Alexia With and Without Agraphia: An Assessment of Two Classical Syndromes

Claire A. Sheldon, George L. Malcolm, Jason J. S. Barton

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Background: Current cognitive models propose that multiple processes are involved in reading and writing. Objective: Our goal was to use linguistic analyses to clarify the cognitive dysfunction behind two classic alexic syndromes. Methods: We report four experiments oil two patients. one with alexia without agraphia following occipitotemporal lesions, and one with alexia with agraphia from it left angular gyral lesion. Results: The patient with occipital lesions had trouble discriminating real letters from foils and his reading varied with word-length but not with linguistic variables such its part of speech, word frequency or imageability. He read pseudo-words and words with regular spelling better, indicating preserved use of grapheme-to-phoneme pronunciation rules. His writing showed errors that reflected reliance on 'phoneme-to-grapheme' spelling rules. In contrast, the patient with a left angular gyral lesion showed better recognition of letters, words and their meanings. His reading was better for words with high imageability but displayed semantic errors and an inability to use 'grapheme-to-phonem' rules, features consistent with deep dyslexia. His agraphia showed impaired access to both an internal lexicon and 'phoneme-to-grapheme' rules. Conclusion: Some cases of pure alexia may be it perceptual word-form agnosia, with loss of internal representations of letters and words, while the angular gyral syndrome of alexia with agraphia is a linguistic deep dyslexia. The presence or absence of agraphia does not always distinguish between the two; rather, writing can mirror the reading deficits, being more obvious and profound in the case of an angular gyral syndrome.

Original languageEnglish
Pages (from-to)616-624
Number of pages9
JournalCanadian Journal of Neurological Sciences
Volume35
Issue number5
DOIs
Publication statusPublished - Nov 2008

Keywords

  • WORD RECOGNITION
  • DEEP DYSLEXIA
  • PURE ALEXIA
  • ACQUIRED DYSLEXIA
  • RIGHT-HEMISPHERE
  • OBJECT AGNOSIA
  • INFARCTION
  • VARIETIES
  • CONTINUUM
  • MODEL

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