Comment by dewarrn1

EEG recording is an alternative that would outlast the potential disease-related degradation of eye movements. Manny Donchin gave a brown bag at UIUC about the possibilities of using this approach to support communication by ALS patients many years ago. It's clever: they use the P300 marker to index attention/intention. I do not recall whether he and his colleagues ever commercialized the tech. I believe that this publication is representative: https://doi.org/10.1016/j.clinph.2005.06.027