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What Is Lewy Body Dementia?

What Is Lewy Body Dementia?
Everyday Health
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Updated on May 1, 2025
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Lewy body dementia is a type of dementia (cognitive impairment that interferes with daily activities) caused by deposits of a protein, called alpha-synuclein, in the brain. These deposits form clumps, called Lewy bodies, that doctors can see under a microscope. It’s likely the second most common type of dementia after Alzheimer’s disease.

The areas of the brain affected by Lewy body dementia are involved in thinking and memory as well as sleep, perceptions, and movement. Depending on which type of Lewy body dementia you have, it can cause movement-related symptoms before or after the cognitive symptoms of dementia.


There are treatments for both cognitive and movement-related symptoms of Lewy body dementia, but there is no cure. Even with treatment, thinking and memory will gradually get worse over time.

Types of Lewy Body Dementia

Depending on when you develop cognitive and movement-related symptoms, you may be diagnosed with one of the following types of Lewy body dementia:

  • Dementia with Lewy bodies
  • Parkinson’s disease dementia

Dementia with Lewy bodies means that you develop cognitive symptoms along with other symptoms of Lewy body dementia, which may include movement-related symptoms like a tremor.

Parkinson’s disease dementia means that you develop movement-related symptoms that lead to a diagnosis of Parkinson’s disease, and then years later develop cognitive symptoms that lead to a dementia diagnosis.

Both types of Lewy body dementia are caused by the same kind of changes in the brain, and eventually both will cause a similar range of potential symptoms.

Signs and Symptoms of Lewy Body Dementia

In Lewy body dementia, problems with thinking and memory may not be among the first symptoms, and may develop as the disease progresses.

Symptoms of Lewy body dementia can vary from person to person, and may include:

  • Visual or other hallucinations, which often occur early on and may include seeing shapes, animals, or people that aren’t there
  • Cognitive difficulties, including trouble with memory, problem solving, and attention
  • Episodes of confusion, drowsiness, long periods of staring into space, or disorganized speech that may come and go throughout the day
  • Movement disorders that resemble symptoms of Parkinson’s disease, such as slowed movement, rigid muscles, tremor, or a shuffling walk
  • Acting out dreams while still asleep
  • Problems with regulation of body functions, resulting in dizziness, poor control of body temperature, difficulty swallowing, incontinence, or constipation
  • Depression
  • Apathy (loss of motivation)

Causes and Risk Factors of Lewy Body Dementia

Lewy body dementia develops when abnormal clumps of a protein called alpha-synuclein build up in the brain. These clumps, called Lewy bodies, disrupt normal brain function and lead to the widespread death of neurons (brain cells).

Lewy bodies are named for Friedrich Lewy, an eminent German-born neurologist. In 1912, he discovered the abnormal protein deposits now called Lewy bodies in the brains of people with Parkinson’s disease.

Lewy body dementia causes the death of neurons that produce two key neurotransmitters, or brain chemicals: acetylcholine and dopamine. Acetylcholine is important for learning and memory, while dopamine plays a role in thinking, movement, motivation, sleep, and mood.

It’s unclear why exactly Lewy bodies form in the brains of some people. But the following factors are linked to an increased risk of Lewy body dementia.

  • Age: older than 60
  • Male sex
  • A family history of Lewy body dementia or Parkinson’s disease
  • REM sleep behavior disorder

While certain genetic variants have been linked to a higher risk of Lewy body dementia in some families, these genes are not known to cause the condition in most people. Right now, there is no genetic test that can predict a person’s risk of developing Lewy body dementia.

How Is Lewy Body Dementia Diagnosed?

It can be difficult to get an accurate diagnosis of Lewy body dementia, since there isn’t a simple test for the condition. A diagnosis will be based on your symptoms, as well as ruling out other health conditions that could be causing them.

To be diagnosed with Lewy body dementia, you need to experience gradual cognitive decline along with at least two of the following issues:

  • Frequent changes in alertness and ability to think
  • Visual hallucinations
  • Movement-related symptoms
  • REM sleep behavior disorder (acting out dreams during sleep)
Your doctor may perform or request the following tests or procedures to confirm your diagnosis.

  • Neurological and Physical Exam Your doctor will examine your reflexes, strength, balance, walking, eye movements, and more.

