Towards optimizing the diagnosis of Lewy body dementia: Lessons from the NACC

INTRODUCTION The diverse presentations and co‐pathologies of Lewy body dementia (LBD) present a diagnostic challenge. Utilizing the National Alzheimer's Coordinating Center (NACC) dataset, this study aimed to evaluate the concordance of premorbid diagnoses of LBD in individuals with autopsy‐confirmed neocortical Lewy body disease. METHODS Demographics, clinical and neuropsychological presentations, Lewy body pathology, and Alzheimer's disease (AD) co‐pathology were related to clinical diagnosis. RESULTS Diagnosis of LBD had high specificity but low sensitivity, with fewer than half of autopsy‐confirmed cases having received an LBD diagnosis. AD was the most common misdiagnosis. Participants diagnosed with AD were more likely to be female, to have a more amnestic phenotype, and to harbor a higher burden of AD co‐pathology, and were less likely to have documented clinical features characteristic of LBD. DISCUSSION These results highlight the need to improve LBD diagnosis in research and clinical settings, a need that emerging biomarkers may help address. Highlights Less than half of cases with neocortical Lewy bodies were diagnosed with Lewy body dementia (LBD) Alzheimer's disease (AD) was the most common misdiagnosis Cases misdiagnosed were more likely to be female Cases diagnosed with AD presented with a more amnestic phenotype Cases diagnosed with AD had more AD co‐pathology