红藻酸致大鼠癫痫模型短潜伏期体感诱发电位分析

为了解癫痫发作时大脑神经元的功能状态,对红藻酸致痫大鼠发作前、发作期、发作间期经正中神经刺激短潜伏期体感诱发电位(SEP)进行了测定.结果表明:癫痫发作期其SEP的改变为N_1、P~1波的峰潜伏期(PL)延长,波幅(Amp)降低,有3例波形缺失.其机制分析与兴奋性氨基酸的神经无毒性作用及继发性缺血、缺氧致神经元损伤有关.     

The Effects of Spinal Cord Injury on Somatosensory Evoked Potentials Produced by Interactions Between Afferent Pathways

The purpose of the present study was to determine the utility of somatosensory evoked potentials (SEPs) produced by interaction between afferent pathways for spinal cord injury evaluation. Interaction was measured as alterations in SEP configuration compared to controls. Monkeys anesthetized with N₂O were used. Stimulus intensities were sufficient to excite all nerve fibers. The conditioning stimulus (CS) was applied to the left peroneal nerve and test stimulus (TS) to the left radial nerve. CS-TS intervals were 100 msec in duration. SEPs were recorded from primary cortical receiving area for the forelimb. Different surgical lesions were made at spinal cord level T₃-T₄. Amplitudes of TS-produced-SEPs remained unchanged postlesion. CS-produced-SEPs were found to be dependent upon the integrity of anterolateral column pathways. Accentuated interaction was observed following dorsal column ablation. Interaction was slightly enhanced after left hemisection but diminished after right hemisection or central cord lesion. Interaction between spatially separate afferent inputs as measured by SEP alteration was determined to be a sensitive indicator of spinal cord injury.     

A New Measure for Monitoring Intraoperative Somatosensory Evoked Potentials

ObjectiveTo propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study.MethodsThe proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included.ResultsWe found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery.ConclusionOur results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring.     

Brainstem Auditory and Somatosensory Evoked Potentials in Neuro-Behqet's Syndrome

Abstract: Brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials after median nerve stimulation (MN-SEPs) and after posterior tibial nerve stimulation (PTN-SEPs) were studied in 17 patients with neurolehget's syndrome (NB). Eleven patients (64.7%) showed an absence of wave I, III or V or a prolongation of the interpeak latency 1–111, or 111-V in BAEPs. Six patients (37.4%) showed a prolongation in the latency of cortical P37 of PTN-SEPs and/, or the interpeak latency EP-N13 or N13–N18 of MN-SEPs. The BAEP and SEP abnormalities indicated a conduction failure of the acoustic lateral lemniscus pathway and the medial lemniscus pathway in the brainstem of the patients with NB. Abnormal EPs can provide sensitive information which shows the presence of subclinical lesions in the central nervous system.     

脑血管病患者的经颅磁刺激运动诱发电位和短潜伏期体感诱发电位的对比研究

采用经颅磁刺激运动诱发电位（MEP）对72名脑血管病患者进行检测，其中57例还同时测定短潜伏期体感诱发电位（SSEP），并和50例正常人进行对比研究．结果发现脑血管病患者瘫痪侧上肢MEP异常表现为刺激无反应或皮层潜伏期延长和中枢传导时间延长，与正常对照组和健侧比较差异有极高度显著性（P＜0．001），瘫痪侧下肢MEP异常表现为刺激无反应或中枢传导时间延长，与正常对照组和健侧比较，差异有显著性（P＜0．05）．MEP和SSEP异常率在脑出血与脑梗塞之间无显著性差异（P＞0．05），而与临床表现和病变部位密切相关。本文提示MEP和SSEP分别能客观地反映脑血管病愈者中枢运动传导通路和中枢感觉通路功能受损的情况．     

Somatosensory Evoked Potentials in Juvenile Myoclonic Epilepsy

We analyzed the somatosensory evoked potentials (SEP) of 35 patients with juvenile myoclonic epilepsy (JME), 26 patients with idiopathic generalized epilepsy (IGE), and a control group consisting of 24 healthy people. The N19-P25 interval was significantly prolonged in the IGE group both as compared with the JME and control groups. This finding may be related to antiepileptic drug (AED) treatment, principally phenytoin (PHT). No differences were noted in N19 amplitude in any group. The P25 and N33 amplitudes were significantly higher in the JME group. In 5 patients of the JME group (14%) "giant SEP" were observed, but no differences were evident in the electroclinical characteristics with respect to the other JME patients. JME is one of the causes of giant-SEP.     

