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Objective To investigate changes of brainstem auditory evoked potential (BAEP)and somatosensory evoked potential (SEP) in patients with acute cerebral infarction,and discuss their relation with prognosis of the patients.Methods The study involved 60 patients with acute cerebral infarction.Changes of BAEP and SEP in each patient were detected and recorded continuously.Prognosis evaluation was performed by using GCS.Another 60 age-matched and gender-matched healthy human beings were enrolled as controls.Results Incubation period of BAEP wave Ⅰ had no significant difference between the cerebral infarction and control groups (P ＞ 0.05).However,interspike intervals of other BAEP waves in cerebral infarction group were different from those in control group (P ＜ 0.05).A series of waves of SEP (P14-N60) were all significantly prolonged in cerebral infarction group (P ＜0.05).Conclusion BAEP and SEP can effectively reflect function of brain stem in patients with acute cerebral infarction and have some values in determining their prognosis.
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Objective To explore the role of somatosensory evoked potentials elicited by paraspinal stimulation in the detection of spinal cord lesions.Methods Patients with clinically suspected spinal cord lesions underwent somatosensory evoked potentials(SEPs)and spinal cord conduction velocity(SCCV)test using paraspinal stimulating method.96 patients aged 15 to 75 years old with suspected spinal cord lesions of various aetiologies were tested.36 patients had demyelinating disease of the spinal cord,26 had sub-acute combined degeneration of the spinal cord,19 had myelopathy,10 had acute myelitis,5 had spinal cord corhpression.Results Paraspinal stimulation elicited somatosensory evoked potentials were Performed on all 96 patients,68 of whom underwent spinal MRI as well.SEPs and SCCV were found abnormal in a high ratio in all kinds of spinal cord lesions ; in general,78 among the 96 patients had abnormal SEPs with a sensitivity of 81.25%.27 out of 36 with demyelinating disease of the spine had abnormal SEPs with a sensitivity of 75.00%,23 out of 26 with subacute combined degeneration of the spinal cord had abnormal SEPs with a sensitivity of 88.46%,8 out of 10 with acute myelitis had abnormal SEPs,15 patients with myelopathy having abnormal findings,all 5 patients with spinal cord compression had abnormal SEPs.42 of 68 patients undergoing MRI revealed to be abnormal,in which 35 patients also had abnormal SEPs.The other 26 patients had normal spinal MRI,in which 21 patients had abnormal SEPs.Conclusions Paraspinal stimulation somatosensory evoked potentials and spinal cord conduction velocity may objectively document the abnormalities of electrophysiology,which occurs earlier than those of anatomy and radiological finds, therefore it may detect the dysfunction of spinal cord at an early stage.It is even more useful in the detecting of the metabolic myelopathy,which can hardly be detected by MRI.This technique is simple,inexpensive, and maybe useful in the diagnosis for patients with suspected spinal cord lesions.
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Objective To study the changes in somatosensory evoked potential caused by injection of adriamycin magnetic gelatin microspheres into subarachnoid space of rabbits. Methods Thirty rabbits were randomly divided into 5 groups: sham operation group (group S), gelatin microspheres 5mg (group C1), 15mg of gelatin microsphere (group C2) controlled groups, and adriamycin microspheres 5mg (group A1) and 15mg (group A2) groups. Under the effect of magnet, microspheres were injected into the subarachnoid space of rabbits. The pain threshold of electronic stimulation, motor function of rabbits′ hinder limbs and somatosensory evoked potential (SEP) were observed continuously. Results Obvious rise of pain threshold was found in group A2 (P
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Objective To study the feasibility and reliability of median nerve somatosensory evoked potential monitoring in neurosurgery around the brain stem. Methods in selected 43 patients SEP N20, waveforms were recorded after stimulation of left and right median nerves respectively. Anesthesia was maintained with intravenous anesthetics throughout the operation. As soon as N20 waveform changed significantly, the surgeon was informed and the operative procedure was modified whenever possible. Results SEP waveforms were almost stable during maintaining with total intravenous anesthesia (TIVA). Within 43 cases, SEP waveform of & patients significantly changed. In these cases, SEP of 5 patients returned to normal gradually and no further neurologic dysfunction happened postoperatively. The other 3 cases did not recover, and postoperative neurologic complications happened. There was no false-negative or false-positive result. The correlation between intraoperative SEP changes and postoperative neurologic alterations was significant statistically. Conclusions SEP recording is a reliable technique for intraoperative monitoring during neurosurgery around the brain stem. TIVA is helpful for SEP monitoring.