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What to Know About Alzheimer's Disease

Early symptoms, warning signs and stages of the condition — plus, what the latest drug news means

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Andrew Brookes/Getty Images

It's perfectly normal to occasionally forget someone's name or where you parked the car. But for many older adults, those moments of forgetfulness foster a deeper fear: Could they be an early sign of Alzheimer's disease?

Alzheimer's is a progressive, fatal brain disorder that slowly destroys memory and thinking skills, eventually affecting your ability to carry on a conversation and function independently.

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About 5.8 million Americans live with the illness, according to the Centers for Disease Control and Prevention (CDC). And that number is projected to nearly triple over the next few decades, to 14 million people by 2060.

Alzheimer's disease and dementia are not the same. Dementia is a catch-all term that describes any cognitive decline severe enough to interfere with daily living. Alzheimer's is the most common type of dementia. It's specifically characterized by the buildup of amyloid plaques and tangled fibers called tau in the brain and by a loss of connections between nerve cells.

In most people with the disease, symptoms first appear after age 60. But Alzheimer's is not just a condition of old age. Approximately 200,000 Americans under age 65 have the disease (also known as early-onset Alzheimer's).

Although medical management can improve quality of life, there is no known cure for Alzheimer's. It is the sixth leading cause of death among U.S. adults and the fifth leading cause of death among adults 65 and older.

To help address this enormous health challenge, federal funding for dementia and Alzheimer's disease research has surged in recent years, to $3.1 billion in 2020. Experts say many promising diagnostics and treatments are being developed and tested.

Risk factors to know

Age Advancing age does not cause Alzheimer's, but it is the greatest known risk factor. About 1 in 9 people 65 and older have Alzheimer's dementia. After age 65, the risk doubles every five years, and about a third of people older than 85 have the disease. Scientists are still studying how age-related changes in the brain may contribute to Alzheimer's progression.

Genetics Anyone who has a parent, brother or sister with Alzheimer's is nearly twice as likely to develop the disease, and those who have two first-degree relatives with Alzheimer's have almost four times the risk. Even if your parents and siblings don't have the illness, having second- or third-degree relatives with Alzheimer's increases your risk, according to a 2019 study published in Neurology. Researchers have not found a specific gene that directly causes Alzheimer's, but they have identified a gene called APOE e4 that raises risk. It occurs in about 40 percent of people who have the disease.

Race and ethnicity African Americans are about twice as likely to develop Alzheimer's as Caucasians; Hispanics are about 1.5 times more likely. Their greater risk may be related to these groups’ higher rates of cardiovascular disease, researchers say.

Poor cardiovascular health A growing body of evidence has linked the risk of developing Alzheimer's to many conditions that damage the heart and blood vessels, including heart disease, diabetes, stroke, high blood pressure and high cholesterol. On the plus side, taking control of your health may reduce your odds of dementia. Some studies have found that taking medication to control blood pressure and cholesterol can reduce dementia risk.

Ask the Expert

Q&A with Beth Kallmyer, vice president of Care and Support for the Alzheimer's Association

What are some misconceptions about Alzheimer's disease?

People think that Alzheimer's is only about memory loss. While memory loss is an early symptom, other symptoms include loss of judgment, loss of executive function and the inability to track not just conversation but the actual steps in a process of a regular habit, like getting dressed or making breakfast.

The other really big misconception is that once you have Alzheimer's, you can't communicate and you don't remember anybody. It's not something that happens all at once. Now that science has progressed, people can be diagnosed in the very early stages. It might not be obvious they have the disease.

How can I tell if it's Alzheimer's disease or just normal age-related memory loss?

Normal forgetfulness happens to all of us. What you should be concerned about is if you have one of those forgetful moments and you can't track back in time. So if you lost your keys and then you eventually find them in the den, you might say, “Oh, yes, I came in here to water that plant.” But if you have no memory of putting them there and you think someone moved them, that's more of a cause for concern. Another reason for concern is if you're forgetting really important things. So, for example, someone who always remembers their grandchildren's birthdays can't remember them. Or someone who never misses appointments starts missing them. What you want to look for is a significant change in normal behavior.

How can I lower my risk of Alzheimer's disease?

A growing body of research shows you can make lifestyle changes to reduce your risk. Exercise. Eat right. Manage your cholesterol and blood pressure numbers. Stay engaged. It may not sound exciting, but there's good evidence to show those things make a difference.

