Medical Edge Newspaper Column

Similarities, Differences Between Lewy Body Dementia And Parkinson's

March 20, 2008
Dear Mayo Clinic:
What can you tell me about Lewy body dementia? What treatments are most effective, if any? Also, how does it mimic Parkinson's?

Answer:
A progressive brain disease, Lewy body dementia is caused by abnormal protein deposits found in degenerating nerve cells. These protein deposits (called Lewy bodies after the physician who first identified them) are also found in people who have Parkinson's disease. In Parkinson's, Lewy bodies occur most frequently in the deep structures of the brain that control movement. In Lewy body dementia, they are found in the deep structures, as well as in the middle and outer structures that are involved in emotion, behavior, judgment and awareness.

Because Lewy bodies are distributed throughout the brain, people with Lewy body dementia usually have some symptoms generally associated with Parkinson's, called parkinsonism — such as stooped posture, a shuffling gait, slow movement and difficulty with fine motor skills. They also usually have some symptoms associated with Alzheimer's disease — such as confusion and problems with judgment, problem-solving and decision-making. In some cases, Lewy body dementia may affect memory, but not always. The defining symptoms of the disease include a decline in mental abilities (dementia), fluctuating attention and alertness, vivid visual hallucinations and parkinsonism.

Lewy body dementia usually progresses slowly over several years, but the way it progresses can vary significantly from person to person. For example, it may begin with signs of dementia, with parkinsonism appearing later. Or, the disease may start with movement difficulties, and signs of dementia don't emerge for some time. Most people with Lewy body dementia experience the onset of parkinsonism and the onset of dementia within one to two years of each other, although some never develop any features of parkinsonism. As the disease progresses, all symptoms usually become more severe.

Currently, there's no cure, and no specific therapy can stop the disease progression. However, symptoms often can be controlled to improve a person's daily functioning and quality of life.

Some people diagnosed with Lewy body dementia respond positively to drugs approved for treating Alzheimer's. These drugs, called cholinesterase inhibitors, boost the level of a chemical messenger in the brain (acetylcholine) that's important for memory and other cognitive functions. They may help improve alertness and reduce hallucinations and signs of dementia. Several other medications also are available to help decrease the parkinsonism, hallucinations and fluctuations of the disease. These medications must be carefully monitored by a health care provider. In people who have Lewy body dementia, medications to improve motor function may make symptoms such as hallucinations worse, and medications used to combat dementia may increase parkinsonism.

Because treatment needs to be carefully managed to obtain the most effective results, people who have this disease should be closely monitored by a physician with expertise and experience with Lewy body dementia, which may include a neurologist, neuropsychiatrist, or geriatric psychiatrist.

— Bradley Boeve, M.D., Neurology, Mayo Clinic, Rochester, Minn.