Dementia with Lewy bodies

Expert reviewer Dr Rahul Bhattacharya, Consultant Psychiatrist
Next review due April 2022

Dementia with Lewy bodies is a condition that affects the brain. It is the third most common type of dementia, which is a term used to describe a set of symptoms, including problems with memory and thinking. Dementia with Lewy bodies can have some similarities with Parkinson's disease.

Symptoms of dementia with Lewy bodies

Some symptoms of dementia with Lewy bodies are similar to other types of dementia, such as Alzheimer's disease. These dementia signs can include difficulty managing and memory loss, which may come on later in the course of the disease. But the condition also has some quite specific symptoms:

• fluctuations in mental ability, concentration and alertness
• seeing things – visual hallucinations happen in up to eight out of 10 people
• physical symptoms similar to those of Parkinson’s disease will come on at some point in up to nine out of 10 people

Doctors will look for these symptoms as part of their assessments for diagnosing dementia.

Mental state

The brain’s function tends to get worse over time in dementia with Lewy bodies. As it worsens the person will become less able to look after themselves and need more and more help.

A particular early symptom of dementia with Lewy bodies is a fluctuation in mental ability, attention and level of alertness. This can cause someone to be silent and unresponsive for several minutes at a time. People sometimes describe this as ‘zoning out’.

Around eight out of 10 people with dementia with Lewy bodies see things that are not there (have hallucinations). About one in five hear things that are not there. These are called auditory hallucinations.

Hallucinations may happen at night, making them difficult to distinguish from dreams. This is made more difficult to cope with by another symptom called rapid eye movement (REM) sleep disturbance. This causes vivid dreams, meaning someone may call out and act out their dreams in their sleep.

Depression can occur in around four out of every 10 people diagnosed with dementia with Lewy bodies. They may also have anxiety.

Parkinson’s disease symptoms

Some of the symptoms of dementia with Lewy bodies are similar to those of Parkinson's disease. These symptoms gradually worsen over a number of years.

People may:

• move very slowly and develop a very particular way of walking in a shuffling way, taking very small steps while leaning forwards
• have an expressionless face (people sometimes describe this as ‘mask-like’)

One common Parkinson’s disease symptom that people with dementia with Lewy bodies don’t generally have is shaking (tremor), but it can sometimes occur.

How dementia with Lewy bodies develops

Dementia with Lewy bodies is a long-term condition that gets worse over time, and it generally develops quite gradually. On average, people live for between five and eight years after diagnosis.

In dementia with Lewy bodies, hallucinations can be one of the first signs that something is wrong. The varying mental state and attention span are also often early signs of the disease.

Memory problems may not show up straightaway but can become a problem later in the course of the disease. Parkinson’s symptoms can develop early in the disease in some people, but later in others.

As the condition develops, the person with dementia will have more difficulty managing day-to-day life. They’re likely to need help with basic daily tasks, such as washing and dressing. As the condition gets progressively worse, many people eventually need to be looked after full time, which is often only possible in residential care.

As with many long-term illnesses, dementia with Lewy bodies can have complications. People are more likely to have frequent falls than with other types of dementia. This is due to the Parkinson’s symptoms that they have. These also cause difficulty swallowing, which means that people with dementia with Lewy bodies are at risk of inhaling food or drinks. This increases their risk of pneumonia.

Causes of dementia with Lewy bodies

Doctors don’t fully understand what causes dementia with Lewy bodies. Brain cells taken from people after they have died show the same typical clumps of protein (Lewy bodies) that form inside nerve cells in Parkinson’s disease. Doctors think that these are toxic to brain cells.

Other theories about the causes of dementia with Lewy bodies are that a key chemical process in cells gets interrupted and brain cells are then unable to work properly. Or the cells may be affected by other abnormal processes such as inflammation. A few changes in genes have been found in families where dementia with Lewy bodies is more common. But most cases of dementia with Lewy bodies do not run in families and it is not clear how important these changes in genes are generally.

Treatment for dementia with Lewy bodies

Unfortunately, there is no cure for dementia with Lewy bodies as yet. However, a number of different medicines can be prescribed to treat it. There are other steps that loved ones can take at home, and therapies such as counselling, that can help to improve life for someone with dementia with Lewy bodies.

Medicines

At first, your doctor is likely to suggest one of two medicines:

• donepezil (Aricept)
• rivastigmine (Exelon)

The names in brackets are the brand names. These are both the same type of drug, called acetylcholinesterase inhibitors. They may help with hallucinations, delusions and agitation, which are common symptoms of dementia with Lewy bodies. Rivastigmine may also help people to sleep better.

All these medicines have to be prescribed by a specialist and are either tablets or capsules. Rivastigmine also comes as a stick-on patch that can be easier for some families to manage than tablets. You may find it helpful to download our medicines planner for dementia carers (PDF, 0.8MB).

When someone has delusions and hallucinations, a doctor would usually prescribe medicines called anti-psychotics. However, they don’t generally prescribe these for someone with dementia with Lewy bodies as they can make Parkinson’s disease symptoms worse. They may also make the person’s dementia and their physical health considerably worse. Around half of those with dementia with Lewy bodies have severe adverse reactions to anti-psychotics. So, doctors may prescribe acetylcholinesterase inhibitors instead.

Other medicines used in dementia with Lewy bodies

Sometimes people with dementia with Lewy bodies can be very anxious and agitated. If this is the case, the doctor may prescribe a medicine for anxiety, such as lorazepam. This will only be for a short time, as these medicines can make memory problems worse. As around four out of 10 people with dementia with Lewy bodies have depression, doctors often prescribe anti-depressants.

Many people have disturbed sleep and this can be treated with a medicine called clonazepam. It is helpful in nine out of 10 people with dementia with Lewy bodies.

Other therapies for dementia with Lewy bodies

There are several other ways that life can be improved for people with dementia. Keeping active and doing as much as possible for themselves can help people to sleep better, stay mobile and look after themselves for longer. Similarly, mental activity and interacting with others can help to maintain memory and social skills. Physiotherapy and occupational therapy may help to prevent falls.

At earlier stages, talking therapies enable people with dementia to share their feelings and can help with anxiety and depression. Complementary therapies can aid relaxation and in later stages of dementia help with management of difficult symptoms such as agitation. There isn’t a great deal of research evidence about the benefits of these kinds of therapies for people with dementia, but some people do find that they help.