脑白质疏松症短潜伏期躯体感觉诱发电位研究

对24例经CT证实的脑白质疏松症患者进行短潜伏期躯体感觉诱发电位(SLSEP)顶和中央前成分检测。结果,SLSEP总异常率83.3％,时间参数异常率(79.17％)明显比幅度参数异常率(29.11％)高,中央前成分异常率(75％)明显比顶成分异常率(41.7％)高。结论:在脑白质疏松症的临床早期,体感诱发电位可以敏感反映脑电生理的异常,作为临床诊断该病的辅助手段。     

Predictive Value of Somatosensory Evoked Potential Monitoring during Resection of Intraparenchymal and Intraventricular Tumors Using an Endoscopic Port

Background and Purpose

Intraoperative neurophysiological monitoring (IONM) using upper and lower somatosensory evoked potentials (SSEPs) is an established technique used to predict and prevent neurologic injury during intracranial tumor resections. Endoscopic port surgery (EPS) is a minimally-invasive approach to deep intraparenchymal and intraventricular brain tumors. The authors intended to evaluate the predictive value of SSEP monitoring during resection of intracranial brain tumors using a parallel endoscopic technique.

Methods

A retrospective review was conducted of patients operated on from 2007-2010 utilizing IONM in whom endoscopic ports were used to remove either intraparenchymal or intraventricular tumors. Cases were eligible for review if an endoscopic port was used to resect an intracranial tumor and the electronic chart included all intraoperative monitoring data as well as pre- and post-operative neurologic exams.

Results

139 EPS cases met criteria for inclusion. Eighty five patients (61%) had intraparenchymal and fifty four (39%) had intraventricular tumors or colloid cysts. SSEP changes were seen in eleven cases (7.9%), being irreversible in three (2.2%) and reversible in eight cases (5.8%). Seven patients (5.0%) with intraparenchymal tumors had SSEP changes which met our criterea for significant changes while there were four (2.9%) with intraventricular (p-value=0.25). Five patients suffered post operative deficits, two reversible and two irreversible SSEP changes. Only one case exhibited post operative hemiparesis with no SSEP changes. The positive predictive value of SSEP was 45.4% and the negative predictive value was 99.2%.

Conclusions

Based on the high negative and low positive predictive values, the utility of SSEP monitoring for cylindrical port resections may be limited. However, the use of SSEP monitoring can be helpful in reducing the impact of endoscopic port manipulation when the tumor is closer to the somatosensory pathway.     

橄榄—桥脑—小脑萎缩患者体感诱发电位检测

采用Nicolet－viking－Ⅱ电生理诊断仪对28例橄榄—桥脑—小脑萎缩（OPCA）患者及19例健康志愿者行双侧肢体体感诱发电位（SEP）检查，结果表明：OPCA组正中神经N20潜伏期延长，N20及P23波幅减低，与对照组相比差异有显著性意义（P＜0．05）；中枢传导时间（N13—N20，经协变量校正后）明显延长（P＜0．05），其中N20波缺失1例，均为双侧性；腕部至Erb’s神经传导速度（CVI）及N9、N11、N13潜伏期均正常。左侧N20、右侧P23及胜后神经诱发电位P37潜伏期与对照组相比差异均有显著性意义（P＜0．05），经协变量校正后显示N21、N45潜伏期明显延长（P＜0．05）；而中枢传导时间N21—P37及周围神经的监护电位（PF）均无差异（P＞O．05）；内踝至皮层传导速度（CVZ）减慢，两组相比，差异具有极为显著意义（P＜0．01）；有8例P37波缺失（其中R侧6例，一侧性2例），占28．5％。上述结果提示OPCA患者除了有中枢传导障碍外，可能同时有周围神经传导障碍。     

Somatosensory evoked potentials in a case of neurosyphilis

Here we report median and common peroneal nerve SEPs in a patient with tabes dorsalis. SEPs were within normal limits following median nerve stimulation, but of prolonged latency for common peroneal nerve. This was in keeping with clinical findings of posterior column involvement confined to the lumbosacral tract and with pathological features of tabetic neurosyphilis.

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Sommario Gli autori riportano le caratteristiche dei potenziali evocati somatosensoriali del nervo mediano e peroneo comune in un paziente affetto da tabe dorsale. I potenziali evocati somatosensoriali sono risultati nei limiti della norma stimolando il nervo mediano ma di latenza aumentata per il nervo peroneo comune. Ciò risultava in accordo sia con le caratteristiche cliniche di segni di interessamento dei cordoni posteriori limitato al tratto lombosacrale che con le caratteristiche anatomopatologiche della neurosifilide.

