November 2018

Reproducibility of the durometer and myoton devices for skin stiffness measurement in healthy subjects

Authors: Laura E. Dellalana, Fuyao Chen, Arved Vain, Jocelyn S. Gandelman, Mihkel Põldemaa, Heidi Chen, Eric R. Tkaczyk

Author information: Vanderbilt University School of Medicine, Nashville, Tennessee, USA

Journal: Skin research & technology - Volume 24, Issue 4 (DOI: 10.1111/srt.12646)


Clinical assessment of skin stiffness is unreliable in many applications. The durometer, an industrial device to measure hardness, has previously been applied in scleroderma. The Myoton is a noninvasive handheld device for assessing soft tissue biomechanical parameters.

Materials and Methods

We evaluated the reproducibility of both devices in six healthy subjects in the volar forearm, dorsal forearm, upper arm, shin, and calf bilaterally. The intraclass correlation coefficient (ICC) was used as a measure of reproducibility among three observers.


The interobserver intraclass correlation coefficient (ICC) of overall stiffness for the Myoton was 0.74 [95% confidence interval (CI) 0.45‐1.00] and 0.71 [0.39‐1.00] for the durometer. Coefficient of variation (CV) for the Myoton was 6.4% [range 1.3‐12.1] and 7.6% [range 4.4‐13.8] for the durometer. Myoton and durometer values had a Pearson correlation of 0.69. The intraobserver Myoton ICC was 0.89 [0.74‐1.00] and CV 3.1% [range 1.6‐5.0]. The 95% confidence minimal detectable change by the Myoton for a single observer is 32.4 N/m, which is 7.6% of the average subject’s overall stiffness.

The Myoton demonstrated high reproducibility, particularly in the overall stiffness parameter, and merits further investigation to assess disease progression and treatment efficacy.