Frequently Asked Questions About Alzheimer's Disease

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 Alzheimer's disease, and there is no cure.

Alzheimer's disease 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 that he identified in his patient’s brain are considered signs of Alzheimer's disease. Scientists also have found other brain changes in people with Alzheimer's disease. 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. Alzheimer's disease may impair thinking and memory by disrupting these messages.
There are currently 5.4 million Americans with Alzheimer's disease. About 13 percent of men and women 65 and older have Alzheimer's disease, and nearly half of those age 85 and older have the disease.
On average, Alzheimer's disease patients live from 8 to 10 years after they are diagnosed, though the disease can last for as many as 20 years.
The cause of the steady and relentless loss of brain cells in Alzheimer's disease is unknown. Theories of the cause include a slow virus, a genetic predisposition, environmental toxins, chemical imbalance in the brain, and auto-immunity.
Alzheimer's strikes rich and poor alike, men and woman, and people of all ethnic groups. The majority of people who are diagnosed with Alzheimer's are 65 and older. Because people are living longer, the age group with highest prevalence is the 85 and over.

Early Onset Alzheimer's is rare and affects individuals in their forties, fifties and early sixties.
Alzheimer's disease 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 Alzheimer's disease. In the early stage of Alzheimer's disease, 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 disease or their family members to seek medical help. Forgetfulness begins to interfere with daily activities. People in the middle stages of Alzheimer's disease 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 Alzheimer's disease may become anxious or aggressive or wander away from home. Eventually, patients need total care.
It used to be said that the diagnosis of Alzheimer's disease could only be made at autopsy. We now know that if a person has a thorough evaluation by a dementia specialist, the diagnosis can be made with a very high degree of accuracy. There is no single test to diagnose Alzheimer's. A comprehensive evaluation should include the following components:

  • History - a thorough medical history must be obtained from the caregiver and the patient 
  • Medical tests - such as tests of blood, or urine to rule out other medical conditions 
  • Brain scans - An MRI is preferable but a CT scan is very good for those who cannot have an MRI. Sometimes a physician will also order a newer scan called a PET scan to help differentiate the specific type of dementia. 
  • Cognitive testing - cognitive testing assesses various areas of cognitive function including, visuospatial, language, short term memory, delayed recall, attention, abstract thinking, executive function, orientation and more. 

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 Alzheimer's disease-like symptoms. Some of these other conditions can be treated successfully.
An early diagnosis of Alzheimer's disease helps patients and their families plan for the future. It gives them time to discuss care options while the patient can still take part in making decisions. Early diagnosis also offers the best chance to treat the symptoms of the disease.

Some causes of dementia are reversible, so it is important to get diagnosed as soon as possible in case the memory problems can be treated.
The term "dementia" is not a disease. Dementia is an umbrella term for disorders where the mental functions break down, causing confusion, disorientation and memory loss. There may also be trouble with language or completing tasks. Dementia is caused by many conditions. Some conditions that cause dementia can be reversed, and others cannot. The two most common forms of dementia in older people are Alzheimer's disease and vascular dementia.

Reversible causes of dementia include vitamin B12 deficiency, poor nutrition, side effects of medications, thyroid problems, untreated infections, depression, sleep apnea and normal pressure hydrocephalus. Medical conditions like these can become serious and should be treated by a doctor as soon as possible.
Alzheimer's is not part of the normal aging process and, therefore, is not a normal event at the end of life. However, as people age, they tend to experience changes in the speed of recall; the information is there, but, with age, it may take longer to call it up. The following examples will illustrate some of the differences between changes due to normal aging and those due to Alzheimer's, especially in the more advanced stages of the disease.
Multi-infarct dementia is the most common type of vascular dementia and is caused by a series of small strokes which affects the brain's blood supply and results in the death of brain tissue. The location in the brain where the small strokes occur determines the seriousness of the problem and the symptoms that arise. Symptoms that begin suddenly may be a sign of this kind of dementia. People with multi-infarct dementia are likely to show signs of improvement or remain stable for long periods of time, then quickly develop new symptoms if more strokes occur. In many people with multi-infarct dementia, high blood pressure is to blame. One of the most important reasons for controlling high blood pressure is to prevent strokes.
During the past several years, scientists have focused on a type of memory change called mild cognitive impairment (MCI). MCI is different from both Alzheimer's disease and normal age-related memory change. People with MCI have ongoing memory problems but do not have other losses like confusion, attention problems, and difficulty with language.
The "early onset form" that has been found in less than 5% of Alzheimer's disease patients usually affects people younger than 50 and is caused by inheritance of mutant forms of certain genes. In addition, changes in other genes my increase or decrease an individual's risk of developing Alzheimer's. Therefore, family history may hint towards the risk of becoming affected by the disease.
There are some preventive measures individuals can do to possibly reduce their risk of developing Alzheimer's disease. Some of the preventive measures include physical exercise, mental exercises, no smoking, maintaining a healthy diet, taking supplements (antioxidants and vitamins A, B, C, and E also lower risk of dementia) and generally following the recommendations for reducing the risk of cardiovascular disease.

