Alzheimer's disease is an irreversible, degenerative brain disorder. Symptoms occur gradually. The vast majority of people who have Alzheimer’s are over age 65.
The early symptoms can include loss of recent memory, thinking less clearly, becoming confused easily, faulty judgment and changes in personality. As the disease progresses, people may forget how to do simple tasks, such as dressing themselves or eating with utensils. Most people with Alzheimer's disease eventually become unable to care for themselves.
In the late stages of the disease, people tend to be bedridden and prone to other illnesses and infections.
Specific behaviors—and how long they last—vary greatly from person to person. This makes it difficult to predict how the disease will progress.
On average, people who have Alzheimer's disease live for four to eight years after symptoms become noticeable to others, according to the Alzheimer's Association, although the disease can last for up to 20 years.
New assessment scales are being developed to help doctors track, predict and treat symptoms.
Many healthy people are less able to recall certain kinds of information as they get older. But Alzheimer's disease involves more than simple memory lapses. It also causes difficulties in communicating, learning, thinking and reasoning. And Alzheimer's disease destroys brain cells, which is not a normal part of aging.
Scientists are still looking for the exact cause of Alzheimer's disease. They do know, however, that with Alzheimer's disease, many nerve cells in the brain stop functioning, lose connections with other nerve cells and die. Two abnormal structures in the brain appear to play a part:
Plaques. Smaller than pinheads, plaques consist of beta-amyloid (a type of protein) and various cells. The plaques form in the spaces between nerve cells and disrupt the communication between the cells.
Tangles. These are abnormal collections of twisted protein threads inside nerve cells. When the protein threads wind around one another, the transport system within a cell may collapse and nerve death may result.
Environmental, lifestyle and genetic factors appear to contribute to, or trigger, the process by which plaques and tangles damage the brain.
A variety of tools may be used to help diagnose Alzheimer's disease in people who are having trouble with memory or other mental functions, says the National Institute on Aging. These tools include:
Asking questions about the person's health and history.
A physical exam.
Tests that measure memory, language skills and other abilities related to brain function.
Brain scans (to rule out other conditions, such as strokes or tumors).
Until the early 2000s, the only way to get a conclusive diagnosis was by examining the brain after death to see if telltale markers were there. Scientists now have other tools—such as special lab and imaging tests—that can be used to diagnose the disease more accurately, but the availability of these tests is limited.
6. After diagnosis, can a person continue to live independently?
A person's ability to live independently after a diagnosis of Alzheimer's disease depends on the progression of the disease and the person's remaining abilities for doing tasks such as managing money, taking care of routine chores and driving safely.
A person may be able to live alone or with some help for a while, but over time, care needs will increase and he or she will need to rely on others for more help.