MAPT and supranuclear palsy, progressive, 1: A probabilistic data-driven modelling approach (event-based modelling) has been used to characterise the in-vivo sequence of brain atrophy in PSP-RS,25 where the order of regional atrophy broadly mirrors the sequential spread of tau pathology proposed by Kovacs et al. 3 However, the event-based modelling assumes sample homogeneity, making it unsuitable to investigate the full spectrum of PSP phenotype heterogeneity.