Related Experiment Videos
Hemimasticatory spasm: clinical and electrophysiologic observations
R G Auger1, W J Litchy, T L Cascino
1Department of Neurology, Mayo Clinic, Rochester, MN 55905.
Neurology
|December 1, 1992
Summary
Hemimasticatory spasm, a rare trigeminal nerve disorder, involves involuntary jaw closure. Electrophysiology suggests ectopic excitation, with treatments like carbamazepine, botulinum toxin, and surgery showing potential benefits.
Area of Science:
- Neurology
- Neurophysiology
Background:
- Hemimasticatory spasm is a rare trigeminal nerve disorder characterized by involuntary jaw closure.
- It results from paroxysmal, unilateral contraction of jaw-closing muscles.
Observation:
- This report details three patients diagnosed with hemimasticatory spasm.
- Electrophysiologic studies revealed normal blink and masseter reflexes but an absent masseter inhibitory reflex during spasms.
- Needle electromyography showed motor unit potential bursts similar to hemifacial spasm.
Findings:
- Electrophysiologic findings suggest ectopic excitation of the trigeminal motor root or nucleus.
- This mechanism is analogous to the ectopic excitation seen in hemifacial spasm.
Implications:
- The findings provide insights into the pathophysiology of hemimasticatory spasm.
- Therapeutic interventions including carbamazepine, botulinum toxin injection, and surgery demonstrated varying degrees of patient improvement.