Alzheimer's Disease

Areas of the Brain Affected by Alzheimer's Disease  

Copyright © Nucleus Medical Media, Inc.

Definition  

Alzheimer's disease is a condition that destroys brain cells. People with this disease slowly lose the ability to learn, function, and remember. It is the most common cause of dementia. Dementia is a loss in mental abilities that is great enough to interfere with daily life.

Causes  

The cause of Alzheimer's is not yet known. Two factors that may play a role in the development of Alzheimer's disease are:

• Plaques—Abnormal deposits of a substance called beta amyloid in different areas of the brain
• Neurofibrillary tangles—Twisted fibers (called tau fibers) within the nerve cells

Risk Factors  

Factors that may increase your chance of Alzheimer's disease include:

• Age: 65 and older
• Previous serious, traumatic brain injury
• Lower educational achievement
• Down's syndrome
• Down's syndrome in a first-degree relative
• Women under age 35 who give birth to a child with Down's syndrome
• Smoking
• Family history of Alzheimer's disease
• Presence of a certain type of protein (APOE-e4)
• Depression
• Elevated levels of homocysteine
• Heart disease

Researchers are studying the following to see if they are related to Alzheimer's disease:

• Poor nutrition and vitamin deficiency in childhood
• Excess metal in the blood, especially zinc, copper, aluminum, and iron
• Certain viral infections
• Diabetes
• High cholesterol

Symptoms  

The disease begins as mild memory lapses. It will continue toward a profound loss of memory and function. Alzheimer's disease is divided into three stages:

• Early—Loss of memory, reasoning, understanding, or learning, but does not interfere with independence
• Intermediate—Increased mental loss, personality changes, and increased dependence on others for basic needs
• Severe—Loss of personality and bodily functions with total dependence on others for care

Symptoms include:

• Increasing trouble remembering things, such as:
  • How to get to familiar locations
  • What the names of family and friends are
  • Where common objects are usually kept
  • How to do simple math
  • How to do usual tasks, such as cooking, dressing, bathing, etc.
• Having difficulty concentrating on tasks
• Having difficulty completing sentences due to lost or forgotten words (may progress to complete inability to speak)
• Forgetting the date, time of day, or season
• Getting lost in familiar surroundings
• Having mood swings
• Being withdrawn, losing interest in usual activities
• Having personality changes
• Walking in a slow, shuffling way
• Having poor coordination
• Losing purposeful movement

Diagnosis  

There are no tests to confirm Alzheimer's. The doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor will ask many questions. This will help to rule out other causes.

Tests to rule out other medical conditions may include:

• Neurological exams—Tests of your nervous system
• Psychological and mental status testing
• CT scan—A type of x-ray that uses a computer to make pictures of your brain
• MRI scan—A test that uses magnetic waves to make pictures of your brain
• Electroencephalogram (EEG)—A test that measures electrical currents in your brain
• Blood tests and urine tests
• Lumbar puncture—To test for levels of certain brain proteins that increase with Alzheimer’s disease and to rule out other disorders
• Positron emission tomography (PET) scan of the brain—A test that makes images showing activity in your brain

Treatment  

There is no cure for Alzheimer's disease. There are no certain ways to slow its progression. Four medicines are available to treat some of the symptoms. Other drugs are being studied. The goal is to find a medicine that can manage the symptoms or slow the condition's course.