title: Enhancement of brain event-related potentials to speech sounds is associated with compensated reading skills in dyslexic children with familial risk for dyslexia.
abstract: Specific reading disability, dyslexia, is a prevalent and heritable disorder impairing reading acquisition characterized by a phonological deficit. However, the underlying mechanism of how the impaired phonological processing mediates resulting dyslexia or reading disabilities remains still unclear. Using ERPs we studied speech sound processing of 30 dyslexic children with familial risk for dyslexia, 51 typically reading children with familial risk for dyslexia, and 58 typically reading control children. We found enhanced brain responses to shortening of a phonemic length in pseudo-words (/at:a/ vs. /ata/) in dyslexic children with familial risk as compared to other groups. The enhanced brain responses were associated with better performance in behavioral phonemic length discrimination task, as well as with better reading and writing accuracy. Source analyses revealed that the brain responses of sub-group of dyslexic children with largest responses originated from a more posterior area of the right temporal cortex as compared to the responses of the other participants. This is the first electrophysiological evidence for a possible compensatory speech perception mechanism in dyslexia. The best readers within the dyslexic group have probably developed alternative strategies which employ compensatory mechanisms substituting their possible earlier deficit in phonological processing and might therefore be able to perform better in phonemic length discrimination and reading and writing accuracy tasks. However, we speculate that for reading fluency compensatory mechanisms are not that easily built and dyslexic children remain slow readers during their adult life.
authors.affiliation: Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland. Electronic address: kaisa.lohvansuu@jyu.fi.
authors.forename: Kaisa
authors.initials: K
authors.lastname: Lohvansuu
authors.affiliation: Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Jarmo A
authors.initials: JA
authors.lastname: Hämäläinen
authors.affiliation: Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Annika
authors.initials: A
authors.lastname: Tanskanen
authors.affiliation: Logopedics and Child Language Research Centre, Faculty of Humanities, University of Oulu, P.O. Box 1000, FI-90014 University of Oulu, Finland; Department of Clinical Neurophysiology, Neurocognitive Unit, Oulu University Hospital, P.O. Box 50, FI-90029 Oulu University Hospital, Finland.
authors.forename: Leena
authors.initials: L
authors.lastname: Ervast
authors.affiliation: Logopedics and Child Language Research Centre, Faculty of Humanities, University of Oulu, P.O. Box 1000, FI-90014 University of Oulu, Finland; Department of Clinical Neurophysiology, Neurocognitive Unit, Oulu University Hospital, P.O. Box 50, FI-90029 Oulu University Hospital, Finland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Heikkinen
authors.affiliation: Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Lyytinen
authors.affiliation: Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Paavo H T
authors.initials: PH
authors.lastname: Leppänen
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D002648:Child; D004410:Dyslexia / Q000175:diagnosis / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011932:Reading; D012307:Risk Factors; D013067:Speech Perception / Q000502:physiology*
keywords: Compensation; Dyslexia; EEG; ERP; Phonemic length discrimination; Speech perception