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

Memory impairment, as well as problems with language, decision-making ability, judgment, and personality, are necessary features for the diagnosis.

Age and family history are risk factors for AD.

• As you get older, your risk of developing AD goes up. However, developing Alzheimer's disease is not a part of normal aging.

• Having a close blood relative, such as a brother, sister, or parent who developed AD increases your risk.

• Having certain combination of genes for proteins that appear to be abnormal in Alzheimer's disease also increases your risk.

Other risk factors that are not as well proven include:

• Longstanding high blood pressure

• History of head trauma

• Female gender

There are two types of AD -- early onset and late onset