Absence seizures in patients with localization-related epilepsy

We studied the clinical features of 12 patients with localization-related epilepsy (LRE) associated with absence seizures (AS). AS did not appear in any patients before partial seizures (PS) were first observed. The interval between the onset of PS and AS ranged from 1 month to 7.2 years (mean 2.11 years). The duration of AS (mean 5 months) was short compared with that of PS (mean 3.8 years). Carbamazepine (CBZ) was used in seven patients at the onset of AS. It was discontinued in five but continued in the other two. AS was initially treated with valproate in ten patients. Three of them needed additional antiepileptic drugs: clonazepam in two patients and ethosuximide in one. All patients became free from AS after treatment for AS was started, whereas PS was relatively intractable. Generalized spike-and-waves were often observed before the onset of AS. The interval between the first appearance of generalized spike-and-waves and the onset of AS ranged from 1 to 53 months (mean 20 months). AS in patients with LRE will be relatively benign and transient, and will respond well to antiepileptic drugs.     

Cluster of epileptic spasms preceded by focal seizures observed in localization-related epilepsy

This study observed six cases of localization-related epilepsy (LRE) with a cluster of epileptic spasms (ES) preceded by focal seizures (FS), defined as FS-ES. Initially, the FS was observed at a mean age 13 months; subsequently FS-ES occurred at the mean age 6 years and 3 months. The average duration from FS to FS-ES was 5 years and 1 month. All cases showed plural types of seizure (more than 2), severe mental retardation, multifoci in an interictal electroencephalogram (EEG), and abnormal findings of brain magnetic resonance imaging or computed tomography. Moreover, it was noted that high-voltage spikes were observed in the occipital area in rapid eye movements sleep on overnight EEG. According to a long-term follow-up study (average 13 years and 4 months), the 6 cases with FS-ES were divided into two types of prognosis. In 2 cases of neural cell migration disorder, the FS-ES could be detected, but in 4 cases of cerebral disorder after birth, it had disappeared. To predict a risk factor for LRE with FS-ES, six cases of FS-ES were compared with 27 cases of LRE without FS-ES. As a result of this study, there is a possibility that infants with severe brain damage may thus demonstrate frequent partial seizures and subsequently develop FS-ES.     

Correlation of criteria used for localizing epileptic foci in patients considered for surgical therapy of epilepsy

Criteria for anterior temporal lobectomy, performed on seven patients with partial complex seizures, were derived from a battery of fourteen presurgical tests. Seven tests were routine studies aimed at identifying a focus of epileptic excitability, while seven were designed to reveal areas of focal functional deficit. Conflicting information was frequently obtained from the tests of epileptic excitability, suggesting that it is probably inaccurate to view patients with partial complex seizures as having a single epileptogenic focus. Presurgical evaluation must therefore be aimed at identifying the focus most responsible for the patient's habitual seizures. Tests of focal functional deficit provided useful nonconflicting confirmatory information in each of the seven patients studied. The most reliable information was obtained from depth electrode implantation, and this procedure should be considered essential except when all evidence of surface-recorded epileptic excitability, including ictal onset, and evidence of focal functional deficit agree.     

Carbamazepine-induced involuntary movements in a girl with localization-related epilepsy]

I reported here girl with localization-related epilepsy who developed particular involuntary movements (IVMs) with a therapeutic dosis of carbamazepine. An epileptic seizure, loss of consciousness followed by a tonic-clonic seizure on the left, occurred at 9 and half years and carbamazepine was administrated. With the blood levels of 9.3 micrograms/ml (4 hours after administration), oral dyskinesia, choreiform movements of fingers of both sides, and myoclonus of the left arm developed. These IVMs disappeared soon after the decrease of the dosis (5.8 micrograms/ml, 6 hours after administration). As there was no other clinical and laboratory findings responsible for these IVMs, carbamazepine was thought to be the causative agent for them. The neurons and neural system related to the localization-related epilepsy may also have been involved.     

Magnetoencephalography in patients with tuberous sclerosis and localization-related epilepsy

PURPOSE: To clarify the usefulness of magnetoencephalography (MEG) for diagnosis of the spatial relations between spike foci and suspicious epileptogenic tubers on MRI in patients with tuberous sclerosis (TS) and to compare MEG spike foci with single-photon emission computed tomography (SPECT) findings. METHODS: We analyzed magnetic fields of epileptic spike discharges in 15 patients with TS and localization-related epilepsy (LRE) by using MEG (a whole-head 204-channel magnetometer system). We investigated the spatial relation between the equivalent current dipoles (ECDs) of interictal spike discharges and visible cortical tubers on MRI. We also compared results of MEG and MRI with SPECT findings. RESULTS: MEG detected a cluster of ECDs around one cortical tuber in six of 15 patients and clusters of ECDs around two cortical tubers in five patients. Interictal SPECT was disappointing in detection of epileptic foci in TS. However, MEG spike foci showed spatial consistency with ictal hyperperfusion areas in two patients. Three patients with single ECD clusters underwent surgical treatment: two have been seizure free, and one has obtained seizure reduction of >90%. CONCLUSIONS: ECDs were located around visible tuber nodules. MEG enabled precise localization of the epileptic foci and provided crucial information for surgical treatment in patients with TS and partial epilepsy. TS patients showing a single ECD cluster on MEG may be appropriate candidates for surgical treatment.     

