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Alzheimer's disease is the most common cause of dementia and accounts for 50%-75% of all cases. It destroys brain cells and nerves disrupting the transmitters which carry messages in the brain, particularly those responsible for storing memories. Alzheimer's disease was first described by Alois Alzheimer in 1906.
During the course of Alzheimer's disease, nerve cells die in particular regions of the brain. The brain shrinks as gaps develop in the temporal lobe and hippocampus, which are responsible for storing and retrieving new information. This in turn affects people's ability to remember, speak, think and make decisions. The production of certain chemicals in the brain, such as acetylcholine is also affected. It is not known what causes nerve cells to die but there are characteristic appearances of the brain after death. In particular, 'tangles' and 'plaques' made from protein fragments are observed under the microscope in damaged areas of brain. This confirms the diagnosis of Alzheimer's disease.
Typically, Alzheimer's disease begins with lapses of memory, difficulty in finding the right words for everyday objects or mood swings. As Alzheimer's progresses, the person may:
- Routinely forget recent events, names and faces and have difficulty in understanding what is being said
- Become confused when handling money or driving a car
- Undergo personality changes, appearing to no longer care about those around them
- Experience mood swings and burst into tears for no apparent reason, or become convinced that someone is trying to harm them
As the disease progresses, people may also:
- Adopt unsettling behaviour like getting up in the middle of the night or wander off and become lost
- Lose their inhibitions and sense of suitable behaviour, undress in public or make inappropriate sexual advances.