Speed of lower-level auditory and visual processing as a basic factor in dyslexia: Electrophysiological evidence

Zvia Breznitz, Ann Meyler

    Research output: Contribution to journalArticlepeer-review

    Abstract

    This study investigated speed of processing (SOP) among college-level adult dyslexic and normal readers in nonlinguistic and sublexical linguistic auditory and visual oddball tasks, and a nonlinguistic cross-modal choice reaction task. Behavioral and electrophysiological (ERP) measures were obtained. The results revealed that between both groups, reaction times (RT) were longer and the latencies of P2 and P3 components occurred later in the visual as compared to auditory oddball tasks. RT and ERP latencies were longest in the cross-modal task. RT and ERP latencies were delayed among dyslexic as compared to normal readers across tasks. On the oddball tasks, group differences in brain activity were observed only when responding to low-probability targets. These differences were largest for the P3 component, and most pronounced in the case of phonemes. The gap between ERP latencies in the visual versus the auditory modalities for each component was larger among dyslexic as compared to normal readers, and was particularly evident at the linguistic level. A hypothesis is proposed that suggests an amodal, basic SOP deficit among dyslexic readers. The slower cross-modal SOP is attributed to slower information processing in general and to disproportionate "asynchrony" between SOP in the visual versus the auditory system. It is suggested that excessive asynchrony in the SOP of the two systems may be one of the underlying causes of dyslexics' impaired reading skills.

    Original languageEnglish
    Pages (from-to)166-184
    Number of pages19
    JournalBrain and Language
    Volume85
    Issue number2
    DOIs
    StatePublished - May 2003

    Bibliographical note

    Funding Information:
    This study was supported by a research grant from the Ministry of Education, Israel.

    Keywords

    • Adults
    • Auditor
    • Cross-modal
    • Dyslexia
    • ERP
    • Electrophysiology
    • Linguistic
    • Low-level processing
    • Nonlinguistic
    • P2
    • P3
    • Reading
    • Speed of processing
    • Visual

    ASJC Scopus subject areas

    • Experimental and Cognitive Psychology
    • Speech and Hearing
    • Cognitive Neuroscience
    • Language and Linguistics
    • Linguistics and Language

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