Visual errors in acquired dyslexia: Evidence for cascaded lexical processing

Author(s): Blanken, G.

Journal/Book: Cognitive Neuropsychol. 1999; 16: 27 Church Rd, Hove BN3 2FA, East Sussex, England. Psychology Press. 631-653.

Abstract: A single case study is reported of the dyslexic and only mildly aphasic patient AT who almost exclusively produced visually related errors in reading aloud. His performance in the auditory modality (auditory comprehension, phoneme discrimination) was nearly perfect, his repetition and oral naming abilities for single-word production were almost unimpaired. Closer examinations of his reading disturbance revealed a deficit in visual processing of orthographic materials which extended to Arabic numbers and other nonlinguistic symbols. Contrasting with this prelexical deficit, AT's performance in reading aloud and also in visual lexical decision was strongly influenced by factor imageability, which could not be attributed to a general semantic deficit. It is argued that AT's pattern of reading performance (prelexical visual impairment and imageability effects on his visual errors) cannot be accounted for by a discrete stage model of lexical-orthographic processing allowing only one lexical candidate to be selected. Rather, the case AT provides empirical evidence for cascaded processing between the lexical and semantic level. The cascade account suggests that not only one but several visually related lexical candidates activate their corresponding semantic representations with different degrees of imageability.

Note: Article Blanken G, Inst German Language, Belfortstr 14, D-79085 Freiburg, GERMANY

Keyword(s): BY-LETTER READER; INTERACTIVE ACTIVATION MODEL; WORD RECOGNITION; ATTENTIONAL DYSLEXIA; PURE ALEXIA; SELECTIVE ATTENTION; SPEECH PRODUCTION; LETTER PERCEPTION; NEGLECT DYSLEXIA; DEEP DYSPHASIA

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