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:
As the disease progresses, people may also: