Dementia is caused by different diseases, dementia with Lewy bodies is the third most common disease that causes dementia.

What is dementia with Lewy bodies?

The word dementia is used to describe a group of symptoms. These include memory loss, confusion and changes to communication, mood, and behaviour. These symptoms affect day-to-day life. For every 100 people who have dementia, about 10-15 will have dementia with Lewy bodies. This means that around 100,000 people in the UK have this type of dementia.

Sometimes dementia with Lewy bodies is also called DLB.

DLB is caused by small round clumps of protein that build up inside nerve cells in the brain. One of these proteins is called alpha-synuclein, and the clumps it forms are called Lewy bodies. Lewy bodies damage the nerve cells, and this damage affects the way that our brain cells communicate. In DLB, the nerve cells that are affected are in areas of the brain that control our thinking, memory, and body movement.

Some people can have mixed dementia, where they are affected by two different diseases at the same time. Someone may be diagnosed as having dementia with Lewy bodies and Alzheimer’s disease, or dementia with Lewy bodies and vascular dementia. This means they will be affected by symptoms of both types of dementia.

DLB, Parkinson’s disease and Parkinson’s disease dementia

Dementia with Lewy bodies is closely related to Parkinson’s disease, but they are different conditions. The build-up of Lewy bodies is also found in Parkinson’s, and leads to symptoms like movement problems and tremors.

People who have Parkinson’s disease are more likely to go on to develop dementia. This is known as Parkinson’s disease dementia (PDD).

Dementia with Lewy bodies and Parkinson’s disease dementia can affect people in very similar ways. If memory problems and dementia symptoms appear before or at the same time as movement problems and symptoms, then a diagnosis of DLB is likely to be given. If Parkinson’s movement problems are experienced for a year or more before memory and thinking symptoms appear, a diagnosis of PDD is likely to be given.

It is not always easy to tell if a person has DLB or PDD, as the timing of the onset of memory and thinking problems is not always clear.

Lewy Body Dementia is an umbrella term that includes both DLB and PDD and can be useful in these situations. It can also be useful to group these conditions as there are many similarities, both in symptoms and in the needs of people with the conditions and their families.

For more information about Parkinson’s disease you can get in touch with Parkinson’s UK www.parkinsons.org.uk or 0808 800 0303

Dementia with Lewy bodies

Information in this booklet is for anyone who wants to know more about dementia with Lewy bodies (DLB). This includes people living with DLB, their carers, families and friends.

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This information was updated in December 2021 and is due to be reviewed in December 2023, it was written by Alzheimer’s Research UK’s Information Services team with input from lay and expert reviewers. Please get in touch if you’d like a version with references or in a different format.

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