Amount of physical control: How is your level and range of head control? Mouth? Facial expressions, and which ones? Vision issues? How many hours a day would you be using the system? In what orientations – sitting upright, or laying bed? In a wheelchair?
Verbal ability: Do you have any ability to speak? If yes, are you at least partially able to issue vocal commands to the computer?
Are the limitations temporary (such as due to a recent injury) versus expected to last for a longer term?
Would the user be comfortable continuously using the system for the number of hours they need to use it every day to achieve their goal? (See next factor below) This is especially important for wearable gadgets such as eyewear and headbands that some users may find uncomfortable to use for more than 30 minutes at a time.
