Cross-cultural adaptation and psychometric properties of the Turkish version of the Dresden Fall Questionnaire (DREFAQ-Tr) in Parkinson’s disease

Abstract Background Falls are a major complication of Parkinson’s disease and require reliable patient-reported assessment. The Dresden Fall Questionnaire (DREFAQ) is a brief tool assessing falls and related fear. This study aimed to translate and cross-culturally adapt the DREFAQ into Turkish (DREFAQ-Tr) and evaluate its psychometric properties in people with Parkinson’s disease. Methods The study had two phases: DREFAQ was translated and cross-culturally adapted into Turkish, then its psychometric properties were evaluated in people with Parkinson’s disease, with test–retest reliability assessed after 2 weeks. The adaptation followed international translation and cultural adaptation guidelines. Content validity was addressed qualitatively through expert committee review, which evaluated item relevance, clarity, and cultural appropriateness during the adaptation process. Sixty-four individuals with Parkinson’s disease completed the DREFAQ-Tr and comparator scales, including the Modified Falls Efficacy Scale (MFES) and the Parkinson’s Disease Questionnaire-8 (PDQ-8). Internal consistency, test–retest reliability, construct and convergent validity (correlations with MFES and PDQ-8), and measurement precision (SEM, MDC95) were examined. Exploratory factor analysis was conducted to evaluate construct validity. Results The DREFAQ-Tr demonstrated adequate internal consistency (Cronbach’s alpha = 0.731; CR = 0.92). Item–total correlations ranged from 0.433 to 0.585. Test–retest reliability was excellent, with ICC values of 0.962 (Near Falls with Fear of Falling), 0.958 (Severe Falls with Injuries), and 0.954 (total score). Bland–Altman analysis revealed a mean difference of 0.28 with 95% limits of agreement (–1.48 to + 2.04), indicating strong agreement. Factor analysis supported a two-factor structure explaining 86.25% of the variance, with clean loadings and no cross-loadings. Convergent validity was confirmed by a strong negative correlation with MFES and a strong positive correlation with PDQ-8. Measurement error analysis yielded SEM = 0.60 and MDC95 = 2.35. No significant floor or ceiling effects were detected. Conclusion The DREFAQ-Tr is a reliable and valid instrument for assessing fall-related events in Turkish individuals with Parkinson’s disease. Its strong psychometric performance supports its use in both clinical practice and research. Future studies with longitudinal designs are warranted to evaluate responsiveness and minimal important change (MIC) using anchor-based approaches, beyond the MDC95 estimated in the present study.