脑皮层电刺激对功能区和癫痫发作起始区的确定作用

目的评估皮层电刺激功能区的确定的可靠性和对癫痫发作起始区的辅助定位作用。方法19名患者,在最怀疑的区域进行颅内电极置入,条状电极和格子电极均采用。颅内电极置入后,手术后关闭手术切口,患者返回脑电监测室进行1~2周的长程视频颅内脑电监测,期间对患者的发作间期和发作期脑电图进行分析和进行脑皮层电刺激功能区测定。皮层电刺激方式本临床实验采用的脑皮层电刺激参数是50Hz,0.2ms电脉冲刺激。结果脑皮层功能区测定19例患者中,发作起源区与重要的皮质功能区(运动、感觉、语言、视觉)范围紧邻或有重叠的有7例。脑皮层电刺激癫痫发作诱发19名患者中,18名患者人为通过颅内电极电刺激诱发出患者的发作先兆或发作,诱发脑皮质位置均包含皮层脑电记录所确定的癫痫发作起始区,电刺激诱发先兆或发作的可重复率为94.7%。手术并发症1例患者发生永久性局限视野缺损(术后7个月复查仍未改善),缺损为左上视野区;1例患者电极埋藏术后出现一过性失语,2天后该症状缓解,切除术后未发生失语;1例患者术后3天内反应时有“星星闪光”样视幻觉,后未经特殊处理,自愈。所有其他患者经过检查,术后无神经功能和神经心理损害发生。结论皮层电刺激确定的神经功能区可靠性好,是避免手术并发症的保证,同时电刺激对癫痫发作起始区的确定有良好的辅助作用。     

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。     

功能区肿瘤继发癫痫的手术治疗

目的总结我科近年来治疗功能区肿瘤继发癫痫的治疗经验,探讨功能区肿瘤继发癫痫的外科治疗原则和方法。方法对2011年5月-2013年5月在我院接受手术治疗的50例功能区肿瘤继发癫痫的患者进行回顾性分析。结果全组病例术前均行系统癫痫外科评估。其中12例行颅内电极皮层电刺激功能区定位,根据肿瘤大小和脑电图所监测到的致痫区以及皮层电刺激所确定的功能范围制定手术切除范围,术后1例出现对侧手指轻瘫,1例出现一过性对侧肢体偏瘫,1例出现一过性失语,其余术后随访无明显神经功能障碍。未行颅内埋藏电极患者38例,综合运用MRI、术中皮层脑电监测和术中B超等多种方法来确认手术切除范围,术后神经功能缺损术后加重5例,7例术后出现对侧肢体轻瘫,2例出现对侧偏麻,4例出现一过性失语。全组术后癫痫无发作达到EngelⅠ级42例（84％）。结论功能区肿瘤继发癫痫的外科治疗要兼顾肿瘤的全切、致痫灶的切除以及功能区的保护。术者的经验和熟练的显微操作是基本前提,术前综合运用多种评估方法,结合术中皮层脑电及术中B超等方法对病灶,致痫区以及功能区进行定位,对保证手术效果起重要作用。颅内埋藏电极长程脑电监测定位致痫灶,并经皮层电刺激定位功能区,可进一步明确病变与致痫灶、功能区重叠程度及毗邻关系,从而为手术切除范围的界定提供了关键信息。     

颅内电极置入与脑功能区定位技术在功能区难治性癫疒间手术的应用

目的探讨颅内电极埋藏与脑功能区定位技术在功能区起始的难治性癫疒间手术的评估价值。方法回顾性分析7例难治性癫疒间的临床资料,头皮视频脑电图长程监测均考虑致疒间灶可能累及功能区,故行颅内电极置入术,再行皮质电极视频脑电图长程监测,记录发作间期和发作期脑电图,以判断致疒间皮质,并采用皮质电刺激行脑功能区定位,在指导术中尽可能切除致疒间皮质的同时,最大限度保护脑功能。结果癫疒间发作起始区切除2例,癫疒间起始区部分切除加周围皮质热灼5例。随访6个月~1年,术后运动及语言功能均保护良好6例,对侧肢体出现短暂运动障碍后恢复1例。结论颅内电极埋藏与脑功能区定位技术是功能区难治性癫疒间手术必要评估手段,有助于术前明确脑功能区和皮质放电区域,以及两者之间的关系,指导设计手术方式,最大限度提高病人术后生活质量。     

