• Korean Journal of Clinical Laboratory Science
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• v.47 no.1
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• pp.24-27
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• 2015

To measure motor evoked potentials (MEP) during emergency surgery is often difficult in patients with subarachnoid hemorrhage (SAH) from a ruptured cerebral aneurysm, The cause of these difficulties may be considered as damage to the motor pathway by hemorrhage. To identify the cause of difficulties in measuring MEP, we defined the association between motor evoked potentials during surgery and the severity of the hemorrhage in patients with subarachnoid hemorrhage.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.77-85
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• 2013

Intraoperative Neurophysiological Monitoring (INM) is very useful in monitoring the motorsensory pathway and vascular circulation system during intraspinal, or intracranial neurosurgery. Brainstem Auditory Evoked Potentials (BAEPs) are for detecting the problems along the auditory pathways including, the eighth cranial nerve and brainstem. Motor Evoked Potentials (MEPs) is a useful adjunct to conventional monitoring of Somato-sensory Evoked Potentials (SEPs) during surgery. Visual Evoked Potentials (VEPs) has been regarded as having limited significance for the preservation of visual function during neurosurgical procedures. In this paper, we propose that the most appropriate averaging of the number of inspections in the inspection of each used in the operative field, is good and efficient, functionally.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.414-419
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• 2016

A 35 years old woman presented with an acute meningeal syndrome following an intra ventricular haemorrhage without subarachnoid haemorrhage. The angiography demonstrated a 6 mm partially thrombosed saccular aneurysm at the plexal point of the right anterior choroidal artery (AChoA). It was surgically approached inside the ventricle through a trans-temporal corticotomy. The aneurysm was excised after distal exclusion of the feeding artery under motor-evoked potentials monitoring. Of the 19 cases of distal AChoA aneurysm neurosurgical treatment, this is the only one performed under electrophysiology monitoring, a simple and safe method to detect and prevent motor tract ischemia. We discuss this rare case, along with a comprehensible review of the literature of the previous surgical cases of distal AChoA aneurysms.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.2005-2011
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• 2020

Background: Motor imagery is the mental representation of an action without overt movement or muscle activation. However, few previous studies have demonstrated motor imagery training effects as an objective assessment tool in patients with early stroke. Objective: To investigate the effect of motor imagery training on Somatosensory Evoked Potentials (SSEP) and upper limb function of stroke patients. Design: A quasi-experimental study. Methods: Twenty-four patients with stroke were enrolled in this study. All subjects were assigned to the experimental or control group. All participants received traditional occupational therapy for 30 minutes, 5 times a week. The experimental group performed an additional task of motor imagery training (MIT) 20 minutes per day, 5 days a week, for 4 weeks. Both groups were assessed using the SSEP amplitude, Fugl-Meyer assessment of upper extremity (FMA UE) and Wolf motor function test. Results: After the intervention, the experimental group showed significant improvement in SSEP amplitude and FMA UE than did the control group. Conclusion: These findings suggest that the MIT effectively improve the SSEP and upper limb function of stroke patients.

• Annals of Clinical Neurophysiology
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• v.2 no.2
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• pp.107-113
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• 2000

Background & Objectives : Motor evoked potentials(MEPs) to magnetic trans cranial stimulation were performed to evaluate upper motor neuron involvement and relationship to lower motor neuron involvement in motor neuron disease patients. Method : MEPs were obtained in the 17 consecutive patients with motor neuron disease. These patients were divided into three group based on clinical evidence of upper and lower motor neuron involvement, bulbar symptom; amyotrophic lateral sclerosis(ALS), progressive muscular atrophy(PMA), progressive bulbar palsy(PBP). MEPs were recorded from abductor pollicis brevis and abductor hallucis muscles. Abnormal MEPs were defined by delayed central motor conduction time or absent MEP. Results : MEPs were abnormal in 64%(11/17) of patients; 100%(7/7) in ALS, 64%(4/7) in PMA, 0%(0/3) in PBP respectively. In 68 total recording muscles, 34 muscles had evidence of motor weakness and showed abnormal responses in 59%(20/34). Whereas 34 muscles with normal strength, only 3%(1/34) of muscles showed abnormal response. Conclusion : MEPs are well correlated with upper motor neuron signs in ALS and may detect masking upper motor neuron signs in PMA. The muscles with lower motor neuron sign(weakness) usually relate with abnormal MEPs reponses.

• The Journal of Internal Korean Medicine
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• v.28 no.3
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• pp.434-441
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• 2007

Objectives : Peripheral neurodegeneration occurs in diabetes mellitus (DM), both sensory and motor nerve. but we don't know exactly if DM affects central nerve pathway for all studies. Electrophysiologic study is one of the most important diagnostic tools for diabetic neuropathy. Electroneurography and electromyography are usually used. but evoked potentials (EP) is more sensitive to small nerve fiber damages and useful for central nerve evaluation in addition to peripheral nerves. Most diabetic neuropathy studies by EP have been performed with somatosensory evoked potentials (SSEP). In contrast, the objective of this study is to investigate if DM targets central motor neurons by assessing the relation between fasting blood sugar (FBS) and motor evoked potentials (MEP) latency. Methods : We inspected the medical records of 34 patients who had MEP tests during admitting days. The latency from cervical portion to abductor pollicis brevis was used as peripheral motor conduction time (PMCT). and the latency from vertex to cervical portion was used as central motor conduction time (CMCT). Then, they were correlated to FBS using correlation analysis. Results : There was a significant linear relation between FBS and PMCT (Pearson's correlation coefficient r=0.487, p<0.01), but a poor linear relation between FBS and CMCT (Pearson's correlation coefficient r=-0.l97. p>0.05). Conclusions : This study suggests that prolonged latencies of MEP in DM may be due to peripheral neuropathy rather than dysfunction of central motor pathway. therefore the clinical use of MEP to diabetic neuropathy has to be divided segmentally.

