There are few diseases as frightening as Alzheimer’s. Most diseases, even if they ravage your body, leave your mind intact. Alzheimer’s leaves the body intact but robs victims of their memories and personality. No wonder it is sometimes called “dying by inches.”
There is neither a cure nor an effective treatment –but there is hope. Breakthroughs are coming fast and furious, and within a few years, there may be treatments that allow us to, if not cure the disease, at least slow or even halt its progression.
Alzheimer’s Disease was identified in 1906 by Dr. Alois Alzheimer, a German neuropathologist, in the brain of a 55-year-old patient who had spent the last year of her life in a mental institution. For many years, the disease was considered an oddity that only affected a small group of patients under the age of 60; older patients who exhibited the same symptoms were thought to be suffering from “senile dementia,” which itself was very rare: in 1906, life expectancy was less than 50 years. As life expectancy increased, however, “senile dementia” became increasingly common, and in the 1960s researchers finally realized “senile dementia” and Alzheimer’s were often the same.
Alzheimer’s is primarily a disease of old age. One in 20 Canadians over 65 have it–more than 200,000 people. The incidence increases with age. One in 100 Canadians between 65 and 74 have Alzheimer’s, one in 14 between ages 75 and 84, and one in four over 85.
Alzheimer’s is difficult to diagnose because more than sixty different problems, from strokes to medication, can product dementia. To diagnose Alzheimer’s, the doctor has to rule out as many of the other possible causes as he can. Even then, he can only say that a particular patient likely has Alzheimer’s; the only way to be certain is to examine brain tissue under a microscope after death.
Such an examination will reveal two major abnormalities, called “amyloid plaques” and “neurofibrillary tangles.”
Amyloid plaques are sticky deposits formed from a naturally occurring protein called beta amyloid protein. Neurofibrillary tangles are made up of tau proteins, which ordinarily reinforce important structures in brain cells called microtubules, holding them together like the crosspieces in a stretch of railroad track. In people with Alzheimer’s, these tau proteins have broken loose to form tangles. Without tau proteins reinforcing them, the microtubules disintegrate and the whole brain cell withers and dies.
Although scientists know that these changes occur in the brains of people with Alzheimer’s, they’re still not sure what causes the disease. Some believe the build-up of plaques is the primary cause. Some believe the formation of tangles is. And some believe there is another cause entirely, and plaques and tangles are just symptoms.
Partly because the cause of Alzheimer’s still isn’t known, there is no effective treatment for it. Only three drugs exist to treat Alzheimer’s; all ease the symptoms of the disease by inhibiting the breakdown of a brain chemical called acetylcholine, which is vital for nerve cells to communicate with each other. Some patients don’t respond at all; even when they do the drugs only work for six to nine months, at best.
But a number of new approaches are being explored now, many of which were discussed at the World Alzheimer’s Congress held in Washington, D.C., last month. Researchers at Elan Pharmaceuticals have developed a vaccine that not stopped mice from developing amyloid plaques and destroyed the plaques in mice that had already developed them. That vaccine is already entering human safety trials, but it will still be some time before we know if it works.
New drugs to boost brain function are being tested. As well, research is pointing up risk factors, such as high cholesterol and head injuries. There are also some indications that anti-oxidants such as Vitamin E and anti-inflammatory drugs such as ibuprofen may reduce the risk. Research also indicates that people who are better-educated and keep their brains active during their lives are less likely to develop Alzheimer’s than less mentally active people.
As life expectancies increase and the world population grows, the number of people with Alzheimer’s will mushroom. More than 22 million people could have the disease worldwide by 2025, and the total could be 45 million worldwide by 2050–as many people as suffer from all types of cancer.
For the first time, though, there is hope that Alzheimer’s disease may one day become a serious but treatable condition–no longer the terrifying mind-thief that it is now.
