Dementia is not a disease itself; it is a group of symptoms caused by various diseases and conditions. One of the diseases that is associated with the group of symptoms described as dementia is Alzeimer’s disease. Alzeimer’s disease is estimated to cause 50 to 60 percent of all dementias. (WebMD, 2010) The type of dementia associated with Alzeimer’s disease is a disease of the nervous system. Dementia develops when parts of the brain involved with learning, memory, decision-making, and language are affected by infection or disease, in this case Alzeimer’s disease. People affected with Alzeimer’s related dementia most commonly first exhibit a loss of memory function. A person’s control over their emotions and a loss of inhibitions are usually affected next. As Alzeimer’s advances, brain lesions, called amyloid plaques and tangles, develop. (WebMD, 2010) These brain lesions cause the brain cells to die, resulting in a decreased ability to cope with everyday life.

One current theoretical explanation for dementia due to Alzeimer’s disease involves genetic factors. Much of a person’s risk for Alzeimer’s disease is inherited. One gene that increases the risk of Alzeimer’s dementia is the Apo E gene, a gene that produces the protein apolipoprotein E. (WebMD, 2010) Another theory for the explanation of Alzeimer’s associated dementia is a link between obesity and Alzeimer’s disease. The high insulin levels seen in obese people may mean an increased risk of Alzeimer’s disease and people with diabetes are at high risk for developing the disease.  A more controversial explanation theory is the presence of a link between Alzeimer’s and aluminum. This theory arose when researchers found traces of the metal in the brains of Alzeimer’s patients. Subsequent studies have not been able to confirm the findings. (WebMD, 2010)