Background
and Purpose : Brainstem auditory evoked potentials(BAEPs) are responses of the brainstem by auditory stimulation. Vertebrobasilar transient ischemic attacks is the disease that occurs by insufficient circulation in the region of brainstem. The purpose of this study is to know the factors influencing the changes of BAEPs in vertebrobasilar transient ischemic attacks. Methods : The subject of study was 96 patients diagnosed as vertebrobasilar transient ischemic attacks. Patients were divided into two groups according to the BAEPs findings, age, sex, presence of hypertension, diabetes, hyperlipidemia, heart disease, neurologic findings, previous stroke, previous stroke, previous vertebrobasilar transient ischemic attacks, smoking and alcohol drinking, and time period between symptom onset and testing were compared. Results : There were no significant differences in age, sex, and presence of hypertension, diabetes, hyperlipidemia, heart disease, previous stroke history, previous vertebrobasilar transient ischemic attack, smoking, and alcohol drinking between two groups. The presence of abnormal neurologic findings in the first examination and time period between symptom onset and testing were significantly different between normal BAEPs group and abnormal BAEPs one(P < 005). Conclusions : The factors influencing the changes of BAEPs were presence of abnormal neurologic findings and time period between symptom onset and testing. These finding suggest that BAEPs test should be performed in acute stage of ischemic attack.

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 I 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 follow-up after 14 days after symptoms 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 group-normal, delayed, and no evoked MEP groups. Results : The CMCT in hemiparetic side of acute ischemic stroke patients were significantly delayed (P < 0.05) compared with the control group. The CMCT of hemiparetic side in the follow-up study showed no significantly difference in comparison to the control group. The prognosis of motor improvement was better I 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.