Reading, writing, and their disorders

Reading and writing are complex forms of communication. Disorders of these abilities reflect this complexity. Although distinct syndromes do exist, it is more common to see these disorders in the context of related dysfunction. For example, alexia and agraphia commonly occur together. Not only do they occur together, but frequently, although not exclusively, a patient with both has similar patterns of performance in each modality. Reading, the transformation of written symbols into spoken output, is intimately related to visual input and speech. Disorders of these abilities are commonly reflected in alexia. Writing, the transformation of oral input (writing to dictation) or conceptual thought into written symbols, is interconnected with speech and motor function. Again, disorders of these abilities are commonly reflected in agraphia. Understanding alexia and agraphia allows insight into multiple realms of left hemispheric dysfunction and provides significant clinical insight into patients with left hemispheric lesions.