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．     

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。     

脑磁图对颅内电极脑电图电极埋置的指导价值

目的 通过研究脑磁图(MEG)对侵入性颅内电极脑电图(icEEG)中电极埋置策略的影响,评价MEG在癫痫外科术前评估中的应用价值.方法 收集83例经临床发作症状学、电生理及影像学诊断为难治性部分性癫痫患者,根据MEG是否参与评估电极埋置策略分为两组,比较两组手术疗效的差异.手术疗效按照Engel疗效评价标准分级,Engel Ⅰ、Ⅱ、Ⅲ级为手术有效,Engel Ⅳ级为手术无效.结果 两组中,MEG未参与电极埋置策略评估的共43例,术后有效23例,占54％;而MEG参与评估电极埋置策略的共40例,术后有效31例,占78％,两组手术疗效差异有统计学意义(x2=5.256,P=0.022).结论 MEG能够指导电极埋置位置,增加发作起始区被电极覆盖的几率,提高颅内电极脑电监测的定位准确率,从而提高手术疗效.     

难治性枕叶癫痫的术前定位与手术治疗

目的探讨难治性枕叶癫痫的术前定位与手术方法。方法对经手术治疗且随访时间6个月以上的9例枕叶癫痫患者的临床资料进行回顾性分析。采用发作症状评估、影像学检查、长程视频头皮脑电图监测、颅内电极脑电图记录等方法综合术前定位。根据术前定位确定的致痫灶部位与范围采用不同的手术方法。7例病人采用颅内电极置入术来精确定位。局部枕叶皮层切除2例,枕叶大部或全部切除4例,全枕叶或后头部脑叶离断3例;同期经枕入路切除或离断颞叶内结结构3例。结果术后随访6个月至2年,术后癫痫无发作6例,发作1次1例,发作减少90%以上2例。结论难治性枕叶癫痫经手术治疗可以取得较好的疗效,颅内电极脑电图记录有助于致痫灶准确定位,并指导术中切除部位与功能保护。     

颅内电极脑电图监测技术在儿童癫痫手术中的应用

目的探讨颅内电极皮质脑电监测技术在儿童癫痫患者中的应用。方法回顾性分析2004年9月到2013年9月在我院接受颅内电极埋置手术的173例儿童癫痫患者的临床资料,总结其手术技术、并发症及术后效果。结果 173例儿童患者手术时平均年龄为(12.7±3.8)岁,颅内电极脑电图监测时间平均为(5.4±1.3)d,37例患者(21.4%)出现并发症,其中颅内血肿18例,脑水肿6例,脑脊液漏8例,术口感染3例,电极折断2例,颅骨骨髓炎3例,无永久性神经功能缺失患者。术后随访平均47个月±17个月,84例患者(48.9%)未再出现发作(Engel I级),41例(23.3%)发作显著减少(Engel II级)。结论长程颅内电极皮质脑电监测技术,有助于儿童癫痫患者的致痫灶定位诊断,提高手术疗效。合理制定电极埋置方案,注意操作细节及技巧,可降低颅内血肿等并发症的发生风险。     

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。     

Musicogenic seizures can arise from multiple temporal lobe foci: intracranial EEG analyses of three patients

PURPOSE: To determine the ictal-onset zone of musicogenic seizures by using intracranial EEG monitoring. METHODS: Musicogenic seizures in three patients with medically intractable musicogenic epilepsy were first localized by using noninvasive methods including, in one patient, ictal magnetoencephalography (MEG) and magnetic resonance spectroscopy (MRS). The ictal-onset zones in these patients were then further localized using by intracranial EEG monitoring, and the outcomes of the two patients who underwent epilepsy surgery were determined. RESULTS: Patient 1's musicogenic seizures localized to the right lateral temporal lobe, patient 2's originated in the right mesial temporal lobe, and patient 3's arose independently from both mesial temporal lobes. Patients 1 and 2 underwent resective epilepsy surgery and are seizure free (Engel class I). CONCLUSIONS: Musicogenic epilepsy is a heterogeneous syndrome with seizures that can arise from multiple temporal lobe foci. Patients with medically intractable musicogenic epilepsy and with unilateral ictal onset zones may be considered candidates for resective epilepsy surgery.     

