Presurgical evaluation and surgical outcome of temporal lobe epilepsy

The authors analyzed 22 patients younger than 18 years of age with temporal lobe epilepsy (TLE) treated surgically. Patients underwent a comprehensive presurgical evaluation, including video-electroencephalogram. Fifty-five percent had a history of febrile seizures. Eighty-two percent had auraes and most exhibited oroalimentary and gestural automatisms. Contralateral dystonic posturing was present in 36% and postictal dysphasia in 54% of patients with left-sided resections. Cranial magnetic resonance imaging (MRI) was abnormal in 59% of patients. MRI revealed changes consistent with mesial temporal sclerosis in 8 (47%) of 17 patients without lesions. Fluorodeoxyglucose-positron emission tomography (PET) scans revealed ipsilateral temporal hypometabolism (PET-TH) in 12 (85.7%) of 14 patients. The intracarotid amobarbital procedure revealed impaired memory of the epileptogenic side in 59% of patients. Seventeen patients underwent en-bloc resections and five lesionectomies and resection of the epileptogenic area. There was no surgical morbidity or mortality. Forty-three percent had hippocampal sclerosis, 28.5% gliosis, 14% low-grade tumors, 9.5% cavernous angiomas, and 5% had no pathologic findings. Follow-up (6 months to 12 years) was available for 21 patients; 76% became seizure free, 19% had rare seizures, and 5% had a worthwhile improvement. TLE can be safely treated surgically in younger patients with excellent results. The clinical manifestations were similar to adult patients. PET-TH was present even at a younger age, suggesting that the focal functional deficits appear early in patients with medically refractory TLE, which may help in the early identification of these patients.     

Neocortical temporal lobe epilepsy: intracranial EEG features and surgical outcome.

Patients with neocortical temporal lobe epilepsy (NTLE) may have less favorable outcome with anterior temporal lobectomy than those with mesial temporal foci. The authors analyzed ictal intracranial electroencephalograms (EEGs) in patients with NTLE to identify features that predict surgical outcome. The following intracranial ictal EEG features in 31 consecutive medically intractable NTLE patients were studied: Frequency (i.e., low-voltage fast [>20 Hz], recruiting ictal-onset spikes, ictal-onset rhythms less than 5 Hz, ictal-onset rhythms with repetitive sharp waves between 5 and 20 Hz); extent of ictal onset (focal, sublobar, and lobar); localization within the temporal lobe (anterior, posterior, or regional); and the time to seizure spread outside the temporal lobe (rapid, intermediate, and slow). The average follow-up period was 36.7 months (range, 18 to 60 months). Findings between two outcome groups were compared: class I group (seizure-free) and class II to IV group (persistent seizures). Twenty-one (66.7%) of 31 patients with NTLE were seizure-free. Intracranial EEG features which were significantly associated with seizure-free outcome were focal or sublobar onset, anterior temporal onset, and slow propagation time (P < 0.05). There was a trend for patients with ictal onset morphologies of slow ictal-onset rhythm and repetitive sharp waves to be seizure-free (P = 0.07). Intracranial EEG is helpful in predicting surgical outcome in NTLE patients.     

Electric source imaging in temporal lobe epilepsy.

The objective of this study was to determine the validity of interictal spike (IIS) source localization in temporal lobe epilepsies (TLE) using stereoelectroencephalography as a validating method. Twenty patients with drug-resistant TLE were studied with high-resolution EEG and stereoelectroencephalography. Sixty-four scalp channels, a realistic head model, and different algorithms were used. For each patient, the intracerebral interictal distribution was studied and classified into one of three groups: L (mainly lateral), ML (mediolateral), and M (medial). In group L (three patients), surface IIS were recorded with a high signal-to-noise ratio. Source localizations designated all or part of the intracerebral interictal distribution. In group ML (11 patients), 8 patients had surface IIS, only 5 of which were localizable. High-resolution EEG permitted localization of the more lateral portion and definition of its rostrocaudal extension. A common pattern was identified in three patients with a predominant role of the temporal pole. In group M (six patients), four patients had rare surface IIS, none of which were localizable. Surface EEG does not record IIS limited to medial temporal lobe structures. In TLE with a mediolateral or a lateral interictal distribution, only the lateral component is detectable on surface EEG and accurately localizable by source localization tools.     

