The Japanese Version of the Brief Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis: A Preliminary Validation

BACKGROUND: Cognitive impairment is a common and disabling symptom in multiple sclerosis (MS). OBJECTIVE: To examine the reliability and validity of the Japanese version of the Brief Repeatable Battery of Neuropsychological Tests (BRB‑N) and develop individualized classification thresholds for detecting cognitive impairment in MS. METHOD: Twenty‑two individuals with MS and 43 healthy controls completed the BRB‑N. We assessed internal consistency using Cronbach's α. Discriminative ability was evaluated with receiver operating characteristic analyses and Bayesian logistic regression adjusted for age, sex, and education. We derived classification thresholds using the Youden Index. Frequentist logistic regression served as a sensitivity analysis. Finally, we assessed parallel-form reliability by comparing versions A and B of the BRB-N in healthy controls using the Wilcoxon signed-rank test. RESULTS: The Japanese BRB‑N demonstrated acceptable internal consistency (Cronbach's α = 0.78) and stable model convergence (R‑hat ≤ 1.01, ESS ≥ 400). All measures achieved an area under the curve of ≥0.70, with scores on the Paced Auditory Serial Addition Test 2 and 3 and the Symbol Digit Modalities Test showing the highest values (0.92, 0.92, and 0.87, respectively). Eight of 13 measures showed strong effects, with 95% highest posterior density intervals excluding 1 and posterior probabilities exceeding 95%. Frequentist analyses yielded consistent patterns. Parallel‑form comparisons between versions A and B showed no significant differences. A computational tool for individualized threshold estimation was developed. CONCLUSION: These preliminary findings support the reliability and potential clinical utility of the Japanese BRB‑N for MS.