Reliability of Selective Neck Muscle Size in Migraine Patients and Healthy Controls Using Ultrasonography

Introduction: In migraine headaches, motor control of muscles is  impaired.  In  this research, thickness measurement of bilateral muscle thickness of upper trapezius (UT) and sternocleidomastoid (SCM) muscles was conducted and intra-rater reliability of the thickness measurement of these muscles was assessed in migraine headache and healthy subjects. 
Materials and Methods: This study was a cross-sectional study to measure bilateral ultrasound images of UT and SCM muscles in 15 patients with migraine headaches and 15 healthy controls. A linear array probe with a 50-mm footprint and frequency range of 7.5 MHz measured the thickness of UT and SCM, parallel to the orientation of the muscle fibers. Intra- class correlation coefficients (ICC) and standard error of measurement (SEM) were used for data analysis. 
Results: The ICC and SEM for thickness measurement of left UT were 0.88 and 0.06 (excellent) and it was 0.87 and 0.07 (excellent) for right UT thickness. The ICC and SEM for left SCM muscle thickness were 0.88 and 0.06 (excellent) and it was 0.85 and 0.08 (excellent) for right SCM thickness. Muscle thickness of the right UT muscle was 13.38±0.92 mm and 11.12±1.00 mm, in migraine and healthy groups, respectively. Also, muscle thickness of the right SCM muscle was 7.24±0.70 mm and 9.16±0.67 mm in migraine and healthy groups, respectively. 
Conclusion: The present study showed that ultrasonography can be a reliable tool to measure cervical muscle thickness in migraine patients. Additionally, the ultrasonography protocol of the current study, the position, and the measurement level can be used with high reliability in future studies.