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。     

Interictal EEG spikes identify the region of electrographic seizure onset in some,but not all,pediatric epilepsy patients

Purpose : The role of sharps and spikes, interictal epileptiform discharges (IEDs), in guiding epilepsy surgery in children remains controversial, particularly with intracranial electroencephalography (IEEG). Although ictal recording is the mainstay of localizing epileptic networks for surgical resection, current practice dictates removing regions generating frequent IEDs if they are near the ictal onset zone. Indeed, past studies suggest an inconsistent relationship between IED and seizure‐onset location, although these studies were based upon relatively short EEG epochs. Methods : We employ a previously validated, computerized spike detector to measure and localize IED activity over prolonged, representative segments of IEEG recorded from 19 children with intractable, mostly extratemporal lobe epilepsy. Approximately 8 h of IEEG, randomly selected 30‐min segments of continuous interictal IEEG per patient, were analyzed over all intracranial electrode contacts. Results : When spike frequency was averaged over the 16‐time segments, electrodes with the highest mean spike frequency were found to be within the seizure‐onset region in 11 of 19 patients. There was significant variability between individual 30‐min segments in these patients, indicating that large statistical samples of interictal activity were required for improved localization. Low‐voltage fast EEG at seizure onset was the only clinical factor predicting IED localization to the seizure‐onset region. Conclusions : Our data suggest that automated IED detection over multiple representative samples of IEEG may be of utility in planning epilepsy surgery for children with intractable epilepsy. Further research is required to better determine which patients may benefit from this technique a priori.     

Surgery for intractable epilepsy in children: pre- and perioperative evaluations with special reference to dipole tracing method estimated from interictal spike

Methods of preoperative and perioperative evaluation methods for surgical treatment of intractable epilepsy in children are described. Among non-invasive diagnostic methods, EEG-video monitoring is the most fundamental. Amygdalohippocampal volume measurement by MR was useful for the differential diagnosis of mesial temporal lobe epilepsy (TLE) from lateral TLE and generalized epilepsy. The dipole tracing method with a realistic head model was useful for identification of epileptic foci from the interictal spikes of scalp EEG, when an abnormal electric source was estimated as an equivalent current dipole (ECD) in the brain of patients with organic lesion and TLE. ECD concentration ratio ranged from 70 to 90% within 20 mm around the lesion. After lesionectomy seizures disappeared in every patient. The mean distance between the centers of the ECD and epileptic focus (identified by subdural electrode recording) was 14 mm (range: 8 to 18 mm). ECDs of mesial TLE were located in the temporal base rather than mesial temporal lobe, whereas those of lateral TLE in the lateral cortex precisely. In unilateral, intermediate and bilateral TLE, 76%, 52% and 36% of ECDs were localized in the ictal onset zone respectively (p = 0.007). Electrical cortical stimulation with chronically placed intracranial electrodes was used to accurately identify eloquent areas to avoid postsurgical complications. Immediately after operation, 10 to 20% of patients showed better or deteriorated results in neuropsychological examinations, which recovered in all patients after one year. Postoperative seizures were absent in three fourths of patients. Further efforts are needed to obtain better seizure control in future.     

Dynamic imaging of seizure activity in pediatric epilepsy patients

Objective

To investigate the feasibility of using noninvasive EEG source imaging approach to image continuous seizure activity in pediatric epilepsy patients.

Methods

Nine pediatric patients with medically intractable epilepsy were included in this study. Eight of the patients had extratemporal lobe epilepsy and one had temporal lobe epilepsy. All of the patients underwent resective surgery and seven of them underwent intracranial EEG (iEEG) monitoring. The ictal EEG was analyzed using a noninvasive dynamic seizure imaging (DSI) approach. The DSI approach separates scalp EEGs into independent components and extracts the spatio-temporal ictal features to achieve dynamic imaging of seizure sources. Surgical resection and intracranial recordings were used to validate the noninvasive imaging results.

Results

The DSI determined seizure onset zones (SOZs) in these patients were localized within or in close vicinity to the surgically resected region. In the seven patients with intracranial monitoring, the estimated seizure onset sources were concordant with the seizure onset zones of iEEG. The DSI also localized the multiple foci involved in the later seizure propagation, which were confirmed by the iEEG recordings.

Conclusions

Dynamic seizure imaging can noninvasively image the seizure activations in pediatric patients with both temporal and extratemporal lobe epilepsy.

Significance

EEG seizure imaging can potentially be used to noninvasively image the SOZs and aid the pre-surgical planning in pediatric epilepsy patients.     

