What Alzheimer's Disease Is and Is Not

Alzheimer's disease (AD) is a form of dementia. Although all AD patients have dementia, not all dementia patients have AD. The Alzheimer's Association defines Alzheimer's disease as "an irreversible, progressive brain disease that slowly destroys memory and thinking skills, eventually even the ability to carry out the simplest tasks." AD is a fatal disease, ending inevitably in death.

Alzheimer's disease was named after a German physician, Alois Alzheimer, who first identified the condition in 1906 when he performed an autopsy on the brain of a woman who'd been suffering severe memory loss and confusion for years.

He observed microscopic amyloid plaques and neurofibrillary tangles in the woman's brain tissue under a microscope. He then correctly hypothesized that these abnormal deposits were responsible for the patient's loss of memory and other cognitive problems.

To this day, AD can only be diagnosed with 100 percent accuracy through an autopsy that reveals the presence of the characteristic plaques and tangles in the brain. However, a comprehensive examination and good work-up do provide a reliable diagnosis with greater than 90 percent accuracy.

Abnormal deposits of specific proteins inside the brain disrupt normal brain function and cause the cognitive and functional problems typically associated with AD. Eventually, as these deposits spread throughout the brain, brain tissue starts dying, which leads to further cognitive impairment. The resulting brain shrinkage can be seen in CT scans and MRI scans.

Current research is focused on trying to determine what causes these deposits and is looking for ways to prevent or reverse them before they cause permanent brain damage.

AD is not

• Curable
• Contagious
• A natural part of the aging process
• Something you get from using deodorant or cooking in aluminum pans
• Inevitable if you live long enough

Although certain familial forms of AD do run in families, these forms are extremely rare, accounting for less than 5 percent of all cases. So just because your mother or your brother got AD doesn't automatically mean that you're going to get it as well.

No test can predict whether you'll get AD unless you have the very rare inherited form of AD. A blood test exists that can tell you whether you have a certain form of a cholesterol-carrying protein associated with a higher incidence of AD, but that's all that it can tell you. The test can't tell you whether you'll actually develop the condition because at least 50 percent of the people who have the risk factor never get AD.

For ethical reasons, healthcare professionals advise against taking this blood test or undergoing other genetic testing because they want to spare their patients unnecessary worry about something that'll probably never happen even if the tests do come out positive. They also recommend against testing because if a person does find that he has inherited the gene or the risk factor, this information may negatively impact the person's ability to get long-term care coverage and lead to increased cost for health insurance.