Longitudinal Stability in Genetic Effects on Children's Conversational Language Productivity PurposeThe authors examined the longitudinal stability of genetic and environmental influences on children's productive language sample measures during the early school-age years.MethodTwin study methodology with structural equation modeling was used to derive univariate estimates of additive genetic (A), shared environmental (C), and nonshared environmental (E) effects on language measures at ... Article
Article  |   June 01, 2012
Longitudinal Stability in Genetic Effects on Children's Conversational Language Productivity
 
Author Affiliations & Notes
  • Laura Segebart DeThorne
    University of Illinois at Urbana–Champaign
  • Nicole Harlaar
    The Mind Research Network, Albuquerque, NM
  • Stephen A. Petrill
    The Ohio State University, Columbus
  • Kirby Deater-Deckard
    Virginia Polytechnic Institute and State University, Blacksburg
  • Correspondence to Laura DeThorne: lauras@illinois.edu
  • Editor: Janna Oetting
    Editor: Janna Oetting×
  • Associate Editor: Diane Loeb
    Associate Editor: Diane Loeb×
Article Information
Language
Article   |   June 01, 2012
Longitudinal Stability in Genetic Effects on Children's Conversational Language Productivity
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 739-753. doi:10.1044/1092-4388(2011/11-0014)
History: Received January 14, 2011 , Accepted October 19, 2011
 
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 739-753. doi:10.1044/1092-4388(2011/11-0014)
History: Received January 14, 2011; Accepted October 19, 2011
Web of Science® Times Cited: 2

PurposeThe authors examined the longitudinal stability of genetic and environmental influences on children's productive language sample measures during the early school-age years.

MethodTwin study methodology with structural equation modeling was used to derive univariate estimates of additive genetic (A), shared environmental (C), and nonshared environmental (E) effects on language measures at each of 2 time points, based on 487 twins at the 1st-grade time point and 387 twins at the 2nd-grade time point. To address questions of stability over time, the authors used longitudinal latent factor analysis.

ResultsStability in the Conversational Language factor was accounted for almost entirely by shared genetic effects between 1st and 2nd grade, meaning no new genetic effects were observed at the 2nd time point. In contrast, nonshared environmental effects were entirely time point specific, meaning whatever nonshared environmental influences were operating at the first time point were not influencing individual variation in the language factor at the second time point.

ConclusionThe discussion in this article centers on possible candidates for both genetic and nonshared environmental effects as well as implications for clinical practice and future research.

Acknowledgments
The Western Reserve Reading Project is supported by National Institute of Child Health and Human Development Grants HD38075, HD46167, and HD050307. In addition, transcription and analyses have been supported by the American Speech-Language-Hearing Foundation New Investigator Award; the University of Illinois at Urbana–Champaign Campus Research Board; and the Children, Youth and Families Consortium at The Pennsylvania State University. Interdisciplinary collaborations have been enhanced by the American Speech-Language-Hearing Association Advancing Academic–Research Careers (AARC) Award. In addition, we sincerely appreciate the time and effort of all participating families and affiliated research staff. Students responsible for language sample transcription of HV3 included, but were not limited to, Tanya Cooper, Lisa Mellman, Kelly O'Connor, Carly Sullivan, Elena Turner, Amy Woodrum, and Amy Van Nada.
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