Published on Sep 12, 2023
Alzheimer's is the most common form of dementia, a general term for memory loss and other intellectual abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 60 to 80 percent of dementia cases.
Alzheimer's is a type of dementia that causes problems with memory, thinking and behavior. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks
Alzheimer's is not a normal part of aging, although the greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. But Alzheimer's is not just a disease of old age. Up to 5 percent of people with the disease have early onset Alzheimer's (also known as younger-onset), which often appears when someone is in their 40s or 50s.
Alzheimer's worsens over time. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a conversation and respond to their environment. Alzheimer's is the sixth leading cause of death in the United States. Those with Alzheimer's live an average of eight years after their symptoms become noticeable to others, but survival can range from four to 20 years, depending on age and other health conditions.
Alzheimer's has no current cure, but treatments for symptoms are available and research continues. Although current Alzheimer's treatments cannot stop Alzheimer's from progressing, they can temporarily slow the worsening of dementia symptoms and improve quality of life for those with Alzheimer's and their caregivers. Today, there is a worldwide effort under way to find better ways to treat the disease, delay its onset, and prevent it from developing.
Alzheimer's is not just a disease of old age. Younger-onset (also known as early-onset) Alzheimer's affects people younger than age 65. Up to 5 percent of the more than 5 million Americans with Alzheimer’s have younger-onset.
Many people with early onset are in their 40s and 50s. They have families, careers or are even caregivers themselves when Alzheimer's disease strikes. In the United States, it is estimated that approximately 200,000 people have early onset.
Since health care providers generally don't look for Alzheimer's disease in younger people, getting an accurate diagnosis of early onset Alzheimer's can be a long and frustrating process. Symptoms may be incorrectly attributed to stress or there may be conflicting diagnoses from different health care professionals. People who have early onset Alzheimer's may be in any stage of dementia – early stage, middle stage or late stage. The disease affects each person differently and symptoms will vary.
Have a comprehensive medical evaluation with a doctor who specializes in Alzheimer's disease. Getting a diagnosis involves a medical exam and possibly cognitive tests, a neurological exam and/or brain imaging. Call your local chapter of the Alzheimer's Association for a referral.
Write down symptoms of memory loss or other cognitive difficulties to share with your health care professional
Keep in mind that there is no one test that confirms Alzheimer's disease. A diagnosis is only made after a comprehensive medical evaluation.
Alzheimer's disease is one of the costliest chronic diseases to society.
In 2015, the direct costs to American society of caring for those with Alzheimer's will total an estimated $226 billion, with half of the costs borne by Medicare.
Average per-person Medicare spending for people age 65 or older with Alzheimer's and other dementias is three times higher than for seniors without dementia. Medicaid payments are 19 times higher.
Nearly one in every five Medicare dollars is spent on people with Alzheimer's and other dementias. In 2050, it will be one in every three dollars.
Unless something is done, in 2050, Alzheimer's is projected to cost over $1.1 trillion (in 2015 dollars). This dramatic rise includes a five-fold increase in government spending under Medicare and Medicaid and a nearly five-fold increase in out-of pocket spending
An estimated 5.3 million Americans of all ages have Alzheimer's disease in 2015.
Of the 5.3 million Americans with Alzheimer's, an estimated 5.1 million people are age 65 and older, and approximately 200,000 individuals are under age 65 (younger-onset Alzheimer's).
Almost two-thirds of Americans with Alzheimer's are women. Of the 5.1 million people age 65 and older with Alzheimer's in the United States, 3.2 million are women and 1.9 million are men.
Although there are more non-Hispanic whites living with Alzheimer's and other dementias than people of any other racial or ethnic group in the United States, older African-Americans and Hispanics are more likely than older whites to have Alzheimer's disease and other dementias.
The number of Americans with Alzheimer's disease and other dementias will grow each year as the size and proportion of the U.S. population age 65 and older continue to increase. By 2025, the number of people age 65 and older with Alzheimer's disease is estimated to reach 7.1 million — a 40 percent increase from the 5.1 million age 65 and older affected in 2015. By 2050, the number of people age 65 and older with Alzheimer's disease may nearly triple, from 5.1 million to a projected 13.8 million, barring the development of medical breakthroughs to prevent or cure the disease.
Signs of Alzheimer's
Typical age-related changes
Poor judgment and decision making
Making a bad decision once in a while
Inability to manage a budget
Missing a monthly payment
Losing track of the date or the season
Forgetting which day it is and remembering later
Difficulty having a conversation
Sometimes forgetting which word to use
Misplacing things and being unable to retrace steps to find them
Losing things from time to time
A diagnosis of Alzheimer's allows you to take part in decisions about care, transportation, living options, financial and legal matters. You can also participate in building the right care team and social support network.
