What is Lewy Body Dementia?
Lewy Body Dementia or LBD (also called Dementia with Lewy bodies, DLB) is a progressive form of dementia that causes declines in thinking, independent function and reasoning due to abnormal microscopic deposits that over time, damage brain cells. Although many people may not have heard of LBD, in the United States it affects approximately 1.4 million people and their families. LBD is the third most common cause of dementia behind vascular dementia and Alzheimer’s disease and accounts for 10-25% of dementia cases.
LBD symptoms are very similar to symptoms of other well-known diseases including Parkinson’s and Alzheimer’s disease, which is one reason it is highly underdiagnosed. Medical professionals unfamiliar with LBD do not know how to recognize the disease and it can take over a year for an adequate amount of symptoms to present themselves for a proper diagnosis. As early treatment of LBD can extend a person’s independence and quality of life, it is essential that medical professionals make a proper diagnosis as early as possible.
A Multisystem Disease
Lewy Body Dementia is a multisystem disease and an encompassing term for two related diagnoses of Parkinson’s disease dementia and dementia with Lewy bodies. Although the early symptoms of both diseases may be different, they have the same underlying biological modifications in the brain. A comprehensive treatment approach usually works best for LBD as people with LBD eventually develop similar behavioral, cognitive, sleep and physical symptoms. For a comprehensive approach to work on this multisystem disease to work, it requires a team of physicians from different specialties working together to treat each LBD symptom without making other symptoms worse. While many patients experience marked improvement in their symptoms with this approach, others may experience minimal change and some have extreme sensitivities or reactions to Alzheimer’s, Parkinson’s and other medications that require a different approach.
Frederick H. Lewy and his Research
Lewy Body Dementia received that name because of scientist named Frederick H. Lewy, M.D., who worked in Dr. Alois Alzheimer’s laboratory in the early 1900’s. While researching Parkinson’s disease, Dr. Lewy discovered the abnormal protein deposits disrupting the normal function of the brain. Scientists now link those abnormal protein deposits to LBD. The chief component of Lewy bodies is alpha-synuclein protein and it along with other body proteins exist in the brain stem area, depleting neurotransmitter dopamine, which causes symptoms similar to Parkinson’s disease. These abnormal proteins diffuse through other regions of the brain, such as the cerebral cortex, in LBD.
As the abnormal proteins of LBD move through the brain, it depletes the brain chemical called acetylcholine and disrupts thinking, behavior and perception. LBD can exist on its own or in conjunction with brain alterations often seen in Parkinson’s and Alzheimer’s disease. Patients with Parkinson’s may eventually experience problems with reasoning and thinking, while patients with LBD also experience movement issues including rigid muscles, hunched posture and difficulty moving. The overlapping symptoms of Parkinson’s and LBD indicate a possible link to the underlying abnormalities in the way the brain processes alpha-synuclein. Plaques and tangles (linked to Alzheimer’s disease) also exist within the brains of many patients with both Parkinson’s and LBD. Additional symptoms of LBD include:
- Alterations in reasoning and thinking
- Varying levels of alertness from one day to the next
- Issues processing visual information and/or visual hallucinations
- REM sleep disorder – sometimes violently acting out dreams
- Autonomic nervous system malfunctions
- Significant memory loss that is less prominent than present in Alzheimer’s disease
Lewy Body Dementia receives a “clinical” diagnosis today because there is no specific test that conclusively diagnoses dementia. A clinical diagnosis means that the doctors make their best professional judgment after evaluating symptoms in a patient. A conclusive diagnosis of LBD is only possible through an autopsy. Although experts today believe that Parkinson’s disease dementia and LBD are two different versions of similar underlying brain processing problems, many recommend a continued separate diagnosis of the disorders. Patients may receive a diagnosis of LBD when the following occur:
- LBD consistent dementia symptoms develop before other dementia form symptoms
- Both movement and dementia symptoms exist at time of diagnosis
- Dementia symptoms develop within a year following movement symptoms
Distinguishing Between LBD and Alzheimer’s Disease
It can be difficult to distinguish between LBD and Alzheimer’s disease because Lewy bodies often coexist with brain changes from Alzheimer’s especially in the early stages of the disease. There are however some significant differences between the two such as:
- Prominent memory loss early on – more common in early Alzheimer’s than early LBD
- Movement difficulties – more prominent in early LBD than early Alzheimer’s although they can develop in moderate to severe stages of Alzheimer’s
- Mental impairments – Delusions, hallucinations, REM sleep disorder and inability to identify familiar people more frequent in early LBD than early Alzheimer’s disease
- Autonomic nervous system disruption – blood pressure drop on standing, falls and dizziness more common in early LBD than early Alzheimer’s disease
Lewy Body Dementia Causes and Outcomes
Unfortunately, research has not found the specific causes of LBD yet as many people with the disease have no family history of it. Researchers have yet to conclusively identify any genes linked to LBD and no treatments exist that can stop or slow brain cell damage resulting from LBD. Today’s treatment plans focus on easing symptoms and there are currently over 100 studies underway to research Alzheimer’s and other dementias. When a treatment plan includes medications, a patient and their family need to collaborate with the doctor to find effective drugs for each symptom. Similar to Alzheimer’s disease and other dementias that destroy and damage brain cells, LBD worsens with time and decreases a person’s lifespan.