Table 1 Revised criteria for the clinical diagnosis of DLB (2005)

1. Central feature (essential for a diagnosis of possible or probable DLB)

Dementia defined as progressive cognitive decline of sufficient magnitude to interfere with normal social or occupational function.

2. Core features (two core features are sufficient for a diagnosis of probable DLB, and one for possible DLB)

Fluctuating cognition with pronounced variations in attention and alertness

Recurrent visual hallucinations that are typically well formed and detailed

Spontaneous features of parkinsonism

3. Suggestive features

REM sleep behaviour disorder

Severe neuroleptic sensitivity

Low dopamine transporter uptake in basal ganglia demonstrated by SPECT or PET imaging.

4. Supportive features

Repeated falls and syncope

Transient, unexplained loss of consciousness

Severe autonomic dysfunction, e.g., orthostatic hypotension, urinary incontinence

Hallucinations in other modalities

Systematised delusions

Depression

Relative preservation of medial temporal lobe structures on CT/MRI scan

Generalised low uptake on SPECT/PET perfusion scan with reduced occipital activity

Abnormal (low uptake) MIBG myocardial scintigraphy

Prominent slow wave activity on EEG with temporal lobe transient sharp waves

5. A diagnosis of DLB is less likely

In the presence of cerebrovascular disease evident as focal neurologic signs or on brain imaging

In the presence of any other physical illness or brain disorder sufficient to account in part or in total for the clinical picture

If parkinsonism only appears for the first time at a stage of severe dementia

6. Temporal sequence of symptoms

DLB should be diagnosed when dementia occurs concurrently or within one year of parkinsonism (if it is present).