Lewy body dementia is a less common form of dementia and can easily be misdiagnosed as Alzheimer's disease, because the symptoms are similar. Unlike those with Alzheimer's, individuals with Lewy body dementia also tend to see and hear things that are not there, early in the course of the dementia. Although the inital flucuating impairment may be mild, individuals with Lewy body eventually develop severe and constant dementia. There is neither a cure or a method to reverse the symptoms. There is only symptomatic treatment.
Diagnosis is clinical, related to course.
The only way to tell for sure is an autopsy, the brainstem of the affected individual will be freckled with Lewy bodies, just as the brainstem of a person with Parkinson's disease. In addition, Lewy bodies are found in the cortex, along with some of of the characteristic lesions found in Alhzeimer's disease. I hope that this is of some help to you. My mother was diagnosed with Lewy body 18 months ago and has deteriorated rapidly. The doctor said that the treatment of the symptoms depends on the individual and that what help one may not help another.