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。     

颅内电极脑电图监测对癫痫致痫灶的定位作用

目的探讨颅内电极脑电图（EEG）监测对癫痫致痫灶的定位作用。方法对经临床、影像学和常规EEG检查不能确定致痫灶部位的20例难治性颞叶癫痫患者，应用立体定向技术，经双侧颞叶植入硬膜下条状电极进行长时间EEG监测，观察发作期及发作间期EEG变化，结合常规EEG、MRI检查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20例患者颅内电极埋藏时间为1—5d，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。20例患者发作期颅内电极EEG均能准确定位，15例致痫灶发作间期与发作期一致，2例发作间期为双侧棘波，3例发作间期定位与发作期不一致。术后按Engel疗效分级：发作消失13例（65％），显著改善3例（15％），良好3例（15％），无效1例（5％）。未出现因颅内电极安置所致的并发症。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。     

难治性颞叶内侧癫痫术前评估方法再评价

目的 通过难治性颢叶内侧癫痫术后随访1年以上,术后效果达到Engel's Ⅰ级(无发作)的患者,探讨各种术前评估方法确定癫痫灶的可靠程度.方法 65名术后随访超过1年,术后达到Engel's Ⅰ级疗效的难治性颞叶内侧癫痫患者,患者的发作症状学、神经影像和头皮脑电图进行回顾性分析.结果 所有患者的发作间期正电子发射断层扫描(PET)显示与手术侧一致的颞叶低代谢改变;41例患者发作前存在典型的颞叶内侧常见先兆,所有患者发作起始表现为意识障碍;28例患者有手术侧颞叶影像异常(图1),8例患者存在双侧颞叶异常,8例患者存在多脑叶影像异常,21例患者核磁共振检查未发现明显异常;20%患者发作间期偶有异常、80%患者存在多灶棘波、尖波、棘慢波;发作期脑电放电早期显示:20例患者无法确定起源侧别,45例患者可以确定侧别(手术侧),只有21例患者可以清楚的显示手术侧蝶骨电极起源.结论 患者的发作症状学分析和PET检查是难治性颞叶内侧癫痫术前评估中基本和重要的评估手段.     

术前头皮长程视频脑电图表现与颞叶癫痫手术预后的关系

目的探讨术前头皮长程视频脑电图(VEEG)发作间期放电、发作期起始侧别与颞叶癫痫(TLE)患者手术预后的关系。方法回顾性分析75例颞叶癫痫手术治疗患者的临床资料。患者术后经过1~9年的随访,根据手术后有、无癫痫发作将患者分为发作组和无发作组。另外按两组患者中术前头皮脑电图发作间期放电及发作期起始侧别分组,比较各组患者中发作组与无发作组患者的比率。结果75例患者中术后有发作者34例(发作组),无发作者41例(无发作组)。术前头皮VEEG发作期起始单侧且发作间期同侧放电者24例,其中发作组4例、无发作组20例,差异有统计学意义(P<0.01)。手术侧别与影像证据同侧的72例患者中,发作组34例,无发作组38例;脑电图(发作期与发作间期)与影像证据一致患者中,发作组4例,未发作组20例,差异有统计学意义(P<0.01)。症状学与影像学表现一致的49例患者中,发作组22例,无发作组27例;与发作期及发作间期脑电均一致患者中,发作组3例,无发作组17例,差异有统计学意义(P<0.05)。结论术前VEEG发作期起始为单侧且与发作间期放电同侧、手术侧别与影像学异常同侧且VEEG(发作期与发作间期)与影像学异常一致,以及术前影像学、症状学和VEEG表现三者一致的颞叶癫痫患者手术治疗的预后较好。     

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.     

颞叶癫痫视频脑电图53例分析

目的分析53例颞叶癫痫(TLE)患者视频脑电图(VEEG)表现,为TLE诊断、定位和治疗提供参考。方法系统分析昆明医科大学附属延安医院2011年10月至2016年12月收治的53例TLE患者VEEG资料,总结其背景活动异常、发作间期、发作期VEEG特点。结果 22例(41.5%)出现背景活动异常,且多见于内侧颞叶癫痫(MTLE);发作期与发作间期异常放电波形以尖波、棘波、尖慢波为主;MTLE异常放电部位主要分布于前颞区,外侧颞叶癫痫(LTLE)异常放电主要分布于中后颞区。结论VEEG中的背景活动异常、发作间期、发作期的异常放电波形、部位等特征性表现有助于TLE的诊断、定位和治疗。     

