Disruption of Functional Brain Networks Underlies the Handwriting Deficit in Children With Developmental Dyslexia

Abstract

Developmental dyslexia (DD) is a neurological-based learning disorder that affects 5-17.5% of children. Handwriting difficulty is a prevailing symptom of dyslexia, but its neural mechanisms remain elusive. Using functional magnetic resonance imaging (fMRI), this study examined functional brain networks associated with handwriting in a copying task in Chinese children with DD (n = 17) and age-matched children (n = 36). We found that dyslexics showed reduced network connectivity between the sensory-motor network (SMN) and the visual network (VN), and between the default mode network (DMN) and the ventral attention network (VAN) during handwriting, but not during drawing geometric figures. Moreover, the connectivity strength of the networks showing group differences was correlated with handwriting speed, reading and working memory, suggesting that the handwriting deficit in DD is linked with disruption of a large-scale brain network supporting motoric, linguistic and executive control processes. Taken together, this study demonstrates the alternations of functional brain networks that underly the handwriting deficit in Chinese dyslexia, providing a new clue for the neural basis of DD.

Phoneme Representation and Articulatory Impairment: Insights from Adults with Comorbid Motor Coordination Disorder and Dyslexia

“…As we have already pointed out [49], sensorimotor deficits in dyslexia can include postural, oculomotor, motor coordination, and implicit motor learning disorders in dyslexic children and adults [27,34,50,51]. More recent research on dyslexia ( [52], for a recent review), and on motor comorbidities, have, for example, addressed dysfunctions in writing abilities [53,54] and even rhythmic motor competencies [55]. Nevertheless, there is still a consensus that motor difficulties are present in part of the dyslexia population, albeit to a larger extent in children than adults [27,34].…”

Exploring the effectiveness of a novel memory training program for students with learning disabilities in the United Arab Emirates: investigating the role of gender differences

“…Recent research on learning disabilities and memory has focused on a range of topics, including the neurobiological basis of these conditions, the impact of technology on memory and learning, and potential interventions. In a study that was carried out by Liu et al (2022) study on changes in functional connectivity in children with dyslexia during visual and phonological processing tasks, functional magnetic resonance imaging (fMRI) was utilized to investigate the neural networks that are involved in the processing of visual and phonological information in children who have dyslexia. The authors found that children with dyslexia showed altered functional connectivity in brain regions associated with phonological processing, suggesting that dyslexia may be related to abnormal neural connectivity.…”

Abnormal brain activation patterns during speech perception and production in children and adults with reading disability

“…Nonetheless, RD readers could not efficiently deactivate the default mode network for the more challenging foreign speech imitation to a greater degree. The default mode network has been found to play an important role in learning (Howard-Jones, Jay, Mason, & Jones, 2016;Lin et al, 2017), and its abnormality has been reported in developmental disorders, such as RD (Boros et al, 2016;Liu, Li, Bi, Xu, & Yang, 2022;Mateu-Estivill et al, 2021), ASD (Assaf et al, 2010;Murdaugh et al, 2012;Washington et al, 2014), and ADHD (Castellanos & Proal, 2012;Qiu et al, 2011;Uddin et al, 2008). In a recent study, the default mode network showed the largest developmental changes in brain signal complexity during the period of 6-13 years of age, compared to 5 other networks, namely, vision, motor, dorsal attention, ventral attention and frontal-parietal network (Jia et al, 2023), suggesting that the development of the default mode network might be more influenced by learning experiences and environment than the other networks.…”