Preservation of memory for people in semantic memory disorder: Further category-specific semantic dissociation.

ML, a 70-year-old right-handed woman, presented with a history of semantic memory difficulties and a profound anomia affecting both proper nouns and common nouns following a left-hemisphere CVA some years earlier. She was found to show a striking contrast between her ability to make fine-grained semantic distinctions between objects and animals, on the one hand, and famous faces and names, on the other. Although she was impaired on a series of picture and word semantic comprehension tests when the stimuli consisted of exemplars of object and animal categories, her performance was intact when the materials comprised famous faces and names, suggesting a dissociation between the representation of person-specific knowledge and other categories of semantic information. A number of cases have been reported in which person-specific knowledge has been selectively impaired, but we would suggest that our case provides the clearest evidence so far of the reverse dissociation, in which person-specific knowledge is selectively preserved. We speculate on possible differences in the ways in which person-specific knowledge may be represented, relative to information about objects and animals.