Cognitive and experimental psychology: perception, action, and higher cognitive processes
Cognitive science
Neuropsychology and cognitive psychology
Psycholinguistics
Automatic visual word recognition requires not only well-established phonological
and orthographic representations but also efficient audio-visual integration of these
representations. One possibility is that in developmental dyslexia, inefficient orthographic
processing might underlie poor reading. Alternatively, reading deficit could be due
to inefficient phonological processing or inefficient integration of orthographic
and phonological information. In this event-related potential study, participants
with dyslexia (N = 25) and control readers (N
= 27) were presented with pairs of words and pseudowords in an implicit same-different
task. The reference-target pairs could be identical, or different in the identity
or the position of the letters. To test the orthographic-phonological processing,
target stimuli were presented in visual-only and audiovisual conditions. Participants
with and without dyslexia processed the reference stimuli similarly; however, group
differences emerged in the processing of target stimuli, especially in the audiovisual
condition where control readers showed greater N1 responses for words than for pseudowords,
but readers with dyslexia did not show such difference. Moreover, after 300 ms lexicality
effect exhibited a more focused frontal topographic distribution in readers with dyslexia.
Our results suggest that in developmental dyslexia, phonological processing and audiovisual
processing deficits are more pronounced than orthographic processing deficits.
