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Alzheimer's
Disease Fact Sheet
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Alzheimer's disease
(AD) is the most common cause of dementia in older people. A
dementia is a medical condition that disrupts the way the brain
works. AD affects the parts of the brain that control thought,
memory, and language. Every day, scientists learn more about
AD, but right now the cause of the disease still is unknown,
and there is no cure. An estimated 4 million people in the United
States suffer from AD.
The disease usually
begins after age 65, and risk of AD goes up with age. While
younger people also may have 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 senile or neuritic 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 changes in the brains of 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 billions of nerve cells. AD may disrupt normal
thinking and memory by blocking these messages between nerve
cells.
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 for these people 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 with AD may forget how to
do simple tasks, like brushing their teeth or combing their
hair. They can no longer think clearly; and 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 may need total care.
Doctors at specialized
centers can diagnose probable AD correctly 80 to 90 percent
of the time. They can find out whether there are plaques and
tangles in the brain only by looking at a piece of brain tissue
under a microscope. It can be painful and risky to remove brain
tissue while a person is alive. Doctors cannot look at the tissue
until they do an autopsy, which is an examination of the body
done after a person dies.
Doctors may say that
a person has "probable" AD. They will make this diagnosis by
finding out more about the person's symptoms. The following
is some of the information the doctor may need to make a diagnosis:
- A Complete
Medical History
The doctor may
ask about the person's general health and past medical problems.
He or she will want to know about any problems the person
has carrying out daily activities. The doctor may want to
speak with the person's family or friends to get more information.
- Basic Medical
Tests
Tests of blood
and urine may be done to help the doctor eliminate other
possible diseases. In some cases, testing a small amount
of spinal fluid also may help. In addition, scientists are
busy trying to develop a test to diagnose AD that will be
easy and accurate.
- Neuropsychological
Tests
These are tests
of memory, problem solving, attention, counting, and language.
They will help the doctor pinpoint specific problems the
person has.
- Brain Scans
The doctor may
want to do a special test, called a brain scan, to take
a picture of the brain. There are several types of brain
scans, including a computerized tomography (CT) scan, a
magnetic resonance imaging (MRI) scan, or a positron emission
tomography (PET) scan. By looking at a picture of the brain,
the doctor will be able to tell if anything does not look
normal. Information from the medical history and any test
results help the doctor rule out other possible causes of
the person's symptoms. For example, thyroid gland 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.
AD is a slow disease,
starting with mild memory problems and ending with severe mental
damage. The course the disease takes and how fast changes occur
vary from person to person. Some people only have the disease
for 5 years, while others may have it 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 drug tacrine (also known as THA or Cognex)
may alleviate some cognitive symptoms. 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.
Scientists are testing
new drugs for AD at many large teaching hospitals and universities.
Some of these drugs have shown promise in easing symptoms in
some patients. People with AD who want to help scientists test
these experimental drugs may be able to take part in clinical
trials. To find out more about these studies, contact the Alzheimer's
Disease Education and Referral (ADEAR) Center at the telephone
number listed at the end of this fact sheet.
People with AD should
go to their doctor regularly. The doctor will check to see how
the disease is progressing and treat any other illnesses that
occur. The doctor and other health professionals also can offer
help and support to patients and their families.
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, jobs, 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.
Scientists at research
centers across the country are trying to learn what causes AD
and how to prevent it. They also are studying how memory loss
happens. They are looking for better ways to diagnose and treat
AD, to improve the abilities of people with the disease, and
to support caregivers.
The major risk factors
for AD are age and family history. Other possible risk factors
include a serious head injury and lower levels of education.
Scientists also are studying additional factors to see if they
may cause the disease. Some of these factors include:
- Genetic (Inherited)
Factors
Scientists believe
that genetic factors may be involved in more than half of
the cases of AD. For example, a protein called apolipoprotein
E (ApoE) may be important. Everyone has ApoE, which helps
carry cholesterol in the blood. However, the function of
ApoE in the brain is less understood. The ApoE gene has
three forms. One form seems to protect a person from AD,
and another form seems to make a person more likely to develop
the disease. Scientists still need to learn a lot more about
ApoE and its role in AD.
- Environmental
Factors
Scientists have
found aluminum, zinc, and other metals in the brain tissue
of people with AD. They are studying these metals to see
if they cause AD or if they build up in the brain as a result
of the disease.
- Viruses
Some scientists
think that a virus may cause AD. They are studying viruses
that might cause the changes seen in the brain tissue of
people with AD.
AD probably is not
caused by any one factor. It is more likely to be several factors
that act differently in each person. For example, genetic factors
alone may not be enough to cause the disease. Other risk factors
may combine with a person's genetic makeup to increase his or
her chance of developing the disease.
Scientists also are
trying to develop a test that can detect or predict AD. If the
onset of the disease could be delayed for even a short time,
the number of people with the disease would drop. Delaying AD
also would make the quality of life better for older people
and lead to savings in health care costs.
Other research is
aimed at helping both patients and caregivers cope with the
patients' loss of abilities and the stress this causes. For
example, researchers are studying ways to manage problem behaviors
in patients, such as wandering and agitation. Still other scientists
are evaluating services and programs for patients and caregivers,
including respite care. Respite care covers a variety of situations
in which someone else cares for the patient for a period of
time, giving family caregivers temporary relief.
To learn about support
groups, services, research centers, and publications about AD,
contact the following groups:
- Alzheimer's
Association
919 N Michigan Avenue, Suite 1000
Chicago, IL 60611-1676
800-272-3900
This non-profit
group supports families and caregivers of AD patients. 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
E-Mail: mailto:"adear@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
respond to telephone and written requests and make referrals
to national- and State-level resources.
- Eldercare
Locator
1112 16th Street NW, Suite 100
Washington, DC 20036
800-677-1116
This service
of the National Association of Area Agencies on Aging provides
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
Published
in August 1995
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