Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn.
Typically, symptoms include memory loss, problems using language and doing activities, personality changes, disorientation, and disruptive or inappropriate behavior.
Symptoms progress so that people cannot function, causing them to become totally dependent on others.
Doctors base the diagnosis on symptoms and results of a physical examination and mental status tests.
Blood and imaging tests are used to determine the cause.
Treatment focuses on maintaining mental function as long as possible and providing support as the person declines.
(See also Overview of Delirium and Dementia.)
Dementia occurs primarily in people older than 65. Dementia, particularly the disruptive behavior that often accompanies it, is the reason for more than 50% of admissions to nursing homes. However, dementia is a disorder and is not a part of normal aging. Many people over 100 do not have dementia.
Dementia differs from delirium, which is characterized by an inability to pay attention, disorientation, an inability to think clearly, and fluctuations in the level of alertness.
Dementia affects mainly memory, and delirium affects mainly attention.
Dementia typically begins gradually and has no definite beginning point. Delirium begins suddenly and often has a definite beginning point.
Age-related changes in the brain (also called age-associated memory impairment) cause some decline in short-term memory and slowing in learning ability. Memories are retrieved more slowly. These changes, unlike dementia, occur normally as people age and do not affect the ability to function and do daily tasks. Such memory loss in older people is not necessarily a sign of dementia or early Alzheimer disease. However, the earliest symptoms of dementia are very similar.
Mild cognitive impairment causes greater memory loss than age-associated memory impairment. It may also impair the ability to use language, think, and use good judgment. However, it, like age-associated memory impairment, does not affect the ability to function or do daily tasks. Up to half of people with mild cognitive impairment develop dementia within 3 years.
Subjective cognitive decline refers to a continuing decline in mental function that the affected person notices but that is not identified by standardized tests for mild cognitive impairment. People with subjective cognitive decline perform normally on such tests. However, these people are more likely to develop mild cognitive impairment and dementia.
Dementia is a much more serious decline in mental ability and one that worsens with time. People who are aging normally may misplace things or forget details, but people who have dementia may forget entire events. People who have dementia have difficulty doing normal daily tasks such as driving, cooking, and handling finances.
Rapidly progressive dementia is a group of dementias that progress faster than other dementias. typically within 1 to 2 years. The most obvious early symptom of these dementias is rapidly decreasing mental function. Memory is lost. People have difficulty using language. They also have difficulty planning, solving problems, handling complex tasks (such as managing a bank account), and using good judgment (called executive function).
Other symptoms of rapidly progressive dementias include disruptive behavior, personality changes, mood disorders, psychosis, problems sleeping, and problems walking. Levels of alertness and awareness may be altered. Their limbs may shake and/or jerk involuntarily. The most common cause of rapidly progressive dementia is a prion disorder. Other common causes include autoimmune and paraneoplastic encephalitis. Sometimes other types of dementias progress faster than is typical. They include some cases of Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia, and dementia due to potentially reversible causes.
Depression may resemble dementia, especially in older people, but the two can often be distinguished. For example, people with depression may eat and sleep little. However, people with dementia usually eat and sleep normally until later in the disease. People with depression may complain bitterly about their memory loss but rarely forget important current events or personal matters. In contrast, people with dementia lack insight about their mental impairments and often deny memory loss. Also, people with depression regain mental function after the depression is treated. However, many people have depression and dementia. In these people, treatment of depression may improve but not entirely restore mental function.
In some types of dementia (such as Alzheimer disease), the level of acetylcholine in the brain is low. Acetylcholine is a chemical messenger (called a neurotransmitter) that helps nerve cells communicate with one another. Acetylcholine helps with memory, learning, and concentration and helps control the functioning of many organs. Other changes occur in the brain, but whether they cause or result from dementia is unclear.
Did You Know...
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Causes of Dementia
Dementia usually occurs as a brain disorder with no other cause (called a primary brain disorder), but it can be caused by many disorders.
Common causes of dementia
Most commonly, dementia is
Alzheimer disease, a primary brain disorder
About 60 to 80% of older people with dementia have Alzheimer disease.
