Comparability of the six Rivermead Post-Concussion Symptoms Questionnaire translations: Results from the CENTER-TBI study

Abstract

Abstract Background Comparison of patient-reported outcomes in multilingual studies requires evidence of the equivalence of translated versions of the questionnaires. The present study examines the comparability of six language versions of the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) administered to individuals following traumatic brain injury (TBI) in the Collaborative European NeuroTrauma Effectiveness Research (CENTER-TBI) study. Methods Six competing RPQ models were fitted to data from Dutch (n = 597), English (n = 223), Finnish (n = 213), Italian (n = 268), Norwegian (n = 263), and Spanish (n = 254) language samples recruited six months after injury. To determine whether the same latent construct was measured by the best-fitting model across languages and TBI severity groups (mild/moderate vs. severe), measurement invariance (MI) was tested using confirmatory factor analysis. Results The results did not indicate a violation of the MI assumption. The six RPQ translations were invariant across languages and were able to capture the same construct across TBI severity groups. The three-factor solution comprising emotional, cognitive, and somatic factors provided the best fit with the following fit indices for the total sample: χ2(101) = 647.04, χ2/df= 6.41, p < 0.001, CFI = 0.995, TLI = 0.994, RMSEA = 0.055, CI90%[0.051, 0.059], SRMR = 0.051. Conclusion The questionnaire can be used in international research, allowing for direct comparisons of scores across languages analyzed within the full spectrum of TBI severity.