What Is Lewy Body Dementia?
Lewy body
dementia is a progressive condition that causes dementia or psychosis. It is named for the abnormal structures (Lewy bodies) found in certain areas of the brain. Lewy body dementia is the second most common type of degenerative dementia found in the elderly.
It should be noted that Lewy body dementia is often referred to both as a type and a cause of dementia. Likewise, terms such as "vascular dementia" are often used to describe causes as well as
types of dementia.
Lewy bodies and many of the symptoms of Lewy body dementia are often associated with
Parkinson's disease and
Alzheimer's disease. Therefore, researchers do not yet understand whether Lewy body dementia is its own condition or perhaps a variant of
Alzheimer's or Parkinson's disease.
Lewy body dementia usually occurs sporadically in people with no known family history of Lewy body dementia. However, familial cases have occasionally been reported.
Other names for Lewy body dementia include:
- Dementia with Lewy bodies
- Lewy body disease
- Diffuse Lewy body disease
- Cortical Lewy body disease
- Lewy body variant of Alzheimer's
- Parkinson's disease with dementia.
Understanding Dementia and the Brain
In Lewy body
dementia, cells die in the brain's cortex (outer layer) and in a part of the mid-brain called the substantia nigra. Many of the remaining nerve cells in the substantia nigra contain abnormal structures called Lewy bodies that are the hallmark of this type of dementia. Lewy bodies may also appear in the brain's cortex (outer layer).
Lewy bodies contain a protein called alpha-synuclein that has been linked to
Parkinson's disease and several other disorders.
Dementia research scientists, who sometimes refer to these disorders collectively as "synucleinopathies," do not know why this protein accumulates inside nerve cells people with Lewy body dementia.
Symptoms of Lewy Body Dementia
The symptoms of Lewy body dementia can vary among individuals. They also can vary during the different stages of the disease, or even from hour to hour or day to day. Some people with Lewy body dementia will have traditional parkinsonian effects, such as:
- Loss of spontaneous movement
- Rigidity (muscles feel stiff and resist movement)
- Tremor
- Shuffling gait.
These symptoms are usually mild or even absent during the early stages of Lewy body dementia; as the disease progresses, these symptoms become more common. Rigidity will usually be severe.
Other people with Lewy body dementia may have symptoms similar to those seen with
Alzheimer's disease. These symptoms could include:
- Acute confusion
- Loss of memory
- Loss of (or fluctuating) cognition.
Visual hallucinations may be one of the first Lewy body dementia symptoms people experience, and they may suffer from other psychiatric disturbances such as delusions and
depression.
Other symptoms of Lewy body disease can include:
- Difficulty swallowing
- Repeated falls
- Lightheadedness, dizziness, or fainting (syncope)
- Low blood pressure, especially when going from sitting to standing
- Erectile dysfunction (also known as ED or impotence)
- Constipation
- Dry eyes or mouth
- Unexplained loss of consciousness.
- Autonomic dysfunction.
Although Lewy body dementia usually occurs in older adults, younger people can be affected as well.
There is no cure for Lewy body
dementia. Treatments are aimed at controlling the parkinsonian and psychiatric symptoms associated with Lewy body dementia. Patients with Lewy body dementia sometimes respond dramatically to treatment with antiparkinsonian drugs, cholinesterase inhibitors (such as those used to treat
symptoms of Alzheimer's disease), or both of these types of drugs. Some examples of medications for
Parkinson's disease that may be used for Lewy body dementia include:
However, antiparkinsonian medication that may help to reduce tremor and loss of muscle movement might actually worsen symptoms such as hallucinations and delusions.
Some examples of cholinesterase inhibitor medicines that may be used for Lewy body dementia include:
Some studies indicate that neuroleptic drugs, such as
clozapine (FazaClo
®) and
olanzapine (
Zyprexa®), can also reduce the psychiatric symptoms associated with Lewy body dementia. However, because neuroleptic drugs may cause severe adverse reactions, doctors usually try other therapies first. In the event that healthcare providers do recommend neuroleptic drugs, they will typically monitor patients taking such medications closely.
Lewy body dementia is a slowly progressive condition that results in progressive intellectual and functional deterioration. There is no cure, nor are there any known treatments to stop or slow the progression of Lewy body dementia. Patients with Lewy body dementia live an average of seven years after symptoms begin.
Lewy Body Dementia, Alzheimer's Disease, and Parkinson's Disease
Lewy bodies are often found in the brains of people with Parkinson's and
Alzheimer's disease. These findings suggest that Lewy body
dementia is related to these other
causes of dementia or that the diseases sometimes coexist in the same person.
