What Is Lewy Body Dementia?
Lewy body dementia (LBD) is a brain disorder that can lead to problems with thinking, movement, behavior, and mood. Visual hallucinations, or seeing things that are not there, are a common symptom, and tend to happen early on.
More than 1 million people in the United States are diagnosed with LBD, which is one of the most common forms of dementia. It is a progressive disease, meaning symptoms start slowly and worsen over time.
Although younger people can have LBD, it typically begins at age 50 or older. People with LBD live on average five to eight years — but may live as few as two years or as long as 20 years — from the time of diagnosis to death. How fast symptoms develop and change varies depending on the person’s overall health, age, and level of symptoms.
What Causes Lewy Body Dementia?
In people with LBD, abnormal clumps of a protein called alpha-synuclein accumulate in areas of the brain involved in thinking, memory, and movement. The clumps are called "Lewy bodies" after the doctor who discovered them. They build up inside neurons, or nerve cells, in the brain and cause the neurons not to work well and eventually die. Certain chemicals in the brain that act as messengers between cells are also affected. What causes these changes in the brain is not yet fully understood.
Most cases of LBD are not inherited and rarely does more than one family member have the disease. Certain genetic variants may increase the chance of developing dementia with Lewy bodies, but having a genetic variant does not mean that a person will definitely develop the disease.
What Are the Signs and Symptoms of Lewy Body Dementia?
The most common symptoms of LBD include changes in thinking abilities, movement, sleep, and behavior. The degree of symptoms can vary widely and people with LBD may not have every symptom. Common symptoms include:
- Trouble with attention, planning, multitasking, problem-solving, and reasoning. Memory problems are also common but may not be noticeable early on.
- Problems with visual and spatial abilities, such as judging distance and depth or misidentifying objects.
- Unpredictable changes in concentration, attention, alertness, and wakefulness.
- Visual hallucinations, which occur in up to 80% of people with LBD, often early on.
- Movement changes, such as tremor or muscle stiffness, known as parkinsonism.
- Sleep disorders, including rapid eye movement (REM) sleep behavior disorder in which a person seems to act out dreams while asleep, excessive sleep or lack of sleep, and restless leg syndrome.
- Depression, lack of interest, anxiety, ideas not based in reality, and other changes in mental health.
- Sensitivity to heat and cold, dizziness, poor sense of smell, and other changes in automatic functions of the body.
Individuals with mild symptoms can often function close to normally. As the disease progresses and thinking and movement abilities decline, people with LBD will need more help and may depend on caregivers full time.
What Are the Types of Lewy Body Dementia?
The two types of Lewy body dementia — dementia with Lewy bodies and Parkinson's disease dementia — are caused by the same underlying changes in the brain. Over time, these conditions may result in similar symptoms. The main difference is the timing of when thinking and movement symptoms begin.
In dementia with Lewy bodies, problems with thinking, unpredictable changes in attention and alertness, and visual hallucinations develop early in relation to movement symptoms, such as slow movement, difficulty walking, and muscle stiffness.
In Parkinson's disease dementia, movement symptoms start first and are consistent with a diagnosis of Parkinson’s disease. Later, problems with thinking and changes in mood and behavior develop. However, not everyone with Parkinson’s disease will develop dementia.
It's important to know which type of LBD a person has, both to tailor treatment to symptoms and to understand how the disease will likely progress. For example, some people with LBD may not experience significant movement problems, such as frequent falls and shaking, for several years, while others may have them early on. Knowing what to expect can help people with LBD and their families prepare for changes that may need to be made, for example, to help prevent falls.
This booklet provides an overview of Lewy body dementia and provides resources for coping.
How Is Lewy Body Dementia Diagnosed and Treated?
Dementia with Lewy bodies is often hard to diagnose early because symptoms may at first look like Alzheimer's or a mental illness such as schizophrenia. LBD can also occur alongside other forms of dementia. Talking to both the patient and family members or caregivers can help doctors make a diagnosis. It is important to tell the doctor about any symptoms involving thinking, movement, sleep, behavior, or mood.
To diagnose LBD, doctors may:
- Ask questions about a person’s medical history and symptoms.
- Perform physical exams and laboratory tests of blood and other fluids.
- Conduct assessments to evaluate memory and other mental functions.
- Do tests to rule out other conditions that could cause similar symptoms. These could include blood tests and brain imaging tests.
Although LBD currently cannot be prevented or cured, treatments may be able to help with some of the symptoms. A treatment plan may involve medications, physical and other types of therapy, and counseling. Changes to make the home safer, equipment to make everyday tasks easier, and social support are also important.
A skilled care team can suggest ways to improve quality of life for both people with LBD and their caregivers. A neurologist should be part of the care team and can help patients and their families work with other types of professionals.
Support groups can also be a valuable resource for people with LBD and their caregivers to share experiences and tips with others in the same situation. Nonprofit organizations and community organizations may provide online or in-person support groups. National Institute on Aging-funded Alzheimer’s Disease Research Centers also may offer education and support groups.
What Can You Do?
If you are concerned about symptoms of LBD, talk with your doctor or contact a dementia or movement disorders clinic at an academic medical center to find a specialist. If you or someone you know has been recently diagnosed, explore the resources on this website and linked below to find out more about the disease, care, support, and research. It’s important to plan ahead because symptoms can worsen quickly. Researchers are working to better understand LBD and related disorders to treat and prevent these diseases. Consider joining the effort: Researchers need volunteers with and without LBD for clinical trials and studies.
You could help discover new ways to treat and prevent Alzheimer’s and related dementias.
Find More Resources on Lewy Body Dementia
Explore the resources on this website and linked below to find more information from federal government agencies.
Learn more about LBD, treatment and management, and providing care for someone diagnosed.
Discover details about genetic variants associated with LBD and how to find a specialist.
Find information on the basics of LBD and links to more resources. Also available in Spanish.
Find information on dementia with Lewy bodies diagnosis and treatment, as well as clinical trials, patient organizations, and free publications.
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This content is provided by the National Institute on Aging (NIA), part of the National Institutes of Health. NIA scientists and other experts review this content to ensure it is accurate and up to date.