Lewy body dementia, also called dementia with Lewy bodies, is one of the common types of dementia. It is linked to clumps of a protein called alpha-synuclein inside brain cells, the same protein involved in Parkinson’s disease. The first changes may not be memory loss. They can include swings in alertness, seeing things that are not there, slow or stiff movement, falls and acting out dreams. If you notice changes like these, start with the GP.
The type matters. People with Lewy body dementia can be very sensitive to antipsychotic medicines, which can make movement worse and sometimes cause a severe reaction. This guide sets out what is different about it, how diagnosis works and what helps keep people safe at home.
How many types of dementia are there?
Dementia is not one disease. It is the name for a group of symptoms caused by different diseases that damage the brain, so there is no fixed number of types. The main ones:
Alzheimer’s disease is the most common type in the UK.
Vascular dementia, caused by reduced blood flow to the brain, is the second most common.
Dementia with Lewy bodies is another of the common types.
Frontotemporal dementia is less common overall, but makes up a larger share of dementia in younger people.
Mixed dementia means more than one type at once, most often Alzheimer’s and vascular dementia together.
People with Parkinson’s disease can also go on to develop dementia, and there are a number of rarer causes.
Estimates of how common it is vary by source and method. Alzheimer’s Society puts it at about 1 in 10 people with dementia, but only around 5% of recorded diagnoses name it. Dementia UK gives 10 to 15% of diagnoses. Both cite studies suggesting it may be up to 20%. It can be mistaken for Alzheimer’s disease or, after an emergency admission, for delirium. Delirium and dementia can also happen at the same time.
The first signs of Lewy body dementia
The general early signs of dementia include memory loss, trouble concentrating, struggling with familiar tasks or finding the right word, confusion about time and place, and mood changes. Lewy body dementia can share many of them. Memory may be less affected early on, though some people do notice memory problems from the start. What may stand out:
Good hours and bad hours. Alertness and confusion can swing unexpectedly, over minutes or hours. Someone may stare into space or sleep much of the day, then be much clearer later the same day.
Seeing things that are not there. Visual hallucinations are common and can range from pleasant to distressing.
Movement changes like Parkinson’s. Slow movement, stiff limbs, a tremor or shuffling when walking. In Lewy body dementia, thinking problems usually start before or around the same time as the movement problems.
Falls and fainting. Unsteadiness, fainting spells and falls.
Restless nights. Talking in sleep and acting out dreams, sometimes with violent movement or shouting, and sleepiness in the day.
None of these alone means dementia, and many have other causes, which is why the GP is the first step.
How diagnosis works
There is no single test. The GP usually starts by asking about symptoms and everyday tasks and examining the person. They may use a short memory test and blood or urine tests to look for other causes, such as an infection, and review medicines for side effects. A normal score on a memory test does not on its own rule dementia out. It helps if someone who knows the person well goes too.
If other causes have been looked at and dementia is still suspected, the GP usually refers the person to a memory service. Other clinicians can refer too.
In Ealing and Hounslow, that is West London NHS Trust’s Cognitive Impairment and Dementia Service. In Hillingdon, Harrow and Brent, it is the memory service run by Central and North West London NHS Foundation Trust: Hillingdon, Harrow or Brent.
Specialists may arrange a CT or MRI scan where it is needed. If Lewy body dementia is suspected, the diagnosis is still uncertain and the answer could change care, NICE recommends a specialised brain scan called FP-CIT SPECT. If that is not available, the specialist may consider a heart scan that shows how well the nerves supplying the heart are working. A normal result does not on its own rule Lewy body dementia out, and the specialist decides which tests are right.
One practical point: a test done on a good day can miss symptoms. A simple diary of good and bad hours, falls and disturbed nights gives the doctor what one appointment cannot.
Five safety points every family should know
1Say “Lewy bodies”, not just “dementia”
For anyone with dementia, NICE says antipsychotic medicines should only be offered after assessment, when a person is at risk of harm or severely distressed. In Lewy body dementia they carry an extra risk: they can make movement worse and sometimes cause a severe reaction. Make sure any new doctor, hospital ward and pharmacist knows the diagnosis and that it is recorded in the notes. Decisions about medicines stay with the prescriber.
2Expect fluctuation, but know an emergency
Good and bad hours are part of the condition. Sudden new or markedly worse confusion is different. The NHS says go to A&E or call 999. It can be delirium, which can happen alongside dementia.
