A study on the verification of AAC graphic symbols Focusing on nouns, adverbs, and verbs

Abstract

Objectives: Verifying graphic symbols in an accurate and timely manner is essential for individuals with severe communication difficulties to be able to produce words, phrases, and sentences effectively in augmentative and alternative communication (AAC) systems. In order to provide empirical data for AAC evidence-based practice, the current study investigated whether the part-of speech (POS) of target symbols and the congruency between a word and a symbol affected the verification process. Methods: Thirty-three healthy young adults (mean age=26.85 years, SD=6.96) participated in the symbol verification task. They were asked to judge whether the graphic symbols were matched with written words composed of nouns, adverbs, and verbs. The data was analyzed using a repeated measures analysis of variance. Results: The POS significantly affected the response time: participants judged noun symbols faster than the other two symbol types. There was no difference in the response time between adverbs and verbs. In addition, participants showed a significantly longer response time in the incongruent condition than the congruent condition for the noun symbols and verb symbols. Conclusion: The results provide support for the high iconicity of noun symbols, which affects the performance of graphic symbol verification. This study also suggests that cognitive load increases when filtering out non-target graphic symbols, which requires a strategy to enhance the efficiency of target symbol selection. © 2017 Korean Academy of Speech-Language Pathology and Audiology.