Lewy body dementia, the second most common type of progressive dementia after Alzheimer’s disease, causes a progressive decline in mental abilities. (html)
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. (html)
The incidence of the disease is largely unknown. Studies have pointed to over a hundred new cases per 100,000 for those over 65 to estimates less than five new cases per 100,000 over 65 a year.