Cognitively-based Treatments of Acquired Dyslexias

Acquired disorders of reading (acquired dyslexia) are common in patients with aphasia subsequent to left hemisphere stroke. Even when language functions recover sufficiently to enable the patient to return to work, continuing dyslexia often interferes significantly with job performance. This study will evaluate cognitive therapies for the treatment of acquired dyslexia.

Each therapy is based upon a cognitive neuropsychological model of reading; the therapies target specific types of reading deficit and stem from the question of re-learning versus re-organization of function. The therapies focus on dyslexic disorders stemming from the following underlying deficits: 1) impaired access to the orthographic word form from the visual modality (pure alexia); 2) impaired orthographic/phonologic connections (phonologic/deep dyslexia); and 3) decreased ability to hold phonologic codes in memory (phonologic text alexia).

Participants in this study will undergo a comprehensive and detailed battery of reading and reading-related tests to determine the underlying impairment causing the reading deficit. Based upon the results of these tests, the patient's dyslexic disorder will be characterized and, if appropriate, the patient will be assigned to one of the treatment programs devised specifically for that type of deficit. Treatment programs are evaluated for efficacy by comparing the accuracy and speed of reading pre- and post-treatment.