Lewy body dementia (LBD) is a progressive brain disorder that can affect thinking, movement, sleep, behavior, mood and automatic body functions such as blood pressure and digestion.
It is associated with abnormal deposits of a protein called alpha-synuclein inside brain cells. These deposits are known as Lewy bodies.
Lewy body dementia is one of the most common causes of dementia, although it can be difficult to diagnose because some symptoms overlap with Alzheimer’s disease, Parkinson’s disease and psychiatric conditions.
Symptoms vary considerably between individuals. Changes in attention and alertness, detailed visual hallucinations, REM sleep behavior disorder and Parkinson-like movement problems are particularly characteristic.
What Is Lewy Body Dementia?
According to the National Institute on Aging, Lewy body dementia is associated with abnormal deposits of alpha-synuclein in the brain.
These deposits can affect chemicals involved in thinking, movement, mood, behavior, sleep and other body functions.
More than one million people in the United States are estimated to be living with LBD.
The condition generally begins in people aged 50 or older, although younger people can occasionally develop it.
Lewy body dementia is progressive, which means symptoms tend to become more significant over time. However, the pattern and speed of progression can differ greatly between individuals.
Two Forms of Lewy Body Dementia
Lewy body dementia is an umbrella term that includes two closely related diagnoses:
- Dementia with Lewy bodies (DLB)
- Parkinson’s disease dementia (PDD)
The two conditions share many biological and clinical features.
The main distinction involves the timing of cognitive and movement symptoms.
Dementia With Lewy Bodies
In dementia with Lewy bodies, cognitive symptoms develop before, at about the same time as, or relatively soon after Parkinson-like movement symptoms.
Changes may involve attention, visual perception, planning, problem-solving and alertness.
Visual hallucinations and REM sleep behavior disorder are also common.
Parkinson’s Disease Dementia
Some people who have established Parkinson’s disease later develop significant cognitive impairment.
When dementia develops more than a year after the onset of Parkinson’s movement symptoms, doctors may diagnose Parkinson’s disease dementia.
Not everyone with Parkinson’s disease develops dementia.
Over time, people with DLB and Parkinson’s disease dementia can experience many similar symptoms.
Lewy Body Dementia Symptoms
Not everyone experiences every symptom.
The severity and timing of Lewy body dementia symptoms can also vary substantially.
Changes in Thinking and Attention
Cognitive symptoms may include:
- Difficulty concentrating
- Problems with planning and problem-solving
- Reduced ability to multitask
- Difficulty judging distances or spatial relationships
- Confusion
- Difficulty with language or numbers
- Memory problems, particularly as the condition progresses
Memory loss may be less prominent in the early stages than it is in Alzheimer’s disease.
Fluctuating Cognition and Alertness
One of the characteristic features of LBD is a noticeable fluctuation in attention and alertness.
A person may appear relatively alert and engaged at one time and then become unusually sleepy, confused or difficult to engage later the same day.
Possible signs include:
- Staring into space
- Periods of significant drowsiness
- Long daytime naps
- Disorganized speech or thinking
- Large changes in concentration from one period to another
These fluctuations can sometimes resemble delirium, which is one reason diagnosis can be difficult.
Visual Hallucinations
Recurrent visual hallucinations are common and can occur relatively early.
People may see:
- People who are not present
- Children
- Animals
- Objects
- Shapes or patterns
The hallucinations can be detailed and realistic.
Some people are aware that what they see is not real, while others believe the hallucination is actually happening.
Read more about hallucinations and dementia.
Movement Problems
Parkinson-like movement symptoms are another important feature.
These may include:
- Slowed movement
- Muscle rigidity or stiffness
- A shuffling walk
- Difficulty starting movement
- Periods of freezing while walking
- Resting tremor
- Poor balance
- Falls
- Stooped posture
- Reduced facial expression
- A weak voice
- Smaller handwriting
- Difficulty swallowing
Not everyone with LBD develops significant movement symptoms at the beginning of the condition.
REM Sleep Behavior Disorder
REM sleep behavior disorder, or RBD, is particularly associated with Lewy body disease.
During normal REM sleep, the body temporarily suppresses most muscle movement.
With RBD, this suppression does not work normally, so a person may physically act out their dreams.
They may:
- Talk or shout while sleeping
- Kick
- Punch
- Flail their arms
- Fall out of bed
RBD can sometimes develop years before noticeable cognitive symptoms.
