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P332 Effect of treatment with U-74389G and methylprednisolon on somatosensory evoked potentials in the mild compression rat spinal cord
Poster Session: Sensor), Evoked Potentials (AEP, VEP, SEx°) with Parkinson syndrome (the age ranged from 49-75 yr, the mean age 68 yr). SEP and VEP changes mainly showed amplitude reduction (p 0.001) of the evoked responses without significant changes in latency. SEP and VEP abnormalities were correlated by the clinical findings and severity of the disease. SEPs were remarkable that point to the early involvement of somatosensory system, while VEPs were changed in the more advanced cases. TSC (Magtrim 200, Novametrix) was delivered through 9.5 cm coil centred over C3 or C4, with MEP registration from ABM and tibial anterior in 13 of these patients, and in 6 of them MEP latency shortening was found, while in the others the finding was normal. In patients with unilateral Parkinson syndrome the cerebral evoked potentials and MEP showed asymmetry in the amplitude reduction, and latency shortening on the side of the lesion, respectively.
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POSTrRAUMATIC VISUAL ABNORMALITIES WITH VISUAL EVOKED POTENTIALS
N. Isik, N.C. Isik, M. Kalelioglu, M. Sarier, I.M. Unat, I. Ktseoglu.
Gtztepe Hospital Neurology and Neurosurgery depts., IstanbuL Turkey The visual pathway is vulnerable to injury from the cornea to the calcarine cortex. Large series of cases of closed head injury have shown a 0.5% to 1.5% incidence of visual impairment resulting from damage to the optic nerve and chiasm. The diagnosis is even more difficult in an unconscious patient. Radiograms, CT scans and MRI are helpful to diagnose. Visual evoked potentials (VEPs) are reliable indicator of the integrity of the visual pathway. There are two treatment modalities (surgical optic nerve decompression and medical therapy with methyl-prednisolone). The management of injury to the optic nerve is still controversial and pathogenesis is not clearly understood. Four patients with posttraumatic blindness are reported. One of cases had bilateral lesions. All of the cases had abnormal visual evoked potentials. Radiograms, cranial CT scans, and MRI findings were normal. We did not perform any optic nerve decompression, we used methyl-prednisolone therapy. Only one of the cases had partial visual recovery. We evaluated the role of pattern-VEPs in predicting outcome of visual recovery in these patients.
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THE MIDDLE LATENCY AUDITORY EVOKED POTENTIALS IN PARKINSON'S DISEASE (PRELIMINARY REPORT)
M. t~elik, H. Sucu, F. Kiymaz-Seleker, B. Oflazo~lu, H. Form.
Department of Neurology ~i~li Effal Hospital ]stanbul Turkey Abnormalities of PI component of middle latency auditory evoked potentials (MLAEPs) are reported in dementia which is suggested to be due to cholinergic disfunction. The aim of our study was to investigate the MLAEP changes in demented and nondemented patients with Parkinson's disease. 16 healthy controls and 15 patients were included in the study. Patients were evaluated with repeated neurologic examinations and imaging studies. Mini mental state examination (MMSE) was administered to all patients and subjects. Non of the patients received anticholinergic drugs. The MLAEPs were recorded while the patients were in an alert state, using the Cz electrode referenced to A1. Rarefaction click stimuli were delivered binaurally at a rate of 1/sec, with a stimulus intensity of 55 dB above threshold. P1 component of MLAEP's could be recorded in all controls with a mean latency of 51.11 4- 4.1 msec (41-56.6 msec) and amplitude values between 0.3-5.69 #V. In three patients with MMSE scores of 28, 24 and 19 P1 were absent. The other 12 patients, 2 of whom with MMSE scores 20 and 22 and 10 with MMSE scores 28 or above had normal P1 values. We suggested that dementia is not the only determinant of abnormal P1 in Parkinson's disease.
EFFECT OF TREATMENT WITH U-74389G AND METHYLPREDNISOLON ON SOMATOSENSORY EVOKED POTENTIALS IN THE MILD COMPRESSION RAT SPINAL CORD M. Harat, J. Kochanowski. Military" High School of Medicine, Ltdz,
Poland The purpose of this investigation was comparison effects of treatment with
357
methylprednisolon (MP) and U-74389G - the compound of lazaroids on compressed rat spinal cord. The spinal cord function was monitoring by somatosensory evoked potentials (SEPs). The compression was achieved by mild blocking-weight model. Forty five adult male Wistar rats were anesthetized and the laminectomy at the T h g - T h l 0 level was performed. Animals with the same SEPs pattern before and after laminectomy were blindly allocated to one of three groups (fifteen rats in each). The weight of 14.8 g was applied on the spinal cord extraduraly for 60 minutes. The SEPs were recorded during all the time of compression. The rats received the treatment intravenously in single dose 2 minutes after start the compression. The time when the isoelectric line appear was assessed, if the SEPs pattern did not disappear the amplitude of the most stable and significant component of rats SEPs (N1P1) was measured. The time when the isoelectric line appear in each group was analyzed statistically. The proportional reduction of amplitude N1P1 was statistically analyzed and the groups were compared by Wilcoxon test. The time of isoelectric line appearing was statistically significant at p, 0.001 between control group and group with MP and between control group and group with U-74389G. The time of isoelectric line appearing was not significant at p.0.05 between group with MP and group with U-74389G. The proportional reduction of amplitude N1P1 was significant at p.0.001 between control group and group with MP and between control group and group with U-74389G. The proportional reduction of amplitude N1P1 was not significant at p. 0.05 between group with MP and group with U-74389G protect the spinal cord function during mild compression. We did not achieved statistically significant differences of protecting action on mild compressed spinal cord between MP and U-74389G.
