颅内电极监测技术在癫痫手术中的应用

目的探讨颅内电极监测技术在难治性癫痫外科治疗中的应用价值。方法对头皮脑电图及影像学等非侵袭性检查难以确定致痫灶或致痫灶与重要功能区关系密切的51例难治性癫痫患者,行颅内电极埋置术,长程视频脑电图监测确定致痫灶,并行脑皮层电刺激功能区测定,再次手术切除致痫灶。结果术后致痫灶切除效果按Engel分级：I级32例,Ⅱ级13例,Ⅲ级5例,Ⅳ级1例。术后发生头皮愈合不良3例,延长住院时间后治愈。无脑脊液漏及永久性神经功能缺失发生。结论颅内电极监测可以精确定位致痫灶,皮层电刺激术对脑功能区定位可靠、方便,故对于采用非侵袭性检查不能明确致痫灶或致痫灶与重要功能区关系密切的难治性癫痫患者,颅内电极监测结合皮层电刺激术可以提高其治愈率,并有效降低并发症发生率。     

颅内电极监测结合神经导航治疗功能区难治性癫痫24例临床分析

目的探讨颅内电极监测结合神经导航技术在难治性癫痫手术中的疗效。方法对24例难治性癫痫患者行颅内电极置入长程脑电图监测(intracranial EEG,iEEG)进行致痫区定位,二次手术前行磁共振扫描,数据输入神经导航系统,手术当天进行导航注册配准,神经导航引导手术入路,术中结合颅内电极描记切除癫痫灶,尽可能减少功能区损伤。结果手术后致痫灶切除效果:EngelⅠ级19例,Ⅱ级4例,Ⅲ级1例。无术后神经功能障碍。结论颅内电极监测结合神经导航的应用可使难治性癫痫外科手术更精确,侵袭更小。     

颅内电极脑电监测定位致痫灶

目的 探讨颅内埋置电极脑电图(iEEG)监测定位致痫灶的意义及其安全性。方法 对38例经无创方法难以定位的难治性癫痫病人，采用颅骨钻孔或骨瓣开颅方法埋置硬膜下和(或)深部电极，行长程视频脑电监测定位致痫灶。根据术中致痫灶定位、术后病理、术后疗效和EEG复查结果分析iEEG监测定位致痫灶的准确性。结果8例埋置深部电极，13例埋置硬膜下电极，17例联合应用硬膜下电极和深部电极。颅内电极埋置4～22d，平均9d；脑电监测8～226h，平均128h．根据癫痫发作初始期iEEG，32例(84．2％)病人准确定位了致痫灶，无颅内出血和感染等严重并发症发生。结论选择性应用硬膜下和深部电极长程视频脑电监测是一种安全、有效的检查方法；癫痫发作初始期异常放电的节律和范围是可靠的致痫灶定位指标．     

脑深部电极监测在致痫灶定位中的应用

目的评估脑深部电极置入后对定位致痫灶及指导手术治疗的可靠性和安全性。方法对108例药物难治性癫病人行脑深部电极置入,其中采用立体定向电极置入77例,神经导航电极置入11例,术区徒手置入20例。根据头皮脑电图监测情况和脑深部电极提供的手术路径,行致灶切除。结果根据监测情况,头皮脑电图不能定位而通过深部电极定位98例,两者定位于不同区域7例,两者均不能定位3例。术后病理：局灶性皮质发育不良38例,颞叶内侧硬化42例,结节性硬化11例,神经节细胞胶质瘤7例,胶质增生9例,错构瘤1例。术后随访91例,时间6～36个月,Engle分级：Ⅰ级66例,Ⅱ级25例;复查脑电图,痫样异常放电消失或明显改善。术后并发脑出血5例,硬膜外血肿6例,蛛网膜下腔出血3例,电极因发作脱出或拔出1例,剧烈头痛3例,无死亡病例。结论初期评估不能明确定位的脑深部致痫灶,通过脑深部电极定位是安全、可靠的。     

