Neuro-stimulation of the spinal cord allows people paralyzed after spinal injuries to walk

“This is an amazing feeling. Once again, I can bend my knees, raise my legs on my own, and even move my fingers, ”says one of the participants in the experimental treatment, who managed to regain his motor abilities due to spinal stimulation technology. After a spinal injury sustained in 2010, his legs were paralyzed.



In fact, several research groups at once, both in Russia and abroad, are working on various ways to treat paralysis caused by stroke or spinal cord injury. Thanks to innovative treatment protocols, patients with chronic paraplegia are learning to walk again.

Such technologies can stimulate the spinal cord with ultra-precise electrical impulses, activate neuromuscular connections below the trauma and at the same time strengthen the residual commands from the brain.

What rehabilitation mechanisms already exist and can be used for treatment?

A spinal cord injury leads to serious impaired motor activity, significantly reduces the quality of life and entails significant costs for families and society. To overcome the consequences of such ailments, scientists are trying to restore the ability to walk in paralyzed people.

According to neurophysiologists, a temporary coincidence between external electrical stimulation and the residual brain team is crucial for the rehabilitation of motor functions. So, in order to achieve perfect synchronization, Swiss scientists from the Lausanne Federal Polytechnic School (EPFL) linked the decoding of the motor intent of the brain with the supply of electrical signals to stimulate the spinal cord through the implant.


In Russia, the team of Yuri Gerasimenko, who for many years heads the Institute of Physiology named after I.P. Pavlova in St. Petersburg. Together with Russian and American colleagues, he managed to break the main stereotype of paralysis of the lower extremities.

Twenty years ago it was believed that spinal injuries were anatomical in nature, and the brain was directly controlling the movements of the legs. Scientists regarded the spine solely as a conductor between the brain and lower extremities, and if this connection was broken due to trauma, the person was forced to permanently transfer to a wheelchair.

But this was a fallacy.

After many years of hard work, the Institute of Physiology managed to prove that scientists of past years underestimated the importance of the spinal cord, and the spinal cord is responsible for the movements of the lower extremities of the person, in particular, the ability to walk.

The spinal cord is an organ of the central nervous system, a neural tube located in the spinal canal. It is divided into 31 segments, each of which controls its part of the body and collects information - pain, skin and muscle.



The spinal cord has all the mechanisms for initiating and regulating movements. And this means that you can "fix" a person with paralysis by acting on this particular organ. The task of scientists working at the Institute of Physiology was to learn how to control steps by stimulating the spinal cord. Neurophysiologists tested various sections of the spinal cord in animals in the longitudinal and horizontal directions, until, finally, they found a zone, the stimulation of which caused walking movements.

“In humans, like any mammal in the spinal cord, there are areas responsible for walking. Houston has set the task of applying stimulation to patients with spinal cord injury in order to initiate walking movements. And we described in all patients the zone, the stimulation of which causes the necessary reaction, ”says Yuri Gerasimenko.

In the course of further work, scientists were able to prove that spinal cord injury resulting from spinal cord injury is not anatomical, but functional. Therefore, by acting on certain centers, it is possible to restore the function impaired by trauma.

The team of Yuri Gerasimenko has developed such a technique for acting on the spinal cord, during which electrodes are placed on the nerve tube membrane, and a stimulator is implanted under the peritoneum. Due to electrical stimulation, nerve cells interacting with a conductive implant create connected chains around a damaged area and the body “repairs” the communication system between the brain and spinal cord.

Based on the results of such treatment, the patient recovers from complete paralysis to the ability to walk with his own feet. The stimulator emits electrical impulses that trigger paralyzed legs and at the same time the signals “echo” into the brain. And little by little, step by step, a person learns to control the body again.

“I even began to sit much better because my spine had grown stronger. I shoot from a bow, walk on a treadmill. Yes, I still need a walker, and the coach is watching me, but I'm sure that I will not need help soon. This is the main thing for me, ”said one of the patients, Dr. Gerasimenko.



At the same time, European scientists have been able to advance far in the issue of effectiveness and speed of treatment. If before, patients showed progress only after several months of intensive rehabilitation, most often - after about a year. That study in Switzerland showed how patients were able to walk again (with little help) after only a few days. And after several months of training, control previously paralyzed leg muscles even in the absence of electrical stimulation.

The difference in approaches was how constant the external current source was. For epidural electrical stimulation, as in other studies, a device was implanted into the patient that delivers electrical signals to the spinal column below the lesion area. When an injury disrupts the connection between the spinal cord and the brain, preventing the nerve signals from reaching the limbs, the pacemaker acts as a “bridge”, transferring electrical signals to the spine under the site of the injury.

To understand how the nervous system provides electrical signals to ensure every movement of the limbs, the researchers created a “map” of what typical brain impulses look like to activate movements. Then they determined in which region of the spine the electrodes should deliver stimulating signals to match the detected patterns and built a system that transmitted signals exactly where needed.

Scientists had to select individual system parameters for each patient. They even created personalized models of the spines in a saline solution that conducts electric current, which allowed the team to determine exactly where to place the electrodes during the next operation. Then, the electrical signal patterns were calibrated for each patient.

“All experimental subjects were able to walk using assistive devices a week later,” confirmed one of the leaders of the group of scientists Jocelyn Blotch. In subsequent tests, patients were able to arbitrarily choose the length and speed of their steps and walk the treadmill for an hour, covering a distance of about one kilometer. All movements were independently selected by a person, and the epidural implant did not generate any involuntary movements.

“Our patients had to constantly think about making appropriate leg movements. Their brain remained active all the time to process the feedback signals from the electrical stimulation that activated the muscles, ”said Karen Minassian, one of the authors of the work. Due to constant involvement, treatment has led to the fact that voluntary movements have recovered over time as the connections in the nervous system reappeared.

The success of treatment depends on a number of factors, including the severity of the injury and the level of remaining motor functions. For some, it can lead to large-scale improvements in a short time. According to scientists, testing the methodology on a larger number of experimental subjects will be an important next step. Scientists plan to study the results of the method on people who have recently received their injuries when "the plasticity potential is at the maximum level, and the neuromuscular system has not yet experienced the effect of atrophy due to chronic paralysis."

Scientists note that this technique is not yet ready for use in a clinical setting. It is necessary to carefully check all aspects of such treatment, including its effect on the daily life of the patient outside the hospital. Researchers have developed a voice-activated system that allows the patient to turn on and off epidural electrical stimulation at will, as well as choose one of several stimulation modes: walking, tricycle riding, etc. Making the implant work is an important task, but it is also necessary to make it accessible for use by the patient in everyday conditions.


Already, Russian scientists have created the next generation of such a device - a wireless stimulator. These discoveries and developments will form the basis of new international projects that will build the future of medical rehabilitation. A future in which people will not need wheelchairs.