The brain-computer interface works without assistants

The implant for the first time helped a completely paralyzed woman to communicate

marks, Geektimes

In medicine, unfortunately, there are very severe cases of paralysis, when a person is conscious, but can neither move nor speak. Patients of this kind completely lack the ability to communicate, they can only think. Moreover, the mind of such people is clear in most cases, people are aware of their situation and the situation. Now scientists have developed an implant for the human brain that allows paralyzed patients to communicate via a computer. A person's thoughts are transformed into words and whole sentences. In this case, patients do not need the mediation of a doctor.

"This is the world's first implantable system that works without the need for assistance from doctors," says neuroscientist and project leader Nick Ramsay from the University of Utrecht Medical School (in a press release UMC Utrecht Paralyzed ALS patient operates speech computer with her mind). The implant was recently tested in a clinical setting. The first person to receive such a system was Hanneke de Bruijne. In 2008, she was diagnosed with amyotrophic lateral sclerosis (ALS), and now she is completely paralyzed.

ALS is a slowly progressive, incurable degenerative disease of the central nervous system, in which both the upper (motor cortex of the brain) and lower (anterior horns of the spinal cord and cranial nerve nuclei) motor neurons are affected, which leads to paralysis and subsequent muscle atrophy. It is characterized by progressive damage to motor neurons, accompanied by paralysis (paresis) of the limbs and muscle atrophy.

The patient still has the opportunity to control the muscles of the eyeballs, that is, to make eye movements. During the meeting with the author of the project, she retained this ability and breathed independently, without an artificial lung system. Two years later, she lost her ability to breathe, so the artificial respiration apparatus keeps her alive. Nevertheless, the eye muscles are still working, although this is only temporary. Not so long ago, a communication system was installed for the patient, which works by tracking the movements of her eyes.

Nick Ramsey decided to develop a system whose functioning does not depend on the movement of patients' eyes or any other motor activity. For example, Stephen Hawking, also affected by amyotrophic lateral sclerosis, works with a device that tracks the movements of the muscles of his cheek.

Such a system, according to the expert, can only be a device that is able to track the electrical activity of the brain. The project manager talks about such a device as a system that reads thoughts. In general, you can say that. Various implants that read the activity of brain cells have been around for a long time. For example, such systems are used to create bionic prostheses that replace people with their own limbs.

But here we are talking about a device that should help the patient not to make movements with a prosthesis, but to demonstrate his thoughts. Moreover, Ramsey and his colleagues immediately decided to create a system that could work not only in a clinical setting, but also at home, without anyone's help. The main working element of such a system is an implant that is surgically implanted into the human brain. This part of the computer system has two electrodes. They are implanted in the area of the cerebral cortex that controls human movements. The precise installation of the electrodes is critically important. One of them is located in the part of the cerebral cortex that is responsible for the movements of the right hand. And the second one goes to the area that activates only when a person starts counting down.

These electrodes are connected to a transmitter implanted in the patient's shoulder. It transmits data to a computer located in front of the patient, who has the ability to monitor everything that happens on the screen.

When the patient looks at the display, she sees a virtual square moving through the letters. As soon as the square passes over the letter that she needs, the woman mentally represents the movement of her right hand pressing on this letter. Her brain is quite capable of generating a signal, which in a normal situation is fed into the muscles of the arm. This electrical signal is picked up by the transmitter and sent to the computer. The letter marked by the patient is highlighted. Words are formed from letters, sentences are formed from words. The system makes almost no mistakes, its accuracy is about 95%.

"Using such a system is a slow process. Writing a word can take several minutes. But the patient trains, and the work goes faster," said one of the study participants. He also added that previously a woman had to choose a letter for about 50 seconds. Now it takes her only 20 seconds.

This system, according to its developers, is much more reliable than the previous one, which read eye movements. The fact is that in bright sunlight, the sensor does not work, and the paralyzed woman loses the opportunity to communicate. But the new system works in any light.

"Now I can communicate outside the house when my eye movement tracking system is not working. I feel more independent and confident when I'm on the street," says Bruijne.

Of course, the system needs to go through many more tests before it is approved and developers can provide it to other people. In addition, the authors of the project are going to add a number of electrodes and improve signal processing by the system. This, according to them, will speed up the communication process.

The scientists presented the results of their work in the New England Journal of Medicine (Vansteensel et al., Fully Implanted Brain–Computer Interface in a Locked-In Patient with ALS).

Portal "Eternal youth" http://vechnayamolodost.ru  15.11.2016