June 15, 2009
Dr. Srinivas Nimmagadda
Dementia is a brain disorder that seriously affects a person's memory, thinking and reasoning skills. People with dementia often have trouble thinking and speaking clearly, remembering recent events and learning new things. Over time, it becomes hard for them to handle daily activities and take care of themselves. There are many causes of dementia, but Alzheimer's disease is the most common cause of dementia in older persons.
Scientists think up to 4.5 million people in the United States suffer from Alzheimer's disease. The disease usually begins after age 65 and risk goes up with age. While younger people also may get Alzheimer's disease, it is much less common.
About 5 percent of men and women ages 65 to 74 have Alzheimer's disease, and nearly half of those age 85 and older may have the disease. It is important to note, however, that Alzheimer's disease is not a normal part of aging.
Alzheimer's disease is named after Dr. Alois Alzheimer, a German doctor. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. He found abnormal clumps and tangled bundles of fibers. The clumps are now called amyloid plaques and the tangles are called neurofibrillary tangles. Today, these plaques and tangles in the brain are considered signs of Alzheimer's disease.
Scientists also have found other brain changes in people with Alzheimer's disease. There is a loss of nerve cells and pathways in areas of the brain that are vital to memory and other mental abilities. There also are lower levels of some of the chemicals in the brain that carry complex messages back and forth between nerve cells.
Alzheimer's disease may disrupt normal thinking and memory by blocking these messages between nerve cells.
Causes and Risk Factors
Scientists do not yet fully understand what causes Alzheimer's disease. There probably is not one single cause, but several factors that affect each person differently. Age is the most important known risk factor for Alzheimer's disease. The number of people with the disease doubles every five years beyond age 65.
Family history is another risk factor. Scientists believe that genetics may play a role in the causes of Alzheimer's disease. For example, early-onset familial Alzheimer's disease, a rare form of Alzheimer's disease that occurs between the ages of 30 and 60, is inherited.
The more common form of Alzheimer's disease is known as late-onset. It occurs later in life, and no obvious family pattern is seen in most cases. One risk factor for this type of Alzheimer's disease is a gene that makes one form of a protein called apolipoprotein E, or apoE.
Everyone has apoE, which helps carry cholesterol in the blood. Only about 15 percent of people have the form that increases the risk of Alzheimer's. It is likely that other genes may also increase the risk of Alzheimer's or protect against it, but they remain to be discovered.
Scientists still need to learn a lot more about causes and risk factors. In addition to genetics and apoE, they are studying education, diet, environment, and molecular changes in the brain to learn what role they might play in the development of this disease.
Scientists are finding more clues that some of the risk factors for heart disease and stroke-like high blood pressure, high cholesterol, and low levels of the vitamin folate-may also increase the risk of Alzheimer's. Researchers are also investigating the possibility that physical, mental and social activities may protect against Alzheimer's.
Studies have shown that keeping the brain active may be associated with a reduced risk of Alzheimer's. There are no treatments, drugs, or pills that can prevent Alzheimer's, but people can take some steps that may reduce their risk. These include:
A healthy diet is important. Although no special diets or nutritional supplements have been found to prevent or reverse Alzheimer's disease, a balanced diet helps maintain overall good health.
Research has not shown that these steps will lower your risk for Alzheimer's, and studies designed to directly test their ability to do so are currently in progress. However, all of these things are good to do anyway because they lower the risk for other diseases and help maintain and improve your overall health and well-being.
Symptoms and Diagnosis
Alzheimer's disease begins slowly. At first, the only symptom may be mild forgetfulness. People in the early stage of Alzheimer's disease may have trouble remembering recent events, activities, or the names of familiar people or things. Simple math problems may become hard to solve. Such difficulties may be a bother, but usually they are not serious enough to cause alarm.
However, as the disease goes on, forgetfulness begins to interfere with daily activities. People may forget the way home or find it hard to cope with daily life. Such symptoms are more easily noticed and become serious enough to cause people with Alzheimer's disease or their family members to seek medical help.
People in the middle stages of Alzheimer's disease may forget how to do basic tasks, like brushing their teeth or combing their hair. They can no longer think clearly. They begin to have problems speaking, understanding, reading or writing. Later on, people with Alzheimer's disease may become anxious, agitated or aggressive, or wander away from home. Eventually, patients need total care.
An early, accurate diagnosis of Alzheimer's disease helps patients and their families plan for the future. It gives them time to discuss care options while the patient can still take part in making decisions. And even though no drug can slow the onset or the progression of Alzheimer's, early diagnosis offers the best chance to treat the symptoms of the disease.
Today, the only definite way to diagnose Alzheimer's disease is to find out whether there are plaques and tangles in brain tissue. To look at brain tissue, doctors must wait until they do an autopsy.
Therefore, doctors can only make a diagnosis of "possible" or "probable" Alzheimer's disease while the person is still alive. At specialized centers, doctors can diagnose Alzheimer's disease correctly up to 90 percent of the time.
Doctors use several tools to diagnose "probable" Alzheimer's disease:
Sometimes, these test results help the doctor find other possible causes of the person's symptoms. For example, thyroid problems, drug reactions, depression, brain tumors, and blood vessel disease in the brain can cause symptoms similar to those of Alzheimer's. Some of these other conditions can be treated successfully.
Recently, scientists have focused on a type of memory change called mild cognitive impairment, or MCI. MCI is different from both Alzheimer's disease and age-related memory change. People with MCI have ongoing memory problems but do not have noticeable problems in other areas like confusion, attention problems, and difficulty with language.
Treatments and Research - Treatments
Alzheimer's disease develops slowly, starting with mild memory problems and ending in death. The course the disease takes and how fast changes occur vary from person to person. The time from diagnosis to end of life varies. It can be as little as three years if the person is over 80 when diagnosed. Or it may be as long as 10 years or more if the person is younger.
A person with Alzheimer's should be under a doctor's care and may see a neurologist, psychiatrist, family doctor, internist, or geriatrician-a specialist who treats older adults. The doctor can treat the person's physical and behavioral problems and answer the many questions that the person or the family may have.
No treatment can stop Alzheimer's disease. However, for some people in the early and middle stages of the disease, the medication may help prevent some symptoms from becoming worse for a limited time.
Also, some medicines may help control behavioral symptoms of Alzheimer's disease such as sleeplessness, agitation, wandering, anxiety and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.
Family members and friends can assist people in the early stages of Alzheimer's in continuing their daily routines, physical activities and social contacts. People with Alzheimer's should be kept up-to-date about the details of their lives, such as the time of day, where they live, and what is happening at home or in the world.
Memory aids may help in the day-to-day living of patients in the earlier stages of Alzheimer's. Some families find that a big calendar, a list of daily plans, notes about simple safety measures, and written directions describing how to use common household items are very useful aids.