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Attention Deficit Hyperactivity Disorder (ADD/ADHD)
Alzheimer's Disease
Antidepressants
Anxiety
Asperger's Syndrome
Autism
Bereavement/Grief
Bipolar Disorder
Compulsive Gambling
Coping with Chronic Illness
Child Behavior Disorders
Children Mental Health
Dementia
Depression
Developmental Disabilities
Dual Diagnosis
Eating Disorders
Learning Disorders
Memory
Mental Health
Obsessive-Compulsive Disorder
Panic Disorder
Phobias
Postpartum Depression
Post-Traumatic Stress Disorder
Prader-Willi Syndrome
Schizophrenia
Seasonal Affective Disorder
Suicide
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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 (AD), which initially
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, and connections between nerve cells are disrupted. 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.
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, early-onset 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 in most families.
However, several risk factor genes may interact with each other and with
non-genetic factors 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. Only about 15 percent of people have the form that increases
the risk of AD. It is likely that other genes also may increase the risk
of AD or protect against AD, but they 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, 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 also increase the risk of AD.
Evidence for physical, mental, and social activities as protective factors
against AD is also increasing.
What Are the Symptoms of AD?
AD begins slowly. At first, the only symptom
may be mild forgetfulness, which can be confused with age-related
memory change. Most people with mild forgetfulness do not have AD. In
the early stage of AD, 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. Forgetfulness begins to interfere with daily activities.
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 can fail to recognize familiar people and places. 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 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, however, doctors usually 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 ability to carry 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
Sometimes 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.
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 some people may live with AD 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, which is still
available but no longer actively marketed by the manufacturer), donepezil
(Aricept), rivastigmine (Exelon), or galantamine (Razadyne, previously
known as Reminyl) may help prevent some symptoms from becoming worse
for a limited time. Another drug, memantine (Namenda), has been approved
to treat moderate to severe AD, although it also is limited in its effects.
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.
New Areas of Research
The National Institute on Aging (NIA), part of
the National Institutes of Health (NIH), is the lead Federal
agency for AD research. NIA-supported scientists are testing a number
of drugs to see if they prevent AD, slow the disease, or help reduce
symptoms. Researchers undertake clinical trials to learn whether treatments
that appear promising in observational and animal studies actually are
safe and effective in people. Some ideas that seem promising turn out
to have little or no benefit when they are carefully studied in a clinical
trial.
Neuroimaging. 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. An NIA public-private partnership—the AD Neuroimaging Initiative (ADNI)—is a large
study that will determine whether magnetic resonance imaging (MRI) and
positron emission tomography (PET) scans, or other imaging or biological
markers, can see early AD changes or measure disease progression. The
project is designed to help speed clinical trials and find new ways to
determine the effectiveness of treatments. For more information on ADNI,
call the NIA’s Alzheimer’s Disease Education and Referral
(ADEAR) Center at 1-800-438-4380, or visit www.alzheimers.nia.nih.gov.
AD Genetics. The NIA is sponsoring the
AD Genetics Study to learn more about risk factor genes for late onset
AD. To participate in this study, families with two or more living
siblings diagnosed with AD should contact the National Cell Repository
for AD toll-free at 1-800-526-2839. Information may also be requested
through the study’s website: http://ncrad.iu.edu.
Mild Cognitive Impairment. During the past several years, 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 such as confusion, attention problems, and difficulty
with language. The NIA-funded Memory Impairment Study compared donepezil,
vitamin E, or placebo in participants with MCI to see whether the drugs
might delay or prevent progression to AD. The study found that the group
with MCI taking donepezil were at reduced risk of progressing to AD for
the first 18 months of a 3-year study, when compared with their counterparts
on placebo. The reduced risk of progressing from MCI to a diagnosis of
AD among participants on donepezil disappeared after 18 months, and by
the end of the study, the probability of progressing to AD was the same
in the two groups. Vitamin E had no effect at any time point in the study
when compared with placebo.
Inflammation. There is evidence that inflammation in the brain may contribute
to AD damage. Some studies have suggested that drugs such as nonsteroidal
anti-inflammatory drugs (NSAIDs) might help slow the progression of AD,
but clinical trials thus far have not demonstrated a benefit from these
drugs. A clinical trial studying two of these drugs, rofecoxib (Vioxx)
and naproxen (Aleve) showed that they did not delay the progression of
AD in people who already have the disease. Another trial, testing whether
the NSAIDs celecoxib (Celebrex) and naproxen could prevent AD in healthy
older people at risk of the disease was suspended due to concerns over
possible cardiovascular risk. Researchers are continuing to look for
ways to test how other anti-inflammatory drugs might affect the development
or progression of AD.
Antioxidants. Several years ago, a clinical
trial showed that vitamin E slowed the progress of some consequences
of AD by about 7 months. Additional studies are investigating whether
antioxidants—vitamins E and C—can
slow AD. Another clinical trial is examining whether vitamin E and/or
selenium supplements can prevent AD or cognitive decline, and additional
studies on other antioxidants are ongoing or being planned, including
a study of the antioxidant treatments—vitamins E, C, alpha-lipoic
acid, and coenzyme Q—in patients with mild to moderate AD.
Ginkgo biloba. Early studies suggested that extracts from the leaves
of the ginkgo biloba tree may be of some help in treating AD symptoms.
There is no evidence yet that ginkgo biloba will cure or prevent AD,
but scientists now are trying to find out in a clinical trial whether
ginkgo biloba can delay cognitive decline or prevent dementia in older
people.
Estrogen. Some studies have suggested that estrogen used by women to
treat the symptoms of menopause also protects the brain. Experts also
wondered whether using estrogen could reduce the risk of AD or slow the
disease. Clinical trials to test estrogen, however, have not shown that
estrogen can slow the progression of already diagnosed AD. And one study
found that women over the age of 65 who used estrogen with a progestin
were at greater risk of dementia, including AD, and that older women
using only estrogen could also increase their chance of developing dementia.
Scientists believe that more research is needed to find out if estrogen
may play some role in AD. They would like to know whether starting estrogen
therapy around the time of menopause, rather than at age 65 or older,
will protect memory or prevent AD.
Participating in Clinical Trials
People with AD,
those with MCI, or those with a family history of AD, 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 maintains 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
ADEAR Center at 1-800-438-4380 or visit the ADEAR Center
website at www.nia.nih.gov/Alzheimers/ResearchInformation/ClinicalTrials.
You also can sign up for e-mail alerts on new clinical
trials as they are added to the database. Additional clinical
trials information is available at www.clinicaltrials.gov.
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.
Advancing Our Understanding
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 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.
Is There Help for Caregivers?
Most often, spouses and 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. Contact information for the Alzheimer’s Association
is listed at the end of this fact sheet.
For More Information
To learn about support groups,
services, research centers, getting involved in studies,
and publications about AD, contact the following:
Alzheimer’s Disease
Education and Referral (ADEAR) Center
P.O. Box 8250
Silver Spring, MD 20907-8250
1-800-438-4380
www.alzheimers.nia.nih.gov
This service of the NIA 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,
e-mail, and written requests and make referrals to local and national
resources.
Alzheimer’s Association
225 N. Michigan Avenue, Suite 1700
Chicago, IL 60611-7633
1-800-272-3900
www.alz.org
This nonprofit association supports families and caregivers
of patients with AD and funds research. Chapters nationwide provide referrals
to local resources and services, and sponsor support groups and educational
programs.
Eldercare Locator
800-677-1116
www.eldercare.gov
This service of the Administration on Aging, funded by the
Federal Government, provides information 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
July 2006
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