Alzheimer’s disease is the most common form of dementia (mental deterioration of memory and thought processes) among the elderly. It is estimated that 4.5 million Americans over the age of 65 are affected with this condition. After the age of 65, the incidence of the disease doubles every five (5) years and, by age 85, it will affect nearly half of the population.

Alzheimer’s disease causes irreversible changes in the nerve cells of certain vulnerable areas of the brain. It is characterized by nerve-cell loss, abnormal tangles within nerve cells and deficiencies of several chemicals, which are essential for the transmission of nerve messages.

The disorder leads to behavioral and personality changes, forgetfulness, confusion, inability to learn new material, paranoia and motor activity problems. Language difficulties also are common in people with Alzheimer’s disease. The disease typically progresses to the stage where it is difficult for the patient to be understood by others or to understand others, and in the final stages, the patient is bedridden. Although nearly half of those over 85 may have Alzheimer’s disease, it is not a ‘normal’ part of aging.

The cause of Alzheimer’s disease has yet to be determined, but there are five theories that warrant further investigation:

Chemical Theories

Chemical Deficiencies. One of the ways in which brain cells communicate with one another is through chemicals called neurotransmitters. Studies of Alzheimer’s diseased brains have uncovered diminished levels of various neurotransmitters that are thought to influence intellectual functioning and behavior.

Toxic Chemical Excesses. Increased deposits of aluminum have been found in Alzheimer’s disease brains.

Genetic Theory

Researchers have linked late-onset Alzheimer’s to the inheritance of a gene that directs production of apolipoprotein (ApoE). In early-onset Alzheimer’s, researchers identified a mutation on chromosome 14, which accounts for 10 percent of Alzheimer’s cases. Additionally, a mutation was found on chromosomes 1 and 21.

Autoimmune Theory

The body’s immune system, which protects against potentially harmful invaders, may erroneously begin to attack its own tissues, producing antibodies to its own essential cells.

Slow Virus Theory

A slow-acting virus has been identified as a cause of some brain disorders that closely resemble Alzheimer’s.

Blood Vessel Theory

Defects in blood vessels supplying blood to the brain are being studied as a possible cause of Alzheimer’s.

The chances of getting Alzheimer’s disease increases with age and it usually occurs after the age of 65, after which the chances of getting the disease double every five years. There are only two definite factors that increase the risk for Alzheimer’s disease before age 65: a family history of dementia or Alzheimer’s, and Down syndrome.