Investigation Into Delay to Diagnosis of Alzheimer's Disease With Exelon (InDDEx)

Inclusion Criteria: * Are aged 55-85 years, inclusive. Subjects older than 85 years may be eligible to participate, with approval of the designated study medical monitor. * Are male or female without child-bearing potential (i.e., surgically sterilized \[via bilateral tubal ligation,bilateral oophorectomy, or hysterectomy\], at least one year postmenopausal, or using adequate birth control). * Are cooperative, able to ingest oral medication, and willing to complete all aspects of the study. * Will provide written informed consent prior to their participation in the study. * Show evidence of mild cognitive impairment (MCI) by meeting all of the following criteria: Global CDR score = 0.5, NYU Delayed Paragraph Recall less than 9, 17-item HAM-D score less than 13, and HAM-D Item 1 (depressed mood) score =1. * Have a friend or family member who is willing to participate in the study as an informant. The informant must see the subject at least once a week for several hours and be available to accompany the subject to the screening and baseline visits, and at a minimum, be accessible by telephone for other scheduled visits. Exclusion Criteria: * Advanced, severe, and unstable disease of any type that may interfere with primary and secondary variable evaluations including any medical condition that could be expected to progress, recur, or change to such an extent that it may bias the assessment of the clinical or mental status of the subject to a significant degree or put the sub…