MAPT and Parkinson disease: Amyloid deposition has been associated with greater Lewy body pathology in Lewy body disease (Parkinson's disease and Lewy body dementia).44 Preclinical models have shown that the presence of tau promotes the fibrillization of α‐synuclein45 and that the presence of α‐synuclein increases the deposition of tau and amyloid in transgenic mice.46 Combined tau and amyloid imaging studies may help to clarify the contributions of each pathology to atrophy in DLB, although in the absence of an α‐synuclein imaging ligand the contribution of synergistic effects may be difficult to determine.