![]() ![]() ![]() With the new, larger implant and custom-positioned electrodes, all three could take steps on a treadmill within the first day after the stimulation was turned on-albeit with harnesses that supported more than half of their weight, the team reports today in Nature Medicine. ![]() But the participants in the new study had more severe, complete injuries, all of which occurred at least 1 year before their enrollment. In 2018, this patterned stimulation approach got a big test: People with spinal cord injuries who had some residual leg sensation or movement were able to walk and cycle. But just how the electrical stimulation interacts with spinal networks, and in turn the relative advantages of the two approaches, aren’t clear yet, he adds. Patterned stimulation might help retrain damaged networks of nerves in the spinal cord to better receive and interpret signals descending from the brain that are preserved after spinal cord injury, he says. Typical epidural implants deliver uniform, repetitive pulses of electricity, says Peter Grahn, a neuroscientist at the Mayo Clinic. Once they had the new design, they used computer models to predict the ideal position of the implant on each patient’s spinal cord.įinally, the team designed software to activate the electrodes in set patterns that produce movements such as standing up and stepping. To position electrodes along its surface so they would precisely stimulate the dorsal roots, the researchers studied cadavers and images of healthy spines. So he and his colleagues designed a longer and wider implant, roughly the size of a pointer finger. Existing electrode strips are also too short to reach the dorsal roots that control the trunk and enable bending and straightening the torso, Courtine says. To trigger leg and torso movements, researchers need to stimulate the dorsal roots, pairs of thick sensory fibers extending from either side of the spinal cord. One problem with existing implants is their shape: They consist of a narrow silicone strip that targets the center of the spinal cord to disrupt pain signals ascending to the brain. When such stimulation is turned on, even some patients with “complete” paraplegia-no movement or sensation in the lower body-have been able to walk after extensive training and with assistance from supportive devices or a therapist.īut spinal cord stimulators, developed in the 1980s to treat chronic pain, weren’t designed with spinal cord injury in mind, says Grégoire Courtine, and neuroscientist at the Swiss Federal Institute of Technology, Lausanne. But epidural stimulation devices, thin sheets of electrodes implanted beneath the vertebra of the lower spine, can re-create those commands beyond the injury site and trigger leg movements. When trauma severely damages the bundle of nerves that make up a person’s spinal cord, the brain’s electrical signals no longer reach the body’s muscles, resulting in paralysis. “This adds a level of refinement that allows for these approaches … to make it to the clinic and hopefully help a large number of people.” “This I would call a big deal,” says Vivian Mushahwar, a biomedical engineer and neuroscientist at the University of Alberta, Edmonton, who was not involved in the work. The nerve-stimulating device doesn’t cure spinal cord injury, and it likely won’t eliminate wheelchair use, but it raises hopes that the assistive technology is practical enough for widespread use. The men, who had no sensation or control over their legs, were able to take supported steps within 1 day of turning on the electrical stimulation, and could stroll outside with a walker after a few months, researchers report today. Three men paralyzed in motorcycle accidents have become the first success stories for a new spinal stimulation device that could enable faster and easier recoveries than its predecessors. ![]()
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