New research exposes an exciting step forward
By sending electrical signals to stimulate severed spinal cords in rat subjects, researchers from the École Polytechnique Fédérale de Lausanne (EPFL) in Vaud, Switzerland have been able to allow rats to walk again. The study was published in the journal Science Translational Medicine on Sept. 24, 2014.
The brain functions and controls the body by sending electrical signals down a specific neural pathway. When the brain cannot communicate with parts of the body, like when the spinal cord is severed for example, these electrical signals are unable to travel, resulting in events such as paralysis.
However, by using a pharmacological cocktail injected in the bottom half of a severed spinal cord, as well as a machine sending precise electrical signals, researchers at EPFL soon discovered that they were able to simulate the act of walking in rat subjects. Since the rats were unable to hold themselves up naturally, a robot was used to simulate natural walking posture.
“We have complete control of the rat’s hind legs,” said EPFL neuroscientist Gregoire Courtine. “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.”
As research continued, scientists discovered that there was a direct relationship between how high a rat lifted its legs and the frequency of the electrical signal sent to its spinal cord. Using an algorithm to carefully account for varying surface elevations – like stairs and slopes – researchers were able to send electrical signals at specific frequencies to mimic natural walking behaviour.
Co-author and fellow EPFL neuroengineer Silvestro Micera explains that being able to understand how to properly manipulate damaged spinal cords can lead to the development of better neuroprosthetic devices.
“We believe that this technology could one day significantly improve the quality of life of people confronted with neurological disorders,” explained Micera.
For humans currently suffering from debilitating spinal injury, the research comes as a possibility of returning to a life with complete bodily control. Adding to the excitement is the announcement that Courtine and Micera’s team will be conducting human studies as early as next summer.
Putting together the monitoring and rehabilitation technology used on the rat subjects, Courtine and Micera have developed a new “Gait Platform” that consists of custom-made equipment that generates information about leg and body movement.
The Gait Platform consists of treadmills, an overground support system, 14 infrared cameras that detect markers on patients’ bodies, as well as two video cameras to record additional information.
Courtine is quick to emphasize that the Gait Platform is purely for research.
“The Gait Platform is not a rehabilitation centre,” explains Courtine. “It is a research laboratory where we will be able to study and develop new therapies using very specialized technology in close collaboration with medical experts here at the [University Hospital of Lausanne], like physiotherapists and doctors.”
Regardless, this new research represents an exciting step forward.