But the trouble is, unlike other serious conditions like cancer—which you can literally see with biopsies—there is no way to definitively prove Alzheimer’s while you’re still alive. Instead, doctors use comprehensive evaluation tools to reach a diagnosis. And that’s an intensive process that can take months or even years, causing frustration and potentially delaying helpful treatments.
What’s more, once you’re given a diagnosis, doctors can only slow the disease’s progression. Currently, there is no cure for Alzheimer’s disease.
For a disease that affects 5.4 million people in the United States, there are still a lot of uncertainties. Read on to discover what we do know—and what researchers still must nail down in order eradicate the condition.
How Alzheimer’s Disease Hurts Your Brain
Alzheimer’s is a progressive brain disorder that slowly destroys your memory and cognitive function.
It’s likely due to harmful changes that occur within your brain: For reasons experts don’t completely understand, bits of a protein called amyloid inside your brain cells start to stick together in waxy clumps called plaques. (Here are 4 surprising things that may actually cause Alzheimer’s.)
Another protein—tau—misfolds like a preschooler’s origami project, forming crumpled growths called tangles in the spaces between neurons, or nerve cells.
These changes interfere with the message-carrying chemicals in your brain, says Keith Fargo, Ph.D., director of scientific programs & Outreach at the Alzheimer’s Association. As a result, messages can’t be received, scrambling your thoughts and erasing your memories.
What’s more, when the connection between the neurons is compromised, those brain cells begin to die. Brain cells in the hippocampus tend to go first, which harms your ability to recall recent experiences or new information, Fargo says.
You might miss important events, repeatedly ask the same questions, or rely on your smartphone for reminders even more than you used to. (Here’s how your phone is stressing you out.)
As damage spreads, tasks that once seemed simple—handling numbers, following a plan or a recipe, remembering the rules of a game—grow difficult, he says. Often, you’ll struggle to find the right words (you might call a watch a hand-clock), keep up with conversations, read, or judge distance. You might be confused about where you are and how you got there, or forget what time, day, or even season it is.
Eventually, you’ll have problems with hygiene, budgets, judgments, and decision-making. Your personality may change—some people become more easily upset, while others turn more talkative, Fargo says.
After an average of about 4 to 8 years after your diagnosis—though sometimes as long as 20—you’ll lose control of your bodily functions, like walking and swallowing.
“Sadly, the current situation is that Alzheimer’s disease always results in death,” Fargo says.
Who Gets Alzheimer’s Disease?
While performing an autopsy back in 1906, a German doctor named Alois Alzheimer first discovered abnormal plaques and tangles in the brain of his middle-aged patient who died with profound memory loss. But it wasn’t until the 1970s when scientists noticed these same abnormalities in the brains of older adults with dementia after they died, that they started to believe those physical manifestations might signal an actual condition.
Before, scientists simply called the symptoms of Alzheimer’s disease senility, and believed that it was a normal part of aging, says Sanjay Asthana, M.D., director of the Wisconsin Alzheimer’s Disease Research Center.
Now, they know it’s a disease that will affect up to 13.8 million people by the year 2050, at an enormous cost—about $236 billion per year in health care, long-term care, and hospice expenses.
In order to help unravel the puzzle, researchers are working hard to learn why some develop Alzheimer’s disease and others don’t. (These 8 daily habits will keep your brain sharp.)
“It’s not a simple disease, where one thing goes wrong,” says Raj Shah, M.D., who’s studied the condition for almost two decades at the Rush Alzheimer’s Disease Center in Chicago. “It probably involves tens or hundreds of factors interacting.”
These may include some common, preventable health conditions, like diabetes and high blood pressure. That’s because they can lead to blood vessel damage, which can make plaques and tangles in the brain more likely to develop, says Demetrius Maraganore, M.D., medical director of the NorthShore University HealthSystem Neurological Institute in Glenview, Illinois.
But some factors associated with Alzheimer’s can’t be changed, such as previous head trauma—including concussions from sports, military service, or accidents—and increasing age. (In fact, 30 former NFL players are donating their brains to science to study the effects of repeated head injury.)
About 90 percent of people with Alzheimer’s disease are age 65 or older, Dr. Asthana says. By the time you reach 85, your odds of having dementia increase to one in three, according tothe Alzheimer’s Association.
But Alzheimer’s disease can strike younger—sometimes as early as your 30s or 40s. Any case diagnosed before age 65 is considered early-onset. Though rare, these cases tend to progress more quickly, Dr. Asthana says.
Is Alzheimer’s Disease Genetic?
Especially in younger patients, family history plays a large role. If an immediate family member—your parent or sibling—has Alzheimer’s disease, your lifetime risk doubles to 20 percent, says Dr. Maraganore, M.D.
