Hypothetical algorithm for the identification of prodromal Lewy body disease. The first stage consists of assessment for simple markers of functional decline – symptom questionnaires, cognitive tests and simple clinical biomarkers (for example, biomarkers for hyposmia). In the second stage, those with a profile suggestive of Lewy body (LB) disease would undergo tests with greater specificity, identifying death or dysfunction of cell groups affected by LB pathology, or the presence of alpha-synuclein (αSyn) pathology. This may include cardiac metaiodobenzylguanidine (MIBG) scintigraphy, measures of substantia nigra pathology, such as ultrasound or striatal dopamine transporter imaging, or biopsy for the presence of αSyn. FP-CIT, N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane; MCI, mild cognitive impairment.