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.
ABSTRACT
BACKGROUND: Rapid eye movement sleep behaviour disorder (RBD) is associated with reduced cardiac 123 I-metaiodobenzylguanidine (MIBG) uptake and often precedes the onset of Lewy body (LB) disorders. We investigated the role of cardiac 123 I-MIBG scintigraphy in relation to probable RBD for the clinical diagnosis of prodromal dementia with Lewy bodies (DLB) in memory clinics. METHODS: We reviewed clinical profiles of 60 consecutive patients who underwent cardiac 123 I-MIBG scintigraphy in our memory clinics. The diagnostic threshold of 2.20 was used as the cut-off for the heart-to-mediastinum ratio at the delayed phase. RESULTS: Cardiac 123 I-MIBG abnormality was identified in 28 patients at baseline; six were cognitively unimpaired, six had mild cognitive impairment (MCI)-LB, and 16 had probable DLB based on the National Institute on Aging and Alzheimer's Association Research Framework. Although the number of core features increased in accordance with the progression of three cognitive categories, there were no differences in the prevalence of probable RBD and the cardiac MIBG scintigraphy indices among them. During the observation period, two cognitively unimpaired patients with probable RBD progressed to MCI-LB, and three MCI-LB patients with probable RBD developed DLB. The prevalence of final diagnosis of probable MCI-LB or DLB was significantly higher in these patients (85%) than the remaining 32 patients without (9%). Of 25 patients with probable RBD, 22 (88%) had a cardiac 123 I-MIBG abnormality regardless of cognitive conditions. Only one patient consulted a sleep centre for the abnormal sleep behaviour before visiting our memory clinics. Regarding the gender differences, male predominance was not identified and sleep-related injury more frequently occurred in men (7/12, 58%) than in women (1/10, 10%). CONCLUSIONS: Proactive detection of probable RBD plus cardiac 123 I-MIBG abnormality provides the opportunity for an early diagnosis of prodromal DLB in memory clinics. This approach warrants further follow-up studies with polysomnographic and pathological verification.
