Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn.
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.
As people age, changes in the brain cause some decline in short-term memory and slowing in learning ability. These normal age-related changes, unlike dementia, do not affect the ability to function and do daily tasks. Such memory loss in older people—sometimes called age-associated memory impairment—is not necessarily a sign of dementia or early Alzheimer disease.
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.
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.
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.
Commonly, dementia occurs as a brain disorder with no other cause (called a primary brain disorder), but it can be caused by many disorders. 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, Lewy body dementia, and frontotemporal dementia (such as Pick disease). People may have more than one of these dementias (a disorder called mixed dementia).
Disorders that can cause dementia include the following:
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:
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.
Many disorders can worsen the symptoms of dementia. They include diabetes, chronic bronchitis, emphysema, infections, a chronic kidney disorder, liver disorders, and heart failure.
Many drugs may temporarily cause or worsen symptoms of dementia. Some of these drugs can be purchased without a prescription (over the counter). Sleep aids (which are sedatives), cold remedies, antianxiety drugs, 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.
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 Lewy body dementia, 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.
Symptoms of most dementias are similar. Generally, dementia causes the following:
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 may develop early or late. Some people with dementia have seizures, which can also occur at any point in the disease.
Because dementia usually begins slowly and worsens over time, it may not be identified at first. Memory, especially for recent events, is one of the first mental functions to noticeably deteriorate. Also, people with dementia typically have more and more difficulty doing the following:
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.
As dementia worsens, the existing problems worsen and expand, causing the following to become difficult or impossible:
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 a psychosis, such as hallucinations, delusions, or paranoia.
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.
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:
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.
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. When people with dementia cannot sleep, they may wander, yell, or call out.
Eventually, people with dementia become unable to follow conversations and may 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 task. 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.
Forgetfulness is usually the first sign noticed by family members or doctors. 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:
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 (see see Table 1: Mental Status Testing). More detailed testing (called neuropsychologic testing) 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. They can also usually rule out delirium as the cause of symptoms. Doing so is essential because delirium can be reversed if promptly treated.
Findings that indicate dementia include the following:
In addition, people have at least two of the following:
A physical examination, including a neurologic examination (see see Physical 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.
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. Computed tomography (CT) or magnetic resonance imaging (MRI) is done to identify abnormalities that can cause dementia (such as a brain tumor, normal-pressure hydrocephalus, a subdural hematoma, and stroke). A special type of MRI (called functional MRI) or CT (called single-photon emission CT) is sometimes done to help doctors identify different types of dementia, such as Alzheimer disease, frontotemporal dementia, and Lewy body dementia. 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.
For most dementias, no treatment can restore mental function. However, treating disorders that are worsening the dementia sometimes slows mental decline. For people who have dementia and depression, antidepressants (such as sertraline and paroxetine—see see Table: Drugs Used to Treat Depression) and counseling may help, at least temporarily. For alcoholics who have dementia, abstaining from alcohol can result in long-term improvement. Drugs that may be making the dementia worse, such as sedatives and drugs that affect brain function, are stopped if possible. 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 drugs 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 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.
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, if expectations for people with dementia are realistic, and if 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 (listed in the telephone book), 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.
Because dementia is usually progressive, planning for the future is essential. 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:
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 drugs 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.
Drugs that may improve mental function:
Donepezil, galantamine, rivastigmine, and memantine are used to treat Alzheimer disease. Rivastigmine can also be used to treat dementia related to Parkinson disease.
Donepezil, galantamine, and rivastigmine are cholinesterase inhibitors. They inhibit acetylcholinesterase, an enzyme that breaks acetylcholine down. Thus, these drugs help increase the level of acetylcholine, which helps nerve cells communicate. These drugs may temporarily improve mental function in people with dementia, but they do not slow the progression of dementia. They are most useful in early dementia, but their effectiveness varies considerably from person to person. About one third of people do not benefit. About one third improve slightly for a few months. The rest improve considerably for a longer time, but the dementia eventually progresses. 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 drug 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.
Memantine, an NMDA (N-methyl-d-aspartate) antagonist, may improve mental function in people with moderate to severe dementia. Memantine works differently from cholinesterase inhibitors and may be used with them. The combination may be more effective than either drug alone.
Drugs that help control disruptive behavior:
If disruptive behavior develops, drugs are sometimes used. However, disruptive behavior is best controlled with strategies that do not include drugs and are tailored to the specific person. Drugs are used only when other strategies, such as changes in the environment, are ineffective and when using drugs is essential to keeping the person with dementia and/or others safe.
These drugs include the following:
Sedatives (including benzodiazepines such as lorazepam) are sometimes used for a short time to relieve anxiety related to a particular event, but such treatment is not recommended for the long term. Antidepressants are used only when people with dementia also have depression.
If drugs are used, family members should talk with the doctor periodically about whether the drugs are really helping.
Many dietary supplements have been tried but have generally proved of little value in treating dementia. They include lecithin, ergoloid mesylates, and cyclandelate. An extract of Ginkgo biloba, a dietary supplement, is marketed as a memory enhancer (see see Ginkgo). However, studies do not show any benefit from taking ginkgo, and in high doses, it may have side effects.
Vitamin B12 supplements are effective only in people who have vitamin B deficiency, and thyroid hormone replacement is effective only in those who have an underactive thyroid gland.
Before using any dietary supplement, people should talk with their doctor.
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 see Legal and Ethical Concerns at the End of Life and see see Advance Directives). For example, people with 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), and 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.
Last full review/revision July 2013 by Juebin Huang, MD, PhD