Effects of myogenous facial pain on muscle activity of head and neck.

This study evaluated the effects of visual input on surface electromyography (sEMG) of some stomathognatic and neck muscles (anterior temporalis, masseter, anterior digastric and sternocleidomastoid muscles) in patients experiencing myogenous facial pain compared with healthy volunteers. All subjects kept the mandible at rest with teeth apart and underwent a 15-s sEMG recording of anterior temporalis, masseter, digastric and sternocleidomastoid muscles. Each recording was carried out with closed and then open eyes. The sEMG activity of each muscle was compared between the two groups. In the study group, anterior temporalis, masseter and sternocleidomastoid sEMG with closed eyes showed higher values compared with controls (p<0.05). In the study group, left and right anterior temporalis (p<0.003) and right digastric (p<0.03) sEMG with open eyes showed higher values than sEMG with closed eyes. In the control group no significant differences were observed between closed and open eyes. In patients with myogenous facial pain, visual input appears to be associated with a significant increase in the sEMG activity of some head and neck muscles.