Dementia With Lewy Bodies Clinical Presentation

Updated: Sep 27, 2017
  • Author: Howard A Crystal, MD; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Presentation

History

Dementia with Lewy bodies (DLB) is a progressive, degenerative dementia.The following clinical features help to distinguish DLB from Alzheimer disease:

Fluctuations in cognitive function with varying levels of alertness and attention - Clues to the presence of fluctuations include excessive daytime drowsiness (if nighttime sleep is adequate) or daytime sleep longer than 2 hours, staring into space for long periods, and episodes of disorganized speech

  • Visual hallucinations
  • Parkinsonian motor features

Although extrapyramidal features may occur late in the course of Alzheimer disease, they appear relatively early in DLB.

In addition, whereas patients with Alzheimer disease virtually always have anterograde memory loss as a prominent symptom and sign early in the course of the illness, anterograde memory loss may be less prominent in DLB. McKeith et al have suggested that patients with DLB do relatively better on tests of confrontation naming, short and medium recall, and recognition than do patients with Alzheimer disease, whereas patients with Alzheimer disease do better on tests of verbal fluency, visual perception, and performance tasks. [11]

Executive function deficits and visuospatial impairment may be more prominent in persons with DLB than in those with Alzheimer disease (eg, Stroop, digit span backwards).

Other symptoms that may alert clinicians to the diagnosis of DLB (versus Alzheimer disease) include the following:

  • Nonvisual hallucinations
  • Delusions
  • Unexplained syncope
  • Rapid eye movement sleep disorder
  • Neuroleptic sensitivity
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Physical Examination

Patients with DLB usually have impaired cognition consistent with dementia. Cognitive function, as measured by Mini-Mental State Examination (MMSE) scores, appears to be relatively preserved in DLB compared with Alzheimer disease (AD) or AD+DLB (P < .01). Nelson et al evaluated data from 2 large, multicenter data registries (6,340 cases in total) and found that final MMSE scores were 15.6 (+/- 8.7) in persons with DLB, 10.7 (+/- 8.6) in persons with Alzheimer disease, and 10.6 (+/- 8.6) in those with AD+DLB. [12]

An important observation during mental status testing is that the patient has periods of being alert, coherent, and oriented that alternate with periods during which the patient is confused and unresponsive to questions (despite the fact that the patient is awake). This fluctuation is a relatively specific feature of DLB.

Retrieval from memory may be relatively worse than memory storage. Patients may do relatively well with confrontation naming tests and poorly on tests of visuospatial skills (eg, drawing a clock, copying figures).

Patients may have some parkinsonian signs but usually not enough to meet the criteria for a diagnosis of Parkinson disease. Mild gait impairment is relatively frequent and should not be ascribed to old age or osteoarthritis. Resting tremor occurs less frequently than in Parkinson disease. Myoclonus may occur before severe dementia.

Orthostatic hypotension appears to be particularly common in patients with DLB, even when dementia is mild. [1]

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