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Publication
Visual naming deficits in dyslexia: An ERP investigation of different processing domains
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Advisor(s)
Abstract(s)
Naming speed deficits are well documented in developmental dyslexia, expressed by slower naming
times and more errors in response to familiar items. Here we used event-related potentials (ERPs) to
examine at what processing level the deficits in dyslexia emerge during a discrete-naming task. Dyslexic
and skilled adult control readers performed a primed object-naming task, in which the relationship
between the prime and the target was manipulated along perceptual, semantic and phonological dimensions. A 3 2 design that crossed Relationship Type (Visual, Phonemic Onset, and Semantic) with
Relatedness (Related and Unrelated) was used. An attenuated N/P190 – indexing early visual processing –
and N300 – which index late visual processing – was observed to pictures preceded by perceptually
related (vs. unrelated) primes in the control but not in the dyslexic group. These findings suggest suboptimal processing in early stages of object processing in dyslexia, when integration and mapping of
perceptual information to a more form-specific percept in memory take place. On the other hand, both
groups showed an N400 effect associated with semantically related pictures (vs. unrelated), taken to
reflect intact integration of semantic similarities in both dyslexic and control readers. We also found an
electrophysiological effect of phonological priming in the N400 range – that is, an attenuated N400 to
objects preceded by phonemic related primes vs. unrelated – while it showed a more widespread distributed and more pronounced over the right hemisphere in the dyslexics. Topographic differences between groups might have originated from a word form encoding process with different characteristics in
dyslexics compared to control readers.
Description
Keywords
Visual naming Dyslexia ERPs
Pedagogical Context
Citation
Araújo, S., Faísca, L., Reis, A., Marques, J. F., & Petersson, K. M. (2016). Visual naming deficits in dyslexia: An ERP investigation of different processing domains. Neuropsychologia, 91, 61-76. https://doi.org/10.1016/j.neuropsychologia.2016.07.007
Publisher
Elsevier