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(1) Background: This study aims to analyze the bioelectrical activity of the masticatory and cervical muscles in a subject with anisometropia. (2) Methods: A female patient aged 23 years with a best-corrected visual acuity of 1.0 in the right eye and 0.1 in the left eye, a refractive error of −2.25 Dsph in the right eye and +4.25 Dsph in the left eye, and astigmatism of −1.75 Dcyl axis 24° was examined. A comprehensive ophthalmological examination and the study of the bioelectrical activity of the muscles were carried out. During the ophthalmological examination, best-corrected visual acuity was determined, refractive error (spherical equivalent) was assessed, and additionally, retinal thickness, choroidal thickness, axial length, and intraocular pressure were measured. (3) Results: It was demonstrated that higher tension in the resting mandibular position and pain-free maximum unassisted opening were observed on the right side (myopia). Conversely, higher tension during maximum voluntary clenching in the intercuspal position and maximum voluntary clenching on dental cotton rolls in the intercuspal position was observed on the left side (hyperopia and astigmatism). (4) Conclusions: In the case study, muscle asymmetry was demonstrated, which is likely associated with anisometropia. This phenomenon requires further investigation. [ABSTRACT FROM AUTHOR]

The aim of this study was to pharmacologically induce accommodative paralysis and evaluate its effects on the bioelectrical activity of the muscular system. The study included two participant groups: those with myopia and those with normal vision (emmetropes). Electromyographic assessments were performed using the Noraxon Ultium DTS 8-K MR 3 myo Muscle Master Edition system. The muscles analyzed in this study were the temporalis, masseter, sternocleidomastoid, trapezius, abdominal muscles, biceps brachii, and the external oblique muscles of the abdomen. It is important to acknowledge that, based on the current findings, it cannot be definitively stated that the observed effects have clinical significance, and additional studies are encouraged. [ABSTRACT FROM AUTHOR]

The presented narrative review aims to present the impact of therapeutic methods on the masticatory muscle activity measured using surface electromyography (sEMG) in patients with temporomandibular disorders (TMDs). Original interventional studies with baseline data for diagnosed TMD groups with full-text articles in English published in scientific journals in the last ten years were included in the evaluation process. The following narrative review considered only clinical, controlled, and randomized studies. Articles that included the following parameters were qualified for this review: adult participants, diagnosis of temporomandibular disorder, the presence of a musculoskeletal dysfunction, no other severe comorbidities, use of therapeutic interventions, and sEMG measurement before and after the intervention. Ten papers were accepted and analyzed for the final evaluation in the presented review. Several studies using surface electromyographic examination prove the effectiveness of various therapies to normalize the bioelectrical activity of the masticatory muscles, either reduction during rest or increase during a functional task in patients diagnosed with temporomandibular disorders. This narrative review shows the influence of manual and physical treatments on electromyographic masticatory muscle activity, including soft tissue mobilization, transcutaneous electrical nerve stimulation, low-level laser therapy, and moist heat therapy. Changes in masticatory muscle activity coincided with changes in TMD-associated pain and range of mandibular mobility. [ABSTRACT FROM AUTHOR]

This study aims to examine the correlations between masticatory and neck muscle thickness and activity versus eyeball length, retinal thickness, choroidal thickness, and intraocular pressure in healthy women versus women with myopia. The study group consisted of 21 women aged 24 years and a control group of 19 women (mean age 23 years). For bioelectrical activity analysis within the temporalis anterior, the superficial part of the masseter muscle, the middle part of the sternocleidomastoid muscle, and the anterior belly of the digastric muscle, an eight-channel BioEMG III electromyograph were used. An M-Turbo ultrasound machine was used to analyze masticatory and neck muscle thickness. The eyeball length was examined by IOL Master 500; choroidal and retinal thickness by Optovue Angiovue; and intraocular pressure by Tono-Pen XL. Refractive errors are related to differences in muscle thickness and electromyographic activity. Bioelectrical activity within the temporalis anterior seems to be associated with ocular length, retinal thickness, and choroidal thickness in women with myopia. [ABSTRACT FROM AUTHOR]

