Dementia
Lewy body dementia; DLB; Vascular dementia; Mild cognitive impairment; MCI; Alzheimer disease - dementiaDementia is a loss of brain function that occurs with certain diseases. It affects one or more brain functions such as memory, thinking, language, judgment, or behavior. Dementia may also be referred to as major neurocognitive disorder.
Neurocognitive disorder
Neurocognitive disorder is a general term that describes decreased mental function due to a medical disease other than a psychiatric illness. Neuroco...

Causes
Dementia usually occurs in older age. Most types are rare in people under age 60. The risk of dementia increases as a person gets older.
Most types of dementia are nonreversible (degenerative). Nonreversible means the changes in the brain that are causing the dementia cannot be stopped or turned back. Alzheimer disease is the most common type of dementia.
Alzheimer disease
Dementia is a loss of brain function that occurs with certain diseases. Alzheimer disease (AD) is the most common form of dementia. It affects memo...

Another common type of dementia is vascular dementia. It is caused by poor blood flow to the brain, such as with stroke.
Vascular dementia
Dementia is a permanent loss of specific brain functions. This occurs with certain diseases. It affects memory, thinking, language, judgment, and b...

Lewy body disease is another cause of dementia in older adults. People with this condition have abnormal protein structures in certain areas of the brain. Any condition that results in injury to the brain can cause dementia.
The following medical conditions can also lead to dementia:
- Huntington disease
Huntington disease
Huntington disease (HD) is a genetic disorder in which nerve cells in certain parts of the brain waste away, or degenerate. The disease is passed do...
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- Multiple sclerosis
Multiple sclerosis
Multiple sclerosis (MS) is an autoimmune disease that affects the brain and spinal cord (central nervous system).
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AIDS
Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...
ImageRead Article Now Book Mark ArticleSyphilis
Neurosyphilis is a bacterial infection of the brain or spinal cord. It usually occurs in people who have had untreated syphilis for many years....
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Lyme disease is a bacterial infection that is spread through the bite of one of several types of ticks.
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Parkinson disease
Parkinson disease results from certain brain cells dying. These cells help control movement and coordination. The disease leads to shaking (tremors...
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Pick disease
Frontotemporal dementia (FTD) is a rare form of dementia that is similar to Alzheimer disease, except that it tends to affect only certain areas of t...
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Progressive supranuclear palsy
Progressive supranuclear palsy (PSP) is a movement disorder that occurs from damage to certain nerve cells in the brain.
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Some causes of dementia may be stopped or reversed if they are found soon enough, including:
- Brain injury
- Brain tumors
- Long-term (chronic) alcohol abuse
- Changes in blood sugar, sodium, and calcium levels (dementia due to metabolic causes)
Dementia due to metabolic causes
Dementia is loss of brain function that occurs with certain diseases. Dementia may also be referred to as major neurocognitive disorder. Dementia du...
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Vitamin B12
Vitamin B12 is a water-soluble vitamin. Water-soluble vitamins dissolve in water. After the body uses these vitamins, leftover amounts leave the bo...
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Normal pressure hydrocephalus
Hydrocephalus is a buildup of spinal fluid inside the fluid chambers of the brain. Hydrocephalus means "water on the brain. "Normal pressure hydroce...
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- Some brain infections
Symptoms
Dementia symptoms include difficulty with many areas of mental function, including:
- Emotional behavior or personality
- Language
- Memory
- Perception
- Thinking and judgment (cognitive skills)
Dementia usually first appears as forgetfulness.
Mild cognitive impairment (MCI) is the stage between normal forgetfulness due to aging and the development of dementia. People with MCI have mild problems with thinking and memory that do not interfere with daily activities. They often know about their forgetfulness. Not everyone with MCI develops dementia.
Symptoms of MCI include:
- Difficulty doing more than one task at a time
- Difficulty solving problems or making decisions
- Forgetting names of familiar people, recent events, or conversations
- Taking longer to do more difficult mental activities
Early symptoms of dementia can include:
- Difficulty with tasks that take some thought, but that used to come easily, such as balancing a checkbook, playing games (such as bridge), and learning new information or routines
- Getting lost on familiar routes
- Language problems, such as trouble with the names of familiar objects
- Losing interest in things previously enjoyed, flat mood
- Misplacing items
- Personality changes and loss of social skills, which can lead to inappropriate behaviors
- Mood changes leading to aggressive behavior
- Poor performance of job duties
As dementia becomes worse, symptoms are more obvious and interfere with the ability to take care of oneself. Symptoms may include:
- Change in sleep patterns, often waking up at night
- Difficulty with basic tasks, such as preparing meals, choosing proper clothing, or driving
- Forgetting details about current events
- Forgetting events in one's own life history, losing self-awareness
- Having hallucinations, arguments, striking out, and violent behavior
Hallucinations
Hallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.
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- More difficulty reading or writing
- Poor judgment and loss of ability to recognize danger
- Using the wrong word, not pronouncing words correctly, speaking in confusing sentences
- Withdrawing from social contact
People with severe dementia can no longer:
- Perform basic activities of daily living, such as eating, dressing, and bathing
- Recognize family members
- Understand language
Other symptoms that may occur with dementia:
- Problems controlling bowel movements or urine
- Swallowing problems
Exams and Tests
A skilled health care provider can often diagnose dementia using the following:
- Complete physical exam, including nervous system exam
- Asking about the person's medical history and symptoms
- Mental function tests (mental status examination)
Other tests may be ordered to find out if other problems may be causing dementia or making it worse. These conditions include:
- Anemia
Anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...
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Brain tumor
A primary brain tumor is a group (mass) of abnormal cells that start in the brain.
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- Intoxication from medicines
- Severe depression
- Thyroid disease
- Vitamin deficiency
The following tests and procedures may be done:
- B12 level
B12 level
The vitamin B12 level is a blood test that measures how much vitamin B12 is in your blood.
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Ammonia
Ammonia is a strong, colorless gas. If the gas is dissolved in water, it is called liquid ammonia. Poisoning may occur if you breathe in ammonia. ...
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Chem-20
A comprehensive metabolic panel is a group of blood tests. They provide an overall picture of your body's chemical balance and metabolism. Metaboli...
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Blood gas analysis
Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine the acidity (pH) of your blood.
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Cerebrospinal fluid (CSF) analysis
A CSF cell count is a test to measure the number of red and white blood cells that are in cerebrospinal fluid (CSF). CSF is a clear fluid that is in...
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Toxicology screen
A toxicology screen refers to various tests that determine the type and approximate amount of legal and illegal drugs a person has taken by measuring...
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Electroencephalograph
An electroencephalogram (EEG) is a test to measure the electrical activity of the brain.
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Head CT
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.
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- Neuropsychological test
- MRI of head
MRI of head
A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...
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Thyroid function tests
Thyroid function tests are used to check whether your thyroid is working normally. The most common thyroid function tests are:Free T4 (the main thyro...
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Thyroid stimulating hormone
A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland. It prompts the thyroid g...
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Urinalysis
Urinalysis is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds th...
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Treatment
Treatment depends on the condition causing the dementia. Some people may need to stay in the hospital for a short time.
Sometimes, dementia medicine can make a person's confusion worse. Stopping or changing these medicines is part of the treatment.
Certain mental exercises can help with dementia.
Treating conditions that can lead to confusion often greatly improve mental function. Such conditions include:
- Anemia
- Decreased blood oxygen (hypoxia)
Hypoxia
A bluish color to the skin or mucous membrane is usually due to a lack of oxygen in the blood. The medical term is cyanosis.
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- Heart failure
Heart failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
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- Nutritional disorders
- Thyroid disorders
Medicines may be used to:
- Slow the rate at which symptoms get worse, though improvement with these drugs may be small
- Control problems with behavior, such as loss of judgment or confusion
Someone with dementia will need support in the home as the disease gets worse. Family members or other caregivers can assist by helping the person cope with memory loss and behavior and sleep problems. It is important to make sure the homes of people who have dementia are safe for them.
Support in the home
Dementia is a loss of cognitive function that occurs with certain diseases. It affects memory, thinking, and behavior.
Read Article Now Book Mark ArticleMemory loss
People who have dementia may have trouble with: Language and communicationEatingHandling their own personal care

