When it comes to Alzheimer's disease, a big barrier to progress has been the myth of the aged, the myth of inevitable senility. Myths flourish when information is scarce, and only recently have people begun to understand what happens to the aging brain.
We've only recently counted the number of human chromosomes and begun to unlock the mysteries of DNA, Dr. Roger Brumback says.
The idea of inevitable old-age senility, says the professor of pathology and psychiatry at Creighton University, was fostered by the German welfare system that arose in 1870s. It institutionalized the notion that people's minds fall apart at age 65, so you needed to remove the old from government and let in the young.
This decline among those older than 65 was called senile dementia. It appeared to be accompanied by senile plaques and fibrous tangles forming in the brain.
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These plaques consist of thick, sticky deposits of beta-amyloid mixed with other proteins, all remnants of neurons and other cells. At the microscopic level, many of the brain's 100 billion nerve cells appear to be suffocated by the plaques.
At the turn of the last century, Dr. Alois Alzheimer encountered a woman in her 50s who over a four-year period showed signs of progressive dementia. Upon her death, he performed an autopsy, discovering she had the same senile brain plaques and fibrous tangles found in people older than 65.
Alzheimer first lectured on his discovery in 1906. Because everybody older than 65 was assumed to have these plaques, the disease described those who got it early. It was a time of great medical rivalry, and Alzheimer's boss succeeded in getting the premature appearance of plaques and tangles named for his student.
Alzheimer's notion of the disease persisted for decades.
Even in the 1950s, Brumback says, Alzheimer's was believed to be rare, because by definition it had to occur before age 65.
It is true that the longer one lives, the greater the odds of getting the disease. A small percentage of people younger than 73 have Alzheimer's, but about half of everyone older than 85 has it.
It's also true that mental abilities naturally decline slightly with advancing age, but Alzheimer's ravages the brain. The damage is plainly visible at autopsy.
In 1900, at the time of Alzheimer's discovery, the average life expectancy was 47 years. It was rare to live to 85. Today, people can expect to live to age 77.
By the 1960s, some researchers began to question Alzheimer's assumptions. Did it make sense that on the day before your 65th birthday you had Alzheimer's, but on the day after you had senile dementia?
Some people, like Irving Berlin, continued to perform brilliantly well into their 90s. Among the elderly, there appeared to be a continuum of abilities.
In the late 1970s, researchers pieced the neurology and pathology together, and in the 1980s, scientists convened a National Institutes of Health forum to reach agreement on a definition of the disease. The 1980s also saw the rise of Alzheimer's day centers, which pioneered new ways of dealing with patient behaviors.
And yet, Brumback says, there remains this belief in old-age senility.
"I see this as I talk to families," he says. When he suggests testing an older person to see if they have a curable form of dementia, he hears: I don't want to spend $10,000 if they're going to be senile anyway.
