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Overview - Dementia with Lewy bodies

Dementia is caused by different diseases of the brain. Dementia with Lewy bodies (DLB), also known as Lewy body dementia, is one of the most common types of dementia. 

It develops slowly and gets gradually worse over several years.

Symptoms of dementia with Lewy bodies

People with dementia with Lewy bodies may have:

  • hallucinations – seeing, hearing or smelling things that are not there
  • problems with understanding, thinking, memory and judgement – this is similar to Alzheimer's disease, although memory may be less affected in people with dementia with Lewy bodies
  • confusion or sleepiness – this can change over minutes or hours
  • slow movement, stiff limbs and tremors (uncontrollable shaking)
  • disturbed sleep, often with violent movements and shouting out
  • fainting spells, unsteadiness and falls

These problems can make daily activities increasingly difficult. Someone with the condition may eventually be unable to look after themselves.

Read more about the symptoms of dementia with Lewy bodies

When to see your GP

See your GP if you think you have early symptoms of dementia, especially if you're over 65.

If you're worried about someone else, encourage them to see their GP. You could suggest that you go with them.

The GP can do some simple checks to try to find the cause of your symptoms. They will refer you to a memory clinic or another specialist for further tests if needed.

Causes of dementia with Lewy bodies

Dementia with Lewy bodies is caused by clumps of protein forming inside brain cells. These abnormal deposits are called Lewy bodies.

These deposits are also found in people with Parkinson's disease. They build up in areas of the brain that affect thinking, visual perception and muscle movement.

It's not clear why the deposits develop and how exactly they damage the brain. It may be that the proteins affecting the brain's normal functions interfere with signals sent between brain cells.

Dementia with Lewy bodies usually happens in people with no family history of the condition. There have been rare cases that seem to run in families.

Tests for dementia with Lewy bodies

There is no single test for dementia with Lewy bodies.

The tests that are needed to make a diagnosis include:

  • an assessment of symptoms
  • an assessment of mental abilities – this will usually involve some tasks and questions
  • blood tests to rule out conditions with similar symptoms
  • brain scans, such as an MRI scan, CT scan or a SPECT scan - these can detect signs of dementia or other problems with the brain

Treatments for dementia with Lewy bodies

There is currently no cure for dementia with Lewy bodies or any treatment that will slow it down.

There are treatments that can help control some of the symptoms.

Treatments include:

  • medicines to reduce hallucinations, confusion, drowsiness, movement problems and disturbed sleep
  • therapies such as physiotherapy, occupational therapy and speech and language therapy
  • psychological therapies designed to improve memory, problem-solving skills and language
  • dementia activities, such as dementia cafes for people and carers to get support and advice

Read more about treatment for dementia with Lewy bodies

Outlook for dementia with Lewy bodies

How quickly dementia with Lewy bodies gets worse varies from person to person.

Most people will need home-based help. Some people will eventually need care in a nursing home.

The average survival time after diagnosis is around 6 to 12 years. But this varies and some people live much longer than this.


If you or a loved one has been diagnosed with dementia, remember that you're not alone.

Dementia Understand Together

This is a dementia awareness campaign run by the HSE. It offers a list of local supports across Ireland.

Find supports and services in your area -

The Alzheimer Society of Ireland

The Alzheimer Society of Ireland has advice and support for you and your family.

Content supplied by the NHS and adapted for Ireland by the HSE

Slaintecare logo
This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 26 August 2021
Next review due: 26 August 2024