Myotonometric comparison of sternocleidomastoideus and masseter muscles in multiple sclerosis patients with swallowing problem and healthy individuals

Background: Dysphagia occurring in the oral and pharyngeal phases of swallowing in MS patients may be caused by changes in muscles' viscoelasticity. The aim of this study was to compare the muscles' (sternocloideomastoideus and masseter) viscoelasticity properties by myotonometer between MS patients and healthy individuals.Methods: This study design was a cross-sectional, non-interventional study. Ten healthy individuals were allocated to the control group, eleven MS patients without swallowing problems were allocated to the without swallowing group, ten MS patients with swallowing problems were allocated to the swallowing group. Disability was evaluated using the Expanded Disability Status Scale (EDSS), swallowing problem was assessed with Dysphagia in Multiple Sclerosis (DYMUS) scale, and to measure the viscoelastic parameters (tone, stiffness, elasticity) of sternocloideomastoideus (SCM) and masseter muscles bilaterally, MyotonPro (R) was used. The comparison between the groups was performed using the Kruskal-Wallis H test.Results: It was observed that there was no difference in terms of viscoelastic properties of the masseter muscle in groups (p > 0.05). There was no difference between the groups in terms of the elasticity of the SCM muscle (p > 0.05). However, the tonus and stiffness of the SCM on the left side of the MS patients were higher than in other groups (p = 0.050, p = 0.005).Conclusion: The increment level of tone and stiffness of SCM muscle is related to swallowing problems in patients with MS. Due to swallowing problems in MS, the orofacial and neck region's muscles' viscoelastic properties may change in time and may be affected by phases of swallowing problems.

Automated summary

This study compared the viscoelastic properties of the sternocloideomastoideus and masseter muscles between MS patients and healthy individuals. The results showed that the tonus and stiffness of the SCM muscle on the left side were higher in MS patients, which is related to swallowing problems.