Eight years ago, a patient lost her power of speech because of ALS, or Lou Gehrig’s disease, which causes progressive paralysis. She can still make sounds, but her words have become unintelligible, leaving her reliant on a writing board or iPad to communicate. Now, after volunteering to receive a brain implant, the woman has been able to rapidly communicate phrases like “I don’t own my home” and “It’s just tough” at a rate approaching normal speech. People without speech deficits typically talk at a rate of about 160 words a minute. Even in an era of keyboards, thumb-typing, emojis, and internet abbreviations, speech remains the fastest form of human-to-human communication. The new research was carried out at Stanford University.
The BCI that researchers work with a small pad of sharp electrodes embedded in a person’s motor cortex, the brain region most involved in movement. This allows researchers to record activity from a few dozen neurons at once and find patterns that reflect what motions someone is thinking of, even if the person is paralyzed. Researchers wanted to know if neurons in the motor cortex contained useful information about speech movements, too. That is, could they detect how subject T12 was trying to move her mouth, tongue, and vocal cords as she attempted to talk? These are small, subtle movements, and just a few neurons contained enough information to let a computer program predict, with good accuracy, what words the patient was trying to say.
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