Using a high-probability behavioral momentum sequence to teach functional vocabulary to children with autism

The prognosis for verbal communication in children with autism has improved considerably in light of recent advances in language intervention technologies. However, the literature indicates that the rate of initial word acquisition in these children is typically slow and some children failed to respond to language intervention techniques that are currently available. One documented method to accelerate the development of first words is to systematically incorporate responses that are readily acquired by and are already available to the child, such as pretreatment phonemes or nonverbal behaviors, into the overall intervention package. Substantial research also suggests that antecedent interventions based on task interspersal or behavioral momentum might be especially promising in enhancing a continuum of communication behaviors in children with developmental disabilities. The current study sought to integrate these converging lines of research on the systematic incorporation of readily available responses and a momentum-based procedure to facilitate initial verbal communication in young nonverbal children with autism within the context of Pivotal Response Treatment (PRT), a naturalistic motivational intervention. The key variable of this investigation was the presentation of a sequence of teaching trials involving high-probability words from the child immediately preceding the presentation of low-probability target word stimuli. A multiple baseline design across four participants was employed to assess the influence of the high-probability intervention on the following experimental measures: (1) level of functional verbal responding to target word stimuli, (2) number of words during probes, (3) vocabulary diversity during probes, (4) type and quality of functional vocabulary use, and (5) observed affect during play interactions. Data indicate increases in participants' functional verbal communication and positive affect as a result of the high-probability sequence procedure. Additionally, these gains were successfully maintained when the high-probability sequence was withdrawn from the standard procedures of PRT and at one-month follow-up. Findings are discussed in terms of theoretical and clinical implications for difficult-to-teach children with autism, as well as future research directions.