What Lewy Body Disease Is
On this page:
- Lewy body disease is a kind of dementia
- What are Lewy bodies?
- Symptoms of Lewy body disease
- Why do some people get Lewy body disease?
- For more information
Lewy body disease is a kind of dementia. Dementia is a general decline in cognitive abilities (thinking, memory, language, etc.) usually due to degeneration of the brain. There are many kinds of dementia. The most common and best known kind is Alzheimer's disease. Lewy body disease is thought to be the second most common kind of dementia. It causes cognitive problems similar to those seen in Alzheimer's disease and motor problems like those in Parkinson's. Like Alzheimer's disease, Lewy body disease is currently incurable and it gets worse with time. It should be noted that there are some kinds of dementia (for example, those caused by a thyroid problem or a deficiency in vitamin B-12) that can be reversed. That's why it's important to have a full work-up done when dementia is suspected.
Lewy body disease is also referred to as dementia with Lewy bodies, Lewy body dementia, diffuse Lewy body disease, senile dementia of Lewy body type, and Lewy body variant of Alzheimer's disease.
Despite its prevalence, Lewy body disease is not well known. Every year, it seems that Newsweek and other popular magazines run a feature article on the progress made against Alzheimer's disease, and any new information about Alzheimer's is big news. In these articles there's never a mention of Lewy body disease. In our experience many health professionals (physical therapists, nurses, and even some doctors) aren't well informed about Lewy body disease.
In 1912, while Frederick Lewy was examining the brains of people with Parkinson's disease, he discovered irregularities in the cells in the mid-brain region. These abnormal structures (microscopic protein deposits found in deteriorating nerve cells) became known as Lewy bodies. Since that time, the presence of Lewy bodies in the mid-brain has been recognized as a hallmark of Parkinson's disease. In the 1960s, researchers found Lewy bodies in the cortex (the outer layer of gray matter) of the brains of some people who had dementia. Lewy bodies in the cortex are known as cortical Lewy bodies or diffuse Lewy bodies. (That's why Lewy body disease is sometimes called cortical Lewy body disease or diffuse Lewy body disease.) Cortical Lewy bodies were thought to be rare, until the 1980s when improved methodologies showed that Lewy body disease was more common than previously realized.
People with Lewy body disease have Lewy bodies in the mid-brain region (like those with Parkinson's disease) and in the cortex of the brain. It's believed that they usually also have the "plaques and tangles" of the brain that characterize Alzheimer's disease. Conversely, it's believed that many people with Alzheimer's disease also have cortical Lewy bodies. Because of the overlap, it's likely that many people with Lewy body disease are misdiagnosed (at least initially) as having either Parkinson's disease or Alzheimer's disease. A big factor in the misdiagnosis might be that Lewy body disease is relatively unknown.
People with Lewy body disease have cognitive problems (problems with thinking, memory, language, etc.) similar to those that occur in Alzheimer's disease. Therefore, it can be hard to distinguish the two. Some doctors think there are three distinguishing features and the presence of two of them makes the diagnosis of Lewy body disease probable:
- Motor problems typical of Parkinson's disease but usually not so severe as to warrant a diagnosis of Parkinson's. Of these problems, an impairment in walking (a shuffling gait) might be the most common one. Also common would be muscle stiffness and a tendency to fall. Tremor would be less common.
- Fluctuations in cognitive function with varying levels of alertness and attention. Periods of being alert and coherent alternate with periods of being confused and unresponsive to questions.
- Visual hallucinations, usually occurring early on. Delusions may be common too.
It's possible that people with Lewy body disease are better able to form new memories than those with Alzheimer's disease. Compared with Alzheimer's, Lewy body disease may affect speed of thinking, attention and concentration, and visual-spatial abilities more severely than memory and language. Depression may be a typical symptom too.
Right now, doctors prescribe drugs to treat four major features found in Lewy body disease (also see the medication section of our Information page):
- Cognitive problems. Usually, a drug like Aricept is prescribed. This is the same drug that is commonly prescribed for Alzheimer's disease. In some people, it seems to slow the progression of the disease.
- Motor problems. Levodopa/carbidopa (Sinemet) is frequently prescribed to deal with the motor problems. This medication can worsen hallucinations, though.
- Hallucinations. An antipsychotic medication, such as Zyprexa, might be prescribed. This kind of medication can worsen motor problems, though. Also note the FDA warning.
- Depression. In cases of depression, an antidepressant, such as Zoloft or Prozac, might be prescribed.
No one knows.