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."
Grisolia added that currently the cost for the care and treatment of people with Alzheimer's is on the order of $80 billion, and if you look at the caregiver costs, "it's going to get bigger."
Appropriately for a complex disease, much of what you might hear about Alzheimer's isn't completely true -- or completely false. So we spoke to a number of top experts in Alzheimer's research to explore some nuances of the myths surrounding this condition.
Fact or Myth? Alzheimer's only afflicts the elderly.
Alzheimer's disease is certainly more common in elderly people, but it can occur sooner in life.
"There are people in their 40s, 50s and 60s who have what we call early onset," said Whitehouse.
In those earlier cases, he said, family history is a strong predictor.
"When it's under 65, you are more likely to have a strong genetic history," said Whitehouse.
Karlawish agreed, noting that while Alzheimer's most commonly affects people over the age of 65, people significantly younger can get the disease.
He said that the youngest person he has treated was 52 at the onset, but patients like that "[are] not, by any means, the most common group. That's very uncommon."
And so, Whitehouse said, while Alzheimer's may affect some middle-aged patients, it is typically a problem that plagues older people.
"The young-age-of-onset cases do not, in my opinion, take away from the general claim that Alzheimer's is, more commonly, a part of aging," he said.
Fact or Myth? Memory loss is an inevitable part of aging.
"Memory loss, as a symptom, happens pretty much to everybody as they age," said Dr. Constantine Lyketsos, director of the Neuropsychiatry Service at Johns Hopkins Medical Institution.
He noted that younger people will almost always perform better on memory tests in a lab than their older counterparts.
"Your memory is definitely less good when you're older," said Lyketsos.
But he noted that while memory loss may occur, that does not mean Alzheimer's will follow.
"There clearly are people who can live to a ripe old age -- 90s, 100s -- without dementia," said Lyketsos.
Dr. Gary Small, director of the UCLA Center on Aging, reiterated that sentiment.
"The brain tends to age like other organs, but it's generally not incapacitated and usually mild," he said.
However, he noted, "the average person notices a delay in retrieval of information."
Fact or Myth? Exercise can help you preserve your memory longer.
Answer: Probably a fact
This one is likely true.
A number of large studies have shown that regular exercise seems to show benefits in preventing cognitive decline in the elderly adults who are at risk.
"I'm pretty adamant about people getting good cardiovascular conditioning to protect their brain," said Small.
But while it seems clear that exercise shows some benefits in limiting people's cognitive decline, physicians remain unsure of how, exactly, that happens.
"It's probably increased circulation," said Small, noting that the circulation brings nutrients such as oxygen and glucose to the brain.
"You need all kinds of good circulation to bring in the nutrients and take away the excretions," Small said.
Whitehouse noted that even among researchers who study diseases in mice, the benefits of exercise to combat Alzheimer's or any other illness seem clear.
The most effective intervention across the board, he said, is to put an exercise wheel in the cage.
He said that increasing exercise is a recommendation he makes to all of his patients.
One other factor, noted Grisolia, might be that some cases of Alzheimer's could be due to small strokes in the brain, a condition that wouldn't necessarily be clear to a researcher.
"One of the things that's tough about that, if you don't have a chance to examine the brains ... it's hard to tell how much Alzheimer's disease versus how much stroke damage there is in a person," he said.
In that case, patients may be benefiting by avoiding those strokes.
"Maybe that's why people with exercise are less likely to develop Alzheimer's disease," he said. "We haven't really settled the question of why exercise works."
Fact or Myth? People with higher education levels have a faster memory decline.
Answer: Not really
Higher education levels -- either through schooling of self-education -- may actually help stave off declines due to Alzheimer's for longer.
"There are lots of studies that show more learning and more stimulation seems to actually protect against Alzheimer's," said Grisolia.
Patients who have higher education levels also tend to have better cognitive reserves, which helps their brain adjust to changes Alzheimer's may bring.
Karlawish said that patients with higher education levels may also have more flexible brains that can adjust to the circumstances.
However, it appears that, in some cases, these patients might decline faster once a decline begins.
"Once they get Alzheimer's, the data suggests that they tend to progress faster," said Karlawish.
At the same time, the changes might simply be more noticeable because they are more obvious in patients who often had more cognitive abilities to begin with.
"What seems to happen is that it's more noticeable because they have family members and other people who are all over it as soon as they start to get challenges," said Grisolia.
Whitehouse noted that another problem might be the work done by people with higher levels of education.
"People who have more intellectual jobs and more education tend to have more IQ in the first place," he said.
Therefore, they may be quicker to notice any changes they may experience.
Fact or Myth? Brain games can delay or prevent Alzheimer's disease.
While many brain games are marketed to the elderly with the promise of preventing or delaying Alzheimer's disease, it's unclear that they actually deliver on their promises.
"That's not proven for sure," said Small.
Doctors often recommend that people at risk engage in activities like crossword puzzles or other mental exercises, but the benefits aren't yet clear.
"People who exercise their minds by doing crossword puzzles, et cetera, are less likely to develop Alzheimer's down the line," said Lyketsos.
The problem, he said, is that a randomized clinical trial, where similar patients either did or did not do these puzzles and were followed to see who developed Alzheimer's, would be needed to ensure that the puzzles were helping.
"That's never been done," said Lyketsos.
Without that trial, doctors do not know if patients who do the brain exercises are helped by them, or if people who don't do the exercises and later develop Alzheimer's haven't already begun the process of decline, leading to a lack of interest in doing puzzles in the first place.
Fact or Myth? Some over-the-counter pain relievers make dementia more likely.
Many over-the-counter pain relievers -- belonging to a class known as non-steroidal anti-inflammatory drugs, or NSAIDs (drugs including acetaminophen and ibuprofen) -- have been said to either increase or decrease the likelihood of developing dementia or Alzheimer's disease.
