术中皮层脑电图在颞叶癫痫手术中的应用

目的 探讨术中皮层脑电图(ECoG)在颢叶癫痫手术中的应用价值.方法 回顾性分析105例前颞叶切除手术患者的临床资料与ECoG的监测结果,统计对ECoG的影响因素及其对手术疗效的影响.结果 术前ECoG平均监测时间为72 min,结果显示:无异常11例、颢叶或前颞叶局限性放电73例、广泛痫性放电21例;术后ECoG平均监测时间为38 min,结果显示:无异常91例、颞叶后部痫性放电9例、广泛痫性放电5例.年龄与术前EcoG结果无明显相关性;而病程＜5年者术前EcoG痫性放电局限于前颞叶的比率较高,达到83.3%,且与另外两组差异有统计学意义.有6例(5.7%)根据术后ECoG结果行颞叶皮层后部扩大切除.术前ECoG显示痫性放电局限于前颞叶和术后ECoG正常与其他同期结果间的手术疗效差异有统计学意义,提示术后无癫痫发作.结论 颞叶癫痫患者ECoG监测可发现70%的痫波局限于前颞区,术前和术后ECoG监测结果可用于初步判断手术疗效,ECoG监测对颞叶癫痫手术具有一定的应用价值.     

深部脑电图在七氟醚麻醉条件下的(痫)样放电波幅变异

目的:比较七氟醚在不同麻醉深度下对颞叶癫(痫)手术术中深部电极描记的EEG的影响.方法:颞叶癫(痫)行射频热凝毁损手术患者68例,在七氟醚吸入麻醉,最小肺泡浓度(MAC) =0.6时监测额叶皮质EEG和颞叶深部EEG,再加深麻醉至MAC=1.2时再监测.EEG数据应用快速傅里叶处理(FFT),计算额叶背景平均波幅,测量10个颞叶内侧棘波的波幅,取平均值后确定为该患者的棘波波幅,对MAC=0.6和MAC=1.2两组进行统计.结果:MAC=0.6时颞叶内侧棘波放电波幅平均为(426.2±63.1)μV,额叶10～12 Hz(80.3±16.4)μV背景波幅显著；MAC=1.2时颞叶内侧棘波放电波幅平均为(171.2±32.6)μV,额叶10～12 Hz(550.3±126.8)μV背景波幅显著,两组间的(痫)样放电波幅和额叶背景波幅比较差异均有统计学意义(P＜0.05).MAC≤1.2时,七氟醚吸入麻醉影响背景节律和(痫)样放电的波幅,对频率和波形无明显影响.结论:七氟醚麻醉对深部电极EEG的影响呈剂量依赖性,麻醉过深则可能导致(痫)样放电鉴别困难.     

27例学龄前难治性颞叶癫痫患儿临床报道

目的探讨学龄前难治性颞叶癫痫患儿影像学、电生理特点及手术方法和疗效。方法回顾性分析解放军联勤保障部队第九八八医院神经外科中心自2014年6月至2019年1月行手术治疗的27例学龄前难治性颞叶癫痫患儿资料,术前评估结合临床发作表现,MRI、磁共振波谱分析(MRS)、正电子发射断层扫描(PET-CT)等影像资料,以及发作间期和发作期视频脑电图(VEEG)资料;术中应用皮层脑电图(ECoG)与深部电极监测定位异常放电区域,指导手术切除致痫灶范围。术后采用Engel分级评估疗效。结果27例患儿均有典型颞叶癫痫临床表现,MRI发现一侧颞叶及海马异常信号影,发作间期及发作期VEEG提示异常放电起始于一侧额颞部。术中ECoG及深部电极监测均发现颞叶明显持续或阵发性尖波、棘波、棘慢复合波等癫痫样放电。27例患儿均采用标准前颞叶+病灶切除+周边异常放电颞叶皮质扩大切除术,其中2例患儿切除部分岛叶长回及额盖皮质热灼处理。随访6个月,EngelⅠ级患儿22例,EngelⅡ级患儿3例,EngelⅢ级患儿2例。结论早期手术、术中ECoG与深部电极联合监测下适度扩大切除范围是改善学龄前难治性颞叶癫痫患儿手术疗效的关键因素。     

