Dementia with Lewy Bodies (DLB) is a progressive degenerative disease or syndrome of the brain. It shares symptoms,and sometimes overlaps, with several diseases, especially Alzheimer's and Parkinson's.
People who develop DLB have behavioral and memory symptoms of dementia like those of Alzheimer's Disease and, to varying extents, the physical, motor system symptoms seen in Parkinson's Disease. However, the mental symptoms of a person with DLB might fluctuate frequently, motor symptoms are milder than for Parkinson's, and DLB patients usually have vivid visual hallucinations.
Dementia with Lewy Body (DLB) is also called "Lewy Body Dementia" (LBD), "Diffuse Lewy Body Disease", "Lewy Body Disease", "Cortical Lewy Body Disease", "Lewy Body Variant of Alzheimer's Disease" or "Parkinson's Disease Dementia." It is the second most common dementia, accounting for 20% of those with dementia (Alzheimer's Disease is first). Dementia is a gradual, progressive decline in mental ability (cognition) that affects memory, thinking processes, behavior and physical activity. In addition to these mental symptoms, persons with DLB experience physical symptoms of parkinsonism, including mild tremor, muscle stiffness and movement problems. Strong visual hallucinations also occur.
DLB is named after smooth round protein lumps (alpha-synuclein) called Lewy bodies, that are found in the nerve cells of the affected parts of the brain. These "abnormal protein structures" were first described in 1912 by Frederich Heinrich Lewy, M.D., a contemporary of Alois Alzheimer who first identified the more common form of dementia that bears his name.
Lewy bodies are found throughout the outer layer of the brain (the cerebral cortex) and deep inside the midbrain and brainstem. They are often found in those diagnosed with Alzheimer's, Parkinson's, Down syndrome and other disorders.
The cause of DLB is unknown and no specific risk factors are identified. Cases have appeared among families but there does not seem to be a strong tendency for inheriting the disease. Genetic research may reveal more information about causes and risk in the future. It usually occurs in older adults between 50-85 years old and slightly more men than women have the disease.
Initial symptoms of DLB usually are similar to those of Alzheimer's or Vascular Dementia and are cognitive in nature, such as acute confusion, loss of memory, and poor judgment. Other patients may first show the neuromuscular symptoms of parkinsonism—loss of spontaneous movement, rigidity (muscles feel stiff and resist movement), and shuffling gait, while still others may have visual hallucinations as the first symptom. Patients may also suffer from delusions or depression.
Movement and motor problems occur in later stages for 70% of persons with DLB. But for 30% of DLB patients, and more commonly those that are older, Parkinson's symptoms occur first, before dementia symptoms. In these individuals, cognitive decline tends to start with depression or mild forgetfulness.
Dementia with Lewy bodies is difficult to diagnose. Not only does it resemble other dementias, it overlaps with Alzheimer's, Parkinson's and other disorders which may result in it being difficult to rule out or exclude. Because no single test exists to diagnose DLB, a variety of medical, neurological and neuropsychological tests are used to pinpoint it and its possible overlap with other illnesses. A definitive diagnosis can only be made by an autopsy at death. There are no medications currently approved to specifically treat DLB.
Although Lewy bodies are found in brains of patients with other diseases, and because testing will involve several approaches, it is useful to understand what happens to the brain of a person with DLB. Three significant changes or pathological features are seen in brains afflicted by DLB:
None of the symptoms of Dementia with Lewy Bodies is specific only to DLB. To address this problem, an international group of researchers and clinicians developed a set of diagnostic criteria in 1995, called the Consensus Guidelines that can reliably point to DLB:
Must be present:
Two of the following are present (one also indicates possibility of DLB):
A DLB diagnosis is even more likely if the patient also experiences repeated falls, fainting, brief loss of consciousness, delusions, or is sensitive to neuroleptic medications that are given to control hallucinations and other psychiatric symptoms.
Finally, the timing of symptoms is a reliable clue: if both mental and motor symptoms appear within one year of each other, DLB is more likely the cause. Signs of stroke or vascular dementia usually negate the likelihood of DLB.
Testing is usually done to rule out other possible causes of dementia. Brain imaging (CT scan or MR imaging) can detect brain shrinkage and help rule out stroke, fluid on the brain (normal pressure hydrocephalus), or subdural hematoma. Blood and other tests might show vitamin B 12 deficiency, thyroid problems, syphilis, HIV, or vascular disease. Depression is also a common cause of dementia-like symptoms. Additional tests can include an electroencephalogram (EEG) or spinal tap. Scans using SPECT or PET technology have shown promise in detecting differences between DLB and Alzheimer's disease.
DLB's similarity to Alzheimer's and Parkinson's diseases and the fact that Lewy bodies are often found in the brains of patients with these diseases means that clinicians must pay close attention to the factors that distinguish DLB:
Despite these differences, a diagnosis of Dementia with Lewy Bodies does not preclude a positive diagnosis of Alzheimer's, Parkinson's or other diseases common in older age.
