Progressive Supranuclear Palsy in India: Insights from a Large Multicenter Clinical Cohort (Project PAIR-PSP)

BackgroundProgressive supranuclear palsy (PSP) is a rare and devastating tauopathy with limited global data. Given Indias large population, genetic diversity, and clinical heterogeneity, large multicenter datasets are crucial to enrich global understanding of PSP. ObjectiveTo characterize the demographic, clinical, and phenotypic profiles of a large multicenter Indian PSP cohort. MethodsSubjects fulfilling MDS-PSP criteria were prospectively recruited across movement disorders centers (2021-2025). Standardized demographic and clinical data were collected. ResultsA total of 1,035 subjects were enrolled (M:F = 709:326), with a median age of 65 years and a mean onset age of 62.2{+/-}7.9 years. Regional distribution reflected pan-Indian recruitment (South 35%, North 26%, West 21%, East 18%). PSP-Richardsons syndrome was most common (41%), followed by PSP-Parkinsonism (18%) and PSP-CBS (11%); rarer phenotypes included PSP-PI (7%), PSP-F (7%), PSP-PGF (5%), PSP-OM (2%), PSP-SL (1%), and PSP-C (1%). Falls occurred earliest in PSP-PGF (13.7 months) and PSP-SL (16.3 months), while PSP-P showed delayed disability (falls at 31 months). Cognitive onset was prominent in PSP-F (21%) and PSP-SL (57%). Levodopa was prescribed to 893 patients; 186 (21%) reported >25% subjective benefit, and 358 (40%) reported [≤]25% benefit. Amantadine was used in 351 (34%) patients, with improvement in 177. ConclusionThis largest systematically profiled PSP cohort highlights both shared and distinctive features: high frequency of non-RS variants, aggressive course in PSP-RS/SL, better survival in PSP-P, and limited pharmacological benefit. These findings establish a foundation for longitudinal and genetic studies in diverse populations.