SLEEP-WAKE CONSOLIDATION AND LANGUAGE DEVELOPMENT
Associations Between Sleep-Wake Consolidation and Language Development in Early Childhood: A Longitudinal Twin Study
Ginette Dionne, PhD1,2; Evelyne Touchette, PhD1,3; Nadine Forget-Dubois, PhD1,2; Dominique Petit, PhD4; Richard E. Tremblay, PhD1,5,6,7,8; Jacques Y. Montplaisir, MD, PhD4,6; Michel Boivin, PhD1,2
1Research Unit on Children's Psychosocial Maladjustment, Montreal, Canada; 2School of psychology, Laval University, Québec, Canada; 3Paris Sud Innovation Group of Adolescent Mental Health, INSERM U669, Paris, France; 4Sleep Disorders Centre, Sacré-Coeur Hospital, Montreal, Canada; 5Department of Psychology, University of Montreal, Montreal, Quebec, Canada; 6Department of Psychiatry, University of Montreal, Montreal, Quebec, Canada; 7International Laboratory for Child and Adolescent Mental Health Development, INSERM U669, Paris, France; 8School of Public Health and Population Science, University College Dublin, Dublin, Ireland
The objectives were (1) to assess associations between sleep consolidation at 6, 18 and 30 months and language skills at 18, 30, and 60 months; and (2) to investigate the genetic/environmental etiology of these associations.
Longitudinal study of a population-based twin cohort.
1029 twins from the Quebec Newborn Twin Study.
Measurements and Results:
Sleep consolidation was derived from parental reports of day/night consecutive sleeping durations. Language skills were assessed with the MacArthur Communicative Development Inventory at 18 and 30 months and the Peabody Picture Vocabulary Test at 60 months. The day/night sleep ratio decreased significantly from 6 to 30 months. The 6- and 18-month ratios were negatively correlated with subsequent language skills. Children with language delays at 60 months had less mature sleep consolidation at both 6 and 18 months than children without delays and those with transient early delays. Genetic and regression analyses revealed that the sleep ratio at 6 months was highly heritable (64%) and predicted 18-month (B = −0.06) and 30-month language (B = −0.11) mainly through additive genetic influences (RGs = 0.32 and 0.33, respectively). By contrast, the sleep ratio at 18 months was mainly due to shared environment influences (58%) and predicted 60-month language (B = −0.08) through shared environment influences (RCs = 0.24).
Poor sleep consolidation during the first 2 years of life may be a risk factor for language learning, whereas good sleep consolidation may foster language learning through successive genetic and environmental influences.
Dionne G; Touchette E; Forget-Dubois N; Petit D; Tremblay RE; Montplaisir JY; Boivin M. Associations between sleep-wake consolidation and language development in early childhood: a longitudinal twin study. SLEEP 2011;34(8):987-995.