When mild pure alexia may not be reducible to hemianopic alexia

Cristina Rosazza, Valeria Isella, Ildebrando Appollonio, Tim Shallice

Research output: Contribution to journalComment/debate

Abstract

Individuals with pure alexia often have visual field defects such as right homonymous hemianopia. Relatively few attempts have been made to develop criteria to differentiate pure alexia from hemianopic alexia. In this Commentary we provide concrete suggestions to distinguish the two disorders. We also report on additional assessments with two previously reported cases for whom the diagnosis of pure alexia was called into question and an alternative proposal was offered that the reading deficits were instead due to hemianopia. We show that the results of clinical and neuropsychological tests do not support the account that the reading impairment was caused by the visual field defect. In particular, for both cases, the right homonymous hemianopia was not complete, and a split-field reading task demonstrated an inability also to read words presented in the intact left visual field. In conclusion, pure alexics may indeed show fairly modest word-length effects; however, the presence of right homonymous hemianopia and a non-extreme gradient of reading speed alone are not sufficient grounds to put in doubt the diagnosis. We propose that a fuller clinical and neuropsychological examination taking into account the possible confounding effects of the visual field defects will help to distinguish pure alexia from hemianopic alexia.

Original languageEnglish
Pages (from-to)479-484
Number of pages6
JournalCognitive Neuropsychology
Volume35
Issue number8
DOIs
Publication statusPublished - Nov 17 2018

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Keywords

  • Pure alexia
  • right homonymous hemianopia
  • split-field reading task
  • word-length effect

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Experimental and Cognitive Psychology
  • Developmental and Educational Psychology
  • Arts and Humanities (miscellaneous)
  • Cognitive Neuroscience

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