Major studies, however, have disagreed over the result of using NSAIDs to ward off or delay Alzheimer's, which has left doctors recommending using them for pain relief, but not for assisting with Alzheimer's.
At this point, the decision to use these drugs may have nothing to do with Alzheimer's.
"You should take them for reasons that have nothing to do with Alzheimer's disease and dementia," said Karlawish.
Lyketsos of Johns Hopkins has looked at the issue and said that part of the complication may lie in the fact that these drugs might have differing effects at different stages of the disease.
"I think it's an unsorted question," said Lyketsos.
Part of the problem, he explained, is that there's not yet an explanation for why NSAIDs would affect Alzheimer's.
"We're not entirely sure what mechanism these drugs might have aside from being anti-inflammatory," said Lyketsos.
It may be that drugs affect a person based on where they are in their Alzheimer's progression. At this point, he said, the suggestion is that people who have symptoms have no benefit or perhaps some harm from taking NSAIDs.
Meanwhile, he said, studies of patients who have developed nothing seem to show some benefit.
"They suggest that people who take NSAIDs are less likely to get Alzheimer's. They have to be taking these NSAIDs long before these symptoms occur," said Lyketsos.
Patients may be harmed or helped by taking anti-inflammatories, depending where in the disease progression they are. However, even if these drugs might help protect certain patients, tests have not yet been developed that would help doctors identify them.
"Right now, it's hard to know who those people are," said Lyketsos.
Fact or Myth? The artificial sweetener aspartame can cause Alzheimer's.
Answer: Almost definitely a myth
Aspartame and other artificial sweeteners have been accused over the years of causing a number of diseases, including brain tumors, Parkinson's, multiple sclerosis and Alzheimer's.
But there has been little to no evidence to back up these claims, or even enough to warrant looking into them
"I have not seen studies that would lead me to suggest that the FDA should review aspartame and its safety with respect to ... Alzheimer's disease," said Karlawish.
Small said that excessive consumption of artificial sweeteners should be avoided for other health reasons, but not a fear of Alzheimer's.
"We don't have any direct epidemiological evidence to support that," he said.
Advising taking everything in moderation, Small said, "I minimize my brain and body exposure, just in case there is a problem."
While it is difficult to declare this one a myth without a long-term trial, evidence to suggest any truth behind it is sorely lacking.
Fact or Myth? Aluminum use (e.g. in cookware) leads to Alzheimer's.
Answer: Probably a myth
Aluminum, mercury and other heavy metals are often blamed for neurological and mental conditions, because they have been linked to problems in the past.
But when it comes to aluminum, one of the most common metals in our everyday life, evidence to link it to Alzheimer's has been lacking.
"Aluminum is not a cause and certainly not the cause of Alzheimer's, at least not at the levels we're exposed to as part of our daily life," said Karlawish.
Rumors of the deadliness of aluminum have been around for some time. As the rumor-debunking Web site Snopes has noted, it has been blamed for the death of 1920's movie star Rudolph Valentino.
But the legends appear to be ahead of the facts.
"That's an old hypothesis that's not been validated," said Whitehouse.
Although aluminum doesn't appear to be a cause of Alzheimer's, that does not exonerate all heavy metals.
"Lead poisoning contributes to Alzheimer's," said Whitehouse. "Anything you do to your brain when you're a youngster that kills brain cells puts you more at risk for late-in-life dementia."
Fact or Myth? Flu shots can trigger Alzheimer's.
No link has ever been demonstrated between getting a flu shot and developing Alzheimer's disease.
This myth can prove particularly harmful since senior citizens -- the same people who would be most concerned about Alzheimer's -- are asked by the CDC to get a flu shot because of how likely they are to develop complications if they develop the flu.
"Everyone needs to get a flu shot, particularly people with Alzheimer's who have a higher risk of suffering from the flu if they get it," said Karlawish.
Monitoring the safety of the flu vaccine has been done because of concerns about safety raised by the first swine flu vaccine in 1976.
When the first swine flu vaccines were given to 40 million Americans back then, a few hundred people came down with Guillain-Barre Syndrome, a rare disease that affects the nerves. That contributed to some bad publicity, leading the swine flu vaccine program to end in December of that year.
While no definitive link was ever established between Guillain-Barre and the swine flu shots, doctors have carefully monitored the safety of flu vaccines and have not seen any similar problems since.
Fact or Myth? There are two types of memory: short-term and long-term.
Answer: It depends
"It can be as complex or as simple as you want to make it," said Small, noting that dividing memory into short-term and long-term is simply one way to classify it.
But Small noted that memory could be divided into categories such as working memory, where you would hold information you only need now, like a phone number, and emotional memory.
Grisolia noted that in some ways, memory can be thought of in short- and long-term terms.
It may be helpful in understanding Alzheimer's, as short term memories are quickly forgotten if they don't go through the hippocampus.
"Making the bridge is where Alzheimer's gets involved," he said.
With phone numbers, for instance, "a lot of times, by the time the telephone rings, you might not even remember who you're calling," said Grisolia.
And the problems with the hippocampus often cause the memory problems associated with Alzheimer's.
"Those are the areas where Alzheimer's hits first and worst," said Grisolia. "And then the process will start to spread to other areas of the brain."
By looking at different functions of the brain, however, one could find more "types" of memory.
Another type of memory some would consider distinct, Karlawish said, is semantic memory, such as the way you remember what the word "apply" means.
"'Memory' is an omnibus term that captures a variety of cognitive functions," he said.
And the reason this bit of information is impossible to classify is that it is semantic, rather than a fact or myth -- defining memory, like many of the workings of the brain, is more flexible.
"You can chop it up any way you like," said Small.
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