HOW PURE IS PURE ALEXIA? A NEUROPSYCHOLOGICAL ANALYSIS OF A CASE SERIES OF PATIENTS WITH ALEXIA DUE TO LEFT HEMISPHERIC STROKES

The aim of this study was to analyze a case series with acquired alexia after stroke within the posterior areas of the left hemisphere, in the context of the current criteria for pure alexia and their relevance to the set of symptoms observable in clinical practice. Seven patients with ischemic strokes and an initial diagnosis of pure alexia were enrolled for detailed analysis. The evaluation consisted of neuropsychological assessment in the form of standardized tests and non-standardized reading tasks, while oculomotor activity during reading was measured. Language functions, visual object and space perception, verbal and nonverbal memory, and visuospatial constructional ability were among the domains assessed. In five of the participants, pure alexia was recognized based on sig- nificant and specific discrepancies between test scores, indicating primary abnormalities in the visual processing of letter strings as a basic mechanism of the disorder. In most of the patients, coexisting cognitive deficits were revealed; however, these were dispropor- tionately milder and less functionally significant than reading disturbances. Pure alexia is a relatively rare disorder after a stroke, but it considerably affects the quality of everyday independent functioning. Its clinical characteristics in practice rarely meet all the criteria proposed in the subject literature. The differential diagnosis of this form of alexia and other reading disorders requires detailed clinical analysis.