Behavior and sleep problems
People with dementia often have certain problems when it gets dark at the end of the day and into the night. This problem is called sundowning. The...

Safe for them
It is important to make sure the homes of people who have dementia are safe for them.

Outlook (Prognosis)
People with MCI do not always develop dementia. When dementia does occur, it usually gets worse over time. Dementia often decreases quality of life and lifespan. Families will likely need to plan for their loved one's future care. The prognosis depends on the underlying cause. Some dementias rapidly progress to death while others can take years to get worse.
Future care
Dementia is a loss of cognitive function that occurs with certain diseases. It affects memory, thinking, and behavior.
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Contact your provider if:
- Dementia develops or a sudden change in mental status occurs
Change in mental status
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
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- You are unable to care for a person with dementia at home
Prevention
Most causes of dementia are not preventable.
The risk of vascular dementia may be reduced by preventing strokes through:
- Eating healthy foods
- Exercising
- Quitting smoking
- Controlling high blood pressure
- Managing diabetes
References
Knopman DS. Cognitive impairment and other dementias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 374.
Peterson R, Graff-Radford J. Alzheimer disease and other dementias. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 95.
Petersen RC, Lopez O, Armstrong MJ, et al. Practice guideline update summary: mild cognitive impairment: report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology. 2018;90(3):126-135. PMID: 29282327 pubmed.ncbi.nlm.nih.gov/29282327/.
Alzheimer disease
Animation
Brain - illustration
The major areas of the brain have one or more specific functions.
Brain
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Arteries of the brain - illustration
The internal carotid arteries and the vertebral arteries supply blood to the brain.
Arteries of the brain
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Review Date: 1/23/2022
Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.