Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills and, eventually even the ability to carry out the simplest tasks of daily living. In most people with Alzheimer’s, symptoms first appear after age 60. Alzheimer’s disease is the most common cause of dementia among older people.

The disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. Her symptoms included memory loss, language problems, and unpredictable behavior. After she died, he examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary tangles).

Plaques and tangles in the brain are two of the main features of Alzheimer’s disease. The third is the loss of connections between nerve cells (neurons) in the brain.

It’s important to know the signs of Alzheimer’s disease. If you know the signs, you can get help right away. Some signs of the disease are listed here:

Early signs

  • finding it hard to remember things
  • asking the same questions over and over
  • having trouble paying bills or solving simple math problems
  • getting lost
  • losing things or putting them in odd places

Later signs

  • forgetting how to brush your teeth or comb your hair
  • being confused about time, people, or places
  • forgetting the names of common things, such as a desk, house, or apple
  • wandering away from home

Mild cognitive impairment

Some older people have a condition called mild cognitive impairment, or MCI. It can be an early sign of Alzheimer’s. But, not everyone with MCI will develop Alzheimer’s disease. People with MCI can still take care of themselves and do their normal activities.

CI memory problems may include:

  • losing things often
  • forgetting to go to events or appointments
  • having more trouble coming up with words than other people the same age.

If you have MCI, it’s important to see your doctor or specialist every 6 to 12 months.

Ask him or her to check for changes in your memory and thinking.

Alzheimer’s disease can be definitively diagnosed only after death, by linking clinical measures with an examination of brain tissue and pathology in an autopsy. But doctors now have several methods and tools to help them determine fairly accurately whether a person who is having memory problems has “possible Alzheimer’s dementia” (dementia may be due to another cause) or “probable Alzheimer’s dementia” (no other cause for dementia can be found).

To diagnose Alzheimer’s, doctors may:

  • Ask questions about overall health, past medical problems, ability to carry out daily activities, and changes in behavior and personality
  • Conduct tests of memory, problem solving, attention, counting, and language
  • Carry out standard medical tests, such as blood and urine tests, to identify other possible causes of the problem
  • Perform brain scans, such as computed tomography (CT) or magnetic resonance imaging (MRI), to distinguish Alzheimer’s from other possible causes for symptoms, like stroke or tumor

These tests may be repeated to give doctors information about how the person’s memory is changing over time.

Early, accurate diagnosis is beneficial for several reasons. It can tell people whether their symptoms are from Alzheimer’s or another cause, such as stroke, tumor, Parkinson’s disease, sleep disturbances, side effects of medications, or other conditions that may be treatable and possibly reversible.

There is no known cure for Alzheimer's disease, but there are treatments that can prevent some symptoms from getting worse for a limited time. Ongoing research offers hope that someday it may be possible to delay the onset of Alzheimer's, slow its progress, or prevent it altogether.

The course of Alzheimer's disease -- which symptoms appear and how quickly changes occur -- varies from person to person. The time from diagnosis to the end of life varies, too. It can be as little as 3 years if the person is over 80 years old when diagnosed, or as long as 10 years or more if the person is younger.

A person with Alzheimer's should be under a doctor's care and may see a neurologist, psychiatrist, family doctor, internist, or geriatrician (a specialist who treats older adults). The doctor can treat the person's physical and behavioral problems and answer the many questions that the person and his or her family may have.

No treatment can stop Alzheimer's disease. However, four drugs are used to treat symptoms of the disease. They may help maintain thinking, memory, and speaking skills and help with some behavioral problems for a limited time. These drugs work by regulating certain chemicals in the brain.

For people with mild or moderate Alzheimer's, donepezil (Aricept), rivastigmine (Exelon), or galantamine (Razadyne) may help prevent some symptoms from becoming worse for a limited time. Donepezil is also approved for symptoms of moderate to severe Alzheimer's. Another drug, memantine (Namenda), is used to treat symptoms of moderate to severe Alzheimer's, although it is also limited in its effects.

All of these drugs have possible side effects, including nausea, vomiting, diarrhea, and loss of appetite. You should report any unusual symptoms to a doctor right away. It is important to follow a doctor's instructions when taking any medication.

Some medicines and other non-drug approaches can help control the behavioral symptoms of Alzheimer's disease. These symptoms include sleeplessness, agitation, wandering, anxiety, anger, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.

Scientists do not yet fully understand what causes Alzheimer's disease. For most people there probably is not one single cause, but several genetic, environmental, and lifestyle factors that affect each person differently. Increasing age is the most important known risk factor for Alzheimer's disease. The number of people with the disease doubles every 5 years beyond age 65.

