Background: Assessing disease severity can be performed using either clinician-rated scales (CRS) or patient-rated outcome (PRO) tools. These two measures frequently demonstrate poor correlations.
Objectives: To determine if the correlation between a CRS and PRO for motor features of cervical dystonia (CD) improves by accounting for non-motor features.
Methods: Subjects with CD (N = 209) were evaluated using a CRS (Toronto Western Spasmodic Torticollis Rating Scale, TWSTRS) and a PRO (Cervical Dystonia Impact Profile, CDIP-58).
Results: Linear regression revealed a weak correlation between the two measures, even when considering only the motor subscales of each. The strength of this relationship improved with a regression model that included non-motor symptoms of pain, depression, and disability.
Conclusions: These results argue that the results of motor assessments in a PRO for CD cannot be fully appreciated without simultaneous assessment of non-motor co-morbidities. This conclusion might apply to other disorders, especially those with frequent non-motor co-morbidities.
Keywords: anxiety; cervical dystonia; depression; dystonia; patient‐reported outcome measure; rating scale; torticollis.
© 2023 International Parkinson and Movement Disorder Society.