Andrew R. Frank, MD, Alzheimer’s Disease Center, Mayo Clinic College of Medicine, Rochester, MN, U.S.A.
Ronald C. Petersen, MD, PhD, Alzheimer’s Disease Center, Mayo Clinic College of Medicine, Rochester, MN, U.S.A.

Mild Cognitive Impairment (MCI) describes a state of abnormal cognitive functioning that is insufficient to warrant a diagnosis of dementia. While dementia requires that activities of daily functioning be compromised due to cognitive symptomology, the diagnosis of MCI can be made earlier, in the absence of such functional impairment. In MCI, the patient must present with cognitive complaints (or someone who knows the patient well must present them on the patient's behalf), and these complaints must be corroborated by abnormalities on standardized cognitive testing. The diagnosis of MCI alerts the clinician to a higher risk of future development of dementia and provides an ideal target population that may benefit the most from “disease-modifying” cognitive therapies currently in development.
Key words: mild cognitive impairment, MCI, Alzheimer’s disease, dementia, early diagnosis, treatment.