Lewy
body Dementia
Introduction
Alzheimer's disease is the most common of a large group of disorders known as "dementias." It is an irreversible disease of the brain in which the progressive degeneration of brain cells causes thinking ability and memory to deteriorate. Alzheimer's disease also affects behaviour, mood and emotions, and the ability to perform daily living activities.
There is currently no cure for Alzheimer's disease, but there are treatment options and lifestyle choices that can slow its progression and, within the next five years, treatments are expected that may well stop the disease in its tracks! Also, the pursuit of new research strategies should one day help restore some lost function and memory.
Alzheimer's disease progresses through early, middle and late stages before reaching the final end of life stage. However, identifying the transition from one stage to another is often difficult. Not only does the disease usually progress slowly, but the symptoms related to each stage tend to overlap and the order in which they appear and how long they last varies from person to person.
The duration following diagnosis is usually seven to ten years. However, when the diagnosis is delayed, as it may be if the affected person fails to see a doctor early on, the disease duration is shorter than this. Conversely, as the ability to diagnose Alzheimer's disease improves and people become more willing to be assessed, survival times following diagnosis are lengthening.
"Related dementias" resemble Alzheimer's disease in that they also involve a progressive degeneration of brain cells that is currently irreversible. They include the dementia associated with Vascular Dementia (the second most common dementia after Alzheimer's disease), Frontotemporal Dementia, Creutzfeldt-Jakob Disease, Lewy body Dementia, Parkinson's disease, and Huntington disease.
Sometimes a person may have symptoms such as sudden onset of memory loss, behaviour changes, or difficulties with speech and movement. These symptoms may suggest a dementia other than Alzheimer's disease. Lewy body Dementia is one of these dementias. In any event a person should always seek a thorough medical assessment if any of these symptoms are present.
Regardless of the type of dementia, individuals are encouraged to obtain information and support from the Alzheimer Society.
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 body Dementia.
Lewy body Dementia can occur by itself, or together with Alzheimer's disease or Parkinson's. It accounts for 5-15% 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 disease. 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 disease 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 Lewy body Dementia, there may be an increased risk of developing the disease. Lewy body Dementia is more common in men than in women.
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 disease, 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's disease 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:
[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.]
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