癫痫中多致痫灶放射外科处理的临床研究

目的　探讨放射外科治疗顽固性癫痫中放射靶区确定的方法 ,尤其是针对多致痫灶的情况。方法　69例PET显像提示多致痫灶的病人 ,行直线加速器放射外科治疗 ,按靶区设定的不同分为两组。A组 ,2 1例 ,靶区为PET提示的致痫灶 ;B组 ,48例 ,靶区包括PET提示的致痫灶和可疑致痫灶。随访 3～ 1 6个月 ,观察两组病例在不同随访时间点的癫痫发作频率变化和治疗效果评价。结果　两组病例在三个时间点上均观察到癫痫发作频率较前明显降低 ,两组之间比较亦有显著差别 ,B组的发作频率明显低于A组。两组病例间癫痫控制疗效的比较亦有明显差异。疗效Ⅰ—Ⅱ级病人的比例 ,B组 (48.6 % )高于A组 (33 .3 % ) ;疗效Ⅴ—Ⅵ级病人的比例 ,A组 (2 2 .2 % )高于B组 (1 4 .3 % )。所有病例未见明显并发症发生。结论　PET引导放射外科治疗顽固性癫痫 ,具有较高的有效率 ,无明显并发症发生 ;PET显像所提示的全部致痫灶中有假阳性情况存在 ,但难以鉴别。在遇到此情况时 ,放射外科靶区应包括PET提示的所有病灶 ,可提高的治愈率并降低无效率     

The development of independent foci in epileptic patients

The electroencephalograms of 309 unselected epileptic patients were reexamined to ascertain the incidence of independent secondary discharges. In 41 patients (13%), a simple one-sided focus, without evidence of independent secondary discharges, was found (group 1); in 33 patients (11%), an epileptic focus with certain evidence of independent secondary discharges was found (group 2). These two groups were compared with respect to multiple variables (eg, seizure type, time course of the epileptic illness, site of foci, medication, neurological status), and significant differences between the two groups were obtained (eg, with respect to frequency of seizures, duration of seizures, number of anticonvulsive drugs being taken, and in other respects). Our findings are compared with earlier work, and it is concluded that they do not support the conventional models of secondary epileptogenesis.     

Comparative localization of epileptic foci in partial epilepsy by PCT and EEG

One or more interictal positron computed tomograms of 18F-fluorodeoxyglucose were obtained on 50 patients with partial seizure disorders. Ictal as well as interictal electroencephalographic (EEG) data were available for all 50 patients, with scalp, sphenoidal, and depth electrode recordings done on 27 and scalp and sphenoidal recordings alone on 23. Thirty-five patients demonstrated one or more abnormal interictal zones of hypometabolism, while combined EEG studies were localizing for 36. There were considerable disagreements between the location of metabolic deficits and the epileptic focus revealed by individual scalp and depth EEG recorded ictal and interictal epileptiform activity; however, there was good correlation between the site of focal hypometabolism and the epileptic focus determined by the combined results of all electrophysiological studies. When focal hypometabolism and focal nonepileptiform EEG abnormalities (i.e., slow waves and attenuation of fast rhythms) were both present in the same patient, their localization agreed completely. Metabolic and combined electrophysiological techniques both occasionally produced false positive as well as false negative results. When used together, the EEG can confirm that a hypometabolic zone is epileptogenic, while FDG scans may indicate whether an epileptic EEG focus represents a lesion or propagation from a distant site.     