1H MRSI predicts surgical outcome in MRI-negative temporal lobe epilepsy

1H MRS imaging (MRSI) was performed on 15 patients with MRI-negative temporal lobe epilepsy (TLE) who underwent seizure surgery. The non-seizure-free patients (NSF) ipsilateral hippocampal N-acetylaspartate (NAA)/(Cr+Cho) z scores were lower than the contralateral scores (p = 0.04), and the NSF ipsilateral z scores were lower than the seizure-free patients' (SF) ipsilateral z scores (p = 0.0049). Similarly, NSF contralateral scores were lower than contralateral SF (p = 0.02). These findings suggest NAA predicts the surgical outcome in patients with TLE without evidence of mesial temporal sclerosis on MRI.     

Predicting surgical outcome in temporal lobe epilepsy patients using MRI and MRSI

OBJECTIVE: To develop a classifier that uses MR data to predict surgical outcome in patients with temporal lobe epilepsy (TLE). METHODS: Eighty-one patients with medically refractory TLE who underwent surgical treatment were studied. Patients underwent comprehensive presurgical investigation, including ictal video-EEG recording, 1H MRS imaging, and volumetric MRI. Outcome was measured using Engel's classification system, condensed into two outcome groups. Two approaches were taken. First, outcome was defined as experiencing worthwhile improvement with >90% reduction of seizure frequency (Classes I, II, and III) or not (Class IV). A second approach was to define outcome as experiencing freedom from seizures following surgery (Class I) or not (Classes II, III, and IV). For each approach, a Bayesian classifier was constructed to predict outcome by calculating the probability of a patient's pattern of results from spectroscopic analysis of the temporal lobes and volumetric analysis of the amygdala and hippocampus being associated with the various outcome groups. RESULTS: The worthwhile improvement classifier correctly predicted the surgical outcomes of 60 of 65 (92%) of patients who experienced worthwhile improvement and 10 of 16 (63%) of patients who did not. The seizure-free classifier correctly predicted the surgical outcomes of 39 of 52 (75%) of patients who became seizure free and 21 of 29 (72%) of patients who did not. CONCLUSION: MR features are important markers of surgical outcome in patients with TLE and can provide assistance in identifying surgical candidates.     

颞叶癫痫手术效果与术前综合定位手段的相关分析

目的 探讨颞叶癫痫手术治疗效果与多种术前定位方法的相关关系.方法 选择2001年9月～2008年9月在我院行颞叶切除的癫痫患者99例,随访1～6年,按Engle预后分级,Ⅰ级:65例,Ⅱ级10例,Ⅲ级9例,Ⅳ级15例,Ⅰ～Ⅱ级为预后良好,分析这组病例的术前定位方法与手术效果的关系,确定其预测价值.结果 (1)发作间期脑电图颞区有局限慢波的48例患者中41例(85.4%)手术疗效好,无局限性慢波的27例中17例(63%)手术效果好,两者之间有显著性差异(χ2=4.97,P=0.027);(2)脑电图发作间期蝶骨电极单侧尖波57例中,效果好的47例(83%),双侧尖波18例,效果好11例(61%),两组之间无显著性差异(χ2=3.566,P=0.063);(3)发作期起始脑电图表现形式一致的56例中,效果好47例(84%),表现不一致的12例中4例(33%)手术效果好,两者之间有显著性差异(χ2=13.5,P=0.001);(4)发作极期脑电图:发作过程中脑电图无扩展的23例中14例(60%)手术效果好;脑电图向手术切除侧同侧扩展的39例中34例(87%)疗效好;向对侧扩展的6例中3例(50%)效果好,三者之间显著性差异(χ2=7.535,P=0.023);(5)头颅MRI与手术效果:82例患者的头颅MRI:未见结构异常7例中6例(85.7%)效果好,单侧颞区萎缩的10例中4例(40%)效果好,海马硬化的27例中24例(88.9%)效果好,颞区有明显结构异常的18例中13例(72.2%)效果较好,其他部位异常信号的20例中17例(85%)效果好,显示不同MRI改变之间的手术效果有显著性差异(χ2=11.463,P<0.02);(6)埋置颅内电极的20例中9例(45%)效果较好,未埋置颅内电极79例中66例(80%)效果好,二者之间有显著性差异(χ2=16.36,P=0.001);(7)其他:手术切除的侧别、发作症状和有无继发性的全面发作均与手术效果无明显的相关性.结论 颞叶癫痫手术切除效果与头颅MRI的结构改变有关;放置颅内电极与未放置颅内电极的手术效果有明显的差异,并与放置颅内电极的病例定位难度较大有关;颞叶切除的手术效果与患者不同次发作期脑电图改变是否一致有明显的相关性,发作起始期脑电图改变方式一致的手术效果较不一致的效果好;发作间期背景无局限性慢波、有局限性慢波的手术疗效之间有显著性差异,有慢波的手术疗效好,而发作间期的颞区尖波不能预测手术效果.     

