Dementia with Lewy bodies

What is dementia with Lewy bodies?

Dementia with Lewy bodies (DLB) is a progressive brain disorder that causes problems with thinking, movement, sleep, mood, and behavior. "Progressive" means symptoms get worse over time. It is one of the two types of Lewy body dementia (LBD); the other is Parkinson's disease dementia.

DLB accounts for 15 percent of all cases of dementia in the United States, making it the second most common type, after Alzheimer's disease. Over one million people in the United States are diagnosed with dementia with Lewy bodies.

Symptoms of dementia with Lewy bodies

DLB symptoms usually start in people older than 50, but cases in younger people have been reported. Symptoms vary and progress differently from person to person.

The most common symptoms of dementia with Lewy bodies affect movement, cognition (mental function), sleep, mood, behavior, and automatic (autonomic) processes such as heart rate, breathing, blood pressure, and body temperature regulation through sweating.

Causes of dementia with Lewy bodies

Lewy bodies are abnormal clumps of a protein called alpha-synuclein that build up in and damage nerve cells in the brain. Symptoms gradually worsen over time as more Lewy bodies accumulate in the brain.

Researchers don't fully understand what causes Lewy bodies to form or how they destroy nerve cells in the brain. The current thought is that a combination of genetics, environmental risk factors, and the natural aging process all interact to cause DLB to develop.

Certain variants of the APOE and GBA genes increase a person's likelihood of developing dementia with Lewy bodies. However, these genetic variants don't guarantee that a person will develop DLB.

Dementia with Lewy bodies diagnosis

There are no medical tests for diagnosing dementia with Lewy bodies. Similarities with other conditions—Parkinson's disease and Alzheimer's disease—can make accurate diagnosis of dementia with Lewy bodies more challenging.

The criteria for an DLB diagnosis include a progressive decline in cognitive ability, plus two or more of the following symptoms:

  • Fluctuating alertness and cognition
  • Parkinson-like symptoms
  • REM sleep behavior disorder
  • Visual hallucinations

Several specialists may be involved in forming a "probable diagnosis," including neurologists, who care for disorders of the brain and nervous system, and neuropsychologists, who study how disorders of the brain affect brain function and cognition.

Your neurologist will ask about your personal and family medical histories, current medications, and how your symptoms affect your daily life. They will perform a physical examination, including assessing your cognition, movement, reflexes, sensations, strength, and coordination.

Your neurologist may conduct further tests to support the diagnosis of dementia with Lewy bodies if there are atypical features. These tests are typically not needed to make a diagnosis.

Dementia with Lewy bodies treatment

There is no cure for DLB. Treatments may help manage symptoms and improve your quality of life.

Care for dementia with Lewy bodies at Penn Medicine

The Lewy Body Dementia Association recognizes Penn Medicine's Movement Disorders Center as one of 22 Research Centers of Excellence. This designation recognizes our commitment to DLB research and to providing the most advanced diagnostic and treatment options for people with DLB.

As the leading movement disorders center in the Philadelphia region, we provide comprehensive medical, rehabilitative, and psychological care for thousands of patients with diseases like Lewy body dementia, including both Parkinson's disease dementia and dementia with Lewy bodies, each year.

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