September is World Alzheimer’s Month and Sept. 21 is Alzheimer’s Action Day—a day to wear purple and raise awareness of this devastating disease. 

Here are five things to know about Alzheimer’s disease:

1. Alzheimer’s disease is the most common cause of dementia among older people. 

It is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks.  Symptoms usually first appear after the age of 60.  Estimates vary, but experts suggest that as many as 5.1 million Americans may have Alzheimer’s disease. 

2. Microscopic changes in the brain begin long before the first signs of memory loss. 

The brain has 100 billion nerve cells (neurons), each connecting with others to form communication networks.  These groups of cells all have their own jobs—thinking, learning, remembering, sight, hearing and smell.  Scientists believe Alzheimer's disease prevents parts of these cells from working properly.  As the disease spreads, cells lose their ability to do their jobs and eventually die, causing irreversible changes in the brain.

3. The most common symptom of Alzheimer's is difficulty remembering newly learned information. 

 As it advances through the brain, Alzheimer’s disease leads to increasingly severe symptoms, including disorientation, mood and behavior changes, confusion about events, time and place, difficulty speaking, swallowing and walking.

4. Alzheimer's has no current cure, but treatments for symptoms are available and research continues.

Although current Alzheimer's treatments cannot stop the disease from progressing, they can slow the worsening of symptoms and improve the quality of life for both those afflicted with the disease and their caregivers.

5. Alzheimer's is not a normal part of aging. 

Although the greatest known risk factor is increasing age, Alzheimer's is not just a disease of old age. Up to 5 percent of people with the disease have early onset Alzheimer's (also known as younger onset), which often appears when someone is in their 40s or 50s.

For additional information, contact: 

• Alzheimer’s Disease Education and Referral (ADEAR) Center
  P.O. Box 8250
  Silver Spring, MD 20907-8250
  1-800-438-4380 (toll-free)
  www.nia.nih.gov/alzheimers 

• Alzheimer’s Association
  225 N. Michigan Avenue, Floor 17
  Chicago, IL 60601-7633
  1-800-272-3900 (toll-free)
  1-866-403-3073 (TDD/toll-free)
  www.alz.org

• Alzheimer’s Foundation of America
  322 Eighth Avenue, 7th Floor
  New York, NY 10001
  1-866-AFA-8484 (1-866-232-8484; toll-free)
  www.alzfdn.org

Sources: National Institute on Aging:  “Fact Sheet,” Alzheimer’s Association: “What is Alzheimer’s?”