communication between the brain and weakened muscles.
The same type of device has been used for decades to treat chronic pain, but researchers said this is the first time it has been used to restore arm function after stroke.
The study expands on earlier findings reported by the team in 2023 and confirms that the approach is safe and feasible across participants of different ages, sexes and racial backgrounds.
Researchers observed two distinct types of benefit.
Over the four-week study period, all seven participants had immediate improvements in strength when stimulation was turned on, regardless of how severe their impairment was at the start of the study.
Spasticity, which is abnormal muscle stiffness caused by stroke-damaged nerve pathways, was also reduced in all seven participants.
George Wittenberg, study co-author and professor of neurology and physical medicine and rehabilitation at Pitt’s School of Medicine, said: “From a clinical perspective, even modest improvements in arm strength or control can make a meaningful difference in daily life of stroke survivors.
“Some of the improvements we measure may look small from the outside, but many stroke survivors are just on the verge of being able to do something important.
“Even a small change in motor function can be very significant if it helps someone button a shirt, open their hand or return to an activity they care about.”
Although some improvements appeared immediately, researchers found that lasting gains depended on continued use of stimulation.
Follow-up assessments showed that motor function declined when stimulation was stopped.
The team said this underlines the potential of spinal cord stimulation as an assistive neuroprosthetic technology rather than a short-term rehabilitation aid.
A neuroprosthetic is a device that supports or replaces lost nervous system function.
Capogrosso said: “This study represents the conclusion of our initial feasibility phase and an important step toward real-world clinical application.
“Our goal is to develop a technology that could eventually be used in everyday life, not just in the clinic.
“These results give us confidence that spinal cord stimulation could become a practical, implantable option for helping stroke survivors use their arms when it matters most.”
The research team has begun recruiting participants for a longer clinical trial to assess spinal cord stimulation over a longer period, both alone and alongside physical therapy.
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