On 15 May 2024, Caltech neuroscientists are making promising progress toward showing that a device known as a brain–machine interface (BMI), which they developed to implant into the brains of patients who have lost the ability to speak, could one day help all such patients communicate by simply thinking and not speaking or miming.
In 2022, the team reported that their BMI had been successfully implanted and used by a patient to communicate unspoken words. Now, reporting in the journal Nature Human Behaviour, the scientists have shown that the BMI worked successfully in a second human patient.
Credit: Adapted from Edmondson, Laura R., and Hannes P. Saal
In the current study, the researchers first trained the BMI device to recognize the brain patterns produced when certain words were spoken internally, or thought, by two tetraplegic participants. This training period took only about 15 minutes. The researchers then flashed a word on a screen and asked the participant to “say” the word internally. The results showed that the BMI algorithms were able to predict the eight words tested, including two nonsensical words, with an average of 79 percent and 23 percent accuracy for the two participants, respectively.
The researchers point out that the BMIs cannot be used to read people’s minds; the device would need to be trained in each person’s brain separately, and they only work when a person focuses on the particular word.
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