Reliability and variability of self-reported physical activity and exercise self-efficacy measures among people with Parkinson disease

Purpose: To explore reliability and inherent variability of physical activity (PA) and exercise self-efficacy (ESE) questionnaires and association of PA with ESE in people with Parkinson disease (PwP). Material and methods: International Physical Activity Questionnaire (IPAQ), Brunel Lifestyle Physical Activity Questionnaire (BLPAQ), and ESE data were collected from 30 PwP (NCT049222190). Intraclass correlation coefficients (ICC) and Minimal Detectable Change (MDC₉₀) were calculated to determine test-retest reliability and inherent variability. Pearson correlation analyzed relationship of ESE with PA measures. Results: Test-retest reliability was moderate for IPAQ, good for BLPAQ Planned, moderate for BLPAQ Unplanned, and moderate for ESE. Test-retest reliability was good for IPAQ ≤ 2000 MET-minutes/week and poor for IPAQ ≥ 2000 MET-minutes/week as per subgroup analysis. MDC₉₀ was 2132 MET-minutes/week for IPAQ, 0.97 for BLPAQ Planned, 0.87 for BLPAQ Unplanned, and 21.06 for ESE. ESE showed strong positive association with IPAQ, poor positive association with BLPAQ Planned, and moderately positive association with BLPAQ Unplanned. Conclusion: IPAQ, BLPAQ, and ESE exhibit consistency across sessions and can be used to record PA and ESE among PwP. However, there are limitations, particularly for higher PA levels. MDC₉₀ scores of PA and ESE measures can help determine effectiveness of PA interventions in PwP.