Stanford Center for Memory Disorders

What is Dementia with Lewy Bodies?

Dementia is a condition that affects your ability to think, reason, and process information. It can also affect your personality and memory. Dementia is progressive, which means it continues to develop over time. There are several types of dementia with different causes.

Of the forms of dementia caused by degeneration of the tissues in the brain, dementia with Lewy bodies (DLB) is a common type after Alzheimerís disease (AD). People with DLB have an accumulation of abnormal protein particles called alpha synuclein in their brain tissue. Alpha synuclein is also found in the brain tissue of people with Parkinsonís disease (PD) and multiple system atrophy (MSA), although the location in the brain is different in these conditions.

The presence of Lewy bodies in DLB, PD, and MSA suggests a connection among the conditions.

Facts about DLB

DLB was first recognized as a diagnosis in the 1980s. Because the signs and symptoms of DLB resemble those of other forms of dementia, researchers think that the number of diagnoses is lower than the number of cases that actually exist.

According to the National Institute of Neurological Disorders and Stroke (NINDS), DLB has three features that distinguish it from other forms of dementia:

Other than advanced age, no specific risk factors for DLB have been established. DLB generally appears between the ages of 50 to 85, but it has been seen in younger people. Men are affected by DLB slightly more often than women. If you have a family member with DLB, you are at a somewhat increased risk. Some studies have suggested that a healthy lifestyle might delay onset of dementia associated with increased age.

Causes of DLB

DLB is caused by degeneration of brain tissue. Lewy bodies in the brain affect substances called neurotransmitters. A neurotransmitter is a chemical that helps to transmit signals from one nerve cell to another.

One type of neurotransmitter is dopamine, which 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 PD.

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 lead to a deficiency in acetylcholine, causing symptoms of dementia.

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