Pure Alexia

Abstract

Pure alexia, one of the major subtypes of acquired dyslexia has been recognized for more than a century. The French neurologist Dejerine described it in 1892. It was called “pure” alexia because in this disorder reading alone is affected. Even writing and spelling could be unaffected. In all other forms of acquired dyslexia, some form of impairment of writing and spelling will be seen. Dejerine attributed this disorder to an isolation of the center for optic images of letters that is situated in the left angular gyrus from both visual cortices. He argued that the patients were unable to read because of the lack of access to this center through visual stimulation. However since the lesion is outside the language zone per se the patients are still able to understand speech, speak and also write. Hence “pure” alexia since it is a pure reading disorder not associated with any other language disorder.