Validating the quality of life after brain injury through rasch analysis

Objective: The Quality of Life after Brain Injury (QOLIBRI), a cross-cultural instrument, has been validated in several languages; however, traditional psychometric approaches have critical limitations. Therefore, we applied the Rasch model for validating the 37-item QOLIBRI scale among a Chinese population with traumatic brain injury. Participants and Setting: In total, 587 participants (mean age: 44.2 ± 15.4 years; women, 46.3%) were surveyed in neurosurgery departments at 6 hospitals in Taipei, Taiwan. Main Outcome Measure: The QOLIBRI. Results: Of the 6 subscales of the QOLIBRI, 4 (cognition, self, daily life and autonomy, and social relationships) were unidimensional, valid, and reliable, whereas the remaining 2 (emotions and physical problems) exhibited poor unidimensionality, item and person reliability, and person-item targeting. Five items (energy, concentrating, getting out and about, sex life, and achievements) showed considerable differential item functioning among age groups, disability levels, and time since traumatic brain injury. Conclusion: According to item response theory, we identified psychometric issues in the emotions and physical problems subscales of the QOLIBRI as well as several differential item functioning items. Future research is required to determine whether similar results are observed in other language versions of the QOLIBRI or in other countries.