Dementia is a condition that affects memory and thinking enough to interfere with normal daily activities. About 3.5 million Americans age 71 years or older have dementia. Some older people may have mild cognitive problems without meeting criteria for dementia. Mild cognitive impairment might affect attention, language, judgment, memory, reading, or writing. It may be noticeable to the individual or to other people, but it does not severely impair activities of daily living. Few studies examine the frequency and course of mild cognitive impairment in older adults.