1992 Fiscal Year Final Research Report Summary
Motor Evoked Potentials induced with Transcranial Magnetic Brain Stimulation
| Project/Area Number |
02454348
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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 |
Orthopaedic surgery
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| Research Institution | Kansai Medical University |
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Principal Investigator |
KAMEYAMA Osamu Kansai Med Univ, Dept. of Orthop. Surg, Associate professor, 医学部・整形外科, 助教授 (50148516)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Yoshiki Kansai Med Univ, Dept. of Orthop. Surg, Assistant professor, 医学部・整形外科, 講師 (30077755)
OGAWA Ryokei Kansai Med Univ, Dept. of Orthop. Surg, Professor, 医学部・整形外科, 教授 (90077610)
MORI Yoshiki Kansai Med Univ, Dept. of Orthop. Surg, Assistant professor (30077755)
MORI Yoshiki Kansai Med Univ, Dept. of Orthop. Surg, Assistant professor (30077755)
MORI Yoshiki Kansai Med Univ, Dept. of Orthop. Surg, Assistant professor (30077755)
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| Project Period (FY) |
1990 – 1992
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| Keywords | magnetic stimulation / motor cortex / evoked potential / spinal cord injury / conduction time / latency |
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| Research Abstract |
Motor evoked potentials (MEPs) induced by magnetic brain stimulation were investigated to clarify the usefulness for an acute spinal cord injury. 25 rabbits were employed for this acute spinal cord injured model. The MEPs from the tibialis anterior muscle (M-MEP) were recorded with bipolar electrodes : prior to the injury ; just immediately after the injury ; 30 min, 1 hour, 3 hours and 5 hours respectively after the injury. The MEPs from spinal cord (S-MEP) were recored at the proximal and distal part of the injured site with epidural tube electrodes. Subjects were divided into two groups ; complete and incomplete paralysis, according to the degree of motor dysfunction at 1 week after the injury. All of the subjects with incomplete paralysis showed the prolongation of the M-MEP latency and polyphasic wave form was seen, immediately after the trauma. Infiltration of the inflammatory cells and diffuse hemorrhage were seen at the gray matter in the injured spinal cord in the incomplete g
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roup. In compete paralysis cases, the M-MEP was disappeared within 3 hours and histopathologically, large area of the nerve cells were disappeared at the gray matter in this group. On the other hand, the S-MEP disappeared just after trauma in the group with complete paralysis as well as the incomplete paralysis group. This study indicated that the MEPs have some possibilities to detect the severity of the spinal cord injury and to evaluate of prognosis of motor function in patients with spinal cord injury at an acute phase.
In clinical study we have examined the MEPs in 35 normal subjects and 126 patients ; 67 cases with cervical spondylotic myelopathy ; 24 cases with spinal canal stenosis ; 35 cases with spinal cord injury. The stimulator coil was placed on the vertex and then the MEPs were evoked by transcranial motor cortex stimulation during relaxd position and during the remote muscle contraction. Special consideration was focused on the silent period after the MEPs during the maximum voluntary contraction of the target muscle. The results showed that the central motor conduction time correlated with the clinical evaluation in the myelopathy patients and that the abnormality of the conduction time was not observed in the spinal canal stenosis patients. During the maximum voluntary contraction of the target muscle, the consistent silent period was observed after the MEPs in the normal subjects, but this duration remarkably shortened in the myelopathy patients. Less
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