Brainwave implant lets paralyzed man spell 1,100 words in US

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A paralyzed man who can’t speak or type could spell more than 1,000 words with a neuroprosthesis that translates his brain waves into full sentences, US researchers said Tuesday.

“Anything is possible” was one of the man’s favorite phrases to spell, said lead author of a new study on the study, Sean Metzger of the University of California San Francisco (UCSF).

Last year, the team of UCSF researchers showed that a brain implant called a brain computer interface could translate 50 common words if the man tried to pronounce them in full.

In the new study, published in the journal Nature Communications, they were able to decode it silently by mimicking the 26 letters of the phonetic alphabet.

“So if he tried to say ‘cat,’ he would say charlie alpha tango,” Metzger told AFP.

A spelling interface then used language modeling to process the data in real time and work out possible words or errors.

The researchers were able to decode more than 1,150 words, which “represent more than 85 percent of the content in natural English sentences,” the study said.

They simulated that this vocabulary could be expanded to more than 9,000 words, “which is basically the number of words most people use in a year,” Metzger said.

The device decoded about 29 characters per minute, with an error rate of six percent. That equated to about seven words per minute.

The man is called BRAVO1, as the first participant in the Brain-Computer Interface Restoration of Arm and Voice trial.

Now in his late thirties, he suffered a stroke when he was 20, which left him with anarthria — the inability to speak intelligibly, although his cognitive function remained intact.

Normally, he communicates by poking at letters on a screen with a pointer on a baseball cap.

In 2019, the researchers surgically implanted a high-density electrode on the surface of his brain, over the speech motor cortex.

Through a gate embedded in his skull, they have since been able to track the different electrical patterns produced when he tries to say different words or letters.

‘Unique advantage’

Metzger said BRAVO1 “really enjoyed using this device because it can communicate with us quickly and easily”.

One of the best parts of the study was when BRAVO1 was told to spell “whatever it wants,” Metzger said.

“I learned a lot about him,” Metzger said.

One of BRAVO1’s surprising comments was that “he really didn’t like the food where he lives,” Metzger added.

Last year, a brain-computer interface developed at Stanford University could decode 18 words per minute when a participant imagined handwriting.

But Metzger said their speech-based approach has a “unique advantage.”

The 50 commonly used words — which the participant pronounces in full in silence — can be used for many interactions, while rarer words can be spelled out, offering the “best of both worlds,” he said.

The study, which has yet to be confirmed with other participants, is a long way from becoming available to the thousands of people who are unable to speak each year due to stroke, accident or illness.

Patrick Degenaar, a professor of neuroprosthetics at Newcastle University who was not involved in the study, praised the “very impressive results”.

Because neuroprosthetic surgery “is highly invasive and carries risks,” such a device would likely only be used by a very small number of people for the foreseeable future, he told AFP.

(This story was not edited by DailyExpertNews staff and was generated automatically from a syndicated feed.)