Alzheimer's disease is the most common form of dementia. Dementia is a term that is used to describe a group of brain disorders. These brain disorders cause memory loss and make it harder to carry out daily tasks. Alzheimer's involves the parts of the brain that control thought, memory, and language. The disease affects the brain in different ways. One effect is that a key brain chemical is lost. It is called acetylcholine. In part, this loss can contribute to some of the symptoms of Alzheimer's.
The cause of Alzheimer's is not yet known. Age is the main known risk factor.
Compare the signs of what could be normal aging with the signs of Alzheimer's:
| Normal Aging | Early Signs of Alzheimer's |
| Forgetting the names of people you rarely see | Forgetting the names of people close to you |
| Briefly forgetting part of an experience | Forgetting a recent experience |
| Occasionally not being able to find something |
Not being able to find important things |
| Mood changes because of an appropriate cause | Having unpredictable mood changes |
| Changes in your interests | Decreased interest in outside activities |