Abstract / Summary
Myotonometry provides a non-invasive assessment of resting muscle mechanical properties, but its reliability and functional relevance in Parkinson’s disease (PD) remain insufficiently established. This study examined the within-session intra-rater reliability of MyotonPRO measurements and explored their associations with clinical motor severity, gait, functional mobility, and manual dexterity in 24 people with PD assessed in the ON-medication state. Frequency, stiffness, logarithmic decrement, relaxation time, and creep were measured bilaterally in the biceps brachii, triceps brachii, tibialis anterior, and medial gastrocnemius. Reliability between two sets of five impulses was assessed using ICC(3,2), and associations were examined using Spearman correlations with Benjamini–Hochberg false discovery rate correction. Under the standardized same-session, same-rater protocol, all parameters showed good-to-excellent reliability point estimates (ICC = 0.823–0.988), although the precision of some estimates was limited by relatively wide confidence intervals. No significant associations were found with MDS-UPDRS III scores, Hoehn and Yahr stage, or Timed Up and Go performance. Several moderate nominal correlations were observed between lower-limb myotonometric parameters and preferred gait performance, and between triceps brachii parameters and Grooved Pegboard completion time (|rs| = 0.410–0.488); however, none remained significant after false discovery rate correction. Thus, the reliability findings apply to the present standardized protocol, whereas the associations with motor performance remain exploratory and hypothesis-generating.