Factorial validity and comparability of the six translations of the Rivermead Post-Concussion Symptoms Questionnaire translations: results from the CENTER-TBI study
Authors: Zeldovich Marina , Bockhop Fabian , Covic Amra , Mueller Isabelle , Polinder Suzanne , Mikolic Ana , van der Vlegel Marjolein , von Steinbuechel Nicole ,   CENTER-TBI participants and investigators, Åkerlund Cecilia , Amrein Krisztina , Andelic Nada , Andreassen Lasse , Anke Audny , Antoni Anna , Audibert Gérard , Azouvi Philippe , Azzolini Maria Luisa , Bartels Ronald , Barzó Pál , Beauvais Romuald , Beer Ronny , Bellander Bo-Michael , Belli Antonio , Benali Habib , Berardino Maurizio , Beretta Luigi , Blaabjerg Morten , Bragge Peter , Brazinova Alexandra , Brinck Vibeke , Brooker Joanne , Brorsson Camilla , Buki Andras , Bullinger Monika , Cabeleira Manuel , Caccioppola Alessio , Calappi Emiliana , Calvi Maria Rosa , Cameron Peter , Carbayo Lozano Guillermo , Carbonara Marco , Cavallo Simona , Chevallard Giorgio , Chieregato Arturo , Citerio Giuseppe , Clusmann Hans , Coburn Mark , Coles Jonathan , Cooper Jamie D. , Correia Marta , Čović Amra , Curry Nicola , Czeiter Endre , Czosnyka Marek , Dahyot-Fizelier Claire , Dark Paul , Dawes Helen , De Keyser Véronique , Degos Vincent , Della Corte Francesco , Boogert Hugo den , Depreitere Bart , Đilvesi Đula , Dixit Abhishek , Donoghue Emma , Dreier Jens , Dulière Guy-Loup , Ercole Ari , Esser Patrick , Ezer Erzsébet , Fabricius Martin , Feigin Valery L. , Foks Kelly , Frisvold Shirin , Furmanov Alex , Gagliardo Pablo , Galanaud Damien , Gantner Dashiell , Gao Guoyi , George Pradeep , Ghuysen Alexandre , Giga Lelde , Glocker Ben , Golubovic Jagoš , Gomez Pedro A. , Gratz Johannes , Gravesteijn Benjamin , Grossi Francesca , Gruen Russell L. , Gupta Deepak , Haagsma Juanita A. , Haitsma Iain , Helbok Raimund , Helseth Eirik , Horton Lindsay , Huijben Jilske , Hutchinson Peter J. , Jacobs Bram , Jankowski Stefan , Jarrett Mike , Jiang Ji-yao , Johnson Faye , Jones Kelly , Karan Mladen , Kolias Angelos G. , Kompanje Erwin , Kondziella Daniel , Kornaropoulos Evgenios , Koskinen Lars-Owe , Kovács Noémi , Kowark Ana , Lagares Alfonso , Lanyon Linda , Laureys Steven , Lecky Fiona , Ledoux Didier , Lefering Rolf , Legrand Valerie , Lejeune Aurelie , Levi Leon , Lightfoot Roger , Lingsma Hester , Maas Andrew I. R. , Castaño-León Ana M. , Maegele Marc , Majdan Marek , Manara Alex , Manley Geoffrey , Martino Costanza , Maréchal Hugues , Mattern Julia , McMahon Catherine , Melegh Béla , Menon David , Menovsky Tomas , Mikolic Ana , Misset Benoit , Muraleedharan Visakh , Murray Lynnette , Negru Ancuta , Nelson David , Newcombe Virginia , Nieboer Daan , Nyirádi József , Olubukola Otesile , Oresic Matej , Ortolano Fabrizio , Palotie Aarno , Parizel Paul M. , Payen Jean-François , Perera Natascha , Perlbarg Vincent , Persona Paolo , Peul Wilco , Piippo-Karjalainen Anna , Pirinen Matti , Pisica Dana , Ples Horia , Polinder Suzanne , Pomposo Inigo , Posti Jussi P. , Puybasset Louis , Radoi Andreea , Ragauskas Arminas , Raj Rahul , Rambadagalla Malinka , Retel Helmrich Isabel , Rhodes Jonathan , Richardson Sylvia , Richter Sophie , Ripatti Samuli , Rocka Saulius , Roe Cecilie , Roise Olav , Rosand Jonathan , Rosenfeld Jeffrey V. , Rosenlund Christina , Rosenthal Guy , Rossaint Rolf , Rossi Sandra , Rueckert Daniel , Rusnák Martin , Sahuquillo Juan , Sakowitz Oliver , Sanchez-Porras Renan , Sandor Janos , Schäfer Nadine , Schmidt Silke , Schoechl Herbert , Schoonman Guus , Schou Rico Frederik , Schwendenwein Elisabeth , Sewalt Charlie , Singh Ranjit D. , Skandsen Toril , Smielewski Peter , Sorinola Abayomi , Stamatakis Emmanuel , Stanworth Simon , Stevens Robert , Stewart William , Steyerberg Ewout W. , Stocchetti Nino , Sundström Nina , Takala Riikka , Tamás Viktória , Tamosuitis Tomas , Taylor Mark Steven , Te Ao Braden , Tenovuo Olli , Theadom Alice , Thomas Matt , Tibboel Dick , Timmers Marjolein , Tolias Christos , Trapani Tony , Tudora Cristina Maria , Unterberg Andreas , Vajkoczy Peter , Vallance Shirley , Valeinis Egils , Vámos Zoltán , van der Jagt Mathieu , Van der Steen Gregory , van der Naalt Joukje , van Dijck Jeroen T. J. M. , van Erp Inge A. M. , van Essen Thomas A. , Van Hecke Wim , van Heugten Caroline , Van Praag Dominique , van Veen Ernest , Vande Vyvere Thijs , van Wijk Roel P. J. , Vargiolu Alessia , Vega Emmanuel , Velt Kimberley , Verheyden Jan , Vespa Paul M. , Vik Anne , Vilcinis Rimantas , Volovici Victor , von Steinbüchel Nicole , Voormolen Daphne , Vulekovic Petar , Wang Kevin K. W. , Whitehouse Daniel , Wiegers Eveline , Williams Guy , Wilson Lindsay , Winzeck Stefan , Wolf Stefan , Yang Zhihui , Ylén Peter , Younsi Alexander , Zeiler Frederick A. , Zelinkova Veronika , Ziverte Agate , Zoerle Tommaso 
Published: September 2023

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 factorial validity and 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 estimated using 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 a confirmatory factor analysis framework.

Results
The results did not indicate a violation of the MI assumption. The six RPQ translations were largely comparable 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 indices for the total sample: χ2 (101) = 647.04, $${\chi }^{2}/df$$

χ

2

/
d
f

= 6.41, p < 0.001, CFI = 0.995, TLI = 0.994, RMSEA = 0.055, CI90%[0.051, 0.059], SRMR = 0.051.

Conclusion
The RPQ can be used in international research and clinical settings, allowing direct comparisons of scores across languages analyzed within the full spectrum of TBI severity. To strengthen the aggregated applicability across languages, further analyses of the utility of the response scale and comparisons between different translations of the RPQ at the item level are recommended.