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Lewy Body Disease

Information for patients and carers

What is Lewy Body Disease?
Lewy Body Disease is a physical disease of the brain that sometimes leads to alterations in thinking (intellect) and behaviour.

What are the symptoms?
People with Lewy Body disease have problems with concentration and memory, and may seem inattentive and distractible.  A fluctuating confusion is common: patients may seem confused and incoherent at times, but quite lucid at others.  During periods of confusion remarks may seem off the point and irrelevant, although usually the person uses real words and pronounces them correctly.  Hallucinations are common: patients may believe that other people are in the house, or they may see animals that are not present.

Why do people with Lewy Body disease have hallucinations?
We do not have a complete explanation.  However, they are likely to relate in part to problems in visual perception.  The regions at the back of the brain are particularly important for processing visual information – for making sense of what we see.  When this part of the brain is damaged then people can still see (i.e. their eyesight is not affected), but they have problems in interpreting visual stimuli and sometimes identify things incorrectly (e.g. they may think that a pattern in a curtain or carpet is the face of a person).  We know that this part of the brain, responsible for interpreting visual information, is affected in Lewy Body disease. 

Are the mental symptoms the same as in Alzheimer’s disease?
Some of the intellectual changes are similar and there is a recognised overlap between the two conditions.  However, the fluctuating confusion and distractibility is particularly characteristic of Lewy Body disease.  Hallucinations are more common in Lewy Body disease than Alzheimer’s disease.

Are people with Lewy Body Disease sometimes thought to have Alzheimer’s disease initially?
Yes. The reason is that there is an overlap between the two disorders. Patients share common cognitive symptoms and there are some common brain changes. Because of the link between the two disorders doctors may sometimes use the term “Lewy body variant of Alzheimer’s disease”.

Are the mental changes the only symptoms?
No.  People with Lewy Body disease also slow down physically and develop stiffness of the limbs.  The physical symptoms are similar to those of Parkinson’s disease.

Do the physical or mental symptoms occur first?
People vary with regard to the development of symptoms.  Some people develop changes in thinking first and may have no physical symptoms for months or years.  Other people develop the physical changes or Parkinson’s disease first, with no mental symptoms, and then develop mental changes only much later.  People in the latter group will normally be diagnosed as suffering from Parkinson’s disease until the mental changes develop. 

Does that mean that Lewy Body disease is a form of Parkinson’s disease?
Yes.  The difference is that whereas in Parkinson’s disease the brain changes are confined to deep structures within the brain important for the control of movement, Lewy Body disease also affects the “cortex” – the outer parts of the brain important for thinking.  As noted above, Lewy Body disease tends to damage the back part of the cortex, responsible for making sense of what we see.

Will the symptoms become worse?
The disease is progressive, so symptoms do worsen over time.  However, there is wide variation in the speed of progression.  Some people show little decline over the course of a year whereas others change more quickly.  Usually, monitoring a person’s progress over a year will give a good guide as to the likely future rate of progression.

At what age do people become affected?
Lewy body disease becomes more common as people get older, although it may also affect people in middle age.

What is the cause?
The disorder is a degenerative condition of the brain. This means that cells in certain parts of the brain gradually cease  to function properly, which is why symptoms develop. The cause of this degeneration is at present not fully understood and is the key question for current research. However we know that this condition is not caused by external environmental or lifestyle factors, such as diet, occupational exposure or head injury. It can affect people from all walks of life and is not simply the result of ‘over-use’ or ‘under-use’ of the brain.

Is Lewy Body Disease inherited?
No, not typically. Cases of inherited Lewy Body Disease are extremely rare.

Are there any treatments?
Current treatments do not provide a cure for the disease. However, there are drugs available, which are designed to alleviate symptoms and slow the progression of the disease.

Why haven’t I heard of Lewy Body disease before?
It is only quite recently that it has been recognised as a specific entity. 

Is there any research into Lewy Body disease?
Yes, certainly. The interest in this area of research increases each year. The aim is to understand the mechanisms that underlie this disorder, so that better treatments can be developed. Our department is an active contributor to research in Lewy Body Disease and other degenerative disorders. If you would like to find out more about the research carried out in our unit, please visit our website or ask when you attend the clinic.