Facial speech gestures: the relation between visual speech processing, phonological awareness, and developmental dyslexia in 10‐year‐olds
Published online on October 21, 2015
Abstract
Successful communication in everyday life crucially involves the processing of auditory and visual components of speech. Viewing our interlocutor and processing visual components of speech facilitates speech processing by triggering auditory processing. Auditory phoneme processing, analyzed by event‐related brain potentials (ERP), has been shown to be associated with impairments in reading and spelling (i.e. developmental dyslexia), but visual aspects of phoneme processing have not been investigated in individuals with such deficits. The present study analyzed the passive visual Mismatch Response (vMMR) in school children with and without developmental dyslexia in response to video‐recorded mouth movements pronouncing syllables silently. Our results reveal that both groups of children showed processing of visual speech stimuli, but with different scalp distribution. Children without developmental dyslexia showed a vMMR with typical posterior distribution. In contrast, children with developmental dyslexia showed a vMMR with anterior distribution, which was even more pronounced in children with severe phonological deficits and very low spelling abilities. As anterior scalp distributions are typically reported for auditory speech processing, the anterior vMMR of children with developmental dyslexia might suggest an attempt to anticipate potentially upcoming auditory speech information in order to support phonological processing, which has been shown to be deficient in children with developmental dyslexia.
Studies demonstrated impaired auditory speech processing in individuals with developmental dyslexia (DD), but visual aspects of speech processing have hardly been investigated. We analyzed the visual Mismatch Response (vMMR) to mouth movements silently pronouncing syllables in school children with and without DD. Children without DD show a posterior vMMR, whereas children with DD show an anterior vMMR, which was more pronounced in children with severe phonological deficits. As anterior MMR scalp distributions are typically observed for auditory speech processing, the anterior vMMR of children with DD might suggest an attempt to anticipate potentially upcoming auditory speech information in order to support phonological processing.