6例磁共振阴性额叶癫痫患者致痫灶定位研究

目的探讨硬膜下电极脑电图(ECo G)监测对磁共振阴性癫痫患者致痫灶的定位作用。方法对经临床、影像学和头皮EEG检查不能确定致痫灶部位的6例难治性额叶癫痫患者,植入硬膜下条状电极进行视频EEG监测,观察颅内电极发作期及发作间期EEG变化,结合头皮EEG、临床发作结果对癫痫灶进行综合定位;术后随访,评估致痫灶定位的准确性。结果 6例患者颅内电极埋藏时间为2~5 d,每例监测到2次临床发作并记录发作间期和发作期的异常放电活动。5例患者发作期颅内电极EEG均能准确定位,5例显示一侧局灶性放电起源,1例患者显示双侧放电起源。术后按Engel疗效分级:EngelⅠ级4例(57.1%),EngelⅡ级1例(14.3%),随访不满1年的按谭氏术后效果分级,达到了满意。结论颅内电极EEG监测可为癫痫手术治疗提供可靠的病灶定位依据。     

颅内电极脑电图监测在癫癎外科的应用(附29例分析)

目的 探讨颅内电极置入术在临床的应用时机、方法，评估颅内电极脑电图（i-EEG）技术在癫痫外科中的价值。方法回顾性分析29例难治性癫痫病例．在参考非侵入性评估结果的基础上．采用颅内电极置入、长程脑电图监测技术进行可能的致痫区定位。结合术后癫痫控制情况和随访记录．综合分析i-EEG在术前评估中的作用。结果联合置入深部电极和硬膜下条状皮质电极14例，其中深部电极置入双侧海马10例，双侧海马-杏仁核4例：单纯置入硬膜下条状皮质电极4例：置入硬膜下条状和栅状皮质电极7例；置入硬膜外条状和栅状电极4例。电极留置颅内3～14d，平均5．5d；监测时间24～160h，平均38h；捕捉到临床发作5～58次，平均7．8次。置入电极后，17例（58．6％）出现暂时性脑脊液外漏．3例出现颅内少量血肿，1例出现深部电极折断。无感染和死亡病例。手术27例．随访4～30个月：Engel Ⅰ级19例．Ⅱ级4例，Ⅲ级4例。结论对难治性癫痫而言，当非侵入性评估结果难以确定可能的致痫区时．采用颅内电极置入并进行长程脑电图监测是定位可能致痫区一种有效、安全的方法。     

影像导航下立体定向脑电监测在额叶癫痫中的应用…

目的 探讨影像导航引导下颅内立体脑电图监测在额叶癫痫外科治疗中的作用。方法 选取2014年1月至2016年3月35例定位定侧困难的额叶癫痫,采用美敦力S7导航系统融合MRI影像,根据脑网络在导航下置入电极,术后监测脑电图定位癫痫病灶,手术切除致痫灶。结果 35例均按计划成功置入深部电极,其中单侧12例,双侧23例,均监测到3~20次临床惯常发作。1例定位困难,未手术治疗;其余34例根据脑电图结果行致痫灶切除。置入电极后1例发生硬膜外血肿,量约20 ml,癫痫病灶切除时一并清除;癫痫病灶切除术后1例早期出现单瘫,1例出现运动性失语,经治疗后恢复。34例手术病人术后随访1~3年,Engel分级Ⅰ级24例（70.5%）,Ⅱ级5例（14.7%）,Ⅲ级4例（11.7%）,Ⅳ级1例（2.9%）。结论 影像导航下立体定向脑电图定位癫痫病灶在额叶癫痫的外科治疗是安全、有效的。     

