Shared etiology of phonological memory and vocabulary deficits in school-age children
2013 (English)In: Journal of Speech, Language and Hearing Research, ISSN 1092-4388, E-ISSN 1558-9102, Vol. 56, no 4, 1249-1259 p.Article in journal (Refereed) Published
Purpose: The goal of this study was to investigate the etiologic basis for the association between deficits in phonological memory (PM) and vocabulary in school-age children.
Method: Children with deficits in PM or vocabulary were identified within the International Longitudinal Twin Study (ILTS; Samuelsson et al., 2005). The ILTS includes 1,045 twin pairs (between the ages of 5 and 8 years) from the United States, Australia, and Scandinavia. The authors applied the DeFries-Fulker ( DeFries & Fulker, 1985, 1988) regression method to determine whether problems in PM and vocabulary tend to co-occur because of overlapping genes, overlapping environmental risk factors, or both.
Results: Among children with isolated PM deficits, the authors found significant bivariate heritability of PM and vocabulary weaknesses both within and across time. However, when probands were selected for a vocabulary deficit, there was no evidence for bivariate heritability. In this case, it appears that the PM–vocabulary relationship is caused by common shared environmental experiences.
Conclusions: The findings are consistent with previous research on the heritability of specific language impairment and suggest that there are etiologic subgroups of children with low vocabulary for different reasons, 1 being more influenced by genes and another being more influenced by environment.
Place, publisher, year, edition, pages
American Speech-Language-Hearing Association, 2013. Vol. 56, no 4, 1249-1259 p.
behavior genetics, phonological storage framework, longitudinal, twin, language impairment
IdentifiersURN: urn:nbn:se:liu:diva-96046DOI: 10.1044/1092-4388(2012/12-0185)ISI: 000328266600016OAI: oai:DiVA.org:liu-96046DiVA: diva2:640622