The effect of context priming and task type on augmentative communication performance.

Augmentative and Alternative Communication (AAC) devices include special purpose electronic devices that generate speech output and are used by individuals to augment or replace vocal communication. Word prediction, including context specific prediction, has been proposed to help overcome barriers to the use of these devices (e.g., slow communication rates and limited access to situation-related vocabulary), but has not been tested in terms of effects during actual task performance. In this study, we compared AAC device use, task performance, and user perceptions across three tasks, in conditions where the AAC device used either was, or was not, primed with task specific vocabularies. The participants in this study were adults with normal physical, cognitive, and communication abilities. Context priming had a marginally significant effect on AAC device use as measured by keystroke savings; however, these advantages did not translate into higher level measures of rate, task performance, or user perceptions. In contrast, there were various statistically significant process and performance differences across task type. Additionally, results for two different emulations of human performance showed significant keystroke savings across context conditions. However, these effects were mitigated in actual performance and did not translate into keystroke savings. This indicates to AAC device designers and users that keystroke-based measures of device use may not be predictive of high level performance.