Remote Online-Based Application of the Cerebellar Cognitive Affective Syndrome Scale

The Cerebellar Cognitive Affective Syndrome Scale (CCAS-S) is increasingly used in clinical trials to assess non-motor function in cerebellar disorders, yet its suitability for remote administration has not been evaluated. Using a matched-pairs design, we compared remote, video-based administration of the German CCAS-S (version A) in 22 patients with cerebellar disease and 22 matched controls with at site -testing from a larger, previously tested cohort. Group matching included age, level of education, sex, occupational experience, and ataxia severity. Uncorrected as well as age, education and sex corrected CCAS-S scores were analysed. Test-retest and interrater reliability were assessed in subsets of the remote cohort. Remotely tested patients did not perform worse than at site tested patients regarding the number of failed test items or the total sum raw score. Instead, fewer significant group differences on single test items emerged in the remote cohort between patients and controls compared to the at site tested cohort. Test-retest reliability of remote CCAS-S administration was good in patients and in controls, and interrater reliability was good to excellent. The coefficients were of a similar magnitude as the published values for at site administration, but were not compared statistically because of differences in study design and small subgroup sizes. Remote administration of the CCAS-S is feasible and shows good test-retest and interrater reliability. However, the present cohort-comparison design does not permit conclusions regarding measurement equivalence between remote and at site administration. Until equivalence has been established in a within-subject crossover design, remote and at site CCAS-S data should not be pooled, and remotely assessed patients should be compared against remotely assessed controls.