Surface intraoral genioglossus EMG recording technique for kinesiologic studies.

Electromyographic (EMG) recordings from intraoral genioglossus surface electrodes were compared to fine-wire recordings of the left genioglossus muscle during selected activities that involved (1) rest, (2) tongue protrusion without resistance, (3) isometric tongue protrusion, (4) jaw opening without resistance, (5) isometric jaw opening, and (6) swallowing. Right and left lateral protrusions of the tongue were evaluated also. Recordings from both surface and fine-wire configurations showed similar onset times, relative amplitude changes, and cessation times of EMG activity during unresisted tongue protrusion and isometric tongue protrusion. Swallowing EMG activity occurred somewhat earlier and was longer in duration in the surface electrode recordings than the fine-wire recordings; however, maximum amplitudes occurred at similar times. Neither type of electrode recorded significant EMG activity during jaw opening or isometric jaw opening. These findings support the validity of recording EMG activity of the genioglossus muscle by surface recording electrodes supported by an acrylic appliance. The development of such an appliance may be an important biofeedback tool to control genioglossus activity during such activities as tongue thrusting.