A Hybrid Brain-Computer Interface-Based Mail Client

Figure 6

The GUI of the P300-based speller that is used for text input. Fifty buttons arranged in a 5 by 10 stimuli matrix corresponding to 45 characters and 5 function keys. “CLEAR” is used to clear all of the input characters, “SPACE” is used to input a space, “DEL” is used to delete the last input character, “OK” is used to return to the mail client interface with the input text, and “BACK” is used to cancel the input text and return the user to the mail client interface.