October 2017

Relative and Absolute Interrater Reliabilities of a Hand-Held Myotonometer to Quantify Mechanical Muscle Properties in Patients with Acute Stroke in an Inpatient Ward

Authors: Wai Leung Ambrose Lo 1, 2, Jiang Li Zhao 1, Le Li 1, Yu Rong Mao 1, and Dong Feng Huang 1


  1. Department of Rehabilitation Medicine, Guangdong Engineering and Technology Research Center for Rehabilitation Medicine and Translation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
  2. Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK

Journal: BioMed Research International - Volume 2017, Article ID 4294028, 12 pages (DOI: 10.1155/2017/4294028)

Introduction: The reliability of using MyotonPRO to quantify muscles mechanical properties in a ward setting for the acute stroke population remains unknown.

Objective: To investigate the within-session relative and absolute interrater reliability of MyotonPRO.

Methods: Mechanical properties of biceps brachii, brachioradialis, rectus femoris, and tibialis anterior were recorded at bedside. Participants were within 1 month of the first occurrence of stroke. Relative reliability was assessed by intraclass correlation coefficient (ICC). Absolute reliability was assessed by standard error of measurement (SEM), SEM%, smallest real difference (SRD), SRD%, and the Bland-Altman 95% limits of agreement.

Results: ICCs of all studied muscles ranged between 0.63 and 0.97. The SEM of all muscles ranged within 0.30–0.88 Hz for tone, 0.07–0.19 for decrement, 6.42–20.20 N/m for stiffness, and 0.04–0.07 for creep. The SRD of all muscles ranged within 0.70–2.05 Hz for tone, 0.16–0.45 for decrement, 14.98–47.15 N/m for stiffness, and 0.09–0.17 for creep.

Conclusions: MyotonPRO demonstrated acceptable relative and absolute reliability in a ward setting for patients with acute stroke. However, results must be interpreted with caution, due to the varying level of consistency between different muscles, as well as between different parameters within a muscle.

The study has demonstrated that the MyotonPRO has acceptable relative and absolute interrater reliabilities when measuring mechanical muscle properties in a ward setting. Agreement between raters measurement was high with low measurement errors. Although the MyotonPRO is a more useful instrument for objectively quantifying muscle properties than subjective scales, one must be cautious when interpreting the results since reliability of the device does not appear to be consistent throughout all muscle groups and within all the parameters it measures. Further research to understand the validity of myotonometric measures in a ward setting is recommended.