长程颅内电极记录定位致痫灶的效果分析

目的 讨论应用颅内埋藏电极进行长程视频脑电(Video-EEG)监测，对于致痫灶的定位作用。方法 应用立体定向技术，向颅内可疑部位植入深部电极和／或硬膜下条状电极。采用DaVinci系统，进行长程视频脑电监测，记录发作间期及发作期EEG变化，确定癫痫起源部位。在皮层电极脑电图(ECoG)监测下，手术切除致痫灶或行立体定向毁损术。结果 本组17例患者颅内电极埋藏时间4～17天，平均9天。各例均记录到明确的发作间期异常放电和／或发作期EEG变化。手术切除致痫灶16例(联合胼胝体切开术1例)；行双侧杏仁核毁损术1例。术后复查Vidoo-EEG，显示痫性放电基本消失15例，改善2例(集中于手术对侧1例)。按照Engel术后效果分级：Ⅰ级15例，Ⅲ级1例，Ⅳ级1例。所有病例均未出现因长时间埋藏颅内电极引起的并发症。结论 在致痫灶定位困难的难治性癫痫患者中，应用埋藏式颅内深部电极和／或硬膜下条状电极，进行长程颅内电极记录，可以精确定位致痫灶，可改变外科治疗计划，从而提高了癫痫的治愈率及手术成功率。     

颅内电极埋藏在Lennox-Gastaut综合症中的应用(附10例临床分析)

目的探讨颅内电极埋藏术后进行视频脑电图评估在癫痫外科手术致痫灶定位困难的Lennox-Gastaut综合症中的使用。方法收集10例Lennox-Gastaut综合症致痫灶定位困难的患者,向颅内硬膜下植入条状电极,术后进行视频脑电图评估,记录发作间歇期及发作期脑电图变化,确定癫痫病灶的起始区,通过手术方式切除致痫灶。结果本组10例患者埋藏时间为2～7天,平均4天,均记录到间歇期及发作期脑电图情况。根据脑电图结果,行脑叶切除及胼胝体切开。术后按照Engel评分I级4例,II级2例,III级2例,IV级2例。所有病例均未出现埋藏电极引起的严重并发症。结论在致痫灶定位困难的Lennox-Gastaut综合症中,采用颅内电极埋藏进行视频脑电图检测,可以较准确定位主要致痫灶,从而提高Lennox-Gastaut综合症外科治疗有效率。     

颅内电极埋藏在枕叶癫痫中的作用

目的探讨运用颅内电极埋藏进行视频脑电图监测在定位困难的枕叶癫痫中的作用。方法通过对9例枕叶癫痫但定侧定位困难的患者,向颅内可疑部位植入硬膜下条状电极,进行视频脑电图监测,记录发作间期及发作期脑电图变化,确定癫痫病灶起始区。通过手术切除致痫灶。结果本组9例埋藏时间为3～9d,平均5d,均记录到间歇期痫样放电及发作期脑电图情况。行枕叶局部皮层切除6例及枕叶切除3例。术后按照Engel评分,I级7例,II级2例。所有病例均未出现埋藏电极引起的并发症。结论在致痫灶定位困难的顽固性枕叶癫痫中,采用颅内电极埋藏进行脑电图监测,可以精确定位致痫灶,从而提高癫痫的治愈率。     

Periictal SPECT localization verified by simultaneous intracranial EEG

PURPOSE: We investigated whether blood-flow changes measured by ictal or immediate postictal single photon emission computed tomography (SPECT) reflect with accuracy the actual location of ictal discharge as measured by simultaneous intracranial EEG. In addition, we evaluated the reliability of ictal SPECT obtained with implanted electrodes by comparing results with those of ictal SPECT performed during scalp EEG monitoring in selected patients. METHODS: Eleven patients with intractable partial epilepsy who had both ictal and interictal SPECT scans during invasive EEG monitoring were studied. We analyzed perfusion differences based on registration, normalization, and subtraction of periictal and interictal SPECT images. SPECT results were interpreted in relation to location and evolution of ictal EEG change, as reflected by simultaneous intracranial EEG. In five patients, we also compared ictal SPECT results that were obtained during both scalp and intracranial EEG monitoring. RESULTS: In 10 of 11 patients, localized increases or decreases in blood flow or both were identified in regions of ongoing or prior seizure discharge, respectively, at the time of SPECT brain perfusion. In one patient, SPECT localization could not be verified by the available electrode array. CONCLUSIONS: Localization of ictal discharge during or before SPECT injection accurately determines increase or decrease in perfusion, respectively, and both are of equal validity in reflecting the region of epileptic discharge. SPECT perfusion changes can be reliably obtained during intracranial monitoring.     

