Optimal Dosage Characteristics of Recasting for Developmental Language Disorder: A Scoping Review

Purpose: The purpose of this scoping review was to map and summarize currently available evidence about optimal dosage of recasting for developmental language disorder (DLD). Method: A systematic search of databases was completed, including Web of Science, Medline via OvidSP, PsycINFO, Cochrane Library, and Scopus. The inclusion criteria comprised the involvement of DLD intervention, the use of recasting alone or predominantly, and systematic manipulation of one or more dosage characteristics of recasting with the remaining parameters consistent across groups. Single-case experimental design studies were also included. Results: A total of 1,289 studies were included in the review, but only four articles met the criteria. Stratification analysis of an expanded set of 32 publications was then performed for effective dosage values, according to the way recasting was implemented. The effective quantitative dosage of recasting that has often been used is either an intervention duration > 8 weeks including a recast rate > 1.4/min within 30-min sessions, twice per week without high variability input, or a 5-week intervention including a recast rate of 0.8/min within 30-min sessions, five times per week with high variability input. Conclusions: Differences in the way dosage has been described and manipulated in the existing literature mean that the optimal dosage characteristics of recasting for DLD remain unknown. We propose ways to conceptualize dose and dose frequency to avoid ambiguities within the current framework of dosage. This review identifies ways that dosage characteristics of recasting for DLD can be manipulated and reported when designing interventions. Supplemental Material: https://doi.org/10.23641/asha.30015529