The Dementia with Lewy Bodies (DLB) Consortium has refined its recommendations on the diagnosis of DLB.
The new guidelines, published in Neurology , distinguish clearly between clinical features and diagnostic biomarkers of DLB, and give recommendations on the interpretation of diagnostic findings.
According to the guidelines, probable DLB can be diagnosed when two or more core clinical features are present, with or without the presence of indicative biomarkers. Core features are identified as the presence of REM sleep behaviour disorder; fluctuating cognition with pronounced variations in attention and alertness; recurrent visual hallucinations; and at least one spontaneous cardinal features of parkinsonism, namely bradykinesia, rest tremor, or rigidity.
Probable DLB can also be diagnosed where one core clinical feature is present, but with one or more indicative biomarker including: reduced dopamine transporter uptake in basal ganglia demonstrated by SPECT or PET; abnormal (low uptake) 123-iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy; or polysomnographic confirmation of REM sleep without atonia. The recommendations state probable DLB should not be diagnosed on the basis of biomarkers alone.
DLB is less likely, the guidelines state, if parkinsonian features are the only core clinical feature and appear for the first time at a stage of severe dementia.