3Don’t argue with what they see
Trying to convince someone a hallucination is not real rarely helps. Reassure them, stay with them and gently distract. Keep glasses clean and hearing aids working. Tell the GP or memory service about hallucinations that are new, frequent or distressing.
4Plan for falls and fainting
Good lighting, clear floors and no trip hazards help. Strength and balance exercises suited to the person, an eyesight test or a medicine review may reduce the risk. Frequent falls or fainting need a check by the GP, who can refer to a falls service.
5Make the bed area safe
Because people may act out their dreams, Alzheimer’s Society suggests removing sharp objects from beside the bed. For some people, a mattress on the floor alongside it helps, and some partners choose separate beds. Talk changes through with the GP or an occupational therapist so they suit the person and leave a clear route to the door and toilet.
There is no cure and no treatment known to slow Lewy body dementia, but some symptoms can be helped. NICE recommends donepezil or rivastigmine for mild to moderate Lewy body dementia, and they may help with hallucinations, confusion or sleepiness in some people. The prescriber weighs the benefits and side effects and decides any change. For urgent advice out of hours, call NHS 111.
What helps at home, and what a home care team adds
A routine, staying active, music and time with other people can all help. Pain, constipation, dehydration or an infection can make someone more confused. If you notice any of these, tell the GP or pharmacist. If confusion comes on suddenly or is much worse, go to A&E or call 999.
Dementia training is worth asking about. In the unweighted Skills for Care data used in CQC’s State of Care report, published on 23 October, 38% of staff providing direct care had a completed dementia training course recorded. That figure describes the dataset, not any one carer, so ask the provider what training the carer who will visit has had.
At Marigold, our carers are trained specifically to support people living with dementia, including Alzheimer’s disease, vascular dementia and Lewy body dementia.
In practice, the care plan aims for visits at regular times and the same calm greeting, built around the person’s routine. Carers meet confusion with patience rather than rushing, arguing or correcting. We place the same carers with each person wherever possible so routines and faces stay familiar.
If your relative is coming home from hospital, or their needs have changed, say so on the first call so we can tell you honestly how fast we can start. For sudden new or much worse confusion, contact the NHS first: A&E or 999.
“With Lewy body dementia, the good hours and the hard hours can sit in the same morning. What we can keep steady is everything around them: the same faces, the same time, the same calm hello.”
Marigold Home CareWhat to ask any home care provider
Has the carer who will visit completed dementia training that covers Lewy body dementia? Will the same carers come each week? What do carers do if confusion suddenly gets worse? Does the care plan say Lewy body dementia, not just dementia? A provider who answers plainly is worth a second conversation.
Questions families ask
Is Lewy body dementia the same as Parkinson’s?
No, but they are related. Both involve Lewy bodies, clumps of the protein alpha-synuclein, and both can cause movement problems. In dementia with Lewy bodies, thinking problems usually start before, or within about a year of, the movement symptoms. In Parkinson’s disease, dementia, if it comes, develops after the movement symptoms are well established, often years later. A specialist makes the distinction from the full history.
Why does Mum seem fine one day and confused the next?
Swings in alertness are one of the hallmarks of Lewy body dementia and can change over minutes or hours. Note the pattern for the GP. If there is sudden new or markedly worse confusion, the NHS says go to A&E or call 999, because it can be delirium.
Is there a cure for Lewy body dementia?
Not yet, and no treatment is known to slow it down. Medicines, physiotherapy, occupational therapy, speech and language therapy and activities can help with symptoms. For some people, symptoms may be helped for several years.
What should I take to a memory clinic appointment?
Take a list of current medicines, and a short diary of good and bad hours, falls, fainting and disturbed nights. Bring someone who knows the person well, and write down your questions beforehand.
What should I tell hospital staff?
Say “dementia with Lewy bodies”, not just “dementia”, and ask for it to be recorded in the notes so it is considered before any medicines are given. Describe what the person is usually like, so staff can spot sudden changes.
Facts in this guide were checked against the sources below on 12 November 2026. This is general information, not advice for any one person. Diagnosis and medicines are for the GP, memory service, specialist and prescriber. In an emergency, call 999.
Worried about good days and bad days?
Tell us how things are at home. A free home assessment sets out what dementia care would look like, from £21.96 an hour. We call back the same working day, and the visit is usually within 24 hours.
Book a Free Assessment