Lewy Body Dementia

Lewy body dementia (LBD) is a common type of dementia that happens when clumps of proteins called Lewy bodies build up in your brain. They damage parts of your brain that affect cognition, behavior, movement and sleep. LBD is a progressive condition, meaning it gets worse over time. There’s no cure, but medications and therapies can help manage symptoms.


Lewy body dementia symptoms: movement problems, changing cognition, sleep issues, mood swings, and dysautonomia.
Lewy body dementia (LBD) symptoms may resemble those of other neurological disorders, like Alzheimer’s disease. They fluctuate over time and vary from person to person.

What is Lewy body dementia?

Lewy body dementia (LBD) is a type of dementia in which Lewy bodies are present in your brain. Lewy bodies are clumps of proteins that build up inside certain neurons (brain cells). They cause damage to neurons in the areas of your brain that affect mental capabilities, behavior, movement and sleep.

Lewy body dementia is a progressive disease, meaning symptoms start slowly and get worse over time.

In people over the age of 65, LBD is one of the most common causes of dementia. The symptoms of LBD may closely resemble those of other neurological conditions, including Alzheimer’s disease and Parkinson’s disease.

There’s no cure for LBD, but the symptoms can be managed with certain medications. You or your loved one may also benefit from nonmedical treatments like physical therapy and speech therapy.


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How is Lewy body dementia related to Alzheimer’s disease and Parkinson’s disease?

Dementia with Lewy bodies and Parkinson’s disease dementia are two related clinical disorders that make up the general broader category of Lewy body dementia. Sometimes, providers first diagnose LBD as Parkinson’s disease or Alzheimer’s disease based on its symptoms.

  • Parkinson’s disease dementia (PDD): Some people are diagnosed with Parkinson’s disease if they first have symptoms of a movement disorder typical to Parkinson’s. But their diagnosis is changed to PDD if dementia symptoms develop over the years.
  • Alzheimer’s disease (AD): Some people who have a memory or cognitive disorder are diagnosed with AD. But other distinctive symptoms may suggest co-existing dementia with Lewy bodies. Distinctive symptoms of LBD include changes in attention, alertness and cognitive ability; movement issues; visual hallucinations; and more.

Who does Lewy body dementia affect?

Lewy body dementia (LBD) typically affects people over the age of 50. The older you are, the more at risk you are for developing the condition. Men and people assigned male at birth are more likely to have Lewy body dementia than women and people assigned female at birth.

A family history of LBD and Parkinson’s disease also increases your risk of developing it.


How common is Lewy body dementia?

Lewy body dementia is one of the most common types of progressive dementia. Researchers estimate that as many as 1.4 million people live with this condition in the United States.

Symptoms and Causes

What are the symptoms of Lewy body dementia?

Lewy body dementia (LBD) symptoms may resemble those of other neurological disorders, like Alzheimer’s disease and Parkinson’s disease. Symptoms fluctuate over time and vary from person to person.

There are several possible symptoms of LBD, which can be grouped into the following categories:

  • Movement issues.
  • Cognitive symptoms.
  • Sleep problems.
  • Dysautonomia.
  • Mood and behavior changes.

Movement symptoms of Lewy body dementia

One of the core features of LBD is parkinsonism, which is an umbrella term that refers to brain conditions that cause movement issues including:

  • Slowed movements (bradykinesia).
  • Rigidity or stiffness.
  • Tremors.

Some people with LBD may not experience significant movement issues for several years, while others may experience them early on. At first, movement symptoms may be very subtle and easy to miss.

Other movement symptoms of LBD include:

Cognitive symptoms of Lewy body dementia

Fluctuating cognitive (mental) function is a relatively specific feature of Lewy body dementia. A person with LBD may experience periods of being alert and coherent in between periods of being confused and unresponsive to questions. This can change from day to day or within the same day.

Other cognitive symptoms include a decline in:

  • Planning abilities.
  • Problem-solving skills.
  • Decision-making
  • Memory (Unlike in Alzheimer's dementia, memory problems may not be present at first but often arise as LBD progresses).
  • Ability to focus.
  • Understanding information in visual form.

Visual hallucinations, or seeing things that aren’t there occur in up to 80% of people with LBD and often early on in the condition. Other types of hallucinations, such as hearing or smelling things that aren’t there, are less common than visual ones but may also occur.

Visuospatial difficulties, including decreased depth perception, trouble recognizing familiar objects and impaired hand-eye coordination, are also common in people with LBD.

