As music therapists, many of us utilize the Picture Exchange Communication System (PECS) with our clients who have limited expressive communication skills. A recent study looked at the extent to which this communication system was successfully generalized to the non-treatment environment.

Yoder and Lieberman (2010) examined past data collected to determine if children in the PECS group generalized learned skills into different situations. Thirty-six children were randomly assigned into two groups (one being PECS) and results indicated that children in the PECS group significantly increased used of PECS after 6-months of treatment in an environment different from the treatment environment.

In this situation they were only testing the use of the symbols as communication, not the discrimination of the correct symbol. The authors recognize that a discrimination study may be more interesting, but they wanted to see if the basic steps were generalizing. Nevertheless, it’s good to see significant improvements after 6-months of treatment.

This study did not address the improvements in communication of the two groups compared (i.e., did the second group improve in non-PECS communication), which appears to be the topic of an earlier study published by the authors. Another thing I would like to have seen in this study is an explanation of the group sizes. One group had 19 and the other 17 – in a randomly distributed study I would expect to see 18 children in each group. Why the difference in group sizes? The authors report no attrition.

To answer these questions I went back tot he 2006 study mentioned earlier. In the original study the other treatment (Responsive Education and Prelinguistic Milieu Teaching) was shown to be more effective then PECS in object exchanges and joint attention. PECS felicitated more object requests. Although the authors don’t say why the groups were different sizes, they do show that 120 children were screened for this study and only 36 met the criteria.  Wow. That shows the huge difference in this population and why it is so hard to study anything with children who are on the autism spectrum.

This study says four things to me: 1) PECS may improve object requests in young children with autism, 2) it is important to look at skill improvement both within treatment and in a generalized environment, 3) I believe that it is important to look at the literature on techniques we are using in music therapy in EBP, and 4) sometimes you need to dig to get the the whole story.

References:

Yoder PJ, & Lieberman RG. (2010). Brief Report: Randomized test of the efficacy of picture exchange communication system on highly generalized picture exchanges in children with ASD. J Autism Dev Disord., 40(5), 629-32. PMID: 19904596