C rossmodal agnosia for familiar people as a consequence of right infero polar temporal atrophy

A 60-year-old, right-handed woman, with no focal brain lesions, suffered from a progressive impairment in recognising people of personal relevance and public figures familiar to her in the premorbid period. The patient did not suffer from general cognitive deterioration. There was no ecological or clear psychometric evidence of visuoperceptual or visuospatial deficits. Her defective person recognition was not overcome by extra-facial (e.g., observing animated people in their usual surroundings) or extra-visual information (e.g., listening to the voice). Moreover, presenting the correct name in the presence of an unrecognised familiar person failed to prompt her familiarity judgement, or retrieval of the relevant biographical knowledge. The patient also had some recognition difficulties with famous buildings and songs as well as with some common objects. It is argued that the patient's difficulty in identifying familiar people was the consequence of progressive loss of stored exemplars of familiar persons and perhaps also of some other "unique items" (famous songs and monuments) in an independent subsystem of semantics that we term "exemplar semantics." We discuss the associative (semantic) nature and specificity of the deficit in person knowledge, the possible top-down negative influences of the loss of exemplars in the person recognition system, and the link between the disorders and the right/left temporal lobe.