Memory Impairment Study (Mild Cognitive Impairment Study)

Inclusion Criteria: * Memory complaints and memory difficulties which are verified by an informant. * Abnormal memory function documented by scoring below the education adjusted cutoff on the Logical Memory II subscale (Delayed Paragraph Recall) from the Wechsler Memory Scale - Revised (the maximum score is 25): a) less than or equal to 8 for 16 or more years of education, b) less than or equal to 4 for 8-15 years of education, c) less than or equal to 2 for 0-7 years of education. * Mini-Mental Exam score between 24 and 30 (inclusive) (Exceptions may be made for subjects with less than 8 years of education at the discretion of the project director.). * Clinical Dementia Rating = 0.5. Memory Box score must be at least 0.5. * General cognition and functional performance sufficiently preserved such that a diagnosis of Alzheimer's disease cannot be made by the site physician at the time of the screening visit. * No significant cerebrovascular disease: Modified Hachinski score of less than or equal to 4. * Age between 55 and 90 (inclusive). * Permitted medications stable for at least 1 month prior to screening. In particular: a) Subjects may take stable doses of antidepressants lacking significant anticholinergic side effects (if they are not currently depressed and do not have a history of major depression within the past 2 years). b) Estrogen replacement therapy is permissible. c) Ginkgo biloba is permissible, but discouraged. * Hamilton Depression rating scale score of less t…