Body position effects on EMG activity of the temporal and suprahyoid muscles in healthy subjects and in patients with myogenic cranio-cervical-mandibular dysfunction

This study was conducted in order to determine the effects of body position on integrated electromyographic (IEMG) activity of anterior temporal and s uprahyoid muscles, The study was performed on 15 patients with myogenic cra niocervical-mandibular dysfunction (CMD) and 15 healthy subjects. IEMG reco rdings at rest and during swallowing of saliva and maximal voluntary clench ing were performed by placing surface electrodes on the anterior temporal a nd suprahyoid muscles in the following body positions: standing, seated, su pine, and lateral decubitus position, Insignificant changes in IEMG activit y of both muscles were observed upon variations in the body position. Insig nificant differences in IEMG activity were observed between patients with m yogenic CMD and healthy subjects. A pattern of higher IEMG at rest and duri ng swallowing of saliva was observed in the suprahyoid muscles than in the anterior temporal muscles, whereas during maximal clenching activity, an op posite pattern was observed. Results of the present study seem to suggest t hat for the anterior temporal and suprahyoid muscles there is no specific b ody position that could be relevant to initiate and/or to perpetuate a cran iomandibular dysfunction.