Atypical neural synchronization to speech envelope modulations in dyslexia.
A fundamental deficit in the synchronization of neural oscillations to temporal information in speech could underlie phonological processing problems in dyslexia. In this study, the hypothesis of a neural synchronization impairment is investigated more specifically as a function of different neural oscillatory bands and temporal information rates in speech. Auditory steady-state responses to 4, 10, 20 and 40Hz modulations were recorded in normal reading and dyslexic adolescents to measure neural synchronization of theta, alpha, beta and low-gamma oscillations to syllabic and phonemic rate information. In comparison to normal readers, dyslexic readers showed reduced non-synchronized theta activity, reduced synchronized alpha activity and enhanced synchronized beta activity. Positive correlations between alpha synchronization and phonological skills were found in normal readers, but were absent in dyslexic readers. In contrast, dyslexic readers exhibited positive correlations between beta synchronization and phonological skills. Together, these results suggest that auditory neural synchronization of alpha and beta oscillations is atypical in dyslexia, indicating deviant neural processing of both syllabic and phonemic rate information. Impaired synchronization of alpha oscillations in particular demonstrated to be the most prominent neural anomaly possibly hampering speech and phonological processing in dyslexic readers.
Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Herestraat 49 Box 721, 3000 Leuven, Belgium; Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leopold Vanderkelenstraat 32 Box 3765, 3000 Leuven, Belgium. Electronic address: astrid.devos@kuleuven.be.
Astrid
A
De Vos
Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Herestraat 49 Box 721, 3000 Leuven, Belgium; Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leopold Vanderkelenstraat 32 Box 3765, 3000 Leuven, Belgium.
Sophie
S
Vanvooren
Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Herestraat 49 Box 721, 3000 Leuven, Belgium; Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leopold Vanderkelenstraat 32 Box 3765, 3000 Leuven, Belgium.
Jolijn
J
Vanderauwera
Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leopold Vanderkelenstraat 32 Box 3765, 3000 Leuven, Belgium.
Pol
P
Ghesquière
Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Herestraat 49 Box 721, 3000 Leuven, Belgium.
Jan
J
Wouters
D000293:Adolescent; D000513:Alpha Rhythm; D001303:Auditory Cortex / Q000503:physiopathology; D001611:Beta Rhythm; D058256:Brain Waves / Q000502:physiology*; D004410:Dyslexia / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D011932:Reading; D013060:Speech
Auditory steady-state response; Cortical synchronization; Dyslexia; EEG; Neural oscillations; Speech envelope