Care and support services are available, making it easier for you and your family to live the best life possible with Alzheimer’s or dementia.
"It took my mother having a stress-related heart attack before we quit dismissing my father's progressing dementia to 'senior moments' and got him a proper diagnosis of Alzheimer's. Had we paid attention to the warning signs of this disease, a lot of prevention could have been in place."-Brent
Your doctor will evaluate your overall health and identify any conditions that could affect how well your mind is working. Your doctor may refer you to a specialist such as a:
Neurologist– specializes in diseases of the brain and nervous system
Psychiatrist – specializes in disorders that affect mood or the way the mind works
Psychologist – has special training in testing memory and other mental functions
Geriatrician – specializes in the care of older adults and Alzheimer's disease
Alzheimer's disease typically progresses slowly in three general stages — mild (early-stage), moderate (middle-stage), and severe (late-stage). Since Alzheimer's affects people in different ways, each person will experience symptoms - or progress through Alzheimer's stages - differently.
Overview of disease progression:
Mild Alzheimer's (early-stage)
Moderate Alzheimer's (middle-stage)
Severe Alzheimer's (late-stage)
Although the onset of Alzheimer's disease cannot yet be stopped or reversed, an early diagnosis can allow a person the opportunity to live well with the disease for as long as possible and plan for the future.In the early stages of Alzheimer's, a person may function independently. He or she may still drive, work and be part of social activities. Despite this, the person may feel as if he or she is having memory lapses, such as forgetting familiar words or the location of everyday objects.
Friends, family or neighbors begin to notice difficulties. During a detailed medical interview, doctors may be able to detect problems in memory or concentration.
Common difficulties include:
Problems coming up with the right word or name
Trouble remembering names when introduced to new people
Having greater difficulty performing tasks in social or work settings
Forgetting material that one has just read
Losing or misplacing a valuable object
Increasing trouble with planning or organizing
During the moderate stage of Alzheimer's, individuals may have greater difficulty performing tasks such as paying bills, but they may still remember significant details about their life.
Moderate Alzheimer's is typically the longest stage and can last for many years. As the disease progresses, the person with Alzheimer's will require a greater level of care.
You may notice the person with Alzheimer's confusing words, getting frustrated or angry, or acting in unexpected ways, such as refusing to bathe. Damage to nerve cells in the brain can make it difficult to express thoughts and perform routine tasks.
At this point, symptoms will be noticeable to others and may include:
Forgetfulness of events or about one's own personal history
Feeling moody or withdrawn, especially in socially or mentally challenging situations
Being unable to recall their own address or telephone number or the high school or college from which they graduated
Confusion about where they are or what day it is
The need for help choosing proper clothing for the season or the occasion
Trouble controlling bladder and bowels in some individuals
Changes in sleep patterns, such as sleeping during the day and becoming restless at night
An increased risk of wandering and becoming lost
Personality and behavioral changes, including suspiciousness and delusions or compulsive, repetitive behavior like hand-wringing or tissue shredding
Late-stage care decisions can be some of the hardest families face. Connect with other caregivers who have been through the process on our online message boards and get helpful resources in our Caregiver Center.
In the final stage of this disease, individuals lose the ability to respond to their environment, to carry on a conversation and, eventually, to control movement. They may still say words or phrases, but communicating pain becomes difficult. As memory and cognitive skills continue to worsen, personality changes may take place and individuals need extensive help with daily activities.
At this stage, individuals may:
Require full-time, around-the-clock assistance with daily personal care
Lose awareness of recent experiences as well as of their surroundings
Require high levels of assistance with daily activities and personal care
Experience changes in physical abilities, including the ability to walk, sit and, eventually, swallow
Have increasing difficulty communicating
Become vulnerable to infections, especially pneumonia
Genetic tests are available for both APOE-e4 and the rare genes that directly cause Alzheimer’s. However, health professionals do not currently recommend routine genetic testing for Alzheimer’s disease. Testing for APOE-e4 is sometimes included as a part of research studies.
Risk genes increase the likelihood of developing a disease, but do not guarantee it will happen. Scientists have so far identified several risk genes implicated in Alzheimer's disease. The risk gene with the strongest influence is called Apo lipoprotein E-e4 (APOE-e4). Scientists estimate that APOE-e4 may be a factor in 20 to 25 percent of Alzheimer's cases.
APOE-e4 is one of three common forms of the APOE gene; the others are APOE-e2 and APOE-e3. Everyone inherits a copy of some form of APOE from each parent. Those who inherit APOE-e4 from one parent have an increased risk of Alzheimer’s. Those who inherit APOE-e4 from both parents have an even higher risk, but not a certainty.
