The Progressive Supranuclear Palsy Rating Scale Identifies Early Motor Symptoms in Primary Progressive Aphasia

Abstract Objective This study examined cross-sectional differences in Progressive Supranuclear Palsy Rating Scale (PSPRS) scores among participants with behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA). We hypothesized that participants with nonfluent/agrammatic PPA (nfPPA) will show the highest (worst) PSPRS scores and greater gray matter atrophy in regions associated with progressive supranuclear palsy (PSP) pathology. Method Participants were enrolled in the ARTFL LEFFTDS Longitudinal Frontotemporal Lobar Degeneration consortium (ALLFTD). Analyses were limited to first visit data. Ten anatomic regions of interest were pre-selected for analysis based on previously identified neuroanatomic correlates of PSPRS performance. Differences in participant characteristics and clinical outcomes were compared using pairwise comparison of means. Linear multivariable regression adjusting for age and total intracranial volume was used to examine associations between regional gray matter volumes and diagnosis. The analyses were stratified by disease severity. Results Participants with early-stage nfPPA had higher total PSPRS scores compared to those with bvFTD or semantic dementia (SD) and performed more poorly on domains of dysphagia, fine motor movements, falls, postural stability, dysarthria, saccadic eye movements, and motor rigidity. Participants with advanced-stage nfPPA showed greater atrophy in the left putamen, supplementary motor area, and precentral gyrus than those with bvFTD. Conclusion Our study highlights the phenotypic complexity of PPA and the utility of the PSPRS in capturing early motor symptoms in nfPPA. These data suggest that the PSPRS may facilitate early intervention in identifying and facilitating treatment of early motor symptoms, decreasing disability and improving quality of life in PPA.