The third alexia.

A variety of alexia has been demonstrated that can be distinguished from the two classically recognized types of alexia. This reading disorder is seen in patients with a dominant frontal lobe pathologic condition that has produced a motor language disturbance (Broca aphasia) and is sufficiently disabling to deserve consideration as a variety of alexia. Functionally, the frontal reading disturbance differs from the other two types in that the patient comprehends meaningful content words better than relational or syntactic structures. Four factors that may underly frontal alexia have been noted: (1) gaze paresis, (2) inability to maintain verbal sequences; (3) inability to comprehend syntactic structure, and (4) literal alexia.