van Bergen, E. 1, 2 , de Jong, P. F. 2 , Maassen, B. 3 & van der Leij, A. 2
1 University of Oxford, UK
2 University of Amsterdam, the Netherlands
3 University of Groningen, the Netherlands
Which children go on to develop dyslexia? The combination of investigating child characteristics and family characteristics sheds light on the constellation of risk factors that can ultimately lead to dyslexia. We present a longitudinal study following the progress of children with and without a family history of dyslexia. The study examines plausible preschool risk factors and their specificity for predicting reading development. Furthermore, it goes beyond testing the effect of having a parent with dyslexia to quantify the cognitive risks passed on from both parents to their offspring. Participants included at-risk children with (n = 50) and without (n = 82) dyslexia in Grade 3 and controls (n = 64). First, we found impairments in phonological awareness, rapid naming, and letter knowledge in at-risk kindergartners who later developed dyslexia, and mild phonological-awareness deficits in at-risk kindergartners without subsequent dyslexia. We also examined the specificity of these preliteracy skills. Although these skills were also related to later arithmetic, associations with later reading were stronger. Second, the literacy environment at home was comparable among groups. Third, literacy skills of both parents were related to their offspring?s reading skills. Children from families in which both parents experienced literacy difficulties were 2½ times more likely to develop dyslexia than children from families with only one affected parent. This suggests that at-risk children who do and who do not develop dyslexia differ in genetic predisposition. Intervention can best be targeted at kindergartens with the highest liability, which are those who do poorly on preliteracy tasks and whose parents have literacy difficulties. Literacy abilities of parents might be viewed as indicators of their offspring?s liability for literacy difficulties, since parents provide their offspring with their genetic and environmental endowment. We propose an intergenerational multiple deficit model in which both parents confer cognitive risks.