Validation of the cerebellar cognitive affective syndrome (CCAS) scale in CCAS patients and cerebellar controls

Abstract

OBJECTIVE: The cerebellar cognitive affective syndrome (CCAS) scale has been developed to screen for possible cognitive and affective impairments in cerebellar patients, but previous studies stressed concerns regarding insufficient specificity of the scale. Also, direct comparisons of CCAS scale performance between cerebellar patients with and without CCAS are currently lacking. The aim of this study was to evaluate the validity of the CCAS scale in cerebellar patients. METHOD: In this study, cerebellar patients with CCAS (n = 49), without CCAS (n = 30), and healthy controls (n = 32) were included. The Dutch/Flemish version of the CCAS scale was evaluated in terms of validity and reliability using an extensive neuropsychological assessment as the gold standard for CCAS. Correlations were examined between the CCAS scale and possible confounding factors. Additionally, a correction for dysarthria was applied to timed neuropsychological tests to explore the influence of dysarthria on test outcomes. RESULTS: Cerebellar patients with CCAS performed significantly worse on the CCAS scale compared to cerebellar controls. Sensitivity was acceptable, but specificity was insufficient due to high false-positive rates. Correlations were found between outcomes of the scale and both education and age. Although dysarthria did not affect the validity of the CCAS scale, it may influence timed neuropsychological test outcomes. CONCLUSIONS: Evaluation of the CCAS scale revealed insufficient specificity. Our findings call for age- and education-dependent reference values, which may improve the validity and usability of the scale. Dysarthria might be a confounding factor in timed test items and should be considered to prevent misclassification.