title: Neuroanatomical precursors of dyslexia identified from pre-reading through to age 11.
abstract: Developmental dyslexia is a common reading disorder that negatively impacts an individual's ability to achieve literacy. Although the brain network involved in reading and its dysfunction in dyslexia has been well studied, it is unknown whether dyslexia is caused by structural abnormalities in the reading network itself or in the lower-level networks that provide input to the reading network. In this study, we acquired structural magnetic resonance imaging scans longitudinally from 27 Norwegian children from before formal literacy training began until after dyslexia was diagnosed. Thus, we were able to determine that the primary neuroanatomical abnormalities that precede dyslexia are not in the reading network itself, but rather in lower-level areas responsible for auditory and visual processing and core executive functions. Abnormalities in the reading network itself were only observed at age 11, after children had learned how to read. The findings suggest that abnormalities in the reading network are the consequence of having different reading experiences, rather than dyslexia per se, whereas the neuroanatomical precursors are predominantly in primary sensory cortices.
authors.affiliation: 1 Laboratory of Neuro Imaging and Institute for Neuroimaging and Informatics, Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90032, USA kristi.clark@ini.usc.edu.
authors.forename: Kristi A
authors.initials: KA
authors.lastname: Clark
authors.affiliation: 2 Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway 3 Department of Education, UiT the Arctic University of Norway, 9019 Tromsø, Norway.
authors.forename: Turid
authors.initials: T
authors.lastname: Helland
authors.affiliation: 2 Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway 4 Department of Medical Engineering, Haukeland University Hospital, 5021 Bergen, Norway.
authors.forename: Karsten
authors.initials: K
authors.lastname: Specht
authors.affiliation: 5 Department of Neurology, Geffen School of Medicine at the University of California, Los Angeles, CA 90095, USA 6 Department of Psychiatry and Biobehavioural Sciences, Geffen School of Medicine at the University of California, Los Angeles, CA 90095, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Narr
authors.affiliation: 7 Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Manis
authors.affiliation: 1 Laboratory of Neuro Imaging and Institute for Neuroimaging and Informatics, Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90032, USA.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.affiliation: 2 Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway 8 Division of Psychiatry, Haukeland University Hospital, 5021 Bergen, Norway 9 Department of Radiology, Haukeland University Hospital, 5021 Bergen, Norway.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hugdahl
mesh_terms: D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D004410:Dyslexia / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D011932:Reading
keywords: cortical thickness; development; neuroimaging; paediatric; reading