Inclusion Criteria

1. Participant must be aged 60 years to 85 years, inclusive, and known to have at least one of the

following four risk factors for AD: (1) increased age (65-85 years), (2) positive apolipoprotein-E

ε4 carrier status, (3) positive family history of AD (at least a first-degree relative), or

(4) evidence of abnormal cerebral amyloid by positron emission tomography imaging or

cerebrospinal fluid analysis. Specifically, participants aged 65 to 85 years meet the age criteria,

while participants 60 to 64 years must have at least one of the other risk factors, 2 through 4,

approved by the Medical Monitor prior to enrollment. The risk factor(s) must be known prior to

participation in the study. Note: determination of apolipoprotein-E ε4 carrier status and amyloid

positivity are not part of this study.

2. Participant must be a first-language speaker for the language under investigation by country and

must be resident in that country for 3 years or more.

3. Participant must sign an ICF allowing release of medical records for review by site personnel

and for source data verification in accordance with local requirements.

4. Additional inclusion criterion for the participants with amnestic mild cognitive impairment:

Participant must have amnestic mild cognitive impairment based on the clinical interview and

medical record review, and defined by the following: a memory complaint, objective memory

impairment for age, preserved general cognitive function other than memory, intact functional

activities, not demented, and no evidence of other causes for memory impairment other than

AD.

Exclusion Criteria

1. Participant has a history of dementia or cognitive impairment due to any cause other than

possible AD.

2. Participant has any neurologic disease or conditions known to cause or to be associated with

cognitive impairment other than AD. Conditions include, for example, Parkinson’s disease;

traumatic brain injury with residual neurological deficit; stroke or transient ischemic attack;

seizures (excluding febrile seizures in childhood); hydrocephalus at any time; current liver or

renal insufficiency; human immunodeficiency virus; or significant cardiac, vascular,

pulmonary, gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, psychiatric,

infectious, or metabolic disturbances.

3. Participant has a diagnosis of significant psychiatric illness, as defined by the Diagnostic and

Statistical Manual of Mental Disorders, 4th Edition Text Revision (DSM-IV-TR), including

but not limited to major depressive disorders, anxiety disorders, schizophrenia, or bipolar

disorder.

4. Participant has a history of alcohol or drug dependence or abuse, as defined by DSM-IV-TR

criteria, within the last 5 years.

5. Participant has B12 deficiency, metabolic problems, or nutritional deficiencies (eg, folic acid)

or other disorders that could cause cognitive impairment, including hypothyroidism or

hyperthyroidism, unless well-controlled with no changes in medication and no

hospitalizations related to the condition in the past 6 months. Individuals who are receiving or

have received B12 injections in the past 6 months are excluded.

6. Chronic use of medications known to impair cognition such as sedatives, pain medications, or

anticonvulsants. Additionally, use of such medications within 48 hours or four times the

half-life, whichever is longer, before cognitive assessments is prohibited.

7. Participant has a clinically significant infection (eg, persistent or acute infection, such as

urinary tract infection or upper respiratory infection) within 30 days of study entry.

8. Participant has received an investigational drug (including investigational vaccines) or used an

invasive investigational medical device within 30 days before the start of the study or the first

data-collection time point, or is currently enrolled in an investigational study or clinical trial.

9. Participant has any disability that would prevent completion of study procedures or

assessments (eg, blindness or significant visual impairment, deafness or significant hearing

impairment, non–AD-related speech impairment, or sensory or motor dysfunction).

10. Additional exclusion criterion for the cognitively normal group:

Participant has past or current use of cholinesterase inhibitors or memantine.