SEMANTIC SPACE IN ALZHEIMERS-DISEASE PATIENTS

A within-category sorting task was used to investigate conceptual relations from 2 semantic categories (animals and occupations) in mild and moderately impaired Alzheimer's disease (AD) patients. A multidimensional scaling analysis was applied to the data. The resulting 2-dimensional solutions indicated that mildly affected AD patients sorted within-category terms in a manner largely consistent with controls' performance but were less consistent in their application of domain knowledge. Moderate AD patients' solutions were less similar to controls' solutions. Mild AD patients' explanations of their sorting schemes were similar to those given by controls but less focused. Together these findings suggest that attribute knowledge may remain largely accessible in mild AD; however a deficiency in recruiting reflective processes in the service of task-related goals may limit the selective application of this information.