Analysis of Naming Errors in Healthy Aging, Mild Cognitive Impairment,and Alzheimer's Disease

The aim of this study was to document the functional origin of anomia in mild cognitive impairment in comparison to Alzheimer's disease and healthy cognitive aging. An oral naming task of 260 pictures was administered to 20 individuals with mild cognitive impairment, 5 with mild Alzheimer's disease, and 15 healthy controls. The mean total number of errors and types of naming errors were compared across the groups. The effect of psycholinguistic parameters and the efficacy of semantic and phonological cueing were also analyzed. Results showed a significant difference among the three groups' total number of naming errors (Alzheimer's disease > mild cognitive impairment > healthy controls). Similar types of naming errors were found among the groups and mainly consisted of coordinate semantic paraphasias. Further, less familiar words were associated with greater error probability in all groups. Finally, based on error types, psycholinguistic parameters, and efficacy of cueing, the main origin of anomia was determined for each participant and different patterns were observed among the three groups. In healthy controls, the origin of anomia was lexical. In mild cognitive impairment, the origin of anomia was lexical for 60% and semantic for 40% of participants. In Alzheimer's disease, a degradation of fine and distinctive semantic features seems to be the main cause of anomia. Although the present data are limited due to small sample size, they will be useful in the development of appropriate interventions aiming to reduce anomia in the elderly.