Electromyography of masticatory muscles in craniomandibular disorders

Patients presenting to the otolaryngologist with complaints such as otalgia, dizziness, tinnitus, or fullness in the ear may be experiencing the effects of craniomandibular disorders. These disorders can involve dysfunction in the delicate interrelationship of the skull, mandible, cervical vertebrae, and neuromuscular apparatus and can present as myofacial pain. Electromyographic recordings using surface electrodes were made bilaterally on the masseter, anterior temporalis, and digastric muscles in 641 craniomandibular patients, before and after transcutaneous electrical neural stimulation, at their initial presentation and following the insertion of mandibular orthopedic appliances. In the presenting patient, muscle-resting levels significantly decreased from hyperactive levels with transcutaneous electrical neural stimulation therapy. The creation of a new occlusal position with an orthotic appliance was found to correlate with a significant reduction in otolaryngologic symptoms as well as an increase in maximum muscle activity in function and coordination of muscle groups during mandibular movement. Thus, clinical electromyographic studies are an important aid in the treatment of craniomandibular disorders.