Applicability and Clinical Utility of the German Rivermead Post-Concussion Symptoms Questionnaire in Proxies of Children after Traumatic Brain Injury: An Instrument Validation Study

Abstract

Abstract Background. The German Rivermead Post-Concussion Symptoms Questionnaire (RPQ) can be used to assess post-concussion symptoms (PCS) after traumatic brain injury (TBI) in adults, adolescents, and children. Methods. In this study, we examined the psychometric properties of the German RPQ proxy version (N = 146) for children (8—12 years) after TBI on the item, total and scale score level. Construct validity was analyzed using rank correlations with the proxy-assessed Post-Concussion Symptoms Inventory (PCSI-P), the Patient Health Questionnaire 9 (PHQ-9), and the Generalized Anxiety Disorder Scale 7 (GAD-7). Furthermore, sensitivity testing concerning subjects’ sociodemographic and injury-related characteristics was performed. Differential item functioning (DIF) was conducted to evaluate the comparability of RPQ proxy ratings in children compared to adolescents. Results. Good internal consistency was shown regarding Cronbach’s α (0.81—0.90) and McDonald’s ω (0.84—0.92). Factorial validity was superior for a three-factor model compared to the original one-factor model. Proxy ratings of the RPQ total and scale scores had strong correlations with the PCSI-P (ϱ = 0.50—0.69), as well as moderate to strong correlations with the PHQ-9 (ϱ = 0.49—0.65) and the GAD-7 (ϱ = 0.44—0.64). DIF analysis revealed no relevant differences between children and adolescent proxy versions. Conclusions: The German RPQ proxy is a psychometrically reliable and valid instrument to assess PCS in children after TBI. Therefore, RPQ self- and proxy-ratings can be used to assess PCS in childhood as well as along the lifespan of an individual after TBI.