Scientists are not yet certain how APOE-e4 increases risk. In addition to raising risk, APOE-e4 may tend to make Alzheimer's symptoms appear at a younger age than usual .Deterministic genes directly cause a disease, guaranteeing that anyone who inherits them will develop the disorder. Scientists have discovered variations that directly cause Alzheimer’s disease in the genes coding three proteins: amyloid precursor protein (APP), presenilin-1 (PS-1) and presenilin-2 (PS-2).
When Alzheimer’s disease is caused by these deterministic variations, it is called “autosomal dominant Alzheimer’s disease (ADAD)” or “familial Alzheimer’s disease,” and many family members in multiple generations are affected. Symptoms nearly always develop before age 60, and may appear as early as a person's 30s or 40s. Deterministic Alzheimer's variations have been found in only a few hundred extended families worldwide. True familial Alzheimer’s accounts for less than 5 percent of cases.
There is no single test that can show whether a person has Alzheimer's. While physicians can almost always determine if a person has dementia, it may be difficult to determine the exact cause.
Diagnosing Alzheimer's requires careful medical evaluation, including:
A thorough medical history
Mental status testing
A physical and neurological exam
Tests (such as blood tests and brain imaging) to rule out other causes of dementia-like symptoms
People with memory loss or other possible warning signs of Alzheimer's may find it hard to recognize they have a problem and may resist following up on their symptoms. Signs of dementia may be more obvious to family members or friends.
Having trouble with memory does not mean you have Alzheimer's. Many health issues can cause problems with memory and thinking. When dementia-like symptoms are caused by treatable conditions — such as depression, drug interactions, thyroid problems, excess use of alcohol or certain vitamin deficiencies — they may be reversed during the medical workup, your health care provider will review your medical history. He or she will want to know about any current and past illnesses, as well as any medications you are taking. The doctor will also ask about key medical conditions affecting other family members, including whether they may have had Alzheimer's disease or related dementias.
The science of Alzheimer's has advanced to show potential underlying drivers of the disease. And we have candidate drugs we can test because of this basic science knowledge." - Richard Mohs, Ph.D.
A worldwide quest is under way to find new treatments to stop, slow or even prevent Alzheimer's. Because new drugs take years to produce from concept to market—and because drugs that seem promising in early-stage studies may not work as hoped in large-scale trials—it is critical that Alzheimer's and related dementias research continue to accelerate. To ensure that the effort to find better treatments receives the focus it deserves, the Alzheimer's Association funds researchers looking at new treatment strategies and advocates for more federal funding of Alzheimer's research.
Currently, there are five FDA-approved Alzheimer's drugs that treat the symptoms of Alzheimer's — temporarily helping memory and thinking problems in about half of the people who take them. But these medications do not treat the underlying causes of Alzheimer's.
In contrast, many of the new drugs in development aim to modify the disease process itself, by impacting one or more of the many wide-ranging brain changes that Alzheimer's causes. These changes offer potential "targets" for new drugs to stop or slow the progress of the disease. Many researchers believe successful treatment will eventually involve a "cocktail" of medications aimed at several targets, similar to current state-of-the-art treatments for many cancers and AIDS. Sign up for our weekly e-news and stay up-to-date on the latest advances in Alzheimer's treatments, care and research.
Over the last 30 years, researchers have made remarkable progress in understanding healthy brain function and what goes wrong in Alzheimer's disease. The following are examples of promising targets for next-generation drug therapies under investigation in current research studies:
Beta-amyloid is the chief component of plaques, one hallmark Alzheimer's brain abnormality. Scientists now have a detailed understanding of how this protein fragment is clipped from its parent compound amyloid precursor protein (APP) by two enzymes — beta-secretase and gamma-secretase. Researchers are developing medications aimed at virtually every point in amyloid processing. This includes blocking activity of both enzymes; preventing the beta-amyloid fragments from clumping into plaques; and even using antibodies against beta-amyloid to clear it from the brain. Several clinical trials of investigational drugs targeting beta-amyloid are included below in the key clinical trial summary.
Tau protein is the chief component of tangles, the other hallmark brain abnormality. Researchers are investigating strategies to keep tau molecules from collapsing and twisting into tangles, a process that destroys a vital cell transport system.
Inflammation is another key Alzheimer's brain abnormality. Scientists have learned a great deal about molecules involved in the body's overall inflammatory response and are working to better understand specific aspects of inflammation most active in the brain. These insights may point to novel anti-inflammatory treatments for Alzheimer's disease.
Insulin resistance and the way brain cells process insulin may be linked to Alzheimer's disease. Researchers are exploring the role of insulin in the brain and closely related questions of how brain cells use sugar and produce energy. These investigations may reveal strategies to support cell function and stave off Alzheimer-related changes.
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