Purpose: The aim of this systematic review was to examine the empirical evidence on interventions for late talkers between 18 and 42 months according to type of intervention approach (direct, indirect, and hybrid), reporting of intervention elements, and outcomes for receptive and expressive vocabulary.
Method: This review was registered with PROSPERO and followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Eleven databases were systematically searched with 34 intervention studies involving 1,207 participants meeting criteria. Studies were categorized as using a direct, indirect, or hybrid intervention approach, then examined according to intervention elements, vocabulary outcomes, as well as reported tools and type of score used to evaluate outcomes.
Results: Across 34 studies, nine used a direct intervention approach, 10 an indirect intervention approach, and 14 a hybrid intervention approach. One study compared direct and hybrid intervention approaches. All indirect and hybrid approaches included parent training; direct approaches did not. The type and degree of reporting of other intervention elements, as well as the tools and type of score used to evaluate outcomes, varied within and across approaches. Overall, improvements in expressive vocabulary were reported by 93% of studies, with variable results for the nine studies reporting receptive vocabulary outcomes.
Conclusions: The direct, indirect, and hybrid intervention approaches were typified by specific intervention elements; however, there was diversity in how other elements comprising the approaches were arranged. When making decisions about which intervention approach to use, clinicians need to be mindful of the differences among approaches, how they discuss those differences with parents, and which approaches and elements might be best suited to individual children and their families.
Supplemental material: https://doi.org/10.23641/asha.21291405.