Alzheimer's disease. Conceptual computer artwork of an elderly man with Alzheimer's disease. The fragmentation of the image represents the memory loss and disorientation caused by the condition as it destroys brain cells. The causes of Alzheimer's are poorly understood, but it is associated with the formation of plaques of insoluble protein (amyloid) in the brain, and decreased levels of the neurotransmitter acetylcholine. Aging is the main risk factor. It is incurable, but the symptoms can be treated with drugs to raise acetylcholine levels, such as Aricept, Exelon and Reminyl.