White matter alterations and tract lateralization in children with dyslexia and isolated spelling deficits

Abstract

The present study investigated whether children with a typical dyslexia profile and children with isolated spelling deficits show a distinct pattern of white matter alteration compared with typically developing peers. Relevant studies on the topic are scarce, rely on small samples, and often suffer from the limitations of conventional tensor‐based methods. The present Constrained Spherical Deconvolution study includes 27 children with typical reading and spelling skills, 21 children with dyslexia and 21 children with isolated spelling deficits. Group differences along major white matter tracts were quantified utilizing the Automated Fiber Quantification software and a lateralization index was calculated in order to investigate the structural asymmetry of the tracts. The two deficit groups mostly displayed different patterns of white matter alterations, located in the bilateral inferior longitudinal fasciculi, right superior longitudinal fasciculus, and cingulum for the group with dyslexia and in the left arcuate fasciculus for the group with isolated spelling deficits. The two deficit groups differed also with respect to structural asymmetry. Children with dyslexia did not show the typical leftward asymmetry of the arcuate fasciculus, whereas the group with isolated spelling deficits showed absent rightward asymmetry of the inferior fronto‐occipital fasciculus. This study adds evidence to the notion that different profiles of combined or isolated reading and spelling deficits are associated with different neural signatures.

A general role for ventral white matter pathways in morphological processing: going beyond reading

“…For example, participants could use orthographic strategies and visual imagery while searching for morphologically-related words. In this case, the effects observed in the ventral tracts may reflect their well-known involvement in orthographic processing (Banfi et al, 2019;Horowitz-Kraus et al, 2014;Huber et al, 2018;Ozernov-Palchik et al, 2019;Vandermosten et al, 2012;Yeatman et al, 2012a). Although the current data do no not allow to preclude this alternative explanation of the results, it seems less plausible given that morpheme-based fluency was not correlated with reading ability.…”

Microstructural disruption of the right inferior fronto‐occipital and inferior longitudinal fasciculus contributes to WMH‐related cognitive impairment

“…Family‐wise error (FWE) correction was applied to the 1600 points (16 fibers × 100 points) and a corrected significant level at 0.05 . Then, within each fiber, only more than or equal to three adjacent nodes were reported . To assess the associations between WM integrity and cognitive performance, partial correlation was performed using SPSS while controlling for age, years of education, and gender.…”

Aberrant White Matter Microstructure as a Potential Diagnostic Marker in Alzheimer's Disease by Automated Fiber Quantification

“…Age, gender and years of education were included as confounding covariates in the general linear model (GLM). The false discovery rate (FDR) correction was used to determine the significance for p -values ( p < 0.05) and only ≥ 3 adjacent nodes were reported (Banfi et al, 2019 ). To explore the relationship between white matter microstructural integrity and cognition, partial correlation analyses were performed by SPSS while controlling for age, gender, and years of education.…”