Other common types of dementia include
Vascular dementia (also called vascular cognitive impairment and dementia)
Frontotemporal dementia (such as Pick disease)
People may have more than one of these dementias (a disorder called mixed dementia). The most common mixed dementia is Alzheimer disease plus vascular cognitive impairment and dementia
Other disorders that can cause dementia
Disorders that can cause dementia include the following:
Parkinson disease (a common cause, but the dementia occurs late in the disease)
Brain damage due to a head injury or certain tumors
Prion diseases, such as Creutzfeldt-Jakob disease (which causes a rapidly progressive dementia)
Syphilis that affects the brain (neurosyphilis)
Reversible or treatable causes of dementias
Most of the conditions that cause dementia cannot be reversed, but some can be treated and may be called reversible dementia. (Some experts use the term dementia only for conditions that progress and cannot be reversed and use terms such as encephalopathy or cognitive loss when dementia may be partly reversible.) Treatment can often cure these dementias if the brain has not been damaged too much. If brain damage is more extensive, treatment often does not reverse the damage, but it can prevent new damage.
Conditions that cause reversible dementia include the following:
Deficiency of thiamin, , or vitamin B12
An underactive thyroid gland (hypothyroidism)
Brain tumors that can be removed
Toxins (such as lead, mercury, or other heavy metals)
Neurosyphilis if treated early
Other infections (such as Lyme disease, viral encephalitis, and the fungal infection cryptococcosis)
A subdural hematoma (an accumulation of blood between the outer and middle layers of tissue that cover the brain) results when one or more blood vessels breaks, usually because of a head injury. Such injuries can be slight and may not be recognized. Subdural hematomas can cause a slow decline in mental function that may be reversed with treatment.
Other disorders
Many disorders can worsen the symptoms of dementia. They include autoimmune disorders, diabetes, chronic bronchitis, emphysema, infections, a chronic kidney disorder, liver disorders, and heart failure.
Medications
Many medications may temporarily cause or worsen symptoms of dementia. Some of these medications can be purchased without a prescription (over the counter). Sleep aids (which are sedatives), cold remedies, antianxiety medications, and some antidepressants are common examples.
Drinking alcohol, even in moderate amounts, may also worsen dementia, and most experts recommend that people with dementia stop drinking alcohol. Recreational drugs can also make dementia worse.
Symptoms of Dementia
Progression of dementia symptoms
In people with dementia, mental function typically deteriorates over a period of 2 to 10 years. However, dementia progresses at different rates depending on the cause:
In people with vascular dementia (which is usually caused by strokes), symptoms tend to worsen in steps, worsening suddenly with each new stroke, with some improvement in between.
In people with Alzheimer disease or dementia with Lewy bodies, symptoms tend to worsen more steadily.
In Creutzfeldt-Jakob disease, dementia progresses rapidly and continuously.
The rate of progression also varies from person to person. Looking back at how fast it worsened during the previous year often gives an indication about the coming year. Symptoms may worsen when people with dementia are moved to a nursing home or another institution because people with dementia have difficulty learning and remembering new rules and routines.
Problems, such as pain, shortness of breath, retention of urine, and constipation, may cause delirium with rapidly worsening confusion in people who have dementia. If these problems are corrected, people usually return to the level of functioning they had before the problem.
General dementia symptoms
Symptoms of most dementias are similar. Generally, dementia causes the following:
Problems using language
Changes in personality
Disorientation
Problems doing usual daily tasks
Disruptive or inappropriate behavior
Although when symptoms occur varies, categorizing them as early, intermediate, or late symptoms helps affected people, family members, and other caregivers have some idea of what to expect.
Personality changes and disruptive behavior (behavior disorders) may develop early or late. Some people with dementia have seizures, which can also occur at any point in the disease.
Early dementia symptoms
Early symptoms of dementia tend to be mild.
Because dementia usually begins slowly and worsens over time, it may not be identified at first.
One of the first mental functions to noticeably deteriorate is
Memory, especially for recent events
Also, people with dementia typically have more and more difficulty doing the following:
Finding and using the right word
Understanding language
Thinking abstractly, as when working with numbers
Doing many daily tasks, such as finding their way around and remembering where they put things
Using good judgment
Emotions may be changeable, unpredictably and rapidly switching from happiness to sadness.
