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:
- Being female
- 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.