Journal Article

What best differentiates Lewy body from Alzheimer's disease in early-stage dementia?

Pietro Tiraboschi, David P. Salmon, Lawrence A. Hansen, Richard C. Hofstetter, Leon J. Thal and Jody Corey-Bloom

in Brain

Published on behalf of The Guarantors of Brain

Volume 129, issue 3, pages 729-735
Published in print March 2006 | ISSN: 0006-8950
Published online January 2006 | e-ISSN: 1460-2156 | DOI: http://dx.doi.org/10.1093/brain/awh725
What best differentiates Lewy body from Alzheimer's disease in early-stage dementia?

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To determine which clinical feature(s) [among visual hallucinations (VH), extrapyramidal signs (EPS) and visuospatial impairment] in the earliest stages of disease best predicted a diagnosis of dementia with Lewy bodies (DLB) at autopsy, first-visit data of 23 pathologically proven DLB and 94 Alzheimer's disease cases were compared. There were no group differences with regard to age, gender, education or global severity of dementia at presentation (mean Mini-Mental State Examination: 24.0 versus 25.0, mean Dementia Rating Scale: 123.6 versus 125.7). DLB patients at initial presentation displayed an increased frequency of VH (P = 0.001), but not EPS (P = 0.3), compared to Alzheimer's disease patients. However, only a minority of DLB cases had either VH (22%), EPS (26%) or both (13%). In contrast, although not a core feature, visuospatial/constructional impairment was observed in most of the DLB cases (74%). Among clinical variables, presence/recent history of VH was the most specific to DLB (99%), and visuospatial impairment was the most sensitive (74%). As a result, VH at presentation were the best positive predictor of DLB at autopsy (positive predictive value: 83% versus 32% or less for all other variables), while lack of visuospatial impairment was the best negative predictor (negative predictive value: 90%). We conclude that the best model for differentiating DLB from Alzheimer's disease in the earliest stages of disease includes VH and visuospatial/constructional dysfunction, but not spontaneous EPS, as predictors. This suggests that clinical history plus a brief assessment of visuospatial function may be of the greatest value in correctly identifying DLB early during the course of disease.

Keywords: Alzheimer's disease; dementia with Lewy bodies; core clinical features; diagnostic accuracy; DLB = dementia with Lewy bodies; DRS = Dementia Rating Scale; DRS-C = DRS construction subscale; EPS = extrapyramidal signs; MMSE = Mini-Mental State Examination; NPV = negative predictive value; PPV = positive predictive value; VH = visual hallucinations

Journal Article.  5688 words. 

Subjects: Neurology ; Neuroscience

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