Laura Segebart Dethorne

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BACKGROUND Studies have suggested genetic and environmental influences on overall level of early reading whereas the larger reading literature has shown environmental influences on the rate of growth of early reading skills. This study is the first to examine the genetic and environmental influences on both initial level of performance and rate of(More)
The current study involved 281 early-school-age twin pairs (118 monozygotic, 163 same-sex dizygotic) participating in the ongoing Western Reserve Reading Project (S. A. Petrill, K. Deater-Deckard, L. A. Thompson, & C. Schatschneider, 2006). Twins were tested in their homes by separate examiners on a battery of reading-related skills including phonological(More)
The present study combined parallel data from the Northeast-Northwest Collaborative Adoption Projects (N2CAP) and the Western Reserve Reading Project (WRRP) to examine sibling similarity and quantitative genetic model estimates for measures of reading skills in 272 school-age sibling pairs from three family types (monozygotic twins, dizygotic twins, and(More)
We examined the genetic and environmental contribution to the stability and instability of reading outcomes in early elementary school using a sample of 283 twin pairs drawn from the Western Reserve Reading Project. Twins were assessed across two measurement occasions. In Wave 1, children were either in kindergarten or first grade. Wave 2 assessments were(More)
Despite the common use of mean length of utterance (MLU) as a diagnostic measure, what it actually reflects in terms of linguistic knowledge is relatively unclear. This study explored the extent to which variance in MLU could be accounted for by a measure of expressive vocabulary and a measure of morphosyntax in a group of 44 typically-developing children,(More)
We examined the Simple View of reading from a behavioral genetic perspective. Two aspects of word decoding (phonological decoding and word recognition), two aspects of oral language skill (listening comprehension and vocabulary), and reading comprehension were assessed in a twin sample at age 9. Using latent factor models, we found that overlap among(More)
The present study used correlation analyses to examine the extent to which language abilities are associated with nonverbal IQ in 30 children with language impairment, age 4-8 years. After controlling for age, nonverbal IQ demonstrated medium associations with composite measures of both semantic and morphosyntactic abilities (r = .46 and .45 respectively).(More)
We examined mothers' ratings of children's affective and behavioral aspects of approach tendencies and links with overt aggressive behavior problems while considering the genetic etiology of these processes. Approach/positive anticipation (AP), frustration/anger (FA), and overt aggression in 4-9-year-olds were assessed using mothers' reports in a diverse(More)
This study used a cross-lagged twin design to examine reading achievement and independent reading from 10 to 11 years (n = 436 twin pairs). Reading achievement at age 10 significantly predicted independent reading at age 11. The alternative path, from independent reading at age 10 to reading achievement at age 11, was not significant. Individual differences(More)
The genetic and environmental sources of variance in mothers' and fathers' ratings of child temperament in middle childhood were estimated and compared. Parents of 88 MZ twin pairs and 109 same-sex DZ twin pairs completed a temperament questionnaire. For Effortful Control, significant genetic and environmental effects were indicated across mothers' and(More)