With an average lifespan after onset of 5 to 7 years, the progress of Dementia with Lewy Bodies is relentless; however, the rate of decline varies with each person. DLB does not follow a pattern of stages as is seen in some other dementias. Death usually occurs from pneumonia or other illness. There is neither cure nor specific treatment to arrest the course of the disease.
Caution must be used in treating a person with DLB. Medications must be monitored closely for proper balance because some patients are adversely affected by some drugs. Neuroleptic (tranquilizing) anti-psychotic medications such as haloperidol (Haldol) or thioridazine (Mellaril), as well as benzodiazepines (Valium, Ativan) and anti-histamines can cause extreme adverse reactions in DLB patients. Side effects include motor related symptoms, catatonia (non-responsiveness), loss of cognitive function and/or development of muscle rigidity. These medications are sometimes used in Alzheimer's patients to help with hallucinations and behavioral symptoms, but should not be used in patients with DLB. Levodopa may be given to treat the parkinsonism, however, it may increase the hallucinations of DLB patients and aggravate other symptoms, such as cognitive functioning. It is less effective in treating tremor in DLB patients than in Parkinson's patients. Aricept or other cholinesterase inhibitors are given to treat the hallucinations. Some anti-depressants have shown positive results, while others are counter indicated.
When considering surgery, families should meet with the anesthesiologist to discuss possible side effects of anesthesia, as DLB patients are prone to delusions and a decline in motor functioning after anesthesia.
DLB patients can live at home with frequent reassessment and careful monitoring and supervision. Caregivers must watch the patient closely because of the tendency for them to fall or lose consciousness. Particular care should be taken when a patient is standing up from a chair or getting out of bed, as blood pressure can drop, causing the patient to lose his or her balance. Dementia prevents patients from learning new actions that might help them overcome movement problems, such as learning to use a walker. They may need more assistance some days than others, and can be reassured by a caregiver's help in turning attention away from the hallucinations.
Caregivers must learn to navigate both skills in dealing with cognitive, behavioral and motor disabilities. Attending support groups and learning skills in how to communicate with someone with dementia as well as learning skills in helping someone with a motor disorder will reduce caregiver stress and frustration.
Caregivers can turn to a California Caregiver Resource Center for assistance and to a qualified diagnostic center for initial diagnosis and follow up. In other states, resources can be found through local and state offices on aging and health such as your Area Agency on Aging or the Alzheimer's Association in your area.
Lewy Body Dementia Association. P.O. Box 451429. Atlanta, GA 31145. (404) 422-5434. www.lbda.org
Riding the Roller Coaster with Lewy Body Dementia by Helen Whitworth, available by calling (480) 981-1117.
LewyNet, The University of Nottingham, Division of Pathology, University Park, Nottingham, England NG7 2RD. Telephone +44 115 9515151. Web site: http://www.nottingham.ac.uk/pathology/lewy/lewyinfo.html
"Dementia with Lewy Bodies: A Distinct Non-Alzheimer Dementia Syndrome?" by Paul G. Ince, Elaine K. Perry, and Chris M. Morris, Brain Pathology, April, 1998. (Available with extensive bibliographies at LewyNet web site.)
"Similarities to Alzheimer's and Parkinson's Make Lewy Body Dementia Difficult to Recognize and Challenging to Treat," John Douglas French Center for Alzheimer's Disease Journal, 1998/1999.
Parkinson's Disease UPDATE, a monthly newsletter, Medical Publishing Company, P. O. Box 450, Huntingdon Valley, PA 19006. Issue #10, 2000.
"Dementia with Lewy Bodies" by Ian G. McKeith, M.D., FRCPsych., High Notes, News from the John Douglas French Alzheimer's Foundation, Fall, 1996.
"Consensus guidelines for the clinical and pathological diagnosis of dementia with Lewy bodies (DLB): report of the consortium on DLB International Workshop," by I. G. McKeith, D. Galasko, K. Kosaka, E. K. Perry, et al, 1996. Neurology, 47:1113-24.
Dementia with Lewy Bodies by Robert H. Perry, Ian G. McKeith, and Elaine K. Perry (editors), Forward by Jeffrey L. Cummings, 1996. Cambridge University Press, Cambridge.
Family Caregiver Alliance
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(415) 434-3388 or
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E-mail: [email protected]
Web Site: caregiver.org
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Family Caregiver Alliance (FCA) seeks to improve the quality of life for caregivers through education, services, research and advocacy.
FCA's National Center on Caregiving offers information on current social, public policy and caregiving issues; provides assistance in the development of public and private programs for caregivers; publishes timely reports, newsletters and fact sheets; and assists caregivers nationwide in locating resources in their communities.
For residents of the greater San Francisco Bay Area, FCA provides direct family support services for caregivers of those with Alzheimer's disease, stroke, ALS, head injury, Parkinson's and other debilitating health conditions that occurs most often in adults.
Lewy Body Dementia Association.
P.O. Box 451429. Atlanta, GA 31145. (404) 422-5434.
Reviewed by William Jagust, MD and prepared by Family Caregiver Alliance. February 2001. Updated June, 2010. Funded by the Alameda County Area Agency on Aging and the California Department of Mental Health. ©2010 All rights reserved.