Purpose: Temporomandibular disorders affect from 5 to 12 percent of the population, occurring almost twice as often in women than in men. The painful form of temporomandibular disorders is one of the most common musculoskeletal disorders causing pain. The chronic form is associated with changes in activity of the masticatory muscles and can lead to sleep problems, reduction of emotional state and worsening of quality of life. Methods: 66 women were included in the study group. The study was composed of a clinical evaluation of temporomandibular disorders and assessment of the masticatory muscle activities using surface electromyography. The anterior part of the temporalis muscle and the superficial part of the masseter muscle were evaluated during teeth clenching on cotton rolls. The symmetric activity index was calculated from the results of electromyographic activity. Based on the activity and symmetric activity index values, subjects were qualified to the risk group of temporomandibular disorders. Results: Twenty people (30.3 percent) qualified for the temporomandibular disorders risk group. In the temporomandibular disorders risk group, the mean symmetric activity index value of the anterior part of the temporal muscle was 72.6 percent and the mean electromyographic activity was 143.94 microvolts. In the masseter muscle, the mean symmetric activity index value was 67.7 percent and the mean electromyographic activity was 155.33 microvolts. Conclusions: Temporomandibular disorders may develop in 30.3 percent of examined women. The research should be continued to determine the temporomandibular disorders risk group, which may enable for the appropriate prevention of the development of dysfunctions in the stomatognathic system. [ABSTRACT FROM AUTHOR]

Introduction. Muscle fatigue has been studied for a long time with the use of a wide variety of exercise models, protocols and assessment methods, among which surface electromyography (sEMG) is most commonly used. The main sEMG parameters (amplitude and frequency) are prevalently used to evaluate the level of muscle fatigue in static and dynamic contractions. Objective. The purpose of this study is to determine and compare 2 separate indices: IF1 basis of the sEMG signal amplitude analysis and IF2 basis of the sEMG median frequency analysis, related to muscles fatigue during an isometric contraction. Materials and method. The study was performed on 60 professional runners divided into 2 equal groups. The first group comprised sprinters, competing in short distance track and field events (100 and 200 meters). The second group consisted of middle-distance runners, competing in middle-distance track and field events (800 and 1,500 meters). The electrical activity of the VMO muscles of the right and left lower limbs was recorded simultaneously during isometric activity in a squatting position. The sEMG data was used to determine and compare IF1 and IF2 indices. Results. During isometric measurement, sprinters presented a much more significant increase in the mean amplitude of sEMG signal in comparison to middle-distance runners (mean IF1 difference: 0.228; p=0.007). Analysis of the median frequency did not show significant differences between the 2 groups (mean IF2 difference: 0.037; p=0.12). Conclusions. Change in sEMG amplitude during isometric exercise may be related to muscles fatigue. The use of fatigue indices, based on sEMG amplitude, as an objective indicator of the efficacy of an endurance training programme for sportsmen requires further research. [ABSTRACT FROM AUTHOR]

Introduction. Pathological muscle tone can cause changes in the facial skeleton, including tension headaches, tinnitus, temporomandibular joint dysfunctions. The complexity of pathologies and their spectrum may also indicate changes beyond the facial skeleton. The aim of the study was to determine the possible correlation between the pressure pain threshold of the trapezius muscle and the bioelectrical tension on the masticatory muscles. Aim. The aim of the study was to determine the possible correlation between the pressure pain threshold of the trapezius muscle and the bioelectric tension on the masticatory muscles. Material and methods. The number of 36 women applied for the study. They were all examined using an algometer within a trapezius muscle to determine the pressure pain threshold. The electromyographic study was carried out in accordance with the SENIAM guidelines. The resting activity of selected masticatory muscles (temporal and masseter) was recorded for 10 sec. The study involved an 8-channel BioEMG IIITM surface electromyography apparatus with BioPak Measurement System (BioResearch Associates, Inc. Milwaukee, WI, USA). Statistical analysis was carried out using the r-Pearson test. The level of significance was set at 5%. Results. After comparing the bioelectric tension of the masticatory muscles and the pressure pain threshold, left-sided correlation was observed (p<0.05). Both in the right-hand and general comparison, the results did not reach the required level of statistical significance (p>0.05). Conclusions. The pressure pain threshold seems to be linked to the bioelectrical muscle tone of the masticatory muscles. To confirm this observation, further research into a larger and more diverse group of participants is recommended. [ABSTRACT FROM AUTHOR]