Basics of Alzheimer’s Disease and Dementia
On this page:
- What are the signs and symptoms of dementia?
- What causes dementia?
- What are the different types of dementia?
- How is dementia diagnosed?
- Who can diagnose dementia?
Dementia is the loss of cognitive functioning — thinking, remembering, and reasoning — to such an extent that it interferes with a person's daily life and activities. Some people with dementia cannot control their emotions, and their personalities may change. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person's functioning, to the most severe stage, when the person must depend completely on others for basic activities of living.
Dementia is more common as people grow older (about one-third of all people age 85 or older may have some form of dementia) but it is not a normal part of aging. Many people live into their 90s and beyond without any signs of dementia.
There are several different forms of dementia, including Alzheimer’s disease. A person’s symptoms can vary depending on the type.
What are the signs and symptoms of dementia?
Signs and symptoms of dementia result when once-healthy neurons, or nerve cells, in the brain stop working, lose connections with other brain cells, and die. While everyone loses some neurons as they age, people with dementia experience far greater loss.
The symptoms of dementia can vary and may include:
- Experiencing memory loss, poor judgment, and confusion
- Difficulty speaking, understanding and expressing thoughts, or reading and writing
- Wandering and getting lost in a familiar neighborhood
- Trouble handling money responsibly and paying bills
- Repeating questions
- Using unusual words to refer to familiar objects
- Taking longer to complete normal daily tasks
- Losing interest in normal daily activities or events
- Hallucinating or experiencing delusions or paranoia
- Acting impulsively
- Not caring about other people’s feelings
- Losing balance and problems with movement
People with intellectual and developmental disabilities can also develop dementia as they age, and recognizing their symptoms can be particularly difficult. It’s important to consider a person’s current abilities and to monitor for changes over time that could signal dementia.
What causes dementia?
The causes of Alzheimer’s and related dementias can vary, depending on the types of brain changes that may be taking place. While research has found that some changes in the brain are linked to certain forms of dementia, in most cases, the underlying causes are unknown. Rare genetic mutations may cause dementia in a relatively small number of people.
Although there is no proven prevention, in general, leading a healthy lifestyle may help reduce risk factors that have been associated with these diseases.
What are the different types of dementia?
Various disorders and factors contribute to the development of dementia. Neurodegenerative disorders result in a progressive and irreversible loss of neurons and brain functioning. Currently, there are no cures for these diseases.
Types of dementia include:
- Alzheimer’s disease, the most common dementia diagnosis among older adults. It is caused by changes in the brain, including abnormal buildups of proteins, known as amyloid plaques and tau tangles.
- Frontotemporal dementia, a rare form of dementia that tends to occur in people younger than 60. It is associated with abnormal amounts or forms of the proteins tau and TDP-43.
- Lewy body dementia, a form of dementia caused by abnormal deposits of the protein alpha-synuclein, called Lewy bodies.
- Vascular dementia, a form of dementia caused by conditions that damage blood vessels in the brain or interrupt the flow of blood and oxygen to the brain.
- Mixed dementia, a combination of two or more types of dementia.For example, through autopsy studies involving older adults who had dementia, researchers have identified that many people had a combination of brain changes associated with different forms of dementia.
Scientists are investigating how the underlying disease processes in different forms of dementia start and influence each other. They also continue to explore the variety of disorders and disease processes that contribute to dementia. For example, based on autopsy studies, researchers recently characterized another form of dementia, known as LATE. Further knowledge gains in the underlying causes of dementia will help researchers better understand these conditions and develop more personalized prevention and treatment strategies.
Learn more about how researchers are using neuropathology to address questions and complexities of dementia diseases in Inside the Brain: The Role of Neuropathology in Alzheimer’s Disease Research.
Other conditions that cause dementia-like symptoms can be halted or even reversed with treatment. For example, normal pressure hydrocephalus, an abnormal buildup of cerebrospinal fluid in the brain, often resolves with treatment.
In addition, medical conditions such as stress, anxiety, depression, and delirium can cause serious memory problems that resemble dementia, as can alcohol use disorder and side effects of certain medicines.
Many other conditions can also cause dementia or dementia-like symptoms. These include:
- Creutzfeldt-Jakob disease, a rare brain disorder
- Huntington's disease, an inherited, progressive brain disease
- Chronic traumatic encephalopathy, caused by repeatedtraumatic brain injury
- HIV-associated dementia, a rare disease that occurs when the HIV virus spreads to the brain
The similarity in symptoms of various dementias can make it difficult to get an accurate diagnosis. But a proper diagnosis is important to get appropriate treatment.
