A Convenient Prognostic Tool and Staging System for Progressive Supranuclear Palsy

Background: Progressive supranuclear palsy (PSP) causes major disability, shortens life, and as yet has no disease-modifying and little symptomatic treatment. A convenient prognostic tool is needed to assist patients, families, and clinicians in planning care. Objectives: We calculated times to acquisition of certain disease milestones and death. Methods We followed a cohort of 417 patients with PSP-Richardson syndrome from 1995 to 2016, applying the Progressive Supranuclear Palsy Rating Scale (PSPRS) at each visit. We generated median times to acquisition of 13 milestones using the input variables of sex, onset age, rate of disease progression from motor symptom onset to initial visit, and PSPRS score at the baseline. Of the outcome milestones, 5 were stages of a new, provisional PSP staging system. The other 8 milestones comprised death and disabling levels of cognitive loss, gaze palsy, dysarthria, dysphagia, and gait/balance impairment. Results: We derived median times to milestones, with 25th and 75th percentiles and 95% confidence intervals of the median for baseline PSPRS scores from 25 to 65 (scale range, 0-100). Sex and initial progression velocity significantly influenced the death milestone, but not most of the others. Median time to death ranged from 4.8 years for a man with PSPRS score of 25 and a slow progression velocity from onset to initial visit of 0.51 PSPRS points/month to 1.8 years for a woman with PSPRS 65 and rapid initial velocity of 2.25 points/month. Conclusions: We have created a convenient, inexpensive, noninvasive reference for counseling patients with PSP-Richardson syndrome on approximate time to encountering 13 life-altering disease milestones.