Effects of multiple interventions for reducing vocal stereotypy: Developing a sequential intervention model

Despite the availability of several interventions designed to reduce engagement in vocal stereotypy, few studies have compared two or more interventions together. Consequently, practitioners have limited amount of data to make informed decisions on whether an intervention may be more suitable than another to begin treating vocal stereotypy. The purpose of the study was to address this limitation by examining the direct and collateral effects of multiple interventions in 12 individuals with autism and other developmental disabilities in order to guide the development of a sequential intervention model. Using single-case experimental designs, we conducted a series of four experiments which showed that (a) noncontingent music generally produced more desirable outcomes than differential reinforcement of alternative behavior, (b) differential reinforcement of other behavior reduced vocal stereotypy in two participants for whom noncontingent music had failed to do so, (c) the addition of simple prompting procedures may enhance the effects of the interventions, and (d) the effects of noncontingent music may persist during sessions with extended durations. Based on these results, we propose a sequential intervention model to facilitate the initial and subsequent selection of an intervention most likely to reduce vocal stereotypy while producing desired collateral outcomes.