2019 ASHA Research Symposium: Mabel L. Rice, What Studies of Twins Tell Us About Specific Language Impairment in Children: Twinning Effects & Heritability at 2, 4, 6, and 16 Years of Age
mediaposted on 2020-11-23, 18:39 authored by Mabel L. Rice
This presentation video is from the Research Symposium at the 2019 Annual Convention of the American Speech-Language-Hearing Association held in Orlando, FL.
The abstract for the accompanying article is below. This article is part of the JSLHR Forum: Advances in Specific Language Impairment Research & Intervention.
Purpose: This review article summarizes a program of longitudinal investigation of twins’ language acquisition with a focus on causal pathways for specific language impairment (SLI) and nonspecific language impairment in children at 4 and 6 years with known history at 2 years.
Method: The context of the overview is established by legacy scientific papers in genetics, language, and SLI. Five recent studies of twins are summarized, from 2 to 16 years of age, with a longitudinal perspective of heritability over multiple speech, language, and cognitive phenotypes.
Results: Replicated moderate-to-high heritability is reported across ages, phenotypes, full population estimates, and estimates for clinical groups. Key outcomes are documentation of a twinning effect of risk for late language acquisition in twins that persists through 6 years of age, greater for monozygotic than dizygotic twins (although zygosity effects disappear at 6 years); heritability is greater for grammar and morphosyntax than other linguistic dimensions, from age 2 years through age 16 years, replicated within twin samples at subsequent age levels and across twin samples at age 16 years.
Conclusion: There is consistent support for legacy models of genetic influences on language acquisition, updated with a more precise growth signaling disruption model supported by twin data, as well as singleton data of children with SLI and nonspecific language impairment.
Rice, M. L. (2020). Causal pathways for specific language impairment: Lessons from studies of twins. Journal of Speech, Language, and Hearing Research, 63(10), 3224–3235. https://doi.org/10.1044/2020_JSLHR-20-00169
This article stems from the 2019 Research Symposium at ASHA Convention, which was supported by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health under Award R13DC003383. Preparation of this review article and much of the research reported here was supported by National Institutes of Health Grants R01DC001803 and R01DC005226 (PI: M. L. Rice), as well as Grant T32DC000052 as doctoral student support (PI: M. L. Rice).
specific language impairmentSLIASHA Conventiontwinstwin studiescausalcausepathwaysreviewsystematic reviewlongitudinallanguageacquisitionnonspecific language impairmentchildrenadolescentsgeneticsheritabilityspeechspeech-language pathologySLPcognitivephenotypeageclinical groupoutcomestwinning effectriskmonozygoticdizygoticgrammarmorphosyntaxlinguisticlegacy modelinfluencecommunicationdisorderLinguistic Processes (incl. Speech Production and Comprehension)