How is dementia diagnosed?
To diagnose dementia, doctors first assess whether a person has an underlying, potentially treatable, condition that may relate to cognitive difficulties. A physical exam to measure blood pressure and other vital signs, as well as laboratory tests of blood and other fluids to check levels of various chemicals, hormones, and vitamins, can help uncover or rule out possible causes of symptoms.
A review of a person’s medical and family history can provide important clues about risk for dementia. Typical questions might include asking about whether dementia runs in the family, how and when symptoms began, changes in behavior and personality, and if the person is taking certain medications that might cause or worsen symptoms.
The following procedures also may be used to diagnose dementia:
- Cognitive and neurological tests. These tests are used to assess thinking and physical functioning. These include assessments of memory, problem solving, language skills, and math skills, as well as balance, sensory response, and reflexes.
- Brain scans. These tests can identify strokes, tumors, and other problems that can cause dementia. Scans also identify changes in the brain's structure and function. The most common scans are:
- Computed tomography (CT), which uses X-rays to produce images of the brain and other organs
- Magnetic resonance imaging (MRI), which uses magnetic fields and radio waves to produce detailed images of body structures, including tissues, organs, bones, and nerves
- Positron emission tomography (PET), which uses radiation to provide pictures of brain activity
- Psychiatric evaluation. This evaluation will help determine if depression or another mental health condition is causing or contributing to a person's symptoms.
- Genetic tests. Some dementias are caused by a person’s genes. In these cases, a genetic test can help people know if they are at risk for dementia. It is important to talk with a genetic counselor before and after getting tested, along with family members and the doctor.
- Blood tests. It is now possible for doctors to order a blood test to measure levels of beta-amyloid, a protein that accumulates abnormally in people with Alzheimer’s. Several other blood tests are in development. However, the availability of these diagnostic tests for Alzheimer’s and related dementias is still limited.
Early detection of symptoms is important, as some causes can be treated. However, in many cases, the cause of dementia is unknown and cannot be treated. Still, obtaining an early diagnosis can help with managing the condition and planning ahead.
Sometimes, a person with dementia will agree to donate their brain. Brain donation helps researchers study brain disorders, such as Alzheimer’s disease and related dementias, which affect millions of people. By studying the brains of people who have died, researchers learn more about how types of dementia affect the brain and how we might better treat and prevent them. When donating as part of a research study or to the NIH NeuroBioBank, there is no cost to the family for the donation and an autopsy report.
Who can diagnose dementia?
Visiting a primary care doctor is often the first step for people who are experiencing changes in thinking, movement, or behavior. However, neurologists — doctors who specialize in disorders of the brain and nervous system — are often consulted to diagnose dementia. Geriatric psychiatrists, neuropsychologists, and geriatricians may also be able to diagnose dementia. Your doctor can help you find a specialist.
If a specialist cannot be found in your community, contact the nearest medical school neurology department for a referral. A medical school hospital also may have a dementia clinic that provides expert evaluation. You can also visit the Alzheimer’s Disease Research Centers directory to see if there is an NIA-funded center near you. These centers can help with obtaining a diagnosis and medical management of conditions.
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The NIA ADEAR Center offers information and free print publications about Alzheimer’s and related dementias for families, caregivers, and health professionals. ADEAR Center staff answer telephone, email, and written requests and make referrals to local and national resources.
Explore the Alzheimers.gov portal for information and resources on Alzheimer’s and related dementias from across the federal government.
This content is provided by the NIH National Institute on Aging (NIA). NIA scientists and other experts review this content to ensure it is accurate and up to date.
Content reviewed: July 02, 2021
The symptoms of dementia can vary and may include: Experiencing memory loss, poor judgment, and confusion. Difficulty speaking, understanding and expressing thoughts, or reading and writing. Wandering and getting lost in a familiar neighborhood. Trouble handling money responsibly and paying bills.How do you diagnose dementia diagnosis? ›
How is dementia diagnosed? Doctors diagnose the cause of dementia by asking questions about the person's medical history and doing a physical exam, a mental status exam, and lab and imaging tests. Tests can help the doctor find out if the loss of mental abilities is caused by a condition that can be treated.Is dementia a symptom or diagnosis? ›
Dementia is a term used to describe a group of symptoms affecting memory, thinking and social abilities severely enough to interfere with your daily life. It isn't a specific disease, but several diseases can cause dementia. Though dementia generally involves memory loss, memory loss has different causes.Why is dementia diagnosed? ›
Getting a diagnosis of dementia can give you a better understanding of the condition and what to expect. Timely diagnosis can help you make important decisions about treatment, support and care. You may have been living with memory problems or other symptoms for some time.What are the common symptoms of dementia? ›
- memory loss.