Intracranial EEG substrates of scalp EEG interictal spikes

PURPOSE: To determine the area of cortical generators of scalp EEG interictal spikes, such as those in the temporal lobe epilepsy. METHODS: We recorded simultaneously 26 channels of scalp EEG with subtemporal supplementary electrodes and 46 to 98 channels of intracranial EEG in 16 surgery candidates with temporal lobe epilepsy. Cerebral discharges with and without scalp EEG correlates were identified, and the area of cortical sources was estimated from the number of electrode contacts demonstrating concurrent depolarization. RESULTS: We reviewed approximately 600 interictal spikes recorded with intracranial EEG. Only a very few of these cortical spikes were associated with scalp recognizable potentials; 90% of cortical spikes with a source area of >10 cm(2) produced scalp EEG spikes, whereas only 10% of cortical spikes having <10 cm(2) of source area produced scalp potentials. Intracranial spikes with <6 cm(2) of area were never associated with scalp EEG spikes. CONCLUSIONS: Cerebral sources of scalp EEG spikes are larger than commonly thought. Synchronous or at least temporally overlapping activation of 10-20 cm(2) of gyral cortex is common. The attenuating property of the skull may actually serve a useful role in filtering out all but the most significant interictal discharges that can recruit substantial surrounding cortex.     

Local brain activity persists during apparently generalized postictal EEG suppression

ObjectivesPostictal generalized EEG suppression (PGES) frequently occurs after generalized convulsive seizures (GCS) and may be involved in the pathophysiology of sudden unexpected death in epilepsy (SUDEP). It is usually determined using conventional scalp EEG which is likely to miss cerebral activity in deeper brain structures. Here, we examined intracranial EEG activity after GCS to unravel the pattern and extent of local brain activity during apparent PGES on scalp EEG (s-PGES).MethodsWe retrospectively reviewed electroencephalographic data of people with chronic epilepsy who had GCS during presurgical video-EEG monitoring using simultaneous intracranial and scalp EEG (10–20 system) electrodes.ResultsTwenty-five GCS (20 with s-PGES) of 15 patients with an average number of 88 ± 42 intracranial electrode contacts were included. The majority of GCS with s-PGES (18 of 20) displayed persisting or reemerging intracranial EEG activity during apparent PGES on scalp EEG. Three patterns were identified: Pattern 1 (11 GCS, 6 patients) consisted of continuous local interictal activity; Pattern 2 (5 GCS, 5 patients) displayed suppressed EEG activity at all intracranial contacts in the early phase of s-PGES, but reemerging local brain activity before s-PGES dissolved; and Pattern 3 (2 GCS, 2 patients) showed persistent local ictal activity during s-PGES. Persisting intracranial EEG activity at PGES onset on scalp EEG was present in 10 ± 14% (range: 0 to 42%) of all intracranial contacts and mostly in the temporal lobe.ConclusionsOur results reveal that, during apparently generalized postictal EEG suppression, local brain activity persists or reemerges in most GCS. Possible implications of this localized neuronal activity in the context of SUDEP are discussed in the paper.     

颅内电极监测对顽固性颞叶癫痫致痫灶的定位价值

目的:探讨发作期及发作间期颅内电极监测对癫痫灶的定位作用。方法:20例难治性颞叶癫痫,经临床、影像学及头皮脑电图不能确定致痫灶部位,应用立体定向技术,在患者双侧颞叶植入硬膜下条状电极,进行长时间视频脑电图监测,记录发作期和发作间期的脑电图变化,并与头皮脑电图、MRI进行比较,分析癫痫灶部位,进行手术治疗,术后跟踪随访,评估致痫灶定位的准确性。结果:20例癫痫病人颅内电极埋藏时间1～5天,每个患者至少监测到2次临床发作,每一病例均记录发作间期和发作期的异常放电活动。15例发作间期与发作期定侧一致,2例发作间期为双侧棘波病灶,3例发作间期定位与发作期不一致。按Engel术后效果分级:手术效果满意(癫痫发作消失)13例(65%),显著改善3例(15%),良好3例(15%),无效1例(5%)。所有病例均未出现因颅内电极埋藏而致的并发症。结论:对于致痫灶不能定位的难治性癫痫,应用颅内电极记录方法,尤其是发作期起始时脑电图变化,可以确定致痫灶位置,为癫痫手术治疗提供可靠的依据。     

