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. It is very common. In the United States, at least 5 million people have dementia. It is the reason for more than 50% of admissions to nursing homes.
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. Such memory loss in older people is sometimes called age-associated memory impairment. 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. Age-associated memory impairment is not necessarily a sign of dementia or early Alzheimer's disease.
Depression may resemble dementia, especially in older people. People with depression eat and sleep little. They 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. 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's 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's disease, a primary brain disorder. It accounts for 50 to 70% of cases. Other common types include vascular dementia, Lewy body dementia, and frontotemporal dementia (such as Pick's 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. 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, symptoms tend to worsen in steps, worsening suddenly with each new stroke, with some improvement in between. In people with Alzheimer's disease or Lewy body dementia, symptoms tend to worsen more steadily.
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 early or late.
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. 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:
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 Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: 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.
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.
A physical examination, including a neurologic examination (see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: 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.
Blood tests are done. They 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 rule out abnormalities such as a brain tumor, normal-pressure hydrocephalus, a subdural hematoma, and stroke. However, some causes of the dementia (such as Alzheimer's disease) 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.
Doctors 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.
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 Mood Disorders: Drugs Used to Treat Depression) and counseling may help, at least temporarily. 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 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 usually 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.
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 to Slow Progression:
Donepezil, galantamine, rivastigmine, and memantine are used to treat Alzheimer's disease. Rivastigmine can also be used to treat dementia related to Parkinson's disease.
Donepezil, galantamine and rivastigmine are called 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 help slow the progression of moderate to severe Alzheimer's disease. Memantine works differently from cholinesterase inhibitors and may be used with them. The combination may be more effective than a cholinesterase inhibitor alone.
Drugs to Control Behavior:
If disruptive behavior develops, drugs are sometimes used. These drugs include the following:
However, disruptive behavior is best controlled with strategies that do not include drugs and are tailored to the specific person. If drugs are used, family members should talk with the doctor about whether the drugs are really helping. Antidepressants are used only when people with dementia also have depression.
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 that is marketed as a memory enhancer, may modestly benefit some people with dementia (see Medicinal Herbs and Nutraceuticals: Ginkgo). However, evidence for ginkgo is inconsistent, and further study is needed. High doses 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 Death and Dying: Legal and Ethical Concerns at the End of Life and see Legal and Ethical Issues: 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.
Alzheimer's disease is a progressive loss of mental function, characterized by degeneration of brain tissue, including loss of nerve cells and the development of senile plaques and neurofibrillary tangles.
Most dementias are Alzheimer's disease. In older people, it accounts for 50 to 70% of dementias. It is rare among people younger than 60. It becomes more common with increasing age. It affects less than 5% of people aged 60 to 74, 19% of those aged 75 to 84, but more than 30% of those older than 85. One in eight people aged 65 and over have the disease. It affects more women than men. In 2007 in the United States, over 5 million people had Alzheimer's disease.
What causes Alzheimer's disease is unknown, but genetic factors play a role: About 5 to 15% of cases run in families. Several specific gene abnormalities may be involved. Some of these abnormalities can be inherited when only one parent has the abnormal gene. That is, the abnormal gene is dominant. An affected parent has a 50% chance of passing on the abnormal gene to each child. In some of these cases, Alzheimer's disease develops before age 60.
One gene abnormality affects apolipoprotein E (apo E)—the protein part of certain lipoproteins, which transport cholesterol through the bloodstream. There are three types of apo E (ε2, ε3, and ε4). People with the ε4 type develop Alzheimer's disease more commonly and at an earlier age than other people. In contrast, people with the ε2 type seem to be protected against Alzheimer's disease. People with the ε3 type are neither protected nor more likely to develop the disease. (These associations have been studied primarily in whites and may not apply to other races.) However, genetic testing for apo E type cannot determine whether a specific person will develop Alzheimer's disease. Therefore, this testing is not routinely recommended.
