Normalization of the electromyographic signals of masticatory muscles during non-habitual chewing activity

There is no consensus on the most appropriate method for normalizing electromyography (EMG) signals from masticatory muscles during isotonic activity. Aim: To analyze the best method for data processing of the EMG signal of the masticatory muscles during isotonic activity (non-habitual chewing), comparing raw data and different types of normalization. Methods: This is a cross-sectional study. Women aged between 18 and 45 years were selected. Anthropometric data were collected (age, height, body mass index ­ BMI, masticatory preference) as well as EMG signal (root mean square ­ RMS) data for the anterior temporal and masseter bilaterally, and for the suprahyoid muscles, during isotonic (non-habitual chewing) and isometric tasks. EMG data were processed offline using Matlab® Software. The normalization of the EMG signal was carried out using the 2nd masticatory cycle, chosen at random, of the 20 cycles collected, the maximum RMS value, and the maximum voluntary contraction (MVC). To analyze the best method of data processing for the isotonic data, the coefficient of variation (CV) was calculated. Descriptive data analysis was adopted, using the mean and standard deviation. ANOVA with repeated measures was used to detect significant differences between the methods of normalization. Statistical significance was set at 5% (α<0.05). Results: The final sample of this research was composed of 86 women. The volunteers presented an average age of 27.83±7.71 years and a mean BMI of 22.85±1.91 Kg/m2. Regarding masticatory preference, 73.25% reported the right side, and 26.75% the left side. Considering the comparison between the methods, the %CV measure of the 2nd cycle showed the lowest variation coefficient during biting for all the muscles from the raw data, RMS Max, and MVC (p=0.001, p=0.003, and p=0.001 respectively). Conclusion: In conclusion, for non-habitual chewing activity, the results of this study recommend data processing using normalization with the second cycle during chewing

Maximum bilateral bite strength and RMS EMG for the diagnosis of myogenic TMD

Aim: The study aimed to evaluate the accuracy of the maximum bilateral molar bite force and the Root Mean Square (RMS) Electromyography (EMG) index of the masticatory muscles in the maximum bilateral molar bite (MMBMax) of women with myogenic Temporomandibular Disorder (TMD) and asymptomatic. Methods: This is a cross-sectional study, composed of 86 women allocated to the TMD Group (n=43) and Control Group (n=43) diagnosis through the Diagnostic Criteria for Temporomandibular Disorders. The maximum bilateral molar bite force was evaluated using a bite dynamometer and the RMS EMG index of the masticatory muscles (anterior temporalis, masseter) during 5 seconds of the MMBMax task. Student t-test was used for data comparison between accuracy of the bite force and RMS EMG of masticatory muscles during the MMBMax. Results: The maximum bilateral molar bite force showed high accuracy (AUC=0.99) for the diagnosis of women with myogenic TMD and asymptomatic women, and the RMS EMG index evaluated during the MMBMax showed a moderate level of accuracy for all masticatory muscles (AUC=0.70 to 0.75). Conclusion: The bilateral bite dynamometer with a surface EMG during bilateral bite can be used to diagnose TMD in young women

Evaluation of integral electromyographic values and median power frequency values in women with myogenous temporomandibular disorder and asymptomatic controls.

BACKGROUND: Surface electromyography (EMG) has been used as a reliable tool for the evaluation of electrical muscle activity. OBJECTIVE: The purpose of this study was to evaluate the EMG indices of the masticatory muscles (masseter, anterior temporalis and suprahyoid) in women with temporomandibular disorder (TMD) and asymptomatic controls in the time domain, by the integrated EMG signal (IEMG) and in the frequency domain, using the median power frequency (MPF). METHODS: An observational, cross-sectional study was conducted involving 30 asymptomatic women as the control (mean age: 25.85 ± 2.57 years) and 74 women with myogenous TMD (mean age: 26.54 ± 2.45 years) diagnosed using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Three EMG readings were taken during maximum voluntary clenching (MVC) of the molars on parafilm for five seconds with a three-minute rest interval between readings. The mixed-model analysis of variance test followed by the Bonferroni correction or the Student-t test was used for the analyses, with the level of significance set to 5% (p < 0.05). RESULTS: IEMG values were significantly higher in the masseter muscles than the anterior temporalis muscles in the control group (p < 0.01). IEMG values were significantly higher in the masseter muscles of the control group than the group with myogenous TMD (p < 0.05). MPF values of the suprahyoid muscles were significantly higher in the myogenous TMD group than the control group. CONCLUSIONS: These significant findings show that women with myogenous TMD have reduction of electrical activity of their masseter muscles and increased firing rate of the motor units of the suprahyoid muscles. These findings may help the treatment of myogenous TMD in women.