Iatrogenic seizures during intracranial EEG monitoring

Cerebral edema with declining neurologic status is a known complication of intracranial electroencephalography (EEG) monitoring. The frequency and consequences of iatrogenic edema that is not clinically evident are presently poorly defined. We investigated the potential for intracranial electrodes to cause subclinical cerebral edema, and for such edema to cause iatrogenic seizures. In a retrospective review of 33 adults who had head magnetic resonance imaging (MRI) while undergoing epilepsy surgery evaluation with intracranial EEG, 28% (6 of 21) depth electrode implantations had subclinical vasogenic edema. Of these, 50% (3 of 6) had nonhabitual electrographic seizures that appear to result from iatrogenic edema. No long-term adverse sequelae were noted, however, if unrecognized, iatrogenic seizures could lead to unnecessary exclusion from definitive surgical intervention for refractory epilepsy.     

惊吓性癫痫的临床、脑电图特征及手术治疗

目的 探讨惊吓性癫痫的临床、脑电图(EEG)特征及手术治疗效果.方法 回顾性分析经抗癫痫药物或手术治疗的9例惊吓性癫痫的临床资料,总结发作症状学,头皮EEG,颅内EEG及头颅MRI特点,随访手术治疗效果.结果 所有患者的多数发作均由惊吓诱发,仅2例存在少量自发发作.8例MRI发现结构性病变,头皮EEG显示多灶性或局灶性癫痫样放电.2例行颅内电极监测,对致痫灶进行了较精确的定位.5例手术治疗,3例大脑半球切除术,2例局部癫痫灶切除.术后随访6-30个月(平均18.6个月),Engel Ⅰ级4例,Engel Ⅲ例1结论多数惊吓性癫痫患者存在脑的结构性损害,损害范围通常广泛,并均包含初级感觉运动区或辅助性感觉运动区.惊吓性癫痫多药物难治,手术治疗可取得较好的效果,明显改善患者的预后.

Abstract：

Objective To study the clinical, scalp and intracranial electroencephalogram (EEG) characteristics of startle epilepsy, and its outcome of surgical treatment. Methods The clinical data of 9 patients with startle epilepsy who were treated in our hospital were reviewed retrospectively. Their scalp and intracranial EEG, and MRI were investigated. Results All of the patients were diagnosed as startle epilepsy, and most of seizures were provoked by sudden unexpected stimuli. MRI showed extensive lesions in 8 cases, scalp EEC showed mulifocality or focal epilepsic discharge in all. Intracranial electrodes monitoring were performed in 2 patients to locate the epileptogenic zone. Five patients were treated surgically, 3 of them were operated with hemispherectomy, and 2 with focal cortex resection. During 6-30 months follow up, the seizure outcome were Engel I grade in 4,and Engel Ⅲ grade in 1. Conclusions Most of the patients with startle epilepsy has brain lesions involving the perisensorimotor or supplementary sensorimotor area, and were refractory. Resective surgery may get satisfactory outcome.     

Usefulness of intracranial EEG in the decision process for epilepsy surgery

BACKGROUND AND PURPOSE: In patients with discordant results, non-localizing EEG, or bitemporal seizure onset, intracranial monitoring is done to confirm the seizure onset. Our aim was to assess the yield of intracranial recordings in patients with different clinical scenarios. METHODS: The records of all patients who underwent prolonged intracranial EEG monitoring (IEM) at the London Health Sciences Centre, University of Western Ontario, Canada, between 1993 and 1999, identified using our EEG patient database in continuous use since December 1972, were reviewed. Patients were analyzed in the following groups according to perceived increasing degrees of uncertainty of epileptic zone localization-group 1: lesion on MRI congruent with focal ictal and interictal scalp EEG, but findings are subtle and of low level of certainty (n=13), group 2: focal MRI, focal ictal and multifocal interictal scalp EEG (n=11), group 3: focal MRI, non-localizing or incongruent scalp EEG (n=73), group 4: normal of multifocal MRI, focal ictal scalp EEG (n=11), group 5: multifocal MRI, non-localizing scalp EEG (n=18), and group 6: normal MRI, multifocal scalp EEG (n=36). RESULTS: One hundred and seventy one patients underwent IEM at the London Health Sciences Centre between 1993 and 1999. All patients had localization-related epilepsy, plus or minus secondary generalization. IEM was helpful overall in 86% of patients, in 69% of group 1, 36% of group 2, 90% of group 3, 81% of group 4, 100 of group 5 and 92% of group 6. CONCLUSIONS: Our study shows that the yield of the IEM was higher in the groups of patients with lack of congruence between the MRI and the scalp EEG. The yield was lower in patients with congruent but subtle or uncertain scalp EEG and MRI findings.     

