Research evaluation and prospective diagnosis of dementia with Lewy bodies.

OBJECTIVE To evaluate the relative merits of recently developed criteria for dementia with Lewy bodies (DLBs) in a longitudinal study of dementia. DESIGN The diagnosis of DLBs was used in combination with other clinical diagnosis. Patients were classified primarily based on the NINCDS-ADRDA (National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association) clinical criteria for probable or possible Alzheimer disease, or with other disease process that can cause dementia (eg, Parkinson disease), and secondarily according to the consensus guidelines for DLBs. This "double" clinical diagnosis was implemented to capture different pathological entities. The neuropathological diagnosis of Lewy bodies was made with monoclonal antibodies against alpha-synuclein. SETTING Multidisciplinary research clinic. RESULTS Prospective application of the consensus guidelines for DLBs from January 1, 1997, to September 29, 2000, identified 11 patients having the diagnosis of probable DLBs and 35 having possible DLBs. The diagnosis of probable or possible DLBs was associated with probable Alzheimer disease in 34 patients, with possible Alzheimer disease in 5 patients, with Parkinson disease in 2 patients, and with other disease processes in 2 patients. Three patients were diagnosed as having probable DLBs alone. An autopsy was performed in 26 of the cases who were clinically examined during the study period. Cortical Lewy bodies were identified in 13 cases; 4 had had premortem diagnosis of DLBs (sensitivity, 30.7%; specificity, 100%). CONCLUSIONS The prospective validation of the clinical criteria for DLBs showed poor accuracy in this series. We believe that current criteria for DLBs are useful when DLBs occur in isolation, but have low sensitivity when Lewy bodies coexist with the pathological abnormalities of Alzheimer disease.