Lewy body dementia (LBD) is a disease related to abnormal deposits of a protein called alpha-synuclein in the brain. These deposits, called Lewy bodies, affect chemicals in the brain responsible for thinking, movement, behavior, and mood.
LBDis one of the most common causes of dementia.
Diagnosing LBD is very difficult as it displays symptoms very similar to Alzheimer’s disease. Indeed, early Lewy body dementia symptoms are often confused with similar symptoms of Alzheimer’s and psychiatric disorders like schizophrenia. Adding to the difficulty in diagnosing this disease, is that LBD can occur alone or together with other brain disorders.
There are two basic diagnoses of LBD:
- Dementia with Lewy bodies,
- Parkinson’s disease dementia.
While there are slight differences, very similar biological changes in the brain occur. As the diseases advance, patients display symptoms of both diseases; LBD and Parkinson’s.
What Is A Lewy Body?
Lewy bodies are named for Dr. Friederich Lewy, a German neurologist. In 1912, he discovered abnormal protein deposits that disrupt the brain’s normal functioning in people with Parkinson’s disease.
Lewy bodies are formed from a protein called alpha-synuclein. In a healthy brain, alpha-synuclein helps transmit information and communications between nerve cells.
However, in LBD, alpha-synuclein forms into clumps inside the neurons. This starts in areas of the brain that control memory and movement. Alpha-synuclein clumping causes neurons to work less effectively and, eventually, they die. Certain brain chemicals that help transmit messages between nerve cells also become ineffective. The result is widespread damage to specific brain regions and a decline in learning, memory, motor movement, and cognition.
Lewy bodies affect several different brain regions:
- The cerebral cortex, which controls information processing, perception, thought, and language
- The limbic cortex, which plays a major role in emotions and behavior
- hippocampus, is essential to forming new memories
- midbrain and basal ganglia, control movement
- The brain stem, regulating sleep and maintaining alertness
- Brain regions important in recognizing smells (olfactory pathways)
Lewy Body Dementia: Statistics
LBD affects more than 1 million individuals in the United States. It typically begins at age 50 or older, although sometimes younger people have it. It appears to affect slightly more men than women.
This dementia is a progressive disease, meaning symptoms start slowly and worsen over time. The disease lasts an average of 5 to 8 years from the time of diagnosis to death. The time span can range from 2 to 20 years.
How quickly symptoms develop varies from person to person, depending on overall health, age, and severity of symptoms.
In the early stages of LBD, symptoms can be mild, and people can function fairly normally. As the disease advances, people require more help due to a decline in thinking and movement abilities. In the later stages of the disease, they often depend entirely on others for assistance and care.
Some Lewy body dementia symptoms may respond to treatment for a period of time. Currently, there is no cure for the disease.
Research is improving our understanding of this disease, and advances in science may one day lead to better diagnosis, improved care, and new treatments.