This project will focus on the development and testing of efficient, cost effective measures that are specifically designed for use in AD primary prevention trials. The new or improved measures that have been developed will then be evaluated in 650 nondemented subjects enrolled in a simulated Alzheimer's disease prevention trial. Once enrolled, subjects will be followed for four years with annual clinical evaluations and interim six-month phone calls.

Inclusion Criteria:

• 75 years or older.
• Fluent in English or Spanish.
• Stable medical condition for four weeks prior to screening visit.
• Stable medications for four weeks prior to screening visit.
• Either cognitively normal, or mild cognitive impairment. If MCI, the subject's CDR at screening have a global score of 0.5.
• mMMSE score greater than 88 for subjects with at least 8 years education, or greater than 80 for subjects with less than 8 years education, and FCSRT total free plus cued recall score greater than 44 with 3 learning trials.
• Willing to participate in four to five year follow-up study.
• Willing to identify person who can serve as informant.
• At least six years education or work history sufficient to exclude mental retardation

Exclusion Criteria:

• Meets DSM IV criteria for dementia
• History of clinically significant medical illness that would interfere with participation in trial, including active malignancy, myocardial infarction, or cerebrovascular accident within the past year
• Alcohol or substance abuse and/or active major psychiatric disorders
• Concurrent participation in a clinical drug trial
• History of mental retardation