Dementia

What is dementia?

Dementia is a term used to describe a range of neurological conditions affecting the brain that get worse over time. In dementia, loss of the ability to think, remember, and reason are enough to affect daily life and activities. Some people with dementia can't control their emotions and other behaviors, and their personality may change. 

Although up to half of all people 85 or older may have some type of dementia, it’s not a normal part of aging. Many people live into their 90s and beyond without any signs of dementia. 

Dementia usually happens when certain proteins accumulate and clump in the brain. When this happens, brain cells don’t work properly and can slowly die over time.

Symptoms of dementia

The symptoms of dementia depend on the type of dementia a person has and which areas of their brain are affected. Symptoms may include:

Types of dementia

Types of dementia include: 

Alzheimer’s disease (AD)

Alzheimer's disease (AD) is the most common dementia diagnosis. In AD, pieces of a protein called amyloid can clump together between brain cells, and another protein called tau can form tangles inside brain cells. These and other changes—such as swelling and irritation (inflammation) and problems with blood vessels in the brain—slowly damage brain cells and their connections. Over time, this damage leads to memory loss and other problems with thinking and behavior.

Some medicines, including newer treatments that target the amyloid protein, may help slow the worsening of symptoms for some people, but no current medicines can stop or cure AD.

Frontotemporal dementia (FTD)

Frontotemporal dementia (FTD) affects parts of the brain that make decisions, create memories, and understand language. Many brain disorders are named after the brain regions affected. For FTD, these are the frontal (front of the brain) and temporal (sides of the brain) regions. The term frontotemporal lobar degeneration (FTLD) is sometimes used to describe the underlying brain disease of people with FTD.

FTD can affect a person’s behavior, emotions, and ability to make decisions, perform tasks, and control movement. FTD can also affect memory, speech, and how people understand words, recognize objects, and control their feelings. Changes gradually worsen over time.

FTD has multiple types:

1. Behavioral variant frontotemporal dementia (bvFTD) usually doesn’t affect memory but causes changes in a person’s behavior, judgment, and personality. People with bvFTD may seem uninterested or less caring than their usual self. Their behavior can seem inappropriate and is sometimes mistaken for a mental health condition.
2. Primary progressive aphasia (PPA) causes changes in the ability to speak, understand words, express thoughts, write, and read. For example, people may have a hard time finding words or remembering the names of objects. Symptoms get worse over time, and eventually a person with PPA may become unable to understand written or spoken language.
3. Corticobasal degeneration (CBD) mainly affects a person’s movement, such as doing routine tasks with their hands. As CBD gets worse, behavior and language problems usually develop. But these symptoms may appear in a different order. CBD is named after the brain regions affected: the outer part of the brain (cerebral cortex) and the part of the brain that helps control movement (basal ganglia).
4. FTD-ALS combines typical behavioral and language symptoms of FTD along with symptoms of amyotrophic lateral sclerosis (ALS). They include loss of muscle control affecting walking, swallowing, and talking.
5. Progressive supranuclear palsy (PSP) is a rare brain disorder that affects coordination and balance, eye movements, thinking, and behavior. Over time, PSP can interfere with a person’s everyday activities and independence. People with PSP have abnormal clumping of a protein called tau in their brain. PSP can at first be mistaken for Parkinsons's disease (PD) due to its similar symptoms. Compared to PD, PSP often causes earlier problems with balance and walking, more frequent falls, greater stiffness and earlier changes in thinking and behavior.

Lewy body dementia (LBD)

Lewy body dementia (LBD) is one of the most common types of dementia, causing problems with thinking, movement, behavior, and mood. Symptoms usually begin after age 50, but they can happen earlier in life. Lewy bodies are abnormal clumps of proteins called alpha-synuclein that build up inside brain cells. These clumps stop brain cells from working properly and can cause the cells to die.

