What is Alzheimer's? (2023)

Alzheimer's is a type of dementia that affects memory, thinking and behavior. Symptoms eventually grow severe enough to interfere with daily tasks.

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  • Understanding Alzheimer's and dementia
  • Plaques and tangles
  • Symptoms
  • Research
  • Changes in the brain

What is Alzheimer's? (1)Understanding Alzheimer's and dementia

Alzheimer's is the most common cause of dementia, a general term for memory loss and other cognitive abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 60-80% of dementia cases.

Learn more: What is the Difference Between Dementia and Alzheimer's?, What is Dementia, Research and Progress

Alzheimer's is not a normal part of aging. The greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. Alzheimer’s disease is considered to be younger-onset Alzheimer’s if it affects a person under 65. Younger-onset can also be referred to as early-onset Alzheimer’s. People with younger-onset Alzheimer’s can be in the early, middle or late stage of the disease.

Learn more: Younger/Early-Onset Alzheimer's, Risk Factors

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. On average, a person with Alzheimer's lives 4 to 8 years after diagnosis but can live as long as 20 years, depending on other factors.

Learn more: 10 Warning Signs, Stages of Alzheimer's Disease

(Video) What is Alzheimer's disease?

Alzheimer's as a Continuum

Alzheimer's disease progresses in stages, with the severity of symptoms increasing over time.

Select a stage to learn more.

Alzheimer's has no cure, but one treatment — aducanumab (Aduhelm™) — is the first therapy to demonstrate that removing amyloid, one of the hallmarks of Alzheimer’s disease, from the brain is reasonably likely to reduce cognitive and functional decline in people living with early Alzheimer’s. Other treatments 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 underway to find better ways to treat the disease, delay its onset and prevent it from developing.

Learn more: Treatments, Treatment Horizon, Prevention, Clinical Trials

Symptoms of Alzheimer's

The most common early symptom of Alzheimer's is difficulty remembering newly learned information.

Just like the rest of our bodies, our brains change as we age. Most of us eventually notice some slowed thinking and occasional problems with remembering certain things. However, serious memory loss, confusion and other major changes in the way our minds work may be a sign that brain cells are failing.

Alzheimer's changes typically begin in the part of the brain that affects learning. As Alzheimer's advances through the brain it leads to increasingly severe symptoms, including disorientation, mood and behavior changes; deepening confusion about events, time and place; unfounded suspicions about family, friends and professional caregivers; more serious memory loss and behavior changes; and difficulty speaking, swallowing and walking.

(Video) What is Alzheimer's Disease and Why Does it Happen? What Can You Do to Take Preventive Measures?

People with memory loss or other possible signs of Alzheimer’s may find it hard to recognize they have a problem. Signs of dementia may be more obvious to family members or friends. Anyone experiencing dementia-like symptoms should see a doctor as soon as possible. If you need assistance finding a doctor with experience evaluating memory problems, your local Alzheimer's Association can help. Earlier diagnosis and intervention methods are improving dramatically, and treatment options and sources of support can improve quality of life. Two helpful support resources you can tap into are ALZConnected, our message boards and online social networking community, and Alzheimer's Navigator, a web tool that creates customized action plans, based on answers you provide through short, online surveys.

Take our free, online education courses: Understanding Alzheimer's and Dementia and Know the 10 Signs: Early Detection Matters

Help is available

If you or someone you know has been diagnosed with Alzheimer's or another dementia, you are not alone. The Alzheimer's Association is the trusted resource for reliable information, education, referral and support to millions of people affected by the disease.

  • Call our 24/7 Helpline: 800.272.3900
  • Locate your local Alzheimer's Association
  • Use our Virtual Library
  • Go to Alzheimer's Navigator to create customized action plans and connect with local support services

Alzheimer's is not the only cause of memory loss

Many people have trouble with memory — this does NOT mean they have Alzheimer's. There are many different causes of memory loss. If you or someone you know is experiencing symptoms of dementia, it is best to visit a doctor so the cause can be determined.

Learn More

Alzheimer's and the brain

Microscopic changes in the brain begin long before the first signs of memory loss.

The brain has 100 billion nerve cells (neurons). Each nerve cell connects with many others to form communication networks. Groups of nerve cells have special jobs. Some are involved in thinking, learning and remembering. Others help us see, hear and smell.

(Video) How Alzheimer's Changes the Brain

To do their work, brain cells operate like tiny factories. They receive supplies, generate energy, construct equipment and get rid of waste. Cells also process and store information and communicate with other cells. Keeping everything running requires coordination as well as large amounts of fuel and oxygen.

Scientists believe Alzheimer's disease prevents parts of a cell's factory from running well. They are not sure where the trouble starts. But just like a real factory, backups and breakdowns in one system cause problems in other areas. As damage spreads, cells lose their ability to do their jobs and, eventually die, causing irreversible changes in the brain.

The role of plaques and tangles

Two abnormal structures called plaques and tangles are prime suspects in damaging and killing nerve cells.

