Electromyographic Patterns of Masticatory Muscles in Relation to Active Myofascial Trigger Points of the Upper Trapezius and Temporomandibular Disorders.

Grzegorz Zieliński,Jacek Szkutnik,Michał Ginszt,Piotr Majcher,Aleksandra Byś

doi:10.3390/diagnostics11040580

Grzegorz Zieliński, Jacek Szkutnik + Show 3 more

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https://doi.org/10.3390/diagnostics11040580

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Journal: Diagnostics (Basel, Switzerland)	Publication Date: Mar 24, 2021
Citations: 14	License type: CC BY 4.0

Affiliation: Medical University of Lublin

Abstract

The presented study aimed to analyze and compare the electromyographic patterns of masticatory muscles in subjects with active myofascial trigger points (MTrPs) within upper trapezius, patients with temporomandibular disorders (TMDs) and healthy adults. Based on the diagnostic criteria of MTrPs according to Travell & Simons and the Research Diagnostic Criteria for Temporomandibular Disorders, 167 people were qualified for the study. Subjects were divided into 3 groups: with active MTrPs in the upper trapezius, with diagnosed temporomandibular disorders (TMDs) and healthy adults. Measurements of the bioelectric activity of the temporalis anterior (TA) and masseter muscle (MM) were carried out using the BioEMG III ™. Based on statistical analysis, significantly lower values of TA resting activity were observed among controls in comparison to MTrPs (1.49 μV vs. 2.81 μV, p = 0.00) and TMDs (1.49 μV vs. 2.97 μV, p = 0.01). The POC index values at rest differed significantly between MTrPs and TMDs (86.61% vs. 105%, p = 0.04). Controls presented different electromyographic patterns within AcI in comparison to both MTrPs (4.90 vs. −15.51, p = 0.00) and TMDs (4.90 vs. −16.49, p = 0.00). During clenching, the difference between MTrPs and TMDs was observed within MVC TA (91.82% vs. 116.98%, p = 0.02). TMDs showed differences within AcI in comparison to both MTrPs group (−42.52 vs. 20.42, p = 0.01) and controls (−42.52 vs. 3.07, p = 0.00). During maximum mouth opening, differences between MTrPs and TMDs were observed within the bioelectric activity of masseter muscle (16.45 μV vs. 10.73 μV, p = 0.01), AsI MM (0.67 vs. 11.12, p = 0.04) and AcI (13.04 vs. −3.89, p = 0.01). Both the presence of MTrPs in the upper trapezius and TMDs are related to changes in electromyographic patterns of masticatory muscles.

Highlights

Myofascial trigger points (MTrPs) are defined as hyperactive points located in the tense area of the skeletal muscle or its fascia
Both the presence of MTrPs in the upper trapezius and temporomandibular disorders (TMDs) are related to changes in electromyographic patterns of masticatory muscles
The inclusion criteria used in the presented study were: age range 18–35 years, good or very good general health status according to the RDC/TMD questionnaire, the presence of active MTrPs in the upper trapezius and absence of any type of TMDs (MTrPs group), presence of pain-related TMDs based on the Research Diagnostic Criteria for Temporomandibular Disorders RDC/TMD [23] without MTrPs in the upper trapezius (TMDs group)

Summary

Introduction

Myofascial trigger points (MTrPs) are defined as hyperactive points located in the tense area of the skeletal muscle or its fascia. MTrPs are associated with the development of myofascial pain syndrome (MPS), causing local or referred pain [1]. The compression stimulation of MTrPs may induce a local pain sensation or a referred pain response [2]. The development of MTrPs may be caused by the accumulation of microtraumas within the muscle or its direct injury [1,3]. MTrPs can arise as a result of nutrient deficiencies, hormonal disorders or muscle imbalances [4], fatigue and even viral infections [2,5]. It is estimated that the prevalence of MPS in clinical populations varies widely, ranging from 9% to 85% [9]

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