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Alzheimer's Disease Fact Sheet


Introduction

Dementia is a brain disorder that seriously affects a person's ability to carry out daily activities. Alzheimer's disease (AD) is the most common form of dementia among older people. It involves the parts of the brain that control thought, memory, and language. Every day scientists learn more, but right now the causes of AD are still unknown, and there is no cure.

Scientists think that up to 4 million Americans suffer from AD. The disease usually begins after age 60, and risk goes up with age. While younger people also may get AD, it is much less common. About 3 percent of men and women ages 65 to 74 have AD, and nearly half of those age 85 and older may have the disease. It is important to note, however, that AD is not a normal part of aging.

AD is named after Dr. Alois Alzheimer, a German doctor. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness.

He found abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary tangles). Today, these plaques and tangles in the brain are considered hallmarks of AD.

Scientists also have found other brain changes in people with AD. There is a loss of nerve cells in areas of the brain that are vital to memory and other mental abilities. There also are lower levels of chemicals in the brain that carry complex messages back and forth between nerve cells. AD may disrupt normal thinking and memory by blocking these messages between nerve cells.

What Causes AD?

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 5 years beyond age 65.

Family history is another risk factor. Scientists believe that genetics may play a role in many AD cases. For example, familial AD, a rare form of AD that usually occurs between the ages of 30 and 60, can be inherited. However, in the more common form of AD, which occurs later in life, no obvious family pattern is seen. One risk factor for this type of AD is a protein called apolipoprotein E (apoE). Everyone has apoE, which helps carry cholesterol in the blood. The apoE gene has three forms. One seems to protect a person from AD, and another seems to make a person more likely to develop the disease. Other genes that increase the risk of AD or that protect against AD probably remain to be discovered.

Scientists still need to learn a lot more about what causes AD. In addition to genetics and apoE, they are studying education, diet, environment, and viruses to learn what role they might play in the development of this disease.

What Are the Symptoms of AD?

AD begins slowly. At first, the only symptom may be mild forgetfulness. People with AD may have trouble remembering recent events, activities, or the names of familiar people or things. Simple math problems may become hard to solve. Such difficulties may be a bother, but usually they are not serious enough to cause alarm.

However, as the disease goes on, symptoms are more easily noticed and become serious enough to cause people with AD or their family members to seek medical help. For example, people in the later stages of AD may forget how to do simple tasks, like brushing their teeth or combing their hair. They can no longer think clearly. They begin to have problems speaking, understanding, reading, or writing. Later on, people with AD may become anxious or aggressive, or wander away from home. Eventually, patients need total care.

How is AD Diagnosed?

An early, accurate diagnosis of AD helps patients and their families plan for the future.

It gives them time to discuss care options while the patient can still take part in making decisions. Early diagnosis also offers the best chance to treat the symptoms of the disease.

Today, the only definite way to diagnose AD is to find out whether there are plaques and tangles in brain tissue. To look at brain tissue, doctors must wait until they do an autopsy, which is an examination of the body done after a person dies. Therefore, doctors must make a diagnosis of "possible" or "probable" AD.

At specialized centers, doctors can diagnose AD correctly up to 90 percent of the time. Doctors use several tools to diagnose "probable" AD:

  • A complete medical history includes information about the person's general health, past medical problems, and any difficulties the person has carrying out daily activities.
  • Medical tests - such as tests of blood, urine, or spinal fluid - help the doctor find other possible diseases causing the symptoms.
  • Neuropsychological tests measure memory, problem solving, attention, counting, and language.
  • Brain scans allow the doctor to look at a picture of the brain to see if anything does not look normal.

Information from the medical history and test results help the doctor rule out other possible causes of the person's symptoms. For example, thyroid problems, drug reactions, depression, brain tumors, and blood vessel disease in the brain can cause AD-like symptoms. Some of these other conditions can be treated successfully.

Recently, scientists have focused on a type of memory change called mild cognitive impairment (MCI). MCI is different from both AD and normal age-related memory change. People with MCI have ongoing memory problems but do not have other losses like confusion, attention problems, and difficulty with language. Scientists funded by the National Institute on Aging (NIA) are conducting the Memory Impairment Study to learn whether early diagnosis and treatment of MCI might prevent or slow further memory loss, including the development of AD.

How is AD Treated?

AD is a slow disease, starting with mild memory problems and ending with severe brain damage. The course the disease takes and how fast changes occur vary from person to person. On average, AD patients live from 8 to 10 years after they are diagnosed, though the disease can last for as many as 20 years.

