Gunter, Jeffrey L.

Abstract Introduction Our goal was to develop cut points for amyloid positron emission tomography (PET), tau PET, flouro‐deoxyglucose (FDG) PET, and MRI cortical thickness. Methods We examined five methods for determining cut points. Results The reliable worsening method produced a cut point only for amyloid PET. The specificity, sensitivity, and accuracy of cognitively impaired versus young clinically normal (CN) methods labeled the most people abnormal and all gave similar cut points for tau PET, FDG PET, and cortical thickness. Cut points defined using the accuracy of cognitively impaired versus age‐matched CN method labeled fewer people abnormal. Discussion In the future, we will use a single cut point for amyloid PET (standardized uptake value ratio, 1.42; centiloid, 19) based on the reliable worsening cut point method. We will base lenient cut points for tau PET, FDG PET, and cortical thickness on the accuracy of cognitively impaired versus young CN method and base conservative cut points on the accuracy of cognitively impaired versus age‐matched CN method.

ABSTRACT Background The clinical course of dementia with Lewy bodies patients is heterogeneous. The ability to more accurately prognosticate survival is important. Objective The objective of this study was to investigate hippocampal volume as a predictor of survival in dementia with Lewy bodies patients. Methods Survival analysis for time from onset of cognitive symptoms to death was carried out using Cox proportional hazards models. Given their age and total intracranial volume, patients were dichotomized into low/medium (0%‐66.7%) and high (66. 7%‐100%) hippocampal volume categories. The models using these categories to predict survival were adjusted for field strength, APOE ε4 status, and estimated onset age of cognitive problems. Results We investigated 167 consecutive patients with dementia with Lewy bodies. The median age at MRI was 72 years (interquartile range 67‐76), and 80% were male. The median time from estimated first cognitive symptom to death was 7.4 years (interquartile range:5.7‐10.2). Lower hippocampal volumes were significantly associated with higher risk of death (hazard ratio 1.28; 95% confidence interval 1.04‐1.58; P = .024). The predicted median survival for participants with onset of cognitive symptoms at age 68 was 10.63 years (95% confidence interval 8.66‐14.54) for APOE ε4 negative, high hippocampal volume participants; 8.89 years (95% confidence interval 7.56‐12.36) for APOE ε4 positive, high hippocampal volume participants; 8.10 years (95% confidence interval 7.34‐11.08) for APOE ε4 negative, low/medium hippocampal volume participants; and 7.38 (95% confidence interval 6.74‐9.29) years for APOE ε4 positive, low/medium hippocampal volume participants. Conclusions Among patients with clinically diagnosed dementia with Lewy bodies, those with neuroimaging evidence of hippocampal atrophy have shorter survival times. © 2016 International Parkinson and Movement Disorder Society