Visual memory and perceptual impairments in prosopagnosia.

A patient who suffered traumatic hematomas of both occipitotemporal regions, but who had normal visual acuity, language, and cognitive functions, could not recognize faces of family members, celebrities , or recent acquaintances (prosopagnosia). He could distinguish same from different faces when they were presented simultaneously, but could not recognize faces that had been presented to him 90 seconds earlier. He could read and name objects correctly, but could not recognize any previously viewed object if it was reexamined later with other objects of the same semantic class. He had no difficulty copying complex figures, but synthesized incomplete visual information poorly and pursued an abnormal visual search strategy. We suggest that prosopagnosia is part of a more general inability to distinguish among objects within a visual semantic class. It results from impaired visual memory and perception caused by visual association cortex damage and interruption of the inferior longitudinal fasciculus connecting visual association cortex and temporal lobe.