In Alzheimer's disease, parts of the brain degenerate, destroying nerve cells and reducing the responsiveness of the remaining ones to many of the chemical messengers that transmit signals between nerve cells in the brain (neurotransmitters). The level of acetylcholine, a neurotransmitter that helps with memory, learning, and concentration, is low. Abnormalities in brain tissue consist of the following:
Such abnormalities develop to some degree in all people as they age but are much more numerous in people with Alzheimer's disease.
The symptoms of Alzheimer's disease are similar to those of other dementias (see Delirium and Dementia: Symptoms). They include memory loss, changes in personality, problems using language and doing daily tasks, disorientation, and disruptive behavior. Symptoms develop gradually, so for a while, many people continue to enjoy much of what they enjoyed before developing Alzheimer's disease.
Symptoms usually begin subtly. People whose disease develops while they are still employed may not do as well in their jobs. In people who are retired and not very active, the changes may not be as noticeable.
The first sign may be forgetting recent events, although sometimes the disease begins with changes in personality. People may become emotionally unresponsive, depressed, or unusually fearful or anxious.
Early in the disease, people become less able to use good judgment and think abstractly. Speech patterns may change slightly. People may use simpler words, a general word or many words rather than a specific word, or use words incorrectly. They may be unable to find the right word.
People with Alzheimer's disease have difficulty interpreting visual and audio cues. Thus, they may become disoriented and confused. Such disorientation may make driving a car difficult. They may get lost on their way to the store. People may be able to function socially but may behave unusually. For example, they may forget the name of a recent visitor, and their emotions may change unpredictably and rapidly.
Many people with Alzheimer's disease often have insomnia. They have trouble falling or staying asleep. Some people become confused about day and night.
At some point, psychosis (hallucinations, delusions, or paranoia) develops in about half of people with Alzheimer's disease.
As Alzheimer's disease progresses, people have trouble remembering events in the past. They may require help with eating, dressing, bathing, and going to the toilet. Disruptive or inappropriate behavior, such as wandering, agitation, irritability, hostility, and physical aggression, is common. All sense of time and place is lost: People with Alzheimer's disease may even get lost on their way to the bathroom at home. Their increasing confusion puts them at risk of falling.
Eventually, people with Alzheimer's disease cannot walk or take care of their personal needs. They may be incontinent and unable to swallow, eat, or speak. These changes put them at risk of undernutrition, pneumonia, and pressure sores (bedsores). Memory is completely lost. Ultimately, coma and death, often due to infections, result.
Progression is unpredictable. People live, on average, about 7 years after the diagnosis is made. Most people with Alzheimer's disease who can no longer walk live no more than 6 months. However, how long people live varies widely.
If dementia is diagnosed in older people and their memory has gradually deteriorated, doctors consider Alzheimer's disease the most likely cause. The diagnosis is based partly on the following:
Information from the additional tests helps doctors exclude other types and causes of dementia.
The diagnosis of Alzheimer's disease is confirmed only when a sample of brain tissue is removed (after death, during an autopsy) and examined under a microscope. Then, the characteristic loss of nerve cells, neurofibrillary tangles, and senile plaques containing amyloid can be seen throughout the brain, particularly in the area of the temporal lobe that is involved in forming new memories.
Analysis of spinal fluid and positron emission tomography (PET—see Diagnosis of Heart and Blood Vessel Disorders: Positron Emission Tomography) have been suggested as ways to diagnose Alzheimer's disease during life. However, these tests are used so far only in research.
Treatment involves general measures to provide safety and support, as for all dementias (see Delirium and Dementia: Treatment).
The cholinesterase inhibitors donepezil, galantamine, and rivastigmine increase the level of the neurotransmitter acetylcholine in the brain. This level may be low. These drugs may temporarily improve cognitive function, including memory, but they do not slow the progression of the disease. About half of the people who have Alzheimer's disease benefit from these drugs. For these people, the drugs effectively turn the clock back 6 to 9 months. These drugs are most effective in people with mild to moderate disease. The most common side effects include nausea, vomiting, weight loss, and abdominal pain or cramps.
Memantine appears to slow the progression of Alzheimer's disease. Memantine can be used with a cholinesterase inhibitor.
