October 2017

Between-days intra-rater reliability with a hand held myotonometer to quantify muscle tone in the acute stroke population

Authors: Wai Leung Ambrose Lo, Jiang Li Zhao, Ling Chen, Di Lei, Dong Feng Huang & Kin Fai Tong

Affiliations: Department of Rehabilitation Medicine, Guangdong Engineering and Technology Research Center for Rehabilitation Medicine and Translation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China

Journal: Nature - Scientific Reports - October 2017, Volume 7, Article no. 14173 (DOI: 10.1038/s41598-017-14107-3)

A myotonometer can objectively quantify changes in muscle tone. The between-days intra-rater reliability in a ward setting for the acute stroke population remains unknown. This study aimed to investigate the device’s between-days intra-rater reliability when used in a ward setting for acute stroke participants. Muscle tone of biceps brachii, brachioradialis, rectus femoris, and tibialis anterior was recorded in the ward at bedside by one physiotherapist on two consecutive days. This study included participants who were within 1 month of their first stroke occurrence. Participants who were medically unstable or who suffered from brain stem injury were excluded. Reliability was assessed by the intraclass correlation coefficient (ICC), standard error of measurement (SEM), smallest real difference (SRD), and the Bland-Altman limits of agreement. The results indicated excellent between-days intra-rater reliability (ICC > 0.75). SEM and SRD show small differences between measurements. The Bland-Altman analysis indicated a tendency of overestimation of the rectus femoris.

This present study demonstrates that MyotonPRO has acceptable between-days intra-rater reliability in measuring muscle tone in a ward setting. Agreement between measurements is acceptable, while measurement error is comparable with the existing literature. One must be cautious when interpreting the results due to the limitations of the study.