皮质脑电图联合深部电极监测在症状性癫痫手术中的应用及疗效影响因素分析

目的 探讨皮质脑电图(ECoG)联合深部电极监测在症状性癫痫手术中的应用及疗效影响因素分析.方法 回顾性分析2017年1月-2020年6月该院收治的24例行症状性癫痫手术患者的临床资料.术中采用ECoG联合深部电极监测并定位致痫灶,确定手术切除病灶深度、范围及周围致痫灶.术后随访12个月,采用Engel分级评估疗效,并根据疗效分为有效组(18例)、无效组(6例).采用单因素分析、多因素Logistic回归分析症状性癫痫手术疗效的影响因素.结果 所有患者均顺利完成手术,术中ECoG、深部电极均监测到病变处阵发性或持续性棘慢复合波、棘波、尖波;此外,深部电极还在病变周围正常脑组织内监测到明显棘慢复合波、尖波,但放电程度及频率均较病变部位低.术后出现暂时性单侧肢体轻度偏瘫、语言障碍、情感淡漠各2例,术后2个月恢复正常,术后无严重感染及颅内出血等发生.多因素Logistic回归分析结果显示,病程＞2年[OR:6.500,95％CI:1.741～24.274]、部分切除致痫灶[ORe:14.583,95％CI:1.545～137.661]为症状性癫痫手术疗效的危险因素,而术后无早期发作[OR:0.066,95％CI:0.012～0.368]为症状性癫痫手术疗效的保护因素.结论 症状性癫痫手术中采用ECoG联合深部电极监测可精准定位致痫灶深度及范围.患者病程、致痫灶切除程度、术后早期癫痫发作情况等为症状性癫痫手术疗效影响因素.     

皮质脑电图在脑海绵状血管瘤所致癫痫手术中的应用研究

目的 研究皮质脑电图(ECoG)在脑海绵状血管瘤(BCA)所致癫痫手术中的作用.方法 对经正规抗癫痫治疗无效的85例BCA致癫痫患者,在ECoG监测下进行致痫灶定位,指导手术治疗.术后对患者进行随访及疗效评定.结果 术中ECoG监测发现本组患者的BCA病变区均存在棘波发放,而术前头皮EEG仅56例存在棘波,术中ECoG还发现31例患者有新的致痫灶.所有患者在ECoG监测下进行致痫灶切除(非功能区)或低功率热灼术(功能区).术后平均随访3.4年,疗效满意(癫痫发作完全消失)61例(71.8％),良好(发作减少≥50％)18例(21.2％),差(发作减少＜50％)6例(7.1％);总有效(满意+良好)率92.9％.结论 ECoG监测可在BCA所致癫痫手术中准确定位致痫灶,明显提高手术的疗效.     

皮层脑电图辅助立体定向下手术治疗颅内钙化灶引起的难治性癫痫

目的研究立体定向下开放式手术联合术中皮层脑电图(ECoG)监测治疗颅内钙化灶性癫痫的手术方法、注意事项及效果。方法 21例颅内单发钙化灶引起的癫痫患者(其中主要功能区钙化灶9例),在立体定向仪导向下,开放直视手术,ECoG监测钙化灶周围皮层脑电活动情况,切除钙化灶后再次ECoG监测,确定致痫灶的范围及处理方式。结果所有钙化灶均被顺利切除。钙化灶区域ECoG监测无明显异常5例,表现为阵发性与动脉搏动相一致的单发性棘慢复合波发放9例,表现为明显癫痫样放电7例。单纯钙化灶切除术14例,钙化灶+周边增生组织+致痫皮层切除术4例,钙化灶切除+功能区致痫皮层低功率电凝热灼术3例。术后ECoG监测发现异常放电消失11例,仍残存轻中度痫样放电5例。无严重并发症。随访6个月～8年,EngelⅠ级16例,EngelⅡ级5例,总有效率100%。结论 ECoG监测是立体定向下手术治疗颅内钙化灶性癫痫的重要辅助手段,能够指导术中采取相应的手术方式切除钙化灶,妥善处理致痫灶,避免过多损伤脑皮层。     