Because the person and their bed partner can be injured, suspected REM sleep behavior disorder should be discussed with a healthcare professional.
Other sleep problems can include insomnia and excessive daytime sleepiness.
Changes in Automatic Body Functions
LBD can affect the autonomic nervous system, which controls functions the body normally manages automatically.
Possible symptoms include:
- Low blood pressure when standing
- Dizziness
- Fainting
- Constipation
- Urinary problems
- Sexual dysfunction
- Changes in sweating
- Difficulty regulating body temperature
Low blood pressure and balance problems can increase the risk of falls.
Mood and Behavioral Symptoms
Some people also experience:
- Depression
- Anxiety
- Apathy or loss of motivation
- Delusions
- Suspicion or paranoia
- Agitation
Behavioral changes should be assessed carefully because pain, infection, constipation, medication effects, dehydration or changes in the environment can also contribute.
What Causes Lewy Body Dementia?
Scientists do not yet fully understand why Lewy bodies develop.
The alpha-synuclein protein normally exists in the brain, but in Lewy body disease it accumulates abnormally inside nerve cells.
Researchers continue to study how these deposits interfere with communication between brain cells and contribute to cell damage.
Lewy bodies are also found in Parkinson’s disease.
Some people with LBD have other brain changes as well, including amyloid plaques and tau tangles associated with Alzheimer’s disease.
This means more than one disease process can occur in the same brain.
Lewy Body Dementia Risk Factors
There is no single factor that determines whether someone will develop LBD.
Possible risk factors include:
Age
Risk generally increases with age.
Most people diagnosed with the condition are over 50.
Sex
Current evidence suggests that LBD occurs somewhat more often in men than women.
Family History and Genetics
Most people with LBD do not have a strong family history of the condition.
However, researchers have identified genetic variations that may influence susceptibility, and rare families can have stronger inherited links.
Having a genetic risk factor does not mean that a person will necessarily develop the condition.
REM Sleep Behavior Disorder
REM sleep behavior disorder is strongly associated with diseases involving abnormal alpha-synuclein, including LBD and Parkinson’s disease.
However, not everyone with RBD will develop one of these disorders.
How Does Lewy Body Dementia Progress?
There is no universal three-stage system that accurately predicts the course for every person.
The progression can be particularly difficult to predict because cognitive abilities and alertness may fluctuate.
For practical care planning, families may still find it useful to think broadly in terms of earlier, middle and later periods.
Earlier Changes
Earlier symptoms may include:
- Changes in attention or planning
- Visual hallucinations
- REM sleep behavior disorder
- Mild movement problems
- Changes in mood
- Periods of confusion
A person may remain relatively independent but need support with more complicated tasks.
Increasing Support Needs
As the disease progresses, a person may experience:
- Greater cognitive impairment
- More significant movement problems
- Falls
- Communication difficulties
- Increasing assistance with everyday activities
- More prominent autonomic symptoms
Later Lewy Body Dementia
In later stages, a person may require extensive assistance with:
- Walking and mobility
- Eating and swallowing
- Dressing
- Bathing
- Toileting
- Communication
Individual progression varies considerably, so care should be based on the person’s current needs rather than a rigid stage label.
You can read more in our guide to Lewy body dementia stages and progression.
How Is Lewy Body Dementia Diagnosed?
Diagnosis can be challenging because symptoms overlap with Alzheimer’s disease, Parkinson’s disease and some psychiatric conditions.
There is currently no single routine test that can definitively diagnose LBD during life.
A medical assessment generally combines several types of information.
Medical and Symptom History
Doctors may ask about:
- Changes in memory and thinking
- Fluctuations in alertness
- Hallucinations
- Movement symptoms
- Sleep behavior
- Falls or fainting
- Blood pressure problems
- Mood and behavior
- Current medications
Information from a spouse, family member or caregiver can be especially helpful because the person may not recognize all of their own symptoms.
The Four Core Clinical Features
Doctors pay particular attention to four characteristic features associated with dementia with Lewy bodies:
- Fluctuating cognition, attention and alertness
- Recurrent, detailed visual hallucinations
- REM sleep behavior disorder
- Spontaneous Parkinson-like movement symptoms
The presence of these features can substantially strengthen the diagnosis.
Cognitive and Neuropsychological Testing
Cognitive testing may assess:
- Attention
- Memory
- Planning
- Problem-solving
- Visual and spatial ability
- Language
People with LBD may have particularly noticeable difficulty with attention, executive function and visual-spatial tasks.