These Q&As have been edited for length and clarity.

Early symptoms

Here are some early warning signs of Alzheimer's disease, according to the Alzheimer's Association:

  • Difficulty with everyday tasks Struggling to do things that were once easy, such as paying bills, remembering the rules of a familiar game or following a favorite recipe

  • Communication problems Asking the same question again and again, getting lost during a conversation or forgetting the name of a close friend or relative

  • Confusion about time or place Losing track of dates, seasons and the passage of time; getting lost while driving to a familiar location; or forgetting where you are

  • Misplacing things or putting them in unusual places Losing things or putting them somewhere odd and then being unable to retrace your steps to find them; people with Alzheimer's may accuse others of stealing, especially as the disease progresses.

  • Mood or personality changes Withdrawal from social activities, acting quieter or more argumentative than normal or becoming confused, suspicious, depressed, fearful or anxious

Getting a diagnosis

If you or a loved one is experiencing memory loss, it's important to see a doctor, says Michael Weiner, M.D., principal investigator of the Alzheimer's Disease Neuroimaging Initiative, the largest observational study of Alzheimer's disease in the world.

It's possible that your symptoms may not be due to Alzheimer's but to some other treatable condition, like thyroid disease or a vitamin deficiency, Weiner says.

If it is Alzheimer's, an early diagnosis gives you more access to treatment options and a chance to make lifestyle changes, such as controlling blood pressure and exercising, that may help preserve your cognitive function. It also allows you more time to plan for the future and enjoy meaningful activities with the people who are important to you.

Right now, the gold-standard method to diagnose Alzheimer's is a type of scan that measures amyloid deposits in the brain. Another option is a spinal tap that can gauge amyloid levels in the fluid surrounding the brain and spinal cord.

These tests aren't used to diagnose most patients, though, because they're expensive and often not covered by insurance. Instead, most physicians use medical history, other types of brain imaging, memory tests, and physical and neurological exams to make a clinical diagnosis.

New blood tests may help with early detection

Among the most exciting news in the Alzheimer's field is the development of simple blood tests to detect the disease, reducing the need for an expensive brain scan or invasive spinal tap. The new tests also potentially make it possible to detect the changes in the brain before symptoms appear.

One test, called the PrecivityAD, is already available in most of the U.S. It went on the market in late 2020, after being approved under the federal government's general rules for commercial labs, but it does not yet have authorization from the Food and Drug Administration (FDA). The test detects the presence of beta-amyloid plaques in the brain and is meant to be used by health providers who are evaluating people 60 and older who have cognitive or memory problems.

Several other tests are also close to market, Weiner says. He predicts that a variety of tests to help diagnose Alzheimer's will be available to patients in the next few years.


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Early detection of Alzheimer's is key because the brain may start changing as early as 20 years before symptoms appear, says Rudolph Tanzi, a neuroscientist at Harvard Medical School and codirector of the McCance Center for Brain Health at Massachusetts General Hospital.

Many researchers believe that intervening before symptoms develop offers the greatest potential for halting or delaying disease progression.

Right now “we don't diagnose Alzheimer's until the brain has degenerated to the point of dysfunction ... that has to change,” Tanzi says. “Once you have symptoms, the brain is on fire with neuroinflammation. ... We have to become as proactive about Alzheimer's disease as we are about heart disease, diabetes and other age-related diseases.”

Stages of Alzheimer's disease

Although everyone experiences the condition differently, understanding the trajectory of it can help patients and their caregivers know what to expect. Alzheimer's typically progresses in three general phases:

  • Early stage The person still functions independently. He may still drive, work and be part of social activities. But the individual forgets familiar words or the location of everyday objects with increasing frequency. Symptoms may not be widely apparent, but family and close friends may notice early signs and voice concern.

  • Middle stage The individual can still participate in daily activities but may need extra help. She gets confused more easily or experiences personality changes, like getting angry or acting out in unexpected ways. During this stage it's important to determine what the person living with Alzheimer's still enjoys doing and find ways to engage her in those activities. You want to help the individual maintain the best quality of life for as long as possible.

  • Late stage The patient loses the ability to respond to his environment, to carry on a conversation and, eventually, to control movement. As memory and cognitive skills worsen, significant personality changes take place and extensive care is required. The end stage of Alzheimer's can last for several weeks or years; it can be extremely demanding and emotionally draining for families.