颅内电极脑电图监测对癫(癎)致(癎)灶的定位作用

目的探讨颅内电极脑电图(EEG)监测对癫致灶的定位作用。方法对经临床、影像学和常规EEG检查不能确定致灶部位的20例难治性颞叶癫患者,应用立体定向技术,经双侧颞叶植入硬膜下条状电极进行长时间EEG监测,观察发作期及发作间期EEG变化,结合常规EEG、MRI检查结果对癫灶进行综合定位;术后随访,评估致灶定位的准确性。结果20例患者颅内电极埋藏时间为1～5d,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。20例患者发作期颅内电极EEG均能准确定位,15例致灶发作间期与发作期一致,2例发作间期为双侧棘波,3例发作间期定位与发作期不一致。术后按Engel疗效分级:发作消失13例(65%),显著改善3例(15%),良好3例(15%),无效1例(5%)。未出现因颅内电极安置所致的并发症。结论颅内电极EEG监测可为癫手术治疗提供可靠的病灶定位依据。     

耐药性颞叶内侧癫痫发作前期海马脑电特征分析

目的 观察耐药性颞叶内侧癫痫患者发作前期海马电极脑电活动特点,为判断和切除癫痫病灶提供神经电生理学依据.方法 对16例非侵入性手段难以明确病灶的耐药性颞叶内侧癫痫患者进行双侧海马电极监测,患者停用抗癫痫药在非麻醉状态下监测48～72 h,分析癫痫发作前期海马电极脑电图资料,探讨耐药性颞叶内侧癫痫发作前期海马电极脑电活动特点.结果 16例发作间期记录到背景活动基础上出现局限于某几个电极点的阵发性高幅慢波1例、发作性快波节律1例、棘波或棘尖慢复合波14例,视为异常脑电活动;经过48～ 72 h监测,10例监测到33次临床癫痫发作,发作起始期海马电极均可记录到清晰可辨的癫痫样脑电波形.结论 颞叶内侧癫痫临床发作起始期海马电极癫痫样放电清晰可辨,部位局限,易于确定癫痫性活动起源部位.对于非侵入性手段难以判断癫痫样放电起源的颞叶内侧癫痫可采用脑立体定向技术植入海马深部电极进行脑电监测.     

VEEG、ECoG、结合MRS定位致痫灶评价(附23例临床分析)

目的探讨在颞叶病变继发颞叶癫痫(Temporal lobe epilepsy,TLE)患者中应用长程视频脑电图(VEEG)、颅脑磁共振波谱分析(MRS)联合皮层脑电图(ECoG综合定位致痫灶指导手术切除致痫灶范围,评价TLE术后临床效果。方法病历资料选自2016年1月至2017年12月期间在蚌埠市第三人民医院癫痫研究所就医的既往有癫痫发作临床症状及不同医院脑电图结果提示有颞叶脑电异常初步依据纳入、排除标准选取病历资料完整的23例颞叶病变继发TLE的患者行手术治疗,术前完善VEEG及MRS检查,术中联合ECoG再检测致痫灶指导手术切除范围,术后采用Engel标准评价手术效果。结果应用VEEG与MRS两种检查分别阳性对不同病因组患者致痫灶定位中,术中在ECoG再检测指导下与MRS、VEEG定位致痫灶比较,MRS与ECoG一致率为95.65%,高于VEEG与ECoG的一致率65.22%,差异有统计学意义(χ~2=6.769,P0.05);在ECoG再检测指导下手术治疗的23例继发性TLE患者,术后随访12～27个月,依据Engel评价标准,结果示:EngelⅠ级18例,EngelⅡ级3例,EngelⅢ级1例,EngelⅣ级1例,术后均无严重并发症及死亡病例,术后临床效果达到显著有效共22例,显著有效率为95.65%。结论术中联合ECoG再检测致痫灶并指导手术切除范围,可显著提高手术治疗效果,TLE患者术后显著有效达95.65%;对一般经济条件需要手术治疗的患者,术前应用MRS与VEEG综合定位致痫灶与术中联合ECoG再检测致痫灶是颞叶病变继发TLE患者一种很好的选择,可避免昂贵的检查费用,获得满意疗效。     

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。     

脑穿通畸形相关性癫(癎)的手术治疗(附12例分析)

