Suddenly a man stands up and starts walking: an electric device allows paralyzed people to move their legs

Electrodes inserted along the spines of four disabled people allowed them to move their toes, ankles and knees. At the same time, the researchers claim that this is not a complete cure.

Four men paralyzed below the waist regained some movement in their legs after a series of electrodes were implanted along their spines and reactivated long-paralyzed nerves, researchers explain.

Electrical stimulation of the spinal cord gave the men the ability to voluntarily bend their toes, ankles and knees, with the strength and accuracy of the movements improving over time with physical rehabilitation, the researchers say. "The really exciting news that comes out of this study is that spinal cord injury may no longer be a sentence of lifelong paralysis," said Dr. Roderic Pettigrew, director of the National Institute for Biomedical Imaging and Bioengineering at the US National Institutes of Health (NIH). ). "This is a significant achievement that is a milestone in the treatment of paralysis."

All participants in the experiment are now able to coordinate the movements of the foot, ankle and toes in full synchronization. Three of the four experimenters are able to change the strength of their leg flexion. The research findings were published in the scientific journal Brain. The first experimenter into whose body the implants were inserted, Rob Summers, is able to stand without assistance for a short period of time, thanks to physical rehabilitation that includes standing and walking on a treadmill while tying the experimenter to a harness.

"Right now I'm able to stand, and I'm even able to move my ankles, toes, knees and hips," said experimenter Summers, 28, who received the special implants four years ago. ” I can do sit-ups, which is crazy. Today I do about half an hour of sit-ups without any help from others." The researchers said that they were most surprised by the improvement seen in two subjects who had complete motor and sensory paralysis. In these patients, the pathway through which sensory information is transmitted from the legs to the brain is completely destroyed, and similarly the corresponding pathway from the brain to the legs.

The researchers believed that the sensory pathway must be at least partially healthy in order for a person to control nerves that are reactivated by electrical stimulation. "There must be certain information coming from the brain through the damaged spine to the bottom of the spine that controls the movement of the legs, but the amount of information transmitted in this pathway is so small that it does not allow the patient to move," explains one of the researchers. "The stimulation increases the arousal of the pathways in the spine and thus allows the person to redo some of these movements."

At this stage, the device that generates the electrical stimulation must be activated in order for the person to move. "One of the experimenters is able to move part of the time without powering on the device, but the movement is not good enough and not stable enough," said one of the researchers.

The research revolves around a spinal nerve stimulation unit that sends a constant current of energy into the spine using an array of 16 electrodes implanted under the bone of the spine, explains the researcher. The first experimenter received his implants in 2009. The goal, the researchers say, was to increase the sensitivity of local pathways within the spine responsible for basic motor functions that do not require receiving information from the brain. The stimulation device worked as intended, with his legs and quadriceps moving on their own. "It felt like pins and needles, like you fell asleep on your arm and then it started waking up again," the patient said. The immediate result greatly surprised the researchers. "In the first experiment he was really able to move the little toe of his foot and also the legs themselves," said the lead researcher. "We really had to rethink how humans control their movement."

Part of the sensory pathway in the patient's legs was still intact after he was silent in 2006 when he was hit by a car. "He still had a certain sensation in these areas, so we knew that there was still a connection to the brain," explains the researcher. "There were still a number of signals there."

Following the results of the first trial, they tried the implants on three more patients, including two who did not receive any sensory signals from their legs. All were able to move their legs as soon as the electrical stimulation was applied, says the lead researcher, and within days they could control some of their movements. The main point, claims the lead researcher, is that "among four out of four patients we were able to observe something that 99.9% of the scientists or doctors claimed all these years was impossible. It proved to us that there is a new potential within the spine that we still haven't exploited to date." And what's more, all the patients had been paralyzed for over two years. "We demonstrated that the flexibility of the brain and the spine is not limited to 12-6 months from the moment of the injury," explains the researcher. "She can survive for many years."

The next steps are improving the technology underlying the electrical stimulation and testing a larger number of experimenters, explains the lead researcher. The initial research of the four experimenters was funded with the help of funds that came from the US National Institutes of Health, and the researchers are now looking for a budget to insert these implants into dozens of additional experimenters. "I believe that if we can implant this electrical device into 30 to 40 additional subjects, it will really pave the way for proof of the clinical importance of this device," said the lead researcher. In addition, the current results were collected using a device originally developed to help people control their pain, the researcher says. The researchers are interested in developing a next-generation model specifically designed to create mobility in paralyzed people - perhaps one whose electrodes can be placed through the skin, so that surgery would not be necessary. The first experimenter believes that this research will eventually allow him to walk. "My ability to stand continues to be more stable and independent," said the first experimenter. "I fully believe that my mobility and functionality are waiting for me around the corner."

The original news about the study is on the NIH website