Validation of the Clinical Assessment Scale for Autoimmune Encephalitis: A Multicenter Study.

Introduction: A new scale, named the Clinical Assessment Scale for Autoimmune Encephalitis (CASE), has recently been developed for rating the severity of autoimmune encephalitis (AE) with a high level of clinimetric properties. In this study, our primary objective was to validate the performance of CASE through a multicenter study in China.

Methods: Between July 2014 and December 2019, 143 consecutive patients with definite neuronal surface antibody-associated AE from three tertiary hospitals were enrolled in the study. We validated the reliability, internal consistency, and validity of CASE. We further compared CASE with the modified Rankin scale (mRS) among different subtypes of AE in terms of its sensitivity to disease dynamics. Statistical analyses were performed using GraphPad Prism and R software.

Results: Our analyses showed that CASE had good inter- and intraobserver reliability (intra-class correlation coefficient 0.96/0.98) and internal consistency (Cronbach α = 0.847) at disease onset. The scores of CASE and mRS remained well correlated in patients at admission and at discharge (both r = 0.80, p < 0.001). From admission to discharge, the scores of CASE changed in 81 (56.6%) patients, in comparison to changes in mRS in 48 (33.6%) patients (p = 0.007 and p < 0.001, respectively). The largest changes in scores occurred for non-motor symptoms, including psychiatric, memory, and language dysfunctions (40.6, 26.6, and 23.1% of patients, respectively); in contrast, scores for motor symptoms, such as dyskinesia, weakness and ataxia, changed the least (7.0, 15.4, and 16.1% of patients, respectively).

Conclusion: Based on these results, CASE performed well in assessing the severity of neuronal surface antibody-associated AE. In comparison to mRS, it performed better for non-motor symptoms and was more sensitive to changes in severity.