Optimizing menu selection process for single-switch manipulation

Abstract

Single-switch manipulation is considered as a model for optimizing a menu selection task for physically challenged users. We have applied a short-cyclic hierarchical structure with three levels and three alternatives as a basic layout for symbol input and imaging. A user can make use of the triple-stroke or the long-stroke technique when the button is held down for extended period. It allows to jump over one of menu levels or to cut the cycle. We designed algorithm for adaptive scan interval and have applied it for text entry. Long-stroke technique significantly reduces the number of strokes and increases typing speed. The preliminary tests with able-bodied participants showed an average typing speed of more than 20 signs per minute after one-hour training. Adaptive scan interval could be useful for applications that require periodic time correction depending on user performance. Algorithm for adaptive scan interval and the coupled issues are considered in detail. © Springer-Verlag 2004.