Alzheimer's disease is a brain disorder which gradually destroys the ability to reason, remember, imagine, and learn. It's different from the mild forgetfulness normally observed in older people. Over the course of the disease, people with Alzheimer's no longer recognize themselves or much about the world around them. Depression, anxiety, and paranoia often accompany these symptoms. Although there is no cure, new treatments help lessen Alzheimer's symptoms and slow its progression.

Alzheimer's is marked by abnormal clumps (called senile plaques) and irregular knots (called neurofibrillary tangles) of brain cells. For reasons not well understood, these plaques and tangles take over healthy brain tissue, devastating the areas of the brain associated with intellectual function.

Over four million people in the United States are living with Alzheimer's disease, which is the most common form of dementia. Experts predict that as baby boomers age, Alzheimer's may affect as many as 14 million people nationwide. Alzheimer's is widespread, affecting 10% or more of those over age 65 and nearly half of those over age 85. Slightly more women than men have Alzheimer's disease. Its increasing prevalence has led epidemiologists to call Alzheimer's "the disease of the century. "

While Alzheimer's disease usually affects those over age 65, a rare and aggressive form of Alzheimer's can happen in some people in their 40s and 50s. Alzheimer's disease progresses slowly, taking between three to 18 years to advance from the earliest symptoms to death; the average duration of the disease is eight years. Death results not from the disease itself but from some secondary illness such as pneumonia or urinary tract infection. Right now, treatment of Alzheimer's disease focuses on slowing its progression and coping with its symptoms.

In the early and middle stages of Alzheimer's disease, people with the illness may be painfully aware of their intellectual failings and what is yet to come. At this stage and throughout the course of the illness, it's vitally important to support their mental and emotional well-being with the help of their doctor, social worker, or psychological counselor. Show them love, affection and warmth as they make their journey.

Risk factors and prevention
The following factors increase risk of Alzheimer's disease:
Increasing age
Family history
Genetics
Down syndrome
There is no sure-fire way to prevent the onset of Alzheimer's disease. But some preventive treatments (such as estrogen for women) are promising.

Symptoms and diagnosis

At its onset, Alzheimer's disease is marked by simple forgetfulness, especially of recent events or directions to familiar places. People with Alzheimer's may have personality changes, such as poor impulse control and judgment, distrust, increased stubbornness, and restlessness.

The next stage of the disease is characterized by greater difficulty in doing things that require planning, decision-making, and judgment -- for example, working, balancing a checkbook, or driving a car. Everyday skills such as personal grooming aren't affected, but social withdrawal begins.

Eventually, people with Alzheimer's disease can't do simple tasks of daily living such as eating, bathing, and using the toilet. They may lack interest in personal hygiene and appearance, and lose their usual sexual inhibitions. They may have a hard time recognizing all but their closest daily companions. Communication of all kinds becomes difficult as written and spoken language ability dwindles. Withdrawal from family members begins and the person may become agitated, displaying belligerence and a denial of the illness.

In the last stages of the disease, people with Alzheimer's become bedridden, unable to recognize themselves or their closest family members. They may make small, purposeless movements and communicate only by screaming out occasionally. Essentially, the brain forgets how to live. Death often results from pneumonia and from complications of immobility.

Currently, doctors can't diagnose Alzheimer's disease with 100% certainty until a brain autopsy after the person's death reveals the disease's markers: abnormal clumps and irregular knots of brain cells. So diagnosis of Alzheimer's rests largely on the judgment of physicians experienced in dealing with dementing illnesses. But that judgment has become quite sophisticated. Experts estimate current diagnostic accuracy at around 90%.

Treatment

Since there are so few treatments for Alzheimer's disease, many of the available therapies attempt to improve the quality of patients' lives, keep them safe, and make caring for them easier. The primary care doctor will closely watch the progress of the person with Alzheimer's to check for medical complications, adjust medications to reach the lowest effective dosage, and assess any changes in drugs used. The doctor may do mental status tests routinely to chart the course of the illness. Support for the main caregiver is also important, and the doctor will help determine at what point the person with Alzheimer's may need professional nursing care outside the home.

Experts are upbeat that new treatments will, in the not-too-distant future, turn the illness into a manageable chronic condition, similar to diabetes or asthma. But progress comes slowly, and to date, there have been no breakthroughs.

Terminology

Today, the condition is known as Alzheimer's disease (AD), or dementia of the Alzheimer's type (DAT). Some experts are starting to drop the apostrophe "s," calling the condition Alzheimer disease (paralleling the name change from Down's syndrome to Down syndrome), but most authorities continue to use the apostrophe "s" -- Alzheimer's disease.

Alzheimer's disease is sometimes called "pre-senile dementia," and sometimes "senile dementia." In medical jargon, the term "senile" simply means "old." In common usage, however, it denotes a loss of mental faculties. As a result, some people get confused by pre-senile dementia. In common usage, it seems like a contradiction in terms -- dementia before you've lost mental acuity. Actually, in medical jargon, "pre-senile" simply means "younger than 65". Doctors use pre-senile dementia to describe Alzheimer's disease that develops before age 65, and senile dementia for Alzheimer's that develops after 65. Either way -- pre-senile or senile -- it's the same disease.

The term "dementia" may cause problems as well. In common usage, "demented" often implies wildly out of control. In medical jargon, it simply describes a loss of cognitive function. Many people with Alzheimer's develop behavior problems, but some do not.

Cost and research-funding statistics

Experts estimate that Alzheimer's disease costs the United States $80 billion to $100 billion a year in lost productivity, medical care, and personal caretaking.

For people with Alzheimer's cared for at home, the average out-of-pocket cost to family caregivers (excluding lost wages) is $12,500 per year.

For people with Alzheimer's in nursing homes, the average cost is $42,000 per year per person.

The average cost of caring for a person with Alzheimer's from diagnosis until death is $174,000, making Alzheimer's disease the nation's third most costly illness, after heart disease and cancer.

The Alzheimer's disease federal research budget has grown substantially over the past decade, to more than $400 million in 1999. But that figure represents only a small fraction of what the disease costs.