Comparing the Effects of Speech-Generating Device Display Organization on Symbol Comprehension and Use by Three Children With Developmental Delays.

Purpose: Three children ages 3;6 to 5;3 with developmental and language delays were provided experience with a traditional grid-based display and a contextually organized visual scene display on a speech-generating device to illustrate considerations for practice and future research in augmentative and alternative communication assessment and intervention.

Method: Twelve symbols were taught in a grid display and visual scene display using aided input during dramatic play routines. Teaching sessions were 30 minutes a day, 5 days a week for 3 weeks. Symbol comprehension and use was assessed pre and post 3 weeks of experience.

Results: Comprehension of symbol vocabulary on both displays increased after 3 weeks of experience. Participants 1 and 2 used both displays largely for initiation. Participant 3 had limited expressive use of either display.

Conclusions: The methods used in this study demonstrate one way to inform individual differences in learning and preference for speech-generating device displays when making clinical decisions regarding augmentative and alternative communication supports for a child and their family. Future research should systematically examine the role of extant comprehension, symbol experience, functional communication needs, and the role of vocabulary type in the learning and use of grid displays versus visual scene displays.