A molecular-genetic and imaging-genetic approach to specific comprehension difficulties in children

Miao Li,Katherine Epstein,Dina Hill,Dongnhu T Truong,Chintan Mehta,Joan Bosson-Heenan,Cheryl Lacadie,Stephanie Gottwald,Mellissa M C Demille,Maureen W Lovett,Erik G Willcutt,Maryanne Wolf,Jeffrey R Gruen,Jan C Frijters,Lisa A Jacobson,E Mark Mahone,Jeffrey G Malins,Richard Boada

doi:10.1038/s41539-018-0034-9

Abstract

Children with poor reading comprehension despite typical word reading skills were examined using neuropsychological, genetic, and neuroimaging data collected from the Genes, Reading and Dyslexia Study of 1432 Hispanic American and African American children. This unexpected poor comprehension was associated with profound deficits in vocabulary, when compared to children with comprehension skills consistent with their word reading. Those with specific comprehension difficulties were also more likely to have RU2Short alleles of READ1 regulatory variants of DCDC2, strongly associated with reading and language difficulties. Subjects with RU2Short alleles showed stronger resting state functional connectivity between the right insula/inferior frontal gyrus and the right supramarginal gyrus, even after controlling for potentially confounding variables including genetic ancestry and socioeconomic status. This multi-disciplinary approach advances the current understanding of specific reading comprehension difficulties, and suggests the need for interventions that are more appropriately tailored to the specific comprehension deficits of this group of children.

Highlights

Between 7 and 15% of school-age children have normal or adequate individual word reading or decoding skills, yet have poor reading comprehension.[1,2,3,4] The Simple View of Reading Model suggests that successful reading comprehension requires both adequate decoding and language comprehension.[5]
First three principal components used as control variables
Socioeconomic status (SES) was coded as a binary variable, and was determined by participation in one or more government assistance programs that have income eligibility requirements (Women, Infants, and Children (WIC); Medicaid/Husky; food stamps; and Section 8 Housing Choice Voucher Program, Section 8)

Summary

Introduction

Between 7 and 15% of school-age children have normal or adequate individual word reading or decoding skills, yet have poor reading comprehension.[1,2,3,4] The Simple View of Reading Model suggests that successful reading comprehension requires both adequate decoding and language comprehension.[5] Even if children have normal decoding skills, they may have poor reading comprehension if they are deficient in language comprehension.[6,7,8] Recent work has shown that students with this condition, known as unexpected poor comprehension, have weak morphological processing and vocabulary skills.[1,2,3,6,8,9,10,11,12] They can have difficulty with higher-level cognition and language skills such as inferences, strategies, working memory, comprehension monitoring, and integration of text information.[13,14,15] Early identification is key for implementing effective intervention prior to significant learning delays, but since they demonstrate adequate individual word reading or decoding, students with unexpected poor comprehension often do not receive special services

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