A simple method to evaluate the pentagon copy test of the Mini-Mental State Examination for the differentiation of dementia with Lewy bodies.

Abstract

There are many commonalities between the clinical symptoms of dementia with Lewy bodies (DLB) and those of Alzheimer's disease (AD). The accurate differentiation of these two diseases is an important neuropsychological issue. The Mini-Mental State Examination (MMSE) is often used as a screening test for dementing disorders. We created evaluation items for the pentagon copy test of MMSE and developed a simple, highly accurate evaluation method for differentiating DLB in combination with conventional evaluation items such as the Qualitative Scoring MMSE Pentagon Test (QSPT). Subjects were divided into three groups: DLB (n = 119), AD (n = 50), and Normal (n = 26). The severities of DLB and AD ranged from mild cognitive impairment (MCI) to mild dementia. We compared the results of the pentagon copy test. We found that the rates of patients with abnormalities in "motor incoordination" and "gestalt destruction" were higher in the DLB group than the AD group. Furthermore, receiver operating characteristic curve analysis suggested the differentiation of DLB with high accuracy (sensitivity: 0.70, specificity: 0.78) using the criterion of patients meeting one of the following three characteristics: "the number of angles on QSPT: scores other than 4," "major tremor (Parkinsonism-related tremor) is present," and "gestalt destruction (distortion in overall coherence) is present." This evaluation method may be clinically useful for evaluating MCI to mild DLB patients because the burden on patients is low.