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A brain implant being developed by a team of Duke University neuroscientists may allow people to communicate using nothing but their thoughts.
The implant is made up of 256 microscopic brain sensors placed onto a postage stamp-sized piece of flexible, medical-grade plastic, the researchers explained.
To test the implant, the researchers recruited four patients who were already undergoing brain surgery for some other condition.
Due to the limited amount of time they had to test the brain implant while in the operating room, the scientists had to move quickly.
“I like to compare it to a NASCAR pit crew,” said Gregory Cogan, Ph.D., a professor of neurology at Duke University’s School of Medicine and one of the lead researchers involved in the project.
“We don’t want to add any extra time to the operating procedure, so we had to be in and out within 15 minutes. As soon as the surgeon and the medical team said ‘Go!’ we rushed into action and the patient performed the task.”
The task was a simple listen-and-repeat activity. Participants heard a series of nonsense words, like “ava,” “kug,” or “vip,” and then spoke each one aloud. The device recorded activity from each patient’s speech motor cortex as it coordinated nearly 100 muscles that move the lips, tongue, jaw, and larynx.
Afterwards, Suseendrakumar Duraivel, the first author of the new report and a biomedical engineering graduate student at Duke, took the neural and speech data from the surgery suite and fed it into a machine learning algorithm to see how accurately it could predict what sound was being made, based only on the brain activity recordings.
While the decoder recognized the “g” in the sound “gak” 84% of the time, overall it was accurate just 40% of the time.
“That may seem like a humble test score, but it was quite impressive given that similar brain-to-speech technical feats require hours or days-worth of data to draw from,” the researchers wrote.” The speech decoding algorithm Duraivel used, however, was working with only 90 seconds of spoken data from the 15-minute test.”
The problem, according to report, is that “the best speech decoding rate currently available, which clocks in at about 78 words per minute. People, however, speak around 150 words per minute.”
“We’re at the point where it’s still much slower than natural speech,” Viventi told Duke Magazine, “but you can see the trajectory where you might be able to get there.”
Cogan explained the motive for their work on developing this new brain implant, saying, “There are many patients who suffer from debilitating motor disorders, like ALS (amyotrophic lateral sclerosis) or locked-in syndrome, that can impair their ability to speak. But the current tools available to allow them to communicate are generally very slow and cumbersome.”
Now, with a $2.4 million grant from the National Institutes of Health, they hope they will be able to remedy that problem someday soon.
The full research report was published in the journal Nature Communications.