多处软膜下横切术联合其它术式治疗顽固性癫痫

目的探讨多处软膜下横纤维切断术(MST)联合病灶或/和致痫脑叶切除对顽固性癫痫的治疗.方法术前将经临床、电生理、神经影像学及核医学检查结果进行综合分析、定位.取大骨瓣开颅,术中行皮层脑电(ECoG)监测.首先切除脑的结构性病灶;对颞叶癫痫,行较小范围的前颞叶切除,并切除颞叶内侧结构;对痫灶位于额极底面者,行额极切除.复查ECoG,对残余的痫样放电区域,不论是否位于重要功能区,均行MST直至术野内痫样波基本消失.结果本组51例无手术死亡和明显并发症.随访1～7年,有效率(发作频率减少50%以上)为90.2%,显效率(发作频率减少75%以上)为80.4%,效差或无效9.8%.术后复查脑电图多有明显改善.结论在顽固性癫痫的治疗中,将MST联合病灶或/和致痫脑叶切除,既能取得较好的疗效又能保留更多的脑组织.     

功能区皮层下小病灶相关性癫痫的手术治疗

目的评价综合应用多种定位技术治疗功能区皮层下小病灶相关性癫痫的手术方法及效果。方法 58例功能区皮层下小病灶引起的癫痫患者,在立体定向仪导向下,开放直视手术切除病灶,术中皮层脑电图(ECoG)监测定位致痫灶,术中神经电生理监测(IOM)判断致痫区的功能以及二者的重叠程度,辅助以麻醉唤醒定位语言区、实时超声检查病变切除程度,根据监测结果分别采取致痫灶切除术、多处软膜下横切术(MST)或皮层低功率电凝热灼术妥善处理致痫灶。结果病灶全部切除52例,少量残留6例。病灶区域ECoG监测除波幅略有降低外无明显异常13例,行占位病灶切除术;ECoG明显异常,在非主要功能区8例,行占位病灶+周边致痫皮层切除术;ECoG明显异常而又在主要功能区37例,行占位病灶+功能区致痫皮层多处软膜下横切术(MST)或低功率电凝热灼术。ECoG监测发现痫样放电消失、基本节律大致恢复正常29例,仍残留少量棘波13例,残存较多棘波且基本节律轻到中度异常16例。随访1～5年,EngelⅠ级46例,EngelⅡ级8例,EngelⅢ级4例,总有效率100%。出现暂时性轻偏瘫17例,暂时性失语8例,无严重永久性并发症。结论综合应用立体定向引导、术中IOM、ECoG、麻醉唤醒及实时超声定位治疗功能区小病灶相关性癫痫,能够精准定位并切除病灶及处理致痫灶,避免损伤功能区,是一种微创、安全、有效的手术方法。     

伴有癫痫发作的脑内病灶的手术治疗

目的 研究伴有癫痫发作的脑内病灶的手术治疗效果。方法 本组24例病人中，EEG示13例有局部痫样波，5例局灶慢波，6例正常。在皮质脑电图(ECoG)监测下手术．11例痫灶位于病灶表面或紧邻其边缘，行病灶 痫灶切除；8例痫灶距病灶10mm以上，其中6例位于非功能区，行病灶 痫灶切除；2例位于功能区，行病灶切除及热凝痫灶皮质；2例痫灶位于前颞叶深部，行前颞叶及病灶切除。3例ECoG正常，仅行病灶切除。结果 21例痫灶切除病人中，15例(71％)术后癫痫完全消失，2例(10％)发作显减少，4例(19％)发作减少。结论 对伴有癫痫发作的脑内病灶病人，术中ECoG及深部电极有助于精确定位痫灶；切除病灶、痫灶，效果良好。     

