Alexia due to ischemic stroke of the visual word form area

Abstract

The visual word form area (VWFA) is a region in the posterior left occipitotemporal cortex adjacent to the fusiform gyrus hypothesized to mediate word recognition. Evidence supporting the role of this area in reading comes from neuroimaging studies of normal subjects, case-controlled lesion studies, and studies of patients with surgical resection of the VWFA for tumors or epilepsy. Based on these prior reports, a small discrete lesion to the VWFA would be expected to cause alexia in a literate person without prior brain process, but such a case has not previously been reported to our knowledge. Here, we report the case of a previously-healthy 63-year-old man with the acute onset of alexia without other significant impairments. Magnetic resonance imaging (MRI) of the brain revealed a small ischemic stroke localized to the inferior left occipitotemporal cortex, corresponding to the approximate location of the putative VWFA. Characteristic of pure alexia, testing in the weeks following the stroke revealed a letter-by-letter reading strategy and a word length effect on single word reading. Formal visual field testing was normal. There was no color anomia, or object or face recognition deficits, although a mild agraphia may have been present. This case of acute-onset alexia in a previously normal individual due to a small stroke restricted to the VWFA and sparing occipital cortex and white matter pathways supports the conclusion that the VWFA is crucial for reading.

Keywords:

• Alexia
• Pure alexia
• Alexia without agraphia
• Visual word form area
• Agraphia
• Dyslexia
• Dysgraphia
• Reading

Author Contributions: Drs. Goldberg, Turkeltaub, Quinn, Cantor, and Coslett contributed to the conception and design. Drs. Goldberg, Turkeltaub, Postman-Caucheteux, Palovcak, and Coslett contributed to acquisition of data and analysis and interpretation of data. Dr. Goldberg drafted the article. Drs. Goldberg, Turkeltaub, Postman-Caucheteux, and Coslett, revised it critically for important intellectual content. All authors provided final approval of the version submitted.

Funding: No specific funding reported Competing interests: None. Patient consent: Obtained. Ethics approval: This study was conducted with the approval of the University of Pennsylvania Institutional Review Board.