[TS-4.3] Facial speech gestures: The relation between visual speech processing and dyslexia in 10-year-olds

Schaadt, G. 1, 2 , Männel, C. 1 , Pannekamp, A. 2 , Oberecker, R. 1 , van der Meer, E. 2 & Friederici, A. 1

1 Max Planck Institute for Human Cognitive and Brain Sciences
2 Humboldt-University of Berlin; Department of Psychology

Successful communication in everyday life crucially involves auditory and visual components of speech. Viewing our interlocutor facilitates speech perception by triggering auditory processing, even before the auditory input is fully received. The causal role of auditory speech perception in developmental dyslexia has been widely discussed, revealing deficits in phoneme discrimination. However, visual aspects of phoneme perception have not been investigated in dyslexics. The present study addresses this issue in school children with and without writing problems, using a passive visual oddball paradigm with facial speech gestures silently producing the phonemes /pa/ and /ga/. Our results reveal that normally developing children discriminate these facial gestures, showing a positivity with an occipital distribution in response to the infrequent gestures in the experiment. Interestingly, children with writing problems also show a positivity as discrimination response, however, with an anterior distribution. These results indicate qualitative processing differences between children with writing problems and their normally developing peers for visual features of phoneme perception. The different distributions of discrimination responses across groups suggest that children without writing problems recruit occipital regions typically involved in visual processing. In contrast, children with writing problems seem to rely on anterior regions, possibly engaging fine-grained articulatory or subvocal processes as compensatory processes. Further investigations need to show whether such compensatory mechanisms support the insufficient auditory speech-related phonological representations in individuals with developmental dyslexia.