Researchers continue to study drugs that may prevent or slow the progression of Alzheimer's disease—for example, substances that may reduce the amount of amyloid deposited. Estrogen therapy for women, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen or naproxen), and ginkgo biloba are being studied. But none has consistently proved to be effective. Moreover, estrogen appears to do more harm than good.
Vitamin E is an antioxidant that may help protect nerve cells from damage or help them function better. Vitamin E may help preserve the ability to do basic daily tasks, such as dressing and bathing, but it does not improve thinking or memory problems in people with Alzheimer's disease. When taken in reasonable amounts, vitamin E is safe and inexpensive and may slightly benefit some people. Before people take any dietary supplement, they should discuss the risks and benefits with their doctor.
Some research tentatively suggests certain measures that may help prevent Alzheimer's disease:
Vascular dementia is loss of mental function due to destruction of brain tissue because its blood supply is reduced or blocked. The cause is usually strokes, either a few large ones or many small ones.
A series of strokes may result in vascular dementia. These strokes are more common among men and usually begin after age 70. Risk factors for vascular dementia include the following:
High blood pressure, diabetes, and atherosclerosis damage blood vessels in the brain. Atrial fibrillation increases the risk of strokes due to blood clots from the heart. Unlike other types of dementia, vascular dementia can sometimes be prevented by correcting or eliminating the risk factors for strokes.
Strokes can destroy brain tissue by blocking the blood supply to parts of the brain. An area of brain tissue that is destroyed is called an infarct. Dementia may result from a few large strokes or many small ones. Some strokes cause little or no muscle weakness and seldom cause the paralysis that results from other strokes. They may seem minor or may not even be noticed. However, people may continue to have strokes, and after enough brain tissue is destroyed, dementia can develop. Thus, vascular dementia may develop before strokes cause severe or sometimes even noticeable symptoms.
Several terms have been used to describe vascular dementia. Some of them overlap:
Vascular dementia often occurs with Alzheimer's disease (as mixed dementia).
Unlike dementia caused by Alzheimer's disease, vascular dementia may progress in steps. Symptoms may worsen suddenly, then plateau or lessen somewhat. They then become worse months or years later when another stroke occurs. Dementia that results from many small strokes usually progresses more gradually than that due to a few large strokes. The small strokes may be so subtle that dementia may seem to develop gradually and continuously instead of in steps.
Symptoms (memory loss, difficulty planning and initiating actions or tasks, slowed thinking, and a tendency to wander) are similar to those of other dementias. However, compared with Alzheimer's disease, vascular dementia tends to cause memory loss later and to affect judgment and personality less. People have particular difficulty planning and initiating actions, slowed thinking may be noticeable.
Symptoms can vary depending on what part of the brain is destroyed. Usually, some aspects of mental function are not impaired because the strokes destroy tissue in only part of the brain. Thus, people may be more aware of their losses and more prone to depression than people with other types of dementia.
As more strokes occur and dementia progresses, people may have other symptoms due to the strokes. An arm or a leg may become weak or paralyzed. People may have difficulty speaking. For example, they may slur their speech. Vision may be blurred or partly or completely lost. Coordination may be lost, making walking unsteady. People may laugh or cry in appropriately. People may have difficulty controlling bladder function, resulting in urinary incontinence.
Death usually occurs about 5 years after symptoms begin. It is often due to a stroke or heart attack.
Once dementia is diagnosed, doctors suspect vascular dementia in people who have risk factors for or symptoms of a stroke. Computed tomography (CT) or magnetic resonance imaging (MRI) may be done to check for evidence of a stroke. Results of these tests can support the diagnosis but are not definitive.
Treatment involves general measures to provide safety and support, as for all dementias (see Delirium and Dementia: Treatment). Treating diabetes, high blood pressure, and high cholesterol levels can help prevent and slow or stop the progression of vascular dementia. Stopping smoking is also recommended.
There is no specific treatment for vascular dementia. Sometimes cholinesterase inhibitors and memantine, the drugs used for Alzheimer's disease, are given because some people with vascular dementia also have Alzheimer's disease. For people who have had a stroke, doctors may recommend that they take aspirin, which can reduce the risk of another stroke. People with atrial fibrillation are given warfarin, an anticoagulant, to help reduce the risk of another stroke.
