Electromyography of genioglossus and geniohyoid muscles during deglutition

An electromyographic investigation of the activity of the paired genioglossus and geniohyoid muscles of twenty-six human subjects during deglutition revealed a general pattern of muscular activity involving an initial build-up, gradual summation, and tapering of electrical potentials during swallowing of both saliva and water. There is an observable difference in the pattern of swallowing of individuals within a group and among the individual swallows of a single subject. There are longer periods of electrical activity during a saliva swallow than during a water swallow. The type of bolus also seems to affect the pattern of activity in the individual muscles as well as the length of time that they are working. The geniohyoid muscles do not appear to begin their activity with the genioglossus muscles but rather lag behind and they do not appear to be active for as long. Both pairs of muscles appear to remain active during and after the time that the bolus has passed the area of the laryngopharynx. A period of electrical silence occurs prior to the characteristic burst of activity associated with a swallow. This appears to be the result of an active inhibition.