Changes in personality are also common. Family members may notice unusual behavior.
Some people with dementia hide their deficiencies well. They follow established routines at home and avoid complex activities such as balancing a checkbook, reading, and working. People who do not modify their lives may become frustrated with their inability to do daily tasks. They may forget to do important tasks or may do them incorrectly. For example, they may forget to pay bills or turn off the lights or stove.
Early in dementia, people may be able to continue driving, but they may become confused in congested traffic and get lost more easily.
Intermediate dementia symptoms
As dementia worsens, the existing problems worsen and expand, causing the following to become difficult or impossible:
Learning and remembering new information
Sometimes remembering events from the past
Doing daily self-care tasks, such as bathing, eating, dressing, and going to the toilet
Recognizing people and objects
Keeping track of time and knowing where they are
Understanding what they see and hear (leading to confusion)
Controlling their behavior
People often get lost. They may be unable to find their own bedroom or bathroom. They can walk but are more likely to fall.
In about 10% of people, this confusion leads to symptoms of a psychosis, such as hallucinations, delusions (false beliefs usually involving a misinterpretation of perceptions or experiences), or paranoia (unwarranted feelings of being persecuted).
As dementia progresses, driving becomes more and more difficult because it requires making quick decisions and coordinating many manual skills. People may not remember where they are going.
Personality traits may become more exaggerated. People who were always concerned with money become obsessed with it. People who were often worried become constant worriers. Some people become irritable, anxious, self-centered, inflexible, or more easily angered. Others become more passive, expressionless, depressed, indecisive, or withdrawn. If changes in their personality or mental function are mentioned, people with dementia may become hostile or agitated.
Sleep patterns are often abnormal. Most people with dementia sleep an appropriate amount, but they spend less time in deep sleep. As a result, they may become restless at night. They may also have problems falling or staying asleep. If people do not exercise enough or do not participate in many activities, they may sleep too much during the day. Then they do not sleep well at night.
Behavior disorders in dementia
Because people are less capable of controlling their behavior, they sometimes act inappropriately or disruptively (for example, by yelling, throwing, hitting, or wandering). These actions are called behavior disorders.
Several effects of dementia contribute to these actions:
Because people with dementia have forgotten the rules of proper behavior, they may act in socially inappropriate ways. When hot, they may undress in public. When they have sexual impulses, they may masturbate in public, use off-color or lewd language, or make sexual demands.
Because they have difficulty understanding what they see and hear, they may misinterpret an offer of help as a threat and may lash out. For example, when someone tries to help them undress, they may interpret it as an attack and try to protect themselves, sometimes by hitting.
Because their short-term memory is impaired, they cannot remember what they are told or have done. They repeat questions and conversations, demand constant attention, or ask for things (such as meals) they have already received. They may become agitated and upset when they do not get what they ask for.
Because they cannot express their needs clearly or at all, they may yell when in pain or wander when lonely or frightened. They may wander, yell, or call out when they cannot sleep.
Whether a particular behavior is considered disruptive depends on many factors, including how tolerant the caregiver is and what sort of situation the person with dementia is living in. If the person lives in a safe environment (with locks and alarms on all doors and gates), wandering may be tolerable. However, if the person lives in a nursing home or hospital, wandering may be intolerable because it disturbs other residents or interferes with the operation of the institution. Caregivers may tolerate disruptive behavior better during the day than in the evening.
Late (severe) dementia symptoms
Eventually, people with dementia become unable to follow conversations and become unable to speak. Memory for recent and past events is completely lost. People may not recognize close family members or even their own face in a mirror.
When dementia is advanced, the brain’s ability to function is almost completely destroyed. Advanced dementia interferes with control of muscles. People cannot walk, feed themselves, or do any other daily tasks. They become totally dependent on others and eventually are unable to get out of bed.
Eventually, people may have difficulty swallowing food without choking. These problems increase the risk of undernutrition, pneumonia (often due to inhaling secretions or particles from the mouth), and pressure sores (because they cannot move).
Death often results from an infection, such as pneumonia.
Diagnosis of Dementia
A doctor's evaluation
Mental status testing
Sometimes neuropsychologic testing
Blood tests and imaging tests to rule out causes
Forgetfulness is usually the first sign of dementia noticed by family members or doctors.
