What is Lewy body dementia (LBD)?

Updated: Dec 23, 2019
  • Author: Thomas J Montine, MD, PhD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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Lewy body dementia (LBD) refers to pathologic changes that underlie several closely related syndromes. Most manifest with a movement disorder component, and the clinical diagnosis received in life often depends on the interval between the diagnosis of dementia and the onset of movement disorder symptoms. If a clinical diagnosis of Parkinson disease is followed by dementia a minimum of 1 year later, then a diagnosis of Parkinson disease dementia is assigned. [19] If the onset of dementia precedes or is roughly concurrent with the onset of Parkinson disease, then the clinical diagnosis of dementia with Lewy bodies (not to be confused with LBD) is used.

By the time the postmortem diagnosis of LBD can be confirmed, years would have passed since the initial clinical diagnosis, making Parkinson disease dementia and LBD difficult to distinguish. Most LBDs are sporadic and are frequently associated with increased age and the male sex. Organophosphate pesticide exposure is a known risk factor. Of interest, several lines of evidence suggest that a history of cigarette smoking may protect from the processes that lead to LBD.

LBD and Parkinson disease dementia share characteristic neuropathologic changes, such as "deposition of alpha-synuclein in Lewy bodies and neurites, and loss of tegmental dopamine cell populations and basal forebrain cholinergic populations." [19]

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