Current treatments

In June 2021 the FDA approved the first new treatment for Alzheimer's in more than a decade. Called aducanumab (brand name Aduhelm), it's a monoclonal antibody drug that could potentially slow the progression of the disease.

Aduhelm is not a cure for Alzheimer's and does not reverse it. But data show that the drug can break up sticky plaques in the brain that are a hallmark of the disease. If the drug can help remove those plaques, it may help slow the rate of cognitive decline in people in the early stages, experts say.

The FDA's approval, however, was conditional. The drug's maker, Biogen, will need to complete a large clinical trial to confirm that removing the plaque has cognitive benefits, the agency said. If the study fails, as some experts are quick to point out it could, the FDA has the authority to rescind its approval.

For patients and their families, Aduhelm offers hope, but it's unclear how many people will benefit initially. The therapy, which is a monthly infusion, is expected to cost $56,000 a year, and it's not yet known whether Medicare and private insurance will cover it.

Other FDA-approved medications can help manage the symptoms of Alzheimer's. Drugs called cholinesterase inhibitors — including galantamine (Razadyne), rivastigmine (Exelon) and donepezil (Aricept) -— may help with short-term memory loss or confusion for a limited time.

For those with moderate or severe Alzheimer's, a drug called memantine (Namenda) may help some to perform daily functions for longer than without the medication. The FDA has also approved a combination of donepezil and memantine (Namzaric), which is taken as a capsule.

Another medication, called Belsomra, is authorized to help with insomnia, and sometimes other drugs, including antidepressants, are prescribed to help control behavioral symptoms.

On the horizon: New treatments show promise

In recent years tremendous gains have been made in understanding the basic biology of Alzheimer's, including how brain cells work and what goes wrong in the brain to cause the disease, says Heather Snyder, vice president of medical and scientific relations at the Alzheimer's Association.

"As our understanding of the underlying biology has increased, we are seeing many new interventions moving into clinical trials,” she says.

Several new drugs in development have the potential to be game changers, Snyder says. Some of the most promising are other monoclonal antibody drugs, with names like gantenerumab, lecanemab (BAN2401) and donanemab. Like Aduhelm, they're designed to stick to the molecules that form plaques in the brain and mark them, so that the immune system can recognize them and clear them out.

Donanemab had impressive early results. In a study of 257 patients whose brain scans showed Alzheimer's, those who took the drug had a 32 percent slower rate of decline over a two-year period than those who received a placebo.

Dozens of other drugs that use different mechanisms for stopping the disease are also being tested, Snyder says.

Because Alzheimer's is so complex, experts say there may never be just one drug or intervention that will cure it. Instead, Snyder says, “it's likely going to take a combination approach of lifestyle interventions and medications."

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Patient perspective: What I learned from my Alzheimer's disease diagnosis

"I was always really organized and meticulous. When I was age 50 or 52, I started to notice things changing. I couldn't sleep. I was losing things and having trouble focusing. At home, I was having difficulty with finances, keeping things organized and doing the laundry. Everything seemed monumental. At first, doctors blamed it on menopause, anxiety or depression. It took almost 10 years and three different doctors, but, finally, I was diagnosed with early-onset Alzheimer's. My very first reaction was relief – thank God I'm not losing my mind. I felt validated and, finally, respected. After the relief it was truly a grieving process. I felt very angry and frustrated and in disbelief for probably six months. Then I got involved with the Alzheimer's Association. Meeting other people with the same disease brought me hope and the realization that I was not alone. I felt empowered to do what I could to stop this disease – to raise awareness, to raise funds. I also found a voice through advocacy. I'm not quiet anymore like I used to be. I want to show the world you can have a productive and meaningful life while living with Alzheimer's.”

—Tammy Maida, 64, a former nurse in San Jose, California, and a national early-stage adviser for the Alzheimer's Association

The following experts provided content for this story:

  • Heather Snyder, vice president of medical and scientific relations at the Alzheimer's Association

  • Michael Weiner, M.D., principal investigator of the Alzheimer's Disease Neuroimaging Initiative, the largest observational study of Alzheimer's disease

  • Rudolph Tanzi, M.D., a neuroscientist at Harvard Medical School and codirector of the McCance Center for Brain Health at Massachusetts General Hospital


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