The Turkish version of the PDQ-Exercise demonstrated acceptable psychometric properties including good structural validity after model modifications, moderate construct validity, acceptable internal consistency, and excellent test-retest reliability, but exhibited a significant floor effect in a sample predominantly consisting of individuals with early-stage PD.
Key Findings
Results
The initial confirmatory factor analysis model of the Turkish PDQ-Exercise showed poor fit, but following theoretically and statistically justified modifications, the final model demonstrated good fit indices.
Modifications included the addition of correlated residuals between selected items
Final model fit indices: CFI = 0.991, TLI = 0.981, SRMR = 0.051
RMSEA = 0.051 with 90% CI: 0.00–0.145, indicating some uncertainty
Study involved 70 people with Parkinson's disease (pwPD)
Structural validity was examined using confirmatory factor analysis (CFA)
Results
Construct validity of the Turkish PDQ-Exercise was supported by moderate correlations with clinical, participation, and quality of life measures.
Correlation with Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS): ρ = 0.545
Correlation with Oxford Participation and Activities Questionnaire: ρ = 0.514
Correlation with Parkinson's Disease Questionnaire-8 (PDQ-8): ρ = 0.494
All correlations were described as moderate
Construct validity was assessed through predefined hypotheses regarding expected relationships with related measures
Results
The Turkish PDQ-Exercise demonstrated acceptable internal consistency as measured by Cronbach's alpha and McDonald's omega.
Cronbach's alpha = 0.783
McDonald's omega = 0.788
Both values fall within the range described as 'acceptable internal consistency'
Sample size was 70 pwPD
Results
The Turkish PDQ-Exercise demonstrated excellent test-retest reliability with low measurement error.
Intraclass Correlation Coefficient (ICC) = 0.985
Standard Error of Measurement (SEM) = 2.6
Minimal Detectable Difference (MDD) = 7.2
Reliability was also assessed using Bland-Altman analysis
Results
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
The floor effect was noted as a limitation in the context of the sample characteristics
The sample predominantly consisted of individuals with early-stage Parkinson's disease
Floor effects indicate the scale may have limited sensitivity for detecting differences among lower-severity patients
Background
The PDQ-Exercise is described as the first patient-reported outcome measure specifically designed to assess exercise-related challenges in people with Parkinson's disease.
The tool captures exercise-specific barriers and challenges rather than general quality of life or motor symptoms
The study involved cross-cultural adaptation including translation into Turkish
70 pwPD were recruited for psychometric validation
Psychometric properties evaluated included structural validity, construct validity, internal consistency, test-retest reliability, measurement error, and floor/ceiling effects
What This Means
This research suggests that a Turkish translation of a questionnaire called the PDQ-Exercise, which measures how difficult it is for people with Parkinson's disease to exercise, can be used reliably in Turkish-speaking patients. The study recruited 70 people with Parkinson's disease in Turkey and put the translated questionnaire through a series of tests to check whether it accurately measures what it is supposed to measure and whether it gives consistent results over time. The questionnaire showed strong reliability — meaning patients gave very similar answers when they completed it on two separate occasions — and it correlated reasonably well with other established measures of Parkinson's disease severity, daily participation, and quality of life.
However, the study found that the questionnaire's internal structure needed some adjustments to fit well with the Turkish sample, and the researchers made theoretically justified modifications to the statistical model to achieve an acceptable fit. One notable limitation was a significant 'floor effect': about 29% of participants scored the lowest possible score (zero), suggesting the questionnaire may not be sensitive enough to detect differences among people with mild or early-stage Parkinson's disease, which was the predominant group in this study.
This research matters because exercise is an important part of managing Parkinson's disease, and having a validated tool to identify exercise-specific barriers in Turkish-speaking patients could help clinicians tailor exercise programs more effectively. The findings suggest the Turkish PDQ-Exercise is a useful and reliable instrument, though clinicians should be cautious when using it with patients who have early-stage disease, as it may not capture subtle differences in exercise challenges within that group.
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Yalçın M, Kahraman T, Dönmez Çolakoğlu B, Genç A. (2026). Cross-Cultural Adaptation and Psychometric Evaluation of the Turkish Version of the Exercise-Specific Parkinson's Disease Questionnaire.. Brain and behavior. https://doi.org/10.1002/brb3.71447