ALZHEIMER'S DISEASE

DEFINITION

Alzheimer's (pronounced ALTS-hih-merz) disease (AD) is the most common form of dementia (pronounced dih-MEN-sha). Dementia is a disease of the nervous system characterized by loss of certain mental abilities. This loss is severe enough to interfere with normal activities and lasts at least six months. AD is not present at birth but usually develops during old age. It is marked by a decline in mental functions such as memory, reasoning, and the ability to plan.

DESCRIPTION

A person with AD usually has a gradual decline in mental functions. The first stages include a slight loss in memory, such as the inability to remember the names of people or objects. As the disease develops, a person loses the ability to carry out familiar tasks, to reason, and to exercise judgment. Moods, personality, and ability to communicate may also be affected.

People with AD typically die within eight years of their diagnosis. Some individuals may die within a year of diagnosis, others may live as long as twenty years. AD is the fourth leading cause of death among adults in the United States after heart disease, cancer, and stroke.

Between two and four million Americans have AD. That number is expected to reach fourteen million by the middle of the twenty-first century. The reason for this growth is that the U.S. population as a whole is aging (there are more older people than younger people).

One form of AD, called early-onset AD, affects people in their forties and fifties. But the majority of AD patients are older than sixty-five. About 3 percent of those between ages sixty-five and seventy-four have the disease compared to 19 percent of those between ages seventy-five and eighty-four, and 47 percent of those over the age of eighty-four.

CAUSES

The causes of AD are currently not known. Research has produced some strong leads, however, and made possible the development of some promising experimental treatments. This research has been based largely on autopsies of people who have died from AD. These autopsies show that brain cells responsible for learning, reasoning, and memory have been damaged. They have become clogged with two kinds of abnormal structures known as neurofibrillary (pronounced noor-o-FIB-ruhl-ary) tangles and senile plaques.

No one knows how these structures cause AD, but researchers have some theories. They think the structures keep brain cells from functioning normally, which prevents the transmission of brain signals from one cell to another.

This discovery has led to the development of one class of drugs for the treatment of AD. These drugs increase the amount of neurotransmitters produced in the brain. Neurotransmitters are chemicals that carry signals between brain cells. The first two drugs of this kind were approved for use by the U.S. Food and Drug Administration (FDA) in January 1998.

What triggers the formation of tangles and plaques is not known. But researchers are pursuing some possible leads. First, inflammation in the brain may be a factor. A class of drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs) may prevent inflammation and reduce the risk of AD.

Free radicals are another factor in the formation of tangles and plaques. Free radicals are very active chemicals that form in the brain and damage brain cells. Chemicals known as antioxidants react with and destroy free radicals. Vitamin E is a naturally occurring antioxidant.

Genetic factors seem to be important in the development of AD. Scientists have discovered certain gene defects that appear to be related to the disease. They have found that mutations (changes) in certain genes are connected with some forms of AD. However, research in this area is at a very early stage. Little information that can be used for treatment of the disease has been uncovered.

In spite of how little is known about the causes of AD, a number of risk factors have been identified. The most obvious of these factors is age. The older a person is, the more likely he or she will be to develop AD. Another risk factor is heredity. People whose family members have had AD, Down's syndrome (see down's syndrome entry), or Parkinson's disease (see Parkinson's disease entry) are more likely to develop Alzheimer's disease than those whose families do not have this history. People who have hypothyroidism (reduced levels of thyroid in the blood) or have experienced head injuries are also at relatively high risk for AD.

Environmental factors have sometimes been proposed as possible causes for AD. For example, the ingestion of aluminum was once thought to be a possible factor in the disease. So far, scientific studies have not been able to confirm the role of any environmental factor in causing AD.

SYMPTOMS

The earliest symptom of Alzheimer's disease is memory loss. Older people often worry that they may have AD because they forget more easily. But memory loss by itself is not an indication that a person has Alzheimer's disease. Some memory loss is a natural part of growing old.

With AD patients, however, memory loss is progressive and, eventually, so serious that they cannot function normally. In the early stages, memory loss may simply mean that the person has forgotten where he or she left the

Diseased brain tissue from an Alzheimer's patient showing senile plaques, seen as darker spots surrounded by lighter halos. (Photograph by

Cecil Fox/Science Source

. Reproduced by permission of the

National Audubon Society Collection/Photo Researchers, Inc.

