Toddlers who demonstrate significant speech impairments and use augmentative and alternative communication (AAC) often demonstrate concomitant expressive language impairments. These toddlers receive AAC intervention due to difficulties with speech production at the motor level, and receive language intervention due to difficulties with vocabulary development at the linguistic level. One language intervention approach with a large base of evidence supporting efficacy in young children who have language delays, but do not use AAC, is responsivity education combined with focused stimulation. Another language intervention approaches with a large base of evidence supporting efficacy in young children who use AAC is responsivity education combined with aided AAC modeling. However, the effectiveness of responsivity education and focused stimulation has not been systematically studied, nor has the approach been compared to responsivity education and focused stimulation with the addition of AAC modeling in toddlers who use AAC.
A challenge of language intervention is to provide effective and efficient treatment for the expressive language impairment. To address this critical challenge with toddlers who use AAC, the current investigation compared the effectiveness and efficiency of these language intervention approaches in teaching new vocabulary production to toddlers between the ages of two and three who received AAC intervention. Specifically, the study examined the possible added value of including AAC modeling to an intervention involving responsivity education and focused stimulation. The study used an adapted alternating treatment design across participants. Four 2-year-old toddlers, who used AAC to communicate, participated in the study. One toddler used a visual grid, manual sign, and word approximations/words to communicate; one toddler used manual sign and word approximations/words to communicate; one toddler used a communication board, manual sign, and word approximations/words to communicate; and a final toddler used a flip chart and word approximations/words to communicate.
The results of the study provided preliminary evidence that the language intervention approach of responsivity education and focused stimulation was more effective for improving the vocabulary production in three of four participants in the study. The added value of including AAC modeling in the intervention resulted in more effective vocabulary production with the fourth participant. In addition, the results of the investigation provided preliminary evidence that the language intervention approach of responsivity education and focused stimulation was more efficient for improving the vocabulary production in two of the four participants in the study. The added value of AAC modeling in the intervention resulted in more efficient vocabulary production for the third participant. Neither intervention approach was efficient with the fourth participant. Possible factors affecting the results of the study, theoretical and clinical implications, limitations, and future directions for research are discussed.
