Relationship of Individual Task-Specific Functional Brain Connectivity with Sex Differences in Developmental Dyslexia

Previous EEG studies using graph analysis have revealed altered functional brain networks in children with developmental dyslexia (DD). The influence of sex on these networks within this childhood disorder remains unclear. The study emphasizes the importance of considering sex and individual differences by investigating brain connectivity in 8-year-old children (42 controls and 72 children with DD, half girls) during a task involving low- and high-contrast discrimination of low-spatial frequency illusion (LSFI). Understanding these variations is crucial for elucidating the neurobiological underpinnings of developmental disabilities. Control children showed sex differences in association networks, while children with DD exhibited them in sensorimotor networks. The control boys’ α, β2-frequency functional networks were more integrated than control girls in low-contrast LSFI and in β and γ2-networks in high-contrast LSFI. Boys exhibited stronger anterior connectivity (language, visual motion), while girls showed stronger posterior connectivity (visuospatial, visuomotor attention). There was a notable overlap in association networks between boys and girls. Sex-related differences were pronounced in the γ2 frequency sensorimotor, and association cortical networks exhibited dispersion in both hemispheres for boys and in the left hemisphere for girls (both contrast LSFIs). Boys with DD exhibited hubs in α-sensorimotor networks (low-contrast LSFI) and β1-networks (high-contrast LSFI) in the right brain hemisphere, while girls’ hubs with DD were in the left hemisphere. The differing rates of cortical network maturation between sexes with DD during childhood contribute to variations linked to disruptions in brain network development, even within sensorimotor networks. The study showed that this task enhanced even minor individual differences in functional connectivity characteristics and revealed subtle differences in brain connectivity, especially in children with DD.