- difficulty concentrating.
- finding it hard to carry out familiar daily tasks, such as getting confused over the correct change when shopping.
- struggling to follow a conversation or find the right word.
- being confused about time and place.
- mood changes.
Dementia can be difficult to diagnose, especially if your symptoms are mild. If the GP has been able to rule out other causes for your symptoms, they'll refer you to a healthcare professional who specialises in diagnosing dementia, such as: a psychiatrist with experience of treating dementia (an old-age psychiatrist)How do you diagnose dementia at home? ›
A new test you can take at home may help detect early symptoms of the disease. The test, known as SAGE, can be taken online or downloaded and completed at your doctor's office. The exam poses a series of questions involving identification of objects, math problems, and thinking tasks.What dementia means? ›
Dementia is not a specific disease but is rather a general term for the impaired ability to remember, think, or make decisions that interferes with doing everyday activities. Alzheimer's disease is the most common type of dementia. Though dementia mostly affects older adults, it is not a part of normal aging.When did dementia become a diagnosis? ›
In the Modern Age, dementia as a diagnosis was initially accepted as a medical term in 1797 by Philippe Pinel (1745–1826), a doctor in France.What is the best treatment for dementia? ›
Donepezil (also known as Aricept), rivastigmine (Exelon) and galantamine (Reminyl) are used to treat the symptoms of mild to moderate Alzheimer's disease. Donepezil is also used to treat more severe Alzheimer's disease.
Although dementia mainly affects older people, it is not an inevitable consequence of ageing. Currently more than 55 million people live with dementia worldwide, and there are nearly 10 million new cases every year.What are the top 10 signs of dementia? ›
- Sign 1: Memory loss that affects day-to-day abilities. ...
- Sign 2: Difficulty performing familiar tasks. ...
- Sign 3: Problems with language. ...
- Sign 4: Disorientation to time and place. ...
- Sign 5: Impaired judgment. ...
- Sign 6: Problems with abstract thinking. ...
- Sign 7: Misplacing things.
Your diagnosis is the basis for any treatment you may receive, from drugs to surgery. An accurate diagnosis is critical to prevent wasting precious time on the wrong course of treatment. The patient plays a crucial role in helping determine the correct diagnosis.What disease causes dementia? ›
- Alzheimer's disease.
- Huntington's disease.
- Vascular dementia.
- Dementia with Lewy bodies.
- Frontotemporal dementia.
- Normal pressure hydrocephalus.
- Creutzfeldt-Jakob disease (prion disease)
- Corticobasal degeneration.
As many as half of people in their 80s have some dementia. Alzheimer's disease is the most common cause of dementia. Between 60%-80% of people with dementia have Alzheimer's. But there are as many as 50 other causes of dementia.What is the dementia test? ›
People with symptoms of dementia are given tests to check their mental abilities, such as memory or thinking. These tests are known as cognitive assessments, and may be done initially by a GP. There are several different tests. A common one used by GPs is the General Practitioner Assessment of Cognition (GPCOG).What is the best test to determine dementia? ›
Mini-Mental Status Examination (MMSE)
The MMSE is the most common test for the screening of dementia. It assesses skills such as reading, writing, orientation and short-term memory.
Blood tests are also used for genetic tests which can reveal, for example, if someone has the defective genes usually present in frontotemporal dementia (Pick's disease) or young onset Alzheimer's.Can dementia be cured? ›
There is currently no "cure" for dementia. In fact, because dementia is caused by different diseases it is unlikely that there will be a single cure for dementia. Research is aimed at finding cures for dementia-causing diseases, such as Alzheimer's disease, frontotemporal dementia and dementia with Lewy bodies.What is the 30 question test for dementia? ›
The Mini–Mental State Examination (MMSE) or Folstein test is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. It is commonly used in medicine and allied health to screen for dementia.
