Modeling AAC is an evidence-based practice (officially)

Before you say anything — we know. This is an obvious fact to anyone who’s been paying attention in the AAC world for quite some time. However, there are still times when it’s helpful to have clear, scientific evidence to share with those who aren’t, shall we say, on board. Evidence like a recent systematic review, for instance? Voilà!

This new study synthesized the available research on direct teaching strategies** that support symbol learning and aided language expression for AAC users, and found four strategies they identify as “potentially effective.” They looked at 15 studies that met their criteria for participants, intervention type, outcome measures, and study quality.

Important note: They specifically did not look at AAC users with autism.  The studies in the review included children up to age 18, with better receptive than expressive language, and “no more than a moderate intellectual disability.” The most frequent diagnoses represented were cerebral palsy and Down Syndrome.

These four strategies were supported by the evidence:

  1. Aided AAC modeling (8 studies)
  2. Narrative-based interventions (4 studies, limited by small number of participants and variation among studies)
  3. An “eclectic” approach, including increased communication opportunities, modeling, and least-to-most prompting (1 study)
  4. Mand-Model (2 studies) E.g., Child is interested in a ball. Clinician models, “That’s a BALL.” Prompts child to say “Ball,” possibly using a cueing hierarchy. Child gets the ball.

A few things to keep in mind: First, these strategies are not mutually exclusive, and overlap to some degree; they all include some aspect of modeling. Second, we can’t say anything at this point about whether one of these methods is more effective than another, and it could be that certain strategies might work better at specific stages (when a device is first introduced, for example, to teach a specific language skill, or with a very young child). Finally, it’s pretty tricky to make comparisons between studies, since so many different terms can be used for the same, or similar, procedures (modeling, aided language input, aided language stimulation, etc.). Different people define these procedures in different ways—a fixed ratio of statements to questions, for example, or a minimum expectation of how many utterances are also modeled on the device.

Fun Fact! Did you know that there’s a rule of thumb to determine if an intervention can be *officially* considered evidence-based, on the basis of single-subject or small studies? Horner et al. (2005) say you want to find:

  • At least five peer-reviewed studies (well-designed ones!)
  • By at least three different people
  • In at least three geographic locations
  • With at least 20 subjects total

Based on these criteria, and the findings of the review, aided AAC modeling is an evidence-based practice. There wasn’t enough evidence available for the narrative-based, eclectic, or mand-model strategies to meet this threshold.

For systematic review articles like this one, the gold for clinicians is often the big ol’ summary table (Table 1). It’s a quick way to see which of the included studies are directly relevant to YOU, by breaking out details like who the participants were, the AAC systems they used, the type and dosage of the intervention, and the outcome measures. Plus, the authors have already screened these studies for quality, which can be reassuring if you aren’t super confident about assessing this yourself. If you want to learn more about specific intervention procedures for specific clients, this paper has done your searching for you.

**So—not things like communication partner training, which is also good.

Lynch, Y., McCleary, M., & Smith, M. (2018). Instructional strategies used in direct AAC interventions with children to support graphic symbol learning: A systematic review. Child Language Teaching and Therapy, 34(1), 23–36. doi: 10.1177/0265659018755524.