目的 评价外科切除致(癎)皮质治疗脑穿通畸形相关性顽固性癫(癎)的疗效.方法 回顾性分析12例脑穿通畸形病人的临床特征、电生理数据、术中所见及致(癎)皮质切除后的癫(癎)发作情况.本组均为部分性发作,继发全面性发作9例,复杂部分性发作3例.长程视频脑电图(VEEG)显示:发作间期VEEG异常与囊肿位置吻合7例,分布弥散5例;发作期VEEG异常6例,其中5例与囊肿位置吻合.对术前VEEG和术中皮质脑电图(ECoG)显示的间期异常区、可能的症状区、硬化皮质和磁共振流体抑制翻转复原序列(MRI-flair像)上的高信号区等予以切除.结果 随访6个月～7年,本组均获Engel Ⅰ级控制,其中2例仍有先兆发作.无并发症发生.结论 在脑穿通畸形病人中,致(癎)灶不仅涉及电生理异常区(包括术前VEEG及术中ECoG异常区),也可能涉及解剖异常区(包括术前MRI-flair像上的高信号区及术中所见硬化皮质).这些异常区的充分切除和功能区的确切保护为脑穿通畸形性顽固性癫(癎)的外科治疗提供了一个有效的办法.     

The value of intraoperative electrocorticography in surgical decision making for temporal lobe epilepsy with normal MRI

Purpose: We hypothesized that acute intraoperative electrocorticography (ECoG) might identify a subset of patients with magnetic resonance imaging (MRI)–negative temporal lobe epilepsy (TLE) who could proceed directly to standard anteromesial resection (SAMR), obviating the need for chronic electrode implantation to guide resection. Methods: Patients with TLE and a normal MRI who underwent acute ECoG prior to chronic electrode recording of ictal onsets were evaluated. Intraoperative interictal spikes were classified as mesial (M), lateral (L), or mesial/lateral (ML). Results of the acute ECoG were correlated with the ictal‐onset zone following chronic ECoG. Onsets were also classified as “M,”“L,” or “ML.” Positron emission tomography (PET), scalp‐EEG (electroencephalography), and Wada were evaluated as adjuncts. Key Findings: Sixteen patients fit criteria for inclusion. Outcomes were Engel class I in nine patients, Engel II in two, Engel III in four, and Engel IV in one. Mean postoperative follow‐up was 45.2 months. Scalp EEG and PET correlated with ictal onsets in 69% and 64% of patients, respectively. Wada correlated with onsets in 47% of patients. Acute intraoperative ECoG correlated with seizure onsets on chronic ECoG in all 16 patients. All eight patients with “M” pattern ECoG underwent SAMR, and six (75%) experienced Engel class I outcomes. Three of eight patients with “L” or “ML” onsets (38%) had Engel class I outcomes. Significance: Intraoperative ECoG may be useful in identifying a subset of patients with MRI‐negative TLE who will benefit from SAMR without chronic implantation of electrodes. These patients have uniquely mesial interictal spikes and can go on to have improved postoperative seizure‐free outcomes.     

Two magneto-encephalographic epileptic foci did not coincide with the electrocorticographic ictal onset zone in a patient with temporal lobe epilepsy.

To evaluate the usefulness and limitations of magneto-encephalography (MEG) for epilepsy surgery, we compared 'interictal' epileptic spike fields on MEG with ictal electrocorticography (ECoG) using invasive chronic subdural electrodes in a patient with intractable medial temporal lobe epilepsy (MTLE) associated with vitamin K deficiency intracerebral hemorrhage. A 19-year-old male with an 8-year history of refractory complex partial seizures, secondarily generalized, and right hemispheric atrophy and porencephaly in the right frontal lobe on MRI, was studied with MEG to define the interictal paroxysmal sources based on the single-dipole model. This was followed by invasive ECoG monitoring to delineate the epileptogenic zone. MEG demonstrated two paroxysmal foci, one each on the right lateral temporal and frontal lobes. Ictal ECoG recordings revealed an ictal onset zone on the right medial temporal lobe, which was different from that defined by MEG. Anterior temporal lobectomy with hippocampectomy was performed and the patient has been seizure free for two years. Our results indicate that interictal MEG does not always define the epileptogenic zone in patients with MTLE.     

