Reference values for the adolescent post version of the Postconcussion Symptom Inventory from the German general population

The present study aims at providing reference values from the general pediatric population for the German version of the 21-item self-report post version of the Postconcussion Symptom Inventory for adolescents aged 13-17 years (PCSI-SR13) following pediatric traumatic brain injury (pTBI). A total of N = 950 adolescents completed an adapted version of the PCSI-SR13. Prior to establishing reference values using percentiles, psychometric properties (i.e., reliability and factorial validity) and regression analyses were examined to identify factors contributing to PCSI-SR13 scores. In addition, construct assessment in the general population sample was compared to that in the pTBI sample (N = 234) using measurement invariance analyses and direct comparisons at the score levels. The results indicate good reliability (Cronbach's α and McDonald's ω of 0.97 each). The four-factor structure covering physical, emotional, cognitive, and fatigue symptom groups could be replicated with χ²(183) = 995.96, p < 0.001, χ²/df = 5.44, CFI = 0.99, TLI = 0.98, RMSEA (90% CI) = 0.068 (0.064, 0.073), SRMR = 0.03. With minor restrictions, the assessment of symptoms was comparable between the general population and the pTBI samples. Participants in the pTBI sample reported a significantly higher symptom burden than those in the general population sample. Reference values were provided using the total sample without further stratification. Conclusion: For the German post version of the PCSI-SR13, reference values are now available for direct score comparisons and for drawing conclusions about the clinical relevance of the reported symptoms, while considering the prevalence in a comparable general population without a history of pTBI.Trial registration: The study is retrospectively registered in the German Clinical Trials Register and in the International Clinical Trials Registry Platform (ID DRKS00032854).