Medical history
Doctors and other health care practitioners can usually diagnose dementia by asking the person and family members a series of questions, such as the following:
What is the person’s age?
Has any family member had dementia or other types of mental dysfunction (family history)?
When and how did symptoms start?
How quickly did symptoms worsen?
How has the person changed (for example, has the person given up hobbies and activities)?
What other disorders does the person have?
What drugs is the person taking (because certain drugs can cause symptoms of dementia)?
Has the person been depressed or sad, especially if the person is older?
Mental function testing
The person is also given a mental status test, consisting of simple questions and tasks, such as naming objects, recalling short lists, writing sentences, and copying shapes. To test for memory, doctors may read a list of three objects, wait 5 minutes, then ask the person to list them. Usually, people with dementia cannot remember them.
Neuropsychologic testing, which is more detailed, is sometimes needed to clarify the degree of impairment or to determine whether the person is experiencing true mental decline. This testing covers all the main areas of mental function, including mood, and usually takes 1 to 3 hours. This testing helps doctors distinguish dementia from age-associated memory impairment, mild cognitive impairment, and depression.
With information about the person’s symptoms and family history and the results of mental status testing, doctors can usually diagnose dementia.
Based on this information, doctors can also usually rule out delirium as the cause of symptoms (see table Comparing Delirium and Dementia). Doing so is essential because delirium, unlike dementia, can often be reversed if promptly treated.
Findings that indicate dementia include the following:
People have problems with thinking and behavior that interfere with doing daily tasks.
These problems have become progressively worse, making doing daily tasks more and more difficult.
People do not have delirium or a psychiatric disorder that could be causing the problems.
In addition, people have at least two of the following:
Difficulty learning and remembering new information
Difficulty using language
Difficulty understanding where objects are in space, recognizing objects and faces, and understanding how parts of a whole relate to each other
Difficulty planning, solving problems, handling complex tasks (such as managing a bank account), and using good judgment (executive function)
Changes in personality, behavior, or demeanor
Physical examination
A physical examination, including a neurologic examination, is usually done to determine whether other disorders are present. Doctors look for treatable disorders that may be causing, contributing to, or mistaken for dementia.
Doctors also determine whether another, unrelated physical disorder or psychiatric disorder (such as schizophrenia) is also present because treatment of these disorders may improve the general condition of people with dementia.
Other testing
Blood tests are done. They typically include measuring blood levels of thyroid hormones to check for thyroid disorders and levels of vitamin B12 to check for a deficiency.
If doctors suspect that the cause of dementia is an infection that affects the brain (such as neurosyphilis), an autoimmune disorder, or prion disease, a spinal tap (lumbar puncture) is done.
Computed tomography (CT) or magnetic resonance imaging (MRI) is done during the initial evaluation of dementia. These imaging tests can identify abnormalities that can cause dementia (such as a brain tumor, normal-pressure hydrocephalus, a subdural hematoma, and stroke).
Positron emission tomography (PET) or single-photon emission CT (SPECT) is sometimes done to help doctors identify different types of dementia, such as Alzheimer disease, frontotemporal dementia, and dementia with Lewy bodies. These imaging tests use radioactive substances to produce images.
However, sometimes the cause of the dementia can be confirmed definitively only when a sample of brain tissue is removed and examined under a microscope. This procedure is sometimes done after death during an autopsy.
Treatment of Dementia
Management of conditions that may be causing dementia or making it worse
Safety and supportive measures
Medications that may improve mental function
Caregiver care
End-of-life decisions
For most dementias, no treatment can restore mental function. However, treating disorders that are causing or worsening dementia can sometimes stop or reverse the dementia. Such disorders include an underactive thyroid, a subdural hematoma, normal-pressure hydrocephalus, and vitamin B12 deficiency. When such disorders develop in people who already have dementia, treating them sometimes slows mental decline. For people who have dementia and depression, antidepressants
Pain and any other disorders or health problems (such as a urinary tract infection or constipation), whether they are related to the dementia or not, are treated. Such treatment may help maintain function in people with dementia.
