1st patient with new 'mind-reading' device uses brain signals to write

illustration shows a man with a brain implant sitting in a chair; a cross section of the man's head shows that the implant lays on top of his brain and has a plug sticking out of the top of his head. The plug is attached to a wire that leads to a device behind the main and plugs into a monitor, on which are the words "How are you today?" — An implanted device translates brain activity into written sentences.

(Image credit: UCSF)

A man who developed paralysis and lost his ability to speak following a stroke can now communicate using a system that translates his brain's electrical signals into individual letters, allowing him to craft whole words and sentences in real time.

To use the device, which receives signals from electrodes implanted in his brain, the man silently attempts to say code words that stand in for the 26 letters of the alphabet, according to a new report, published Tuesday (Nov. 8) in the journal Nature Communications. These code words come from the NATO phonetic alphabet, in which "alpha" stands for the letter A, "bravo" for B and so on.

"The NATO phonetic alphabet was developed for communication over noisy channels," Sean Metzger, the study's first author and a doctoral candidate in the University of California, Berkeley and University of California, San Francisco's Graduate Program in Bioengineering, told Live Science. "That's kind of the situation we're in, where we're in this noisy environment of neural recordings." The researchers initially tried using individual letters instead of code words, but their system struggled to distinguish phonetically similar letters, such as B, D, P and G.

"That was great, but limited," in terms of vocabulary and in that the user attempted to speak the words aloud, Metzger said. The latest trial of the system shows that the system still worked in silence and that, by using a spelling approach, a user can greatly expand the available vocabulary. In the future, the two approaches could be easily combined: Users could rely on the whole-word decoder to quickly generate common words, and they could use the single-letter decoder to spell out less-common words, Metzger explained.

At age 20, the participant had a severe stroke that cut off blood flow to a part of the brain stem called the pons. This structure acts as a bridge between the brain and the spinal cord, and following his stroke, the participant lost much of his ability to move his head, neck and limbs and all of his ability to produce intelligible speech. In general, the man now communicates by using his limited head mobility to select letters on a screen using a physical pointer or a head-controlled cursor.

The man entered the BRAVO trial at age 36, at which time he underwent surgery to have a web of 128 electrodes laid over the surface of his brain. Crucially, these electrodes sit on top of a region of the wrinkled cerebral cortex that controls the muscles of the vocal tract, instructing them to move and thus produce specific sounds. It also covers the area of the brain involved in moving the hands.

To calibrate the decoder, the researchers cued the participant to silently attempt to say each of the NATO code words and also practice attempting to squeeze his right hand. In time, they also had him spell out arbitrary words and copy down whole sentences, letter for letter. Eventually, after spending about 11 hours training with the system, the man could spell out his own original sentences and produce answers to specific questions.

Although the new study includes only one participant, it's "still a break-through study," said Jun Wang, an associate professor in the departments of Speech, Language, and Hearing Sciences and Neurology at the University of Texas at Austin. More research is needed to know whether the same approach will work for other patients, or if it will need to be somewhat adapted for each person, Wang told Live Science in an email.

Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She is a recipient of the 2026 AHCJ International Health Study Fellowship, with a project focused on antibiotic stewardship practices in Japan and the U.S. They hold a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Beyond Live Science, Lanese's work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains involved in dance and performs in local choreographers' work.