Children's history of speech-language difficulties: genetic influences and associations with reading-related measures.
OBJECTIVE
This study examined (a) the extent of genetic and environmental influences on children's articulation and language difficulties and (b) the phenotypic associations between such difficulties and direct assessments of reading-related skills during early school-age years.


METHODS
Behavioral genetic analyses focused on parent-report data regarding the speech-language skills of 248 twin pairs (M = 6.08 years) from the Western Reserve Reading Project. In addition, phenotypic associations between children's speech-language status and direct assessments of early reading-related abilities were examined through hierarchical linear modeling (HLM).


RESULTS
Probandwise concordance rates and intraclass tetrachoric correlations indicated high heritability for children's difficulties in expressive language and articulation, with estimates of .54 and .97 accordingly. HLM results indicated that children with histories of speech-language difficulties scored significantly lower than unaffected children on various measures of early reading-related abilities.


CONCLUSIONS
Results from the parent-report survey provided converging evidence of genetic effects on children's speech and language difficulties and suggest that children with a history of speech-language difficulties are at risk for lower performance on early reading-related measures. The extent of risk differed across measures and appeared greatest for children who demonstrated a history of difficulties across articulation, expressive language, and receptive language. Implications for future genetic research and clinical practice are discussed.
DeThorne
Laura Segebart
LS
Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, IL 61820, USA. lauras@uiuc.edu
Hart
Sara A
SA
Petrill
Stephen A
SA
Deater-Deckard
Kirby
K
Thompson
Lee Anne
LA
Schatschneider
Chris
C
Davison
Megan Dunn
MD
D001184:Articulation Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D002648:Child; D003147:Communication Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D004410:Dyslexia / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D007806:Language Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D008297:Male; D010641:Phenotype; D012720:Severity of Illness Index; D013064:Speech Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D014427:Twins / Q000235:genetics*