An investigation of confrontation naming performance in Alzheimer's dementia as a function of disease severity

The confrontation naming performance of persons with dementia of the Alzheimer's type (DAT) is a widely investigated area, yet considerable confusion remains as to the precise nature of the breakdown, in particular whether the deficit is related to either a procedural or structural semantic deficit that remains uniform over the course of the disease. The present study undertook a detailed error analysis of the naming responses of 23 subjects with DAT, grouped on the basis of their dementia severity into three groups of mild (n = 8), moderate (n = 7), and moderately severe (n = 8), to investigate the pattern of progression of anemia in DAT. The results provided strong support for the proposal that anemia in DAT changes both quantitatively and qualitatively over the course of the disease, with the naming responses of subjects severely affected by the disease reflecting increased compromise of core semantic structures and processes. In the milder stages of DAT, however, the anemia is characterized by deficits in the procedural routines used to interrogate information in the semantic representation. That these procedural deficits in early-stage DAT are related to disruption of the centralized higher-order cognitive process of attention is suggested, but requires further empirical validation