• Posted May 29, 2024

AI Implant Allows Stroke Survivor to Communicate in Both Spanish, English

A bilingual brain implant has allowed a stroke survivor to communicate in both Spanish and English, scientists report.

Turning to an AI method known as a neural network, researchers trained the patient's implant to decode words based on the brain activity produced when he tried to articulate those words, and then display those words and sentences on a screen.

This method allows the brain implant to process data in a way that is similar to the human brain.

Scientists at the University of California, San Francisco's Center for Neural Engineering and Prostheses have labored for years to design a decoding system that could turn the patient's brain activity into sentences in both languages.

In a report published May 20 in the journal Nature Biomedical Engineering, the scientists share the details of their effort.

“This new study is an important contribution for the emerging field of speech-restoration neuroprostheses,” Sergey Stavisky, a neuroscientist at the University of California, Davis, who was not involved in the study, said in a journal news release.

Even though the study included only one patient and more research is needed, “there's every reason to think that this strategy will work with higher accuracy in the future when combined with other recent advances,” Stavisky added.

The saga of the bilingual brain implant first began five years ago.

At age 20, a man identified as Pancho became severely paralyzed after having a stroke in the early 2000s. A native Spanish speaker who only learned English as an adult, he could moan and grunt but couldn't articulate words.

Under the leadership of Dr. Edward Chang, Pancho first received a neural implant in February 2019, allowing scientists to start tracking his brain activity. Two years later, the technology had significantly helped restore Pancho's ability to communicate, but only in English.

“What languages someone speaks are actually very linked to their identity,” Chang explained in the journal news release. “And so our long-term goal has never been just about replacing words, but about restoring connection for people.”

After discovering that Pancho's brain showed activity in both languages years after his stroke, the scientists realized they could use that to train a bilingual brain implant.

"We leveraged this finding to demonstrate transfer learning across languages. Data collected in a first language could significantly expedite training a decoder in the second language," Chang's group said in a post on social media.

In 2022, the scientists again used the artificial neural network to train Pancho's brain implant on the distinct neural activity produced by his bilingual communication.

According to the report, Pancho was able to use the bilingual decoding system powering his brain implant to "participate in a conversation, switching between [both] languages on the basis of preference."

The study ultimately offers a glimpse into how this technology has the "potential to restore more natural communication" among bilingual speakers with paralysis, the researchers said.

More information

The American Stroke Association has more on stroke.

SOURCE: Nature Biomedical Engineering, May 20, 2024; NBC News