BODY POSITION EFFECTS ON EMG ACTIVITY OF STERNOCLEIDOMASTOID AND MASSETER MUSCLES IN PATIENTS WITH MYOGENIC CRANIO-CERVICAL-MANDIBULAR DYSFUNCTION

This study was conducted in older to determine the effects of body pos ition on integrated electromyographic (IEMG) activity of sternocleidom astoid and masseter muscles in 17 patients with myogenic cranio-cervic al-mandibular dysfunction. EMG recordings at rest and during swallowin g of saliva and maximal voluntary clenching were performed by placing surface electrodes on the sternocleidomastoid and masseter muscles (co ntralateral to the habitual side of sleeping of each patient), in the following body positions: standing, seated, supine, and lateral decubi tus position. Significant higher EMG, activities were recorded in the sternocleidomastoid muscle in the lateral decubitus position and in th e supine position (except during swallowing), whereas a significant hi gher EMG activity was recorded in the masseter muscle during maximal v oluntary clenching in standing and seated positions. The EMG pattern o bserved Suggests that the presence of parafunctional habits and body p osition could be closely correlated with the clinical symptomatology i n the sternocleidomastoid and masseter muscles at wakening and during waking hours. respectively, in patients with myogenic cranio cervical- mandibular dysfunction.