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Lewy body dementia is a progressive neurodegenerative disorder brought on by an excess of the protein alpha-synuclein in the brain. These deposits, known as Lewy bodies, can inhibit the production of neurotransmitters leading to symptoms involving movement, cognition, behavior, and mood.

There are two types of Lewy body dementia: dementia with Lewy bodies, or DLB, and Parkinson's disease dementia. In both forms of the condition, the effects on the brain are similar; the primary difference is the timing of the emergence of movement and cognitive symptoms.

As a progressive condition, the symptoms of Lewy body dementia gradually emerge and worsen over time, and no treatment can halt the progression of the disorder.


Lewy body dementia affects an individual's cognition, movement, sleep, and behavior, although not every patient will experience every symptom in every category. In the early stages of the condition, symptoms may be mild, allowing people to continue to function relatively normally. But as symptoms advance, a patient will require greater assistance and care, and eventually may become entirely dependent on others.

According to the National Institutes of Health, the primary cognitive symptoms of the condition are:

  • Hallucinations. About 80 percent of people with LBD may see things that are not there. This is often an early sign of the condition. (Auditory hallucinations are less common in LBD.)
  • Unpredictable swings in attention or alertness. From one day to another, or at different times on the same day, an individual with LBD may present illogical or disorganized thinking or a lack of concentration.
  • Significant impairment of cognitive abilities related to daily functioning. A person with LBD may display confusion or illogic related to time and place, numbers, or judgment. General memory problems do not typically emerge early in the course of LBD, which is one way it can be distinguished from Alzheimer’s Disease.

The major symptoms of LBD affecting movement include:

  • Muscle rigidity or stiffness
  • Shuffling walk, slow movement, or freezing
  • Tremors or shaking at rest
  • Balance problems that can lead to falls
  • Stooped posture
  • Loss of coordination
  • Smaller, less legible handwriting
  • Limited facial expression
  • A weakened voice
  • Trouble with swallowing

The effects of LBD on sleep and sleep patterns often go undiagnosed, but they can and should be treated by a sleep specialist; individuals and their families should pay close attention to symptoms such as:

  • Rapid eye movement sleep behavior disorder, in which an individual reacts physically to their dreams.
  • Daytime sleepiness, such as falling asleep for multiple hours during the day.
  • Insomnia
  • Restless leg syndrome

Lewy body dementia can greatly affect an individual’s mood, outlook, and behavior patterns as the condition damages their cognitive abilities. Among the changes LBD can cause are:

  • Depression
  • Apathy
  • Anxiety, which can manifest in repeated questioning, or angst, or suspicion when routines change or a caretaker is not present.
  • Agitation and restlessness in the form of pacing or hand wringing, difficulty settling down, repetition of certain words or phrases, or general high irritability.
  • Delusions
  • Paranoia
What other symptoms might affect someone with Lewy body dementia?

Because of the condition’s effect on the nervous system, a range of bodily functions can be affected by LBD, leading to symptoms including changes in body temperature and blood pressure, dizziness or fainting, incontinence or constipation, a reduced sense of smell, and sexual dysfunction.

How does LBD progress in its early stages?

The emergence and progression of LBD is the primary difference between dementia with Lewy bodies (DLB) and Parkinson's disease dementia.

In DLB, cognitive symptoms often precede movement and motor effects, sometimes by a year or more. Initially, the cognitive changes they display may resemble those of Alzheimer’s disease; the eventual emergence of movement and motor symptoms is distinctive of the disorder.

For those living with Parkinson's disease dementia, cognitive symptoms do not typically emerge until a year, or sometimes multiple years, after the onset of movement and motor concerns, such as stiffness, tremors, and a shuffling gait. It is important to note that not all people with Parkinson's disease will develop dementia. While it cannot generally be predicted which Parkinson’s patients will develop dementia, many who live with Parkinson’s for many years will develop at least some degree of mild dementia.

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The cause of Lewy body dementia is unknown but clues may be emerging as researchers learn more about the progress of the condition. In an LBD patient, an accumulation of Lewy bodies is implicated in a loss of neurons that the body relies upon for the production of two essential neurotransmitters: acetylcholine, which has a role in learning and memory; and dopamine, which affects movement, sleep, behavior, cognition, and mood.

It is not easy to determine that a patient has Lewy body dementia, as the symptoms may be confused with those of Parkinson’s disease, Alzheimer’s, or other conditions.

How prevalent is Lewy body dementia?

LBD is the second most common progressive dementia condition after Alzheimer’s disease. For as many as 15 of every 100 people living with dementia, the cause is Lewy body dementia. The condition is believed to affect more than 1.4 million people in the United States, but that may be a conservative estimate as the condition is similar to other disorders and it may be underdiagnosed. Symptoms typically do not emerge until after age 50, and the disorder affects slightly more men than women.

What are the major risk factors for Lewy body dementia?

Age is the greatest risk factor but the presence of certain diseases or health conditions can also raise one’s risk, primarily Parkinson’s disease, but also REM sleep behavior disorder.


There is no cure for Lewy body dementia. However, medication and therapy can alleviate symptoms but not halt the condition’s progression.

What medications are used to treat Lewy body dementia?

As Lewy body dementia involves symptoms affecting movement, mood, and cognition, different medications may be prescribed to treat each.

For movement concerns, LBD patients may take medications prescribed to people living with Parkinson’s Disease, specifically levodopa, which is converted to dopamine in the brain, enabling someone to experience some relief from their symptoms. On its own, levodopa causes nausea, so it is combined with the drug carbidopa, which significantly lessens that side effect.

For cognitive symptoms, doctors may prescribe cholinesterase inhibitors, which are also taken by people living with Alzheimer’s Disease, and which can inhibit the breakdown of the neurotransmitter acetylcholine, which is important in memory and thinking processes. These drugs may also ease symptoms like hallucinations, delusions, and apathy.

For sleep issues, medication may be able to address certain symptoms. REM sleep behavior disorder, in which a patient physically and emotionally reacts to their dream while remaining asleep, may be treated with a low dose of clonazepam, which is also used to treat people experiencing seizures or panic attacks. LBD patients experiencing excessive daytime sleepiness may be prescribed a stimulant to help them stay awake until evening. People with LBD experiencing insomnia will be asked to avoid naps, increase daytime activity, and avoid caffeine and alcohol before being prescribed medication to aid in sleep, as those drugs may have disruptive side effects.

Treating behavioral and mood symptoms in people living with LBD is especially difficult, as patients may be experiencing hallucinations, delusion, stress, anxiety, frustration, fear, and overwhelm, which may lead them to lash out at others verbally or physically, and resist treatment. Antidepressants and antipsychotics may be prescribed to people with LBD, but the latter, while potentially improving the quality of life for patients and their caregivers, can also have problematic side effects including the worsening of LBD movement symptoms, extreme sleepiness, and low blood pressure. Patients, caregivers, and physicians must discuss the pros and cons of antipsychotics for LBD and balance the risk of side effects with the potential harm and distress of leaving certain behavioral symptoms untreated.

What other therapies are used to treat LBD?

A patient and their immediate family or other caregivers will be encouraged to take part in physical, speech, and occupational therapy as well as mental health counseling, and to make changes to their home environment and daily routines.

The US National Institutes of Health/National Institute on Aging. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. The Lewy Body Dementia Association.
Last updated: 11/06/2023