Cross-modal recognition disorders for persons and other unique entities in a patient with right fronto-temporal degeneration

We describe a patient (CD), with a right fronto-temporal degeneration, who showed massive defects in the recognition of familiar people and severe behavioural disorders. CD scored in the normal range on tests of episodic memory, attention and visual-spatial abilities, and obtained mildly abnormal scores on naming and executive functions tests. CD was then studied and matched with a left brain-damaged patient (IG), comparable to her as for education, naming score and general cognitive impairment, on several tasks, exploring recognition of familiar people and of other instances of 'unique entities'. On specific tasks of face recognition, she obtained normal results on perceptual tests, but highly pathological scores on mnesic-associative tasks. A similar defect was found when identification was based on the person's voice or on a verbal definition. The cross-modal nature of CD's disorder was confirmed by results of a test, in which person-specific information available from photographs and from names was directly compared. In order to evaluate if CD's recognition disorder: (a) was the consequence of a general semantic defect, (b) was specific for people, or (c) also concerned other instances of 'unique entities', we matched her capacity to name and recognize the pictures of items belonging to various categories of knowledge with those concerning famous monuments and famous people. CD identified items belonging to semantic categories much better than those considered as 'unique entities' and, within the latter, obtained slightly better results with famous monuments than with famous persons. MRI showed a bilateral atrophy of the antero-inferior parts of the temporal lobes, more pronounced in the right side. About 2 years after the onset of the symptomatology, CD became untestable, due to the development of a severe motor neuron disease