Putative protective neural mechanisms in prereaders with a family history of dyslexia who subsequently develop typical reading skills

Abstract

Developmental dyslexia affects 40–60% of children with a familial risk (FHD+) compared to a general prevalence of 5–10%. Despite the increased risk, about half of FHD+ children develop typical reading abilities (FHD+Typical). Yet the underlying neural characteristics of favorable reading outcomes in at‐risk children remain unknown. Utilizing a retrospective, longitudinal approach, this study examined whether putative protective neural mechanisms can be observed in FHD+Typical at the prereading stage. Functional and structural brain characteristics were examined in 47 FHD+ prereaders who subsequently developed typical (n = 35) or impaired (n = 12) reading abilities and 34 controls (FHD−Typical). Searchlight‐based multivariate pattern analyses identified distinct activation patterns during phonological processing between FHD+Typical and FHD−Typical in right inferior frontal gyrus (RIFG) and left temporo‐parietal cortex (LTPC) regions. Follow‐up analyses on group‐specific classification patterns demonstrated LTPC hypoactivation in FHD+Typical compared to FHD−Typical, suggesting this neural characteristic as an FHD+ phenotype. In contrast, RIFG showed hyperactivation in FHD+Typical than FHD−Typical, and its activation pattern was positively correlated with subsequent reading abilities in FHD+ but not controls (FHD−Typical). RIFG hyperactivation in FHD+Typical was further associated with increased interhemispheric functional and structural connectivity. These results suggest that some protective neural mechanisms are already established in FHD+Typical prereaders supporting their typical reading development.

Multifactorial pathways facilitate resilience among kindergarteners at risk for dyslexia: A longitudinal behavioral and neuroimaging study

“…The closest related longitudinal study starting at the pre-reading stage observed that temporoparietal segments of the right SLF showed a higher rate of development (i.e., increasing FA) over the course of learning to read among children with familial risk for dyslexia who subsequently became typical readers relative to those who became poor readers (Wang et al, 2016). Building on this evidence, the present study is the first to identify that FA in the posterior (tem- during phonological processing (Yu et al, 2020), which suggests that these characteristic left-hemispheric alterations may be more closely linked to genetic susceptibility for dyslexia rather than 'poor' reading outcomes in general. Taken together, recognizing sampling differences, the convergence of findings in the right SLF from independent samples with differing approaches points toward a putative protective neural factor that may facilitate subsequent reading outcomes for at-risk children.…”

“…Note that while predominantly left‐hemispheric alterations have been repeatedly associated with poor reading/dyslexia (e.g., Vandermosten et al., 2012; Vandermosten et al., 2013), the present sample did not reflect group differences in left‐hemispheric pathways at the kindergarten age among subsequently typical versus poor readers. By contrast, children with familial risk for dyslexia who subsequently demonstrate typical reading outcomes still demonstrate left‐hemispheric functional hypoactivation during phonological processing (Yu et al., 2020), which suggests that these characteristic left‐hemispheric alterations may be more closely linked to genetic susceptibility for dyslexia rather than ‘poor’ reading outcomes in general. Taken together, recognizing sampling differences, the convergence of findings in the right SLF from independent samples with differing approaches points toward a putative protective neural factor that may facilitate subsequent reading outcomes for at‐risk children.…”

Brain dynamics of (a)typical reading development—a review of longitudinal studies

“…Since this pattern was present only in children with dyslexia, but not in controls, it was interpreted as a brain mechanism altered and specific for dyslexia rather than reflecting growth in reading ability in general 73 . Right IFG hyperactivity during a phonological task at the pre-reading stage was present only in those children at risk of dyslexia who developed typical reading skills, but not in children developing dyslexia, which suggests a protective mechanism 74 .…”

Distinctive neural correlates of phonological processing and reading impairment in fetal alcohol-exposed adolescents with and without facial dysmorphology

“…A first sound matching (FSM) task was presented in a block design to examine the neural mechanisms underlying phonological processing (Raschle et al, 2012, 2013; Yu et al, 2018, 2020). During each trial, the participant saw two pictures of two common objects presented on the left and right side of the screen for 2 seconds each, accompanied by the objects’ names spoken by either a male or a female.…”