Poster Slam Session E, Thursday, August 22, 2019, 3:30 - 3:45 pm, Finlandia Hall, Brenda Rapp
Disentangling the contribution of family risk on reading precursors in pre-readers
Lauren Blockmans1, Fumiko Hoeft2,3,4, Jan Wouters1, Pol Ghesquière1, Maaike Vandermosten1;1KU Leuven, 2University of Connecticut, 3University of California, San Francisco, 4Haskins Laboratories
Developmental dyslexia has a prevalence of 7% and a heritability rate of 40%. The chance to develop dyslexia is thus larger in children with a family risk (FR). Previous longitudinal studies identified specific predictors in pre-readers for developing dyslexia. Phonological skills such as phonological awareness (PA) and rapid automatized naming (RAN) combined with letter knowledge (LK) are considered robust predictors (Snowling and Melby-Lervåg, 2016). Additionally, though less consistently, pre-reading deficits have been observed in auditory processing and speech perception skills, more specifically in discriminating amplitude changes at speech sound onset, i.e. rise time (RT), and speech perception in noise (SPIN). However, these studies relied on the heritability rate and selected mostly FR pre-readers to obtain a sufficient large number of dyslexics, yet they do not represent the entire dyslexic population. Due to this bias towards FR children, it remains unknown whether the same predictors are applicable to children without a FR. Neuroimaging studies have suggested that decreased response to auditory stimuli (Hakvoort et al. 2015) and speech (Vandermosten et al. under revision) are related to FR instead of later reading outcomes. This is supported by a structural neuroimaging study demonstrating that differences in planum temporale, known to be involved in speech processing, are related to FR of dyslexia (Vanderauwera et al. 2018). Therefore, we aim to disentangle the contribution of FR on speech perception and auditory precursors. First, we selected pre-readers based on FR, defined as having a first-degree relative with dyslexia, and searched for individually matched pre-readers without a FR. Then we created groups based on their cognitive risk (CR), namely performance below percentile 30 for two of the three predictors (PA, RAN, LK). This resulted in four groups of pre-readers: 18 with FR and CR (FR⁺CR⁺), 27 with FR but without CR (FR⁺CR⁻), 34 without FR and CR (FR⁻CR⁻) and 8 without FR and with CR (FR⁻CR⁺). Since the latter group was very small because of our selection procedure, we performed a second large-scale screening in 1224 children to recruit pre-readers with a CR. Based on the same criteria as in the first screening, we were able to increase the size of our groups with a CR. This resulted in a sample of 157 five-year-olds (81♂/76♀): 34 FR⁺CR⁺, 27 FR⁺CR⁻, 34 FR⁻CR⁻ and 62 FR⁻CR⁺. Once selected, they performed a RT and SPIN task. The fitted GLM revealed a significant main effect of FR in the SPIN task (p = 0.007), showing poorer speech perception skills in FR+ than FR-, and a significant main effect of CR in the RT task (p = 0.007), showing poorer auditory processing skills in CR+ than CR-. No other significant main and interaction effects were observed. These results suggest that impaired auditory processing at the pre-reading stage does not depend on FR. In contrast, and more in line with previous neuroimaging studies, FR does influence speech perception performance of pre-readers. This study is part of a longitudinal project allowing to further disentangle FR contributions on the neural level in the near future.
Themes: Disorders: Developmental, Reading
Method: Behavioral
Poster E9