Alzheimer's disease (AD), also called Alzheimer disease or simply Alzheimer's, is the most common cause of dementia. Alzheimer's is a degenerative and terminal disease for which there is no known cure. In its most common form, it afflicts individuals over 65 years old, although a less prevalent early-onset form also exists. It is estimated that 26.6 million people worldwide were afflicted by AD in 2006, which could quadruple by 2050, although estimations vary greatly.

The cause and progression of Alzheimer's disease are not well understood. Research indicates that the disease is associated with plaques and tangles in the brain. No treatment has been found to stop or reverse the disease, and it is not known whether current treatments slow the progression, or simply manage the symptoms. Many preventive measures have been suggested for Alzheimer's disease, but their value is unproven in reducing the course and severity of the disease. Mental stimulation, exercise and a balanced diet are often recommended, both as a possible prevention and as a sensible way of managing the disease.

Because AD cannot be cured and is degenerative, management of the Alzheimer's patient is essential. The role of the main caregiver is often taken by the spouse or a close relative. Caregivers may themselves suffer from stress, over-work, depression, and being physically hit or struck.

The disease course is divided into four stages, with a progressive pattern of cognitive and functional impairment expressed during each stage.

As a result of the prevalence of the disease, many notable people have contracted it. Well-known examples are former United States President Ronald Reagan and Irish writer Iris Murdoch, both of whom have scientific articles on how their cognitive capacities deteriorated with the disease.Other cases include the retired footballer Ferenc Puskas, the former British Prime Minister Harold Wilson, the actress Rita Hayworth,the actor Charlton Heston,and the novelist Terry Pratchett.

Alzheimers has also been portrayed in films such as: Iris (2001),(based on John Bayley's memoir of his wife Iris Murdoch);The Notebook (2004), (based on Nicholas Sparks' 1996 novel of the same name); Thanmathra (2005); Memories of Tomorrow (Ashita no Kioku) (2006),(based on Hiroshi Ogiwara's novel of the same name); and Away from her (2006), (based on Alice Munro's short story The bear came over the mountain). Documentaries on AD include Malcolm and Barbara: A Love Story (1999) and Malcolm and Barbara: Love’s Farewell (2007), both featuring Malcolm Pointon. In The Cider House Rules the affliction of a character with Alzheimer's is mistaken as alcoholism.

Source : www.wikipedia.org