Hypothetical timelines of biomarker development. (A) Biomarker development in dementia with Lewy bodies (DLB). This hypothesis mirrors that proposed by Jack and colleagues in Alzheimer’s disease . The first biomarkers of DLB will be markers of alpha-synuclein (αSyn) deposition (for example, from skin biopsy). αSyn deposition probably decreases later in the disease process following cell death . This would then be followed by markers of cell damage or death (for example, loss of dopamine transporters in the striatum on single photon emission computed tomography or positron emission tomography) and then clinical symptoms/signs (for example, parkinsonism). (B) Biomarkers in two different sites. In this hypothetical representation, αSyn deposition, cell damage and loss and the development of symptoms (hyposmia) all occur in the olfactory bulb prior to the development of αSyn deposition in the neocortex.