The Impact of Intervention Dose Form on Oral Language Outcomes for Children With Developmental Language Disorder.

Purpose The aim of this study was to extract key learning from intervention studies in which qualitative aspects of dosage, dose form, have been examined for children with developmental language disorder (DLD)-in vocabulary, morphosyntax, and phonology domains. This research paper emerged from a pair of systematic reviews, aiming to synthesize available evidence regarding qualitative and quantitative aspects of dosage. While quantitative aspects had been experimentally manipulated, the available evidence for dose form (tasks or activities within which teaching episodes are delivered) was less definitive. Despite this, the review uncovered insights of value to DLD research. Method A preregistered systematic review (PROSPERO ID: CRD42017076663) adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was completed. Included papers were quasi-experimental, randomized controlled trial, or cohort analytic studies, published in any language between January 2006 and May 2019; oral language interventions with vocabulary, morphosyntax, or phonology outcomes; and participants with DLD (M = 3-18 years). The intention was to include papers in which dose form was experimentally manipulated or statistically analyzed, while quantitative dosage aspects were controlled, such that definitive conclusions about optimal dose form could be drawn and gaps in the evidence identified. Results Two hundred and twenty-four papers met the above inclusion criteria; 27 focused on dose form. No study controlled for all quantitative aspects of dosage such that we could effectively address our original research questions. Despite this, key points of learning emerged with implications for future research. Conclusions There is tentative evidence of advantages for explicit over implicit instruction and of the benefits of variability in input, elicited production, and gestural and other visual supports. With careful design of dose form, there is potential to design more efficient interventions. Speech-language pathology research would benefit from an agreed taxonomy of dose form components and standardized reporting of intervention studies, to enable cross-study comparisons and a systematic accrual of knowledge to identify optimal dose form for clinical application.

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

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.

Why Clinicians Choose Their Language Intervention Approach: An International Perspective on Intervention for Children with Developmental Language Disorder.

PURPOSE: Considerable progress has been made in recent years in generating external evidence underpinning interventions for children with developmental language disorder (DLD), but less is known about the practitioner decision-making process underpinning such interventions and whether such decisions are context specific or are internationally generalizable. METHODS: An online survey about clinical practice was developed by members of COST Action IS1406, an EU-funded research network, which included representation from 39 countries. The participants were 2,408 practitioners who answered questions in relation to their decision making for a specific child of their choosing with DLD. Analysis of open-ended questions was undertaken, and data were converted into codes for the purpose of quantitative analysis. RESULTS: Although a wide range of intervention approaches and rationales were reported, the majority of responses referenced a client-centred approach. Level of functioning was used as a rationale only if a child had severe DLD. Practitioners with university level education or above were less likely to report basing intervention on client-centred factors. A number of differently named interventions with variable theoretical and empirical underpinnings were used in different countries. CONCLUSIONS: Specific client and practitioner characteristics have an impact on the intervention approaches and rationales adopted across countries. A limited number of practitioners reported use of external scientific evidence, which suggests that there should be more initiatives in basic training of practitioners and continuing professional development to encourage the uptake of scientific evidence-based practice.