In 1891 and 1892 Dejerine published two cases primarily characterized by the acquired inability to read, the first associated with an impairment of writing ability and the second with preserved writing. In both cases, the responsible pathology had a different anatomical location. Patients so afflicted are able to write, but cannot read their own written words. The primary deficit is an inability to comprehend written material. Patients readily understand words spelled aloud or words written on the palm.
Some patients demonstrate a literal alexia, unable to recognize any written letters.
Most can recognize some individual letters and, with practice, can learn to read most letters out loud and thereby recognize words auditorily. Other aspects of language, such a fluency, auditory comprehension, writing, and repetition are normal. A mild anomia is common but not invariably present. Sensory loss and motor dysfunction are not observed. Deficits in color vision and color naming may also be seen.