Related Experiment Video
Updated: Apr 26, 2026

Extraction of the EPP Component from the Surface EMG
Published on: December 17, 2009
[Hemimasticatory muscle spasm: an electromyogram analysis]
Yu-wei Wang1, Xu-chen Ma, Zhen-kang Zhang
1Department of Temporomandibular Joint Disorder and Orofacial Pain, Peking University School of Stomatology, Beijing 100081, China.
Objective:
To investigate the usefulness of electromyogram (EMG) in the diagnosis of the patients with hemimasticatory spasm (HMS).
Methods:
Four cases with HMS were reported. All the 4 patients were undertaken needle and surface electrode EMG examination.
Results:
Needle electrode EMG of the 4 patients with HMS showed grouped potentials synchronously with the onset of the spasm, which indicated abnormal excitatory electrical activities of the trigeminal nerve resulting in involuntary masticatory muscle movements.
Conclusion:
It is very important to use EMG for the diagnosis of HMS.
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