Lewy body dementia
(Content reproduced with permission from the Alzheimer Society of Canada)
What is Lewy body Dementia?
Lewy body Dementia is a form of dementia characterized by abnormal deposits
of a protein called alpha-synuclein that form inside the brain's nerve cells.
These deposits are called "Lewy bodies" after the scientist who first
described them. The process that leads to the formation of Lewy bodies is unknown.
Areas of the brain involved in thinking and movement are most affected in Lewy
Lewy body Dementia can occur by itself, or together with Alzheimer's disease
or Parkinson's. It accounts for 15-20% of all dementias.
Other names for Lewy body Dementia include:
• Diffuse Lewy body Disease
• Cortical Lewy body Disease
• Lewy body Disease
• Senile Dementia of Lewy Type
• Dementia with Lewy bodies
• Lewy body variant of Alzheimer's disease
How does Lewy body Dementia affect the person?
In Lewy body Dementia, a person may experience symptoms similar to those of
both Parkinson's and Alzheimer's disease. A progressive loss of memory, language,
reasoning and other higher mental functions such as calculation of figures is
common. The person may have difficulty with short-term memory, finding the right
word and sustaining a train of thought. An individual may also experience depression
and anxiety. Marked fluctuations in alertness may also be experienced.
Lewy body Dementia usually has a rapid progression. Memory difficulties may
not be an early symptom, but can develop as Lewy body Dementia progresses. Visual
hallucinations (seeing things which are not real) are common and can be worse
during times of increased confusion. The visual hallucinations are often recurrent
and typically consist of people, children or animals. People with the disease
may also make errors in perception, for example, seeing faces in a carpet pattern.
Some features of Lewy body Dementia can resemble Parkinson's. These include
rigidity (stiffness of muscles), tremors (shaking), stooped posture and slow,
shuffling movements. Sensitivity to medication, especially some sedatives, may
exaggerate these symptoms.
How is Lewy body Dementia assessed?
No single test can diagnose Lewy body Dementia. Doctors diagnose the disease
through a process of eliminating other diseases and conditions that can cause
similar symptoms. Assessment may include a neurological exam that emphasizes
gait, posture and the degree of rigidity.
What are the risk factors for Lewy body Dementia?
At present, there is no known cause of Lewy body Dementia and risk factors
have not been identified. However, Lewy bodies contain a protein associated
with Parkinson's and are often found in the brains of people with Parkinson's
or Alzheimer's disease, suggesting that the three conditions may be linked in
some way. If a family member has the disease, there may be an increased risk
of developing the disease. Lewy body Dementia is more common in men than in
Is there treatment?
At present, there is no cure for Lewy body Dementia. It is sometimes possible
to use medications to treat symptoms such as those associated with Parkinson's,
depression, and unpleasant hallucinations. Cholinesterase inhibitors are medications
used in treating Alzheimer's disease. They can improve alertness and cognition
in some people and may reduce hallucinations and other distressing symptoms.
However, due to the multiple features of Lewy body Dementia and Parkinson symptoms,
treatment of one symptom may be achieved by worsening another. One strategy
to avoid or prevent this is to treat symptoms in order of their severity.
For more information:
• Call your local
• Lewy Body Dementia Association Inc.
(The contents of this document are provided for information purposes only,
and do not represent advice, an endorsement or a recommendation, with respect
to any product, service or enterprise, and/or the claims and properties thereof,
by the Alzheimer Society of Canada. The Information Sheet is not intended to
replace clinical diagnosis by a health professional.)