Olfactory Deficits and Donepezil Treatment in Cognitively Impaired Elderly

In this clinical trial, the investigators will evaluate, treat and follow two broad samples of adult patients at New York State Psychiatric Institute/Columbia University Medical Center. Study 1 will include 70 patients with amnestic Mild Cognitive Impairment (MCI). Study 2 will include 100 patients with probable Alzheimer's Disease (AD). Recruitment will be from clinics and/or advertisements. In the protocol, all 170 patients will receive baseline memory and olfactory assessments and are treated with donepezil. Patients will be followed for a total of 1 year. During this time, patients will be monitored closely by the study physician and will receive memory and olfactory assessments at weeks 0, 8, 26, and 52. In addition, an olfactory challenge test will be done at baseline. This project will be of value in the selection of patients with MCI and AD for treatment based on the evaluation of olfaction tests to predict response to donepezil. Since mild cognitive impairment is widespread and Alzheimer's disease represents a major public health problem, this study has considerable public purpose and significance.