Altered patterns of directed connectivity within the reading network of dyslexic children and their relation to reading dysfluency. (February 2017)

• Record Type: Journal Article
• Authors: Žarić, Gojko; Correia, João M.; Fraga González, Gorka; Tijms, Jurgen; van der Molen, Maurtis W.; Blomert, Leo; Bonte, Milene
• Is Part Of: Developmental cognitive neuroscience. Volume 23(2017)
• Page Start: 1
• Page End: 13
• Publication Date: 2017-02
• Subjects: DTF directed transfer function -- TR typical readers -- MDD moderately dysfluent dyslexic readers -- SDD severely dysfluent dyslexic readers; Developmental dyslexia -- Reading fluency -- Visual word recognition -- Directed functional connectivity -- Directed transfer function; Cognitive neuroscience -- Periodicals; Developmental neurobiology -- Periodicals; Neuropsychology -- Periodicals; Neuropsychiatry -- Periodicals; 612.8233
• DOI: 10.1016/j.dcn.2016.11.003
• Languages: English
• ISSNs: 1878-9293

Abstract

Graphical abstract: Highlights: Directed (EEG) connectivity shows altered visual word processing in dyslexic children. Dyslexic children show reduced posterior-to-anterior connectivity. Severely dysfluent dyslexic children show enhanced anterior-to-posterior connectivity. Patterns of connectivity scale with the severity of reading (dys)fluency. Abstract: Reading is a complex cognitive skill subserved by a distributed network of visual and language-related regions. Disruptions of connectivity within this network have been associated with developmental dyslexia but their relation to individual differences in the severity of reading problems remains unclear. Here we investigate whether dysfunctional connectivity scales with the level of reading dysfluency by examining EEG recordings during visual word and false font processing in 9-year-old typically reading children (TR) and two groups of dyslexic children: severely dysfluent (SDD) and moderately dysfluent (MDD) dyslexics. Results indicated weaker occipital to inferior-temporal connectivity for words in both dyslexic groups relative to TRs. Furthermore, SDDs exhibited stronger connectivity from left central to right inferior-temporal and occipital sites for words relative to TRs, and for false fonts relative to both MDDs and TRs. Importantly, reading fluency was positively related with forward and negatively with backward connectivity. Our results suggest disrupted visual processing of words in both dyslexic groups, together with a compensatory recruitment of right posterior brain regions especially in the SDDs during word and false font processing. Functional connectivity in the brain's reading network may thus depend on the level of reading dysfluency beyond group differences between dyslexic and typical readers.