Conceptual decline in Alzheimer's disease

Introduction. In Alzheimer's disease a gradual and progressive loss of semantic information takes place. A question of great importance on both the theoretical and practical levels is which concepts are the first to be lost and which are the most resistant to deterioration. Some theories maintain that the beginning of the disease stimuli belonging 10 certain conceptual categories are most affected by loss. Method. A group of twenty-two patients with mild to moderate Alzheimer's disease was compared with a group of healthy people of similar age, gender, and educational level, in naming pictures of objects from eight semantic categories; four in the domain of living things and four in the domain of inanimate objects. In each group 16 were women and 6 trien. The mean age was 74 in both groups. Statistical analysis. In order to know if differences between Alzheimer patients and control subjects are determined by the semantic categories, ANOVAS were performed taking the group (patients vs control) and the type of stimulus as factors. Results. The scores of the Alzheimer patients are statistically lower than those of the control subjects, but differences are determined by the features of each stimulus (familiarity, frequency, age of acquisition) more than, belonging to a specific category. Discussion. The results indicate that the specific characteristics of each stimulus contribute more to concept loss than does belonging to a certain category, especially the frequency of use and the age of acquisition.