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 (AD), 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 AD, and there is no cure.
Scientists think that as many as 4.5 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 5 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 signs of AD.
Scientists also have found other brain changes in people with AD. 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. AD may impair thinking and memory
by disrupting these messages.
Back to Top
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, is inherited. The more common form
of AD 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 AD, is a gene that makes one form of a protein called
apolipoprotein E (apoE). Everyone has apoE, which helps carry cholesterol in the
blood. It is likely that other genes also may increase the risk of AD or protect
against AD, but they remain to be discovered. The National Institute on Aging
(NIA), part of the National Institutes of Health, is sponsoring the AD Genetics
Initiative to recruit families with AD to learn more about risk factor genes. To
participate in this study, families should contact the National Cell Repository
for AD 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 AD. 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 AD. Evidence for physical, mental, and
social activities as protective factors against AD is also increasing.
Back to Top
What Are the Symptoms of AD?
AD 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 AD or their family members to seek medical
help. For example, people in the middle 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, under-standing, reading, or
writing. Later on, people with AD may become anxious or aggressive, or wander
away from home. Eventually, patients need total care.
Back to Top
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 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 AD is to find out whether there are
plaques and tangles in brain tissue. To look at brain tissue, how-ever, 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" AD while the person is still alive.
At specialized centers, doctors can diagnose AD correctly up to 90 percent of
the time. Doctors use several tools to diagnose "probable" AD,
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, and
- 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 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), which is different from both AD and normal
age-related memory change. People with MCI have ongoing memory problems, but
they do not have other losses like confusion, attention problems, and difficulty
with language. Scientists funded by the NIA
are studying information collected from 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.
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 NIA will be funding the AD Neuroimaging Initiative, a
study that will find out whether brain scans can diagnose AD early. These brain
scans and other potential "biomarkers" have the potential for speeding
the testing of drugs for MCI and AD.
Back to Top
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. Another drug, memantine (Namenda), has
been approved for treatment of moderate to severe AD. 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 symptoms.
There is evidence that inflammation in the brain may contribute to AD damage.
Some scientists believe that drugs such as nonsteroidal anti-inflammatory drugs
(NSAIDs) might help slow the progression of AD, although recent studies of two
of these drugs, rofecoxib (Vioxx) and naproxen (Aleve), have shown that they did
not delay the progression of AD in people who already have the disease. Now,
scientists are studying the NSAIDs 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 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 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.
Recent findings from the Women's Health Initiative
(WHI) 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 AD. However, the WHI clinical trial found an increased risk
of AD in women taking hormones as compared with those taking an inactive pill.
The trial used a commonly pre-scribed pill combining estrogens and progesterone.
Further studies on estrogen alone and other hormone preparations, such as the
estrogen patch, continue.
People with AD and those with MCI 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 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 Web site at 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 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.
Back to Top
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.
Back to Top
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.
Back to Top
For More Information
To learn about support groups, services, research centers, getting involved
in studies, and publications about AD, 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 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
P.O. Box 8250
Silver Spring, MD 20907-8250
1-800-438-4380
Website: www.alzheimers.org
|
This service of the NIA is funded by the Federal
Government (of US). It offers
information and publications on diagnosis, treatment, patient care, caregiver
needs, long-term care, education and training, and research related to AD.
Publications can be previewed and ordered on the Web site. Staff answer
telephone, e-mail, and written requests and make referrals to local and national
resources. |
|
|
(Original
source/ courtesy :
National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov
)
Next
article... Cancer
facts for people over 50