立体定向联合术中皮层电极、神经电生理监测治疗功能区皮层下小肿瘤性癫痫

目的 评价采用立体定向联合术中皮层脑电图(ECoG)、神经电生理监测(IOM)治疗功能区皮层下小肿瘤性癫痫的手术方法及效果、并发症. 方法 解放军第153医院神经外科自2006年6月至2011年6月共收治功能区皮层下小肿瘤引起的癫痫患者15例,均在立体定向仪导向下,开放直视手术准确切除肿瘤,ECoG监测定位致痫灶,IOM判断致痫灶与功能区的重叠程度,分别采取切除术、多处软膜下横切术(MST)或皮层低功率电凝热灼术处理致痫灶.总结分析患者的手术方法及疗效. 结果 本组肿瘤全切13例,次全切2例;瘤周致痫灶切除4例,瘤周致痫灶MST或/和皮层低功率电凝热灼术11例;术毕ECoG监测发现痫样放电消失、基本节律大致恢复正常6例,仍残留少量棘波6例,残存较多棘波且基本节律轻到中度异常3例;无严重永久性并发症;随访1～3年,肿瘤原位复发2例,Engel分级Ⅰ级10例,Ⅱ级3例,Ⅲ级2例,总有效率100％.结论 立体定向联合术中ECoG、IOM治疗功能区皮层下小肿瘤性癫痫,能够精准定位并切除肿瘤及处理致痫灶,避免损伤功能区,是一种微创、安全、有效的手术方法.     

The Effects of Remifentanil on Epileptiform Discharges during Intraoperative Electrocorticography in Patients Undergoing Epilepsy Surgery

PURPOSE: High-dose i.v. opioids (e.g., alfentanil, 50 microg/kg bolus) are known to increase the intraoperative reading of epileptiform activity during epilepsy surgery (ES), thereby facilitating localization of the epileptogenic zone (i.e., the site of ictal onset and initial seizure propagation). However, this phenomenon has not been studied with remifentanil (i.e., a novel ultra-short acting opioid). The purpose of the present study was to evaluate the effect of remifentanil on electrocorticography (ECoG) during ES. METHODS: After Institutional Review Board approval, 25 adult patients undergoing elective ECoG-guided anterior temporal corticectomy were enrolled. At the time of ECoG, anesthesia consisted of inhaled isoflurane < or =0.1% (end-tidal) in 50% N2O, and i.v. fentanyl, 2 microg/kg/h and vecuronium. Patients were maintained at normocapnia and normoxia during ECoG. After acquisition of baseline ECoG, bolus remifentanil, 2.5 microg/kg i.v., was administered. The number of epileptiform spikes occurring 5 min before and after this bolus were compared by using a one-sided sign test; p values < or =0.05 were considered statistically significant. RESULTS: When compared with baseline ECoG, bolus i.v. remifentanil significantly increased the frequency of single spikes or repetitive spike bursts in the epileptogenic zone while suppressing activity in surrounding normal brain. CONCLUSIONS: During ES, remifentanil enhanced epileptiform activity during intraoperative ECoG. Such observations facilitate localization of the epileptogenic zone while minimizing resection of nonepileptogenic eloquent brain tissue. Although not specifically evaluated in this study, we speculate that remifentanil's short elimination half-life will facilitate neurologic function testing immediately after ES. Should this be the case, we envision remifentanil has the potential to supplant other opioids (e.g., alfentanil) during ECoG-guided ES.     

