Long-latency response to transcranial magnetic stimulation in patients with hemifacial spasm

Atsuhiro Kojima, Takayuki Ohira, Moriichiro Takase, Kawase Takeshi Kawase

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Objective: We studied the long-latency response of the orbicularis oris muscle elicited with transcranial magnetic stimulation in patients with hemifacial spasm (HFS) and evaluated the excitability of the facial nucleus. Methods: We compared the thresholds on both sides in 8 normal volunteers and 7 patients with hemifacial spasm. The thresholds were determined as the lowest intensity required to produce motor evoked potentials with an amplitude of at least 50 μV in the orbicularis oris muscle. Average values were given as means±standard deviation. Wilcoxon's rank sum test was used for comparisons between the sides of normal subjects and of patients with HFS with respect to the threshold stimulus. Results: There was no significant difference between the thresholds on the two sides of the normal subjects (mean 1.88±5.30%, P>0.05). In patients with HFS, there was a significant difference between the thresholds on the spasm side and the normal side (mean 20.7±13.0%, P<0 05) In one patient studied after MVD, the difference between both sides disappeared. Conclusion: The difference between the thresholds in patients with HFS and the normalization in threshold after MVD suggested that the mechanism of HFS was hyperexcitability of the facial nucleus. Copyright (C) 1998 Elsevier Science Ireland Ltd.

Original languageEnglish
Pages (from-to)285-289
Number of pages5
JournalElectroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
Volume109
Issue number4
DOIs
Publication statusPublished - 1998 Aug 1

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Keywords

  • Facial nucleus
  • Hemifacial spasm
  • Hyperexcitability
  • Long-latency response
  • Magnetic stimulation
  • Threshold

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology

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