Hemimasticatory spasm: Clinical and electrophysiologic observations

Raymond G. Auger, William J. Litchy, Terrence L. Cascino, J. Eric Ahlskog

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Hemimasticatory spasm is a rare disorder of the trigeminal nerve that produces involuntary jaw closure due to paroxysmal unilateral contraction of jaw-closing muscles. We report three patients with this disorder. Electrophysiologic studies demonstrated normal blink and masseter reflexes. The masseter inhibitory reflex was absent during periods of spasm. Needle electromyography demonstrated irregular bursts of motor unit potentials that were identical to the pattern observed in hemifacial spasm. The electrophysiologic findings suggest ectopic excitation of the trigeminal motor root or its nucleus, an abnormality that is analogous to ectopic excitation of the facial nerve in hemifacial spasm. One patient improved temporarily with surgery, one improved while on treatment with carbamazepine, and another responded favorably to botulinum toxin injection.

Original languageEnglish (US)
Pages (from-to)2263-2266
Number of pages4
Issue number12
StatePublished - Dec 1992

ASJC Scopus subject areas

  • Clinical Neurology


Dive into the research topics of 'Hemimasticatory spasm: Clinical and electrophysiologic observations'. Together they form a unique fingerprint.

Cite this