Table 1

The latest diagnostic criteria for dementia with Lewy bodies (DLB)

Diagnostic criteria
For a patient with dementia (defined as a progressive cognitive decline of sufficient magnitude to interfere with normal social or occupational functions or with activities of daily living):
  1. A ‘probable’ DLB diagnosis requires at least two core features or one core feature and at least one indicative biomarker, whereas

  2. a ‘possible’ DLB diagnosis requires only one of the seven from the list of core features or indicative biomarkers.

Supportive biomarkers are helpful in making the diagnosis, but their specificity to DLB is not clear.
In addition, a patient must have either developed dementia before, or within 1 year, of the onset of any parkinsonian symptoms; hence, if more than a year passes before the onset of dementia following parkinsonism, the alternative diagnosis of Parkinson’s disease dementia (PDD) is made.
Core featuresIndicative biomarkersSupportive biomarkers
  1. recurrent visual hallucinations

  2. fluctuating cognition

  3. spontaneous features of parkinsonism

  4. rapid eye movement (REM) sleep behaviour disorder (RBD).

  1. polysomnography confirming RBD by showing REM sleep without atonia

  2. abnormal dopamine transporter (DAT) imaging revealing reduced DAT uptake in the basal ganglia

  3. 123Iodine-metaiodobenzylguanidine myocardial scintigraphy revealing loss of postganglionic sympathetic cardiac innervation.

  1. relative preservation of medial temporal lobe structures on CT or MRI

  2. generalised low uptake on single-photon emission CT/positron emission tomography (PET) perfusion/metabolism scan with reduced occipital activity±posterior cingulate island sign on fluorodeoxyglucose PET imaging

  3. prominent posterior slow-wave activity on EEG with periodic fluctuations in the prealpha/theta range.