Analysis of the accuracy and reliability of the Short-Form Fonseca Anamnestic Index in the diagnosis of myogenous temporomandibular disorder in women.

BACKGROUND: The Fonseca Anamnestic Index is a questionnaire used to classify individuals with temporomandibular disorders. Previous studies have shown that the Fonseca Anamnestic Index provides a multidimensional measurement of the temporomandibular disorders construct and that the main dimension presents a good fit to the model according to the item response theory. OBJECTIVE: To evaluate the between-day reliability, accuracy, and best cut-off score of the Short-Form Fonseca Anamnestic Index for the diagnosis of myogenous temporomandibular disorders. METHODS: The sample consisted of 123 women (57 with myogenous temporomandibular disorders and 66 asymptomatic), evaluated by the Research Diagnostic Criteria for Temporomandibular Disorders. The participants answered the Short-Form Fonseca Anamnestic Index on two occasions with a seven-day interval between tests. For the analysis of between-day reliability, the intraclass correlation coefficient, the standard error of measurement and the minimum detectable change were used. The Receiver Operating Characteristic curve was used to determine the diagnostic accuracy and the best cut-off point. RESULTS: The Short-Form Fonseca Anamnestic Index demonstrated excellent reliability (intraclass correlation coefficient≥0.95) for all items and for the total Short-Form Fonseca Anamnestic Index score (intraclass correlation coefficient=0.98; standard error of measurement=3.28; minimum detectable change=9.09). The level of accuracy of the Short-Form Fonseca Anamnestic Index for the diagnosis of myogenous temporomandibular disorders was high (area under the curve of 0.97), with a better cut-off score of 17.5 points. CONCLUSION: The Fonseca Anamnestic Index should be used in its short form to classify the absence of myogenous temporomandibular disorders (scores between 0 and 15 points) or presence of myogenous temporomandibular disorders (scores between 20 and 50 points) in women.

Efeito da mobilização das raízes nervosas lombares sobre a força e flexibilidade dos músculos do membro inferior / Effect of the mobilization in lumbar nerve roots on muscle strength and flexibility of the lower limb

Introdução: A mobilização neural é bastante aplicada na pratica clínica. Objetivo: Avaliar o efeito da mobilização neural das raízes lombares na força e flexibilidade dos músculos flexores e extensores do joelho. Métodos: Foram selecionados 14 homens (22,4±2,87 anos) saudáveis. A flexibilidade foi avaliada para flexão de joelho (FJD e FJE), extensão de quadril (EQD e EQE) e coluna lombar (FL). A força muscular foi avaliada para flexão e extensão do joelho. As avaliações foram realizadas antes da técnica (PRÉ), imediatamente após (PÓS1) e uma semana após (PÓS2). Resultados: Nas avaliações PÓS1 e PÓS2 foi observado aumento significativo da força muscular na FJE. Para a flexibilidade, na avaliação PÓS1, observou-se aumento significativo na FJE, EQD e EQE. Conclusão: A técnica de mobilização neural promoveu aumento da força dos músculos flexores de joelho esquerdo e da flexibilidade no movimento de flexão de joelho esquerdo, extensão de quadril direito e esquerdo em homens sedentários saudáveis.