  1. Plaques are deposits of a protein fragment called beta-amyloid (BAY-tuh AM-uh-loyd) that build up in the spaces between nerve cells.
  2. Tangles are twisted fibers of another protein called tau (rhymes with “wow”) that build up inside cells.

What is Alzheimer's? (2)Though autopsy studies show that most people develop some plaques and tangles as they age, those with Alzheimer’s tend to develop far more and in a predictable pattern, beginning in the areas important for memory before spreading to other regions.

Scientists do not know exactly what role plaques and tangles play in Alzheimer's disease. Most experts believe they somehow play a critical role in blocking communication among nerve cells and disrupting processes that cells need to survive.

It's the destruction and death of nerve cells that causes memory failure, personality changes, problems carrying out daily activities and other symptoms of Alzheimer's disease.

Learn More: Take the Brain Tour

Research and progress

In 1906, German physician Dr. Alois Alzheimer first described "a peculiar disease" — one of profound memory loss and microscopic brain changes — a disease we now know as Alzheimer's.

(Video) What Is Alzheimer's Disease? | Ask The Expert

Today, Alzheimer's is at the forefront of biomedical research. Researchers are working to uncover as many aspects of Alzheimer's disease and other dementias as possible. Some of the most remarkable progress has shed light on how Alzheimer's affects the brain. The hope is this better understanding will lead to new treatments. Many potential approaches are currently under investigation worldwide. Sign up for our weekly E-News to receive updates about Alzheimer’s and dementia care and research.

Learn more: Research and Progress

FAQs

What does Alzheimer's do to you? ›

As Alzheimer's worsens, people experience greater memory loss and other cognitive difficulties. Problems can include wandering and getting lost, trouble handling money and paying bills, repeating questions, taking longer to complete normal daily tasks, and personality and behavior changes.

What are the main causes of Alzheimer's? ›

The causes probably include a combination of age-related changes in the brain, along with genetic, environmental, and lifestyle factors. The importance of any one of these factors in increasing or decreasing the risk of Alzheimer's disease may differ from person to person.

What is Alzheimer In simple words? ›

Alzheimer's disease is a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. In most people with the disease — those with the late-onset type symptoms first appear in their mid-60s.

What is the difference between Alzheimer and dementia? ›

While dementia is a general term, Alzheimer's disease is a specific brain disease. It is marked by symptoms of dementia that gradually get worse over time. Alzheimer's disease first affects the part of the brain associated with learning, so early symptoms often include changes in memory, thinking and reasoning skills.

How long do Alzheimer's patients live? ›

On average, people with Alzheimer's disease live between three and 11 years after diagnosis, but some survive 20 years or more. The degree of impairment at diagnosis can affect life expectancy. Untreated vascular risk factors such as hypertension are associated with a faster rate of progression of Alzheimer's disease.

Can Alzheimer's be prevented? ›

Contents. As the exact cause of Alzheimer's disease is still unknown, there's no certain way to prevent the condition.

Who is at highest risk for Alzheimer's? ›

The greatest known risk factor for Alzheimer's and other dementias is increasing age, but these disorders are not a normal part of aging. While age increases risk, it is not a direct cause of Alzheimer's. Most individuals with the disease are 65 and older. After age 65, the risk of Alzheimer's doubles every five years.

Who is most likely to get Alzheimer's? ›

Who is affected? Alzheimer's disease is most common in people over the age of 65. The risk of Alzheimer's disease and other types of dementia increases with age, affecting an estimated 1 in 14 people over the age of 65 and 1 in every 6 people over the age of 80.

Does Alzheimer's run in families? ›

Many people wonder if Alzheimer's disease runs in the family. A person's chance of having the disease may be higher if he or she has certain genes passed down from a parent. However, having a parent with Alzheimer's does not always mean that someone will develop it.

How is Alzheimer's cured? ›

There's currently no cure for Alzheimer's disease. But there is medicine available that can temporarily reduce the symptoms. Support is also available to help someone with the condition, and their family, cope with everyday life.

How early can Alzheimer's start? ›

For most people with Alzheimer's — those who have the late-onset variety — symptoms first appear in their mid-60s or later. When the disease develops before age 65, it's considered early-onset Alzheimer's, which can begin as early as a person's 30s, although this is rare.

Do Alzheimer's patients suffer? ›

As far as we know, the changes in the brain that occur in Alzheimer's disease and other forms of dementia do not cause pain. However, people with dementia are at increased risk of experiencing pain because they are at increased risk of other things that can cause pain, such as falls, accidents and injuries.

What does Alzheimer's affect the most? ›

It can affect memory, thinking skills and other mental abilities. The exact cause of Alzheimer's disease is not yet fully understood, although a number of things are thought to increase your risk of developing the condition. These include: increasing age.

What are the 4 stages of Alzheimer? ›

Stages of Alzheimer disease
  • Preclinical stage. Changes in the brain begin years before a person shows any signs of the disease. ...
  • Mild, early stage. Symptoms at this stage include mild forgetfulness. ...
  • Moderate, middle stage. This is typically the longest stage, usually lasting many years. ...
  • Severe, late stage.

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