African-Americans (AAs) have an increased prevalence of both Alzheimer's disease (AD) and vascular risk factors for AD such as diabetes and hypertension when compared to whites. However, in a recent community based study of non-demented elderly, black race was associated with higher amyloid burden after adjusting for vascular risk factors, suggesting the presence of additional physiological differences on AD-risk by race in the early stages of the disease. The purpose of this study is to test whether poor slow wave sleep (SWS) quantity (SWS duration) and quality (slow wave activity, SWA) is one of these physiological factors. To test these hypotheses, the investigators will perform community outreach in churches and community-based organizations in Brooklyn and other NYC boroughs with which we have created substantial ties in recent years. In consultation with community stakeholders, the investigators will recruit 150 cognitively normal AA elderly (age 60-75) and 60 age, sex, BMI, income and education matched non-Hispanic whites from the same geographical areas. Investigators will first perform a medical and cognitive evaluation (Visit 1). Participants will then undergo 2 nights of home sleep monitoring using an unattended device to exclude OSA, followed by 7 days of actigraphy with a sleep log to record sleep duration. Both devices will be returned by mail. Subjects with reported total sleep time (TST) between 5 and 10 hours and absence of moderate to severe OSA will be invited to perform a 2-night nocturnal polysomnography (NPSG) (Nights 1-2) and a PiB-PET MR scan (Visit 2).

Inclusion Criteria:

• Male and female subjects with normal cognition and ages 60 to 75.
• Within normal limits on neurological and psychiatric examinations. All subjects enrolled will have a CDR=0.
• An informed family member or life-partner (preferably bed-partner) will be interviewed over the phone or on the first or second visit to confirm the reliability of the subject interview. A study partner is preferably a spouse, close friend, or relative.
• Self-identified as African-American Black or non-Hispanic white.
• All subjects must sign the Alzheimer's Disease Center consent form

Exclusion Criteria:

• History of brain tumor, MRI evidence of brain damage or brain disease including significant trauma, hydrocephalus, seizures, mental retardation or other serious neurological disorder (e.g. Parkinson's disease or other movement disorders).

• Significant history of alcoholism based off of the CAGE questionnaire (>2) or drug abuse.

• History of psychiatric illness (e.g., schizophrenia, bipolar or PTSD)

• Lifelong depression and anxiety will be allowed as long as there has been no active depressive episode within the last two years.

• Geriatric Depression Scale (short form)>6.

• Insulin dependent diabetes.

• Evidence of clinically relevant cardiac, pulmonary, endocrine or hematological conditions based off of the PI's discretion.

• Physical impairment of such severity as to adversely affect the validity of psychological testing.

• Any prosthetic devices (e.g., pacemaker or surgical clips) that constitutes a hazard for MRI imaging.

• Medications affecting cognition or SWS:

  • Narcotic analgesics.
  • Chronic use of medications with anticholinergic activity.
  • Anti-Parkinsonian medications (carbidopa/levodopa, amantadine, bromocriptine, pergolide, selegiline).
  • Others: amphetamines, amphetamine-like compounds, appetite suppressants, phenothiazines, reserpine, buspirone, clonidine, disulfiram, guanethidine, MAO inhibitors, theophylline, tricyclic antidepressants, gabapentin, pregabalin, trazodone, cholinesterase inhibitors, memantine.

• Chronic use of antidepressants are allowed.

• History of a first-degree family member with early onset (age <60 years) dementia.

• Short sleepers (< 5 hours a day) and long sleepers (> 10 hours a day).

• OSA (defined as AHI4%>15 and AHI4%>5 with Epworth≥10)

• Self-identified as US-born Caribbean Black, Caribbean-born Black or African-born Black.

210 cognitively normal elderly (Clinical Dementia Rating [CDR]=0), self-identified as African-American (AA) or non-Hispanic white (NHW), ages 60 to 75 years, with English as their primary language

Subjects will have the option to allow their leftover blood and DNA samples to be banked indefinitely for future research related to studies on early diagnosis of Alzheimer's, disease and/or mechanism of neurodegeneration. After the study is completed, the de-identified, archived data will be transmitted to and stored at the CBH Biorepository, under the supervision of Dr. Osorio, for use by other researchers including those outside of the study. Permission to transmit data to the CBH Biorepository will be included in the ICF. During the conduct of the study, an individual participant can choose to withdraw consent to have biological specimens stored for future research. However, withdrawal of consent with regard to biosample storage will not be possible after the study is completed. When the study is completed, access to study data and/or samples will be provided through the CBH Biorepository.