Your body is controlled by nerves that connect, via your spinal cord, to your brain. When someone becomes paralyzed through trauma, it's often because these nerves are damaged. . Without signals running through them, messages from the brain don't make it through to muscles. In the past, scientists have used artificial circuits to help a monkey regain function in its paralyzed paw, and researchers have now helped four men with below-waist paralysis regain some movement in their legs. Each of the four had been paralyzed for more than two years.
The researchers got this to work in much the same way as with the monkey. By implanting electrodes along the men’s spinal cords, they were able to reawaken nerves via electric stimulation. Afterwards, the men could flex their main joints (including toes, ankles, knees). This ability has only grown by combining physical therapy with electrode implants.
Dr. Roderic Pettigrew, director of the National Institute of Biomedical Imaging and Bioengineering at the U.S. National Institutes of Health, called this a “substantial milestone,” as the men gained the ability to mimic a computer-generated wave by moving their legs up and down. Three of them have gained the ability to change the force they use while flexing their legs. One of the men can even stand for short periods of time. The electric current, which flows through 16 electrodes implanted into the spinal cord, must be flowing for the men to move. Researchers hope that combining it with therapy will help the men rebuild those pathways.
One of the most interesting things to come out of the research is the fact that it turns out the nerve pathways to the legs don’t need to be completely intact. Says study co-author Reggie Edgerton, "there must be some information getting from the brain past the spinal cord injury to the lower spinal cord that controls the movement of the legs, but the amount of information that's getting across is so small it's not enabling the patient to move. The stimulation increases the excitability of the spinal circuits, enabling the person to perform some of these movements."
The next step is to do further testing on more people. While the results have been amazing, four people isn’t enough to come to a consensus on the technology. Still, there’s nothing to indicate that this won’t work on others, and it could mean a second chance for those who have suffered paralysis.