Scientists at the Swiss Federal Institute for Technology have come up with a way of reactivating severed spinal cords in paralyzed rats using epidural electrical stimulation (EES), allowing them the ability to walk again via remote control. Human trials for their system should begin shortly as well.
“We have complete control of the rat’s hind legs,” EPFL neuroscientist Grégoire Courtine said in a statement. “The rat has no voluntary control of its limbs, but the severed spinal cord can be reactivated and stimulated to perform natural walking. We can control in real-time how the rat moves forward and how high it lifts its legs.”
The first step was to tune the EES pulses accurately enough to control the fine motor functions of a normal gait. To do this, the researchers put paralyzed rats onto a treadmill and supported them with a robotic harness. After several weeks of testing, the researchers had mapped out how to stimulate the rats’ nervous systems precisely enough to get them to put one paw in front of the other.
Next, the team developed a robust algorithm that could monitor a host of factors like muscle action and ground reaction force in real-time. By feeding this information into the algorithm, EES impulses could be precisely controlled, extremely quickly.
The result, the researchers say, is a closed-loop system that can make paralyzed subjects mobile.
Courtine is quick to note in the above EPFL video that while his team hasn’t found the cure for spinal cord injury-related paralysis, they’ve developed a system that can, and will be scaled to human size.
According to the researchers, human trials are scheduled to begin during summer 2015. The trials will take place at the EPFL, in a specially-designed Gait system, which includes a treadmill, harness support for the subjects, and myriad cameras and sensors to measure their performance.