The creation of a brain-computer interface (BCI) has allowed a woman who was paralyzed after a brainstem stroke to talk again, thanks to the expertise of a research team from UC San Francisco and UC Berkeley.  Speech and facial expressions have never before been artificially created from brain signals. Additionally, this system converts the signals into text at a rate of roughly 80 words per minute, which is far faster than solutions that are available commercially. The team aims to bring animation and richness back to those who need help communicating.

“Our goal is to restore a full, embodied way of communicating, which is really the most natural way for us to talk with others. These advancements bring us much closer to making this a real solution for patients.” – Edward Chang, MD, chair of neurological surgery at UCSF

After locating the areas of the brain that are the most important for speech, Chang and his team implanted a paper rectangle made up of 253 electrodes over the surface of a woman’s brain. These electrodes tuned into the brain signals that are usually sent to the muscles in her tongue, jaw, larynx, as well as other muscles in her face and sent them to a bunch of computers she was connected to. The woman worked with the team over many weeks in order to train the system’s Artificial Intelligence algorithms to recognize what she wanted to say, and how. Repeating various phrases from a repertoire of 1,024 words repeatedly was necessary to train the computer to identify the brain activity and patterns connected to the sounds.

“The accuracy, speed and vocabulary are crucial. It’s what gives a user the potential, in time, to communicate almost as fast as we do, and to have much more naturalistic and normal conversations.” – Sean Metzger


“We’re making up for the connections between the brain and vocal tract that have been severed by the stroke. When the subject first used this system to speak and move the avatar’s face in tandem, I knew that this was going to be something that would have a real impact.” –  Kaylo Littlejohn

The development of a wireless version that does not require the user to be physically attached to the BCI is a crucial next step for the team.

“Giving people the ability to freely control their own computers and phones with this technology would have profound effects on their independence and social interactions,” said co-first author David Moses, PhD