Naming of objects, faces and buildings in mild cognitive impairment.

Accruing evidence suggests that the cognitive deficits in very early Alzheimer's Disease (AD) are not confined to episodic memory, with a number of studies documenting semantic memory deficits, especially for knowledge of people. To investigate whether this difficulty in naming famous people extends to other proper names based information, three naming tasks - the Graded Naming Test (GNT), which uses objects and animals, the Graded Faces Test (GFT) and the newly designed Graded Buildings Test (GBT) - were administered to 69 participants (32 patients in the early prodromal stage of AD, so-called Mild Cognitive Impairment (MCI), and 37 normal control participants). Patients were found to be impaired on all three tests compared to controls, although naming of objects was significantly better than naming of faces and buildings. Discriminant analysis successfully predicted group membership for 100% controls and 78.1% of patients. The results suggest that even in cases that do not yet fulfil criteria for AD naming of famous people and buildings is impaired, and that both these semantic domains show greater vulnerability than general semantic knowledge. A semantic deficit together with the hallmark episodic deficit may be common in MCI, and that the use of graded tasks tapping semantic memory may be useful for the early identification of patients with MCI.