Alzheimer disease


Dementia is a loss of brain function that occurs with certain diseases. Alzheimer disease (AD) is one form of dementia. It affects memory, thinking, and behavior.

Alternative Names

Senile dementia - Alzheimer type (SDAT); SDAT


The exact cause of Alzheimer disease (AD) is not known. Research shows that certain changes in the brain lead to AD developing.

You are more likely to develop AD if you:

The following may also increase the risk:

There are two types of AD:


AD symptoms include difficulty with many areas of mental function, including:

AD usually first appears as forgetfulness.

Mild cognitive impairment (MCI) is the stage between normal forgetfulness due to aging, and the development of AD. People with MCI have mild problems with thinking and memory that do not interfere with daily activities. They are often aware of the forgetfulness. Not everyone with MCI develops AD.

Symptoms of MCI include:

Early symptoms of AD can include:

As AD becomes worse, symptoms are more obvious and interfere with the ability to take care of oneself. Symptoms may include:

People with severe AD can no longer:

Other symptoms that may occur with AD:

Exams and Tests

A skilled health care provider can often diagnose AD with the following steps:

A diagnosis of AD is made when certain symptoms are present, and by making sure other causes of dementia are not present.

Tests may be done to rule out other possible causes of dementia, including:

CT or MRI of the brain may be done to look for other causes of dementia, such as a brain tumor or stroke. Sometimes, a PET scan can be used to rule out AD.

The only way to know for certain that someone has AD is to examine a sample of their brain tissue after death.


There is no cure for AD. The goals of treatment are:

Medicines are used to:

Before using these medicines, ask the provider:

Support Groups

Having AD or caring for a person with the condition may be a challenge. You can ease the stress of illness by seeking support through AD resources. Sharing with others who have common experiences and problems can help you not feel alone.

Outlook (Prognosis)

How quickly AD gets worse is different for each person. If AD develops quickly, it is more likely to worsen quickly.

People with AD often die earlier than normal, although a person may live anywhere from 3 to 20 years after diagnosis.

Families will likely need to plan for their loved one's future care.

The final phase of the disease may last from a few months to several years. During that time, the person becomes totally disabled. Death usually occurs from an infection or organ failure.

When to Contact a Medical Professional

Call the health care provider if:


Although there is no proven way to prevent AD, there are some measures that may help prevent or slow the onset of AD.

These include keeping a low-fat diet and eating foods high in omega-3 fatty acids. Getting physical exercise and staying mentally and socially active also seem to help.


Alzheimer's Association. 2014 Alzheimer's Disease Facts and Figures. Washington, DC: Alzheimer's Association. Available at: Accessed November 5, 2014.

Apostolova LG, DeKosky ST, Cummings JL. Dementias. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 66.

Bayer A. Presentation and clinical management of dementia. In: Fillit HM, Rockwood K, Woodhouse K, eds. Brocklehurst's Textbook of Geriatric Medicine and Gerontology. 7th ed. Philadelphia, PA; 2010:chap 52.

Camicioli R, Rockwood K. Dementia diagnosis. In: Fillit HM, Rockwood K, Woodhouse K, eds. Brocklehurst's Textbook of Geriatric Medicine and Gerontology. 7th ed. Philadelphia, PA; 2010:chap 51.