Intrarater and Interrater Reliability of Muscle Tone, Elasticity and Stiffness Characteristics Measurements by Myoton-3 in Healthy Children Aged 5–7 Years

Abstract

Background.  Research  literature  highlights  the  need  to  use  objective  assessment  tools  to  quantify  muscle
tone because all typically used clinical scales of muscle tone have reliability problems. Though hand-held device
Myoton-3 has been used in research with children, its reliability has not been established. The aim of this study was
to investigate intrarater and interrater reliability of muscle tone, elasticity and stiffness measurements by Myoton-3
in healthy children aged 5–7 years.
Methods. A total of 30 healthy children aged between 5 and 7 years participated in the study. Myoton-3 device
was used by two measurers to assess tibialis anterior (TA), rectus femoris (RF), biceps brachii (BB), medial head
of gastrocnemius (GM), biceps femoris (BF), trapezius (TR) and triceps brachii (TB) muscle tone, elasticity and
stiffness values. Measurements were conducted for intrarater reliability on two consecutive days and for interrater
reliability on the same day.
Results.  Intrarater  reliability  expressed  as  intra-class  correlation  of  frequency,  decrement  and  stiffness
characteristics measurements was moderate to high, between 0.60–0.72, while TR muscle ICC was low. Interrater
reliability expressed as intra-class correlation of the frequency, decrement and stiffness characteristics measurements
was high to very high, between 0.72–0.91, while TR muscle ICC was low.
Conclusion. Moderate to high (0.60–0.72) intrarater reliability and high to very high interrater reliability (0.72–
0.91) was established for Myoton-3 measurements in healthy children aged 5–7 years. The Myoton-3 is a reliable
device for measuring skeletal muscle tone, elasticity and stiffness in preschool children.