Napping, Sleep, Cognitive Decline and Risk of Alzheimer's Disease

Inclusion Criteria: * ≥65 years old * Memory complaints verified by an informant * Clinical diagnosis of mild cognitive impairment (MCI) or mild Alzheimer's Disease * General cognitive performance sufficiently persevered such that a diagnosis of Alzheimer's disease cannot be made by the site physician * No evidence (CT or MRI scans within 12 months prior to screening) of infection, infarction, or other focal lesions and no clinical symptoms suggestive of intervening neurological disease * Adequate visual and auditory acuity to allow neuropsychological testing * Meets International Classification of Sleep Disorders-2nd edition (ICSD-2) criteria for insomnia or circadian rhythm disorders, or shows actigraphy evidence of sleep disturbances and excessive napping Exclusion Criteria: * Any major neurologic disease other than suspected incipient Alzheimer's disease, such as Parkinson's disease, multi-infarct dementia, multiple sclerosis, seizure disorder, Huntington's disease, brain tumor or history of significant head trauma * Any comorbid psychiatric conditions or severe personality disorder within the past 2 years (by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), such as major depression, bipolar disorder, schizophrenia and other psychotic features * Any uncontrolled medical conditions or systemic illness that might lead to difficulty complying with the study protocol * History of alcohol or substance abuse within the past 2 years * Any inadequately treated primary or secondary sleep disorder (due to medical conditions) that might confound the association