Adult dyslexic readers benefit less from visual input during audiovisual speech processing: fMRI evidence
Publication year
2018Number of pages
18 p.
Source
Neuropsychologia, 117, (2018), pp. 454-471ISSN
Publication type
Article / Letter to editor
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Organization
PI Group Neurobiology of Language
SW OZ DCC PL
SW OZ BSI OLO
Journal title
Neuropsychologia
Volume
vol. 117
Languages used
English (eng)
Page start
p. 454
Page end
p. 471
Subject
110 000 Neurocognition of Language; DI-BCB_DCC_Theme 1: Language and Communication; Learning and Plasticity; PsycholinguisticsAbstract
The aim of the present fMRI study was to investigate whether typical and dyslexic adult readers differed in the neural correlates of audiovisual speech processing. We tested for Blood Oxygen-Level Dependent (BOLD) activity differences between these two groups in a 1-back task, as they processed written (word, illegal consonant strings) and spoken (auditory, visual and audiovisual) stimuli. When processing written stimuli, dyslexic readers showed reduced activity in the supramarginal gyrus, a region suggested to play an important role in phonological processing, but only when they processed strings of consonants, not when they read words. During the speech perception tasks, dyslexic readers were only slower than typical readers in their behavioral responses in the visual speech condition. Additionally, dyslexic readers presented reduced neural activation in the auditory, the visual, and the audiovisual speech conditions. The groups also differed in terms of superadditivity, with dyslexic readers showing decreased neural activation in the regions of interest. An additional analysis focusing on vision-related processing during the audiovisual condition showed diminished activation for the dyslexic readers in a fusiform gyrus cluster. Our results thus suggest that there are differences in audiovisual speech processing between dyslexic and normal readers. These differences might be explained by difficulties in processing the unisensory components of audiovisual speech, more specifically, dyslexic readers may benefit less from visual information during audiovisual speech processing than typical readers. Given that visual speech processing supports the development of phonological skills fundamental in reading, differences in processing of visual speech could contribute to differences in reading ability between typical and dyslexic readers.
This item appears in the following Collection(s)
- Academic publications [242594]
- Donders Centre for Cognitive Neuroimaging [3959]
- Electronic publications [129556]
- Faculty of Social Sciences [29964]
- Open Access publications [104168]
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