Individual Study / OBAS

• United States of America

Portland, OR metro area.

• The participants are primarily Caucasian. Two participants are Asian and one participant is Native American.

• Well-controlled, chronic medical conditions common with advanced age, such as hypertension and coronary artery disease are acceptable.

• Age > 84 years
• No subjective complaint of memory impairment compared to others of their own age
• Has not sought assessment for memory or cognitive dysfunction
• Normal memory function defined by an education-adjusted score on the Logical Memory Subscale of the Wechsler Memory Scale-Revised: >8 for 16 or more years of education; > or = 4 for 8-15 years of education; >2 for 0 -7 years of education
• Mini-Mental State Examination score >23
• Blessed Orientation Memory Concentration Test (Telephone Screen) <12
• Functionally independent (ADL= 0)
• Clinical Dementia Rating = 0
• Absence of significant depressive symptoms: CES-D-10 score < 4
• Sufficient vision and hearing to complete all testing
• Sufficient English language skills to complete all testing
• General health status that will not interfere with ability to complete longitudinal study (conditions that will likely lead to this problem are listed below in the study exclusions list)
• Informant available with frequent (at least 1 hour per day 3 days a week) contact with subject to verify functional status.

• Diseases associated with dementia such as Alzheimer disease, ischemic vascular dementia, normal pressure hydrocephalus, or Parkinson disease
• Significant disease of the CNS such as brain tumor, seizure disorder, subdural hematoma, cranial arteritis
• Current (within the last 2 years) alcohol or substance abuse according to DSM-IV criteria
• Major depression, schizophrenia, or other major psychiatric disorder defined by DSM-IV criteria
• Abnormal laboratory values indicating B12 deficiency, thyroid disease, or urinary tract infection (documented chronic bacterial colonization is acceptable)
• Unstable or significantly symptomatic cardiovascular disease such as coronary artery disease with frequent angina, or congestive heart failure with shortness of breath at rest
• Insulin dependent diabetes mellitus
• Active systemic cancer within 5 years of study entry (Gleason Grade <3 prostate cancer, and non-metastatic skin cancers are acceptable)
• Illness that requires >1 visit per month to a clinician
• Progressive vision loss (age-related macular degeneration already beginning to significantly degrade vision)
• Need for oxygen supplementation for adequate function
• Medications: Frequent use of high doses of analgesics; Sedative medications except for those used occasionally for sleep (use limited to no more than twice per week);
• Subjects taking CNS-active medications that have not been on stable doses for at least 2 months including cimetidine, beta-blockers, and selective serotonin reuptake inhibitors; Subjects taking neuroleptics, antiparkinsonian agents, systemic corticosteroids, and narcotic analgesics; in the case where these were used for a self-limited time they must have been discontinued for a period of five half-lives prior to baseline; Subjects will not be excluded if they are taking other over-the counter supplements, but the dose must not be changed during the course of the trial unless medically indicated; the presence and dose of these agents will be recorded; Subjects taking cholinesterase inhibitors; Use of investigational drugs within five half-lives prior to baseline.

• Participants from existing studies

• Dementia Prevention Study