Understanding reduced language lateralization in children with dyslexia
Year: 2026
Type: preprint
Abstract: Developmental dyslexia is characterized by difficulties with accurate and fluent word recognition, spelling, and decoding, often linked to deficits in the phonological component of language (International Dyslexia Association, 2025; Vellutino et al., 2004; Snowling, 2000). Atypical hemispheric specialization has long been proposed as one account of dyslexia, with early theories linking reading difficulty to reduced left-hemisphere dominance (Orton, 1925; Annett, 1985), and neuroimaging studies support this conclusion, showing functional differences in how typical readers versus dyslexic readers engage left-hemisphere language regions (Li & Bi, 2022; Maisog et al., 2008; Richlan et al., 2009, 2011). However, these studies rarely compare lateralization and cross-task stability of language network activation across tasks. More recent frameworks suggest lateralization is not a global phenomenon but rather task-specific, suggesting that language difficulty in dyslexia may arise from inefficient and diffuse neural organization compared to typical development of focal language regions (Verhelst et al., 2025; Bishop, 2013). We previously tested functional organization of the language network across auditory language comprehension versus visual word tasks in a small sample of 52 7-10 year olds, and found that differences between dyslexic versus typical groups in the extent of language network lateralization was task-dependent. To test the robustness of this effect, we will replicate analyses in a larger sample of 231 7-13 year olds (107 typical, 124 dyslexic). This dataset includes functional MRI acquired during a range of language tasks that vary by modality (listening versus reading) and task demands (active versus passive), including both the paradigms used in the original study and new task paradigms. Following the analysis steps of the previous study, we will use precision fMRI to establish individual-specific language ROIs and determine the extent of activation and lateralization in that network during each task (Fedorenko et al., 2010). The differences in lateralization between tasks and cross-task stability will help to answer the question of whether dyslexia is associated with a global atypical lateralization or reduced cross-task lateralization stability.
Institution: Massachusetts Institute of Technology
Language: English
Subfield: Developmental and Educational Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W7203857616