AAC Vocabulary: Categories or Core? How about BOTH, and a few other things...

This question was posed this week on the ASHA Special Interest Group for AAC.  It was such a good question and research packed answer that I thought I’d share it.  The reply is from an SLP who specializes in content for the Dynavox devices, however, the actual research is listed for you to read and decide for yourself.  Very interesting!

“I was wondering if anyone has run across any specific research that demonstrates the effectiveness of a language-based selection interface (i.e. LAMP or Prentke-Romic software) versus that of a category-based selection interface (i.e. Dynavox or Proloquo2Go)? “  (SLP in Washington)

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Replied to by Linnea McAfoose, Dynavox Technologies

“What a great question!  Knowing the research is an important part of evidence based practice.  I think there are two different parts to your question:  vocabulary organization/interface and vocabulary type.  Here are some references for each.  I’ll apologize in advance for the length of this post and disclose up front that I am an SLP who works for DynaVox.

Research directly comparing vocabulary organization/interface

1.       Light, Drager, et. al (2004)¹, found that typically developing 4 and 5 year olds find it easier to locate target vocabulary organized incategories (based on part of speech, scheme, or a schematic scene, all of which are used on DynaVox devices) than using iconic encoding (e.g., Unity from PRC).  This was without any training and accuracy wasn’t necessarily very high for any of the conditions.  With training, however, all but one of the children made gains in accuracy.  Significantly greater gains were seen for the three category based conditions than for iconic encoding.

2.       Drager, Light, et. al (2003, 2004)^2,3 also looked at the type of categorical organization was easier for children to learn and use.  They found that typically-developing young children (2 ½ and 3 year olds) were better able to navigate to and locate specific vocabulary when it was organized in a visual scene (called schematic scene display or contextual scene; used in DynaVox products) than when it was organized in a grid.

Research reflecting the types of vocabulary we need to communicate what we want, where we want, and how we want (as an SLP, this is really exciting to me J)

1.       Instead of needing either a core word vocabulary or categorical vocabulary (the two distinctions in your question), AAC systems need to provide access to both!  At all ages, we need a combination of pre-programmed messages and vocabulary we can use to create novel messages.  We need access to messages that can get us into conversations efficiently and allow us to communicate precisely within the interactions.

a.       Lieven (2003)⁴ provides support for the idea that much of what young children say (½ to ⅔) is made up of utterances they have previously used with one or several words that change.  For example, the chunk “Where’s Annie’s…” can be followed by any number of single words like “plate,” “hat,” or “book,” based on the situation.  Basically, young children use consistent chunks of language in which they modify a word or two based on the situation/need. 

a.       In her dissertation, Clendon (2006)⁵ concludes that we require a combination of formulaic (prestored) and creative (core and spelling) to ensure we can communicate what we want both efficiently and precisely. 

b.      In a review of multiple studies with adults, Todman (2008)⁶ concluded “AAC system design should reflect conversational goals and include effective whole-utterance features needed to support both transactional and social conversation. It must also be recognized that word construction features are also needed to meet some communication goals.”

2.       DynaVox provides this combination of vocabulary in our software (InterAACt framework).  Here are two recent articles specifically discussing InterAACt

a.       McCoy et. al (2011)⁷ suggests that AAC systems “should allow the user to quickly navigate to desired messages, but should also help the user remember what messages are available and allow quick editing of existing messages or composing new messages.”  She specifically cites InterAACt as a an example of software that allows for seamless switching between pre-stored messages (topics, topic messages, Phrases, QuickFires) and the tools needed to create new messages (core, word lists, keyboards).

b.      Kent-Walsh and Binger (2011)⁸ report a case study about a child who needs a communication device to help her expressive language reach the level of her receptive language.  They state she needed  “an SGD that was durable, was portable, had a dynamic display, pre-contained age-appropriate pre-programmed vocabulary and morpho-syntactic software, and had onscreen keyboard capabilities to support literacy development.”   InterAACt was the communication software recommended to meet these needs.

¹Light, J., Drager, K., McCarthy, J., Mellott, S., Millar, D., Parrish, C., Parsons, A., Rhoads, M., Ward, M., & Welliver, M. (2004). Performance of Typically Developing Four and Five Year Old Children with AAC Systems using Different Language Organization Techniques. Augmentative and Alternative Communication, 20, 63-88.

²Drager, K., Light, J., Speltz, J., Fallon, K., & Jeffries, L. (2003). The performance of typically developing 2 ½ -year-olds on dynamic display AAC technologies with different system layouts and language organizations. Journal of Speech Language and Hearing Research, 46, 298 – 312.

Drager, K., Light, J., Carlson, R., D’Silva, K., Larsson, B., Pitkin, L., & Stopper, G. (2004).  Learning of dynamic display AAC technologies by typically developing 3-year-olds: effect of different layouts and menu approaches, Journal of Speech, Language, and Hearing Research,  47 , 1133–1148.

⁴Lieven, E., Behrens, H., Speares, J., & Tomasello, M. (2003). Early Syntactic Creativity: A Usage-based Approach. Journal of Child Language, 30, 333-370. 

⁵ Available at https://cdr.lib.unc.edu/indexablecontent/uuid:93d1ba1c-4f99-40f3-b4ca-7287159c1315?dl=true

⁶Todman, J., Alm, N., Higginbotham, J., & File, P. (2008). Whole Utterance Approaches in AAC, Augmentative and Alternative Communication, 24(3), 235-254. 

⁷McCoy, K., Hoag, L., & Bedrosian, J. (2011).  Next generation utterance based systems:  what do pragmatic studies tell us about system design? Perspectives in Augmentative and Alternative Communication, 20, 57-63.

⁸Kent-Walsh, J. & Binger, K. (2011).  Technology as a language tool: augmentative and alternative communication in the classroom. Perspectives on School-Based Issues, 12, 28-34.”