Dementia is a loss of brain function that occurs with certain diseases. Alzheimer disease (AD) is the most common form of dementia. It affects memory, thinking, and behavior.
Senile dementia - Alzheimer type (SDAT); SDAT; Dementia - Alzheimer
The exact cause of Alzheimer disease is not known. Research shows that certain changes in the brain lead to Alzheimer disease.
You are more likely to develop Alzheimer disease if you:
Are older -- Developing Alzheimer disease is not a part of normal aging.
Have a close relative, such as a brother, sister, or parent with Alzheimer disease.
Have certain genes linked to Alzheimer disease.
The following may also increase the risk:
Having heart and blood vessel problems due to high cholesterol
History of head trauma
There are two types of Alzheimer disease:
Early onset Alzheimer disease -- Symptoms appear before age 60. This type is much less common than late onset. It tends to get worse quickly. Early onset disease can run in families. Several genes have been identified.
Late onset Alzheimer disease -- This is the most common type. It occurs in people age 60 and older. It may run in some families, but the role of genes is less clear.
Alzheimer disease symptoms include difficulty with many areas of mental function, including:
Emotional behavior or personality
Thinking and judgment (cognitive skills)
Alzheimer disease usually first appears as forgetfulness.
Mild cognitive impairment (MCI) is the stage between normal forgetfulness due to aging, and the development of Alzheimer disease. 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 Alzheimer disease.
Symptoms of MCI include:
Difficulty performing more than one task at a time
Difficulty solving problems
Forgetting recent events or conversations
Taking longer to perform more difficult activities
Early symptoms of Alzheimer disease can include:
Difficulty performing tasks that take some thought, but used to come easily, such as balancing a checkbook, playing complex games (bridge), and learning new information or routines
Getting lost on familiar routes
Language problems, such as trouble remembering the names of familiar objects
Losing interest in things previously enjoyed and being in a flat mood
Personality changes and loss of social skills
As Alzheimer disease becomes worse, symptoms are more obvious and interfere with the ability to take care of oneself. Symptoms may include:
Change in sleep patterns, often waking up at night
Delusions, depression, and agitation
Difficulty doing basic tasks, such as preparing meals, choosing proper clothing, and driving
Difficulty reading or writing
Forgetting details about current events
Forgetting events in one's life history and losing self-awareness
Having Alzheimer disease or caring for a person with the condition may be a challenge. You can ease the stress of illness by seeking support through Alzheimer disease resources. Sharing with others who have common experiences and problems can help you not feel alone.
How quickly Alzheimer disease gets worse is different for each person. If Alzheimer disease develops quickly, it is more likely to worsen quickly.
People with Alzheimer disease 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 provider if:
Alzheimer disease symptoms develop or a person has a sudden change in mental status
The condition of a person with Alzheimer disease gets worse
You are unable to care for a person with Alzheimer disease at home
Although there is no proven way to prevent Alzheimer disease, there are some measures that may help prevent or slow the onset of Alzheimer disease:
Stay on a low-fat diet and eat foods high in omega-3 fatty acids.
Get plenty of exercise.
Stay mentally and socially active.
Wear a helmet during risky activities to prevent brain injury.
Knopman DS. Alzheimer disease and other dementias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 402.
Peterson R, Graff-Radford J. Alzheimer disease and other dementias. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; 2016:chap 95.
Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.