Screening for Alzheimer's dementia at age 78 with short psychometric instruments

Abstract

To date, no single instrument has proved to be adequate for screening for Alzheimer's dementia (AD). The aim of this study was to identify a combination of instruments which were highly sensitive for screening late onset AD. Subjects were drawn from the Vienna TransDanube Aging (VITA) study. This is an interdisciplinary, longitudinal community-based cohort study of the 21st and 22nd district of Vienna (Austria). Data refer to the cohort of 478 individuals at age 78 who took part in the first follow-up investigation of the VITA study. The psychometric instruments which were investigated were: the Ten-Point Clock Test, the Human-Figure Drawing Test, a Delayed Selective Reminding Test, Naming, the Trail Making Test-B, and Verbal Fluency. Further instruments were the Pocket Smell Test, and Subjective Memory Complaints. Data were analyzed using logistic regression analyses and cross validation. A combination of the Delayed Selective Reminding Test and Verbal Fluency was best for screening AD (R2 = 0.38, main model). An area under the ROC curve of 0.829 was reached. This model discriminated between subjects with incident AD and subjects who did not have incident AD with a sensitivity of 91% and a specificity of 56%. The combination of an episodic memory test and a test of verbal fluency was an effective way of screening for AD.