Dementia is a progressive (gradually worsening) decline of mental abilities that disturbs "cognitive" functions such as memory, thought processes, and speech as well as behavior, and movements. Dementia with Lewy bodies (DLB) is the name for a group of disorders in which dementia is caused by the presence of Lewy bodies in the brain. Lewy bodies are small round clumps of normal proteins that for unknown reasons become abnormally clumped together inside neurons (brain cells). Whether the Lewy bodies directly cause gradual degeneration (damage) to the brain cells, impairing their function and eventually killing them, or are only a marker of some other destructive process is not known.
Lewy bodies are named after Frederich Lewy, the doctor who first described them in 1912. Dr. Lewy first found Lewy bodies in the brains of people with Parkinson disease. Parkinson disease is a condition best known for disrupting body movements. The most common of these "motor" symptoms are tremor (shaking or trembling) of the hands (that mainly occurs when the hands are at rest and not moving), rigidity (stiffness) of the trunk and limbs, slowness of movement, and loss of balance and coordination. Estimates vary from 30-60% about what percentage of people with Parkinson disease develop dementia.
Scientists later discovered cases of Alzheimer-type dementia linked to Lewy bodies. This was thought to be very rare, but as tests of brain tissue improved, it became clear that Lewy bodies were fairly common and were linked to several different types of dementia. A type of dementia similar to but different from Alzheimer disease was recognized and called DLB. DLB is now believed to be the second or third most common type of dementia after Alzheimer disease, accounting for about 10-20% of all dementias. (There is controversy about whether DLB or vascular dementia is the second most common form of dementia.)
The relationship between DLB and Parkinson disease is not completely understood. When motor symptoms appear first and predominate over cognitive symptoms, the diagnosis is believed to be Parkinson disease. When cognitive impairment and behavioral disturbances are prominent early symptoms, DLB is believed to be the diagnosis.
DLB is a disease of aging. People affected by DLB are usually elderly or in late middle age.
We do not know why Lewy bodies form in the brain.
Symptoms vary from person to person with DLB. The one characteristic common to everyone with DLB is progressive loss of mental abilities that interferes with everyday activities. This may include the following:
Dementia symptoms can have many different causes. Some underlying causes are reversible with treatment, others are not, but treatment is often still helpful. It is very important that all reversible causes be ruled out and that the type of dementia be diagnosed correctly, as treatment and outlook vary by type.
At this time, there is no foolproof way to confirm DLB in a living person. Definitive diagnosis of DLB is possible only after death. Examination of brain tissue at autopsy is the only way to confirm the presence of Lewy bodies. Certain chemical tests are applied to the tissue. One test detects alpha-synuclein, the major protein component of the Lewy bodies. Therefore, DLB is what medical professionals call a "clinical diagnosis." This means that the diagnosis is made on the basis of your symptoms, your medical history, your test results, and in some cases even your response to treatment. This method is based on detecting signs that may be very subtle and on the probabilities of your having a specific condition.
If you or a loved one is having dementia symptoms, your health care provider's job is to gather all the relevant information to make an accurate diagnosis. The first step is the medical interview. You will be asked questions about your symptoms and how they have developed over time, your medical problems now and in the past, medications, family medical problems, work and travel history, and habits and lifestyle. If you have trouble answering the questions, a family member or friend may be asked to fill in missing details. A thorough physical examination, including a mental status examination, will look for signs that might indicate the underlying cause of the dementia.
Neuropsychological testing
There is no definitive medical test that confirms dementia or DLB. The most accurate way to measure cognitive decline is through neuropsychological testing.
Lab tests
There is no specific lab test for DLB. Lab tests of your blood may be needed to rule out certain causes of dementia, such as infection, metabolic disorders (such as thyroid imbalance), or medication effects. Basic tests may be done to check your overall level of general health.
Imaging studies
An imaging study of the brain is useful in determining the underlying cause of dementia. MRI is sometimes preferred to CT scan, because it affords greater detail of the brain. Although Lewy bodies cannot be detected on these images, other causes of dementia such as stroke can be ruled out. These images also can detect brain atrophy (shrinkage). The degree of atrophy can be useful in making a diagnosis.
Other tests
There is no cure nor treatment that stops or slows DLB. Treatment is aimed at relieving symptoms and delaying loss of mental abilities for as long as possible.
An individual with DLB should always be under medical care. Much of the day-to-day care, however, is handled by family caregivers. Medical care should focus on optimizing the individual’s health, safety, and quality of life while helping family members cope with the many challenges of caring for a loved one with DLB.
People with DLB usually can remain at home with their families. They require close supervision because they can fall or faint. They should be checked often by their medical team to monitor the effects of treatment and make changes if needed.
Individuals with DLB should remain physically, mentally, and socially active as long as they are able.
A balanced diet that includes plenty of fruits and vegetables will help maintain a healthy weight and prevent malnutrition and constipation. An individual with DLB should not smoke, both for health and safety reasons.
|Medical Treatment|Drug treatment is the mainstay of therapy for DLB. The treatment of DLB is much like that of Alzheimer disease or Parkinson disease.
Acetylcholinesterase inhibitors (see Medication) may decrease confusion and cognitive fluctuations in DLB. These drugs generally do not worsen motor symptoms. These drugs also may be used for treatment of agitation and hallucinations associated with DLB. (When these symptoms are mild, however, no medical treatment may be necessary.)
