Abstract
Although the term prosopagnosia recently is considered to refer only to “agnosia for well-known faces ” , almost all prosopagnosics have impairment of discrimination and learning of unknown faces. Only five exceptional cases of prosopagnosia with nomal discrimination of unknown faces have been reported until now. We report the sixth case of prosopagnosia with intact discrimination of unfamiliar faces.
A 73-year-old right-handed female complained of disability to identify visually the faces of well-known persons following a slight attack of apoplexy. Perimetry revealed left homonymous hemianopsy. Neither hemiparesis nor hemihypesthesia was detected. Language and praxis were quite intact. Besides prosopagnosia, no visual agnosia was observed. Auditory and tactile agnosias were not detected.
The patient was not able to identify visually her family members before they talk to her. She could recognize none of 20 photographs of famous personalities, which we used in order to assess facial identification. She also complained of loss of imagery of well-known faces. On the other hand, the patient showed quite normal performance on the tasks concerning discrimination and learning of unknown faces.
By means of CT scan, occlusion of the lateral branch of the right posterior cerebral artery was considered to cause such prosopagnosic symptoms, in stead of occlusion of the main trunk of this artery which may be the ordinary cause of prosopagnosia.