Long-term follow-up outcome after surgical treatment for lesional temporal lobe epilepsy

OBJECTIVES: Lateral or neocortical temporal lobe epilepsy (TLE) is regarded as a distinct clinical entity from medial TLE. Surgery for neocortical TLE can be considered as a viable treatment option; however, there is very limited information available on aspects such as long-term seizure outcome. Thus, we retrospectively reviewed our ten surgical cases of lateral TLE with a minimum 2 year follow-up outcome. METHODS: The series comprised four male and six female patients, ranging in age from 3 to 46 years (mean: 28.8 years). Seven cases were found to be drug-resistant. Invasive pre-surgical evaluation for intractable epilepsy was performed in six patients. RESULTS: The pathologic lesions were removed completely in nine cases. Lesionectomy alone was performed in four cases and total epileptogenic focus resection was confirmed in four cases. The epileptogenic regions within eloquent areas were preserved in two cases. The medial temporal structure was intact and preserved in all cases. Neuropathologic diagnoses were cavernoma in three cases, astrocytoma (grade 2) in two cases, arteriovenous malformation in two cases, gliosis in two cases and ganglioglioma in one case. The mean duration of follow-up was 6.5 years (range: 2.2-9.3 years). Outcomes categorized according to Engel classes were class I (E1) in six cases and class II (E2) in four cases. Patients who had post-operative seizures may also achieve long-term seizure decrease or freedom in three cases: case 5 (E4-E2), case 6 (E4-E2) and case 7 (E3-E1). Thus, worthwhile improvement was achieved in 100% of the cases in this series, with 60% of patients being seizure-free during the followed-up period. CONCLUSIONS: The controlled long-term follow-up results suggested that surgery for lesional TLE can be considered as a viable treatment option to control seizure with a low morbidity rate and good outcomes.     

Dipole source localization of interictal epileptiform activity in temporal lobe epilepsy with medial temporal lesion

Dipole sources of interictal epileptiform activities recorded by conventional electroencephalogram (EEG) were estimated using the dipole tracing method. Four cases of temporal lobe epilepsy with medial temporal lesions were studied. Two patients with hippocampal sclerosis, one patient with granulation in the hippocampus and one patient with cavernous angioma were involved in the study. Interictal epileptiform activities were classified into two patterns according to the topography of spikes. They were widespread spikes over the parasagittal electrodes (parasagittal spikes) and restricted spikes at the temporal electrodes (temporal spikes). Dipole sources of parasagittal spikes were localized in the medio-basal temporal lobe with vertically orientated vector moment. Dipole sources of temporal spikes were localized in the medio-basal temporal lobe with horizontally orientated vector moment. Locations of dipoles and directions of vector moments were consistent with topography and polarity of spikes. The difference in the two patterns of interictal epileptiform activities was derived from the difference in the direction of the vector moment of dipole sources. There was no difference in the location of dipole sources. Both the dipole sources and the lesions were localized in the same medio-basal temporal lobe. Dipole tracing was very useful in localizing the dipole sources of interictal epileptiform activities and in understanding the neurophysiological background.     

Clinical characteristics and surgical outcome of patients with temporal lobe tumors and epilepsy

This is a retrospective study of 21 surgically treated patients with temporal lobe tumors and epilepsy. Evaluation included clinical data, EEG findings, structural scans, pathological diagnosis and post-surgical follow-up. There were 9 cases of ganglioglioma, 5 pilocytic astrocytoma, 3 ganglioneuroma, 2 dysembryoplastic neuroepithelial tumor, 1 pleomorphic xantoastrocytoma, and 1 meningioangiomatosis. Mean follow-up time was 22 months and outcome was evaluated according to Engel's classification; 76.2% were classified in class I and 23.8% in II and III. All patients classes II and III had been submitted to mesial and neocortical resections. There were no differences related to clinical characteristics, pathological diagnosis or duration of follow-up in patients seizure-free or not. All patients had abnormal MRI and ten of these had normal CT; the MRI characteristics were compared to pathological diagnosis and specific histological characteristics of the tumors were not discernible by MRI. We concluded that MRI was essential for the diagnosis and precise location of TL tumors. Ganglioglioma was the most frequent tumor and lesionectomy associated to mesial resection doesn't guarantee a better prognosis.     

