When were Lewy bodies first described and how has understanding of dementia with Lewy bodies (DLB) evolved over time?

Updated: Aug 08, 2019
  • Author: Howard A Crystal, MD; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Answer

Dementia with Lewy bodies (DLB) is a progressive, degenerative dementia. Frederick Lewy first described Lewy bodies (LBs)—cytoplasmic inclusions found in cells of the substantia nigra in patients with idiopathic Parkinson disease —in 1914. (See Etiology.)

In the 1960s, several pathologists described patients with dementia who had LBs of the neocortex. However, such cases were presumed to be rare until the mid-1980s, when sensitive immunocytochemical methods to identify LBs were developed. DLB was then recognized as being far more common than previously thought. (See Workup.)

The relationship of DLB and Parkinson disease is an area of considerable controversy, particularly because dementia frequently occurs in Parkinson disease. Many investigators believe that a spectrum of LB disorders exists.

Clinical criteria for DLB were first proposed in 1996 [2] and modified in the subsequent DLB Consortium reports. [3] Several clinicopathologic studies have assessed the sensitivity and specificity of these clinical criteria. (See Presentation and Workup.) [4, 5]

The third report of the DLB Consortium, headed by Ian McKeith, discussed an arbitrary 1-year rule to distinguish DLB from Parkinson disease with dementia. [6] According to the report, if parkinsonism has been present for 12 months or longer before cognitive impairment is detected, the disorder is called Parkinson disease with dementia; otherwise, it is called DLB. The report recognized that this rule may be difficult to apply in clinical practice. When dementia precedes motor signs, particularly with visual hallucinations and episodes of reduced responsiveness, the diagnosis of DLB should be considered. (See Presentation.)


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