Dissociation between knowledge of living and nonliving things in dementia of the Alzheimer type

Abstract

Patients who survive herpes simplex encephalitis (HSE) sometimes present a category-specific disorder for living things. Since HSE specifically involves the temporolimbic structures of both hemispheres, these structures could play a critical role in processing and storing information about living things. If this were the case, a category-specific disorder for the same items should also be observed in the early stages of dementia of the Alzheimer type (DAT) as the temporolimbic structures are often severely affected in this condition. To test this hypothesis, we administered to 15 DAT patients and to 10 normal controls a confrontation-naming task and a verbal associates recognition task, with both living and nonliving items as stimuli. The hypothesis was confirmed, since DAT patients performed worse with living than with nonliving items, and scored worse than normal controls on the living but not the nonliving items.