Assessing the cognitive abilities that differentiate patients with Alzheimer's disease from normals: single and multiple factor models.

Abstract

Understanding the structure of cognitive abilities in Alzheimer's disease (AD) has considerable practical and theoretical importance. Some investigators have argued that a single cognitive process underlies the deficits seen in AD, while others have argued for multiple cognitive processes. As deficits in cognitive abilities may reflect the pathological process or processes occurring in AD, determination of the structure of abilities in AD is important. The purpose of this study was to assess the utility of single and multiple ability factor models in differentiating patients with AD from normals. Findings show that although a single factor model accounts for a large part of the variability of a battery of measures used to differentiate patients and normals, a multiple factor model performed substantially better based on multiple fit criteria. At least in this sample, a multiple ability factor model of cognitive abilities fit data better than a single factor model in differentiating patients with AD from normals.