No treatment can stop AD. However, for some people in the early and middle stages of the disease, the drugs tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon), or galantamine (Reminyl) may help prevent some symptoms from becoming worse for a limited time. Also, some medicines may help control behavioral symptoms of AD such as sleeplessness, agitation, wandering, anxiety, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.

Developing new treatments for AD is an active area of research. Scientists are testing a number of drugs to see if they prevent AD, slow the disease, or help reduce behavioral symptoms.

Scientists are testing two different types of nonsteroidal anti-inflammatory drugs (NSAIDs) to find out if they slow the disease. There is evidence that inflammation in the brain may contribute to AD damage. Scientists believe that anti-inflammatory drugs such as NSAIDs might help slow the progression of AD. Rofecoxib (Vioxx) and naproxen (Aleve) are two NSAIDs currently being studied.

Research has shown that vitamin E slows the progress of some consequences of AD by about 7 months. Scientists now are studying vitamin E to learn whether it can prevent or delay AD in patients with MCI.

Recent research suggests that ginkgo biloba, an extract made from the leaves of the ginkgo tree, may be of some help in treating AD symptoms. There is no evidence that ginkgo will cure or prevent AD. Scientists now are trying to find out whether ginkgo biloba can delay or prevent dementia in older people.

Research also is under way to see if estrogen reduces the risk of AD or slows the disease. One study showed that estrogen does not slow the progression of already diagnosed disease, but more research is needed to find out if it may play another role. For example, scientists now are trying to find out whether estrogen can prevent AD in women with a family history of the disease.

People with AD and those with MCI who want to help scientists test possible treatments may be able to take part in clinical trials. Clinical trials are studies to find out whether a new treatment is both safe and effective. Healthy people also can help scientists learn more about the brain and AD. The NIA and the Food and Drug Administration (FDA) are working together to maintain the AD Clinical Trials Database, which lists AD clinical trials sponsored by the Federal government and private companies. To find out more about these studies, contact the NIA's Alzheimer's Disease Education and Referral (ADEAR) Center at 1-800-438-4380, or visit the ADEAR Center website at http://www.alzheimers.org. You may want to check regularly to see what new clinical trials have been added to the database.

Many of these studies are being done at NIA-supported Alzheimer's Disease Centers located throughout the United States. These centers carry out a wide range of research, including studies of the causes, diagnosis, treatment, and management of AD. To get a list of these centers, contact the ADEAR Center.

Is There Help for Caregivers?

Most often, spouses or other family members provide the day-to-day care for people with AD. As the disease gets worse, people often need more and more care. This can be hard for caregivers and can affect their physical and mental health, family life, job, and finances.

The Alzheimer's Association has chapters nationwide that provide educational programs and support groups for caregivers and family members of people with AD. For more information, contact the Alzheimer's Association listed at the end of this fact sheet.

Research

Research Scientists have come a long way in their understanding of AD. Findings from years of research have begun to clarify differences between normal age-related memory changes, MCI, and AD. Scientists also have made great progress in defining the changes that take place in the AD brain, which allows them to pinpoint possible targets for treatment. These advances are the foundation for the National Institutes of Health (NIH) Alzheimer's Disease Prevention Initiative, which is designed to:

  • understand why AD occurs and who is at greatest risk of developing it
  • improve the accuracy of diagnosis and the ability to identify those at risk
  • discover, develop, and test new treatments
  • discover treatments for behavioral problems in patients with AD

For More Information

To learn about support groups, services, research centers, and publications about AD, contact the following groups:

Alzheimer's Association
Suite 1100
919 North Michigan Avenue
Chicago, IL 60611-1676
800-272-3900 Web address: http://www.alz.org

This non-profit association supports families and caregivers of patients with AD. Chapters nationwide provide referrals to local resources and services, and sponsor support groups and educational programs.

Alzheimer's Disease Education and Referral (ADEAR) Center
PO Box 8250
Silver Spring, MD 20907-8250
800-438-4380
Web address: http://www.alzheimers.org

This service of the National Institute on Aging is funded by the Federal Government. It offers information and publications on diagnosis, treatment, patient care, caregiver needs, long-term care, education and training, and research related to AD. Staff answer telephone and written requests and make referrals to local and national resources.

Eldercare Locator
800-677-1116
Web address: http://www.aoa.gov/elderpage/locator.html

This service of the Administration on Aging is funded by the Federal Government. It offers information about and referrals to respite care and other home and community services offered by State and Area Agencies on Aging.

U.S DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
National Institutes of Health
National Institute on Aging

NIH Publication No. 01-3431

September 2001