Family history is another risk factor for Alzheimer's disease. Early-onset familial Alzheimer's disease, a rare form of Alzheimer's that occurs between the ages of 30 and 60, is inherited. It is caused by mutations, or changes, in certain genes.

The more common form of Alzheimer's disease is known as late-onset. It occurs after age 60. No obvious family pattern is seen in most of these cases. But genetic factors appear to increase a person's risk of developing late-onset Alzheimer's.

The increased genetic risk of late-onset Alzheimer's is related in some way to a gene called apolipoprotein E, or APOE. One form of the APOE gene occurs in about 40 percent of all people who develop late-onset Alzheimer's. But many people who get Alzheimer's do not have this form of the gene, and some people with this form of the gene never get Alzheimer's.

Scientists still need to learn a lot more about causes and risk factors. In addition to genetics and studies of pathways in the brain affected by the disease, they are also studying lifestyle factors, such as diet, exercise, and social engagement. Scientists are finding more clues that some health conditions, like heart disease, high blood pressure, diabetes, and obesity, are related to Alzheimer's disease. It's possible that controlling these conditions will reduce the risk of getting Alzheimer's.

Research suggests that these steps might lower the risk of developing Alzheimer's disease:

  • lowering high blood pressure and high cholesterol levels
  • controlling diabetes
  • being physically active
  • eating a healthy diet
  • engaging in activities that stimulate the mind

More studies are being done to see which health and lifestyle factors directly affect the chances of developing Alzheimer's. Many of these factors are known to lower the risk for other diseases and help maintain and improve overall well-being, so they are good to do anyway. Currently, there are no treatments, drugs, or pills that can prevent Alzheimer's disease.

How Do I Find Help?

Consult a doctor when you have concerns about memory loss, thinking skills and behavior changes in yourself or a loved one. It is important for a doctor to determine the cause of memory loss or other symptoms. Treatable conditions that may mimic Alzheimer's disease include depression, drug interaction, thyroid problems, excess alcohol use, symptoms associated with certain vitamins, and dehydration.

An early, accurate diagnosis of Alzheimer's disease helps persons living with the disease and their families plan for the future by providing:

  • Time to discuss care while the person living with Alzheimer's disease can still participate in making decisions.
  • Lessened anxiety about unknown problems.
  • An opportunity to initiate treatment for the symptoms of the disease.
  • More time to plan for the future.

Participating in Clinical Trials

People with Alzheimer’s disease, those with MCI, those with a family history of Alzheimer’s, and healthy people with no memory problems and no family history of the disease may be able to take part in clinical trials. Participants in clinical trials for Alzheimer’s disease help scientists learn about the brain in healthy aging as well as what happens in Alzheimer’s. Results of clinical trials may lead to improved prevention and treatment approaches. Volunteering to participate in clinical trials is one way to help in the fight against Alzheimer’s disease.

The National Institute on Aging (NIA), part of the National Institutes of Health (NIH), leads the Federal Government’s research efforts on Alzheimer’s. NIA-supported Alzheimer’s Disease Centers located throughout the United States conduct many clinical trials and carry out a wide range of research, including studies of the causes, diagnosis, and management of Alzheimer’s. NIA also sponsors the Alzheimer’s Disease Cooperative Study (ADCS), a consortium of leading researchers throughout the U.S. and Canada who conduct clinical trials on promising Alzheimer’s treatments.

Supporting Families and Caregivers

Caring for a person with Alzheimer’s disease can have high physical, emotional, and financial costs. The demands of day-to-day care, changing family roles, and difficult decisions about placement in a care facility can be hard to handle. Researchers have learned much about Alzheimer’s caregiving, and studies are helping to develop new ways to support caregivers.

Becoming well-informed about the disease is one important long-term strategy. Programs that teach families about the various stages of Alzheimer’s and about flexible and practical strategies for dealing with difficult caregiving situations provide vital help to those who care for people with Alzheimer’s.

Developing good coping skills and a strong support network of family and friends also are important ways that caregivers can help themselves handle the stresses of caring for a loved one with Alzheimer’s disease. For example, staying physically active provides physical and emotional benefits.

Some Alzheimer’s caregivers have found that participating in a support group is a critical lifeline. These support groups allow caregivers to find respite, express concerns, share experiences, get tips, and receive emotional comfort. Many organizations, such as those listed in the “For More Information” section, sponsor in-person and online support groups across the country. There are a growing number of groups for people in the early stage of Alzheimer’s and their families. Support networks can be especially valuable when caregivers face the difficult decision of whether and when to place a loved one in a nursing home or assisted living facility.

Review Date: 
April 3, 2012