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Introduction Dementia is
a brain disorder that seriously affects a person's ability to carry
out daily activities. The most common form of dementia among older
people is Alzheimer's disease, which involves the parts of the brain
that control thought, memory and language. Although scientists are
learning more every day, right now they still do not know what
causes Alzheimer's, and there is no cure.
Scientists think that as many as 4.5 million Americans suffer
from Alzheimer's. The disease usually begins after age 60, and risk
goes up with age. While younger people also may get Alzheimer's, it
is much less common. About 5 percent of men and women ages 65 to 74
have Alzheimer's, and nearly half of those age 85 and older may have
the disease. It is important to note, however, that Alzheimer's is
not a normal part of aging.
Alzheimer's disease is named after Alois Alzheimer, a German
doctor. In 1906, he 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 signs of Alzheimer's disease.
Scientists also have found other brain changes in people with
Alzheimer's. Nerve cells die in areas of the brain that are vital to
memory and other mental abilities. There also are lower levels of
some of the chemicals in the brain that carry messages back and
forth between nerve cells. Alzheimer's disease may impair thinking
and memory by disrupting these messages.
What causes Alzheimer's disease?
Scientists do not yet fully understand what causes Alzheimer's
disease. There probably is not one single cause but several factors
that affect each person differently. Age is the most important known
risk factor. The number of people with the disease doubles every
five years beyond age 65.
Family history is another risk factor. Scientists believe that
genetics may play a role in many cases. For example, familial
Alzheimer's disease, a rare form that usually occurs between the
ages of 30 and 60, is inherited. The more common form is known as
late-onset. It occurs later in life, and no obvious inheritance
pattern is seen. However, several risk-factor genes may interact
with each other to cause the disease. The only risk-factor gene
identified so far for late-onset Alzheimer's is a gene that makes
one form of a protein called apolipoprotein E, or apoE. Everyone has
apoE, which helps carry cholesterol in the blood. It is likely that
other genes also may increase the risk or protect against
Alzheimer's, but they remain to be discovered. The
National Institute on Aging, part
of the National Institutes of Health, is sponsoring the Alzheimer's
Disease Genetics Initiative to recruit families with Alzheimer's to
learn more about risk-factor genes. To participate in this study,
families should contact the National Cell Repository for Alzheimer's
Disease toll-free at 1 (800) 526-2839 or send an e-mail to
alzstudy@iupui.edu.
Scientists still need to learn a lot more about what causes
Alzheimer's. In addition to genetics and apoE, they are studying
education, diet and environment to learn what role they might play
in the development of this disease. Scientists are finding
increasing evidence that some of the risk factors for heart disease
and stroke, such as high blood pressure, high cholesterol and low
levels of the vitamin folate, may predispose people to Alzheimer's.
Evidence for physical, mental and social activities as protective
factors against Alzheimer's is also increasing.
What are the symptoms of Alzheimer's disease?
Alzheimer's begins slowly. At first, the only symptom may be mild
forgetfulness. In this stage, people may have trouble remembering
recent events, activities, or the names of familiar people or
things. They may not be able to solve simple math problems. 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 Alzheimer's or their
family members to seek medical help. For example, people in the
middle stages 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 Alzheimer's may become anxious or aggressive
or wander away from home. Eventually, patients need total care.
How is Alzheimer's disease diagnosed?
An early, accurate diagnosis of Alzheimer's helps patients and
their families plan for the future. It gives them time to discuss
care while the patient can still take part in making decisions.
Early diagnosis will also offer the best chance to treat the
symptoms of the disease.
Today, the only definite way to diagnose Alzheimer's is to find
out whether there are plaques and tangles in brain tissue. To look
at brain tissue, however, doctors must wait until they do an
autopsy, which is an examination of the body done after a person
dies. Therefore, doctors can only make a diagnosis of "possible" or
"probable" Alzheimer's while the person is still alive.
At specialized centers, doctors can
diagnose Alzheimer's correctly up to 90 percent of the time. Doctors
use several tools to diagnose "probable" Alzheimer's, including:
- Questions about the person's general health, past medical
problems and the history of any difficulties the person has
carrying out daily activities.
- Tests of memory, problem-solving, attention, counting and
language.
- Medical tests, such as tests of blood, urine or spinal fluid.
- Brain scans.
Some of these test results help the doctor find 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 symptoms like Alzheimer's. Some of these other
conditions can be treated successfully.
Recently, scientists have focused on a type of memory change
called mild cognitive impairment, which is different from both
Alzheimer's and normal age-related memory change. People with mild
cognitive impairment have ongoing memory problems, but they do not
have other losses like confusion, attention problems and difficulty
with language. Scientists funded by the National Institute on Aging
are studying information collected from the Memory Impairment Study
to learn whether early diagnosis and treatment of mild cognitive
impairment might prevent or slow further memory loss, including the
development of Alzheimer's.
