People with Alzheimer's disease and those with mild cognitive impairment, or even healthy people who want to help scientists test new treatments may be able to take part in clinical trials. Clinical trials are studies done with people to find out if a new drug or treatment is both safe and effective.
New therapies are tested on people only after laboratory and animal studies show that the therapy is safe and has promising results. The Food and Drug Administration sets strict rules to make sure that people who agree to be in the studies are treated as safely as possible.
People who take part in clinical trials say that the biggest benefit is having regular contact with experts who have lots of practical experience and a broad understanding about the disease. They also feel they are making a valuable contribution to knowledge that will help people who develop Alzheimer's in the future.
Scientists are testing a number of drugs in clinical trials to see if they prevent Alzheimer's disease, slow the disease, or help reduce behavioral symptoms. Many drugs and therapies are tested in clinical trials. Some ideas that seem promising turn out to have little or no benefit when they are carefully studied in a clinical trial.
There is evidence that inflammation in the brain may contribute to the damage caused by Alzheimer's disease. Some studies have suggested that drugs such as nonsteroidal anti-inflammatory drugs, or NSAIDs, might help slow the progression of Alzheimer's. So far, however, clinical trials have not shown a benefit from these drugs.
Research has suggested a link between Alzheimer's disease and factors that increase the risk for heart disease. Medicines already used to help reduce the risk of heart disease may help lower the chances of developing Alzheimer's disease or may slow its progression. Clinical trials of drugs known as statins, commonly used to lower cholesterol, have begun to see if they might help slow down the progression of Alzheimer's disease.
Studies have shown that people with Alzheimer's often have higher levels of an amino acid called homocysteine in their blood. High levels of homocysteine are known to increase the risk of heart disease. Folic acid and vitamins B6 and B12 can reduce levels of homocysteine in the blood, and scientists are conducting clinical trials to see whether these substances can also slow rates of mental decline.
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.
Several years ago, a clinical trial showed that vitamin E slowed the progress of some consequences of Alzheimer's disease by about seven months. Other studies are considering whether antioxidants -- such as vitamin E and C -- can slow Alzheimer's. One clinical trial is examining whether vitamin E and/or selenium supplements can prevent Alzheimer's or stop mental decline. More studies on other antioxidants are ongoing or being planned.
Studies have linked keeping the brain active with a reduced risk of Alzheimer's disease. In a study of healthy older people and people with possible or probable Alzheimer's, scientists found that the healthy people had taken part in more mentally stimulating activities in their early and middle adulthood years than those who later developed Alzheimer's. The healthy group also spent more hours in these types of activities.
A growing body of research suggests that the more formal education a person has, the better his or her memory and learning ability will be, even if the brain turns out to have the type of plaques associated with Alzheimer's disease.
Some studies have suggested that estrogen used by women to treat the symptoms of menopause also protects the brain. Experts also wondered whether using estrogen could reduce the risk of Alzheimer's or slow the disease. However, clinical trials to test estrogen have not shown that it can slow the progression of Alzheimer's in women who have already been diagnosed with the disease. And one study found that women over the age of 65 who used estrogen with a progestin were at greater risk for dementia, including Alzheimer's. The study also showed that older women who used only estrogen could increase their risk of developing dementia. Scientists believe that more research is needed to find out if estrogen may play some role in Alzheimer's. They would like to know whether starting estrogen therapy around the time of menopause, rather than at age 65 or older, will protect memory or prevent Alzheimer's disease, and an NIH clinical trial is testing this possibility.
Early studies suggested that extracts from the leaves of the ginkgo biloba tree might be of some help in treating symptoms of Alzheimer's disease. There is no evidence yet that gingko biloba will cure or prevent Alzheimer's. Scientists are now trying to find out in a clinical trial whether ginkgo biloba can delay mental decline or prevent Alzheimer's disease or other types of dementia in older people.
Will a vaccine someday prevent Alzheimer's disease? Early vaccine studies in mice successfully reduced beta-amyloid plaques in the brain and improved the way mice performed on memory tests. But when the studies were conducted in humans, they had to be stopped because some participants experienced side effects. However, scientists are continuing to study variations of the vaccine approach in the hope that they will reduce beta-amyloid in the brain while minimizing harmful side effects.
Scientists have come a long way in their understanding of Alzheimer's disease. Findings from years of research have begun to clarify differences among age-related memory changes, mild cognitive impairment, and Alzheimer's disease. Scientists also have made great progress in defining the changes that take place in the Alzheimer's disease brain. This allows them to pinpoint possible targets for treatment.