Nerve stimulation therapy shows promise for spinal cord injury recovery
A new therapy combining electrical nerve stimulation with physical rehabilitation has led to significant improvements in arm and hand function for people with spinal cord injuries.
The treatment, known as closed-loop vagus nerve stimulation (CLV), uses a small device implanted in the neck that delivers electrical pulses to the brain during targeted rehabilitation exercises.
Researchers at the Texas Biomedical Device Center (TxBDC), part of the University of Texas at Dallas, tested the approach on 19 participants with chronic, incomplete cervical spinal cord injuries – damage to the upper spine in which some nerve connections remain intact.
Participants, aged between 21 and 65 and between one and 45 years post-injury, completed a 12-week therapy programme involving video games designed to prompt specific upper-limb movements.
The implanted device delivered stimulation when those movements were successfully performed.
Dr Michael Kilgard is professor of neuroscience and corresponding author of the study.
The researcher said: “In stroke, people who do only therapy may get better, and adding CLV multiplies that improvement.
“This study is different: Therapy alone for spinal cord injury didn’t help our participants at all. It is truly groundbreaking that we’re creating a gain where there otherwise would be none.”
The trial served as both a Phase 1 and Phase 2 study and included a randomised placebo-controlled element.
Nine of the 19 participants received sham stimulation – where the device was implanted but not activated – for their first 18 therapy sessions, then switched to active CLV for the next 18.
All participants completed 36 sessions of intensive rehabilitation at a rate of around three per week.
Researchers reported that neither age, time since injury, nor severity of impairment in those with any hand movement affected how well participants responded to the therapy.
Dr Jane Wigginton is a medical doctor and chief medical officer at TxBDC, and medical science research director at the Center for BrainHealth.
She said: “This approach produces results regardless of these factors, which often cause significant differences in success rates of other types of treatment.”
The current version of the CLV device is about 50 times smaller than the version used three years ago. It does not interfere with MRI, CT or ultrasound scans.
Dr Robert Rennaker, professor of neuroscience and the device’s designer, said: “These activities allow patients to regain strength, speed, range of motion and hand function.
“They simplify daily living.”
Vagus nerve stimulation has already been approved by the US Food and Drug Administration for treating impaired upper-limb movement following stroke, based on 13 years of TxBDC research.
Dr Wigginton said the latest results were especially meaningful for people with few other options:
The researcher said: “I can’t overemphasise how satisfying it is as a physician to give hope and help to these spinal cord injury patients, who would come in with all kinds of complications and hopelessness.
“The people in this study have now gained the ability to do things that are meaningful for them and impactful in their lives.”
A Phase 3 pivotal trial is planned, involving 70 participants across multiple US centres that specialise in spinal cord injury.
However, Dr Seth Hays, associate professor of bioengineering, warned that challenges remain.
He said: “We still have a long road ahead. For many reasons — financial, regulatory or scientific — this could still die on the vine. But we have positioned ourselves to succeed.”
