Thank you for the kind words! A brain computer interface is a device that records brain signals, and allows people with paralysis to control objects in their e

Thank you for the kind words! A brain computer interface is a device that records brain signals, and allows people with paralysis to control objects in their environment using their thoughts. Here, we demonstrate how the BCI can help restore communication to a man with ALS using only neural signals recorded from the speech-related motor areas of the brain (ventral precentral gyrus). As he tries to speak, our decoding system translates the neural activity into words on a screen. Hence, to answer your question, we are only using brain signals to determine what he's trying to say. The microphone is not involved in interpreting his speech at all (and in fact, speech-to-text algorithms applied to the audio signals are nonsensical). One can hear him speak in the supplementary videos in the NEJM paper, and in the video produced by UC Davis. The eye-tracker is used to help control the GUI, much like an able-bodied person would use a mouse.