Lewy Body Dementia
Lewy body dementia is progressive loss of mental function characterized by the development of Lewy bodies in nerve cells.
Lewy body dementia is a common type of dementia, but experts disagree about its prevalence and significance. It is more common among men than among women. Lewy body dementia usually develops in people older than 60.
Microscopic changes in the brain differ from those due to Alzheimer's disease. In Lewy body dementia, abnormal round deposits of protein (called Lewy bodies) form in nerve cells. Lewy bodies result in the death of nerve cells. Lewy bodies also occur in Parkinson's disease. In Parkinson's disease, they occur only in one part of the brain (deep within the brain stem), but in Lewy body dementia, they occur throughout the outer layer of the brain (cerebral cortex). Some experts think that these two disorders are variations of the same problem. People with Alzheimer's disease may develop some Lewy bodies, although neurofibrillary tangles and senile plaques seem to be the main source of damage.
The symptoms of Lewy body dementia are very similar to those of Alzheimer's disease. They include memory loss, disorientation, and problems remembering, thinking, understanding, communicating, and controlling behavior. But Lewy body dementia can be distinguished by the following:
In Lewy body dementia, hallucinations are usually visual ones, which are often complex and detailed. They may include recognizable animals or people. The hallucinations are often threatening. Over half of people with Lewy body dementia have complex, bizarre delusions. Instead of relieving these symptoms, antipsychotic drugs often make them and other symptoms worse or have other severe, sometimes life-threatening adverse effects (see Schizophrenia and Delusional Disorder: Antipsychotic Drugs).
Like people who have Parkinson's disease, people with Lewy body dementia have stiff muscles, move slowly and sluggishly, shuffle when they walk, and stoop over. Balance is easily lost, making falls more likely. Tremor also develops, but it usually develops later and causes fewer problems than it does in Parkinson's disease. Problems with thinking begin within 1 year of the time that problems with muscles and movement develop.
Sleep problems are common. Many people with Lewy body dementia have rapid eye movement (REM) sleep behavior disorder. People with this disorder act out their dreams, sometimes injuring their bed partner.
The autonomic nervous system may malfunction, preventing the body from regulating internal functions, such as blood pressure and body temperature. As a result, people may faint, sweat too much or too little, have a dry mouth, or have urinary problems or constipation.
After symptoms appear, people usually live about 6 to 12 years.
Doctors base the diagnosis on symptoms. Lewy body dementia is likely if mental function fluctuates in people who have visual hallucinations and symptoms of Parkinson's disease. Doctors must rule out delirium, which requires prompt treatment, because in delirium, mental function also fluctuates. Computed tomography (CT) and magnetic resonance imaging (MRI) may be done to rule out other causes of dementia.
Distinguishing Lewy body dementia from dementia due to Parkinson's disease can be difficult because symptoms are similar. Generally, Lewy body dementia is more likely if movement and muscle problems develop at the same time or shortly after the mental decline. Dementia due to Parkinson's disease is more likely if mental decline occurs after movement and muscle problems in people with Parkinson's disease.
Treatment involves general measures to provide safety and support, as for all dementias (see see Delirium and Dementia: Treatment). There is no specific treatment for Lewy body dementia, but the same drugs used to treat Alzheimer's disease, particularly rivastigmine, may be helpful. Drugs used to treat Parkinson's disease may help relieve the symptoms of Parkinson's disease, but they may worsen confusion, hallucinations, and delusions. Antipsychotic drugs are not used if possible.
Frontotemporal dementia, which refers to a group of dementias, results from hereditary or spontaneous (occurring for unknown reasons) disorders that cause the frontal and sometimes the temporal lobe of the brain to degenerate.
About 1 of 10 dementias is a frontotemporal dementia. Typically, the dementia develops in people younger than 65. Men and women are affected about equally. These dementias tend to run in families. Brain cells contain abnormal amounts or types of a protein called tau.