Epilepsy with temporal encephalocele: Characteristics of electrocorticography and surgical outcome

Temporal lobe encephaloceles (TEs) are increasingly identified in patients with epilepsy due to advances in neuroimaging. Select patients become seizure‐free with lesionectomy. In practice, however, many of these patients will undergo standard anterior temporal lobectomy. Herein we report on the first series of patients with refractory temporal lobe epilepsy (TLE) with encephalocele to undergo chronic or intraoperative electrocorticography (ECoG) in order to characterize the putative epileptogenic nature of these lesions and help guide surgical planning. This retrospective study includes nine adult patients with magnetic resonance imaging/computed tomography (MRI/CT)–defined temporal encephalocele treated between 2007 and 2014 at University of California San Francisco (UCSF). Clinical features, ECoG, imaging, and surgical outcomes are reviewed. Six patients underwent resective epilepsy surgery. Each case demonstrated abnormal epileptiform discharges around the cortical area of the encephalocele. Two underwent tailored lesionectomy and four underwent lesionectomy plus anterior medial temporal resection. Postoperatively, five patients, including both with lesionectomy only, had Engel class Ia surgical outcome, and one had a class IIb surgical outcome. The role of TE in the pathogenesis of epilepsy is uncertain. ECoG can confirm the presence of interictal epileptiform discharges and seizures arising from these lesions. Patients overall had a very good surgical prognosis, even with selective surgical approaches.     

脑电偶极子分析在痫灶切除术中的定位价值

目的探讨长程视频脑电监测和偶极子分析在痫灶切除术中的定位价值。方法对35例开颅痫灶切除术患者术前行常规脑电和长程视频脑电监测,脑电痫性放电进行偶极子分析,并与手术中硬膜下电极记录的脑电相对照。结果35例患者视频脑电图监测异常35例,有痫性放电者35例;常规脑电图异常28例,有痫性放电者18例;行常规脑电图监测无典型癫痫发作出现。两者之间脑电异常率、痫性放电阳性率、典型临床发作率都有统计学意义。以术中硬膜下电极记录为标准,头皮脑电偶极子定位异常放电灶的准确率为97%,切除病灶病理检查异常率86%。偶极子定位误差一般<15mm。结论长程视频脑电监测和头皮脑电偶极子定位癫痫起源灶可为开颅痫灶切除手术提供有价值的信息。     

Surgical outcome and prognostic factors of cryptogenic neocortical epilepsy

Surgical treatment of cryptogenic neocortical epilepsy is challenging. The aim of this study was to evaluate surgical outcomes and to identify possible prognostic factors including the results of various diagnostic tools. Eighty-nine patients with neocortical epilepsy with normal magnetic resonance imaging (35 patients with frontal lobe epilepsy, 31 with neocortical temporal lobe epilepsy, 11 with occipital lobe epilepsy, 11 with parietal lobe epilepsy, and 1 with multifocal epilepsy) underwent invasive study and focal surgical resection. Patients were observed for at least 2 years after surgery. The localizing values of interictal electroencephalogram (EEG), ictal scalp EEG, interictal 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and subtraction ictal single-photon emission computed tomography were evaluated. Seventy-one patients (80.0%) had a good surgical outcome (Engel class 1-3); 42 patients were seizure free. Diagnostic sensitivities of interictal EEG, ictal scalp EEG, FDG-PET, and subtraction ictal single-photon emission computed tomography were 37.1%, 70.8%, 44.3%, and 41.1%, respectively. Localization by FDG-PET and interictal EEG was correlated with a seizure-free outcome. The localizing value of FDG-PET was greatest in neocortical temporal lobe epilepsy. The focalization of ictal onset and also ictal onset frequency in invasive studies were not related to surgical outcome. Concordance with two or more presurgical evaluations was significantly related to a seizure-free outcome.     

Interictal regional delta slowing is an EEG marker of epileptic network in temporal lobe epilepsy

Purpose: Several studies have suggested that interictal regional delta slowing (IRDS) carries a lateralizing and localizing value similar to interictal spikes and is associated with favorable surgical outcomes in patients with temporal lobe epilepsy (TLE). However, whether IRDS reflects structural dysfunction or underlying epileptic activity remains controversial. The objective of this study is to determine the cortical electroencephalography (EEG) correlates of scalp‐recorded IRDS, in so doing, to further understand its clinical and biologic significances. Methods: We examined the cortical EEG substrates of IRDS with electrocorticography (ECoG‐IRDS) and delineated the spatiotemporal relationship between ECoG‐IRDS and both interictal and ictal discharges by recording simultaneously scalp and intracranial EEG in 18 presurgical candidates with TLE. Key Findings: Our results demonstrated that ECoG‐IRDS is typically a mixture of delta/theta slowing and spike‐wave potentials. ECoG‐IRDS was predominantly recorded from basal and anterolateral temporal cortex, occasionally in mesial, posterior temporal, and extratemporal regions. Abundant IRDS was most commonly observed in patients with neocortical temporal lobe epilepsy (NTLE), whereas infrequent to moderate IRDS was usually observed in patients with mesial temporal lobe epilepsy (MTLE). The anatomic distribution of ECoG‐IRDS was highly correlated with the irritative and seizure‐onset zones in 10 patients with NTLE. However, it was poorly correlated with the irritative and seizure‐onset zones in the 8 patients with MTLE. Significance: These findings demonstrate that IRDS is an EEG marker of epileptic network in patients with TLE. Although IRDS and interictal/ictal discharges likely arise from the same neocortical generator in patients with NTLE, IRDS in patients with MTLE may reflect a network disease that involves temporal neocortex.     

