Content area
Full Text
Purpose: This investigation aimed to apply the dosage framework proposed by Warren, Fey, and Yoder (2007) to variations of milieu language teaching intervention strategies to explore how each of the dosage parameters (i.e., dose, dose form, dose frequency, total duration, and cumulative intervention intensity) was reported in the located empirically based applications with learners between birth and 23 years of age.
Method: A systematic search located existing studies that implemented a milieu teaching intervention for children with developmental disabilities. Dosage data were then extracted from 42 studies along with study characteristics and participant characteristics.
Results: Only 37.8% of empirical investigations provided a clear definition of treatment intensity and reported the full range of dosage parameters, thus making it difficult to compare the results across investigations. Of the investigations that reported on all dosage parameters, the majority were single-case design as opposed to group design studies.
Conclusions: Given the limited reporting of dosage parameters in existing studies, there is a need for closer attention to reporting this information in early communication intervention protocols. Replication and customization of interventions for learners experiencing developmental disabilities will only be possible with additional empirical examination of dosage parameters.
Key Words: dosage parameters, milieu intervention, autism, developmental disabilities
Warren, Fey, and Yoder (2007) described a sys- tem to quantify the intensity of communication intervention dosage, which they referred to as treatment intensity· They proposed that, "[i]t is time to begin the creation of a systematic research base examining this critically important dimension of intervention efficacy-the effects of different intervention intensities on communica- tion and language development" (p. 71). Without a general set of dosage parameters that investigators adhere to in de- scribing the implementation of an intervention, it becomes impossible to separate the relative contributions of dosage from curricular content in any meaningful comparison of the efficacy of two or more distinct communication inter- vention approaches. A logical dosage analogy can be made in considering medications prescribed by physicians. With medicine, not only is it important to consider the best type of drug to prescribe, but it is also imperative to prescribe the correct dosage. Dosing studies in the field of pharmacology recognize the importance of parameters like form (liquid/ pill), delivery mechanism (oral/injection), frequency (daily/ hourly), and duration (1...