Magnetoencephalography is more successful for screening and localizing frontal lobe epilepsy than electroencephalography

PURPOSE: The diagnosis of frontal lobe epilepsy may be compounded by poor electroclinical localization, due to distributed or rapidly propagating epileptiform activity. This study aimed at developing optimal procedures for localizing interictal epileptiform discharges (IEDs) of patients with localization related epilepsy in the frontal lobe. To this end the localization results obtained for magnetoencephalography (MEG) and electroencephalography (EEG) were compared systematically using automated analysis procedures. METHODS: Simultaneous recording of interictal EEG and MEG was successful for 18 out of the 24 patients studied. Visual inspection of these recordings revealed IEDs with varying morphology and topography. Cluster analysis was used to classify these discharges on the basis of their spatial distribution followed by equivalent dipole analysis of the cluster averages. The locations of the equivalent dipoles were compared with the location of the epileptogenic lesions of the patient or, if these were not visible at MRI with the location of the interictal onset zones identified by subdural electroencephalography. RESULTS: Generally IEDs were more abundantly in MEG than in the EEG recordings. Furthermore, the duration of the MEG spikes, measured from the onset till the spike maximum, was in most patients shorter than the EEG spikes. In most patients, distinct spike subpopulations were found with clearly different topographical field maps. Cluster analysis of MEG spikes followed by dipole localization was successful (n = 14) for twice as many patients as for EEG source analysis (n = 7), indicating that the localizability of interictal MEG is much better than of interictal EEG. CONCLUSIONS: The automated procedures developed in this study provide a fast screening method for identifying the distinct categories of spikes and the brain areas responsible for these spikes. The results show that MEG spike yield and localization is superior compared with EEG. This finding is of importance for the diagnosis and preoperative evaluation of patients with frontal lobe epilepsy.     

EEG source imaging: correlating source locations and extents with electrocorticography and surgical resections in epilepsy patients.

SUMMARY: It is desirable to estimate epileptogenic zones with both location and extent information from noninvasive EEG. In the present study, the authors use a subspace source localization method (FINE), combined with a local thresholding technique, to achieve such tasks. The performance of this method was evaluated in interictal spikes from three pediatric patients with medically intractable partial epilepsy. The thresholded subspace correlation, which is obtained from FINE scanning, is a favorable marker, which implies the extents of current sources associated with epileptic activities. The findings were validated by comparing the results with invasive electrocorticographic (ECoG) recordings of interictal spike activity. The surgical resections in these three patients correlated well with the epileptogenic zones identified from both EEG sources and ECoG potential distributions. The value of the proposed noninvasive technique for estimating epileptiform activity was supported by satisfactory surgery outcomes.     

Spatiotemporal relationship between seizure activity and interictal spikes in temporal lobe epilepsy.

PURPOSE: To analyze the spatio-temporal relationship between seizure propagation and interictal epileptiform discharges (IEDs) in patients with bitemporal epilepsy. METHODS: We investigated 18 adult patients with intractable temporal lobe epilepsy (TLE) who had undergone continuous video-EEG monitoring during presurgical evaluation. Only those patients were selected who had independent IEDs over both temporal lobes. Two authors evaluated the ictal and interictal EEG data independently. RESULTS: We analyzed 52 lateralized seizures of 18 patients. Thirty-one seizures showed ipsilateral seizure spread exclusively, whereas in 21 seizures the contralateral hemisphere was also involved. In lateralized seizures without contralateral propagation, we found that spikes ipsilateral to the seizure onset occurred postictally in a greater ratio than preictally (P<0.001). In lateralized seizures with contralateral propagation, we found no significant changes in the postictal spike distribution. CONCLUSIONS: Our findings showed that the lateralization of IEDs may depend on the brain areas involved by the preceding seizures, suggesting that spikes can be influenced by the seizure activity, and are not independent signs of epileptogenicity.     

