White Matter Patterns Related to Reading and Executive Function Deficits in Children with Developmental Dyslexia: A Diffusion Tensor Imaging Study

Developmental Dyslexia (DD) is characterized by reading difficulties associated also with executive functions (EF) challenges. These readers showed altered brain activation in the left hemisphere and often demonstrate right hemisphere activation as a compensation strategy. Despite studies demonstrating alterations in structural connectivity associated with reading challenges in children with DD, anatomical changes related to the EF difficulties in children with DD are scarce.
Diffusion tensor imaging, reading and EF data were acquired in children with typical reading (TRs) and DD. After assessing reading and EF abilities, clusters with significant difference between children with DD and TRs in fractional anisotropy (FA) values in tracts related to reading were defined using an Automatic Fiber Quantification algorithm.
Children with DD showed significantly decreased reading and EF abilities compared to TRs. Higher FA in left lateralized tracts in left temporal, right frontal and right ventral regions were found in TRs. Increased FA in left occipito-temporal, right parietal and dorsal temporal regions were found in children with DD. Children with DD had positive correlation of reading and EF with FA in left temporo-parietal tracts while TRs had negative correlation of EF with FA in right temporo-parietal tracts. Both groups shared negative correlations between EFs and right frontal clusters.
Our findings provide structural support for right hemisphere compensation in children with DD. They suggest greater diffusivity in the left hemisphere in children with DD may predict stronger reading and EF skill, and provide evidence of differential utilization of right frontal white-matter relatedness to their EF dysfunctions.