Reliability and convergent validity of the 6-minute pegboard and ring test in people with Parkinson's disease: a cross-sectional study.

BACKGROUND: This study aimed to evaluate the reliability and convergent validity of the 6-Minute Pegboard and Ring Test (6PBRT) in people with Parkinson's disease (PwPD). METHODS: A total of 48 PwPD were included in this cross-sectional study (mean age: 67.0 ± 5.5 years). Upper extremity (UE) function was assessed using the 6PBRT, Nine-Hole Peg Test (9HPT), grip strength, shoulder muscle strength, Quick-DASH, and Fatigue Impact Scale (FIS). Intra-rater and inter-rater reliability were analyzed using the intraclass correlation coefficient (ICC [2,1]), standard error of measurement (SEM), and minimal detectable change (MDC). Agreement was evaluated using Bland-Altman analysis. Convergent validity was assessed using Spearman correlation analysis. RESULTS: The 6PBRT demonstrated excellent intra-rater reliability (ICC = 0.995-0.996) and inter-rater reliability (ICC = 0.995), with low measurement error (SEM = 4.17-4.99 repetitions; MDC = 11.55-13.83 repetitions). Bland-Altman analysis revealed low bias and acceptable limits of agreement, indicating strong absolute reliability. The 6PBRT showed significant moderate-to-strong correlations with the 9HPT (dominant: rho = -0.878; non-dominant: rho = -0.848), shoulder flexor strength (rho = 0.756-0.760), shoulder abductor strength (rho = 0.775-0.787), FIS (rho = -0.657), and Quick-DASH (rho = -0.510) (all p < 0.001). CONCLUSION: The 6PBRT demonstrated high reliability and good convergent validity in PwPD. Its significant correlations with UE motor performance, muscle strength, and fatigue support its potential as a clinically relevant outcome measure in rehabilitation practice and research settings for Parkinson's disease. The results apply to early-to-mid stage Parkinson's disease and should not be extrapolated to more advanced stages.