Preserved object recognition and reading comprehension in optic aphasia.

Optic aphasia is characterized by the ability to name from description and palpation but an inability to name visually-presented objects. Although originally attributed to a disconnection of visual information from object names, optic aphasia is often considered to be a mild form of visual agnosia. We describe a patient with optic aphasia who could access semantic information relevant to objects he could not name and comprehend written words he could not read. These data suggest that, at least in certain cases, this visual modality-specific naming impairment may not be attributable to impaired visual recognition. We suggest that this patient's preserved object recognition and reading comprehension was mediated by a semantic system supported by the right hemisphere.