Physical and Neurological Examination
Doctors may assess:
- Walking
- Balance
- Muscle tone
- Strength
- Reflexes
- Eye movements
- Tremor
Blood Tests
Blood tests can help rule out other conditions that may contribute to cognitive symptoms, such as thyroid disorders or vitamin B12 deficiency.
Brain Imaging
MRI or CT scans may help identify strokes, tumors or other structural abnormalities.
Specialized PET or SPECT imaging may sometimes provide additional evidence by examining patterns of brain metabolism or dopamine activity.
A brain scan alone does not diagnose LBD.
Sleep Studies
A formal sleep study may be recommended when REM sleep behavior disorder is suspected.
Documenting REM sleep without the normal loss of muscle activity can provide useful diagnostic information.
Lewy Body Dementia Treatment
There is currently no cure for LBD.
Treatment therefore focuses on managing individual symptoms, maintaining independence and improving quality of life.
Because treatment for one symptom can sometimes worsen another, medical management often requires particular care.
The National Institute on Aging recommends an individualized approach involving medications, therapies and supportive care.
Medicines for Cognitive Symptoms
Cholinesterase inhibitors used for Alzheimer’s disease may also help some people with LBD.
These include:
- Rivastigmine
- Donepezil
- Galantamine
Rivastigmine is FDA-approved for cognitive symptoms associated with Parkinson’s disease dementia.
Other cholinesterase inhibitors may sometimes be prescribed off-label for people with LBD.
They may help some individuals with thinking, alertness or behavioral symptoms, but they can also cause side effects.
Movement Symptoms
Levodopa may improve movement problems such as rigidity and slowness in some people.
However, Parkinson’s medications can sometimes worsen hallucinations, confusion or other behavioral symptoms.
Doctors may therefore start with a low dose and weigh movement benefits against possible cognitive or psychiatric side effects.
Important Medication Warning With Lewy Body Dementia
People with Lewy body dementia can be unusually sensitive to antipsychotic medications.
These medicines are sometimes used for severe hallucinations, delusions or agitation, but they can produce serious reactions in people with LBD.
The Lewy Body Dementia Association warns that traditional antipsychotic medicines such as haloperidol can cause severe adverse effects and generally should be avoided in LBD.
Possible reactions can include:
- Severe worsening of movement symptoms
- Marked confusion
- Heavy sedation
- Low blood pressure
- Severe muscle rigidity
- Potentially life-threatening neuroleptic malignant syndrome
Some newer antipsychotic medicines may occasionally be considered when symptoms are severe or dangerous, but they also require considerable caution.
Treatment decisions should be made by a clinician who understands Lewy body dementia and the person’s individual circumstances.
Managing Hallucinations
Hallucinations do not always require medication.
If they are not frightening or dangerous, reassurance and environmental changes may sometimes be preferable.
Before prescribing medication, clinicians may look for:
- Pain
- Infection
- Medication side effects
- Sleep deprivation
- Dehydration
- Constipation
- Overstimulation
Treating the underlying trigger can sometimes reduce behavioral symptoms.
Treating REM Sleep Behavior Disorder
Sleep treatment should be individualized.
Melatonin may be considered for some people with REM sleep behavior disorder.
Low-dose clonazepam can also be effective in selected patients, although it can increase dizziness, unsteadiness and cognitive problems.
A healthcare professional should weigh these risks carefully.
Making the sleeping environment safer can also reduce the risk of injury.
Managing Low Blood Pressure and Autonomic Symptoms
Orthostatic hypotension can cause dizziness and fainting when standing.
Depending on the person’s health, a clinician may recommend measures such as:
- Rising slowly from sitting or lying
- Compression stockings
- Leg elevation
- Adjusting medications that lower blood pressure
- Increasing fluid or salt intake when medically appropriate
Salt and fluid intake should only be increased when a healthcare professional confirms that it is safe, particularly for people with heart, kidney or blood pressure problems.
Therapies and Supportive Care
Non-drug approaches can play an important part in maintaining function and quality of life.
Physical Therapy
Physical therapy may help with:
- Walking
- Strength
- Balance
- Flexibility
- Fall prevention
Occupational Therapy
Occupational therapy can help a person adapt everyday activities and their home environment to remain as independent as possible.
Speech and Language Therapy
Speech therapy can help with communication difficulties and may also assess swallowing problems.
Meaningful Activities
Activities such as music, art, gentle exercise, social contact and familiar hobbies can support enjoyment, engagement and wellbeing.
