In Vivo cortical tau in Parkinson's disease using 18F-AV-1451 positron emission tomography

Background: Alzheimer's disease copathology is common in PD at autopsy. In non-PD subjects with mild cognitive impairment, tau depositions can be detected using 18F-AV-1451 PET. We hypothesized that 18F-AV-1451 PET would show tau aggregation in PD with mild cognitive impairment and correlate with cognitive dysfunction. Objectives: To describe tau aggregation in PD patients. Methods: Twenty-six PD patients and 23 controls had 18F-AV-1451 PET and neuropsychological assessment to detect mild cognitive impairment. Results: Nine PD patients (35%) were identified with mild cognitive impairment. Regional analyses showed no significant differences between groups. Voxel-wise analyses showed no correlation with cognitive domain z-scores within patients. One patient with mild cognitive impairment was estimated Braak tau stage 5; all other patients were stage 0. Conclusion: Our results indicate that tau pathology, as detected by 18F-AV-1451, is uncommon in PD with mild cognitive impairment and shows no significant correlation with cognitive dysfunction at this stage.