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ELECTROPHYSIOLOGICAL INVESTIGATIONS OF THE MILD SPINAL CORD INJURY ON THE RATS EXPERIMENTAL MODEL
J. Kochanowski, M. Harat. Military High School of Medicine, Ltdz,
Poland Somatosensory evoked potentials (SEPs) waveform recorded from the normal spinal cord were described. A mild compression spinal cord injury was performed in two experimental models. The first model was used to assess the disappearing and second one was used to assess the returning of the electrophysiological spinal cord function after injury. The evolution of SEPs waveform was evaluated. In the first experimental model authors described typical changes in waveforms morphology from normal to isoelectric line during spinal cord compression. In the second model a isoelectric line was achieved by more severe but short time compression and the typical changes SEPs morphology after decompression were described. Authors achieved evidences that spinal cord function can early return after decompression and can disappear gradually during mild compression but the point of this work are the electrophysiological evidences that a cascade of secondary injury mechanism may deteriorated spinal cord function even after mild compression in one hour after decompression.
N13 POTENTIAL IN BRAIN DEATH A. Traba, R. Roldfin, A. Esteban. Hospital General Universitario
Gregorio Marah6n, Madrid, Espaha The cervical response of somatosensory evoked potentials (SEP) to median nerve stimulation has been analyzed in patients with brain death (BD). Our aim is to demonstrate the mixed nature of N13 potential when it is registered with cephalic reference, with two components of spinal and brainstem (BS) origin; to demonstrate its dissociation in absence of BS function and, finally, to establish its usefulness for BD diagnosis. The study was carried out on 19 patients with clinical and neurophysiological BD criteria and on a normal control group of 12 subjects. The potentials were obtained with Cv6--7 active electrode and Fz and anterior cervical (AC) references. In the normal group, the substraction of Cv7-AC (N13) response from Cv7-Fz ("N 13") provoked a "N 13" reduction by elimination of spinal origin component and, in this way, the component with probable BS origin was identified. In 17 patients there was cervical response that could be seen with both references. In all the cases, the substraction of the potentials caused the complete "N13" elimination, which demonstrates the absence of BS component in these patients. In 2 cases SEP were obtained before establishing BD and, in the substraction, there was a potential
[-P-~
POSTrRAUMATIC VISUAL ABNORMALITIES WITH VISUAL EVOKED POTENTIALS
N. Isik, N.C. Isik, M. Kalelioglu, M. Sarier, I.M. Unat, I. Ktseoglu.
Gtztepe Hospital Neurology and Neurosurgery depts., IstanbuL Turkey The visual pathway is vulnerable to injury from the cornea to the calcarine cortex. Large series of cases of closed head injury have shown a 0.5% to 1.5% incidence of visual impairment resulting from damage to the optic nerve and chiasm. The diagnosis is even more difficult in an unconscious patient. Radiograms, CT scans and MRI are helpful to diagnose. Visual evoked potentials (VEPs) are reliable indicator of the integrity of the visual pathway. There are two treatment modalities (surgical optic nerve decompression and medical therapy with methyl-prednisolone). The management of injury to the optic nerve is still controversial and pathogenesis is not clearly understood. Four patients with posttraumatic blindness are reported. One of cases had bilateral lesions. All of the cases had abnormal visual evoked potentials. Radiograms, cranial CT scans, and MRI findings were normal. We did not perform any optic nerve decompression, we used methyl-prednisolone therapy. Only one of the cases had partial visual recovery. We evaluated the role of pattern-VEPs in predicting outcome of visual recovery in these patients.
