Igor Lavrov, Dmitry Saenko, Yuri Gerasimenko and other scientists at the neuroscience laboratory at the Mayo Clinic (USA) applied electrical stimulation of the spinal cord to help Paralyzed patient named Jered Chinnock to move his legs, stand almost unaided (at a voltage of 2.1 volts) and absolutely without assistance (when the voltage was raised to 2.2 volts). According to scientists, for the first time in the history of medicine, epidural electrical stimulation (EES) allowed the paralyzed patient to perform such actions within just two weeks, that is, eight EES stimulation sessions after implant activation.
In the epidural space of Jared's spine, a bar with 16 electrodes was inserted (Specify 5-6-5, Medtronic). The electrodes received a signal from another RestoreSensor SureScan MRI (Medtronic) implant and stimulated the spinal cord without any effect on the muscles. The signals were pulsed by 0.5 milliseconds at a frequency of 1 Hz with a voltage of up to 5.5 volts.
Even without prior training, the paralyzed patient was able to move his fingers and legs with willpower. The miracle, to which all the others are accustomed, the so-called. "Normal" people.
Jared Chinnock broke his back three years ago as a result of a car accident. Damage to the spinal cord in the sixth thoracic vertebra means that the guy could not feel anything below the torso. Although the legs and other organs remained intact, but they were no longer transmitted by the brain.
Before the implantation of the device, the patient underwent multiple sessions of intensive physical therapy. A group of 30 specialists worked on it for 22 weeks, spending three workouts a week. They had to restore muscle tone and prepare them for exercise and receiving signals from the spinal cord. It was also important to stimulate the spinal cord itself: to determine those specific places where neuronal activity is observed during the stimulation of the muscles and attempts of certain movements on the part of the patient. It was to these places that 16 electrodes were then installed.
Doctors consistently performed tests – and some of the results led to the conclusion that the spinal cord injury can be "reversible," that is, you can try to restore the signal through the injury site in The lumbosacral spine.
The illustration shows the profile of spinal cord injury in the patient. It shows that some indicators improved after 16 weeks of physical therapy, compared to after 8 weeks. Only in the second month of the test, the first activity was recorded in the patient according to the results of electromyography (in illustration F on the lower right).
After physical therapy, the patient was implanted into the epidural space of the spine just below the spot Damage in the sixth thoracic vertebra – in the lumbar thickening approximately in the middle of the back. The electrode was connected to a computer-controlled device, mounted under the skin. The idea was to modulate the signal, which would naturally pass through neurons of the spinal cord. The computer transmits a signal to the device, and it modulates a signal of a certain type through the electrode.
Jared says that he was able to move his fingers on the first day when the specialists activated the electronic stimulator. Within two weeks he successfully made walking movements (lying on the couch) and independently stood in place without the help of doctors, only with self-support by the hands of the upper body for parallel bars.
Indicators of electromyography (below) when signals with different voltages are applied through these electrodes: 1.5 volts and 2.2 volts
Jared moves his foot with varying degrees of intensity
Neurosurgeons say that the results of the experiment exceeded expectations, and the patient continues to show progress as it becomes accustomed to neuromodulation from the implant.
This medical case was described on April 3, 2017 in the journal Mayo Clinic Proceedings .
] The paralyzed patient stands still, and is also rockingly controlled
Neuro-engineers express the hope that further development of this technology will help restore the basic motor functions to many other paralyzed people. Of course, they will not be able to run like sportsmen, but they can at least stand still without help and even walk slowly. Apparently, the condition for partial return of motor functions is that the damage is irreversible. But in order to make sure that a signal can still pass through the damaged area of the spinal cord, in any case it will take long studies, tests and therapy.
Unfortunately, scientists have not yet succeeded in deciphering the real signals that the brain sends to the spinal cord. The current experiments are similar to the experiments of Pavlov, although at a higher level. Scientists are only groping for a way to truly control the nervous system from the outside and translate signals from the computer into the neurons and back, with decoding and coding in real time.