Takeaway
Magnetic Resonance Parkinsonism Index (MRPI) 2.0 may be used as a primary outcome measure in clinical trials in progressive supranuclear palsy (PSP).
Studies aiming to detect ≥20% treatment efficacy can potentially be performed over 2 years in progressive supranuclear palsy-Richardson syndrome (PSP-RS) and PSP-Parkinsonism (PSP-P) with a relatively small number of patients per treatment arm.
Why this matters
In recent years, MRPI has emerged as a highly accurate means of discriminating PSP from Parkinson’s disease (PD) or other parkinsonisms, as well as a way of predicting clinical evolution towards PSP phenotypes.
The investigations outlined in this study may impact future clinical trials in PSP-RS and PSP-P as the results suggest that MRPI 2.0 may be used as a primary outcome measure and inform on the optimal sample size for clinical trials.