According to the National Institutes of Health, 2.4 to 4.5 million Americans have Alzheimer's disease, the most common form of dementia in the elderly.
While we know Alzheimer's disease gradually destroys a person's ability to think, reason or recall memories, there is no way to diagnose it without performing an autopsy, clearly too late to help doctors trying to help the person live with the ailment.
Diagnosis consists of looking at signs of cognitive decline, among other measures. But making a definite diagnosis is, at present, not possible.
Treatment, too, has been elusive. While the disease has been linked to the accumulation and hardening of proteins known as beta amyloid on the surface of the brain, researchers were able to develop a trial vaccine that eliminated the beta amyloid plaques but did not prevent the development of Alzheimer's. And researchers have found people who have the plaques but do not display any signs of dementia.
It has become clear that Alzheimer's will take significantly different courses in different people, and, like cancer, likely has a multitude of causes.
Because Alzheimer's disease's origins and course remain a mystery, perhaps it should come as no surprise that different doctors have different approaches to the disease.
Dr. Peter Whitehouse, founder of the University Memory and Aging Center at University Hospitals and Case Western Reserve University, and author of "The Myth of Alzheimer's," approaches Alzheimer's as one of many natural courses of aging, rather than as a disease that requires immediate diagnosis.
That involves encouraging lifestyle changes and social activity in senior citizens, rather than focusing on medications to treat Alzheimer's.
Other physicians don't agree with Whitehouse's entire thesis, but they don't necessarily think it's an obstacle to treating Alzheimer's and helping patients with its symptoms.
"Whether it's part of normal aging or not, I think it is immaterial to whether we, as a society, say that it's something we don't like, and we call it a disease and develop treatments for it," said Dr. Jason Karlawish, an associate professor of medicine at the University of Pennsylvania and director of the school's Alzheimer's Disease Center's Education and Information Transfer Core.
"I don't have a problem with saying something is normal aging, but ... I think we have every reason to still provide treatment for it," he said.
That treatment, however, can prove costly, and Karlawish notes that economic concerns will play a major role in how Alzheimer's disease is treated in the years to come.
"Ultimately, it's an economic problem," he said. "I think we need to carefully, rationally develop therapeutics for it."
In an era where health reform is a hot topic, and as the nation analyzes how to spend its resources, how to pay for Alzheimer's disease care likely will play a central role.
It's important to mention that "with the aging of the population ... what this means is that there's going to be a tsunami," said Dr. James Grisolia, chief of neurology at Scripps-Mercy Hospital in San Diego. "Finding ways to treat and prevent [Alzheimer's] is going to be huge."