Co-Principal Investigator: Peredo, Tatiana

Purpose: The goal of this study is to examine the efficacy of EMT en Español, a cultural and linguistic adaptation of Enhanced Milieu Teaching (EMT), to improve the language and related school readiness skills of young Spanish-speaking children with receptive and expressive language delays. Early language delays impact children's later communicative, social, behavioral, and academic skills and put children at risk for persistent language impairment. Therefore, early language intervention, particularly intervention utilizing caregivers to provide language development support for their children in the home, is crucial. Yet, there is limited research on such interventions for Spanish-speaking children with language delays and applications of current evidence-based intervention are likely limited due to linguistic and cultural differences. This project aims to provide needed research on early language intervention with this population. EMT is an existing naturalistic communication intervention that has demonstrated efficacy with English-speaking toddlers. Pilot data suggest that the Spanish adaptation, EMT en Español, leads to improvements in caregiver-child communication during interactions, increases linguistic input to facilitate language learning, and improves the diversity and rate of child talk. In the current project, the research team will investigate the efficacy of EMT en Español to improve children's immediate and longer-term expressive and receptive language skills as well as caregivers' use of natuaralistic language teaching strategies. They will also explore the effects of the intervention on children's language and related school readiness skills, examine the long-term effects of the intervention on cross-linguistic (English and Spanish) outcomes, and calculate the cost-effectiveness of the intervention.

Project Activities: In this project, the research team will examine the efficacy of EMT en Español using a randomized controlled trial, with child-caregiver dyads randomized into intervention and control groups. Assessments of children and caregivers will be collected before the intervention begins, immediately after the intervention ends, and at 6-month and 12-month follow-up time points. Analyses will examine the impact of the intervention on observed vocabulary during child-caregiver interactions, standardized child expressive and receptive language assessments, parent implementation of intervention strategies with their child in natural contexts, and later school readiness outcomes, including various language skills and executive functioning.

Products: The primary product of this project will be evidence of the efficacy of EMT en Español for young Spanish-speaking children with receptive and expressive language delays. The project will also result in a final dataset to be shared, peer-reviewed publications and presentations, and additional dissemination products that reach education stakeholders such as practitioners and policymakers.

Structured Abstract

Setting: The study will take place in homes and community settings where early intervention programs, funded by Part C of the Individuals with Disabilities Education Act (IDEA), take place in Tennessee.

Sample: Participants will include 84 children aged 30-36 months and their Spanish-speaking caregivers. Children will demonstrate expressive and receptive language delays, with no additional disability, and come from low-income families.

Intervention: EMT en Español is the Spanish linguistic and cultural adaptation of Enhanced Milieu Teaching (EMT), a naturalistic language intervention that promotes the use of new language forms using environmental arrangement, responsive interaction strategies, language modeling and expansions, and systematic prompting procedures to teach functional spoken language. Therapists work with children and teach caregivers communication, interaction, and language support strategies, as well as specific book-sharing strategies. EMT en Español is provided in Spanish and includes cultural adaptations for Spanish-speaking children and families. The selection of language targets will follow typical Spanish language rules and development (for example, taking into account that Spanish-speaking children acquire verb use and different inflections earlier than English-speaking children). There will be a total of 36 sessions, half consisting of the therapist working directly with the child and half focused on caregiver training.

Research Design and Methods: The intervention will be evaluated through a randomized controlled trial in which child-caregiver dyads are randomized into the intervention or control group. Both groups will continue to receive their usual services, but the intervention group will have services supplemented with the EMT en Español. Therapists from the research team will provide participants in the intervention group with 36 sessions of EMT en Español over a period of 6 months. The research team will collect child and caregiver assessment data at baseline, the end of the intervention, 6 months after intervention, and 12 months after intervention. Data on therapists' fidelity of implementation will also be collected during the intervention period. The data collected will address the primary research questions about the effects of the intervention on expressive and receptive vocabulary during interactions and story retell; the effects on caregiver use of intervention strategies, such as use of more rich language targets; and whether caregiver strategy use mediates the impact of the intervention on children's outcomes. They will also be used to investigate longer-term effects on children's language and related school readiness skills, including executive functioning, and on English as well as Spanish language skills. The relative costs and benefits of the intervention will also be investigated. Family enrollment into the study will occur on a rolling basis over the first 4 years of the project, follow-up data will be collected throughout the study, and final data analyses will occur in the final year.

Control Condition: Families in the control condition will receive their current business-as-usual early intervention services, if any. These may include the state's Part C program, Early Head Start, or no services.

Key Measures: For child language outcomes, the research team will use an adult-child interaction observational measure, standardized English-Spanish bilingual versions of the Receptive One Word Picture Vocabulary Test and Expressive One Word Picture Vocabulary Test, and a narrative retell task in both Spanish and English. In addition, because it's only normed for older ages, the Bilingual English Spanish Assessment will be used at the 12-month follow up to examine phonology, morphosyntax, and semantics in both languages. For executive functioning, the research team will use the Behavior Rating Inventory of Executive Function-Preschool Version Spanish and direct child assessments, including the snack delay and Head-Shoulder-Knees-Toes task. Measures that will be used to screen children for eligibility include the Leiter-R and Preschool Language Scale-5th Edition Spanish. Fidelity of implementation will be measured by coding videotaped intervention sessions to capture therapist use of EMT en Español while interacting with the child, therapist teaching of the intervention strategies to caregivers, and caregiver use of intervention strategies during daily routines, play, and book sharing. A risk index for each child — to be used as a covariate in analyses — will be calculated based on caregiver-reported demographic information such as family composition, caregiver education, and household income, as well as a maternal depression scale.

Data Analytic Strategy: Multivariate regression analyses will be used to examine the immediate and longer-term impact of EMT en Español on children's language skills during caregiver-child interactions, children's narrative retell, and caregivers' use of naturalistic language teaching strategies. Researchers will also use regression analyses to explore whether the intevention moderates the relationship between baseline Spanish expressive vocabulary skills and both their Spanish and English expressive vocabulary skills at follow up. To examine whether parent use of intervention strategies mediates the impact of the intervention at follow up, the research team will use mediation analysis with bootstrapping. To explore long-term effects of the intervention on school readiness skills (including standardized language assessments and executive functioning), the research team will use latent growth modeling and multivariate regression. Finally, the ingredients method will be used to analyze implementation costs and cost-effectiveness ratios will be calculated based on implementation costs and the effects of the intervention on primary outcomes.

Related Projects: An Efficacy Trial of Milieu Teaching Language Intervention in Preschoolers with Language Disorders (R324A090181); An Efficacy Trial of J-EMT: Enhanced Milieu Teaching Language Intervention plus Joint Attention, Engagement and Regulation Intervention for Toddlers with Autism (R324A150094)