Sleeping problems in Lewy body dementia

Sleep disorders are common in people with LBD, especially rapid eye movement (REM) sleep behavior disorder (RBD). This condition involves frequent movements, such as flailing or punching, with yelling or speaking while sleeping. People living with RBD often have difficulty separating dreams from reality when they wake up.

Other sleep issues associated with LBD include:

  • Excessive daytime drowsiness.
  • Changes in sleep patterns.
  • Insomnia.

Dysautonomia in Lewy body dementia

Dysautonomia is a general term for a group of disorders that share a common problem — that is, an autonomic nervous system (ANS) that doesn’t function as it should.

The ANS is the part of your nervous system that controls involuntary body functions (functions you don’t consciously control) like your heart rate, blood pressure, breathing, digestion and many more.

People with LBD can experience issues with their autonomic nervous system, which may result in the following symptoms:


Mood and behavioral symptoms of Lewy body dementia

People with LBD may experience behavior and mood changes, which may worsen as their thinking abilities decline. Symptoms may include:

  • Depression.
  • Anxiety.
  • Agitation, restlessness or aggression.
  • Delusions (strongly held false beliefs or opinions that have no basis in reality).
  • Paranoia (an extreme, irrational distrust of others).

What causes Lewy body dementia?

A buildup of Lewy bodies (proteins called alpha-synuclein) causes both dementia with Lewy bodies and Parkinson’s disease dementia. When Lewy bodies build up in neurons, they cause damage to certain areas of your brain.

Researchers don’t know why some people develop LBD while others don’t. There’s some thought that the combination of mutations in a person’s genes, environmental risk factors and natural aging might lead to the development of LBD in some people. Research into specific causes is ongoing.

One of the more recent discoveries toward identifying a cause of Lewy body dementia is the finding of an increasing number of gene mutations. Two genetic risk factors recently discovered are variants in the APOE and GBA genes.

APOE is already known to increase the risk of developing Alzheimer’s disease. There’s growing evidence that it also increases the risk for dementia with Lewy bodies. Similarly, the GBA gene increases the risk for both Parkinson’s disease and dementia with Lewy bodies. Despite these findings, genetic changes as a cause of LBD are still considered rare by scientists. Most cases of Lewy body dementia aren’t thought to be inherited (passed down from parent to child).

Diagnosis and Tests

How is Lewy body dementia diagnosed?

Diagnosing Lewy body dementia (LBD) can be challenging. Early LBD symptoms are often confused with symptoms found in other brain or psychiatric conditions.

There are no medical tests that can diagnose Lewy body dementia with 100% accuracy. A diagnosis may require a group of specialists, including:

Together, they can make the diagnosis of “probable LBD” based on the combined results of tests and symptoms.

Along with a history of progressive cognitive decline that interferes with daily activities, a diagnosis of LBD is considered probable if two of the following four core features are present and is considered possible if only one is present:

Some people with Parkinson’s disease who develop cognitive symptoms less than a year after the onset of movement problems may be diagnosed with Lewy body dementia.

Healthcare providers use the following strategies to help diagnose LBD and to rule out conditions that cause similar symptoms:

  • Detailed medical history and physical examination: Your provider will ask about the history of your symptoms. Be sure to tell them of any physical, cognitive, memory, emotional, behavioral, movement, sleep or physical changes you’re having. They may also ask your family members and loved ones about your symptoms. Also, tell your provider about any of your current medications, supplements, vitamins, herbal products and frequently used over-the-counter products.
  • Imaging tests: Imaging tests, such as an MRI scan and CT scan, typically don’t help diagnose Lewy body dementia because the changes in your brain due to LBD often mimic those seen in people with vascular dementia. But they can help rule out other possible causes of your symptoms, such as bleeding in your brain or a tumor.
  • Neurological exam: This exam assesses your mental function. It checks thinking abilities, including memory, word-finding, attention and visual-spatial skills.
  • Blood tests: Your provider may order certain blood tests, such as thyroid blood tests, a test to check vitamin B12 levels and tests to check for conditions like syphilis and HIV. These tests can help rule out other causes of dementia.
  • Sleep studies: Your provider may recommend sleep studies to check for REM sleep behavior disorder. It involves sleeping in a lab overnight. During this test, sensors monitor your heart, brain activity, breathing patterns, arm and leg movements, vocalizations and more. You may also be recorded to document your behavior during REM sleep cycles.

Management and Treatment

How is Lewy body dementia treated?

There’s no cure for Lewy body dementia (LBD). Medications and nonmedical therapies, like physical, occupational and speech therapies, manage symptoms as much as possible.

