Liat Clark reports that four paralyzed people have “voluntarily and independently moved their legs” for the first time since their injuries, thanks to an experimental spinal implant:
Each of the four men received an epidural implant that delivers currents that mimic signals from the brain. They work in a similar way to myoelectric prostheses, which are grafted on to remaining nerves in the muscles and stimulate these to control movement. In these cases, those wearing the prosthetic can actually move the artificial limb voluntarily, just by thinking about it, because those salvaged nerves are still receiving information from the brain. In this latest study, the candidates could voluntarily move their limbs immediately. This has led to knock-on improvements in their health, from an increase in muscle mass to a reduction in fatigue and stabilizing of blood pressure levels. …
Each recovered and managed to make use of the system so rapidly, it’s speculated that more parts of the nervous system remained intact than previously thought. Not only this, but as the four candidates continued through their training, they needed lower and lower electrical frequencies to instigate movement – the neural pathways were improving and building off of that stimulus to create better routes. They are retraining the spinal cord to think differently.
Sam Maddox offers an account of how it played out for one man:
Kent had the stimulator implanted. A few days later they turned it on. No one expected it to do anything. Researchers were only looking for a baseline measurement to compare Kent’s function later, after several weeks of intense Locomotor Training (guided weight supported stepping on a treadmill). Kent tells the story: “The first time they turned the stim on I felt a charge in my back. I was told to try pull my left leg back, something I had tried without success many times before. So I called it out loud, ‘left leg up.’ This time it worked! My leg pulled back toward me. I was in shock; my mom was in the room and was in tears. Words can’t describe the feeling – it was an overwhelming happiness.”
The Dish 