What Is Lewy Body Dementia?

Lewy body dementia (LBD) is an age-related neurodegenerative disorder that causes a gradual cognitive decline. This decline in mental processing can severely impact your normal life and daily activities, more so as the condition progresses.

Lewy body dementia accounts for 15% of all cases of dementia.1 This article examines Lewy body dementia in more detail, looking at causes, symptoms, management, and diagnosis. 


Lewy body dementia (LBD) is a progressive neurodegenerative disorder characterised by the presence of abnormal protein deposits, called Lewy bodies, in the brain. These Lewy bodies disrupt the normal functioning of brain cells, leading to a decline in cognitive abilities and motor control.

Lewy body dementia encompasses two main clinical subtypes: dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). DLB is characterised by cognitive impairments, visual hallucinations, fluctuations in alertness and attention, and parkinsonism (a collection of motor symptoms that include rigidity, bradykinesia, and tremors). PDD, on the other hand, refers to the development of dementia in individuals who have previously been diagnosed with Parkinson's disease.

Causes of lewy body dementia

Lewy body dementia is caused by clumps of protein, called alpha-synuclein, aggregating inside brain cells. Alpha-synuclein plays a key role in facilitating communication between neurons in the brain. The clumps of protein are called Lewy bodies. These deposits build up in regions of the brain that are responsible for functions such as movement, thinking and visual perception. People with Parkinson’s disease may also develop Lewy body deposits. 

Signs and symptoms of lewy body dementia

The symptoms of Lewy body dementia can vary from person to person and may overlap with other neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease.

  • Apathy: This is where you experience a lack of motivation, interest or concern at a given moment 
  • Cognitive problems: This could include confusion, poor attention, visual-spatial problems and memory loss 
  • Depression
  • Parkinsonism: This is a movement disorder and is reported to occur in 85% of cases of Lewy body dementia.2 This includes slowed movement, rigid muscles, tremors or a shuffling walk. This is usually associated with an increased risk of falls
  • Poor regulation of body functions: Lewy body dementia can affect the autonomic nervous system. This system controls blood pressure, heart rate, sweating and digestion. Dysfunction in the autonomic nervous system may cause sudden drops in blood pressure upon standing, dizziness, falls, incontinence and constipation
  • Trouble with sleep: Many people with Lewy body dementia have rapid eye movement (REM) sleep disorder. This disorder is characterised by dream enactment behaviour. People with REM sleep disorder may punch and kick the air, yell, or scream while sleeping. This symptom is fairly common, with 76% of individuals living with Lewy body dementia exhibiting these signs 2
  • Varying attention: Episodes similar to that of delirium, where the person experiences episodes of drowsiness, long periods of staring into space, fatigue or incoherent speech
  • Visual hallucinations: Visual hallucinations are when you see things that are not there. Recurrent or frequent visual hallucinations are common in people with Lewy body dementia, occurring in about 80% of patients.2 These visual hallucinations are often a key signpost to diagnosing Lewy body dementia

Diagnosis of Lewy body dementia

Diagnosis can be challenging due to the similarity of symptoms with other neurological conditions.3 For this reason, a thorough medical evaluation, which includes taking a patient’s medical history, performing a neurological examination, and conducting cognitive assessments, is typically needed in order to make a diagnosis.

An initial assessment of global impairment is usually conducted. This typically involves the use of dementia screening tools, such as the Mini Mental State Examination (MMSE) or the Montreal Cognitive Assessment. 

Brain scans, such as an MRI or a CT scan, are used to help with diagnosis or the ruling out other causes. A SPECT scan can help to show changes in the brain that are more common in Lewy body dementia. 

Management and treatment for lewy body dementia

Although there is currently no cure for Lewy body dementia, treatment focuses on managing symptoms and improving the individual's quality of life. This may involve prescribing medications that can alleviate cognitive and psychiatric symptoms, directing a patient to physical therapy to address motor impairments, and referring to supportive care to manage day-to-day challenges. It is important for individuals living with Lewy body dementia, and their caregivers, to receive comprehensive support and education about the condition to cope with its effects.