In these dementias, the frontal and temporal lobes shrink (atrophy), and nerve cells are lost. These areas of the brain are generally associated with personality and behavior. There are several types, including Pick's disease.
In this rare disorder, Pick bodies develop in nerve cells. Pick bodies contain abnormal amounts or types of tau. Pick's disease resembles Alzheimer's disease except that it affects only the frontal and temporal lobes of the brain and progresses more rapidly. Symptoms include inappropriate behavior, apathy, memory loss, carelessness, and poor personal hygiene. Death usually occurs in 2 to 10 years.
Frontotemporal dementias are progressive, but how quickly they progress to general dementia varies.
Generally, these dementias affect personality, behavior, and language function more and affect memory less than Alzheimer's disease does. People with a frontotemporal dementia also have difficulty thinking abstractly, paying attention, and recalling what they have been told. They are easily distracted. However, they usually remain aware of time, date, and place and are able to do their daily tasks.
In some people, muscles are affected. They may become weak and waste away (atrophy). Muscles of the head and neck are affected, making swallowing, chewing, and talking difficult.
Different types of symptoms develop, depending on which part of the frontal lobe is affected. People may have more than one type of symptom, particularly as the dementia progresses.
Changes in Personality and Behavior:
Some people become uninhibited, resulting in increasingly inappropriate behavior. They may speak rudely. Their interest in sex may increase abnormally.
Behavior may become impulsive and compulsive. They may repeat the same action over and over. They may walk to the same location every day. They may compulsively pick up and manipulate random objects and put objects in their mouth. They may suck or smack their lips. They may overeat or eat only one type of food.
People neglect personal hygiene.
Problems With Language:
Most people have difficulty finding words. They have increasing difficulty using and understanding language (aphasia). For some, physically producing speech (dysarthria) is difficult. Paying attention is very difficult. For some people, language problems are the only symptom for 10 or more years. For other people, other symptoms appear within a few years.
Some people cannot understand language, but they speak fluently, although what they say does not make any sense. Others have difficulty naming objects (anomia) and recognizing faces (prosopagnosia).
They speak less and less or repeat what they or others say. Eventually, they stop speaking.
The diagnosis is based on symptoms, including how they developed. Family members may have to provide this information because affected people may be unaware of their symptoms. A neurologic examination and mental status tests are usually done.
Computed tomography (CT) and magnetic resonance imaging (MRI) are done to determine which parts and how much of the brain is affected and to exclude other possible causes (such as brain tumors, abscesses, or a stroke). However, CT or MRI may not detect the characteristic changes of frontotemporal dementia until late in the disorder. Positron emission tomography (PET—see Diagnosis of Heart and Blood Vessel Disorders: Positron Emission Tomography) may help differentiate frontotemporal dementia from Alzheimer's disease, but PET is usually used only in research.
There is no specific treatment. Generally, treatment focuses on managing symptoms and providing support. For example, if compulsive behavior is a problem, antipsychotic drugs may be used. Speech therapy may help people with language problems.
Normal-pressure hydrocephalus consists of difficulty walking, urinary incontinence, and dementia due to an increase in the fluid that normally surrounds the brain.
Normally, the fluid that surrounds the brain and protects it from injury (cerebrospinal fluid) is continuously produced in the spaces within the brain (ventricles), circulates in and around the brain, and is reabsorbed. Normal-pressure hydrocephalus is thought to occur when this fluid is not reabsorbed normally, causing it to accumulate. The amount of fluid in the ventricles increases and the brain is then pushed outward.
Usually, the main symptom is an abnormally slow, unsteady, wide-legged walk. However, in some people, the feet seem to stick to the floor (called a magnetic gait). People also have urinary incontinence and a tendency to fall.
Dementia may not develop until late in the disorder. Often, the first sign of dementia is difficulty planning, organizing, putting ideas or doing actions for a task in the right order (sequencing), thinking abstractly, and paying attention. Memory tends to be lost later.
The diagnosis cannot be based on symptoms alone, particularly in older people. Other dementias can cause similar symptoms. Brain imaging (usually MRI) may detect excess cerebrospinal fluid, but this finding is also inconclusive, although it supports the diagnosis of normal-pressure hydrocephalus.
