Rasch Analysis of the Chinese Version of the Nociception Coma Scale–Revised in Patients with Prolonged Disorders of Consciousness

Abstract

Objectives The aim of this study was to analyze the Chinese version of the Nociception Coma Scale–Revised in patients with prolonged disorders of consciousness within the framework of Rasch modeling, including investigating the invariance of total scores across different etiologies of disorders of consciousness. Design Prospective psychometric study. Participants Patients with prolonged disorders of consciousness from the Rehabilitation and Neurology units in hospital. Interventions None. Main Outcome Measure The Nociception Coma Scale–Revised was undertaken by trained raters and the Coma Recovery Scale-Revised was used to assess patients’ consciousness. The psychometric properties within the Rasch model including item-person targeting, reliability and separation, item fit, unidimensionality, and differential item functioning were assessed. Results 84 patients with prolonged disorders of consciousness (mean age 53 years; mean injury 5 months; 42 with Minimally Conscious State and 42 with Unresponsive Wakefulness Syndrome) of 252 observations were enrolled in the study. Through the procedure of repeated assessment and differential item function, a lower item bias Rasch set was purified. The Rasch model assumptions were examined and met, with item reliability and validity meeting the recommended threshold. Conclusions The Chinese version of the Nociception Coma Scale–Revised demonstrated unidimensionality, good reliability and separation, and good item fit, but dissatisfied person fit and item-person targeting. The verbal subscale showed a notable discrepancy between person responses and the difficulty of the items, suggesting limited clinical significance.