What is Alzheimer's Disease?

Alzheimer's disease (AD) is a progressive, degenerative brain disease that results in impaired memory, thinking, and behavior. It is the most common cause of dementia in the elderly and affects at least three to four million people in the United States. People with AD experience gradual memory loss as well as impaired judgment, difficulty concentrating, loss of language skills, personality changes, and a decline in the ability to learn new tasks. Memory loss usually begins at about age 65 and symptoms tend to become severe within 8 to 10 years. In some cases, symptoms may appear earlier in life and advance at a faster or slower rate, but most people who develop symptoms before the age of 60 tend to have more severe forms of the disease. Currently, there is no cure for AD, but studies suggest that medications, herbs and supplements, and lifestyle adjustments may all help to slow the progression and improve the symptoms of the disease.

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Alzheimer's Signs and Symptoms

The early symptoms of AD are occasionally overlooked because they resemble signs that many people attribute to "natural aging." The following are the most common signs and symptoms of AD.

Alzheimer's Psychological Symptoms

• Memory loss, including not recognizing friends and family members
• Difficulty concentrating
• Difficulty comprehending words, completing sentences, or finding the right words
• Loss of familiarity with surroundings, wandering aimlessly
• Depression
• Hallucinations, delusions, and psychosis
• Aggression, agitation, anxiety, restlessness
• Accusatory behaviors (such as accusations of spousal infidelity)
• Withdrawal, disinterest, hostility, loss of inhibitions

Alzheimer's Physical Symptoms

• Impaired movement or coordination
• Muscle rigidity, shuffling or dragging feet while walking
• Insomnia or disturbances in sleep patterns
• Weight loss
• Incontinence
• Muscle twitching or seizures

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Alzheimer's Causes

The causes of AD are not entirely known but are thought to include genetics and environmental factors. New research indicates that free radicals (highly reactive molecules that can cause oxidation, or damage to cells) may play a role in the development of AD.

Scientists also believe the environment may play a part in AD because people in different regions of the world have widely varying risks of developing the disease. For example, people living in Japan and West Africa have much less risk for AD than Japanese and Africans living in the United States.

People with AD have abnormal deposits, or plaques, in their brain tissue. These plaques contain beta amyloid, a protein that releases free radicals, or highly reactive molecules that can cause damage to cells through a process called oxidation. These free radicals are believed to lower levels of acetylcholine (a brain chemical that helps transmit impulses in the nervous system) and damage brain tissue, bringing on the symptoms of AD.

Although not confirmed by scientific studies, other factors that have been speculated to contribute to the development of AD include infections (such as herpesvirus type 1), exposure to metal ions (such as aluminum, mercury, zinc, copper, and iron), or prolonged exposure to electromagnetic fields.

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Reviewed: 03/2006