DefinitionMulti-infarct dementia (MID) is a form of dementia caused by a series of small strokes.Dementia is a loss of brain function that occurs with certain diseases. It affects memory, thinking, language, judgment, and behavior.Alternative NamesMID; Dementia - vascular; Dementia - poststrokeCauses, incidence, and risk factorsMulti-infarct dementia (MID) is the second most common cause of dementia (after Alzheimer's disease) in people over age 65. MID affects men more often than women. The disorder usually affects people between ages 55 and 75.MID is caused by a series of small strokes.A stroke is an interruption in or blockage of the blood supply to any part of the brain. A stroke is sometimes called an infarct. "Multi-infarct" means that many areas in the brain have been injured due to