LBD has two types:

1. Dementia with Lewy bodies (DLB) affects different parts of the brain that control thinking, behavior, sleep and movement. People with DLB often have sleep problems and a trouble with the sense of smell. They may also see things that aren’t there (hallucinations), have memory loss, trouble making decisions, episodes of confusion, and difficulty moving due to Parkinson’s disease (PD)-like symptoms.
2. PD dementia happens when PD-like movement problems come first. Later, problems with memory, language, decision-making, and thinking clearly can develop. Not everyone with PD will develop dementia.

Mixed dementia

Mixed dementia refers to dementia thought to be connected to a mixture of changes in the brain. For example, a person might have evidence of changes traditionally associated with both Alzheimer’s and vascular dementia.

Vascular brain conditions and dementia

Vascular contributions to cognitive impairment and dementia (VCID) happen when blood doesn’t flow well to a person’s brain, causing changes to memory, thinking, and behavior. Many conditions can cause VCID or make it worse, including strokes, irregular heartbeats, high blood pressure, diabetes, or high cholesterol.

There are several types of VCID:

• Vascular dementia is a serious type of VCID that causes memory loss and ongoing problems with daily life. It is caused by damage to the brain from conditions that affect the heart and blood vessels, which carry oxygen-rich blood to the body and brain.
• Vascular cognitive impairment causes small but noticeable changes in language, attention, and the ability to think clearly. These changes don’t really affect daily life but get worse slowly over time.
• Swelling of blood vessels (vasculitis) is inflammation that happens when the body’s immune system attacks the blood vessels by mistake. This happens because of an infection, a medicine, another disease, or often, an unknown cause.
• Post-stroke dementia happens after a person has a stroke, causing problems with memory, thinking, language, and behavior that interfere with daily life. A person’s risk of having dementia is higher if their stroke affected both sides of their brain. Even strokes that don't cause any noticeable symptoms can make a person more likely to have dementia.
• Multi-infarct dementia happens when many small strokes affect different parts of the brain. This may affect language or other brain functions, depending on what part of the brain has been damaged. 
• CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is a rare, inherited condition that damages small blood vessels in the brain and reduces blood flow. It can cause migraine headaches, strokes, problems with thinking and memory, and changes in mood or behavior.
• Subcortical vascular dementia is dementia caused by damage or narrowing in very small blood vessels in the brain that affect how parts of the brain communicate with each other. It can cause problems with short-term memory, planning, attention, decision making, and behavior.
• Cerebral amyloid angiopathy is a disease of the small blood vessels in the brain in which a protein called amyloid builds up in the walls of blood vessels. Unlike amyloid changes in AD, in cerebral amyloid angiopathy, the clumps collect in blood vessels rather than between brain cells. This buildup can weaken the vessels and cause bleeding in the brain—which can lead to problems with thinking, movement, and other brain functions.

Other conditions that can cause dementia or dementia-like symptoms

• Buildup of spinal fluid in the brain (normal pressure hydrocephalus)
• Low levels of vitamin B1 (thiamine)
• Bleeding between the brain's surface and its outer covering (subdural hematoma)
• Brain tumors
• Infections around the brain
• Argyrophilic grain disease is one of several conditions caused by abnormal clumps of tau protein in brain cells. It usually affects older adults, causing mild memory and thinking problems.
• Creutzfeldt-Jakob disease is rare brain condition that happens when improperly shaped proteins called prions damage the brain. People with this condition have problems with thinking, memory, movement, and behavior. Symptoms usually get worse quickly.
• Chronic traumatic encephalopathy (CTE) is a brain disease that can happen in some people after many hits to the head over time. Severe forms of CTE can cause dementia symptoms.
• Huntington's disease is an inherited brain condition that causes problems with movement, thinking, and behavior. Symptoms usually get worse over time.
• HIV-associated dementia happens when HIV, the virus that causes AIDS, damages the brain, causing problems with memory and thinking.
• Multiple sclerosis (MS) happens when a person’s immune system damages nerves, causing problems with movement, feeling, and thinking. In MS, dementia-like symptoms usually have mild effects on thinking, attention, and memory.
• Parkinson’s disease (PD) is a brain condition that mainly affects a person’s body movement, causing shaking, stiffness, and slowness. In PD, dementia symptoms can include slower thinking, trouble focusing, memory problems, confusion, and seeing things that aren’t there.
• Wilson's disease is a rare inherited condition in which too much copper from foods a person eats build up in their body, especially in the liver and brain. This extra copper can damage the brain, causing problems with thinking, memory, and behavior.

