Change of Magnetic Motor Evoked Potentials in Hemiparesis due to Cerebral Infarction

뇌경색에 의한 편측부전마비에서 자기운동유발전위의 변동

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.