Thanks to a recent breakthrough by UCLA researchers, the nearly 1.3 million Americans living with paralysis due to spinal cord injuries may have new hope for recovery.
A study published in Journal of Neurotrauma examined subjects who'd been totally paralyzed for at least two years. After receiving an experimental treatment, five of them were able to move their legs in a rhythmic stepping motion. The therapy combined electrical stimulation with doses of a drug called buspirone, which normally is used to treat anxiety disorders.
UCLA scientist V. Reggie Edgerton, one of the study's coauthors, says the research built upon a 2014 experiment that enabled four patients to move their legs by surgically implanting electrical stimulation devices next to their spines. This time, however, the researchers got results without surgery by using transcutaneous stimulation, in which electrodes were attached to the skin over various sections of their spines.
Just as importantly, says Edgerton, the two studies provide evidence that neural connections in the vicinity of a spinal cord injury don't necessarily die, and that it's possible to switch them on again.
"What we think this means is that the cells were damaged in the lesion area, but that they weren't dead," Edgerton explains. "Somehow, the stimulation awakened what were dormant networks."
And not only did the new technique work for all of the experimental subjects, but once reactivated, those connections stayed on, even when the electrodes were no longer supplying juice.
According to the National Institutes of Health website, the five patients in the new study – all male – received 18 weekly treatment sessions in which their spines were electrically stimulated for 45 minutes at a time. In addition, physical therapists manually moved their legs in a step-like pattern to condition the long-unused muscles in their legs. During the final four weeks, the patients also received twice-daily doses of buspirone, which in previous research has helped mice with spinal cord injuries to move.
At various points during the study, the patients' legs were put into braces attached to the ceiling, which enabled movement without resistance from gravity. The researchers then asked them either to try to move their legs, or else to resist electrical stimulation that activated their muscles involuntarily.
At first, the patients' legs moved only when the electrical stimulation induced involuntary movement. But after a month, they were able to move their legs by themselves. After the drug was added to the treatment, by the end of the study they were able to move their legs just as much with no electrical stimulation at all.
A nonsurgical treatment for paralysis would provide significant advantages over implants, because it would be vastly cheaper and safer, and might be made available more easily to many patients.
The new technique is still in the early stages of development, and it may take years of work to develop a treatment that could be used widely to help paralysis patients. UCLA researcher Yury Gerasimenko, a co-author of the study, says that the next step will be combining electrical stimulation with robotic exoskeleton technology, so that patients can begin to support their own body weight as they move. According to an email from Garasimenko, that synergy "has huge potential for enhancing motor function recovery."
While restoring paralyzed patients' ability to walk is the ultimate goal, Edgerton says that even just enabling them to stand on their own for short periods would enable various physiological systems in their bodies to work better, and would make a potentially huge difference in their health.