Because vascular dementia can cause symptoms and signs similar to those of DLB, brain MRI is indicated to distinguish DLB from vascular dementia. Patients with vascular dementia often have white matter lesions on MRI scans, whereas patients with DLB do not.
CSF examination is not required in routine cases. However, CSF findings in DLB include:
Patients with Alzheimer disease have higher levels of tau protein in their CSF than do patients with DLB
Patients with the Lewy body variant of Alzheimer disease (LBV-AD) have intermediate values
CSF levels of beta amyloid are lower than normal in DLB, Alzheimer disease, and LBV-AD; however, CSF beta-amyloid levels in DLB, LBV-AD, and Alzheimer disease do not differ from each other
Patients with DLB usually have less hippocampal atrophy than do patients with Alzheimer disease (but more than control subjects), although whether this difference is clinically useful is under investigation, as is the diagnostic utility of functional imaging. MRI is superior to CT scanning in identifying this atrophy.
Until disease-modifying therapies that are specific to DLB or Alzheimer disease are developed, metabolic imaging studies to enhance the accuracy of the diagnosis are rarely needed.
For more on the workup of DLB, read here.
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Cite this: Helmi L. Lutsep. Fast Five Quiz: Dementia - Medscape - Oct 17, 2018.