• Annals of Clinical Neurophysiology
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• v.24 no.1
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• pp.21-25
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• 2022

The newly identified frontal aslant tract (FAT) that connects the posterior Broca's area to the supplementary motor area is known to be involved in speech and language functions. We successfully intraoperatively monitored FAT using cortico-cortical evoked potentials generated by single-pulse electrical cortical stimulation in a patient with oligodendroglioma.

• Annals of Clinical Neurophysiology
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• v.1 no.2
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• pp.99-105
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• 1999

Background and Objectives : The Motor evoked potentials (MEP) study may be useful in the evaluation of the degree of impairment in the motor nervous system and in the determination of the prognosis. The purpose of this study is to evaluate the status of central nervous system in acute and subacute state of cerebral ischemia by comparing the changes of MEP in the initial and follow-up study. Methods : Twenty patients with hemiparesis caused by ischemic stroke were recruited for this study. We tested MEP within 7 days and followed-up after 14 days after symptom onset. The cerebral motor cortex area, cervical area for upper extremity and lumbar area for lower extremity were stimulated by transmagnetic stimulator. The central motor conduction time(CMCT) was measured with the difference in MEP caused by stimulating the vertical area and spinal area. The CMCT of hemiparetic patients were classified into three groups-normal, delayed, and no evoked MEP groups. Results : The CMCT in hemiparetic side of acute ischemic stroke patients were singnificantly delayed (P < 0.05) compared with the control group. The CMCT of hemiparetic side in the follow-up study showed no sinificantly difference in comparison to the control group. The prognosis of motor improvement was better in the groups of delayed MEP than the groups of no evoked MEP. Conclusion : The CMCT of hemiparetic and contralateral sides were delayed in acute ischemic stroke, compared with control group and were returned to normal boundaries in subacute state. But in the most cases with no MEP response in the initial study, also showed no MEP response in the follow-up study. The recovery occurred in the subacute state in cases with mild hemiparesis, whereas recovery did not occur in the subacute stage in case with severe hemiparesis.

• Annals of Clinical Neurophysiology
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• v.5 no.2
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• pp.187-191
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• 2003

Purpose: MEPs elicited by transmagnetic stimulations of the motor cortex are facilitated by voluntary muscle contraction. We evaluated the effects of the imagination of the movements on latencies of MEPs and reciprocal inhibition by using transmagnetic stimulations. Methods: Twenty two healthy volunteers(eight men and fourteen women) were studied. TMSs were delivered at rest and during imagining abducting or adducting right thumb. A stimulator with a round coil and a fixed intensity of 80% of maximum was used to evoke MEPs. MEPs were evoked by magnetic stimulations over the scalp and cervical spine(C7-T1), and central motor conduction times(CMCT) were calculated by subtracting the latency of compound muscle action potentials(CMAPs) obtained by stimulating over the cervical spine from that obtained by stimulating over the scalp. The motor evoked potentials were recorded from right abductor pollicis brevis muscle(APB) and adductor pollicis muscle(AP) simultaneously. Results: Imagination of abduction resulted in a shortened latency of the CMAPs in APB, and a prolonged latency in AP. Imagination of adduction resulted in a shortened latency in AP, and a prolonged latency in APB. But the imagination caused no significant change in the latency of CMAPs elicited by stimulation over cervical spine. Therefore, the changes of the CMCTs account for these latency changes with imagination of movement. With the imagination of abduction, there are significant reduction of the CMCT's in APB(10.8%) and prolongation in AP(5.8%). On the other hand, with the imagination of adduction, prolongation of the CMCT's in APB(7.3%) and reduction in AP(5.9%) were observed. Conclusion: These findings indicate that imagination of muscle contraction increases the excitability of the human corticospinal system. Reciprocal inhibition may be accountable for the prolonged latency in the antagonist muscle.

• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.158-162
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• 2006

Background: It has been proposed that proprioceptive input can modulate neural excitability in both primary motor cortices (M1) simultaneously, although direct evidence for this is still lacking. Previous studies showed that proprioceptive accuracy of one hand is reduced after the application of one-Hz repetitive transcranial magnetic stimulation (rTMS) for 15 minutes over the contralateral somatosensory cortex. The aim of this study was to investigate the effect of rTMS-induced central proprioceptive deafferentation to excitability of both M1 as reflected in ipsilateral and contralateral motor evoked potentials (MEP). Methods: MEPs of both abductor pollicis bravis (APB) muscles were recorded using single-pulse TMS over right M1 in seven healthy subjects. Immediately after one-Hz rTMS was applied for 15 minutes over the right somatosensory cortex, the MEP measurement was repeated. The proprioceptive function of the left thumb was assessed, before and after rTMS, using a position-matching task. Results: There was an increase in ipsilateral MEP after the rTMS: whereas no MEPs were recorded on the ipsilateral hand before the rTMS, MEPs were recorded in both ipsilateral and contralateral hand in three of seven subjects. At the same time, the mean log amplitude was reduced and the mean latency was prolonged in the contralateral MEP. Conclusions: rTMS-induced central proprioceptive deafferentation reduces the MEP generation in the contralateral hand, and fascilitates that in the ipsilateral hand. A further study with a larger sample seems warranted to confirm this finding and to elucidate the neurophysiology underlying it.