David Mzee, 28, was injured in a gymnastics accident in 2010. The doctors told him he would most probably never walk again. Gert-Jan Oskam, 35, was riding his bicycle home from work when he was hit by a vehicle in 2011. He became a paraplegic.
Mzee and Oskam were two of three participants in a study using epidural electrical stimulation, a spinal cord stimulation technology aimed at helping paralyzed individuals regain the use of their leg muscles. The results were astounding! Two of the participants were able to take a few steps on their own – even after the stimulations were turned off. The third, who had been unable to use his legs at all, was able to move them lying down.
In previous studies with rats, cats, and monkeys, epidural electrical stimulation enabled “standing, walking in various directions, and even running.” Human have reacted differently; researchers surmise a variety of physiological reasons, such as size, may be the reason why.
How does epidural electrical stimulation work? Injuries in the spinal cord interrupt the connections between the brain and spinal cord neurons, thus creating partial or complete paralysis. A portion of the nerves usually remains intact in spinal cord injuries, but the connection isn’t strong enough to enable movement.
Gregoire Courtine, a neuroscientist at the Swiss Institute of Technology, worked together with his team in Lausanne to map out exactly which areas of the spinal cord are involved in the specific movements necessary for walking. They then implanted electrical stimulators to give participants a sequence of electrical pulses to stimulate the spinal cord.
Unlike those of previous studies, Courtine’s stimulations only targeted the precise location of the movement. The stimulation also only occurred when participants tried to move themselves. In other words, the stimulations worked in conjunction with the participant.
The results were dramatic. Within a week, participants were able to walk with body weight support devices. After five months of rehabilitation, they were able to take a few steps even when the extra stimulation was turned off!
One of the basic principles of neuroscience is “cells that fire together will wire together.” Courtine and neurosurgeon Jocelyn Bloch founded GTX Medical based on that principle. The start-up is using neurotechnology to make electrical stimulations available to participants outside the lab. Participants will receive wearable sensors that elicit stimulation, as well as an app that runs on a voice-controlled watch, thereby enabling patients to choose the precise form of stimulation.
The devices are in development. Courtine’s team hopes to have them tested and ready for use within the next three years.
Although ground-breaking, this kind of neurotechnology is still in its early stages. Even today, the three participants in the study are using wheelchairs for much of their daily life. Further research is needed to determine precisely which types of paralysis patients this form of neurotechnology can help.
One thing is certain, though: Wheelchair-bound individuals have reason to be hopeful!