)

car keys. Over time, the problem becomes so serious that he or she can no longer remember where the car is parked or how to drive it.

As AD progresses, other symptoms appear. Patients can no longer perform routine tasks, like tying shoes or eating. Many patients develop sleep disorders or become confused or disturbed in the evening. These symptoms are sometimes referred to as "sunsetting." In the final stages of the disease, patients have problems eating, communicating with others, and controlling their bladder or bowels.

Other forms of mental disorders can cause any of these symptoms. In fact, about 20 percent of those who are first suspected of having AD turn out to have some other disorder. For that reason, it is essential that a person who experiences any of the symptoms discussed see a doctor for a thorough examination.

DIAGNOSIS

Diagnosis of AD is difficult. Its symptoms are similar to those of other diseases and to those of the normal aging process. For example, loss of memory and depression (see depressive disorder entry) are symptoms of AD, but they are also typical changes that take place as a person gets older.

The only way to be absolutely sure that a person has AD is to perform an autopsy of the brain after death. The autopsy will reveal tangles and plaques that characterize AD. But this method of diagnosis is of no value to a living person.

The main approach used in diagnosing AD is to rule out other disease possibilities. To do so, a doctor uses three methods: physical examination, medical history, and a variety of tests. A physical examination is used to make sure the patient is not suffering from some other medical problem, such as an infection or a mild stroke (see stroke entry). A medical history reveals changes in the patient's behavior. It also includes questions about drugs the patient is taking and other factors that may account for AD-like symptoms. Blood and urine tests, brain scans, and other tests are used to find out if other medical conditions exist that are causing the patient's abnormal behavior.

TREATMENT

There is currently no cure and virtually no medical treatment for Alzheimer's disease. Steps can be taken, however, to make an AD patient more comfortable and to protect him or her from potential dangers posed by the disease. Both physical and emotional support can be provided for the patients who are able to do less and less for themselves.

Caregivers also need assistance. Looking after a person with AD can be discouraging and exhausting. The caregiver needs support to prevent anger, despair, and burnout. Provisions also need to be made for the financial and legal problems that arise as an AD patient is less able to think and plan clearly.

Drugs

The two drugs currently approved for use with AD patients are tacrine (pronounced tak-REEN, trade name Cognex) and donepezil (pronounced do-NEP-uh-zil) hydrochloride (trade name Aricept). Both are neurotransmitters, which increase the ability of brain cells to communicate with each other. In this way, they provide some help in improving a person's ability to think and to perform normal daily activities.

Some communities now offer full-time assisted living centers that cater exclusively to Alzheimer's patients. (Reproduced by

permission of AP/Wide World Photos

)

Tacrine has limited effects on patients in the early stages of AD. While it may delay their admission to a nursing homes by a few months, it is quite expensive and has side effects such as nausea, vomiting, diarrhea, stomach pain, indigestion, and skin rash. Donepezil has two advantages over tacrine: it has fewer side effects and has to be taken only once a day rather than three times a day.

Doctors sometimes prescribe other drugs for AD patients. Several preliminary studies have been made on older women who take the hormone estrogen, which is used to prevent osteoporosis (pronounced OSS-tee-o-puh-ROS-sis; see osteoporosis entry), or weakening of the bones. These studies show that women who take estrogen have lower rates of AD, and that those who do develop AD have slower disease progression and less severe symptoms.

Other early studies show promise in delaying the onset and even the risk of developing AD. The regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the risk of developing AD. Two antioxidants, selegiline and vitamin E, are also thought to delay the onset (beginning) of AD in some people.

Care and Safety of Individuals with Alzheimer's

As the course of AD develops, individuals require more and more care. At first, the problems are relatively simple. Perhaps they lose the ability to select appropriate clothing or comb their hair. Gradually, however, they may not be able to eat, wash, or otherwise take care of themselves.

Ensuring that people with AD eat properly is one problem. Sometimes they may simply not feel hungry or forget how to prepare foods for themselves. In advanced stages of the disease, they may have difficulty in swallowing, which means they ultimately will require the use of a feeding tube.

Eventually, many people with AD become incontinent, that is, they lose control of their bowels and bladder. Problems with incontinence are among the most difficult for family members to deal with, often convincing the family to have the AD patient moved to a nursing home where regular, professional care is available.

If a person with AD remains in the home, they should be provided with a calm, non-threatening environment. Regular exercise is also important. Professional help may be necessary to deal with emotional problems, such as anxiety, depression, and hallucinations.

