Poster B42, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Right lateralization of white matter tracts in infants with a genetic risk of developmental dyslexia
Clarisa Carruthers1, Xi Yu1,2, Jennifer Zuk1,2, Jade Dunstan1, Joseph Sanfilippo1, P. Ellen Grant1,2, Nadine Gaab1,2,3; 1Boston Children's Hospital, 2Harvard Medical School, 3Harvard Graduate School of Education
Dyslexia is highly heritable and several dyslexia susceptibility genes have been identified to date. These have been shown to be important for early brain development in utero. Previous studies have revealed atypical structural and functional characteristics in the left-hemispheric reading network in individuals with developmental dyslexia (DD) and/or family history of DD as early as infancy. It has been suggested that possible compensatory pathways could form in the right hemisphere in dyslexic readers, which might be driven by genetic and environmental factors. However, the emerging process of this alternative network is largely unknown. Here, we investigated the association between right-hemispheric white matter structure and genetic risk of DD in early development in 47 infants (ages 4-18 months), 24 with a family history of DD (FHD+) and 23 without (FHD-). Fractional anisotropy (FA) in the right superior longitudinal fasciculus (RSLF), right arcuate fasciculus (RAF), and right inferior longitudinal fasciculus (RILF) were quantified at various nodes using an automated fiber quantification (AFQ) method. Two-sample t-tests were conducted to compare white matter density between FHD+ and FHD- infants at every node in the RSLF, RAF, and RILF. Higher FA was observed in the RILF and RSLF in FHD+ infants compared to FHD- infants, whereas the RAF did not show significant differences between these two groups. The present findings demonstrated higher white matter integrity in the right hemisphere in infants at risk for DD, suggesting that a right lateralized network for language/reading might start to emerge as early as infancy.
Topic Area: LANGUAGE: Development & aging