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Alzheimers
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.
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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.
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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.
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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.
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
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
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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
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
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
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
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