These approaches should be viewed as supportive rather than treatments that slow or cure the underlying disease.
Creating a Supportive Home Environment
A calm and predictable environment may reduce confusion and stress.
Helpful strategies can include:
- Keeping routines consistent
- Reducing excessive noise and clutter
- Providing good lighting
- Using grab rails and other fall-prevention measures
- Keeping frequently used objects in familiar places
- Giving one instruction at a time
- Allowing extra time to respond
Read more about creating a dementia-friendly home.
Living With Lewy Body Dementia
A diagnosis does not mean that someone immediately loses their independence.
Many people continue participating in family life, hobbies and everyday activities for a considerable period.
Useful early steps can include:
- Learning about the condition
- Building an experienced healthcare team
- Reviewing medications regularly
- Making the home safer
- Discussing driving safety
- Planning financial and legal arrangements
- Discussing future healthcare preferences
- Identifying family, community and professional support
Whenever possible, the person with LBD should remain actively involved in decisions about their own care.
When to See a Lewy Body Dementia Specialist
Because LBD can resemble other neurological and psychiatric conditions, specialist assessment can be particularly valuable.
A primary care doctor may refer a person to:
- A neurologist
- A cognitive or behavioral neurologist
- A movement-disorder neurologist
- A geriatrician
- A geriatric psychiatrist
- A neuropsychologist
People preparing for an appointment may find it helpful to bring:
- A detailed list of symptoms
- Information about when each symptom began
- A list of medications and supplements
- Medical history
- Details about sleep and movement problems
- Questions for the clinician
See our guide to finding a Lewy body dementia specialist.
Lewy Body Dementia Prognosis and Life Expectancy
The course of LBD varies greatly.
According to the National Institute on Aging, the average time from diagnosis to death is approximately five to seven years, but reported survival can range from about two to 20 years.
These numbers are population averages and cannot predict how long an individual will live.
Factors that can influence prognosis include:
- Age
- Overall health
- Severity of symptoms
- Mobility
- Falls
- Swallowing difficulties
- Other medical conditions
Later complications can include pneumonia, swallowing difficulties, falls, immobility and problems maintaining adequate nutrition.
Can Lewy Body Dementia Be Prevented?
There is currently no established way to prevent LBD.
Researchers continue to investigate alpha-synuclein, genetics, biomarkers, sleep disorders and other factors that may eventually improve prevention, diagnosis and treatment.
Maintaining good overall cardiovascular and physical health remains worthwhile for general brain health, but it should not be presented as a proven way to prevent Lewy body dementia.
Caring for Someone With Lewy Body Dementia
Caregiving can become increasingly demanding because LBD can affect cognition, mobility, sleep, behavior and automatic body functions at the same time.
Helpful approaches include:
Communicate Clearly
Speak calmly and use short, straightforward sentences.
Give the person enough time to process what has been said and respond.
Too many questions or choices at once can increase confusion.
More information is available in our guide to dementia and communication.
Respond to Hallucinations With Reassurance
Arguing about whether a hallucination is real may increase distress.
If the person is safe, acknowledging their feelings and offering reassurance may be more helpful.
Watch for Sudden Changes
A sudden deterioration should not automatically be assumed to be progression of LBD.
Infection, dehydration, constipation, pain, medication effects or another medical condition can cause abrupt changes.
These should be medically assessed.
Support the Caregiver
Caregivers also need rest, healthcare and social support.
Family assistance, respite services, support groups and professional care can help reduce caregiver strain as needs increase.
Explore our dementia care resources for more practical caregiving information.
Lewy Body Dementia: The Bottom Line
Lewy body dementia is a progressive neurological disorder associated with abnormal deposits of alpha-synuclein in the brain.
It includes both dementia with Lewy bodies and Parkinson’s disease dementia.
Characteristic symptoms include fluctuating attention and alertness, recurrent visual hallucinations, REM sleep behavior disorder and Parkinson-like movement changes. Autonomic symptoms, mood changes and sleep problems are also common.
There is currently no cure, but some cognitive, movement, sleep and behavioral symptoms may respond to treatment.
Medication management requires particular care because people with LBD can be highly sensitive to certain drugs, especially antipsychotic medications.
Accurate diagnosis, specialist medical care, rehabilitation, a supportive environment and appropriate help for caregivers can improve safety and quality of life throughout the course of the disease.
For more information about dementia symptoms, care, treatment and related conditions, browse the Dementia Resource Library.