A paralyzed man with locked-in syndrome (conscious but unable to move a muscle) has “spoken” three different vowel sounds using a voice synthesizer, Boston University neuroscientists report.

An electrode implanted into a brain area that controls the movements of the vocal cords and tongue that underlie speech feeds the firing signals of several dozen neurons into an external decoder that recognizes three vowels, using audio feedback to the patient. A next-generation decoder could produce whole words in three to five years.