Visual anomia: a unidirectional disconnection.

A right-handed patient with a complete right homonymous hemianopia could not name objects seen in her left hemifield but could always select an object from an assortment when the object was named. If the right hemisphere was devoid of auditory language function, we must postulate separate transcallosal pathways from visual to verbal and from auditory language to visual information. Because only the former pathway was interrupted, our patient exhibited a "unidirectional" disconnection.