An atypical neuroleptic (antipsychotic) drug typically is the first choice for treatment of hallucinations and agitation. Treating these symptoms is especially important because they can result in unsafe behavior, accidents, and injuries. Standard antipsychotic drugs such as haloperidol (Haldol) should be avoided because many people with DLB are extremely sensitive to these drugs.
Drugs that increase levels of the neurotransmitter dopamine are widely used to relieve the motor symptoms of Parkinson disease. These drugs may improve motor function in some people with DLB. In many people, however, these drugs have no effect and may make cognitive symptoms worse, especially hallucinations.
Depression is very common in DLB and may result from brain damage and/or as a psychological response to impaired function. Selective serotonin reuptake inhibitors (SSRIs) are the drugs of choice. Another type of antidepressant called a monoamine oxidase-B inhibitor (MAOI) has been tried, alone or in combination with SSRIs or tricyclic antidepressants. Such combinations are not usually recommended because they can have severe side effects, especially in older people.
Some research studies have suggested that vitamin E, an antioxidant, may slow the rate of progression of Alzheimer diseases. Therefore, vitamin E has been tried in DLB. We do not yet have proof that this agent works in DLB.
Medications can be used to relieve depression, treat agitation and hallucinations, and improve cognition and/or alertness. There is a great deal of controversy about whether or not acetylcholinesterase inhibitors may slow the rate of cognitive decline or slow the need for nursing home placement.
Acetylcholinesterase inhibitors: These drugs increase the level of acetylcholine in the brain, which is low in DLB. These drugs can decrease fluctuations in cognition, increase alertness, and improve memory. Examples include donepezil (Aricept), tacrine (Cognex), rivastigmine (Exelon), and galantamine (Reminyl).
Atypical neuroleptics: These drugs can relieve hallucinations, delusions, and agitation. They do not worsen motor symptoms as much as "typical" older neuroleptic drugs do. Examples include risperidone (Risperdal), olanzapine (Zyprexa), and quetiapine (Seroquel).
Antidepressants: The first choice for treatment of depression in DLB is the selective serotonin reuptake inhibitors, which do not deplete acetylcholine. Examples include sertraline (Zoloft), fluoxetine (Prozac), venlafaxine (Effexor), and paroxetine (Paxil).
Dopamine-promoting drugs: These drugs work in various ways to increase the level of the neurotransmitter dopamine in the brain. Although low dopamine level is partly responsible for the motor symptoms of DLB, these drugs often cannot be tolerated because of the side effects. They can, for example, worsen hallucinations. Examples include combined levodopa and carbidopa (Sinemet), which combines a dopamine precursor with a drug that maximizes its usefulness in the brain, and pramipexole (Mirapex) and ropinirole (Requip), which mimic the effects of dopamine.
Antioxidants: These agents counteract excess oxidation, which may contribute to the brain cell damage in DLB. Formal studies are lacking to determine their usefulness in slowing the disease progression. The only example now in widespread use is alpha-tocopherol, or vitamin E (Vita-Plus E Softgels, Vitec, Aquasol E).
After DLB has been diagnosed and treatment begun, the individual requires regular check-ups with his or her health care provider.
There is no known way to prevent DLB. Being alert for symptoms and signs may allow earlier diagnosis and treatment. Appropriate treatment can slow or relieve symptoms in some people.
|Outlook|Like other types of degenerative dementia such as Alzheimer disease, DLB is gradually progressive.
If you are a caregiver for a person with DLB, you know that the disease tends to be more stressful for the family members than for the affected person. Caring for a person with dementia can be very difficult. It affects every aspect of your life, including family relationships, work, financial status, social life, and physical and mental health.
This is why support groups were invented. Support groups are groups of people who have lived through the same difficult experiences and want to help themselves and others by sharing coping strategies. Mental health professionals strongly recommend that family caregivers take part in support groups. Support groups serve a number of different purposes for a person living with the extreme stress of being a caregiver for a person with DLB:
Alzheimer’s Association
225 N. Michigan Avenue, Fl. 17
Chicago, IL 60601
(800) 272-3900
Alzheimer’s Disease Education and Referral Center (ADEAR)
National Institute on Aging
P.O. Box 8250
Silver Spring, MD 20907-8250
(800) 438-4380
(301) 495-3311
National Institute for Neurological Diseases and Stroke
National Institutes of Health
Bethesda, MD 20892
National Parkinson Foundation, Inc.
Bob Hope Parkinson Research Center
1501 NW 9th Avenue
Bob Hope Road
Miami, FL 33136-1494
(800) 327-4545
(305) 547-6666
Parkinson's Disease Foundation
710 West 168th Street
New York, NY 10032-9982
(800) 457-6676
Alzheimer’s Association
Alzheimer’s Disease Education & Referral Center
BrainTalk Communities
Family Caregiver Alliance, National Center on Caregiving
Lewy Body Dementia Association, Inc.
National Institute for Neurological Diseases and Stroke, National Institutes of Health, NINDS Dementia With Lewy Bodies Information Page
National Parkinson Foundation, Inc.
Parkinson's Disease Foundation
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