What is dementia with Lewy bodies?

Dementia with Lewy bodies (DLB) is a form of progressive dementia caused by degeneration of the tissues in the brain.

People with DLB have a buildup of abnormal protein particles in their brain tissue, called Lewy bodies. Lewy bodies are also found in the brain tissue of people with Parkinson's disease (PD) and Alzheimer disease (AD). However, in these conditions, the Lewy bodies are generally found in different parts of the brain.

The presence of Lewy bodies in DLB, PD, and AD suggests a connection among these conditions. But scientists haven’t yet figured out what the connection is.

DLB affects a person’s ability to think, reason, and process information. It can also affect movement, personality and memory. DLB becomes more prevalent with age. It often starts when a person is in his or her 60s and 70s.  DLB is progressive, which means it continues to develop over time. There are several types of dementia with different causes.

What causes dementia with Lewy bodies?

Degeneration or deterioration of brain tissue causes dementia with Lewy bodies. DLB may be genetic, but it is not always clear why someone develops DLB. Lewy bodies in the brain affect substances called neurotransmitters. A neurotransmitter is a chemical that helps send signals from one nerve cell to another.

One type of neurotransmitter is dopamine. It helps transmit signals that cause muscle movement. Lewy bodies interfere with the production of dopamine. A lack of dopamine causes movement problems, such as those seen in Parkinson's disease.

Acetylcholine is another type of neurotransmitter found in the parts of the brain responsible for memory, thinking, and processing information. When Lewy bodies build up in these areas, they use up the acetylcholine, causing symptoms of dementia.

What are the symptoms of dementia with Lewy bodies?

The main sign of DLB is a progressive decline in things like memory, thinking, and problem solving. This decline is enough to affect the ability to work and do normal daily activities. Although memory may be affected, it isn’t usually as impaired as in someone with Alzheimer disease.

DLB is generally diagnosed when at least 2 of the following features are also present with dementia:

  • Changes in attention and alertness. These changes may last for hours or days. Signs of these changes include staring into space, lethargy, drowsiness, and disorganized speech. 
  • Visual hallucinations. These hallucinations recur and are very detailed. They generally don’t bother the person having them. 
  • Movement symptoms consistent with Parkinson's disease (PD), such as slow movement, shuffling gait, rigidity, and falls. The person may also have tremors, but not as pronounced as in a person with PD with dementia.

Other signs and symptoms seen in DLB include:

  • Depression
  • Sleep disorder that affects REM sleep, causing vivid dreams with body movement
  • Dizziness, feeling lightheaded, fainting, or falling
  • Urinary incontinence
In DLB, memory problems often occur later in the disease.

DLB can be confused with other forms of dementia, but it also has unique features, such as hallucinations and delirium.

The symptoms of DLB may look like other conditions. Always see a healthcare provider for a diagnosis.

How is dementia with Lewy bodies diagnosed?

Your healthcare provider may diagnose DLB based on medical history, a physical exam, and symptoms. He or she may do a complete medical history and physical exam, along with these tests:

  • Blood tests. These are to rule out conditions such as vitamin B12 deficiency and hypothyroidism (low levels of thyroid hormone).
  • Computed tomography (CT) scan. This imaging test uses X-rays to create pictures of cross-sections of the brain.


  • Electroencephalogram (EEG). An EEG measures the electrical activity of the brain.
  • Magnetic resonance imaging (MRI). This imaging test uses a large magnet and radio waves to look at organs and structures inside your body. MRIs are very useful for examining the brain.
  • Positron emission tomography (PET). PET may find chemical changes in an organ or tissue that can show the onset of a disease process before physical changes related to the disease can be seen with other imaging tests.
  • Neuropsychological assessments. These tests assess things such as attention span, memory, language and math skills, and problem-solving skills.
  • Psychiatric evaluation. This may be done to rule out a psychiatric condition that may look like dementia.

How is dementia with Lewy bodies treated?

Dementia with Lewy bodies (DLB) has no cure. Treatment involves managing symptoms.

Medicines used to treat Alzheimer disease (AD) and Parkinson's disease (PD) may also be used to treat DLB. Other treatments, such as supportive care, physical therapy, psychotherapy, and behavioral interventions, may also be used.

It’s important that the healthcare provider treating a person with DLB be familiar with all aspects of the disease. Other specialists are often involved in care. Because DLB shares features with AD and PD, those features will need to be treated. Many people with DLB, however, can’t tolerate some of the medicines for AD or PD. Caution must be used when prescribing certain medicines for DLB.

Living with dementia with Lewy bodies

Interventions used in other forms of dementia may also help people living with dementia with Lewy bodies (DLB). These include using glasses or hearing aids as needed, educating the patient and family, providing a structured environment, and teaching behavioral interventions. These will change over time as the disease progresses.

Hallucinations may be managed by ignoring them and educating the caregiver(s) about them. Improving lighting and keeping the patient around other people also helps.

It’s important to work with a healthcare provider familiar with DLB and the many aspects of the disease. Other specialists are often involved, too.

When should I call my healthcare provider?

Talk with your healthcare providers about when it's important to call them. Your healthcare providers will likely advise calling if your symptoms become worse, or if you have obvious or sudden changes in behavior, personality, or speech. This includes mood changes, such as increasing depression or feeling suicidal.

Key points about dementia with Lewy bodies

  • Dementia with Lewy bodies (DLB) is a form of progressive dementia that affects a person’s ability to think, reason, and process information.
  • DLB is caused by degeneration or deterioration of brain tissue.
  • DLB has 3 features that distinguish it from other forms of dementia:
    • Changes in mental functioning, particularly alertness and attention, which may look like delirium
    • Recurrent visual hallucinations
    • Parkinson-like movement symptoms, such as rigidity and lack of spontaneous movement
  • There is no cure for DLB. Treatment involves managing symptoms.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.