Inclusion Criteria:

• * Cognitively normal persons, individuals with mild cognitive impairment or dementia who are at least 40 years of age.
• * Willing to undergo health and cognitive assessments, and collection and banking of blood with venipuncture for genetic research, biomarker research, and DNA banking.

Exclusion Criteria:

• * 1. Participants whose diagnosis is unclear and confounded by multiple possible factors are excluded. Participants with diagnoses of non-AD dementias are not excluded.
• 2. Participants whose primary diagnosis is cognitive impairment due to a penetrating or single severe closed head injury, multiple sclerosis, brain tumor, metabolic or toxic encephalopathy, post-infectious (e.g., viral encephalitis, bacterial meningitis), paraneoplastic, primary psychiatric illness, or otherwise not deemed relevant to the intent of the Alzheimer Disease Center program are excluded.
• 3. Procedure specific exclusion criteria also apply but this does not impact the participants ability to be included in the study.