Lewy body dementia (LBD) covers two types of dementia: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD).

Lewy body dementia is a progressive condition, thought to account for approximately 15% of cases of dementia. It is more common in people over the age of 65 but also accounts for around 10% of cases of early-onset dementia, where symptoms begin before 65.

In the early stages, Lewy body dementia is often mistaken for – and misdiagnosed as –   Alzheimer’s disease. 

REM sleep issues, difficulties with movement (Parkinsonism), hallucinations, confusion about the identity of familiar people, and problems of the autonomic nervous system – blood pressure dropping on standing, dizziness, falls and urinary incontinence, are all more common in early Lewy body dementia.

Memory loss tends to be the major symptom in early Alzheimer’s.

Not everyone with Parkinson’s will develop dementia, but the risk increases the longer someone lives with the condition.

Lewy bodies are present in brains of people with Parkinson’s, usually in the areas responsible for movement.

The main difference between the two types of Lewy body dementia is when certain symptoms first occur.                                                        

In dementia with Lewy bodies (DLB), cognitive changes happen first. These include:

• changes in thinking
• difficulties with visual perception (eg spatial awareness, misinterpreting visual information)
• memory loss
• managing everyday tasks
• staying alert

These tend to occur at least one year before, or at the same time as, the person develops problems with movement.                                                                 

In Parkinson’s dementia (PDD), physical changes happen first. This includes difficulties with movement (Parkinsonism), such as tremors, rigidity or slowness.

These symptoms are experienced one year or more before the cognitive changes.

Lewy body dementia is caused by abnormal clumps of protein – Lewy bodies – gathering inside brain cells. These can build up in many parts of the brain but particularly in the areas responsible for thought, movement, visual perception, sleep and alertness.

Lewy bodies are abnormal clumps of protein inside brain cells. They were discovered by Dr Friedrich Lewy in 1912. Lewy bodies are associated with the death of brain cells and deterioration of brain function. A major constituent of Lewy bodies is an altered protein called alpha-synuclein and that is why some people refer to diseases such as Lewy body dementia and Parkinson’s as alpha-synucleinopathies.

Men are more at risk than women. Lewy body dementia most often develops between ages 50 and 85.

Dementia with Lewy bodies usually occurs in people with no family history of the condition, although there have been very rare cases where is has seemed to have been hereditary.

On average, people tend to live five to seven years after diagnosis, however it is possible to live much longer

Thank you for asking! We rely entirely on donations to fund our work raising awareness and supporting research into Lewy body dementia. You can see some of the great projects we support here  and this is our donation page. We also encourage our supporters to volunteer for studies themselves with Join Dementia Research  – Lewy body dementia is notable underrepresented. And of course, get involved in Dotty Days, our Lewy body dementia awareness week at the end of June.