Resection of ictal high-frequency oscillations leads to favorable surgical outcome in pediatric epilepsy

Purpose: Intracranial electroencephalography (EEG) is performed as part of an epilepsy surgery evaluation when noninvasive tests are incongruent or the putative seizure‐onset zone is near eloquent cortex. Determining the seizure‐onset zone using intracranial EEG has been conventionally based on identification of specific ictal patterns with visual inspection. High‐frequency oscillations (HFOs, >80 Hz) have been recognized recently as highly correlated with the epileptogenic zone. However, HFOs can be difficult to detect because of their low amplitude. Therefore, the prevalence of ictal HFOs and their role in localization of epileptogenic zone on intracranial EEG are unknown. Methods: We identified 48 patients who underwent surgical treatment after the surgical evaluation with intracranial EEG, and 44 patients met criteria for this retrospective study. Results were not used in surgical decision making. Intracranial EEG recordings were collected with a sampling rate of 2,000 Hz. Recordings were first inspected visually to determine ictal onset and then analyzed further with time‐frequency analysis. Forty‐one (93%) of 44 patients had ictal HFOs determined with time‐frequency analysis of intracranial EEG. Key Findings: Twenty‐two (54%) of the 41 patients with ictal HFOs had complete resection of HFO regions, regardless of frequency bands. Complete resection of HFOs (n = 22) resulted in a seizure‐free outcome in 18 (82%) of 22 patients, significantly higher than the seizure‐free outcome with incomplete HFO resection (4/19, 21%). Significance: Our study shows that ictal HFOs are commonly found with intracranial EEG in our population largely of children with cortical dysplasia, and have localizing value. The use of ictal HFOs may add more promising information compared to interictal HFOs because of the evidence of ictal propagation and followed by clinical aspect of seizures. Complete resection of HFOs is a favorable prognostic indicator for surgical outcome.     

Surgical treatment in startle epilepsy

This report presents a patient with medically intractable startle epilepsy who was treated with surgery. The ictal onset zone was further localized to a part of the premotor cortex on the basis of intracranial electroencephalography recording and surgical resection of the epileptogenic zone was done. The motor area close to the epileptogenic focus was localized using electrical cortical stimulation and thus preserved. Patient has been seizure-free postoperatively (Engel Class I) during the 18-month follow-up. The patient illustrates that surgery can be an option in patients with medically intractable startle epilepsy with well-defined unilateral epileptogenic zone.     

Ictal magnetoencephalography in temporal and extratemporal lobe epilepsy

PURPOSE: We evaluated visual patterns and source localization of ictal magnetoencephalography (MEG) in patients with intractable temporal lobe epilepsy (TLE) and extratemporal epilepsy (ETE). METHODS: We performed spike and seizure recording simultaneously with EEG and MEG on two patients with TLE and five patients with ETE. Scalp EEG was recorded from 21 channels (10-20 international system), whereas MEG was recorded from two 37-channel sensors. We compared ictal EEG and MEG onset, frequency, and evolution and performed MEG dipole source localization of interictal spikes and early ictal discharges and co-registered dipoles to brain magnetic resonance imaging (MRI). We correlated dipole characteristics with intracranial EEG, surgical resection, and outcome. RESULTS: Ictal MEG lateralized seizure onset in both TLE patients and demonstrated ictal onset, frequency, and evolution in accordance with EEG. Ictal MEG source analysis revealed tangential vertical dipoles in the anterolateral angle in one patient, and anterior dipoles with anteroposterior orientation in the other. Intracranial EEG revealed regional entorhinal seizure onset in the first patient. Both patients became seizure free after temporal lobectomy. In ETE, ictal MEG demonstrated visual patterns similar to ictal EEG and had concordant localization with interictal MEG in all five patients. Two patients underwent surgery. Ictal MEG localization was concordant with intracranial EEG in both cases. One patient had successful outcome after surgery. The second patient did not improve after limited resection and multiple subpial transections. CONCLUSIONS: Ictal MEG can demonstrate ictal onset frequency and evolution and provide useful localizing information before epilepsy surgery.     

Intracranial investigation of a patient with nodular heterotopia and hippocampal sclerosis: dealing with a dual pathology

The pre‐operative assessment and surgical management of patients with dual pathology is challenging. We describe a patient with drug‐resistant focal epilepsy with hippocampal sclerosis and extensive periventricular nodular heterotopia in the same hemisphere. The semiology, scalp EEG, and imaging were divergent, but the presence of focal interictal and ictal epileptic discharges of the putative ictal onset zone resulted in successful localization of the epileptogenic zone. A less aggressive resection was performed based on intracranial EEG recording. The patient has been seizure‐free for three years since resection. Electroclinical hypotheses and challenges in defining the epileptogenic network are discussed.