Proposal of surface electromyography signal acquisition protocols for masseter and temporalis muscles

Abstract

Introduction: The aim of this study was to propose a method of electrodes positioning on the superficial masseter and anterior temporalis muscles for surface electromyographic (sEMG) recordings in order to overcome some known methodological constraints. Methods: Fifteen volunteers with normal occlusion participated in two experimental sessions within a 7 day-period. Surface electrodes were placed on two different locations that were based on palpable and individual anatomical references. Surface EMG signals (2000 Hz per channel; A/D: 16 bits; gain: 2000 X; band-pass filter: 20-500 Hz) were recorded under three conditions: mandibular rest position, 30% and 100% of maximum voluntary bite force. Three measurements of maximal bite force were taken by using a force transducer positioned over the lower right first molar region and the highest record was taken into account. The root mean square value was considered for analysis. Intraclass correlation coefficients (ICCs), paired t test, and the Bland-Altman method comprised the statistical analyses. The level of significance was set at 0.05. Results: ICC records for right and left masseter and anterior temporalis muscles at T 0 (first sEMG record) and T 7 (second sEMG record) intervals were significantly different (p<0.05). The results showed satisfactory to excellent reproducibility of RMS values at rest, MVBF and 30% MVBF, as well as for MVBF in kgf. Conclusion: The results showed reliable reproducibility for the sEMG signal recording in masseter and anterior temporalis muscles from the protocols presented and under the three conditions investigated.

Atividade Eletromiográfica Dos Músculos Da Mastigação Em Indivíduos Com Mordida Cruzada Posterior / Electromyographic Activity of Masticatory Muscles in Patients With Posterior Crossbite

“…Apesar da EMGs ser um exame diagnóstico simples, é extremamente sensível 27 . Localizar, fixar e preparar a pele no local onde serão colocados os eletrodos são, por exemplo, aspectos fundamentais para que a captura do sinal eletromiográfico sofra mínima interferência 6,28 .…”

“…Sabaneeff et al 28 Figura 1 -Fotografias que ilustram as referências anatômicas para posicionamento de eletrodos nos músculos temporal anterior e masseter superficial: A: Visão lateral do crânio; B: Visão lateral de peça anatômica mostrando os planos faciais profundos com visibilidade dos respectivos músculos e sua relação com as estruturas anatômicas.…”

“…Legenda: Linha TLV: proeminência óssea formada pelo processo zigomático do osso frontal com o processo frontal do osso zigomático; linha TLH: superfície superior do arco zigomático; Go: ponto Gônio; linha ML: união do ponto Go marcado sobre o tecido mole à metade da distância da borda póstero-inferior do osso zigomático ao arco zigomático, ambos localizados por palpação; Fonte: Sabaneeff et al 28 Os eletrodos são posicionados ao longo da linha ML, que representa a linha de ação do músculo masseter, com o ponto de contato entre ambos localizado sobre a marcação de 40% do comprimento total de ML para evitar a sua área tendinosa. A aquisição, a amplificação, assim como a filtragem do sinal são igualmente importantes para que haja uma padronização no processamento de dados 6 Para Iodice et al 9 , a elevada heterogeneidade metodológica e a falta de critérios padronizados na avaliação eletromiográfica dificulta a comparação dos resultados entre os diferentes estudos, assim como a reprodutibilidade dos mesmos.…”

Standing Up from a Chair with an Asymmetrical Initial Foot Position Decreases Trunk and Masticatory Muscle Activities in Healthy Young Men

“…Adhesive pre-gelled Ag/AgCl surface EMG electrodes (Delsys Inc., Boston, MA, USA) were placed on six trunk and lower limb muscles (rectus abdominis (RA), erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius lateral head (GA)) and four additional muscles (temporalis (TE), masseter (MA), sternocleidomastoid (SCM), and upper trapezius (UT)), all on the dominant side. The positioning of the electrodes was as described previously [ 20 , 21 , 22 ].…”

Short-term changes in muscle activity and jaw movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry

“…The reference point was identified at 40% of the length of the muscle line from Go. The electrodes for TA were placed just above the upper edge of the zygomatic arch, posterior to the vertical line (the bony prominence formed by the zygomatic process of the frontal bone and the posterior limit of the frontal process of the zygomatic bone), and anterior to the scalp 18…”