[-P-~
THE MIDDLE LATENCY AUDITORY EVOKED POTENTIALS IN PARKINSON'S DISEASE (PRELIMINARY REPORT)
M. t~elik, H. Sucu, F. Kiymaz-Seleker, B. Oflazo~lu, H. Form.
Department of Neurology ~i~li Effal Hospital ]stanbul Turkey Abnormalities of PI component of middle latency auditory evoked potentials (MLAEPs) are reported in dementia which is suggested to be due to cholinergic disfunction. The aim of our study was to investigate the MLAEP changes in demented and nondemented patients with Parkinson's disease. 16 healthy controls and 15 patients were included in the study. Patients were evaluated with repeated neurologic examinations and imaging studies. Mini mental state examination (MMSE) was administered to all patients and subjects. Non of the patients received anticholinergic drugs. The MLAEPs were recorded while the patients were in an alert state, using the Cz electrode referenced to A1. Rarefaction click stimuli were delivered binaurally at a rate of 1/sec, with a stimulus intensity of 55 dB above threshold. P1 component of MLAEP's could be recorded in all controls with a mean latency of 51.11 4- 4.1 msec (41-56.6 msec) and amplitude values between 0.3-5.69 #V. In three patients with MMSE scores of 28, 24 and 19 P1 were absent. The other 12 patients, 2 of whom with MMSE scores 20 and 22 and 10 with MMSE scores 28 or above had normal P1 values. We suggested that dementia is not the only determinant of abnormal P1 in Parkinson's disease.
EFFECT OF TREATMENT WITH U-74389G AND METHYLPREDNISOLON ON SOMATOSENSORY EVOKED POTENTIALS IN THE MILD COMPRESSION RAT SPINAL CORD M. Harat, J. Kochanowski. Military" High School of Medicine, Ltdz,
Poland The purpose of this investigation was comparison effects of treatment with
357
methylprednisolon (MP) and U-74389G - the compound of lazaroids on compressed rat spinal cord. The spinal cord function was monitoring by somatosensory evoked potentials (SEPs). The compression was achieved by mild blocking-weight model. Forty five adult male Wistar rats were anesthetized and the laminectomy at the T h g - T h l 0 level was performed. Animals with the same SEPs pattern before and after laminectomy were blindly allocated to one of three groups (fifteen rats in each). The weight of 14.8 g was applied on the spinal cord extraduraly for 60 minutes. The SEPs were recorded during all the time of compression. The rats received the treatment intravenously in single dose 2 minutes after start the compression. The time when the isoelectric line appear was assessed, if the SEPs pattern did not disappear the amplitude of the most stable and significant component of rats SEPs (N1P1) was measured. The time when the isoelectric line appear in each group was analyzed statistically. The proportional reduction of amplitude N1P1 was statistically analyzed and the groups were compared by Wilcoxon test. The time of isoelectric line appearing was statistically significant at p, 0.001 between control group and group with MP and between control group and group with U-74389G. The time of isoelectric line appearing was not significant at p.0.05 between group with MP and group with U-74389G. The proportional reduction of amplitude N1P1 was significant at p.0.001 between control group and group with MP and between control group and group with U-74389G. The proportional reduction of amplitude N1P1 was not significant at p. 0.05 between group with MP and group with U-74389G protect the spinal cord function during mild compression. We did not achieved statistically significant differences of protecting action on mild compressed spinal cord between MP and U-74389G.
~-3-~
ELECTROPHYSIOLOGICAL INVESTIGATIONS OF THE MILD SPINAL CORD INJURY ON THE RATS EXPERIMENTAL MODEL
J. Kochanowski, M. Harat. Military High School of Medicine, Ltdz,
Poland Somatosensory evoked potentials (SEPs) waveform recorded from the normal spinal cord were described. A mild compression spinal cord injury was performed in two experimental models. The first model was used to assess the disappearing and second one was used to assess the returning of the electrophysiological spinal cord function after injury. The evolution of SEPs waveform was evaluated. In the first experimental model authors described typical changes in waveforms morphology from normal to isoelectric line during spinal cord compression. In the second model a isoelectric line was achieved by more severe but short time compression and the typical changes SEPs morphology after decompression were described. Authors achieved evidences that spinal cord function can early return after decompression and can disappear gradually during mild compression but the point of this work are the electrophysiological evidences that a cascade of secondary injury mechanism may deteriorated spinal cord function even after mild compression in one hour after decompression.
N13 POTENTIAL IN BRAIN DEATH A. Traba, R. Roldfin, A. Esteban. Hospital General Universitario
Gregorio Marah6n, Madrid, Espaha The cervical response of somatosensory evoked potentials (SEP) to median nerve stimulation has been analyzed in patients with brain death (BD). Our aim is to demonstrate the mixed nature of N13 potential when it is registered with cephalic reference, with two components of spinal and brainstem (BS) origin; to demonstrate its dissociation in absence of BS function and, finally, to establish its usefulness for BD diagnosis. The study was carried out on 19 patients with clinical and neurophysiological BD criteria and on a normal control group of 12 subjects. The potentials were obtained with Cv6--7 active electrode and Fz and anterior cervical (AC) references. In the normal group, the substraction of Cv7-AC (N13) response from Cv7-Fz ("N 13") provoked a "N 13" reduction by elimination of spinal origin component and, in this way, the component with probable BS origin was identified. In 17 patients there was cervical response that could be seen with both references. In all the cases, the substraction of the potentials caused the complete "N13" elimination, which demonstrates the absence of BS component in these patients. In 2 cases SEP were obtained before establishing BD and, in the substraction, there was a potential