The Influence of Quantitative Intervention Dosage on Oral Language Outcomes for Children With Developmental Language Disorder: A Systematic Review and Narrative Synthesis

Abstract

Purpose The aim of this study was to examine the degree to which quantitative aspects of dosage (dose, dose frequency, and total intervention duration) have been examined in intervention studies for children with developmental language disorder (DLD). Additionally, to establish the optimal quantitative dosage characteristics for phonology, vocabulary, and morphosyntax outcomes. Method This registered review (PROSPERO ID CRD42017076663) adhered to PRISMA guidelines. Search terms were included in seven electronic databases. We included peer-reviewed quasi-experimental, randomized controlled trial or cohort analytical studies, published in any language between January 2006 and May 2020. Included articles reported on participants with DLD ( M = 3–18 years); oral language interventions with phonology, vocabulary, or morphosyntax outcomes; and experimental manipulation or statistical analysis of any quantitative aspect of dosage. Studies were appraised using the Cochrane risk-of-bias tool. Results Two hundred forty-four articles reported on oral language interventions with children with DLD in the domains of interest; 13 focused on experimentally/statistically manipulating quantitative aspects of dosage. No article reported phonological outcomes, three reported vocabulary, and eight reported morphosyntax. Dose frequency was the most common characteristic manipulated. Conclusions Research is in its infancy, and significant further research is required to inform speech-language pathologists in practice. Dosage characteristics are rarely adequately controlled for their individual effects to be identified. Findings to date suggest that there is a point in vocabulary and morphosyntax interventions after which there are diminishing returns from additional dosage. If dose is high (number of learning opportunities within a session), then the literature suggests that session frequency can be reduced. Frequent, short sessions (2/3 × per week, approximately 2 min) and less frequent, long sessions (1 × per week, approximately 20 min) have yielded the best outcomes when composite language measures have been used; however, replication and further research are required before clinicians can confidently integrate these findings into clinical practice. Supplemental Material https://doi.org/10.23641/asha.13570934

To Game or Not to Game? Efficacy of Using Tablet Games in Vocabulary Intervention for Children with DLD

“…Marulis and Neuman [27] pointed out that vocabulary training targeted to a discrete set of skills (like in the present study, where we trained and evaluated a closed set of target words) might involve shorter-term intervention activities than those that are designed to enhance more global skills. More recently, Frizelle et al [21] reported a systematic review on the influence of dosage on the language outcomes of children with DLD. They could only include three studies looking at dosage and vocabulary training.…”

“…The vocabulary intervention consisted of symbolic play sessions wherein the SLPs presented the 22 target words in a narrative, and the target words were also elicited via natural interaction and language facilitation strategies. The intervention was developed according to best evidence for word learning, supporting strategies such as interactive focused stimulation [19] and frequent exposure to the target words in different narrative contexts [14,20,21]. To control the content of the two intervention conditions, we developed vocabulary scripts for each session for use by the SLPs.…”

Evaluating two different dose frequencies and cumulative intervention intensities to improve past tense production for early school‐aged children with developmental language disorder

“…Since this time, there have been advancements in the area, but still very few studies compare the same dose form across other intervention parameters (e.g., dose frequency, total intervention duration, cumulative intervention intensity) to demonstrate efficacy and efficiency. A recent systematic review and narrative synthesis concluded that when dose, total intervention duration, and cumulative intervention intensity (in hours) is controlled, there is no advantage to increasing dose frequency to improve morphosyntax for young children with DLD (Frizelle et al, 2021). For example, an efficacy study of 16 4-5-year-old children revealed that children receiving enhanced conversational recasting intervention in spaced (three 10-min sessions daily) versus massed (one 30-min session daily) conditions performed comparably at postintervention testing points (Meyers-Denman & Plante, 2016).…”

“…These results suggest that this explicit intervention is efficacious for treating regular past tense for early school-aged children with DLD. Considering the relative lack of evidence evaluating grammar interventions in different dose conditions (see Frizelle et al, 2021), and the reported preference to provide more intervention rather than less (see Finestack & Satterlund, 2018), re-analysis of previously reported data comparing dose frequency may provide valuable information regarding dosage to optimise efficacy.…”

“…If so, this may suggest that cumulative intervention intensity is more important to consider than spacing when delivering this intervention. Indeed, Frizelle et al (2021) concluded that 'more is not always better' (p. 752), since the evidence base indicates a point of diminishing returns in terms of dose frequency and the total number of intervention sessions.…”