     

Epilepsy in Schizencephaly: Abnormal Cortical Organization Studied by Somatosensory Evoked Potentials

Median nerve short-latency somatosensory evoked potentials (MN-SSEP) are recorded from the scalp to assess parietal lobe function and from the cortex to identify primary sensory and motor areas before epilepsy surgery. Nevertheless, the origins of many of the MN-SSEP waveforms and the reliability of this technique for localizing the central sulcus are not definitively known. We studied a child with a unilateral, closed, right parietal schizencephalic cleft and frequent simple partial seizures before the child underwent cortical resection. The sensory examination, neuroimaging, and electrical brain stimulation findings indicated a normal thalamus and an abnormal parietal lobe. Scalp-recorded MN-SSEPs showed intact widespread N18 potentials bilaterally, but absent right, although normal left parietal N20 and P27 waveforms. Cortically recorded MN-SSEPs could not localize the central sulcus owing to an absence of the expected negative potential over the right postcentral gyrus and the presence of waves with abnormal latencies over the precentral cortex. These findings suggest that: (a) the N18 potential probably originates at or below the level of the thalamus, (b) the N20 and P27 peaks are most likely generated by parietal cortex or white matter, and (c) cortically recorded MN-SSEPs can fail to localize the central sulcus before epilepsy surgery when congenital anomalies exist in the parietal lobe.     

体感诱发电位在重度腕管综合征诊断中的应用

目的探讨临床通过检测正中神经体感诱发电位(SEP)中潜伏期波N60计算重度腕管综合征(CTS)感觉神经传导速度(SNCV)的方法。方法检测对象为15例17腕复合肌肉动作电位(CMAP)未能引出的重度CTS患者和6名健康对照者(作者医院健康查体者),检测点为掌远侧横纹(0点)近端2cm( 2点)及远端2cm(-2点)和4cm(-4点)处3点及中指1点共4点,以患者所能感知最低刺激的3～4倍强度的1.1Hz0.2ms方波分别刺激腕关节和中指所获的SEP峰间差计算SNCV。结果通过N60波峰间差计算所得自掌远侧横纹到中指间的SNCV范围正常对照组为45.1～89.2m/s,平均(67.4±13.0)m/s;在进行中指刺激检测N60波的12腕中,8腕N60波明显延长,SNCV为9.3～21.2m/s,平均(15.6±4.2)m/s(P<0.01),另4腕完全未测出。结论正中神经SEP的N60波可作为对运动和感觉电位均未测出的重度CTS患者进行诊断时判断传导异常的客观指标之一,通过这一方法测得的神经传导速度可供临床参考。     

Evoked potentials

ABSTRACT- A survey is given of my studies of evoked potentials in patients with multiple sclerosis (MS) and in control subjects. Potentials were recorded following random low-rate auditory stimulation (BAEP), checkerboard pattern-reversal stimulation (VEP), somatosensory stimulation (SEP); blink reflexes (BR) were recorded following electrical stimulation of the supraorbital nerve. Normal data had to be related to age and sex in evaluating BAEPs and VEPs.
In 160 MS patients, a total of 421 recordings were obtained. Changes by repeated BAEP and VEP tests might reflect changes in the clinical state, but they also did occur in clinically stable patients. In patients with definite MS, high incidences of abnormality were shown, supporting the clinical findings. The diagnostic value was greatest when clinically silent lesions were demonstrated in patients with suspected or possible MS. In these patients, either BAEP or VEP gave evidence of subclinical lesions in about 50%, and when combined, in 71% of the patients, thus making a transfer to a more certain diagnostic classification possible and invasive examinations unnecessary. When SEP and BR tests were added, subclinical lesions were found in 74% of the patients. The SEP recordings did show a high incidence of abnormality, but only few silent lesions; the BR test was the least sensitive. The VEP was abnormal in all patients with signs of optic neuritis and in all but one with a history of optic neuritis.
The present results are compared to those obtained in other laboratories and with other types of examinations in MS patients. It is concluded that although the tests are not specific for MS, they give valuable information in the majority of patients with a clinically uncertain diagnosis. This information will most often not be given by other types of examination. The combination of VEP and BAEP is recommended, but it should be supplemented by SEP recording in patients without spinal signs.