Pre-Clinical (Alzheimers) Diagnosis PCD = Optimum Outcomes OO

Prospective observational study participants age 50-75 years are identified who are currently (\<1 month) taking or will soon (within 3 months) start taking study medications of interest thru their own physician. Prospective observational study participants are explained how persons can be cognitively normal but at high risk for developing clinical ALZ, and that this risk can be prospectively identified. They are advised that there is some rationale that medications they are or will soon be taking may have a protective effect in delaying the onset of ALZ, and that protective effect can be monitored. They are asked if they would like to participate in a protocol that monitors their prospective risk for developing ALZ short term, and whether certain of their prescribed medications may have a protective effect. Those who are accepting to be participants are then enrolled in the study. Enrollees are tested for risk factors for having pre-clinical ALZ. Individuals identified as being at risk at baseline are followed at 6 month intervals for a 24 month period using psychometric testing and functional neuroimaging. Their maintenance of cognitive stability or cognitive decline is monitored while under the care of their PMD and while taking medications of interest.