18F-AV-1451 PET Imaging in Participants Enrolled in the LEARN Study

Approximately 50 participants enrolled in the LEARN study (NCT02488720) will be enrolled in the LEARN-Tau study. The study designed to evaluate the imaging characteristics of 18F-AV-1451 in participants enrolled in the LEARN study and to expand the safety database of 18F-AV-1451. The study will run in parallel to the LEARN study. In this study, participants will undergo up to four (4) 18F-AV-1451 PET scans over a 4.5 year period. Imaging visits will occur at the throughout the participant\'s participation in the LEARN study (corresponding to LEARN Visit 1, between Visit 4 and 6, Visit 8, and Visit 11). The LEARN-Tau study will (1) look at change in the amount of tau protein in the brain over time, measured by the 18F-AV-1451 PET scan, (2) see if tau protein in the brain of older individuals is associated with memory problems and (3) evaluate the safety of 18F-AV-1451 and any side effects that might be associated with it. Site investigators, participants, and study partners will not be informed of the results of the 18F-AV-1451 PET scan results as they relate to the study; however, any findings that may be of potential medical concern will be provided for appropriate follow-up.