颞叶癫痫发作初期头皮和颅内脑电定位价值的比较研究

目的 比较研究颞叶癫痫发作初期头皮脑电(sEEG)和颅内脑电(iEEG)的特点,探讨有定位意义的EEG指标.方法 常规行长程视频EEG(Video-EEG,V-EEG)监测,以捕捉到3次以上发作为标准.对sEEG难以定位的患者采用颅内埋置硬膜下和(或)深部电极,记录iEEG.结果 本组20例资料显示,sEEG和iEEG的定位检出率分别为50%和100%.经iEEG记录分析,7例sEEG不能定侧者5例完成定侧,10例广泛性sEEG异常者均定位为区域性或局限性表现.结论 低幅快节律、棘波和尖波节律具有重要的的定位价值;80%的sEEG低幅快节律表现者,与iEEG监测中表现一致;80%的sEEG颞叶棘波表现者,在iEEG监测中存在尖波节律.iEEG能明显提高致痫灶的定侧和定位准确性.     

Seizures lead to elevation of intracranial pressure in children undergoing invasive EEG monitoring

PURPOSE: To study the effects of intracranial subdural grid electrode placement and seizures on intracranial pressure (ICP) in children undergoing invasive EEG monitoring. METHODS: Sixteen children with pharmacoresistant epilepsy who underwent two-stage epilepsy surgery with subdural grid placement were included in the study. The ICP was recorded at baseline and with each seizure prospectively. A variety of seizure parameters including type of seizure, length of seizure, extent of seizure spread, and number of subdural grid electrodes inserted were analyzed retrospectively and correlated with the change in ICP. RESULTS: A total of 48 seizures in 16 children were studied. The mean baseline ICP correlated positively with age of the child. Generalized tonic-clonic seizures were associated with the highest rise in ICP. Similarly, ICP rise was associated with seizures involving more electrodes indicating a larger area of brain participating in the seizure. CONCLUSION: Seizures in general and generalized tonic-clonic seizures, in particular, increase ICP temporarily in patients who are undergoing invasive EEG monitoring with subdural grids.     

Localization of epileptogenic zone in temporal lobe epilepsy by ictal scalp EEG.

Our aim was to evaluate the ability to localize the epileptogenic zone in temporal lobe epilepsy (TLE) by ictal scalp electroencephalogram (EEG). Using simultaneous video recording, we analysed scalp EEG activity during ictal periods in 38 patients (30 patients with medial TLE (MTLE) and eight with lateral TLE (LTLE)). In 14 patients, intracranial ictal EEGs were recorded with depth electrodes, and simultaneous recordings of scalp and intracranial EEG were performed in 11 patients. Scalp EEG showed that, in all 30 patients with MTLE (71 of 72 seizures), an attenuation of background activity was observed before the appearance of ictal activity. Ictal discharges first appeared in the scalp EEG when the ictal discharges reached the lateral part of the temporal lobe on the intracranial EEG. While, in all eight patients with LTLE (25 of 25 seizures), the attenuation of background activity did not occur before the appearance of ictal activity. When the ictal discharges started in the lateral temporal lobe on intracranial EEG, ictal discharges appeared on the scalp. MTLE and LTLE could be diagnosed by the presence or absence of attenuation of background activity with clinical ictal signs before the appearance of ictal discharges.