Watch the video: Brain implant – Avatar lets woman speak again after stroke.
In 2005, at the age of 30, a Canadian woman suffered a brainstem stroke. In an instant, she lost control of the muscles in her body, including the muscles needed to produce speech. Today, Ann is helping researchers at the University of San Francisco and the University of Berkeley develop a new brain-computer technology that could one day allow people like her to communicate with other people via a digital avatar that resembles a person. To do this, a team of researchers implanted a wafer-thin rectangle of 253 electrodes on the surface of their brains in areas crucial for language. The electrodes intercept the brain signals that would have traveled to the muscles in Ann’s lips, tongue, jaw, larynx, and face without the stroke. A connector attached to Ann’s head sends these signals through wires to a number of computers. For weeks, Ann worked with the team to train the system’s artificial intelligence algorithms to recognize their brain signals for speech. Instead of training the artificial intelligence on whole words, the researchers developed a system that decodes words from smaller components called phonemes. These are the subunits of language that make spoken words the same way letters make up written words. For example, “Hello” consists of four phonemes: “HH”, “AH”, “L” and “OW”. With this approach, the computer only had to learn 39 phonemes to decipher any English word. To synthesize Ann’s speech, the team developed a speech synthesis algorithm, which they adapted from a recording of Ann’s speech at her wedding to sound like her voice before the injury. Now she looks forward to the day when her daughter can hear her too. “My daughter was a year old when I got injured. It’s like she doesn’t know Ann…She has no idea what Ann sounds like.” For Ann, helping develop the technology has changed her life. She explains: “Participating in this study has given me a sense of purpose, I feel like I’m contributing to society. It feels like I have a job again. It’s amazing that I’ve lived for this long this study has enabled me to truly live while I am alive!”