Introduction: Neural mobilization is widely applied in clinical practice. Aim: To evaluate the effect of neural mobilization of the lumbar roots on the strength and flexibility of the knee and hip muscles. Methods: We selected 14 men (22.4 ± 2.87 years) healthy. Flexibility was evaluated during knee flexion movements (KFR and KFL), extension of the hip (HER and HEL) and for the lumbar spine (LS). Assessment of muscle strength was performed for the knee movements. The evaluations were performed before the neural mobilization (PRE), immediately after (POST1) and one week after (POST2). Results: In the POST1 and POST2 was a significant increase in muscle strength in KFL. For flexibility, the POST1 evaluation, it was observed significant increase in KFL, HER, and HEL. In the evaluation POST2, a significant increase flexibility in LS and reduction in KFL. Conclusion: The neural mobilization promoted increased strength of the flexor muscles of the left knee, increased flexibility in the KFL, HER, HEL and LS.

Efeitos da manipulação cervical alta sobre a atividade eletromiográfica dos músculos mastigatórios e amplitude de movimento de abertura da boca em mulheres com disfunção temporomandibular: ensaio clínico randomizado e cego / Los efectos de la manipulación cervical en la actividad electromiográfica de los músculos masticatorios y la amplitud del movimiento de apertura de la boca en mujeres con trastorno temporomandibular: un ensayo clínico aleatorizado y ciego / Effects of upper cervical manipulation on the electromyographic activity of the masticatory muscles and the opening range of motion of the mouth in women with temporomandibular disorder: randomized and blind clinical trial

RESUMO Avaliou-se os efeitos da manipulação cervical alta sobre a atividade eletromiográfica de superfície (sEMG) dos músculos mastigatórios e amplitude do movimento de abertura da boca em mulheres com disfunção temporomandibular (DTM). Foram avaliadas 10 mulheres com diagnóstico de DTM miogênica, segundo o Research Diagnostic Criteria for temporomandibular disorders (RDC/TMD), divididas, aleatoriamente, em grupo experimental (GE) n=5, que recebeu manipulação cervical alta e grupo placebo (GP) n=5, que recebeu manobra sem efeito terapêutico. Cinco intervenções foram aplicadas para ambos os grupos uma vez por semana, e avaliações de pré-intervenção, pós-imediato (após a 1ª intervenção) e pós-tardio (48 horas após a 5ª intervenção) foram realizadas. A atividade sEMG foi processada via raiz quadrada da média e normalizada pelo valor de pico (RMS EMGn). Utilizou-se para comparação os testes t de Student e ANOVA two-way (medidas repetidas), adotando-se como significância o valor de 5%, e o Cohen's d para tamanho de efeito de tratamento. Constatou-se a interação significativa grupo × tempo (p<0,05) no RMS EMGn dos músculos temporal direito e esquerdo, na condição de repouso, assim como para todos os músculos mastigatórios durante contração isométrica máxima de elevação e depressão da mandíbula. Os tamanhos de efeito de tratamento moderado a alto foram observados no GE, destacando-se na avaliação pós-tardia. Foi observado também um aumento significativo (p<0,05) e um alto efeito de tratamento na abertura da boca para o GE. A manipulação cervical alta demonstrou equilibrar o RMS EMGn dos músculos mastigatórios e aumentar a amplitude de movimento de abertura da boca em mulheres com DTM miogênica.

RESUMEN En este estudio se evaluaron los efectos de la manipulación cervical alta sobre la actividad electromiográfica de superficie (SEMG) de los músculos masticatorios y de amplitud del movimiento de apertura de la boca en mujeres con trastorno temporomandibular (TTM). Se evaluaron 10 mujeres con diagnóstico de TTM miogénico, con base en el Research Diagnostic Criteria for temporomandibular disorders (RDC/TMD), las que fueron aleatoriamente divididas en grupo experimental (GE) n=5, que recibió manipulación cervical alta, y grupo placebo (GP) n=5, que recibió maniobra sin efecto terapéutico. Se aplicaron cinco intervenciones para ambos grupos una vez por semana, y se realizaron evaluaciones preintervención, posintervención inmediata (después de la 1a. intervención) y posintervención tardía (48 horas después de la 5a. intervención). La actividad SEMG fue calculada mediante raíz cuadrada de la media y normalizada por el valor de pico (RMS EMGn). Se empleó para comparación los test t de Student y ANOVA two-way (medidas repetidas), y el nivel de significancia de 5%, y para el efecto del tratamiento el Cohen's d. Se encontró la interacción significativa grupo × tiempo (p<0,05) en el RMS EMGn de los músculos temporales derecho e izquierdo, en reposo, así como para todos los músculos masticatorios durante la contracción isométrica máxima de elevación y depresión de la mandíbula. Se observaron efectos de tratamiento moderado a alto en el GE, destacando en la etapa posevaluación tardía. También se observó un aumento significativo (p<0,05) y un alto resultado del tratamiento en la apertura de la boca en el GE. La manipulación cervical alta demostró equilibrar el RMS EMGn de los músculos masticatorios y aumentar la amplitud del movimiento de la apertura de la boca en mujeres con TTM miogénica.

