Association of Progressive Supranuclear Palsy Rating Scale with Progressive Supranuclear Palsy Quality of Life Scale

Introduction: There is growing interest in using patient-reported outcomes as end points in clinical trials, such as the progressive supranuclear palsy quality of life (PSP-QoL) scale. However, this tool has not been widely validated and its correlation with validated motor scales has not been explored. To evaluate the potential utility of using PSP-QoL as an outcome, it is important to examine its relationship with a standard scale used to evaluate neurologic parameters, such as the PSP Rating Scale. Methods: PSP-QoL and PSP Rating Scale scores were gathered from 60 clinically diagnosed PSP patients, including patients with Richardson syndrome PSP (PSP-RS, n = 43) and those with non-RS PSP variants (n = 17). Linear regression analysis adjusted for age, sex, and disease duration was used to evaluate the cross-sectional relationship between the total and subscale scores of the 2 instruments. Results: Among 60 PSP patients, there was a significant correlation between total PSP-QoL and PSP Rating Scale scores. The physical and mentation subscales of each instrument also demonstrated significant correlations. Comparisons among PSP subtypes indicated that worsening PSP-QoL Total and Physical subscale scores correlated with worsening PSP Rating Scale gait subscale scores more strongly for the non-RS PSP variants than for PSP-RS. Discussion: There is a significant association between the total scores and many of the subscale scores of the PSP-QoL and the PSP Rating Scale. Additionally, the relationship between these measures may differ for PSP-RS and non-RS variants. These findings suggest that the PSP-QoL may be useful in clinical trials as a patient-reported outcome measure. Large prospective multicenter studies utilizing the PSP-QoL are necessary to examine its relationship to disease evolution and changes in the PSP Rating Scale.