Five men with complete motor paralysis have regained the ability to move their legs voluntarily and produce step-like movements after being treated with a non-invasive form of spinal cord stimulation. The new treatment builds on prior work to generate voluntary movements in paralyzed people through electrical stimulation – in particular, two studies (one completed in 2011, the other in 2014) that involved surgically implanting an electrode array on the spinal cord. This time, however, the researchers found success without performing any invasive surgery.
The new treatment uses a technique called transcutaneous electrical nerve stimulation, which involves strategically placing electrodes on the skin of the lower back. While receiving stimulation, the men’s legs were supported by braces that hung from the ceiling. At first their legs only moved involuntarily, if at all. But they soon found they could voluntarily extend the distance their legs moved during stimulation. They doubled their range of voluntary motion after four treatment sessions.
In an effort to further improve voluntary motion, the researchers gave the men a drug called buspirone during the final four weeks of the 18-week study. This drug mimics the neurotransmitter serotonin, and it is known to induce walking motions in mice with spinal cord injuries.
All five men had been paralyzed for more than two years prior to receiving the treatment, which lasted 45 minutes at a time and was conducted once a week for the duration of the study. But by the end of the study, after they had received the buspirone drug, they could all move their legs with no stimulation at all. This movement was comparable to what they achieved while receiving stimulation.