ABSTRACT We evaluated the effects of upper cervical manipulation on the surface electromyographic activity (sEMG) of masticatory muscles and range of motion of the opening movement of the mouth in women with temporomandibular disorders (TMD). We evaluated 10 women with myogenic a TMD diagnosis, according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and divided randomly into an experimental group (EG) n=5, which received upper cervical manipulation, and a placebo group (PG) n=5, which received maneuvers without therapeutic effects. Five interventions were performed in both groups, once a week, with performance of pre-intervention assessments, post-immediate assessments (after 1st intervention) and post-delayed assessments (48 hours after the 5th intervention). The sEMG activity was processed using the root mean square and normalized by the peak value (RMS EMGn). We used for comparison the Student's t-test and ANOVA two-way repeated measures, adopting as significance the amount of 5%, and the Cohen d for treatment effect size. We found a significant interaction of group vs time (p<0.05) in the RMS EMGn of the left and right temporal muscles at rest, as well as for all masticatory muscles during maximal isometric contraction during jaw-elevation and jaw-depression. Treatment effect size, high to moderate, was observed in the EG, especially in the post-delayed assessment. We also observed a significant increase (p<0.05) and a high treatment effect during mouth opening in the EG. The upper cervical manipulation demonstrated a balance of the RMS EMGn of the masticatory muscles and increase the opening range of motion of the mouth in women with myogenic TMD.

Immediate and Short-Term Effects of Upper Thoracic Manipulation on Myoelectric Activity of Sternocleidomastoid Muscles in Young Women With Chronic Neck Pain: A Randomized Blind Clinical Trial.

OBJECTIVE: The aim of this study was to assess the immediate and short-term effects of upper thoracic spine manipulation on pain intensity and myoelectric activity of the sternocleidomastoid muscles in young women with chronic neck pain. METHODS: A randomized clinical trial was carried out involving 32 women with chronic neck pain (mean age, 24.8 ± 5.4 years) allocated to an experimental group and a placebo group. Three evaluations were carried out: baseline, immediate postintervention, and short-term postintervention (48-72 hours after intervention). Myoelectric activity of the right and left sternocleidomastoid muscles was assessed at rest and during isometric contractions for cervical flexion and elevation of the shoulder girdle. Neck pain intensity was assessed at rest using a visual analog scale. Comparisons of the data were performed using 2-way repeated-measures analysis of variance with the Bonferroni correction. The level of significance was set at P < .05. RESULTS: A moderate treatment effect on myoelectric activity of the right and left sternocleidomastoid muscles during isometric elevation of the shoulder girdle was found in the experimental group only on the short-term postintervention evaluation (d > 0.40). No statistically significant differences were found for any of the variables analyzed in the intergroup comparisons at the different evaluation times (P > .05). CONCLUSION: No statistically significant differences were found in the intragroup or intergroup analyses of the experimental and placebo groups regarding myoelectric activity of the cervical muscles or the intensity of neck pain at rest in the immediate or short-term postintervention evaluations.

Accuracy of the surface electromyography RMS processing for the diagnosis of myogenous temporomandibular disorder.

