DOI: 10.5061/dryad.0p2ngf222
title: Convergent and divergent brain structural and functional abnormalities associated with developmental dyslexia

description: Brain abnormalities in the reading network have been repeatedly reported
 in individuals with developmental dyslexia (DD); however, it is still not
 totally understood where the structural and functional abnormalities are
 consistent/inconsistent across languages. In the current multimodal
 meta-analysis, we found convergent structural and functional alterations
 in the left superior temporal gyrus across languages, suggesting a neural
 signature of DD. We found greater reduction in grey matter volume and
 brain activation in the left inferior frontal gyrus in morpho-syllabic
 languages (e.g. Chinese) than in alphabetic languages, and greater
 reduction in brain activation in the left middle temporal gyrus and
 fusiform gyrus in alphabetic languages than in morpho-syllabic languages.
 These language differences are explained as consequences of being DD while
 learning a specific language. In addition, we also found brain regions
 that showed increased grey matter volume and brain activation, presumably
 suggesting compensations and brain regions that showed inconsistent
 alterations in brain structure and function. Our study provides important
 insights about the etiology of DD from a cross-linguistic perspective with
 considerations of consistency/inconsistency between structural and
 functional alterations.
description: We searched in “PubMed” (http://www.pubmed.org) and “Web of
 science” for neuroimaging studies published from January 1986 to January
 2020 using a combination of a condition term (i.e. dyslexia, reading
 disorder, reading impairment, reading difficulty or reading disability)
 and a technical term (i.e. fMRI, PET, voxel-based morphometry, VBM, or
 neuroimaging), for example, "dyslexia" &
 "fMRI". See the full list of key word combinations in the
 supplementary materials. Additionally, we manually added studies by
 checking the references of the selected papers that were missed in the
 search. The inclusion criteria were: (1) PET, fMRI, voxel-based
 morphometry (VBM) studies or structural studies using a volumetric
 FreeSurfer pipeline, (2) whole-brain results were reported, (3) direct
 group comparisons between readers with DD and age control readers were
 reported, (4) coordinates were reported in Talairach or MNI stereotactic
 space, and (5) studies on DD in the first language. The exclusion criteria
 were (1) studies with only ROI analysis, (2) resting-state studies, (3)
 studies that only included readers with DD or did not report group
 differences, (4) studies with direct group comparisons only between
 readers with DD and reading level control readers, (5) studies on children
 at risk for dyslexia, and (6) studies focused on non-linguistic tasks ).
 Finally, 119 experiments from 110 papers were included in this
 meta-analysis comprising 92 brain functional experiments (from 87 papers)
 and 27 brain structural experiments (from 23 papers). From the original
 publications, we extracted peak coordinates, where there is a significant
 difference between controls and individuals with DD either in brain
 activation or regional GMV. We also extracted effect sizes and other
 information from the publications.
description: Data were processed using Signed Differential Mapping software
 (AES-SDM version 5.14, see http://www.sdmproject.com). Readers can reproduce all the  results using this dataset.  The SDM table information needed for meta-analysis is stored in an Excel file named 'sdm_table'. The detailed information can be found in the original paper (http://dx.doi.org/10.7554/eLife.69523). For the direct comparation, readers should subdive the dataset into a reduced activation dataset and an increased activation dataset.