Ictal and Interictal Activity in Partial Epilepsy Recorded with Multichannel Magnetoelectroencephalography: Correlation of Electroencephalography/Electrocorticography, Magnetic Resonance Imaging, Single Photon Emission Computed Tomography, and Positron Emission Tomography Findings

Ictal and interictal epileptic activity was recorded for the first time by multichannel magnetoencephalography (MEG) in three patients with partial epilepsy. Pre- and intra-operative localization of the epileptogenic region was compared. The interictal epileptic activity was localized at the same region of the temporal or frontal lobe as the ictal activity. Main zones of ictal activity were shown to evolve from the tissue at the centers of interictal activity. Pre- and intra-operative electrocorticography (ECoG) as well as postoperative outcome confirmed localization in the temporal and frontal lobe. Results also correlated with findings from scalp EEG, interictal and ictal single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance imaging (MRI). Combined multichannel MEG/EEG recording permitted dipole localization of interictal and ictal activity.     

Extent of neocortical resection and surgical outcome of epilepsy: Intracranial EEG analysis

Purpose: Intracranial electroencephalography (EEG) monitoring is an important process in the presurgical evaluation for epilepsy surgery. The objective of this study was to identify the ideal resection margin in neocortical epilepsy guided by subdural electrodes. For this purpose, we investigated the relationship between the extent of resection guided by subdural electrodes and the outcome of epilepsy surgery. Methods: Intracranial EEG studies were analyzed in 177 consecutive patients who had undergone resective epilepsy surgery. We reviewed various intracranial EEG findings and resection extent. We analyzed the relationships between the surgical outcomes and intracranial EEG factors: the frequency, morphology, and distribution of ictal‐onset discharges, the propagation speed, and the time lag between clinical and intracranial ictal onset. We also investigated whether the extent of resection, including the area showing ictal rhythm and various interictal abnormalities—such as frequent interictal spikes, pathologic delta waves, and paroxysmal fast activity—influenced the surgical outcome. Results: Seventy‐five patients (42%) were seizure free. A seizure‐free outcome was significantly associated with a resection that included the area showing ictal spreading rhythm during the first 3 s or included all the electrodes showing pathologic delta waves or frequent interictal spikes. However, subgroup analysis revealed that the extent of resection did not affect the surgical outcome in lateral temporal lobe epilepsy. Conclusions: The extent of resection is closely associated with surgical outcome, especially in extratemporal lobe epilepsy. Resection that includes the area with total pathologic delta waves and frequent interictal spikes predicts a good surgical outcome.     

Epilepsy surgery outcomes in temporal lobe epilepsy with a normal MRI

Purpose:   To determine the long-term efficacy of anterior temporal lobectomy for medically refractory temporal lobe epilepsy in patients with nonlesional magnetic resonance imaging (MRI).
Methods:   We identified a retrospective cohort of 44 patients with a nonlesional modern "seizure protocol" MRI who underwent anterior temporal lobectomy for treatment of medically refractory partial epilepsy. Postoperative seizure freedom was determined by Kaplan-Meyer survival analysis. Noninvasive preoperative diagnostic factors potentially associated with excellent surgical outcome were examined by univariate analysis in the 40 patients with follow-up of >1 year.
Results:   Engel class I outcomes (free of disabling seizures) were observed in 60% (24 of 40) patients. Preoperative factors associated with Engel class I outcome were: (1) absence of contralateral or extratemporal interictal epileptiform discharges, (2) subtraction ictal single photon emission computed tomography (SPECT) Coregistered to MRI (SISCOM) abnormality localized to the resection site, and (3) subtle nonspecific MRI findings in the mesial temporal lobe concordant to the resection.
Discussion:   In carefully selected patients with temporal lobe epilepsy and a nonlesional MRI, anterior temporal lobectomy can often render patients free of disabling seizures. This favorable rate of surgical success is likely due to the detection of concordant abnormalities that indicate unilateral temporal lobe epilepsy in patients with nonlesional MRI.