Exploring the Impact of Language Facilitation Strategies on Verbal Language in Two Year-Old, Minimally Verbal Children with ASD

Background:  

Approximately 25 percent of individuals with an ASD are considered nonverbal (Autism Speaks, 2014).  Limited research focuses on minimally verbal children with ASD for multiple reasons: the exclusion of children with limited verbal abilities in intervention studies, the highly variable nature of this population with no single set of defining characteristics, and the difficulty finding assessments to identify appropriate level of functioning (Tager-Flusberg & Kasari, 2013). However, Kasari et al., (2014) recently demonstrated that effective interventions could improve the quality and quantity of verbal language in school-age, minimally verbal children. This research study focused on the impacts of language-based strategies often provided by speech language pathologists (SLPs) on the spoken language of children with ASD. SLPs are often the first line of referral for children later diagnosed with ASD due to early communication concerns. However, most of these therapists, especially those working through state-funded early intervention programs, have limited access to autism-specific intervention models (Stahmer et al., 2005). As a result, general language facilitation strategies are often implemented. To our knowledge, no study has measured the effects of these commonly used strategies on the verbal language in minimally verbal children with ASD. 

Objectives:  

The purpose of this study was to measure the effects of focused stimulation, vertical structuring, and expansions on verbal language in minimally verbal children with ASD.

Methods:  

Three children were recruited from a university-based Autism Clinic if they met the following inclusion criteria: (1) clinical diagnosis of ASD (2) under 36 months of age (3) range of 5-21 words; and (4) no prior direct language intervention. Using a multiple baseline AB design across participants, the intervention techniques of focused stimulation, vertical structuring, and expansions were implemented in a play-based setting.  Each intervention session targeted functional words chosen by a Child Interest Survey and family goals. The sessions lasted 20 minutes, twice a week for 8 weeks. The MacArthur Bates Communicative Development Inventories (MCDI; Fenson et al., 2007) was administered pre- and post- intervention in order to assess receptive and expressive vocabulary. Words produced by the child and the strategy demonstrated by the investigator were coded from video recordings of each intervention session.

Results:  

Intervention has concluded for all participants and data coding is underway. Coding and data analysis are complete for one child thus far and indicated that the total number of different words produced increased and remained above baseline. Expansion was associated with the most words produced followed by vertical structuring then focused stimulation. MCDI post-testing yielded the following findings. Participant one, 32 months on intervention onset, produced 48 more words and understood 76 more words following intervention. Participant two, 27 months, produced 105 more words and understood 149 more words following the intervention. Participant three, 34 months, produced 147 more words and understood 91 more words following intervention. While this design does not allow causative interpretations, the language gains indicated on the MCDI are striking. 

Conclusions:  

These results contribute to the growing literature regarding effective interventions for minimally verbal children with autism.