Creating a safe and supportive environment can be remarkably helpful, and certain medications can help for a while. The person with dementia, family members, other caregivers, and the health care practitioners involved should discuss and decide on the best strategy for that person.
Safety measures
Safety is a concern. A visiting nurse or an occupational or a physical therapist can evaluate homes for safety and recommend useful changes. For example, when the light is dim, people with dementia are even more likely to misinterpret what they see, so lighting should be relatively bright. Leaving a night-light on or installing motion sensor lights may also help. Such changes can help prevent accidents (particularly falls) and help people function better.
Doctors may evaluate how well people with dementia function in specific situations, such as while preparing food or driving. If skills are impaired, safety measures, such as hiding knives or taking the car keys away, may be needed.
Supportive measures
People who have mild to intermediate dementia usually function best in familiar surroundings and can usually remain at home.
Generally, the environment should be bright, cheerful, safe, and stable and include some stimulation, such as a radio or television. The environment should be designed to help with orientation. For example, windows enable people to know generally what time of day it is.
Structure and routine help people with dementia stay oriented and give them a sense of security and stability. Any change in surroundings, routines, or caregivers should be explained to people clearly and simply. Before every procedure or interaction, they should be told what is going to happen, such as a bath or a meal. Taking time to explain can help prevent a fight.
Following a daily routine for tasks such as bathing, eating, and sleeping helps people with dementia remember. Following a regular routine at bedtime may help them sleep better.
Other activities scheduled on a regular basis can help people feel independent and needed by focusing their attention on pleasurable or useful tasks. Such activities can also help relieve depression. Activities related to interests people had before dementia are good choices. Activities should also be enjoyable and provide some stimulation but not too many choices or challenges.
Physical activity relieves stress and frustration and thus can help prevent sleep problems and disruptive behavior, such as agitation and wandering. It also helps improve balance (and thus may help prevent falls) and helps keep the heart and lungs healthy.
Continued mental activity, including hobbies, interest in current events, and reading, helps keep people alert and interested in life. Activities should be broken down in small parts or simplified as the dementia worsens.
Excessive stimulation should be avoided, but people should not be socially isolated.
Frequent visits by staff members and familiar people encourage people to remain social.
Some improvement may occur if
Daily routines are simplified.
Expectations for people with dementia are realistic.
They are enabled to maintain some sense of dignity and self-esteem.
Extra help may be needed. Family members can get a list of available services from health care practitioners, social or human services, or the Internet (through Eldercare Locator). Services may include housekeeping, respite care, meals brought to the home, and daycare programs and activities designed for people with dementia. Around-the-clock care can be arranged but is expensive. The Alzheimer’s Association offers a Safe Return program. This program alerts a community support network that can help return people to their caregiver or a family member.
Planning for the future is essential because dementia is usually progressive. Long before a person with dementia needs to be moved to a more supportive and structured environment, family members should plan for this move and evaluate the options for long-term care. Such planning usually involves the efforts of a doctor, a social worker, nurses, and a lawyer, but most of the responsibility falls on family members. Decisions about moving a person with dementia to a more supportive environment involve balancing the desire to keep the person safe with the desire to maintain the person’s sense of independence as long as possible. Such decisions depend on many factors, such as the following:
Severity of the dementia
How disruptive the person’s behavior is
Home environment
Availability of family members and caregivers
Financial resources
Presence of other, unrelated disorders and physical problems
Some long-term care facilities, including assisted living facilities and nursing homes, specialize in caring for people with dementia. Staff members are trained to understand how people with dementia think and act and how to respond to them. These facilities have routines that make the residents feel secure and provide appropriate activities that help them feel productive and involved in life. Most facilities have appropriate safety features. For example, signs are posted to help residents find their way, and certain doors have locks or alarms to prevent residents from wandering. If one facility does not have these and other safety features, transferring a person who develops a behavior problem to a facility that has these features is usually a better solution than using medications to control the behavior.
Some people with dementia worsen when they are moved from their home to a long-term care facility. However, after a short time, most people adjust and function better in the more supportive environment.
Medications that may improve mental function
Alzheimer disease and dementia with Lewy bodiesdementia related to Parkinson disease.
