Changes in certain cognitive measures may "trigger" an in-person assessment, in which participants may change from a categorization of normal or amnestic MCI, to non-amnestic MCI, impaired not MCI, or dementia (i.e., specifically Alzheimer's Disease or another dementia). We estimate that 12% of the study population will trigger over the 4 years of the study and will progress to a more impaired diagnostic category. In addition, a random sample of non-triggered cases (25%) will be selected for an in-person re-assessment during the 4 years of the protocol as a comparison for the trigger group. At the end of the 4-year study period all participants will undergo an in-person evaluation.