Electromyographic responses from the stimulation of the temporalis muscle through facial acupuncture points

Abstract 

Objective

This study measured the electromyographic (EMG) responses of the temporalis muscle to electrical stimulation at 10 acupuncture points (acupoints) of the face and assessed whether electrical stimulation of these acupoints may improve the rhythmic activity of the muscles that open and close the jaw.

Methods

Fifty healthy adults clenched 2 thin pieces of wood between their teeth and kept a constant bite force for 30 seconds. The left anterior temporalis muscle was chosen for spontaneous EMG stimulation and recording.

Results

The mean EMG responses were positive at 10 points in early reflexes but negative at points Jiache, Chengjiang, and Dicang for late reflexes. No statistically significant difference was observed in the responses between age and stimulation intensity for both areas, but a significant inverse correlation existed between the distance from the acupoint to the recording electrode and the response.

Conclusion

This study showed that the surface electrical current applied to facial skin acupoints may excite or inhibit the anterior temporalis muscle via reflex pathways. The result from this stimulation may be applied to treat temporomandibular joint disorder occlusion of muscular origin.

Key indexing terms: Electromyography, Acupuncture, Temporalis muscle, Temporomandibular joint disorders, Muscles of mastication