Cross‐Cultural Adaptation and Psychometric Evaluation of the Turkish Version of the Exercise‐Specific Parkinson's Disease Questionnaire

INTRODUCTION: The Exercise-Specific Parkinson's Disease Questionnaire (PDQ-Exercise) is the first patient-reported outcome measure to assess exercise-related challenges in people with Parkinson's disease (pwPD). The aim was to translate and culturally adapt the PDQ-Exercise into Turkish and to evaluate its psychometric properties in pwPD, including structural and construct validity assessed through predefined hypotheses regarding expected relationships with related measures, internal consistency, test-retest reliability, measurement error, and floor/ceiling effects. METHODS: This cross-cultural adaptation and psychometric validation study involved translating, culturally adapting, and evaluating the psychometric properties of PDQ-Exercise into Turkish. Seventy pwPD were recruited. Structural validity was examined using confirmatory factor analysis (CFA). Construct validity was assessed through correlations with clinical, participation, and quality of life measures. Reliability was assessed through evaluations of internal consistency (Cronbach's alpha and McDonald's omega) and test-retest reliability (ICC) with standard error of measurement (SEM), minimal detectable difference (MDD), and Bland-Altman analysis. RESULTS: The initial CFA model demonstrated poor fit to the data. Following theoretically and statistically justified modifications, including the addition of correlated residuals between selected items, model fit improved substantially. The final model showed good fit indices (CFI = 0.991, TLI = 0.981, SRMR = 0.051), although the RMSEA confidence interval indicated some uncertainty (RMSEA = 0.051, 90% CI: 0.00-0.145). Construct validity was supported by moderate correlations between PDQ-Exercise and Movement Disorder Society Unified Parkinson's Disease Rating Scale (ρ = 0.545), Oxford Participation and Activities Questionnaire (ρ = 0.514), and Parkinson's Disease Questionnaire-8 (ρ = 0.494). PDQ-Exercise demonstrated acceptable internal consistency (Cronbach's alpha = 0.783 and McDonald's omega = 0.788) and excellent test-retest reliability (ICC = 0.985, SEM = 2.6; and MDD = 7.2). The Turkish version of the PDQ-Exercise exhibited a significant floor effect. 28.6% of participants scored the minimum score (0) on the total scale. CONCLUSION: The Turkish version of the PDQ-Exercise demonstrated acceptable psychometric properties in a sample predominantly consisting of individuals with early-stage PD.