Determinants of Rate in Communication Aids for the Non-Vocal Motor Handicapped

Abstract

A framework is proposed to account for the generic design factors which interact to determine output rate in the use of communication aids for patients with neuromotor speech deficit. These factors, C (cost in language units per word), L (code length in motor acts per unit) and T (time per motor act) are in a trade-off relationship so that an increment or decrement in any one is not sufficient to determine the overall effect on rate of communication. Data is presented from 2 studies to illustrate ways in which this interaction may operate. Implications are drawn for nonvocal communication device design.