Diagnostic accuracy of dementia with Lewy bodies

Background: Diagnostic criteria for dementia with Lewy bodies (DLB) are sti ll evolving. No data exist on prospective differentiation of DLB and Alzhei mer disease (AD). Objective: To examine the clinician's diagnostic accuracy for DLB and analy ze factors contributing to false-positive DLB diagnoses. Methods: A prospective series of 10 patients with clinically diagnosed DLB who came to autopsy was compared with 32 autopsy-confirmed cases of DLB (27 Le Ny body variant, 5 diffuse Lewy body disease) and 20 autopsy-confirmed cases of AD (matched on age, sex, education, and initial Mini-Mental State Examination score) with regard to distinguishing and/or confounding clinica l features. Results: The clinical diagnostic accuracy for DLB was 50%, with 5 of the 10 patients clinically presumed to have DLB confirmed at autopsy. Of the 5 mi sdiagnosed cases, 4 had AD and 1 had progressive supranuclear palsy. The mi sdiagnosed DLB cases who had pure AD had fewer hallucinations (25%) than th ose with Lewy body variant (63%) or diffuse Lewy body disease (100%) (P = . 048); however, an equal amount of spontaneous tin the absence of neurolepti cs) extrapyramidal signs was found. There were no differences among groups with regard to daily fluctuations in cognition or falls. Compared with the AD control group, the misdiagnosed DLB cases with pure AD showed significan tly more spontaneous extrapyramidal signs (P less than or equal to.02). Conclusions: The clinician's diagnostic accuracy for DLB was poor. Early sp ontaneous extrapyramidal signs in AD were associated with false-positive cl inical diagnoses of DLB. The distinction between DLB and AD may be improved by greater emphasis on hallucinations.