Utility of the Weighted APE2SM Score for Diagnosing Autoimmune Encephalitis: Comparison with APE2 and Graus Criteria
Bijoya Basu1, Sophia Damman1, Samhitha Rai1, Hesham Abboud2
1Case Western Reserve University School of Medicine, 2University Hospitals Cleveland Medical Center
Objective:
To evaluate the diagnostic performance of an exploratory modified score (APE2SM) incorporating seizure and movement disorder weighting for autoimmune encephalitis (AE), and to compare its performance with the APE2 score and Graus criteria.
Background:
Diagnosis of AE, particularly in antibody-negative cases, remains challenging and relies on clinical criteria and supportive investigations. The APE2 score provides a quantitative framework for risk stratification but may underweight key clinical features such as seizures and movement presentations. We developed and assessed the APE2SM score to address this limitation.
Design/Methods:
We conducted a retrospective study of consecutive patients referred for suspected AE (January 2017–May 2023). Final diagnosis was determined by expert consensus based on clinical features, exclusion of alternative diagnoses, and response to immunotherapy. APE2, Graus criteria, and APE2SM scores were assigned retrospectively. The APE2SM score weights movement disorders and seizure presentations more heavily compared to the APE2 score. Diagnostic performance was assessed using receiver operating characteristic analysis, contingency tables, and logistic regression to model probability of AE across score thresholds.
Results:
Eighty-five patients were included (56.5% female; mean age 53.8 years), of whom 59 (69.4%) had AE, including 34 antibody-positive cases. In exploratory analyses, APE2SM demonstrated the strongest overall diagnostic performance, with comparable discrimination to APE2 but improved sensitivity and negative predictive value, particularly at clinically relevant thresholds and in antibody-negative patients. APE2 outperformed Graus criteria in the full cohort (AUC 0.894 vs 0.804) and in antibody-negative patients (AUC 0.905 vs 0.850). An APE2 cutoff ≥4 achieved balanced sensitivity and specificity near or above 80%, whereas no Graus threshold achieved similar balance.
Conclusions:
The exploratory APE2SM score improves sensitivity while maintaining acceptable specificity and may enhance early recognition of AE, particularly in antibody-negative cases. These findings support further prospective validation. APE2 remains a robust and practical screening tool with a clinically useful cutoff of ≥4.
Generative AI Usage
No, did not use generative AI in the drafting or editing in this abstract.
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