A right-handed 64-year-old female who complained of difficulty in identifying familiar faces was investigated in a series of face perception tests(face matching, recognition of age and sex, and meaning of facial expressions), face identification(including faces of family members and famous people as retrograde examples and her doctors’ faces as anterograde examples)and other neuropsychological abilities. Her scores on the face perception tests were almost normal. Her general cognitive function measured by MMSE was substantially normal. In contrast, she was unable to identify any of the anterograde or retrograde familiar faces and failed to experience any sense of familiarity with those faces. In addition, she could not recognize the voices of family members or her doctor, despite being able to recognize the age and sex of the voices. Her knowledge about famous people was also degraded. On the other hand, she could describe the personalities of her family members and doctors. Memory for personal events in the recent and remote past was preserved, while that for past social events was severely disturbed. In addition to impairment in identification of familiar faces, she had severe problems with identifying famous buildings. She also presented with Gogi (word meaning) aphasia and impaired semantic memory for some common objects.
Tyrrell et al. and Kazui et al. have reported similar semantic dementia(SD)cases. McNeil et al. examined such an SD patient on covert recognition of faces in detail. That patient showed no covert recognition effects, and consequently they attributed the result not to a deficit of access to face recognition units but to impairment of the face recognition units themselves. Their hypothesis seems to provide an explanation for the disturbance of anterograde and retrograde face memory of our patient. Namely, damage to the face recognition unit system would explain not only her loss of retrograde face representations, but also her impairment in making new face representations.
Neuroanatomical studies with CT and MRI scans revealed striking focal atrophy in the anterior part of her bilaterally temporal lobes (which was more conspicuous on the right) and the basal part of the frontal lobes. SPECT images demonstrated hypoperfusion in these areas.
The present study suggests that the right anterior temporal lobe, especially its latero-basal aspect, may play a crucial role in the storage of face recognition units. Furthermore, the pathological process of lobar atrophy with right temporal predominance might affect the whole face recognition system, resulting in a storage deficit for faces.
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