AD patients must also be protected from a variety of physical hazards. They usually can no longer take long walks by themselves or drive a car. Safety devices such as grab bars in the bathroom, bed rails on the bed, and wider door openings may be needed. Electrical appliances may have to be unplugged when not in use, and the hot water heater thermostat adjusted to prevent the individual from being burned.

Care for the Caregiver

Family members and others who care for a person with AD have a difficult and stressful job that becomes even harder over time. It is not unusual for caregivers to develop feelings of anger, resentment, guilt, and hopelessness. Depression is a common problem among caregivers.

For many caregivers, the most helpful way of dealing with these feelings is a support group. Support groups consist of other AD caregivers and professional counselors. Caregivers have an opportunity to discuss their thoughts and feelings with others in the same situation. Contact numbers of AD support groups can be obtained from the Alzheimer's Association and from local social service agencies, the patient's physician, or drug companies that supply medications used to treat AD.

Outside Help, Nursing Homes, and Government Assistance

The problems of caring for an AD patient often become too much for family members. In such cases, a variety of outside care is usually available. For example, some local community agencies will bring a hot meal to the patient's home each day. Some adult day-care businesses exist where the patient can spend the day under professional supervision.

Eventually, temporary outside help may not be enough. In such cases, the family may decide to move the patient to a nursing home. This decision is usually extremely hard for both the patient and the family. It can also be very expensive. In addition, the most suitable home for the patient may be located at some distance from the family home, making regular visits difficult.

Several federal governmental programs can help with the cost of care for an AD patient. These include Social Security Disability, Medicare, and Supplemental Security income. These programs do not pay for long-term nursing home stays, but they may help with the cost of care, medication, and other expenses. Information about these programs can be obtained from local Social Security and Medicare offices.

Nursing home care can also be paid for through a variety of private insurance programs. In general, these programs tend to be expensive and are not available to many people with limited incomes.

Alternative Treatment

Ginkgo extract has been suggested as a possible treatment for AD patients. Some people think the herb may help relieve the symptoms of dementia. A natural product called acetylcarnitine (pronounced uh-setl-KAR-nuh-teen) has also been proposed as a method for improving the function of brain cells. At present, there is little scientific evidence for the effectiveness of either product. Other nutritional supplements, such as vitamin B₁₂, and folic acid have been recommended for the maintenance of good mental health.

PROGNOSIS

Alzheimer's is sometimes the immediate and direct cause of death. More often, patients die from conditions that result from their generally poor and deteriorating health. Pneumonia, cancer (see cancer entry), stroke, and heart disease (see heart attack and atherosclerosis entries) are the most common of these conditions. On average, people with AD live eight years beyond their diagnosis. Some die as soon as a year after diagnosis, while others survive up to twenty years.

PREVENTION

There is currently no approved method for preventing Alzheimer's disease. There is some hope that some of the drugs mentioned, such as estrogen, NSAIDs, and vitamin E, may be useful. Additional research is being conducted to provide more information.

FOR MORE INFORMATION

Books

Gillick, Muriel R. Tangled Minds: Understanding Alzheimer's Disease and Other Dementias. New York: E. P. Dutton, 1998.

Gray-Davidson, Frena. The Alzheimer's Sourcebook for Caregivers: A Practical Guide for Getting Through the Day. Los Angeles, CA: Lowell House, 1996.

Larkin, Marilynn. When Someone You Love Has Alzheimer's: What You Must Know, What You Can Do, What You Should Expect. New York: Dell Publishing, 1995.

Nelson, James Lindemann, and Hilde Lindemann Nelson. Alzheimer's: Answers to Hard Questions for Families. San Diego, CA: Main Street Books, 1997.

Powell, Lenore S., with Katie Courtice. Alzheimer's Disease: A Guide for Families. Reading, MA: Addison-Wesley Publishing Company, 1993.

Williams, Carol Lynch. If I Forget, You Remember. New York: Delacorte Press, 1998.

Organizations

Alzheimer Association. 919 North Michigan Avenue, Suite 1000, Chicago, IL 60611. (800) 272–3900. (312) 335–8882. http://www.alz.org.

National Institute of Aging. Alzheimer's Education and Referral Center. (800) 438–4380.

Web sites

Alzheimers.com [Online] http://www.alzheimers.com (accessed on June 15, 1999).