Epidemiology, etiology, and pathways to DLD: The role of late talking in linguistically and culturally diverse children - The objective of this proposal is to establish a multidisciplinary Clinical Research Center (CRC) on Developmental Language Disorders (DLD). Through the CRC, we propose to identify and estimate the prevalence of DLD (and Late Talking, LT) in a linguistically and culturally representative cohort of young children representative of the general population of the Houston Metropolitan Statistical Area (HMSA). To sample the targeted population of children aged 18-24 months (who will form the sample upon which cases will be ascertained), Core C (Recruitment and Retention) will work with the Texas Children’s Hospital (TCH) pediatric clinic network, the city’s largest organization of pediatric health clinics and hospitals. The children will be assessed for language development status and classified as Late Talkers (LTs) or not Late Talkers (non-LTs) for sampling purposes. For Project 1 (Prevalence), a TCH population sample (n ~ 3,600) will be used to identify a CRC cohort of about 2,400 children in the first 18 months of the study, half of whom (n~1,200) will have screened as LTs and half as non-LTs (n~1,200). This cohort will be followed until the children are 48-59 months of age and assessable for DLD in Project 1. Project 2 (Etiology) will investigate social and genetic determinants for LT and DLD (macro-phenotypes). In Project 3 (Pathways), a subcohort of children speaking Spanish-, English-, or both (n=300) will participate in a longitudinal study of developmental pathways of LT and DLD and their convergence/divergence; these pathways will be characterized with developmentally traced motor, cognitive, and linguistic indicators (micro-phenotypes). Sophisticated longitudinal designs, data management, and statistical analyses are supported by Core B (Data). Core A (Administration) explicitly addresses communication and coordination across projects, progress monitoring, and quality control, thus promoting team effectiveness, usage of the Cores, and synergy of the Projects. The central theme of the proposed CRC is “Evaluating Sources of Heterogeneity and Risk Factors in DLD.” The representativeness of the population of the HMSA makes it an ideal location for investigating heterogeneity and risk factors across different languages, cultures, and socioeconomic strata. This heterogeneity culminates in an aggregate indicator assessed when the children are at least 4 years old, namely school readiness. To understand social, genetic, cognitive, and linguistic factors that predict and characterize DLD and prepare children for school, individual and group differences substantiating the heterogeneity of DLD will be systematically studied from multidisciplinary perspectives.” This theme is refined through three synergistic Projects, three well-organized and efficient Cores, and three Specific Aims on DLD, LT, and their relations: (1) Implement large-scale LT and DLD prevalence studies; (2) Implement converging projects to characterize LT and predict DLD and (3) Conduct multidisciplinary research anchored by strong methodologies, enhanced by complex analytics, and supported by an expert team of clinical researchers.