There's no certain way to prevent all types of dementia, as researchers are still investigating how the condition develops. However, there's good evidence that a healthy lifestyle can help reduce your risk of developing dementia when you're older.Does dementia cause death? ›
People often live for years with dementia. While it can be difficult to think of these diseases as terminal, they do eventually lead to death. Caregivers often experience special challenges surrounding the end of life of someone with dementia in part because the disease progression is so unpredictable.Who affects dementia? ›
It mainly affects people over the age of 65. The likelihood of developing dementia increases significantly with age. One in 14 people aged over 65 has dementia. This rises to 1 in 6 for people aged over 80.What is a person with dementia called? ›
'Alzheimer's sufferer' or 'person suffering from dementia' are phrases used to identify an individual who has Alzheimer's, or to make note of the fact that the person in question has dementia.How does dementia affect the brain? ›
In Alzheimer's disease, as neurons are injured and die throughout the brain, connections between networks of neurons may break down, and many brain regions begin to shrink. By the final stages of Alzheimer's, this process—called brain atrophy—is widespread, causing significant loss of brain volume.What are other names for dementia? ›
Dementia is a general term impaired thinking, remembering or reasoning that can affect a person's ability to function safely. The term has been replaced by “major neurocognitive disorder” and “mild cognitive disorder” in medical terminology.Who gets early dementia? ›
Who gets early-onset Alzheimer's? 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.Can dementia improve? ›
While most changes in the brain that cause dementia are permanent and worsen over time, thinking and memory problems caused by the following conditions may improve when the condition is treated or addressed: Depression. Medication side effects.How long can dementia last? ›
Overview of disease progression
The symptoms of Alzheimer's disease worsen over time, although the rate at which the disease progresses varies. On average, a person with Alzheimer's lives four to eight years after diagnosis, but can live as long as 20 years, depending on other factors.
At-home approaches include lifestyle changes, such as regular exercise, good nutrition, maintaining an active social life, doing activities that challenge the mind, and getting a good night's sleep, among others. In this post, we discuss 12 ways to treat dementia at home.
Early diagnosis allows for prompt access to medications and medical attention. Receiving a diagnosis can also help in the management of other symptoms which may accompany the early stage of dementia, such as depression or irritability.What is the 3 word memory test? ›
The Mini-Cog test.
A third test, known as the Mini-Cog, takes 2 to 4 minutes to administer and involves asking patients to recall three words after drawing a picture of a clock. If a patient shows no difficulties recalling the words, it is inferred that he or she does not have dementia.
Introduction: The five-word test (5WT) is a serial verbal memory test with semantic cuing. It is proposed to rapidly evaluate memory of aging people and has previously shown its sensitivity and its specificity in identifying patients with AD.What is the highest stage of dementia? ›
Stage 7: Very severe cognitive decline
Stage 7 is severe Alzheimer's disease or late-stage dementia. Your loved one cannot care for themselves, may experience severe motor and communication impairment, and may lose the ability to speak or walk.
- Alzheimer's Disease. This is the most common type of dementia. ...
- Lewy Body Dementia (or Dementia with Lewy Bodies). Lewy Body Dementia is another very common, yet frequently misdiagnosed, or undiagnosed type of dementia. ...
- Vascular Dementia. ...
- Fronto Temporal Dementia.
- Alzheimer's Disease.
- Vascular Dementia.
- Dementia With Lewy Bodies (DLB)
- Parkinson's Disease Dementia.
- Mixed Dementia.
- Frontotemporal Dementia (FTD)
- Huntington's Disease.
- Creutzfeldt-Jakob Disease.
Dementia is categorised as a Neurocognitive Disorder (NCD) in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The NCD category is then further subdivided into Minor NCD and Major NCD.Are there 8 main types of dementia? ›
- Alzheimer's disease.
- Vascular dementia.
- Lewy Body Disease.
- Frontotemporal dementia.
- Alcohol related dementia.
- Down syndrome and Alzheimer's disease.
- HIV associated dementia.
- Chronic Traumatic Encephalopathy (CTE) dementia.
Donepezil (also known as Aricept), rivastigmine (Exelon) and galantamine (Reminyl) are used to treat the symptoms of mild to moderate Alzheimer's disease. Donepezil is also used to treat more severe Alzheimer's disease.What are the 2 most common types of dementia? ›
The most common types are Alzheimer's disease and vascular dementia. Dementia is most likely to develop in older people over 65 but can occur at a younger age. People with Down syndrome are more likely to develop dementia as they get older, particularly Alzheimer's disease.
Dementia affects about 5 million adults over 65 years old in the United States. A new test you can take at home may help detect early symptoms of the disease. The test, known as SAGE, can be taken online or downloaded and completed at your doctor's office.What is the biggest risk factor for dementia? ›
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.What causes dementia in the brain? ›
Causes of Alzheimer's disease
Alzheimer's disease is the most common type of dementia. Alzheimer's disease is thought to be caused by the abnormal build-up of 2 proteins called amyloid and tau. Deposits of amyloid, called plaques, build up around brain cells. Deposits of tau form "tangles" within brain cells.
Using mass spectrometry, Bateman and colleagues have developed a blood test that is up to 93% accurate at identifying people at risk of Alzheimer's dementia.