A subject wearing an electrode cap (Electro-Cap International, Inc.) attends to the 6 × 6 matrix of items (i.e. letters and numbers) displayed on a 20” monitor at his bedside. Lower left inset: the 6 × 6 matrix and the gray ‘text-to-spell’ bar showing the word to be spelled (‘BROWN’) and the target letter for the first trial, the letter ‘B’, in parentheses at the end of the word. In this example, a group of four items is flashing according the checkerboard (CB) format (22). To encourage attention to the target item, the subject is asked to count the number of times it flashed. Lower right inset: the 16-channel electrode montage and the standard 8-channel subset (marked with ‘X’s).