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Lateral spread response elicited by double stimulation in patients with hemifacial spasm
Author(s) -
Yamashita Shinya,
Kawaguchi Tadashi,
Fukuda Masafumi,
Suzuki Kenji,
Watanabe Masatoshi,
Tanaka Ryuichi,
Kameyama Shigeki
Publication year - 2002
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.10123
Subject(s) - hemifacial spasm , stimulation , facial nerve , orbicularis oculi muscle , facial muscles , electromyography , stimulus (psychology) , medicine , microvascular decompression , psychology , anesthesia , anatomy , neuroscience , surgery , eyelid , trigeminal neuralgia , psychotherapist
In patients with hemifacial spasm (HFS), a lateral spread response (or abnormal muscle response) is recorded from facial muscles after facial nerve stimulation. The origin of this response is not completely understood. We studied the lateral spread responses elicited by double stimulation in 12 patients with HFS during microvascular decompression. The response was recorded from the mentalis muscle by electrical stimulation of the temporal branch of the facial nerve or from the orbicularis oculi muscles by stimulation of the marginal mandibular branch. The interstimulus intervals (ISIs) of double stimulation ranged from 0.5 to 7.0 ms. R1 was defined as the response elicited by the first stimulus, and R2 as the response elicited by the second stimulus. R1 had a constant latency and amplitude regardless of the ISI, whereas R2 appeared after a fixed refractory period without facilitation or depression in a recovery curve of latency and amplitude. From these findings, we consider that the lateral spread response is due to cross‐transmission of facial nerve fibers at the site of vascular compression rather than arising from facial nerve motor neurons. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002