Lewy body dementia, or LBS, affects 1.4 million million people in the United States, usually after the age of 50. It is frequently misdiagnosed, largely due to the fact that its symptoms often mimic those of other more commonly known diseases, such as Alzheimer’s and Parkinson’s. There are still a good number of medical professionals that are not familiar with LBD. LBD, a progressive degenerative dementia, primarily affects older adults. It is the second most frequent cause of hospitalization for dementia, after Alzheimer’s disease. LBD is diagnosed when cognitive symptoms begin at the same time or within a year of Parkinson symptoms, and is characterized by an abnormal buildup of Lewy bodies (alpha-synuclein protein deposits) in the areas of the brain that regulate memory, behavior, personality, and movement. In Parkinson's disease, the most prominent symptoms affect motor abilities. While there are many different causes for dementia, the term Alzheimer's is frequently used to describe all dementias. To help with the distinction between the two, LBDA has issued a brochure Lewy Who? Recognizing when it's not Parkinson's or Alzheimer's Disease-- that offers a symptom comparison chart that can help clarify the confusion. It can be downloaded from the LBDA.org website.
Weintraub, Daniel; Hurtig, Howard I. (2007), "Presentation and Management of Psychosis in Parkinson's Disease and Dementia with Lewy Bodies", American Journal of Psychiatry 164 (10): 1491–1498, doi:10.1176/appi.ajp.2007.07040715, PMC 2137166, PMID 17898337