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White-matter differences across cognitive profiles in developmental dyslexia
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
Nilgoun Bahar1, Margo Kersey1,2, Pedro Pinheiro-Chagas1, Maya Bardorf1, Ally Radford1, Nick Wellman1, Ezra Mauer1, Sarah M. Inkelis1, Christa Pereira1, Zachary Miller1, Maria Luisa Mandelli1, Maria Luisa Gorno-Tempini1; 1University of California, San Francisco, 2University of Michigan
Introduction: Developmental dyslexia (DD) is a heterogeneous neurodevelopmental condition in which similar reading difficulties may arise from distinct neurocognitive mechanisms. In a recent data-driven investigation (Pinheiro-Chagas et al., 2025), we identified two cognitive profiles in children with persistent DD: one characterized by weaknesses in executive functioning and processing speed (EF-DD), and another typified by difficulties in verbal short-term memory and lexical retrieval (STM-DD). Despite these differences, both groups showed comparable difficulties in decoding and reading comprehension. Here, we examined whether these cognitive profiles are associated with distinct patterns of white-matter integrity in the brain. Specifically, we hypothesized that the STM-DD group would show greater alterations in left-lateralized language-related pathways, whereas the EF-DD group would show alterations in frontoparietal and cognitive-control pathways. Methods: A total of 117 participants (ages 7–17 years) were included: 53 in the EF-DD group (33 males; M = 10.4 years), 47 in the STM-DD group (22 males; M = 10.8 years), and 17 typically developing (TD) children (6 males; M = 11.4 years). Diffusion-weighted MRI data were acquired using a multi-shell protocol and preprocessed with QSIPrep. Whole-brain tractography and automated bundle segmentation were performed using MRtrix3 and pyAFQ. Based on a priori hypotheses, analyses focused on left-lateralized dorsal and ventral language pathways, including the arcuate fasciculus/superior longitudinal fasciculus (AF/SLF), inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), and uncinate fasciculus (UF), as well as frontoparietal and cingulo-striatal pathways (bilaterally) implicated in executive control. Fractional anisotropy (FA) was averaged across the central 80% of nodes for each tract. Group differences in FA were assessed using linear models controlling for age, sex, and in-scanner motion. Results: Significant group effects on FA were identified in the left AF and left ILF. In the left AF, the STM-DD group demonstrated lower FA relative to both the EF-DD and TD groups (F(2,111) = 4.61, p = .011), whereas the EF-DD and TD groups did not differ significantly. A similar effect was observed in the left ILF (F(2,111) = 4.22, p = .017), with the STM-DD group showing lower FA compared with the TD group, but not compared with the EF-DD group. Discussion: Cognitive profiles within DD may be differentially associated with structural alterations in canonical language-related white-matter pathways. Children with verbal STM-related difficulties showed lower FA in left-hemisphere tracts implicated in phonological and lexical-orthographic processing, whereas the EF-DD group was not associated with detectable tract-specific FA alterations relative to TD children. Overall, our findings suggest that similar reading difficulties may emerge from dissociable neuroanatomical substrates, helping to uncover the neural bases underlying different DD profiles.
Topic Areas: Reading, Disorders: Developmental