White matter properties differ in 6-year old Readers and Pre-readers

Abstract

Reading, an essential life skill in modern society, is typically learned during childhood. Adults who can read show white matter differences compared to adults who never learned to read. Studies have not established whether children who can read show similar white matter differences compared to children who cannot read. We compared 6-year old children who could decode written English words and pseudowords (n=31; Readers) and 6-year old children who could not decode pseudowords and had a standard score < 100 on a task for reading single words (n=11; Pre-Readers). We employed diffusion MRI and tractography to extract fractional anisotropy (FA) along the trajectory of 6 bilateral intra-hemispheric tracts and 2 posterior subdivisions of the corpus callosum. Readers demonstrated significantly increased FA within the left anterior segment of the superior longitudinal fasciculus (aSLF-L) and the right uncinate fasciculus (UF-R) compared to Pre-Readers. FA in the aSLF-L was significantly correlated with phonological awareness; FA in the UF-R was significantly correlated with language. Correlations in the UF-R but not the aSLF-L remained significant after controlling for reading ability, revealing that UF-R group differences were related to both children's language and reading abilities. Taken together, these findings demonstrate new evidence showing that individual differences in white matter structure relate to whether children have begun to read.

White matter properties associated with pre‐reading skills in 6‐year‐old children born preterm and at term

“…However, a recent study found that the direction of these associations varied between the two birth groups, suggesting a differing neurobiology for reading in children and adolsecents born preterm and at term . We recently demonstrated in the current sample of 6‐year‐old children born at term that fractional anisotropy of the left arcuate fasciculus (AF‐L) and left superior longitudinal fasciculus (SLF‐L) was associated with phonological awareness skills . In addition, we found that fractional anisotropy of the right uncinate fasciculus (UF‐R) and SLF‐L was associated with receptive and expressive language skills .…”

“…Understanding the neurobiological basis of early pre‐reading abilities in both children born preterm and at term may provide insight into the process of learning to read. Studies to date have primarily examined how early pre‐reading skills relate to neurobiological properties, such as metrics of white matter pathways, in children born at term but not in children born preterm at the early stages of learning to read …”

“…We recently demonstrated in the current sample of 6‐year‐old children born at term that fractional anisotropy of the left arcuate fasciculus (AF‐L) and left superior longitudinal fasciculus (SLF‐L) was associated with phonological awareness skills . In addition, we found that fractional anisotropy of the right uncinate fasciculus (UF‐R) and SLF‐L was associated with receptive and expressive language skills . To our knowledge, no study to date has examined whether children born preterm versus their peers born at term demonstrate similar or different patterns of associations between fractional anisotropy of white matter tracts and pre‐reading skills at the age at which children are learning to read.…”

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

“…Further evidence supports the dual‐route hypothesis that dorsal and ventral reading‐related tracts are functionally related to different reading strategies (e.g., sublexical and lexical). As part of the dorsal route for phonology‐based reading, the left AF and SLF were associated with performance on phonological awareness (PA) tasks (Saygin et al, ; Travis, Adams, Kovachy, Ben‐Shachar, & Feldman, ; Vandermosten et al, ; Yeatman et al, ). As part of the ventral route for lexical reading strategies, the left IFOF was related to orthographic processing (Gebauer, Fink, Filippini, et al, ; Vandermosten, Boets, Poelmans, et al, ).…”

The relationship between socioeconomic status and white matter microstructure in pre‐reading children: A longitudinal investigation

“…The efficient integration across these spatially disparate brain regions is made possible by long‐range white matter connections that form across development (Wandell, Rauschecker, & Yeatman, ). Three white matter tracts in particular have a documented association with reading and reading‐related skills in adults and children as early as preschool (1) arcuate fasciculus (AF), connecting the superior temporal lobe with the inferior frontal gyrus (IFG); (2) superior longitudinal fasciculus (SLF), connecting the inferior parietal with the inferior frontal/premotor regions; and (3) inferior longitudinal fasciculus (ILF), connecting the posterior inferior temporal gyrus with the ventral anterior and medial temporal lobe (Deutsch et al, ; Frye et al, ; Klingberg et al, ; Lebel & Beaulieu, ; Myers et al, ; Niogi & McCandliss, ; Travis, Adams, Kovachy, Ben‐Shachar, & Feldman, ; Yeatman, Dougherty, Ben‐Shachar, & Wandell, ; Yeatman et al, ; Saygin et al, ; Vandermosten, Boets, Wouters, & Ghesquiere, ; Wang et al, ; Zhao, de Schotten, Altarelli, Dubois, & Ramus, ; Supporting Information Figure S1). The left ILF passes in close proximity to the visual word form area (Yeatman, Rauschecker, & Wandell, ), a cortical region that becomes left‐lateralized and specialized for word recognition through experience (Cohen et al, ; Dehaene & Cohen, ).…”