皮层脑电监测下颞叶病变合并癫的手术治疗

目的探讨皮层脑电监测下合并颞叶病变的癫手术治疗效果。方法 21例伴有癫症状的颞叶病变患者,术中通过皮层脑电图确定癫灶,切除病变后,切除或热灼可疑癫疒间灶。术后随访患者的癫发作情况。结果 21例患者切除颞叶病变前均可通过皮层脑电图探及疒间波,病变及疒间灶完全切除后,癫波消失者19例,2例功能区患者虽多次皮层热灼,仍可见偶发棘波。术后20例未再有癫疒间发作,1例有部分性发作,用抗癫疒间药可控制。结论术中皮层脑电监测切除或热灼癫灶是一种有效控制颞叶病变切除术后癫发作的方法。     

Misleading non-epileptic epileptiform activities on intracranial recordings

Numerous non-epileptic physiological electroencephalographic (EEG) patterns morphologically mimic epileptiform activity. However, misleading non-epileptic findings of electrocorticography (ECoG) have not yet been examined in detail. The aim of the present study was to identify non-epileptic epileptiform ECoG findings. We retrospectively reviewed the intracranial recordings of 21 patients with intractable focal epilepsy who became seizure-free after a presurgical evaluation with subdural electrodes following resective surgeries at Sapporo Medical University between January 2014 and December 2018. Morphological epileptiform findings outside epileptogenic areas were judged as non-epileptic and analyzed. Seventeen areas in nine patients exhibited non-epileptic epileptiform activities. These areas were identified in the lateral temporal cortices, basal temporal areas, rolandic areas, and frontal lobe. Morphological patterns were classified into three types: 1) spiky oscillations, 2) isolated spiky activity, and 3) isolated fast activity. The normal cortex may exhibit non-epileptic epileptiform activities. These activities need to be carefully differentiated from real epileptic abnormalities to prevent the mislocalization of epileptogenic areas.     

Neurons in human epileptic cortex: Correlation between unit and EEG activity

A total of 90 neurons were recorded extracellularly from 17 awake patients undergoing craniotomy for excision of epileptogenic cortex. Relationships between single-unit activity and gross epileptiform spikes recorded locally by the microelectrode or from the immediate overlying cortical surface by electrocorticography (ECoG) were examined. Similar relationships were also sought between interictal bursts from nearby cells when action potentials from several neurons had been recorded simultaneously by the tungsten electrodes. Although 40 single units fired action potentials in some relation to ECoG spikes, the relationships were variable between units and, often, for the same unit. For many units, action potentials were more consistently related to one phase of the local field potential recorded through tungsten microelectrodes than to the ECoG recorded from the overlying cortical surface. Synchronous firing between single units recorded simultaneously by the same microelectrode was rarely seen except at the onset of an ictal event. In addition, a high degree of synchrony between unit firing and local ECoG spikes was recorded in a few patients, but these patients had frequent focal spontaneous seizures. The data imply that in human epilepsy, unlike some animal models of the disorder, relationships between surface epileptiform events and single-unit burst firing are not easily found in interictal recordings. The data also suggest that synchrony between unit and surface events requires a high degree of synchrony among neurons within the epileptogenic focus.     

Effect of Isoflurane (Forane) on Intraoperative Electrocorticogram

Isoflurane, an inhalation agent often used for general anesthesia during craniotomy, has been reported to suppress spike activity in the intraoperative electrocor-ticogram (ECoG) during epilepsy surgery. We studied the effect of isoflurane concentrations of 0.25, 0.5, 0.75, 1, and 1.25% on the number of spike bursts per 5-min epochs in 15 patients undergoing ECoG during epilepsy surgery. N₂O in O₂ was maintained at 50% in 10 patients, at 60% in 2, and at 70% in 3. End tidal CO₂ concentration was maintained in the hypocarbic range, and analgesia was maintained with the narcotic alfentanil in the range of 0.5–2 μg/kg/min. The median number of spikes for each isoflurane concentration was 29 (range 3–107) at 0.25%, 27 (range 2–73) at 0.5%; 29 (range 5–90) at 0.75%, 33 (range 2–100) at 1%, and 40 (range 32–140) in 5 patients who tolerated 1.25% without occurrence of burst suppression pattern. No significant difference (Student's paired t test) was noted in the number of spikes for each isoflurane concentration. Therefore, if isoflurane concentrations are maintained between 0.25 and 1.25% or before burst suppression pattern occurs and N₂O/O₂ is maintained in the 50–70% range, isoflurane has no significant effect on spike activity.