Who is more likely to get dementia?

Genetic variants (also called mutations) in some specific genes can cause dementia. But most people with dementia don’t have any of these gene changes, and the cause(s) of their dementia are unknown.

Mild cognitive impairment (MCI) happens when a person has more than normal age-related memory changes that are not as serious as dementia. A person with MCI may have a higher risk of developing dementia than a person who doesn’t have MCI. Symptoms of MCI can include:

• Mild memory loss
• Problems planning and staying organized
• Trouble finding words
• Frequently losing or misplacing things
• Forgetting names, conversations, and events

Risk factors

A risk factor is something that increases the chance that someone will develop a health problem. But having a risk factor doesn't guarantee whether a person will develop dementia or not.

These risk factors may increase a person's chance of getting dementia:

• Being older
• High blood pressure
• Stroke
• Alcohol use
• Problems with blood vessels, such as hardening of the arteries 
• Diabetes
• Down syndrome
• Family history of dementia, such as inherited gene changes
• Brain injuries
• Parkinson's disease
• Smoking

How is dementia diagnosed and treated?

Diagnosing dementia

To diagnose dementia, doctors first check for other treatable conditions that could cause problems with thinking or memory. If these tests are negative, in many cases, doctors cannot tell exactly which type of dementia a person has.

Tests may include:

• Medical histories and physical exams: Doctors ask questions about a person's medical and family history to identify health issues that might cause dementia symptoms. Some conditions may be treatable.
• Nervous system tests: Testing balance, reflexes, and other body functions can help doctors identify brain diseases, including dementia. Tests that measure electrical activity in the brain (electroencephalograms, or EEGs) can detect brain changes linked to diseases including dementia.
• Brain scans: Doctors use brain scans such as CT (computed tomography) and MRI (magnetic resonance imaging) to check for problems like tumors, strokes, or bleeding that could cause memory or thinking problems. If these are not found, doctors can rule them out as a cause of dementia symptoms. PET (positron-emission tomography) is a special scan that can find changes in brain activity that are common in dementia, including abnormal amounts of amyloid and tau protein typical of some types of dementia.
• Cognitive and neuropsychological tests: These paper-and-pencil or verbal tests check memory and thinking skills.
• Laboratory tests: Testing a person's blood and other fluids, and checking levels of various chemicals, hormones, and vitamins, can find conditions that may contribute to dementia.
• Genetic testing: Genetic tests that read DNA can tell whether a person is at higher risk for dementia.
• Psychiatric evaluation: These tests check a person’s mental health to see if symptoms are caused by depression or another condition instead of dementia.  

Learn more about neurological diagnostic tests and procedures.

Treating dementia

Although there are no cures for the different types of dementia, there are FDA-approved treatments that can slow Alzheimer’s disease, which usually gets worse over time.

Several treatments can help a person manage their symptoms. Medicines can help treat other diseases that happen at the same time as dementia, like diabetes and depression. A team of doctors, nurses, and speech, physical, and other therapists that know a lot about dementia can help people find help to manage the symptoms of dementia. Many potential medicines for Alzheimer’s and other types of dementia are currently being tested in clinical trials.

Therapy

Speech and physical therapists can help a person with dementia who is having problems with movement, speech, and swallowing. They can also help people learn new ways to handle everyday tasks, like eating. Physical activity can also improve mood and quality of life for people with dementia.

Medicines

AD: Medicines called cholinesterase inhibitors can help memory and thinking skills in people with AD for a time by improving communication between brain cells. These medicines include donepezil, rivastigmine, and galantamine. Other medicines, called NMDA receptor antagonists, help protect brain cells and may help keep learning and memory problems from getting worse. These medicines do not cure AD, but they can help some people function better for a period of time. Two new medicines, lecanemab (Leqembi™) and donanemab (Kisunla™), work by attaching to amyloid protein and removing it from the brain. These treatments are given to people in early stages of AD. They do not cure AD but may slow its progress.

