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.
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.
Entities:
Keywords:
behavior genetics; language impairment; longitudinal; phonological storage framework; twin
Authors: Richard K Olson; Janice M Keenan; Brian Byrne; Stefan Samuelsson; William L Coventry; Robin Corley; Sally J Wadsworth; Erik G Willcutt; John C Defries; Bruce F Pennington; Jacqueline Hulslander Journal: Sci Stud Read Date: 2011
Authors: Brian Byrne; William L Coventry; Richard K Olson; Stefan Samuelsson; Robin Corley; Erik G Willcutt; Sally Wadsworth; John C Defries Journal: J Neurolinguistics Date: 2009-05 Impact factor: 1.710
Authors: Elizabeth I Pierpont; Erica Kesin Richmond; Leonard Abbeduto; Sara T Kover; W Ted Brown Journal: J Neurodev Disord Date: 2011-10-13 Impact factor: 4.025
Authors: Göran B W Söderlund; Jakob Åsberg Johnels; Bodil Rothén; Ellen Torstensson-Hultberg; Andreas Magnusson; Linda Fälth Journal: Brain Behav Date: 2021-06-06 Impact factor: 2.708