颞叶癫痫术前评估对手术效果的影响

目的探讨神经影像学及神经电生理学资料在颞叶癫痫术前评估中的作用。方法回顾性分析63例吉林大学第一附属医院自2013年1月-2015年1月收治的颞叶癫痫患者术前神经影像学及神经电生理学的临床资料,确定手术切除范围,随访手术效果。结果长程视频脑电(V-EEG)结果显示,异常放电一侧占优势患者53例,术后随访均为EngelⅠ-Ⅱ级。头部MRI检查提示一侧颞区结构性病变(包括海马硬化)58例,术后随访EngelⅠ-Ⅱ级为55例。所有患者术后随访3~12个月,EngelⅠ级43例,EngelⅡ级12例,EngelⅢ级4例,EngelⅣ级4例,疗效满意。结论术前长程视频脑电(V-EEG)、头部MRI检查在颞叶癫痫术前定位中非常重要,而二者相结合,必要时辅以颅内电极EEG定位,是准确、可靠的癫痫灶定位方法。     

Postoperative EEG and seizure outcome in temporal lobe epilepsy surgery.

OBJECTIVE: To assess the prognostic value of scalp electroencephalogram (EEG) after epilepsy surgery, we investigated whether postoperative EEG abnormalities (interictal epileptiform discharges, IED; interictal slow activity, ISA) were associated with seizure outcome and other patient characteristics after resective surgery in patients with temporal lobe epilepsy (TLE). METHODS: Sixty-two patients with medically refractory TLE who underwent surgery were studied. Patients were categorized according to etiology (mesiotemporal sclerosis vs. tumors/cortical dysplasias); extent of surgical resection (extensive vs. limited); and amount of preoperative IED on wake EEG (oligospikers, <1 IED/h, vs. spikers). Patients were also classified as seizure-free (SF) or having persistent seizures/auras (not-SF) during follow up visits 1 month and 1 year after surgery. Preoperative 60-min interictal EEGs were evaluated for IED and ISA, and compared to postoperative wake EEGs. RESULTS: Seizures/auras persisted in 16/62 (25.8%) patients at 1 month and in 8/62 (12.9%) at 1 year follow up. ISA was not significantly related to outcome. Of 42 patients with EEG negative for IED at 1 month, 4 were not-SF; at 1 year, one of 44 such patients was not-SF. IED was significantly associated with seizure/aura persistence in patients categorized as mesiotemporal sclerosis and with extensive surgery. Oligospikers and spikers on preoperative EEG showed no differences in the postoperative seizure outcome, excellent in both cases; moreover, the presence of postoperative IEDs indicated auras/seizures persistence apart from the preoperative EEG spike frequency. CONCLUSIONS: Our study showed that the presence of IED of postoperatve EEG strongly indicates seizure/aura persistence. Therefore, serial EEGs should be included in postoperative follow up schedules as a crucial tool in evaluating seizure outcome.     

Magnetoencephalography to confirm epileptiform discharges mimicking small sharp spikes in temporal lobe epilepsy

ObjectiveTo determine whether magnetoencephalography (MEG) can identify epileptiform discharges mimicking small sharp spikes (SSSs) on scalp electroencephalography (EEG) in patients with temporal lobe epilepsy (TLE).MethodsWe retrospectively reviewed simultaneous scalp EEG and MEG recordings of 83 consecutive patients with TLE and 49 with extra-TLE (ETLE).ResultsSSSs in scalp EEG were detected in 15 (18.1%) of 83 TLE patients compared to only two (4.1%) of 49 ETLE patients (p = 0.029). Five of the 15 TLE patients had MEG spikes with concurrent SSSs in EEG, but neither of the 2 ETLE patients. Three of these 5 TLE patients had additional interictal epileptiform discharges (IEDs) in EEG and MEG. Equivalent current dipoles (ECDs) of MEG spikes with concurrent SSSs and IEDs showed no difference in temporal lobe localization and horizontal orientation, whereas ECD moments were smaller in MEG spikes with concurrent SSSs than those with IEDs.ConclusionsSSSs were more common in TLE than in ETLE. At least some morphologically diagnosed SSSs are true but low-amplitude epileptiform discharges in TLE which can be identified with simultaneous MEG.SignificanceSimultaneous MEG is useful to identify epileptiform discharges mimicking SSSs in patients with TLE.     

