Comparing two modes of AAC intervention for children with autism

The purpose of this study was to compare the relative effectiveness of two modes of Augmentative and Alternative Communication (AAC) for children with autism and related developmental disabilities. In order to achieve the stated purpose of this study, the following research questions were addressed: (1) are there differences in acquisition rates for requests taught using Picture Exchange Communication System (PECS) v. Speech Generating Device (SGD)? ; (2) do children show a preference for one mode over the other?; and (3) are there differences in perceived social validity of PECS v. SGD? This study employed an alternating treatment design within each subject to compare the effectiveness of PECS and SGD for teaching communicative requesting. Results indicate that both modes of AAC intervention were effective across participants. For acquisition, SGD training required fewer sessions, trials, and resulted in higher correct responses for two of three participants. However, all three participants showed comparable acquisition with PECS and SGD training. It would appear that the prompt and the time delay instructional procedures were equally effective in teaching PECS and SGD. The children preferred one mode over the other when given choices. Two children showed a preference for PECS, and one child showed a preference for SGD. Social validity data suggests that raters preferred SGD training.