Reliability and validity of the adapted Finnish version of the early onset scoliosis questionnaire (EOSQ-24)

Background: EOSQ-24 is a disease specific patient-reported outcome score used to assess the quality of life in patients with early-onset scoliosis. The aim of this study was to translate and cross-culturally adapt the English version of the EOSQ-24 to Finnish language and to assess the reliability and validity of the translation. Methods: Cross-cultural adaptation and cross-cultural validation were performed to the Finnish translation of the EOSQ-24. Patients and/or their caretakers were then recruited to assess the psychometric properties of the translation. We assessed the internal consistency, test–retest reliability, floor and ceiling effects, and discriminative abilities. One-hundred-and-three patients filled the questionnaire. Results: EOSQ-24 was successfully translated into Finnish. The translation showed excellent internal consistency (Cronbach alpha 0.94), satisfactory item-total correlations ranging from 0.6 to 0.9, and moderate to strong inter item correlations. Test–retest reliability ranged from 0.7 to 0.96 indicating good to excellent agreement. Patients with neuromuscular and syndromic scoliosis reported lower EOSQ-24 scores when compared to patients’ idiopathic and congenital scoliosis. There was a significant negative correlation between major curve and EOSQ-24 scores in patients with idiopathic early onset scoliosis. Conclusion: The internal consistency and test–retest reliability of the measure were found to be satisfactory. A marked ceiling effect was observed, indicating a potential source of error.