Development of a Database to Investigate Digital and Blood-Based Biomarkers and Their Relationship to Tau and Amyloid PET Imaging in Older Participants Who Are Cognitively Normal (CN), Have Mild Cognitive Impairment (MCI), or Have Mild-to-Moderate AD Dementia

Exclusion Criteria

• •Participants who meet ANY of the following criteria will not be eligible to progress to Visit 1 (Screening):
• •1. Participant is unable to undergo amyloid and tau PET scans due to self-reported pregnancy, sensitivity to ligands being used, poor venous access, contraindication to PET, or planned or recent exposure to ionizing radiation that in combination with the planned administration of amyloid radioligand would result in a cumulative exposure that exceeds recommended local guidelines;
• •2. Participants who have reported or have a known negative amyloid PET scan in the past 6 months;
• •3. Participants with any known contraindication to brain MRI scan;
• •4. Participants with history of stroke or seizures within 1 year of the Pre-Screening Visit;
• •5. Participants with history of cancer within the past 5 years with the exception of non-melanoma skin cancer or prostate cancer in situ;
• •6. Participants with known or suspected alcohol or drug abuse or dependence within 1 year of the Pre- Screening Visit;
• •7. Participants who report any current unstable psychiatric symptoms that could interfere with study procedures or impact study data (e.g., uncontrolled depression);
• •8. Participants who have received any potential disease modifying AD treatment within 6 months prior to the Pre-screening Visit; and
• •9. Participants with known history or self-report to be Human Immunodeficiency Virus (HIV) Positive unless controlled by antiviral medication.
• •1. Participants who, in the opinion of the Site Principal Investigator, have serious or unstable medical conditions that would prohibit their completion of all study procedures and data collection;
• •2. Participants who have serious or unstable medical conditions that would likely preclude their participation in an interventional research trial;
• •3. Participants with self-reported, untreated conditions such as vitamin B12 or folate deficiency or bladder infections that in the opinion of the Site Principal Investigator could contribute to cognitive impairment;
• •4. Participants who have completed cognitive testing within 1 month of Visit 1 (Screening) where the Site Principal Investigator believes the participant's exposure may cause practice effect;
• •5. Participants who have any neurological disorder affecting the central nervous system, other than AD, that may be contributing to cognitive impairment (e.g., Parkinson's disease, other dementias, multiple concussions or seizures) as deemed significant by the Site Principal Investigator;
• •6. Participants with a Geriatric Depression Scale (GDS) score greater than or equal to 8 at Visit 1 (Screening) and is deemed to be clinically significantly depressed by the Site Principal Investigator;
• •7. Participants with a Rey Auditory Verbal Learning Test (RAVLT) t-score of ≥ 1.2 standard deviation above the mean. For non-African Americans, calculate age-sex-education adjusted t-scores. For African American participants, use the MOANS to calculate the age-education adjusted t-scores;
• •8. Participants weighing less than 110 pounds;
• •9. Participants who are direct employees or family members of direct employees of the participating investigators' sites;
• •10. Participants who are direct employees of the Sponsor;
• •11. Participants who, in the opinion of the investigator, are unable to complete cognitive testing due to inadequate visual or auditory acuity; and
• •12. For participants completing the RetiSpec retinal scan: Those with a known history of contraindication or allergy to Tropicamide 1% (pupil dilation drop).
• •Longitudinal Sub-Study Eligibility
• •Participants who meet ANY of the following criteria will not be eligible for entry into the sub-study:
• •1. Those who are enrolled or intend to enroll into a clinical trial for Alzheimer's disease with a potential disease-modifying intervention;
• •2. Participants who have serious or unstable medical conditions that would likely preclude their participation in an interventional research trial;
• •3. Those who intend to use medications outside clinical research studies approved by regulatory authorities to modify Alzheimer's disease pathology.