[ad_1]
Once again, the Swiss scientists Grégoire Courtine, researcher, and Jocelyne Bloch, neurosurgeon, have achieved prowess. In their new STIMO study (STImulation Movement Overground), 3 paraplegic patients found the use of their legs through an electrical stimulation device implanted in their spinal cord. Even more remarkable, the engine benefit persisted even when the system was inactive! Results published Wednesday, October 31, 2018 in the journals Nature and Nature Neuroscience.
Restore communication between brain and muscle with electrodes
"My left leg was completely paralyzed, " says Davis Mzee, one of the patients who benefited from this new device, "Now I can extend the knee of my left leg without electrical stimulation, flex my hip and even move my toesLike the other two patients, David Mzee had a spinal cord injury, which sends messages from the brain to the rest of the body, and when it is damaged, this chain can break. In principle, signals from the motor cortex – the area of the brain that manages walking – travel along the spinal cord, reaching the neural networks in the lumbar region, which activate the leg muscles to produce the gait movements, but in patients with paralysis of one or both legs, signal transmission stops at the level of the injured marrow.
Some teams have turned to exoskeletons capable of capturing the will to walk from the patient's brain, to translate it into a real walk of the robotic body. "Involving pbadive leg movements, for example with leg exoskeletons, is not very effective in improving walking"However, Grégoire Courtine explains, their idea is to restore communication between the brain and the muscles, rather than bypbading it.
For this, Jocelyne Bloch and her team were badisted by engineers to surgically implant a network of 16 electrodes on the lumbar region of the spinal cord, in precise contact with the different nerve endings responsible for the leg muscles. The electrode array is connected to an implantable pulse generator similar to that commonly used for deep brain stimulation in Parkinson's disease, specifically upgraded to the STIMO study. Thus, rather than continuous stimulation, the generator delivers a multitude of targeted pulses, mimicking the physiological activation of the nerve fibers. These pulses respond to sensors placed at the level of the feet, able to detect the desired specific movement.
A method that allows you to rebuild nerve connections
For patients, the challenge is to coordinate their movement intentions with targeted electrical stimulation. The idea is that at the precise moment when the patient thinks of activating the muscles of his legs, the implant actually activates them. A complex and precise mechanics, which patients have quickly mastered. "The three participants in the study were able to walk, helped by a weight-bearing harness, after only one week of calibration ", tells Grégoire Courtille. It is this coincidence between thought and electrical impulses that triggers the growth of new connections in the spinal cord. A phenomenon that researchers had already observed in rats. "The doctors told me that I would never be able to walk again", testifies Gert-Jan Oskam, another patient of the study,"now, I can travel short distances with the help of electrical stimulation and crutches, and even without electrical stimulation. The strength of my muscles has improved substantially ".
This is the great strength of this work: unlike the two similar experiments carried out in the United States and published in September 2018 in Nature and the New England Journal of Medicine, the Swiss team has managed to generate intrinsic benefits for patients, even without any stimulation. "Voluntary muscle control has improved tremendously in five months of training", confirms Gregoire Courtine.The human nervous system has responded even more deeply to treatment than we thoughtDuring the rehabilitation sessions, the three participants were able to walk hands-free for over a kilometer thanks to targeted electrical stimulation and an intelligent system of weight support (a robot that supports the patient to the extent of its progress.) These longer and more intense workouts have all the more activated the plasticity of the nervous system, resulting in improved motor skills even when electrical stimulation is turned off.Today, the three paraplegics can walk with crutches or a walker and the help of electrical stimulation, thanks to a dedicated application controlled by a watch, which responds only to their voice, and allows them to adapt the electrical stimulation to their training needs.
The earlier the better
Grégoire Courtine and Jocelyne Bloch have already co-founded the startup GTXmedical, which will use these discoveries to develop customized neurotechnology, available to hospitals and clinics around the world. "We are building the next generation of neurotechnology, which will be tested soon after the trauma, when the recovery potential is high and the neuromuscular system has not yet experienced the phenomenon of chronic paralysis atrophy. "says Grégoire Courtine.
Source link
