Alzheimer's Disease

Alzheimer's disease is a degenerative disorder of the brain and one of several conditions that cause dementia, a progressive decline of mental functions resulting in memory loss and confusion. About 4 million Americans have the disease and it's estimated that Alzheimer's accounts for 50 to 70 percent of all cases of dementia.

The cause of Alzheimer's is unknown but doctors are making progress in understanding and diagnosing the disease, and developing drug treatments that may slow the decline. Researchers are investigating what happens to brain cells in people with Alzheimer's disease and what genes are associated with the disorder. Most researchers believe that the cause may be a complex set of factors, including genetics, age and a person's risk for vascular diseases such as high cholesterol and blood pressure.

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The illness was first described in 1906 by a German doctor named Alois Alzheimer. Symptoms include a gradual loss of memory, problems with reasoning or judgment, disorientation, difficulty in learning, loss of language skills and a decline in the ability to perform routine tasks. Patients also may undergo changes in behavior, experiencing agitation, anxiety and hallucinations.

The incidence of Alzheimer's disease, sometimes called AD, rises with age and typically develops after age 60. Men and women are equally at risk, but more women are affected since women have a longer average life span. About 30 percent of Alzheimer's patients have a family member with the disease.

The first symptom tends to be subtle memory lapses, especially for recent events or newly learned information. These memory lapses lead to more significant gaps and confusion. Eventually, the disease leads to severe brain damage that impairs the ability to complete everyday tasks as well as to reason, learn and imagine.

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Symptoms of Alzheimer's disease include:

  • Loss of Abstract Thinking — Someone with Alzheimer's disease may lose the ability to draw conclusions and solve problems. It may become difficult to balance a checkbook, for example, because the patient has forgotten what to do with the numbers.

  • Disorientation — People with Alzheimer's disease can become lost on the street where they live, forget where they are and how they got there, and not know how to get back home.

  • Lack of Initiative — A person with the disease may become passive or unmotivated, sitting in front of the television for hours, sleeping more than usual and not pursuing his or her usual activities.

  • Language Problems — People with Alzheimer's disease often forget simple words or substitute words with inappropriate ones. An Alzheimer's patient who can't find his or her toothbrush may ask for "that thing for my mouth."
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There is no single diagnostic test that can diagnose Alzheimer's disease. The process involves several tests and may take more than a day. These tests make it possible to diagnosis Alzheimer's with an accuracy of about 90 percent.

There are two abnormal structures in the brain associated with Alzheimer's disease — amyloid plaques and neurofibrillary tangles:

  • Amyloid Plagues — Amyloid plaques are sticky clumps or patches of protein surrounded by the debris of dying nerve cells in the brain.
  • Neurofibrillary Tangles — These are the damaged remains of protein called tau, which are required for normal brain function. In Alzheimer's, threads of tau protein become twisted, which researchers believe may damage neurons and cause them to die.

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Several medications are approved to manage the disease or slow the rate of decline. Some patients improve with medication amd experience a temporary improvement soon after taking medication, but the period of improvement and stability varies. Despite treatment, it appears that Alzheimer's disease progresses in the long term.

In addition to drugs, an aerobic and weight-bearing exercise regimen may increase energy levels, reduce apathy and improve the overall sense of well-being. Since lack of motivation can be a problem, a personal trainer can be helpful to ensure participation in an exercise program.

One treatment that holds promise for the future is a vaccine that targets the beta-amyloid protein. Research on the vaccine in mice has been encouraging. Studies involving humans are in the early stages.

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Reviewed by health care specialists at UCSF Medical Center.

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