The light comes from behind to illuminate the keyboard, and I often prop a mirror on the chair in front of her so that I can see her eyes. Often Kim will very obviously be attending to the keyboard, at other times her gaze may wander up and to the side in a fairly characteristic manner, and I wait for her complete this seemingly necessary activity before gently bringing her head back to the midline and asking her to look again at the keyboard. Another Rett Syndrome factor affecting pointing is breath-holding. This may happen frequently during a communication session - Kim uses this to position her headpointer, and on expiration lowers the tip onto the desired key as she relaxes. It is essential to be able to erase mistakes.
Output is a small printed paper tape.
Often the answer is NO, so she continues with the word. So her own feeling of herself in space is limited to her head, hands and a few joints. IF I'M EVEN HIGH OR LOW IN THE ROOM . For Kim, handwringing is a serious distraction and must be prevented during communication, which is fragile. I then hold the Canon so that the keyboard lies in the plane of movement of the tip of Kim's headpointer, and so that the tip starts at the centre of the top row of characters.