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

Progressive supranuclear palsy (PSP) is a rare and devastating tauopathy with limited global data. Given India's large population, genetic diversity, and clinical heterogeneity, large multicenter datasets are crucial to enrich global understanding of PSP.

To characterize the demographic, clinical, and phenotypic profiles of a large multicenter Indian PSP cohort.

Subjects fulfilling MDS-PSP criteria were prospectively recruited across movement disorders centers (2021-2025). Standardized demographic and clinical data were collected.

A total of 1035 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-Richardson's 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) indicating progression patterns. 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.

This 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.