Limbic P3 potentials, seizure localization, and surgical pathology in temporal lobe epilepsy

Limbic P3 event-related potentials were recorded from mesial temporal electrodes implanted for presurgical investigation in 70 patients with intractable focal seizures. In 46 (81%) of 57 patients with unilateral temporal lobe epilepsy, the limbic P3 potential was absent or rudimentary ipsilateral to the seizure focus and a robust P3 potential was always elicited from the nonepileptogenic temporal lobe. Bilateral P3 potentials were recorded in 6 patients (10%) with unilateral temporal lobe epilepsy. In the remaining 5 patients in the group with unilateral temporal lobe epilepsy, results showed P3 bilaterally absent (2 patients), P3 present in a unilateral investigation (1 patient), P3 absent contralateral to the seizure focus (1 patient), and technically unsatisfactory recordings (1 patient). Bilaterally absent P3 potentials were noted in 2 patients with bilateral temporal lobe epilepsy. In 6 patients with technically adequate P3 studies and extratemporal seizures, bilaterally present P3 potentials were noted. Sensitivity and specificity of P3 absence as a predictor of an epileptogenic temporal lobe were 87% and 95%, respectively. Tissue specimens of the hippocampus were available in 22 patients (43%). Thirteen hippocampi showed sclerosis, all of which were associated with unilaterally absent P3 potentials. Nine hippocampi were normal (5 patients with the P3 absent, 4 with P3 present). Sensitivity and specificity of an absent limbic P3 as a function of hippocampal pathological findings were 100% and 44%, respectively. Absent limbic P3 potentials in temporal lobe epilepsy thus indicate structural or functional hippocampal abnormality and may add important information in presurgical evaluation with depth electrodes of patients who have temporal lobe epilepsy.     

Long-term outcome of gamma-knife surgery in temporal lobe epilepsy

PURPOSE: Indication of gamma-knife surgery (GKS) in temporal lobe epilepsy (TLE) remains a matter of debate. Either positive or negative results have been reported in studies with a maximum follow-up of 24 months. No long-term data have been published yet. METHODS: We collected data from 15 TLE patients who underwent GKS and whose follow-up was longer than 24 months. Localisation and extension of the epileptogenic zone (EZ) were assessed by SEEG in eight patients. Ten patients were presenting with mesial TLE (mTLE) while in the other five SEEG showed that the EZ was extending beyond mesio-temporal structures. GKS procedure was targeted to the EZ at a dose of 21.1+/-2.6Gy at the margin. RESULTS: The mean duration of the follow-up was 60+/-22.3 months. At last follow-up, seven patients (46.7%) were free of disabling seizure. The last seizure following GKS occurred on average after a delay of 19.75+/-20.62 months. No patient suffered recurrent seizures after a long period free of disabling seizures. No significant prognostic predictor could be individualized in this population. However, 6 of the 10 patients with mTLE (60%) were seizure free whereas only 1 of the 5 (20%) whose EZ was more extended exhibited the same seizure outcome. CONCLUSION: When a positive outcome is achieved, the risk of seizure recurrence remains low at long term. In patients with typical mTLE, long-term GKS results may be closed to those observed after conventional surgery. Conversely, this procedure should not be proposed to patients in whom SEEG results suggest that the EZ is not restricted to mesial temporal structures.     

Comparison of short-term outcome between surgical and clinical treatment in temporal lobe epilepsy: a prospective study.

OBJECTIVE: To compare the efficacy of medical and surgical treatment for refractory mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE). METHODS: A prospective controlled non-randomized study of 26 patients with MTLE who underwent surgical treatment and 75 patients with MTLE who underwent medical treatment between August 2002 and October 2004. All patients failed to achieve seizure control with at least two first line antiepileptic drugs (AED) for partial seizures before entering the study. We used Kaplan-Meier survival analyses as a function of time of seizure recurrence to obtain estimates of 95% confident interval of seizure freedom and log-rank test to compare the status of seizure control between the two groups. RESULTS: The cumulative proportion of patients free of all seizures (Engel's class IA) was higher in the surgical group (73%) compared to the clinical group (12%) (p<0.0001). In the surgical group, 2 of 26 patients (7.7%) had transient adverse effects and 2 of 26 patients (7.7%) had a permanent deficit related to the surgical procedure. In the clinical group 7 patients (9.3%) major adverse events during follow-up, including burns and status epilepticus. CONCLUSIONS: Surgical treatment for patients with MTLE who failed to achieve seizure control with two previous AED regimens was more efficient than medical treatment with further trials of AED.     

颞叶癫痫的外科治疗进展

癫痫是由多种原因导致的脑部神经元异常放电,引起机体运动?感觉?意识?行为和自主神经的不同程度障碍,其临床表现具有发作性?短暂性?重复性和刻板性的特点.颞叶癫痫(Temporal Lobe Epilepsy)是一种难治性部分癫痫,早期手术治疗疗效优于抗癫痫药物(AEDs)治疗[1-3],手术治愈率为60%~80%,有效率高达85%[4].随着现代医学影像技术的快速发展及颅内电极脑电图检测的广泛临床应用,颞叶癫痫的致痫灶定位更加精确,外科手术疗效得到广泛的认可.