Due to the multifactor etiology of temporomandibular disorder (TMD), the precise diagnosis remains a matter of debate and validated diagnostic tools are needed. The aim was to determine the accuracy of surface electromyography (sEMG) activity, assessed in the amplitude domain by the root mean square (RMS), in the diagnosis of TMD. One hundred twenty-three volunteers were evaluated using the Research Diagnostic Criteria for Temporomandibular Disorders and distributed into two groups: women with myogenous TMD (n=80) and women without TMD (n=43). The volunteers were then submitted to sEMG evaluation of the anterior temporalis, masseter and suprahyoid muscles at rest and during maximum voluntary teeth clenching (MVC) on parafilm. The accuracy, sensitivity and specificity of the muscle activity were analyzed. Differences between groups were found in all muscles analyzed at rest as well as in the masseter and suprahyoid muscles during MVC on parafilm. Moderate accuracy (AUC: 0.74-0.84) of the RMS sEMG was found in all muscles regarding the diagnosis of TMD at rest and in the suprahyoid muscles during MVC on parafilm. Moreover, sensitivity ranging from 71.3% to 80% and specificity from 60.5% to 76.6%. In contrast, RMS sEMG did not exhibit acceptable degrees of accuracy in the other masticatory muscles during MVC on parafilm. It was concluded that the RMS sEMG is a complementary tool for clinical diagnosis of the myogenous TMD.

Effect of upper thoracic manipulation on mouth opening and electromyographic activity of masticatory muscles in women with temporomandibular disorder: a randomized clinical trial.

OBJECTIVE: The purpose of this study was to assess the effect of upper thoracic manipulation on vertical mouth opening (VMO) and electromyographic activity of the masticatory muscles in women with temporomandibular disorder (TMD). METHODS: A randomized, controlled, blinded study involving 32 women (mean age of 24.78 ± 5.41 years) diagnosed with TMD was performed. Subjects were randomly allocated to an experimental group (n = 16) or a sham manipulation (placebo) group (n = 16). A single session of manipulation was administered to the T1 vertebral area. Electromyography was used to determine activity of masticatory muscles with the mandible at rest and during isometric contraction. Vertical mouth opening was measured using a ruler. Measurements were made before manipulation, immediately after manipulation, and at the short-term follow-up (2 to 4 days after manipulation). RESULTS: No significant differences were found in any of the comparisons of mandibular VMO or electromyographic activity of the masticatory muscles at rest or during isometric contraction of mandibular elevator muscles (P > .05). Regarding isometric contraction of the mandibular depressors, an immediate increase in muscle activity was found in the suprahyoid (P = .014) and left masseter (P = .005) muscles. CONCLUSION: In the present study, no significant differences were found regarding VMO between the experimental and placebo groups or among the different evaluations times in each group. Moreover, Cohen d test revealed no clinical effect of the technique. Therefore, based upon the findings of this study, manipulation administered to the T1 vertebral area appears to have no effect on VMO and electromyographic activity of the masticatory muscles in women with TMD.

Effects of upper thoracic manipulation on pressure pain sensitivity in women with temporomandibular disorder: a randomized, double-blind, clinical trial.

OBJECTIVE: The aim of the present study was to evaluate the effects of upper thoracic manipulation on pain in subjects with temporomandibular disorder. DESIGN: Thirty-two women with a diagnosis of temporomandibular disorder were randomly allocated to an experimental group (n = 16), submitted to upper thoracic manipulation, and a placebo group (n = 16), submitted to a procedure in the thoracic region with no therapeutic effect. All volunteers underwent an evaluation of pain in the masticatory muscles and the temporomandibular joint using an algometer and the visual analog scale before and immediately after the procedure as well as after 48-72 hrs. Two-way repeated-measures analysis of variance was used for the intragroup and intergroup analyses, with the level of significance set to 5% (P < 0.05). Cohen d was calculated for the determination of the effect size. RESULTS: No significant group-by-time interaction was found (P > 0.05) for algometry in any analysis, and Cohen d revealed no significant effect of the treatment. Moreover, no significant group-by-time interaction was found for facial pain intensity determined using the visual analog scale (P > 0.05), and Cohen d also revealed no significant effect of the treatment regarding this variable. CONCLUSIONS: On the basis of the present findings, upper thoracic spinal manipulation does not lead to a reduction in pain in women with temporomandibular disorder.