Talking with relatives, playing a computer game and controlling a prosthesis - all this can be done even
How do paralyzed people return to normal life?
James Johnson hopes he can sit down one daybehind the wheel again. If he does this, then only using the power of his thoughts. In March 2017, Johnson broke his neck in an accident and was left almost completely paralyzed from the shoulders down.
Johnson's rehabilitation specialists introduced him toby researchers at the California Institute of Technology (Caltech) in Pasadena. He was invited to join a clinical trial of a brain-computer interface (BCI or BCI).
First he underwent neurosurgical surgery andimplanted two grids of electrodes into the cerebral cortex. These electrodes record the firing of neurons in the brain. Next, researchers use algorithms to decipher his thoughts and intentions. The system then uses Johnson's brain activity to operate computer applications, or to help him move in a specific direction.
The first time Johnson used the brain-computer interface, implanted in November 2018, he was able to move a cursor around the screen. To do this, you just had to think about it.
Since then, Johnson has used the BCI to controla robotic arm to play video games and drive a simulated car in virtual reality. Johnson is one of 35 people who have had a BCI implanted in their brain long-term. Only about 12 laboratories conduct such studies, but this number is growing.
How well do devices read thoughts and help you do what you want?
Over the past five years, the range of skills thatcan be restored using the BCI has expanded significantly. Just in 2021, scientists described a case in which a patient used a robotic arm that sent sensory feedback directly to his brain. Also a prosthetic speech device for those who have lost the ability to speak due to stroke. And a man who could communicate at record speed while imagining he was writing by hand.
Can speech be restored?
“One of the most serious consequences of brain injury is the loss of the ability to communicate,” says Edward Chang, a neurosurgeon and neuroscientist at the University of California, San Francisco.
At the beginning of work with the BCI, participants could movecursor on the computer screen, imagining the movement of their hand and how they press the keys. This cursor-based communication was capable of transmitting approximately 40 characters per minute, a record set in 2017 by a team led by Krishna Shena, a neuroscientist at Stanford University in California.
Then, in 2021, the same group reported a new approach in which a member, Dennis Degrare, was able to convey twice as many characters.
Shenoy's colleague - Frank Willett - suggested to Degrayimagine him writing the words by hand while researchers study data from his motor cortex. The system sometimes had a hard time parsing signals that concerned letters visually similar to the letter - r, n and h, but in general it could easily identify all letters.
The decoding algorithm showed an accuracy of 95%, but when using auto-correction, similar to the one in a regular smartphone, the accuracy increased to 99%.
But there is another way to convey information.Edward Chang, a neurosurgeon and neuroscientist at the University of California, San Francisco, came up with an approach that focuses on speaking rather than writing. Just as text is made up of individual letters, speech is made up of individual units called phonemes. In English, there are about 50 phonemes: each can be obtained with a certain movement of the vocal tract, tongue and lips.
Chang's group first worked to study partThe brain that generates phonemes and therefore speech is a poorly understood region called the dorsal laryngeal cortex. Researchers have created a speech decoding system that displays the user's decoded signals as text on the screen. In 2021, the group reported that the device allowed a person to communicate using a predetermined set of 50 words. The speed was 15 words per minute.
In this case, the scientists did not record data fromindividual neurons. Instead, they used electrodes placed on the surface of the cerebral cortex, which detect the average activity of all neurons. The signals are not as accurate as those from electrodes implanted in the cerebral cortex, but the approach is less invasive.
Are there such devices in the public domain?
Today, most implantswhich record the activity of individual neurons, was created by Blackrock Neurotech. They are medical device developers based in Salt Lake City. But over the past seven years, commercial interest in BCIs has increased dramatically. For example, in 2016, entrepreneur Elon Musk launched NeuraLynx in San Francisco to develop a similar device. The company raised $363 million.
Chairman of the Board of Blackrock NeurotechFlorian Solzbacher said he wants to bring the BCI system to market within a year. In November 2021, the US Food and Drug Administration (FDA), which regulates medical devices, launched an expedited review process for the company's products to make it easier to bring them to market. Perhaps their interface will become the first mass product in this area.
What's next?
Experts emphasize that developerscommercial BCI devices will have to operate without any expert supervision for months or even years. It is also important to make sure that the interface functions equally well for each user.
They also noted that advances in machine learning will help solve the first problem. But to achieve universal efficiency regardless of the user is a more difficult task.
In addition, ethicists emphasize thatthat users should retain full control over device data. Modern technologies cannot decipher people's private thoughts, however, developers will have data on all the user's dialogues, as well as important data on the health of their brain. It is noted that IMC is a new type of cybersecurity risk.
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