To help with the diagnosis, doctors do a spinal tap (lumbar puncture) to remove excess cerebrospinal fluid. If this procedure relieves symptoms, normal-pressure hydrocephalus is likely, and treatment is likely to be effective.
Treatment consists of placing a piece of plastic tubing (a shunt) in the ventricles of the brain and running it under the skin, usually to the abdomen (ventriculoperitoneal shunting). Cerebrospinal fluid is then drained away from the brain. The effects of this treatment may not be evident for several hours. This procedure may significantly improve the ability to walk and function and may lessen incontinence. However, mental function improves less and in fewer people. Thus, early diagnosis is important, so that people can be treated before dementia develops.
Dementia develops in many disorders.
About 40% of people with Parkinson's disease (see Movement Disorders: Parkinson's Disease) develop dementia, usually after age 70 and about 10 to 15 years after Parkinson's disease has been diagnosed. Dementia may be so severe that it is more disabling and causes death more often than any other effects of Parkinson's disease. People who have hallucinations and severe muscle and movement problems are most likely to develop dementia.
Symptoms may be very similar to those of Alzheimer's disease and Lewy body dementia. For example, memory is impaired, and people have difficulty processing information. People think more slowly. They may be apathetic and lack motivation. They may be moody, confused, disoriented and easily distracted.
Doctors diagnose Parkinson's disease dementia in people with Parkinson's disease when dementia develops years after motor symptoms. However, distinguishing dementia due to Parkinson's disease from Lewy body dementia can be difficult because symptoms are similar. Generally, Lewy body dementia is more likely if movement and muscle problems develop at the same time or shortly after the mental decline. Dementia due to Parkinson's disease is more likely if mental decline develops after movement and muscle problems in people with Parkinson's disease. Computed tomography (CT) and magnetic resonance imaging (MRI) may be done to rule out other causes of dementia.
Treatment involves general measures to provide safety and support, as for all dementias. Rivastigmine, a cholinesterase inhibitor, can be used to treat Parkinson's disease dementia.
This rare disease is a prion disease that causes a rapidly progressive dementia (see Prion Diseases: Overview of Prion Diseases). Creutzfeldt-Jakob disease often leads to severe dementia and death within a year. The most common early symptoms—memory loss and confusion—may resemble those of other dementias.
Variant Creutzfeldt-Jakob disease, thought to be acquired from eating beef contaminated with prions, causes a dementia similar to that due to Creutzfeldt-Jakob disease, except the first symptoms tend to be psychiatric symptoms (such as anxiety or depression) rather than memory loss.
No treatment is available.
In the late stages of human immunodeficiency virus (HIV) infection(see Human Immunodeficiency Virus HIV Infection), the virus may directly infect the brain. HIV damages nerve cells, causing dementia. Dementia may also result from other infections that people with HIV infection are prone to get. Unlike almost all other forms of dementia, it tends to occur in younger people.
This dementia usually begins subtly but progresses steadily over a few months or years. It usually develops after other symptoms of HIV infection. Symptoms of this dementia include slowed thinking and expression, difficulty concentrating, and apathy, but insight is not affected. Movements are slow, muscles are weak, and coordination may be impaired.
When HIV infection is diagnosed or when mental function changes in people with HIV infection, CT or MRI is done to check for a brain infection. Unless evidence suggests that pressure within the skull is increased, doctors usually do a spinal tap (lumbar puncture) to obtain a sample of cerebrospinal fluid for analysis and check for infection. Findings can support but not confirm the diagnosis of HIV-associated dementia.
Treatment with zidovudine and other drugs used to treat HIV infection sometimes produces dramatic improvement. However, because the infection is not cured, dementia may recur.
This disorder, also called chronic progressive traumatic encephalopathy, may develop in people who have repeated head injuries—boxers, for example. They often develop symptoms similar to those of Parkinson's disease, and some of them also develop normal-pressure hydrocephalus.
Last full review/revision February 2008 by Juebin Huang, MD, PhD