MAPT and Alzheimer disease: Unlike patients with VH in the context of PD with dementia, patients with VH, PD and relative preservation of cognition do not have prominent cortical or hippocampal LB involvement.20 VH are also linked to higher amyloid and tau pathology in frontal, parietal and hippocampal areas,21 and patients with PD who go on to develop VH have cerebrospinal fluid (CSF) amyloid changes that suggest early AD pathology.22 In PD without dementia, the occipital lobe is relatively free of pathology with absent LB and tau pathology and mild amyloid burden irrespective of whether patients experience VH.23