Spinal cord stimulation restores movement years after stroke
Published in Nature Medicine, researchers demonstrate that targeted spinal cord stimulation can significantly improve arm and hand function in people living with chronic stroke, even years after their injury.
After years of exploring how spinal cord circuits can be harnessed to restore movement, Carnegie Mellon University researchers in collaboration with The University of Pittsburgh have helped demonstrate a major milestone in stroke rehabilitation. New findings published today in Nature Medicine show that targeting spinal cord stimulation can improve strength, mobility, and dexterity in people living with chronic stroke, even years after their injury.
The study reports the final results of a pilot clinical trial that evaluated cervical epidural spinal cord stimulation, a neurotechnology designed to restore movements by strengthening communication between the brain and weakened muscles. Across seven participants with chronic stroke-related arm paralysis, researchers observed immediate improvements in strength, dexterity, and mobility, along with reductions in muscle spasticity. Participants experienced an average 32% increase in arm strength after just four weeks of treatment and less than nine hours of movement-based training.
The findings build on results first reported in 2023 that demonstrated that spinal cord stimulation could restore arm and hand movement in two stroke survivors. The new study expands those findings across a larger and more diverse group of participants, confirming the approach is safe, feasible and effective for individuals with varying degrees of impairment.
“This approach is designed to rapidly help people move their arms better, even years after a stroke,” said co-senior author Marco Capogrosso, 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. “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.”
Researchers from CMU’s Department of Mechanical Engineering and Neuroscience Institute played a key role in developing the neurotechnology and advancing the understanding of how spinal cord circuits can be engaged to restore movement after neurological injury. The team developed the technology that uses thin electrodes implanted along the cervical region of the spinal cord. These electrodes deliver targeted electrical stimulation to sensory nerve fibers, which increase the responsiveness of the spinal cord circuits that translate signals from the brain into movement.
“The nervous system often retains pathways that survive the stroke, but those connections are too weak to generate functional movement,” said Doug Weber, professor of mechanical engineering and neuroscience at Carnegie Mellon and co-senior author of the Nature Medicine paper. “By stimulating sensory circuits in the spinal cord, we can amplify those remaining signals and help people access movement that would otherwise be difficult or impossible to perform.”
Unlike traditional rehabilitation approaches that seek to gradually improve function over months of therapy, spinal cord stimulation produced immediate benefits when activated. Participants showed stronger movements, improved arm dexterity and reduced spasticity while stimulation was turned on. Several participants were able to perform functional tasks that had previously been difficult or impossible, including reaching, grasping and moving everyday objects.
Researchers also found that the greatest benefits occurred while the stimulation was actively being delivered, highlighting the technology’s potential as an assistive neuroprosthetic that could one day be used during daily activities.
By bringing together expertise in neuroscience, rehabilitation medicine, and neurotechnology we’re able to translate findings in the lab into impactful solutions for daily life.
Doug Weber, Professor, Mechanical Engineering
“Our goal is to develop systems that integrate seamlessly into daily life to help people regain independence in the activities that matter most to them,” said Weber. “This study shows the potential of spinal cord stimulation not only as a rehab tool, but as a practical technology that can assist when and where it is needed.”
Weber emphasized that a key reason this technology has been able to advance is because of the close, continuous collaboration between engineering and clinical teams.
“By bringing together expertise in neuroscience, rehabilitation medicine, and neurotechnology we’re able to translate findings in the lab into impactful solutions for daily life,” Weber said. “We created Reach Neuro, Inc., to ensure that this new therapy can be made available to the millions of Americans living with disabilities due to stroke and other neurological disorders.”
Moving forward, the research team has begun recruiting participants for expanded clinical trials to evaluate longer-term use of spinal cord stimulation and to explore how the technology can be combined with rehabilitation theory to maximize recovery.
In addition to Carnegie Mellon and the University of Pittsburgh, collaborators included researchers from Columbia University, the Veterans Affairs Pittsburgh Healthcare System and Johns Hopkins University.
This research was supported by the National Institutes of Health BRAIN Initiative (grant
UG3NS123135‑01A1), internal funding from the departments of Neurological Surgery and Physical Medicine and Rehabilitation at Pitt, as well as the Department of Mechanical Engineering and the Neuroscience Institute at Carnegie Mellon University.
The project was named among one of the most significant innovations supported by the National Institute of Neurological Disorders and Stroke (NINDS) in their 75th anniversary report.