Highly Generalizable Spelling Using a Silent-Speech BCI in a Person with Severe Anarthria

Speech is one of the most natural and efficient ways to communicate and is a fundamental aspect of daily life. Assistive brain-computer interface (BCI) technology has the potential to restore communication to people who cannot speak or type due to paralysis. Recent advances have enabled users to communicate by attempting to speak, type, or handwrite intended messages. Another approach may be to spell out intended words and sentences with a BCI that is controlled by natural attempts to speak. As part of an ongoing clinical trial we recorded low- and high-frequency electrocorticography (ECoG) signals from a 128-channel high-density array implanted over the sensorimotor cortex of a brainstem-stroke survivor with severe anarthria (the inability to articulate speech) and quadriparesis while he silently attempted to spell out words and sentences using the NATO phonetic alphabet.