Fig. 3.

Real-time spelling. a Visual rendition of one trial in the training session. Note that the frequency-phase combinations shown in the first panel are for exposition purposes and were not shown during the actual experiment. b The interface for the spelling session showed the word to be spelled, as well as the current set of letters that had been sequentially selected by the subject in their attempt to spell out the word. Eight of the crosses have been replaced with the characters required to spell the word and one cross was replaced with a backspace icon which could be used to undo a previous selection. No cues are given and the stimulation length was reduced to 2 s. c Post hoc simulation of the decoding accuracies with shorter stimulation lengths. The table shows the performance of the subjects during the real-time mind-spelling session