Figure 1. An AEIOU alphabet board. To use the board, an assistant calls out the colors and the patient signals the required color by a pre-selected eye movement (usually upward). The assistant then calls out the letters sequentially on that line, allowing the patient to select the letter by their eye movement. Chosen letters are written down to formulate a sentence, question, or answer. With experience, the board may not be required. Different combinations of letters have been used by others, often arranged in order of their frequency.