Five men with complete motor paralysis were not only able to move their legs again, but they achieved this amazing feat with a non-invasive procedure. By delivering electrical stimulation to the men’s spinal cords, researchers were able to help the paralyzed men voluntarily move their legs in a walking motion.
The remarkable study, published the Journal of Neurotrauma, was built on previous research that also used electrical stimulation. Within a year, researchers were able to massively develop their technique. At first, they surgically implanted a device – called an epidural stimulator – on the surface of the men’s spinal cords. Eventually, they developed a non-invasive alternative where researchers were able to electrically activate the spinal circuitry by placing electrodes on the skin of the lower back. The new technique is called transcutaneous electrical nerve stimulation.
“There are a lot of individuals with spinal cord injury that have already gone through many surgeries and some of them might not be up to or capable of going through another,” said Edgerton in a statement. “The other potentially high impact is that this intervention could be close to one-tenth the cost of an implanted stimulator.”
Each of the men, who were paralyzed for more than two years, had to undergo 45-minute stimulation sessions once a week for 18 weeks. This was combined with the pharmacological drug buspirone in the final four weeks of treatment. Buspirone, which mimics the neurotransmitter serotonin, has previously been shown to induce walking motions in mice with spinal cord injuries. By the end of the study, the paralyzed men were able to move their legs without stimulation.
“It’s as if we’ve reawakened some networks so that once the individuals learned how to use those networks, they become less dependent and even independent of the stimulation,” said Edgerton.
Researchers note that for now the action is not comparable to walking. While movement did occur, their legs were suspended in braces that hung from the ceiling. This allowed them to move their legs without the resistance from gravity. Researchers want to go on to investigate whether these same men would be able to fully support their own weight with non-invasive spinal stimulation, which they have already achieved with the four men who had surgically implanted stimulators.
“We have focused on individuals with complete paralysis throughout this whole process because we knew that was going to be the toughest patient population to see changes in. We’ve always thought, and we have every reason to believe, that those individuals with partial injuries have even more room for improvement,” said Edgerton.
Researchers want to continue to develop both the surgical and non-surgical methods to ensure treatment options are as broad as possible to cater to different patients’ needs.
Watch the video below to see how the men's leg movements improved after treatment.
3