1994 Fiscal Year Final Research Report Summary
A Cinical and a fundamental study of the efficacy and the safety of Transcraniol Magnetic Stimmulation on facial movement disorders.
| Project/Area Number |
04454428
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Ymagata University |
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Principal Investigator |
AOYAGI Masaru Yamagata univ.Dept.of Otolaryngology, School of Medicine.Professor, 医学部, 教授 (40107181)
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| Co-Investigator(Kenkyū-buntansha) |
INAMURA Hiroo Yamagata univ.Dept.of Otolaryngology, School of Medicine.Professor, 医学部, 助手 (50213129)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Magnetic stimulation / Facial nerve / Facial nerve palsy / Facial movement disorders / Evoked EMG |
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| Research Abstract |
For an early prognostic diagnosis of patients with peripheral facial palsy, a magnetic stimulator (Dantec Mag 2) was used to directly stimulate the intracranial portion of the facial nerve in 15 normal subjects and 108 patients with peripheral facial palsy.
In normal subjects and patients with facial palsy, compound muscle action potentials (CMAPs) of the orbicularis oris muscle elicited by transcranial magnetic stimulation were compared with CMAPs elicited by electrical stimulation at the peripheral site of the stylomastoid foramen which is similar to electroneurography (ENoG) and regularly used in our department. In normal subjects, the latency of magnetically evoked CMAPs was longer (1.0 ms, SD 0.39 ms) than that of CMAPs evoked by electrical stimulation.
In patients, ENoG Values declined until the seventh day after onset of palsy, and then plateaued. However, the amplitude ratio of maganetically evoked CMAPs between the affected side and normal side showed no tendency to decline unti
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l the seventh day after onset of palsy. So, whether magnetically evoked CMAPs could be recorded must be discussed in relation to the prognosis for facial palsy. The patients whom magnetically evoked CMAPs could be recorded within the seventh day after onset of palsy were classified in a group in which the minimal ENoG value was greater than 20%. Those patients recovered almost 2 months after the onset of palsy, and were significantly better than their recovery rates those of the patients in whom magnetically evoked CMAPs could not be recorded.
The site at which the facial nerve is magnetically stimulated remains controversial. In patients whth peripheral facial palsy, recovery of stapedial reflex, blink reflex and magnetically evoked CMAPs were examined to investigate the site of magnetic stimulation. From the clinical perspective, the facial nerve is thought to be magnetically stimulated near the meatal foramen which is thought to be the damage site in Bell's palsy. This stimulation site was almost the same point as that calculated from the mean latency difference between magnetically evoked CMAPs and ENoG in normal controls.
No harmful effects were seen during the magnetic stimulation test. Accordingly, the efficacy of this test was demonstrated. Less
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