Frøydis Morken|Turid Helland|Kenneth Hugdahl|Karsten Specht
Reading in dyslexia across literacy development: A longitudinal study of effective connectivity
University of Bergen|University of Bergen|Haukeland University Hospital|University of Bergen|Haukeland University Hospital|University of Bergen
dyslexia literacy disorder affecting efficient acquisition reading writing skills disorder neurobiological origin due developmental nature longitudinal studies dyslexia essence however relatively scarce present study took longitudinal approach cortical connectivity brain imaging data reading tasks children dyslexia children typical reading development participants followed repeated measurements preliteracy 6 years old emergent literacy 8 years old literacy 12 years old stages using dynamic causal modelling dcm analysing functional magnetic resonance imaging fmri data even though longitudinal studies effective connectivity typical reading knowledge studies previously investigated issues relation dyslexia set model brain reading network involving five cortical regions inferior frontal gyrus precentral gyrus superior temporal gyrus inferior parietal lobule occipitotemporal cortex using dcm connectivity measures calculated connection model measures analysed using factorial anova results showed difference groups centred connections going inferior frontal gyrus two connections occipitotemporal cortex three connections five connections typical group showed stable decreasing connectivity measures dyslexia group hand showed marked upregulation occipitotemporal connections downregulation inferior frontal gyrus connections 6 years 8 years followed normalization 8 years 12 years interpret delay dyslexia group developing preliteracy emergent literacy stages delay could possibly detrimental literacy development age 12 statistically significant difference connectivity groups differences literacy skills still present fact larger measured younger ages