The overall goal of this project is to establish and validate biomarkers associated with the risk and progression of late onset Alzheimer's disease, mild cognitive impairment and cognitive decline. The investigators will use baseline and longitudinal measurements of plasma amyloid beta-40 and amyloid beta-42 to investigate the risk of developing mild cognitive impairment and late onset Alzheimer's disease, as well as the rates of cognitive decline and Alzheimer's disease progression. The driving hypothesis of the study is that amyloid beta in the brain as measured by positron emission tomography positivity is associated with the onset of cognitive decline associated with late onset Alzheimer's disease.

This project is a sub-study of the Washington Heights-Inwood Community Aging Project, which is a multidisciplinary, epidemiological study of Alzheimer's disease and related neurodegenerative disorders. We will obtain positron emission tomography scans and simultaneous x-ray computed tomography scans using Florbetaben from Bayer on a selection of ongoing participants who will be selected on the basis of change in plasma levels of amyloid beta over time. Approximately 200 participants will receive scans beginning in 2009 and in the 2010-2012 assessment wave and then again in a 2014-2015 assessment wave. Our intention is to examine whether uptake of Florbetaben in the brain is associated with decline in cognition over the 10 years prior to the PET scan.

Inclusion Criteria:

• Current Washington Heights-Inwood Community Aging Project (WHICAP) participant Age 65 or older Residing in the community of Washington-Heights/Inwood/Hamilton Heights
• Is able to provide informed consent, understand the information provided on the purpose and conduct of the trial and exhibits adequate visual, auditory and communication capabilities to enable compliance with study procedures. This includes performing the psychometric testing and being able to lie down flat in the Positron Emission Tomography (PET) scanner
• Possesses a general health that permits adequate compliance with all study procedures.
• Informed consent has been signed and dated (with time) by the subject and/or the subject's caregiver (for probable Alzheimer's Disease (AD) patients)

Exclusion Criteria:

• Has any contraindication to PET, such as claustrophobia, or inability to lie flat for half an hour as determined by the onsite radiologist performing the scan
• Current, past, or anticipated exposure to radiation, which may include being badged for radiation exposure in the workplace or participation in nuclear medicine procedures, including research protocols in the last year
• Significant active physical illness particularly those that may affect the brain including blood dyscrasias, lymphomas, hypersplenism, endocrinopathies, renal failure or chronic obstructive lung disease, autonomic neuropathies, peripheral vascular disease, low hemoglobin and malignancy
• Scheduled for surgery and/or another invasive procedure within the time period of up to 24 hours following scan
• Allergic to the tracer or any of its constituents and/or has a history of severe allergic reactions to drugs or allergens (e.g. patients with allergic asthma)
• Critically ill and/or medically unstable and whose clinical course within the observation period is unpredictable, e.g. participants with 14 days of myocardial infarction or stroke, unstable participants with previous surgery (within 7 days), participants with advanced heart insufficiency (New York Heart Association (NYHA) stage IV), or participants with acute renal failure.
• Has received any contrast material (X-ray, Magnetic Resonance Imaging (MRI)), or radiopharmaceuticals within 48 hours prior to the application of the Investigational Medicinal Product (IMP) or for whom application of such a substance is planned for 24 hours following IMP administration