Scientists are finding that damage to parts of the brain involved
in memory, such as the hippocampus, can sometimes be seen on brain
scans before symptoms of the disease occur. The National Institute
on Aging is funding the AD Neuroimaging Initiative, a study that
will find out whether brain scans can diagnose Alzheimer's disease
early. These brain scans and other potential "biomarkers" have the
potential for speeding the testing of drugs for mild cognitive
impairment and Alzheimer's.
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 How is Alzheimer's disease treated?
Alzheimer's 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,
patients live from eight to 10 years after they are diagnosed,
though the disease can last for as many as 20 years.
No treatment can stop Alzheimer's. 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. Another drug, memantine (Namenda), has been approved for
treatment of moderate to severe Alzheimer's. Also, some medicines
may help control behavioral symptoms, 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 Alzheimer's is an active area of
research. Scientists are testing a number of drugs to see if they
prevent Alzheimer's, slow the disease or help reduce symptoms.
There is evidence that inflammation in the brain may contribute
to damage from Alzheimer's. Some scientists believe that drugs such
as nonsteroidal anti-inflammatory drugs might help slow the
progression of the disease, although recent studies of two of these
drugs, rofecoxib (Vioxx) and naproxen (Aleve), have shown that they
did not delay the progression in people who already have the
disease. Now, scientists are studying two other nonsteroidal
anti-inflammatory drugs, celecoxib (Celebrex) and naproxen, to find
out if they can slow the onset of the disease.
Research has shown that vitamin E slows the progress of some
consequences of Alzheimer's by about seven months. Scientists now
are studying vitamin E to learn whether it can prevent or delay
Alzheimer's in patients with mild cognitive impairment.
Recent research suggests that ginkgo biloba may be of some help
in treating symptoms. There is no evidence that ginkgo will cure or
prevent Alzheimer's. Scientists now are trying to find out whether
ginkgo biloba can delay or prevent dementia in older people.
Recent findings from the Women's Health Initiative highlight the
importance of clinical trials, which are studies to find out whether
a treatment is both safe and effective. Earlier studies had
suggested that the hormone replacement therapy that millions of
women take after menopause may be protective against Alzheimer's.
However, the Women's Health Initiative clinical trial found an
increased risk of Alzheimer's in women taking hormones as compared
with those taking an inactive pill. The trial used a commonly
prescribed pill combining estrogens and progesterone. Further
studies on estrogen alone and other hormone preparations, such as
the estrogen patch, continue.
People Alzheimer's and those with mild cognitive
impairment who want to help scientists test possible treatments may
be able to take part in clinical trials. Healthy people also can
help scientists learn more about the brain and Alzheimer's disease.
The National Institute on Aging and the
Food and Drug Administration are
working together to maintain the
Alzheimer's
Disease Clinical Trials Database, which lists clinical trials
sponsored by the federal government and private companies. To find
out more about these studies, contact the Alzheimer's Disease
Education and Referral Center of the National Institute on Aging at
1 (800) 438-4380 or visit
www.alzheimers.org. You also can sign up for
e-mail alerts
on new clinical trials that have been added to the database.
Many of these studies are being done at
Alzheimer's Disease
Centers supported by the National Institute on Aging and located
throughout the United States. These centers carry out a wide range
of research, including studies of the causes, diagnosis, treatment
and management of Alzheimer's. To get a list of these centers,
contact the Alzheimer's Disease Education and Referral Center.
Is there help for caregivers?
Most often, spouses or other family members provide the
day-to-day care for people with Alzheimer's. 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 Alzheimer's disease. 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 Alzheimer's disease. Findings from years of
research have begun to clarify differences between normal
age-related memory changes, mild cognitive impairment and
Alzheimer's. Scientists also have made great progress in defining
the changes that take place in the brain with Alzheimer's, which
allows them to pinpoint possible targets for treatment. These
advances are the foundation for the Alzheimer's Disease Prevention
Initiative of the National Institutes of Health, which is designed
to:
- Understand why Alzheimer's 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
Alzheimer's.
For more information
To learn about support groups, services, research centers,
getting involved in studies and publications about Alzheimer's
disease, contact the following:
Alzheimer's Association
225 N. Michigan Avenue, Suite 1700
Chicago, IL 60611-1676
1 (800) 272-3900
Website: www.alz.org
This nonprofit association supports families and caregivers of
patients with Alzheimer's. Chapters nationwide provide referrals to
local resources and services and sponsor support groups and
educational programs.
Alzheimer's Disease Education and Referral Center
P.O. Box 8250
Silver Spring, MD 20907-8250
1 (800) 438-4380
Website: 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 Alzheimer's.
Publications can be previewed and ordered on the website. Staff
members respond to telephone, e-mail and written requests and make
referrals to local and national resources.
Eldercare Locator
1 (800) 677-1116
Website: www.eldercare.gov
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.
[Alzheimer's Disease
Education and Referral Center]
U.S. Department of Health and Human Services
Public Health Service
National Institutes of Health
National Institute on Aging
NIH Publication No. 03-3431
February 2003 |
