A typewriting system operated by head movements, based on home-computer equipment

For persons who cannot move their hands and legs we have designed a relatively inexpensive typewriting system which can be operated by movements of the head. The typewriter is made up of commercially available home computer equipment - i e, a computer including monitor and printer and a headset replacing the mouse. A user-friendly software program has been designed to replace the mouse button and to make this equipment act as a typewriter with simple text-editing features. Some ergonomics aspects of the typewriter set-up and the results of an evaluation of the typewriter by two patients suffering from amyotrophic lateral sclerosis (ALS) are given. Several factors relevant to the design, construction, evaluation and application of the typewriter are discussed.