Mutations of three genes that affect amyloid production have been linked to early-onset Alzheimer’s disease: APP, presenilin 1, and presenilin 2. If you inherit one or two copies of these mutations, you’ll almost always develop Alzheimer’s disease. (Find out which cancers are genetic.)
Only a few thousand people worldwide have these genes, and most of them have widespread dementia in their families that begins at a younger age, says Fargo. A far more common mutation, called apolipoprotein-E4 or APOE4, doubles your risk of Alzheimer’s disease if you receive one copy from either of your parents.
Many of these cases occur after age 65—commonly known as late-onset Alzheimer’s disease—though people with APOE4 sometimes tend to be diagnosed slightly earlier than those without a genetic predisposition.
If you have two copies, you’re about 10 times as likely to get it, Fargo says. People with a family history of Alzheimer’s can get genetic testing before they have symptoms to see if they carry the certain mutations that predispose them to the brain disease, says Dr. Maraganore.
Still, even if you test positive for the APOE4 mutation, it doesn’t definitively prove you’ll develop Alzheimer’s. In fact, many people with the mutation never develop the disease and many without it do, says Dr. Shah.
How Doctors Diagnose Alzheimer’s Disease
Whether or not a genetic test shows you’re predisposed to Alzheimer’s, you still would need to go through an extensive clinical evaluation in order to be diagnosed with it.
If you start to notice memory problems, make an appointment with your primary care doctor. In most cases, especially if you’re younger than 65, he or she will find another cause of your memory issues, like vitamin B-12 deficiency or sleep apnea. Otherwise, your doctor will refer you to a neurologist, who will be able to delve more deeply into the issue.
First, the doctor will ask you questions about your family history and your symptoms, including how long you’ve had them and how much they affect your daily life, Dr. Shah says.
You’ll probably also take verbal and pencil-and-paper tests, Fargo says: “Do you know what year it is? How many numbers in a row can you remember? Can you draw a clock from memory and put the hands in the right location?”
If these tests and questions reveal memory loss, blood tests and brain scans can rule out other causes such as strokes, bleeding in the brain, or brain tumors.
Your doctor might also order some new tests that may help differentiate Alzheimer’s from other causes of dementia. These include tests that measure amyloid and tau proteins in your spinal fluid, and those that take images of your brain using positron emission tomography (PET) scans.
If no other cause is found for your memory issues, you’ll receive a diagnosis of Alzheimer’s disease. (Find out how your weight might be tanking your memory.)
Though it’s accurate most of the time, the only way doctors can prove Alzheimer’s is by examining the brain after death and finding the hallmark plaques, tangles, and smaller brains due to cell death, Fargo says.
How Do Doctors Treat Alzheimer’s Disease Once It’s Diagnosed?
Currently, medications can only control symptoms and slow the progress of Alzheimer’s disease.
Four drugs called cholinesterase inhibitors prevent the breakdown of important brain chemicals, maintaining better messaging between neurons. Another medication, memantine, regulates levels of glutamate, a neurotransmitter linked to learning and memory.
Unfortunately, most drugs that once showed promise in halting or reversing the course of Alzheimer’s haven’t panned out. In fact, in November, drug company Eli Lilly reportedthat its large trial of a drug called solanezumab—which was supposed to remove amyloid plaques—didn’t change patients’ rates of cognitive decline.
But for Dr. Asthana, every trial—even one that fails—provides information researchers need to move forward.
“It’s a very complex disease. There will not be a single magic bullet or infusion,” he says. “Most people like me believe it to be a combination of treatments that will eventually win the disease.”
That approach will likely include lifestyle changes, which research suggests improve cognitive function in people at risk for developing Alzheimer’s disease.
For instance, a recent Finnish study tested an intense regimen involving exercise, diet changes—including limiting refined sugar and consuming 2.5 to 3 grams of omega-3 fatty acids daily—brain training, and monitoring cardiovascular risk factors like obesity and blood pressure on people at high risk of developing dementia.
The researchers discovered that those who followed the plan for 2 years scored higher on tests of cognitive function than people who just received general health advice. Following a similar blueprint might reduce your risk of Alzheimer’s disease and put you in a better position to benefit from treatments if you do develop it, Dr. Shah says.
What’s more, some experts believe taking drugs like solanezumab earlier in the process might work better.
And other trials are now focusing on a different approach: testing drugs that block an enzyme that plays a role in forming beta-amyloid, and another that attacks tau proteins.
Results of these won’t come out for a few years, but Dr. Shah remains hopeful for a treatment or even a vaccine in his lifetime.
“We have to think about simple and innovative solutions that are going to be usable on a large scale, and hopefully prevent or delay the onset of these symptoms,” he says.