Alzheimer's Treatment

No treatment can stop Alzheimer's disease. However, for some people in the early and middle stages of the disease, the drugs donepezil (Aricept®), rivastigmine (Exelon®), or galantamine (Razadyne®, help slow the progression of the disease. Another drug, memantine (Namenda®) can be combined with one of these three to moderate to severe Alzheimer's disease, although it also is limited in its effects.

Also, some medicines may help control behavioral symptoms of Alzheimer's disease such as sleeplessness, agitation, wandering, anxiety, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.
The National Institute on Aging (NIA), part of the National Institutes of Health (NIH), is the lead Federal agency for Alzheimer's disease research. NIA-supported scientists are testing a number of drugs to see if they prevent Alzheimer's disease, slow the disease, or help reduce symptoms. Some ideas that seem promising turn out to have little or no benefit when they are carefully studied in a clinical trial. Researchers undertake clinical trials to learn whether treatments that appear promising in observational and animal studies actually are safe and effective in people.

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 Alzheimer's disease 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 (Aricept), vitamin E, or placebo in participants with MCI to see whether the drugs might delay or prevent progression to Alzheimer's disease. The study found that the group with MCI taking the drug donepezil were at reduced risk of progressing to Alzheimer's disease 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 Alzheimer's disease among participants on donepezil disappeared after 18 months, and by the end of the study, the probability of progressing to Alzheimer's disease was the same in the two groups. Vitamin E had no effect at any time point in the study when compared with placebo.

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 Alzheimer's disease 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 Alzheimer's disease changes or measure disease progression. The project is designed to help speed clinical trials and find new ways to determine the effectiveness of treatments.

Alzheimer's disease Genetics. The NIA is sponsoring the Alzheimer's disease Genetics Study to learn more about risk factor genes for late onset Alzheimer's disease. To participate in this study, families with two or more living siblings diagnosed with Alzheimer's disease should contact the National Cell Repository for Alzheimer's disease (NCRAD) toll-free at 1-800-526-2839. Information may also be requested through the study’s website:

Inflammation. There is evidence that inflammation in the brain may contribute to Alzheimer's disease damage. Some studies have suggested that drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs) might help slow the progression of Alzheimer's disease, 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 Alzheimer's disease in people who already have the disease. Another trial, testing whether the NSAIDs celecoxib (Celebrex) and naproxen could prevent Alzheimer's disease in healthy older people at risk of the disease, has been suspended. However, investigators are continuing to follow the participants and are examining data regarding possible cardiovascular risk. Researchers are continuing to look for ways to test how other anti-inflammatory drugs might affect the development or progression of Alzheimer's disease.

Antioxidants. Several years ago, a clinical trial showed that vitamin E slowed the progress of some consequences of Alzheimer's disease by about 7 months. Additional studies are investigating whether antioxidants—vitamins E and C—can slow Alzheimer's disease. Another clinical trial is examining whether vitamin E and/or selenium supplements can prevent Alzheimer's disease or cognitive decline, and additional studies on other antioxidants are ongoing or being planned.

Ginkgo biloba. Early studies suggested that extracts from the leaves of the ginkgo biloba tree may be of some help in treating Alzheimer's disease symptoms. There is no evidence yet that ginkgo biloba will cure or prevent Alzheimer's disease, 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 Alzheimer's disease or slow the disease. Clinical trials to test estrogen, however, have not shown that estrogen can slow the progression of already diagnosed Alzheimer's disease. One study found that women over the age of 65 who used estrogen with a progestin were at greater risk of dementia, including Alzheimer's disease, 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 Alzheimer's disease. 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 Alzheimer's disease.
People with Alzheimer's disease, those with MCI, or those with a family history of Alzheimer's disease, 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 NIA maintains the Alzheimer's disease Clinical Trials Database, which lists Alzheimer's disease clinical trials sponsored by the Federal government and private companies.

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

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 Alzheimer's disease.

The NIA also supports the Alzheimer's Disease Cooperative Study (ADCS), a consortium of researchers at 109 sites in the U.S. and Canada conducting large-scale clinical trials of new approaches to treating and preventing Alzheimer's disease. The ADCS is based at the University of California, San Diego.