Alzheimer's Disease
Disease Information
The most common form of dementia among older people is Alzheimer's disease (AD), which involves the parts of the brain that control thought, memory, and language.
Alzheimer's disease (AD) is a neurodegenerative disease that slowly kills nerve cells in areas of the brain that are vital to memory and other mental abilities. Patients suffering from the disease experience a progressive loss of mental and physical function. Symptoms include memory loss, delusional thinking, language deterioration, poor judgment, indifferent attitude and agitation.
Causes
Scientists do not yet fully understand what causes AD. There probably is not one single cause, but several factors that affect each person differently. Age is the most important known risk factor for AD. The number of people with the disease doubles every five years beyond age 65. Family history is another risk factor. Scientists also believe that genetic factors may play a role in many AD cases.
Scientists still need to learn a lot more about what causes AD. In addition to genetics and age factors, they are studying environmental factors such as education, nutrition, and viral infections to learn what role they might play in the development of this disease.
Types of Alzheimer's Disease
Scientists have identified two different forms of the disease.
- Early Onset: Early onset, or familial, cases of AD usually occur in patients between the ages of 30 and 60. This type of the disease is rare and accounts for less than 10 percent of total AD cases. Familial AD is hereditary and attributable to mutations on chromosome 21, mutations to the presenilin 1 gene on chromosome 14, or mutations to the presenilin 2 gene on chromosome 1.
- Late Onset: Late onset, or sporadic, cases of AD usually occur in patients 65 and older. This form of the disease is more prevalent than familial AD and affects the majority of AD patients. The role of genes in sporadic AD is not completely understood. Research indicates that genes play a role in the development of AD by affecting factors involved in the formation of amyloid plaques and neurofibrillary tangles or other AD related pathologies in the brain.
Treatment
There is not a readily available cure for Alzheimer's disease, but there are prescription drugs approved by the FDA to treat the cognitive symptoms of the disease. These treatments belong to a class of drugs called acetylcholinesterase inhibitors but only produce modest improvement in AD patients.