If one cholinesterase inhibitor is ineffective or has side effects, another should be tried. If none is effective or all have side effects, this type of medication should be stopped. The most common side effects include nausea, vomiting, weight loss, and abdominal pain or cramps. Tacrine, the first cholinesterase inhibitor developed for treating dementia, is rarely used anymore because it can damage the liver.
N-methyl-d
Medications that help control disruptive behavior
If disruptive behavior develops, medications are sometimes used. However, disruptive behavior is best controlled with strategies that do not include medications and are tailored to the specific person. Medications are used only when other strategies, such as changes in the environment, are ineffective and when using medications is essential to keeping the person with dementia and/or others safe.
These medications include the following:
Antipsychotic medications: These medications are often used to control the agitation and outbursts that may accompany advanced dementia. However, antipsychotic medications tend to be effective only in people who have hallucinations, delusionshyperlipidemia) and increase the risk of type 2 diabetes. In older people with psychotic behavior and dementia, newer antipsychotic medications may increase the risk of stroke and death. Antipsychotic medications should be used only when dementia is accompanied by psychotic behavior.
Other medications
Sedatives
Antidepressants, usually selective serotonin reuptake inhibitors, are used only when people with dementia also have depression.
If medications are used, family members should talk with the doctor periodically about whether the medications are really helping.
Dietary supplements
, a dietary supplement, is marketed as a memory enhancer. However, studies do not show any benefit from taking , and in high doses, it may have side effects.
Vitamin B12 supplements are effective only in people who have vitamin B12 deficiency
Before using any dietary supplement, people should talk with their doctor.
Care for caregivers
Caring for people with dementia is stressful and demanding, and caregivers may become depressed and exhausted, often neglecting their own mental and physical health.
The following measures can help caregivers:
Learning about how to effectively meet the needs of people with dementia and what to expect from them: Caregivers can get this information from nurses, social workers, organizations, and published and online materials.
Seeking help when it is needed: Caregivers can talk to social workers (including those in the local community hospital) about appropriate sources of help, such as day-care programs, visits by home nurses, part-time or full-time housekeeping assistance, and live-in assistance. Counseling and support groups can also help.
Caring for self: Caregivers need to remember to take care of themselves. They should not give up their friends, hobbies, and activities.
Caring for Caregivers
Caring for people with dementia is stressful and demanding, and caregivers may become depressed and exhausted, often neglecting their own mental and physical health. The following measures can help caregivers:
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End-of-life issues
Before people with dementia become too incapacitated, decisions should be made about medical care, and financial and legal arrangements should be made. These arrangements are called advance directives. People should appoint a person who is legally authorized to make treatment decisions on their behalf (health care proxy) and discuss health care wishes with this person and their doctor (see Legal and Ethical Concerns). For example, people with early-stage dementia should decide whether they want artificial feeding or antibiotics to treat infections (such as pneumonia) when dementia is very advanced. Such issues are best discussed with all concerned long before decisions are necessary.
As dementia worsens, treatment tends to be directed at maintaining the person’s comfort rather than at attempting to prolong life. Often, aggressive treatments, such as artificial feeding, increase discomfort.
In contrast, less drastic treatments can relieve discomfort. These treatments include
Adequate control of pain
Skin care (to prevent pressure sores)
Attentive nursing care
Nursing care is most helpful when it is provided by one caregiver (or a few) who develops a consistent relationship with the person. A comforting, reassuring voice and soothing music may also help.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Alzheimer's Association: Information about Alzheimer disease, including statistics, causes, risk factors, and symptoms. Also resources for support, including information about daily care of people with Alzheimer disease, care for the caregiver, and support groups.
The Alzheimer's Society: A guide to dementia (including five things important things to know), a guide for caregivers, and information about the types of dementia, symptoms, diagnosis, treatments, risk factors, and prevention.
Dementia.org: Information about the causes, symptoms, treatments, and stages of dementia.
Health Direct: Dementia Video Series: General information about dementia, recommendations about the warning signs of dementia, treatment and research, and caring for a person with dementia. Also provides links to articles on similar topics.
National Institute of Neurological Disorders and Stroke's Dementia Information Page: Information about treatments and prognosis and links to clinical trials.