Risk factors

  • Age: Those older than the age of 60 are at greater risk of developing Lewy body dementia
  • Sex: People assigned male at birth are more likely to develop Lewy body dementia than people assigned female at birth4
  • Family history: Those with a family history of Lewy body dementia or Parkinson’s disease have a greater chance of developing dementia themselves


Due to the progressive nature of the condition, the symptoms and features will get worse as time goes on. These can pose challenges to you and your family. Possible complications include:

  • Aggressive behaviour
  • Death within 5 to 7 years of diagnosis
  • Depression
  • Increased risk of falls and injuries
  • Severe dementia
  • Worsening of Parkinson-like symptoms, such as tremors


How can I prevent lewy body dementia?

The exact cause of Lewy body dementia is not fully understood, but it is believed to involve a combination of genetic, environmental, and lifestyle factors. Research suggests that there may be a link between Lewy body dementia and abnormalities in the brain's processing of alpha-synuclein protein, which forms the main component of Lewy bodies. Whilst there is nothing you can do to specifically prevent getting Lewy body dementia, you can live a healthy lifestyle in order to reduce your risk. Maintaining a healthy weight, keeping your brain occupied with cognitively challenging activities, eating a balanced diet, and exercising will all optimise your physical and mental health and may reduce the risk of you developing dementia. 

How common is lewy body dementia?

In the general population, Lewy body dementia is rare, with a prevalence of 3.5 out of every 100,000 people. The incidence of this condition increases steeply with age. Those assigned male at birth have a higher incidence of Lewy body dementia than those assigned female at birth.4 In the population of people with dementia, the prevalence of Lewy body dementia is 15%.1

What can I expect if I have lewy body dementia?

Lewy body dementia is a neurodegenerative disorder with no known cause. There will be a gradual decline in cognitive function and motor abilities. Home-based care will usually be needed and eventually, a care home is needed for some. The average survival time after diagnosis is usually between 5 and 7 years. However, this does differ from person to person. The speed of cognitive decline will also be different for each individual.

If you, or someone close to you, has been diagnosed with Lewy body dementia, there are services available for support. Speak to your doctor or specialist dementia team for advice on what support is available to you.

When should I see a doctor?

It is important to see a doctor if you experience a major or sudden change in cognitive function and behaviour. The most common symptoms to look out for are changes in behaviour, cognition, movement and sleep. 


Lewy body dementia is a common type of dementia that presents with a complex range of symptoms that are not only shared with other similar conditions but also pose a challenge in the management of the condition. Symptoms such as visual hallucinations, cognitive difficulties, depression, Parkinsonian symptoms, and sleep problems can be very distressing for the individual and those close to them. There is currently no cure for Lewy body dementia. It progressively gets worse as time goes on, accelerating more rapidly in the later stages. Treatment and management consists primarily of managing the symptoms with medication and therapy in order to reduce levels of distress, but this becomes harder as time goes on. There are a variety of support services, ranging from specialist dementia services to charity groups, that offer support and activities for those with Lewy body dementia and those close to them. 


  1. Walker Z, McKeith I, Rodda J, Qassem T, Tatsch K, Booij J, et al. Comparison of cognitive decline between dementia with Lewy bodies and Alzheimer’s disease: a cohort study. BMJ Open [Internet]. 2012 Jan 1 [cited 2023 Jul 13];2(1):e000380. Available from: https://bmjopen.bmj.com/content/2/1/e000380
  2. McKeith IG, Boeve BF, Dickson DW, Halliday G, Taylor JP, Weintraub D, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. Neurology [Internet]. 2017 Jul 4 [cited 2023 Jul 13];89(1):88–100. Available from: https://n.neurology.org/content/89/1/88
  3. Morra LF, Donovick PJ. Clinical presentation and differential diagnosis of dementia with Lewy bodies: a review. Int J Geriatr Psychiatry. 2014 Jun;29(6):569–76. https://pubmed.ncbi.nlm.nih.gov/24150834/
  4. Savica R, Grossardt BR, Bower JH, Boeve BF, Ahlskog JE, Rocca WA. Incidence of dementia with lewy bodies and parkinson disease dementia. JAMA Neurology [Internet]. 2013 Nov 1 [cited 2023 Jul 13];70(11):1396–402. Available from: https://doi.org/10.1001/jamaneurol.2013.3579 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Karl Jones

BA Hons in Learning Disability Nursing, Diploma in Mental Health Nursing (Oxford Brookes

Karl has 12 years of experience in learning disability and mental health nursing in a variety of
settings. He has worked predominantly in general hospitals specialising in suicide prevention and the
psychological impact on long term health conditions. Most recently he has worked as a clinical
educator in the field of mental health. He is currently focusing on writing as a career with the aim of
imparting his knowledge to a wider audience.

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