A Brief Dementia Test with Subjective and Objective Measures

Abstract

Background: The development of an effective brief dementia test will help in the early identification of dementia. Aim: This study investigates the diagnostic utility of a brief cognitive test for dementia which combines a short subjective informant-rated questionnaire (AD8) with an objective cognitive measure (Mini-Mental State Examination, MMSE) or its subcomponents. Methods: Subjects with mild dementia (Clinical Dementia Rating Scale score ≤1) were matched with community-dwelling, cognitively intact controls. MMSE and Clinical Dementia Rating Scale were administered to all subjects, while AD8 was completed by a reliable informant. Receiver operating characteristics analysis determined the diagnostic accuracies of AD8, MMSE, and AD8 combined with MMSE (AD8+MMSE). Stepwise logistic regression identified the subcomponents of MMSE which, combined with AD8, best discriminated dementia patients from controls. Results: The AD8 (area under the curve [AUC] = 0.92, 95% confidence interval [CI] 0.89-0.95) was superior to the MMSE (AUC = 0.87, 95% CI 0.83-0.92) in discriminating mild dementia patients from controls, and AD8+MMSE (AUC = 0.95, 0.92-0.98) increased its superior discrimination over MMSE alone. AD8 combined with three-item recall and intersecting pentagon copy (AUC = 0.95, 95% CI 0.92-0.97) performed as well as AD8 combined with full MMSE. Conclusion: AD8 combined with the MMSE subcomponents three-item recall and intersecting pentagon copy has excellent diagnostic utility and is a promising brief cognitive test for early dementia.