Research criteria for the diagnosis of prodromal dementia with Lewy bodies

Abstract

The prodromal phase of dementia with Lewy bodies (DLB) includes (1) mild cognitive impairment (MCI), (2) delirium-onset, and (3) psychiatric-onset presentations. The purpose of our review is to determine whether there is sufficient information yet available to justify development of diagnostic criteria for each of these. Our goal is to achieve evidence-based recommendations for the recognition of DLB at a predementia, symptomatic stage. We propose operationalized diagnostic criteria for probable and possible mild cognitive impairment with Lewy bodies, which are intended for use in research settings pending validation for use in clinical practice. They are compatible with current criteria for other prodromal neurodegenerative disorders including Alzheimer and Parkinson disease. Although there is still insufficient evidence to propose formal criteria for delirium-onset and psychiatric-onset presentations of DLB, we feel that it is important to characterize them, raising the index of diagnostic suspicion and prioritizing them for further investigation.

Figure. Multimodal biomarkers for prodromal DLB

Reduced dopamine transporter uptake in basal ganglia demonstrated by SPECT or PET; PSG-confirmed REM sleep without atonia and MIBG myocardial scintigraphy are proposed as biomarkers of prodromal DLB. Multimodality biomarkers are also important in characterizing patients with prodromal DLB, in whom the pathologic mechanisms of cognitive impairment include both LB and AD pathologies and who may have abnormalities associated with both. Medial temporal lobe uptake on tau PET, medial temporal lobe atrophy on MRI, and high levels of uptake on amyloid PET and positive CSF biomarkers of AD-related pathology may characterize patients with prodromal DLB with significant AD pathology. It is expected that biomarker abnormalities detected in the earliest stages will remain abnormal as disease progresses, with additional biomarkers showing changes later during the progression from prodromal to dementia phase DLB. DLB = dementia with Lewy bodies; MIBG = meta-iodobenzylguanidine.