Diagnosing dementia with Lewy bodies

Currently there is no way of definitively diagnosing dementia with Lewy bodies, which can only be done with certainty by a brain autopsy after death. As a result dementia with Lewy bodies is often misdiagnosed.

However in June 2017, the International Dementia with Lewy Bodies Consortium, published updated diagnostic criteria, called the Consensus Guidelines  to help add greater weight to a probable / possible diagnosis.

New criteria for diagnosing dementia with Lewy bodies

In the guidelines, the symptoms, which are described as clinical features, are categorised as either central / core or supportive.

The central clinical feature is dementia and this must be present for a diagnosis of dementia with Lewy bodies i.e. a decline in the cognitive (thinking) abilities that interferes with everyday life.

There are four core clinical features, listed below.  If 2 or more of these symptoms are present then a probable diagnosis can be made. If only 1 is present then a possible diagnosis can be made.

  • Fluctuating cognition (awareness and concentration).
  • Recurrent visual hallucinations, such as seeing shapes, colours, people, or animals that aren’t there.
  • REM sleep behaviour disorder, which often presents years before the onset of dementia.
  • Parkinsonism (problems with movement).

Note: Fluctuating cognition and visual hallucinations detected early in the progression of dementia with Lewy bodies (as is often the case) can help differentiate from Alzheimer’s disease, where they do not tend to appear until the later stages.

In addition REM sleep behaviour disorder is highly associated with Lewy body disorders but not Alzheimer’s disease.

There are also a number of supportive clinical features which make a diagnosis more likely, as follows:

  • Severe sensitivity to anti-psychotic drugs.
  • Postural instability (poor balance).
  • Repeated falls.
  • Syncope (fainting).
  • Autonomic dysfunction e.g. constipation, falls in blood pressure, urinary incontinence.
  • Hypersomnia (excessive day time sleeping).
  • Hyposmia (reduced ability to smell and to detect odours).
  • Other types of hallucinations i.e. auditory.
  • Delusions
  • Mood changes i.e. apathy, anxiety and depression.

The guidelines also include 2 indicative and 2 supportive diagnostic bio-markers (e.g. brain scans to detect biological signs of disease). I haven’t included the bio-markers here as they are very technical and therefore fairly meaningless to most people.  However bio-markers help support the diagnosis of dementia with Lewy bodies.  In cases where only 1 core clinical feature is present but 1 indicative bio-marker is also present then a probable diagnosis can be given. If 1 or more indicative bio-marker is present with no core clinical features then a possible diagnosis can be made.

Diagnosing dementia with Lewy bodies

Our struggle to obtain a diagnosis of dementia with Lewy bodies

It took us around 3 years to obtain a diagnosis of dementia for Mum, although originally she was incorrectly diagnosed as having vascular dementia mixed with Alzheimer’s disease. Fortunately, Mum was eventually assigned to a consultant psychiatrist who knew a lot about Lewy body dementia and after one visit (during which she exhibited many of the clinical features associated with dementia with Lewy bodies) he changed the diagnosis.

Our struggle to obtain a diagnosis involved many trips to the doctor trying to explain the problem, not helped by Mum who refused to accept there was one!! The doctor was convinced that Mum was suffering from depression. We finally persuaded Mum to take the standard mini-mental state examination (MMSE), which she passed further convincing the doctor that depression was the issue.

At the time I had never even heard of dementia with Lewy bodies and I couldn’t understand why Mum functioned so well in some situations i.e. could pass an MMSE test but she couldn’t make a cup of tea. Of course, I now understand that memory is often unaffected in the earlier stages of the disease and that people have more trouble with problem-solving and performing a sequence of tasks in the correct order.

Throughout her illness, Mum suffered from every single one of the clinical features mentioned above and she suffered from REM sleep behaviour disorder for decades before the onset of her dementia. If I had known about dementia with Lewy bodies and the listed clinical features above, I would have been able to persuade the doctor and obtained a correct probable diagnosis much sooner. And had that happened the journey would have been much easier for all of us.

You can read about our journey from the early stages of Mum’s illness, the struggles we faced and the memories we cherish in the book I wrote as a way to help me through my grief following Mum’s death in 2016.

The Lewy Body Dementia Association have created a very useful ‘Diagnostic Symptoms Checklist’ which you can complete and take along to your doctor if you are worried that you or a loved one may have dementia with Lewy bodies.

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