moussoua

A paralyzed man who is unable to speak or print letters has succeeded in expressing more than a thousand words thanks to a neuro-compensation device that translates his brain waves into actual phrases, according to US researchers.

The patient's favorite sentence was "Nothing is impossible," said Sean Metzger of the University of California at San Francisco, the first author of the study, whose results were published Tuesday in the journal Nature Communications.

The team of this American university proved last year that an interface linking the brain and the computer can express in the spoken language fifty common words that the man was trying to pronounce, according to a report by Agence France-Presse.

As for the new study, it has proven that the interface is able to decipher the 26 letters of the global verbal alphabet that men use to silently pronounce words.

grammatical linguistics

Metzger explained to the French press agency this mechanism, explaining that to say a word like "cat", he used to pronounce "Charlie - Alpha - Tango", words whose first letters indicate the letters of the desired word.

The interface then uses a system that models language in real time to identify words or errors detected in the sequence of spoken characters.

Thus, the researchers were able to decode more than 1,150 words, which represents more than 85% of the content of typical sentences in the English language.

The simulation showed that this vocabulary set could expand to more than 9,000 words, which is the number of words most people use over the course of a year, Metzger said.

The interface was able to decode about 29 characters per minute, with an error rate of 6%, or nearly 7 words per minute.

Metzger thinks that this speed could be even higher in the future, combining the interface's abilities to understand 50 common words with an understanding of the alphabet of less frequently used words.

The participant in the trial was named BRAVO1, based on the name of the Brain-Computer Interface Restoration of Arm and Voice trial.

This patient, in his thirties, was attacked at the age of twenty, which caused him to have a speech disorder called anarthrosis, which makes the patient's speech incomprehensible, while his cognitive functions remain normal.

Few patients

This patient usually communicates with others using a stylus attached to a baseball cap, allowing him to point his head at the letters on the screen.

The researchers implanted a high-intensity electrode in his brain in 2019, above the motor cortex responsible for speech, and they have since monitored the electrical impulses generated there when the patient tries to speak.

Patient Bravo1 "really enjoyed the experience, as it enabled him to communicate with us quickly and easily," Metzger said.

"I learned a lot about it," he added, by asking the patient to say what they're thinking. For example, "He didn't like the food at all where he lived."

A study by researchers from Stanford University last year showed that the brain-computer interface can decode 18 words per minute, when a participant imagines writing sentences.

But according to Metzger, the best solution is to use an interface that combines letter detection, phonetic and verbal alphabets.

The results are so amazing

The trial, whose results must be confirmed with other participants, is still too far from the reach of the thousands of patients who lose their ability to speak due to stroke, accident or disease every year.

Patrick DeGeneres, professor of neuroscience at Newcastle University in Britain, praised the "very impressive results".

Because this type of surgery "is highly invasive and has high risks", DeGignard noted that such a device would only be viable for a very small number of patients in the near future.