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Alzheimer's Disease

What is Alzheimer’s disease?
 Alzheimer’s disease is a progressive disease that damages nerve cells (neurons) in parts of the brain, especially:

  • The hippocampus, a structure deep within the brain that is involved in memory and learning
  • The cerebral cortex, the outer layer of the brain that is involved in language and reasoning

As the disease progresses, communication between the neurons breaks down. In early stages, short-term memory begins to fail. Over time, functions such as long-term memory, language, and judgment decline. In its later stages, Alzheimer’s disease is characterized by dementia, a broad loss of cognitive (thought) function.

An estimated 4 million people currently suffer from Alzheimer’s disease. Onset of the disease usually begins after age 65. The exact cause of Alzheimer’s is unknown, although researchers are studying how nerve cells in the brain become damaged. Although Alzheimer’s is not a life-threatening illness, it cannot be cured.

What causes the damage to the nerve cells?
 Two main changes in the brain of Alzheimer’s patients cause damage to nerve cells:

  • Dense deposits of proteins called amyloid "plaques" form on nerve cells involved in memory
  • Tangled bundles of fibers (neurofibrillary tangles) form inside the body of the neurons

In the area of the brain responsible for memory, there is a loss of nerve cells and a decrease of chemicals needed for carrying messages back and forth between the nerve cells. Researchers have been studying a number of theories about why these changes occur.

What are the symptoms of Alzheimer’s?
 The symptoms of Alzheimer’s disease differ in progression and severity from person to person. Some symptoms of Alzheimer’s include:

  • Confusion and memory loss
  • Problems with accomplishing everyday tasks
  • Changes in personality
  • Wandering
  • Difficulty recognizing loved ones and friends
  • Loss of speech
  • Complete dependence on the caregiver
  • Loss of appetite

How is Alzheimer’s diagnosed?
To confirm Alzheimer’s, brain tissue must be examined. For this reason, it can be difficult to diagnose the disease. Alzheimer’s is typically diagnosed by:

  • Reviewing the patient’s medical history
  • Physical examination
  • Brain scans (PET, CT, MRI)
  • Neuropsychological testing (testing a person’s memory and cognitive skills)

What are the risk factors for Alzheimer’s disease?

  • Age (usually after 65)
  • Family history (People with relatives who have Alzheimer’s are more likely to develop the disease.)

Other possible risk factors include:

  • Head injury
  • Gender (women have a higher risk)
  • Educational level (People with lower education levels may be more likely to develop Alzheimer’s disease.)

Can Alzheimer’s be treated?
Although there is no cure for Alzheimer’s, there are medicines that can help patients with mild and moderately severe Alzheimer’s disease. These include:

Tacrine (Cognex) — Tacrine works by slowing the breakdown of acetylcholine, the chemical that helps nerve cells in the brain transmit impulses. Tacrine does not cure Alzheimer’s or slow the progression of the disease, but it can help relieve some memory impairment. Side effects of the drug include nausea, vomiting, diarrhea, abdominal pain, skin rash, and indigestion. In addition, tacrine can damage the liver so regular monitoring is necessary.

Donepezil (Aricept) — Aricept is the most widely used drug for Alzheimer’s disease. Like tacrine, Aricept inhibits the breakdown of acetylcholine. Aricept, however, has fewer and milder side effects than tacrine. Side effects include diarrhea, vomiting, nausea, fatigue, insomnia, and anorexia. Like tacrine, Aricept does not cure Alzheimer’s or slow its progression.

Rivastigmine (Exelon) or galantamine (Reminyl) — These newer drugs also work by inhibiting the breakdown of acetylcholine. In all cases, the drugs seem to help only those with mild or moderate symptoms of Alzheimer’s disease. In addition to these medicines, Vitamin E has been shown to be modestly effective in slowing progression in some patients with dementia. 

Can I protect myself from Alzheimer’s disease?
No. There is no way to prevent Alzheimer’s. However, some studies suggest that a lifetime of learning and keeping the mind active can help protect against the disease.

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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional written health information, please contact the Health Information Center at the Cleveland Clinic (216) 444-3771 or toll-free (800) 223-2273 extension 43771 or visit www.clevelandclinic.org/health/.

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