Mini-Mental State Examination item scores as predictors of Alzheimer's disease: incidence data from the Kungsholmen Project, Stockholm.

Abstract

The present study examined the power of individual Mini-Mental State Examination (MMSE) items in predicting incidence of Alzheimer's disease (AD). In addition, 3-year longitudinal changes in MMSE items were contrasted between incident AD and nondemented persons. A population-based group of very old adults, 75-95 years of age, were followed longitudinally. Of the original 327 participants, 32 were diagnosed with probable or possible AD after a 3-year follow-up interval and 189 remained nondemented. Cognitive performance was indexed by the individual item scores from the MMSE. These sample from multiple domains of cognitive functioning, including visuospatial skill, recent memory, orientation to time and place, language, and the ability to sustain attention. Items dealing with delayed episodic memory and orientation to time were significant predictors of AD incidence, independent of age, gender, and years of education, as determined by logistic regression analyses. Longitudinally, changes in performance were largest among individuals diagnosed as incident AD, although the magnitude of change across items was highly variable. In particular, decline was relatively small for the delayed memory item, whereas most other measures showed dramatic decline in performance among individuals with incident AD. Individual MMSE items, especially those with some type of episodic memory referent, were the best predictors of incident cases of AD. Moreover, MMSE items displayed differential rates of changes, particularly for the incident AD participants.