Hanne Poelmans|Heleen Luts|Maaike Vandermosten|Bart Boets|Pol Ghesquière|Johan Wouters
Auditory Steady State Cortical Responses Indicate Deviant Phonemic-Rate Processing in Adults With Dyslexia
KU Leuven|KU Leuven|KU Leuven|KU Leuven|KU Leuven|KU Leuven
speech intelligibility strongly influenced ability process temporal modulations hypothesized dyslexia deficient processing rapidly changing auditory information underlies deficient development phonological representations causing reading spelling problems lowfrequency modulations 4 20 hz correspond processing rate important phonological segments syllables phonemes respectively speech therefore provide bridge lowlevel auditory phonological processing present study temporal modulation processing investigated auditory steady state responses assrs normalreading dyslexic adultsmultichannel assrs recorded normalreading dyslexic adults response speechweighted noise stimuli amplitude modulated 80 20 4 hz 80 hz modulation known primarily generated brainstem whereas 20 4 hz modulations mainly generated cortex furthermore 20 4 hz modulations provide objective auditory performance measure related phonemic syllabicrate processing addition neurophysiological measures psychophysical tests speechinnoise perception phonological awareness assessedon basis response strength phase coherence measures normalreading dyslexic participants showed similar processing brainstem level cortical level auditory system dyslexic subjects demonstrated deviant phonemicrate responses compared normal readers whereas group differences found syllabic rate furthermore relationship phonemicrate assrs psychophysical tests speechinnoise perception phonological awareness obtainedthe results suggest reduced cortical processing phonemicrate modulations dyslexic adults presumably resulting limited integration temporal information dorsal phonological pathway