  • Neuropsychological Testing Certain tests can identify what brain regions are affected while evaluating memory and cognitive function.
  • Blood Tests Your doctor may check levels of hormones, vitamins, or other blood markers that could be linked to cognitive changes.
  • Sleep Study Undergoing various tests while you sleep may identify a sleep disorder that could be responsible for certain cognitive changes.
  • Brain Imaging Certain brain scans, such as MRI or CT, may help rule out other causes of dementia or movement symptoms. Another type of scan, PET, may help diagnose Lewy body dementia.

The first step in getting a diagnosis of Lewy body dementia is typically to talk with your primary care doctor about your symptoms. Your doctor may then refer you to a neurologist or other specialist, such as a geriatrician, who may be more skilled at diagnosing Lewy body dementia.

Treatment and Medication Options for Lewy Body Dementia

There is currently no cure for Lewy body dementia, but treatments are available to help treat many of its symptoms. Drug treatments may help with cognitive symptoms, hallucinations and delusions, movement-related symptoms, and REM sleep behavior disorder.

You may also benefit from physical therapy, counseling, and changes to your home to help with everyday tasks.

Medication Options

A wide range of drugs may be used to treat Lewy body dementia. Typically, the choice of medications will be based on what symptoms you experience.

Cholinesterase inhibitors are a group of drugs originally approved to help with memory loss, confusion, and problems with thinking and reasoning in Alzheimer’s disease. They may also help reduce hallucinations and delusions in Lewy body dementia, and include:

  • donepezil (Aricept)
  • rivastigmine (Exelon)
  • galantamine (Razadyne)
Sometimes, a related drug called memantine (Namenda) is added to a cholinesterase inhibitor to help boost cognitive function in moderate to severe dementia.

For movement-related symptoms, your doctor may prescribe a Parkinson’s disease medication called carbidopa-levodopa (Sinemet, Parcopa, Stalevo). But because of serious side effects like hallucinations and delusions, this drug must be used with caution.

To treat REM sleep behavior disorder, a drug called clonazepam (Klonopin) may be taken at night. The hormone melatonin may also help, on its own or in combination with clonazepam.

To treat hallucinations, delusions, agitation, and other behavioral symptoms, your doctor may prescribe what are known as atypical antipsychotic drugs. But these drugs may cause potentially severe side effects, so they should be used at the lowest dose possible for the shortest time needed to control symptoms.

 Two drugs in this category are considered to have the best safety profile for Lewy body dementia.

  • clozapine (Clozaril)
  • quetiapine (Seroquel)
A newer atypical antipsychotic medication called pimavanserin (Nuplazid) is approved for the treatment of Parkinson’s disease-related psychosis. One study showed that pimavanserin could be effective for the treatment of several types of dementia-related psychosis, including psychosis due to Lewy body dementia.

Traditional (typical) antipsychotic medications can be dangerous for people with Lewy body dementia and should not be used. These drugs can cause severe fever, extreme movement-related symptoms, sedation, and even death.

Other Therapies

Sometimes, people with Lewy body dementia may benefit from non-drug therapies to address certain issues, such as:

  • Physical therapy, to help improve strength, flexibility, and walking
  • Speech therapy, to improve poor enunciation, low voice volume, or swallowing difficulties
  • Occupational therapy, to help maintain skills and independence
  • Individual or family psychotherapy, to help manage emotions and behavioral symptoms
  • Support groups, to get emotional support and share practical advice
While antipsychotic drugs may be needed in some cases to help control hallucinations and delusions in Lewy body dementia, they can also worsen cognitive symptoms. For this reason, it’s often best to try other approaches first, such as:

  • Tolerating hallucinations, if they don’t disturb the person
  • Reducing clutter and noise, which can cause distress
  • Offering reassurance and validating the person’s concerns
  • Avoiding correcting or quizzing the person
  • Keeping tasks simple and focusing on small successes
  • Following routines and structure throughout the day

Complementary and Integrative Therapies

In addition to mainstream drug and non-drug therapies, people with Lewy body dementia may benefit from other practices such as:

  • Music therapy or aromatherapy, to reduce anxiety and improve mood
  • Pet therapy, to help improve behavior and mood
  • Massage therapy, to reduce muscle tension and improve mood

Prognosis and Outlook for Lewy Body Dementia

Lewy body dementia is progressive, meaning that it gets worse gradually over time. As it gets worse, a person may experience severe loss of cognitive function, aggressive behavior, and extreme movement-related symptoms. On average, death occurs about 7 to 8 years after symptoms begin.