FTD: Some medicines like sedatives or antidepressants may help manage some of the behavioral symptoms of FTD, but no medicines can prevent it from getting worse.

LBD: Some medicines can help manage LBD symptoms such as trouble moving, stiffness, and seeing or believing things that are not real (hallucinations).   

VCID: Medicines can help lower the risk of VCID by protecting blood vessels and preventing strokes and further brain damage. Some studies suggest that medicines that improve memory in AD might help people with mild vascular dementia. Treating some health risk factors, like high blood pressure, can also help prevent strokes that can damage the brain and cause VCID.

Caregivers

Helping family, friends, and caregivers understand a loved one's condition is especially important for people with dementia and can make caregiving less stressful. Support groups offered by professional organizations (see list at the end of this page) help people with dementia and their families by providing resources and a space for families and other caregivers to share experiences and express concerns.

What are the latest updates on dementia?

The National Institutes of Health (NIH), which includes NINDS, is the leading federal funder of research on the brain and nervous system, including disorders such as dementia. NIH supports new and innovative research to better understand, diagnose, and treat dementia.

Another NIH institute, the National Institute on Aging (NIA), is a leading federal funder of research on AD, whereas NINDS leads research on AD-related dementia. As part of NIH, NINDS and NIA fund more than 2,500 projects in this area.

Ongoing research may lead to new ways to understand the causes of dementia and to diagnose, treat, or prevent dementia.

NIH funds dementia research programs, including:

• The Accelerating Medicines Partnership® Program for Alzheimer's Disease (AMP® AD) brings together NIH, drug companies, and nonprofit organizations to develop new AD medicines and test existing ones.
• ALLFTD is a comprehensive study targeting most varieties of FTD, including individuals from families affected by genetic mutations (i.e., familial) and those who have no apparent family history (i.e., sporadic). The goal of ALLFTD is to enable clinical trials for FTD.
• The M2OVE—AD: Molecular Mechanisms of the Vascular Etiology of Alzheimer's Disease program helps scientists  work together to understand how problems with blood vessels affect AD and to find new ways to prevent and treat the condition. 
• The Dementia with Lewy Body Biomarkers Consortium helps researchers collect and share health information and blood or tissue samples  from people with LBD. This makes it easier for researchers to learn about what other scientists are doing and to confirm their test results.

Current NIH research on dementia includes:

• Researchers are developing new dementia biomarkers, which are biological indicators of dementia that can be directly measured. For example, new biomarkers measured in a patient’s blood can accurately indicate if someone has unhealthy levels of Alzheimer’s amyloid in their brain. Researchers are also developing new imaging biomarkers to speed up diagnosis. These biomarkers will also help get people into clinical trials at the earliest stages of disease. 
• Scientists are testing many different possible medicines that might keep dementia symptoms from getting worse. For example, NIH-supported researchers are testing potential treatments for AD, FTD, and LBD that minimize protein clumping in the brain. Other NIH studies are testing medicines used for other health conditions to see if they might also work to treat dementia.
• Researchers are studying how different types of protein clumping affect the brains of people living with dementia. Learning how to block these changes could lead to effective treatments. 
• Researchers are studying whether exercise and activities that keep the mind active may help people with AD and other types of dementia.
• NIH scientists continue to look for gene variants to better understand what causes AD, FTD, and other types of dementia. 
• Brain scans may also help researchers better understand changes in the brains of people with dementia and help diagnose these disorders early.
• The International Alzheimer's Disease Research Portfolio shows what AD research is being done worldwide and where more research is needed. 

For more information on research about dementia, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects. 

For research articles and summaries on dementia, search PubMed, which contains citations from medical journals and other sites.

How can I or my loved one help improve care for people with dementia?

Consider participating in a clinical trial so clinicians and scientists can learn more about dementia and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with dementia at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results. Alzheimers.gov also has a page specific to clinical trials for AD and related dementia.

Learn about related topics

• Alzheimer's Disease (AD)
• Frontotemporal Dementia
• Lewy Body Dementia
• Stroke