prosopagnosia
n. a form of visual agnosia in which the ability to perceive and recognize faces is impaired, whereas the ability to recognize other objects may be relatively unaffected. The term was originally limited to impairment following acute brain damage, but a congenital form of the disorder has since been recognized. Prosopagnosia can be distinguished from prosopamnesia, which is an abnormal difficulty in remembering faces, even though they are perceived normally: The condition may be congenital or acquired.