Efeito da estimulação eletrica nervosa transcutanea sobre a atividade eletromiografica dos musculos da mastigação em individuos portadores de desordem temporomandibular

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Temporomandibular disorder (TMD) is characterized by severa I signs and symptoms, among which are pain and changes in the electromyographic activity of the masticatory muscles. Thus, the objective of this work, which is composed of two articles, is 1) to identífy the alterations in the electromyographic activity of TMD individuais at rest and isometry situations and evaluate the effect of the transcutaneous electric nerve stimulation (TENS) on the pain and the electromyographic activity in the situations mentioned above; and 2) to detect the alterations in the activation pattern of the masticatory muscles of TMD individuais and evaluate the effect of TENS in this situation. For this, forty female volunteers were selected: twenty with TMD (x=23.04 f 3.5) - the study group - and twenty normal individuais (x=23.3 f 3) - the control group. TENS (symmetrical biphasic quadratic pulse, 150 Hz, 20 f-ls, pleasant intensity, frequency modulation-50%) was applied once to each group for 45 minutes. The electromyographic exam (EMG) data, collected by a data acquisition system (MCS-V2 Signal Conditioner by Lynx Tecnologia Eletronica Ltd.) with surface electrodes (active differential probes by Lynx Tecnologia Eletronica Ltd.) and visual analog scale (V AS) , was done before and immediately after TENS application. The EMG signal was analyzed by the RMS of the isometric and resting contractions, and the muscular activation pattern, by the normalized linear envelope of the isotonic contraction. In order to evaluate the effect of TENS on the RMS, the T test was performed for paired data. V AS was analyzed by the same test. Results showed that, at rest, TMD individuais had an increase in the EMG activity of the jaw elevator muscles, when compared to the control group. In the isometry, no difference was observed betvyeen the control and the study groups. TENS reduced the pain, the EMG activity the anterior portion of the temporal muscle at rest and increased the activity of the masseter muscles during isometry. We also observed that TMD individuais had an alteration in the activation pattern of the studied muscles, in comparison to the control group, and that TENS reversed this pattern. With the presented results, we can conclude that a single TENS application is effective for pain reduction and for changing the activation pattern of the masticatory muscles. Nonetheless, at rest and during isometry it does not act homogeneously on the evaluated muscles

ASSUNTO(S)

eletromiografia dor

ACESSO AO ARTIGO

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