How is dementia with Lewy bodies (DLB) clinically distinguished from Alzheimer disease?

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

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

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!