Medications that can help manage the symptoms of LBD include:

  • Cholinesterase inhibitors: This type of medication, which includes rivastigmine, galantamine and donepezil, helps manage the cognitive symptoms of LBD.
  • Carbidopa-levodopa: Symptoms of parkinsonism, like tremors, are usually treated with levodopa, a drug commonly used to treat Parkinson’s disease. However, it has serious side effects and can lead to delusions, hallucinations and confusion.
  • Pimavanserin: This medication can be used to treat psychosis (hallucinations, delusions) in people with Parkinson’s disease dementia.
  • Clonazepam and melatonin: These medications can help treat REM sleep behavior disorder.
  • Antidepressants: Depression is common in people with LBD and often requires antidepressant therapy with selective serotonin reuptake inhibitors (SSRIs).
  • Memantine: This drug is typically used to treat dementia caused by Alzheimer’s disease, but it’s been investigated in clinical trials and may work in people with LBD who are in the early phases of the condition.

People with LBD can take part in different therapies to improve their quality of life, including:

  • Physiotherapy.
  • Occupational therapy.
  • Speech therapy.
  • Support groups.
  • Individual and family psychotherapies (talk therapies).
  • Exercise.

In advanced cases of Lewy body dementia, palliative care — care that provides symptom relief, comfort and support to people living with serious illnesses — may be more appropriate than highly aggressive medical interventions or hospital care.


Can Lewy body dementia be prevented?

Currently, there’s no known way to prevent Lewy body dementia (LBD).

Outlook / Prognosis

What is the prognosis (outlook) of Lewy body dementia?

The prognosis (outlook) of LBD is generally fair to poor because it gets worse over time.

People with LBD can die from several different complications, such as:

  • Falls.
  • Immobility.
  • Heart complications.
  • Medication side effects.
  • Pneumonia.
  • Swallowing issues.
  • Depression leading to suicide
  • Reactions to first-generation antipsychotic medications used to treat and manage symptoms of many psychiatric disorders, such as neuroleptic malignant syndrome.

If you or a loved one has been diagnosed with LBD, it’s important to learn about the condition and all the medications and therapies that can help you be as comfortable and safe as possible.

What can I expect if a loved one or I have Lewy body dementia?

Each person’s experience with Lewy body dementia (LBD) is unique to them. How slowly or quickly the disease progresses is impossible to know, but may be influenced by your general health and any existing conditions you may have.

Because LBD is a progressive disease, difficulties with mind and body functions get worse over time. Currently, there’s no known way to stop the progression of the disease.

However, there’s always hope. Research on dementia with Lewy bodies, Alzheimer’s disease and Parkinson’s disease with dementia are ongoing. New medications are being developed and new treatment approaches are being investigated.

What is the life expectancy for people with Lewy body dementia?

The average life expectancy of Lewy body dementia is five to eight years after the initial diagnosis. But some people with LBD live up to 20 years after their diagnosis.

This short average life expectancy could be due to a lack of knowledge regarding LBD among healthcare providers and the population and difficulty in distinguishing it from other similar conditions. This often leads to a delay in diagnosis, which delays the onset of specific therapy.

Living With

How do I take care of someone with Lewy body dementia?

If you care for someone who has been diagnosed with Lewy body dementia (LBD), it’s important to learn about the condition and seek professional guidance to help care for them at home. Understanding LBD can help you cope with everyday challenges.

You may need to make changes to your home to make everyday life easier for them. For example, it helps to have a bright, cheerful and familiar environment. It’s also important to make sure your home is safe and clear of any obstacles that could cause falls.

Your loved one’s healthcare team can help guide you with these changes.

As insight and judgment skills decline in people with LBD, you may need to appoint someone else to oversee their finances. Before their decline in mental function is severe, it’s also important to clarify their wishes about care and financial and legal arrangements.

When should I see my healthcare provider about Lewy body dementia?

If you or a loved one are experiencing symptoms of Lewy body dementia, talk to your healthcare provider.

If you’ve been diagnosed with Lewy body dementia, you’ll need to see your healthcare team regularly to monitor your health and symptoms and to make sure your medications are working.

A note from Cleveland Clinic

Learning early that you have a diagnosis of Lewy body dementia (LBD) allows you and your family to plan for a meaningful quality of life together and enables you to get your legal, financial and healthcare plans and desires in order. Your healthcare team will be ready to provide education, support and care for you or your loved one. Ask your team for information on local LBD support groups as well. Support groups can be very helpful for sharing care tips and providing comfort in knowing you’re not alone.

Medically Reviewed

Last reviewed on 08/18/2022.

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