Hemimasticatory muscle spasm: an electromyogram analysis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the usefulness of electromyogram (EMG) in the diagnosis of the patients with hemimasticatory spasm (HMS).</p><p><b>METHODS</b>Four cases with HMS were reported. All the 4 patients were undertaken needle and surface electrode EMG examination.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>It is very important to use EMG for the diagnosis of HMS.</p>