But it’s not possible to predict how long someone with Lewy body dementia will live, or how quickly the disease will progress. The rate of progression depends on many factors, including a person’s general health and any other health conditions they may have.

 With an early diagnosis and effective treatment, it’s possible to live as long as 20 years after a diagnosis of Lewy body dementia.

Research and Statistics: How Many People Have Lewy Body Dementia?

It’s estimated that about 1.4 million Americans have Lewy body dementia, making it the second most common form of dementia after Alzheimer’s disease. Lewy body dementia accounts for between 4 and 16 percent of all dementia cases seen by healthcare providers.

Lewy body dementia typically affects adults ages 50 and older, and your risk grows with advancing age. In people ages 65 and older, it’s one of the most common forms of dementia.

Related Conditions

Lewy body dementia shares many similarities with Parkinson’s disease, and the two conditions often overlap. Many people with Parkinson’s will eventually develop Parkinson’s disease dementia (one of the two types of Lewy body dementia), although this is not an inevitable part of Parkinson’s progression.

When someone develops cognitive and movement-related symptoms around the same time (the other form of Lewy body dementia, known as dementia with Lewy bodies), they may be wrongly diagnosed with Parkinson’s disease if their cognitive symptoms are overlooked. This can lead to a delay in getting the right treatment for Lewy body dementia.

The Takeaway

  • Lewy body dementia causes both cognitive and movement-related symptoms, along with behavioral changes that may include frequent changes in alertness, hallucinations and delusions, and aggressive behavior.
  • Movement-related symptoms in Lewy body dementia resemble those of Parkinson’s disease, so it’s important to check for cognitive symptoms to get an accurate diagnosis.
  • Treatment for Lewy body dementia will depend on your symptoms, and often includes drugs to address both cognitive and movement-related symptoms.
  • While Lewy body dementia gets worse over time, getting an early diagnosis and effective treatment may delay its progression.

Common Questions & Answers

What’s the difference between Alzheimer’s disease and Lewy body dementia?

Both involve the buildup of protein clumps in the brain, but they’re caused by different disease processes and lead to different symptoms. In addition to cognitive decline, Lewy body dementia often causes movement-related symptoms and frequent changes in alertness.

Parkinson’s disease and Lewy body dementia are caused by similar disease processes, but in Parkinson’s disease, movement-related symptoms occur years before any cognitive symptoms. When cognitive decline eventually occurs in Parkinson’s disease, it’s known as Parkinson’s disease dementia.

In addition to dementia, Lewy body dementia often causes movement-related symptoms such as a tremor or an affected way of walking. Other symptoms can include episodes of reduced alertness throughout the day, visual hallucinations, delusions (false beliefs), and aggressive behavior.

There are treatments for many of the symptoms of Lewy body dementia, including cognitive impairment, movement-related symptoms, and hallucinations. But even with treatment, Lewy body dementia gets worse over time, eventually causing worsening symptoms and death.

It’s impossible to predict how long an individual with Lewy body dementia will live, or how quickly the disease will progress. The average time between diagnosis and death is about 7 to 8 years, but some people live much longer.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Lewy Body Dementia. Mayo Clinic. June 2, 2023.
  2. What Is Lewy Body Dementia? Lewy Body Dementia Association.
  3. Lewy Body Dementia: Causes, Symptoms, and Diagnosis. National Institute on Aging. January 27, 2025.
  4. Lewy Body Dementia. Mayo Clinic. June 2, 2023.
  5. How Is Lewy Body Dementia Treated and Managed? National Institute on Aging. January 27, 2025.
  6. Treatment. Lewy Body Dementia Association.
  7. Treatment of Behavioral Symptoms: When to Consider Antipsychotic Medications in LBD. Lewy Body Dementia Association.
  8. Tariot PN et al. Trial of Pimavanserin in Dementia-Related Psychosis. New England Journal of Medicine. July 21, 2021.
  9. Treatment Options. Lewy Body Dementia Association.
  10. Diagnosis and Prognosis. Lewy Body Dementia Association.
  11. Lewy Body Dementia. Cleveland Clinic. August 18, 2022.
  12. About LBD. Lewy Body Dementia Association.
  13. Dementia with Lewy Bodies. Parkinson's Foundation.
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