Alexia (condition) - Classification

Classification

There are two groups of alexia.

• The first or main group is "the central dyslexia" group which includes surface dyslexia, semantic dyslexia, phonological dyslexia, and deep dyslexia.
• The second group, "the peripheral dyslexia" group, includes neglect dyslexia, attentional dyslexia, and pure alexia which is also known as alexia without agraphia.

Classification of alexia depends on the site of anatomic damage and whether agraphia (deficits in writing) and/or aphasia (deficits in oral language) is present. Alexia and agraphia are often associated with aphasia, but it is possible to have alexia and agraphia without aphasia. When aphasia is not present, alexia is categorized as either: 1) alexia without agraphia (pure alexia or word blindness) which is associated with left occipital lobe damage, or 2) alexia with agraphia which is associated with lesions of the left angular gyrus.