Dementia is the loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning for at least six months. The most common symptom is short-term memory loss, or forgetting what has happened minutes to days before. Poor judgment, difficulty with language, and a change in personality are other symptoms which may be present. Usually striking older persons, Alzheimer's disease can attack in the middle years as well. Victims suffer a slowly declining ability to remember and loss of intellectual abilities.
Physical disability follows as the disease progresses.
The disease was first described in 1906 by Alois Alzheimer, a German neurologist whose middle-aged patient developed memory problems, then severe dementia, and died at age 51. Much about the disease remains a mystery today. There currently is no known cause or cure. Senility is a less preferred term for dementia, as it implies that confusion in an older person is a normal part of aging. Dementia is an abnormality at any age.