Multi-center study on post-ictal headache in patients with localization-related epilepsy

The nature of post-ictal headache (PIH) remains unclear. A multicenter study was conducted in order to evaluate frequency and risk factors for PIH. The subjects consisted of 97 patients with temporal lobe epilepsy (TLE), 65 patients with frontal lobe epilepsy (FLE) and 37 patients with occipital lobe epilepsy (OLE). The subjects were asked about PIH at each institute. Clinical factors of epilepsy were reviewed for each patient and correlated with PIH. Post-ictal headache occurred in 41% of TLE patients, 40% of FLE patients and 59% of OLE patients. Logistic regression analysis revealed that the risk of PIH was significantly higher in OLE than in FLE. In contrast, there were no significant differences in the incidence of PIH between TLE and either OLE or FLE patients. Post-ictal headache occurred significantly more frequently in subjects with generalized tonic-clonic seizure (GTCS) than in those without GTCS. Other clinical factors, such as sex, age, age at onset, duration of illness, seizure frequency, family history of headache and interictal headache were found to have no associations with PIH. A difference was found in the incidence of PIH depending on classification of epilepsy, but only to a relatively slight extent. It was also found that GTCS was significantly related to PIH. These results suggest that both the location of epileptogenic focus and the involvement of certain cerebral areas in the spread of seizure discharges may be closely related to PIH.     

VEEG在难治性癫痫术前致痫灶定位中的价值

目的 探讨视频脑电图(VEEG)、单光子发射计算断层扫描(SPECT)、正电子发射断层扫描(PET)技术在术前进行致痫灶定位中的价值.方法 175例手术治疗的难治性癫痫患者,术前全部行VEEG检查,59例行VEEG +蝶骨电极记录,46例行PET致痫灶定位,61例行SPECT定位.并与术中皮层脑电图(ECoG)的结果进行比较.结果 术前VEEG定位、VEEG+蝶骨电极记录、PET检查及SPECT检查与术中ECoG致痫灶定位符合率分别为67.42%、74.57%、54.84%和52.45%.结论 VEEG在致痫灶定位中有重要的价值;对于颞叶内侧深部癫痫而言,术前以VEEG +蝶骨电极记录定位更为准确.     

Cognitive fMRI and soluble telencephalin assessment in patients with localization-related epilepsy

Objectives - The use of telencephalin as a possible marker for altered cortical function as demonstrated by functional MRI was investigated in a pilot study with 16 patients with localization-related epilepsy and secondarily generalized seizures. Materials and methods - Functional MRI of verbal working memory performance (Sternberg paradigm) and self-regulatory control processes (Stroop paradigm) was used to examine cortical activation in 16 patients with localization-related epilepsy and secondarily generalized seizures. Additionally, blood serum concentrations of soluble telencephalin (marker for neuronal damage) were determined. Results - In three patients (one temporal and two frontal focus), telencephalin was detected. All three patients had lower functional MRI activation in the frontotemporal region (P = 0.04), but not in other regions (P > 0.35) compared with patients without detectable telencephalin. Additionally, an association of levetiracetam and frontotemporal activation was observed. Conclusions - These preliminary data in a heterogeneous group suggest an association between decreased frontotemporal activation on fMRI and both detectable telencephalin serum levels and levetiracetam use. Future longitudinal studies with larger patient groups are required to confirm these observations. It is hypothesized that altered local function of the frontotemporal cortex in localization-related epilepsy might be better predicted by the biochemical marker telencephalin than epilepsy characteristics such as seizure focus.     

Lateralization of epileptic foci by magnetic resonance imaging in temporal lobe epilepsy.

A retrospective single-blind study was carried out to assess the reliability of magnetic resonance imaging (MRI) for determining lateralization of the electrographic focus in 45 patients with intractable temporal lobe epilepsy. With strictly defined MRI diagnostic criteria, the electroencephalographic (EEG) focus was correctly lateralized in 86% of patients. Excluding patients with structural lesions, the criteria provided for correct lateralization of the epileptogenic focus in 78% and false lateralization in 5%. Hippocampal atrophy on T1-weighted images and increased signal intensity from mesial structures on T2-weighted scans were highly reliable for lateralization. Postoperative outcome did not differ between the patients with normal and those with abnormal findings on MRI, but the group sample was inadequate to assess the issue of surgical outcome. These findings suggest that with appropriate techniques and strictly defined diagnostic criteria, MRI can provide reliable seizure lateralization in patients with intractable temporal lobe epilepsy.     

Spike voltage topography identifies two types of frontotemporal epileptic foci

We characterized voltage topography of frontotemporal EEG spikes in 24 patients with complex partial seizures and identified two distinct patterns. "Type 1" spikes possessed a "dipolar" field with a negative region over the inferolateral temporal scalp and a positive region over the contralateral, centroparietal scalp. "Type 2" spikes showed only a broad, frontotemporal negative field. One or the other spike type predominated in all but two patients. Correlations with clinical data and intracranial EEG suggest that type 2 spikes arise from temporal or frontal neocortex, while type 1 spikes involve mesial temporal structures as well as lateral cortex.     

Use of topiramate in localization-related epilepsy in children

Topiramate has been shown to be safe and effective in refractory partial epilepsy in children. Pharmacokinetic studies show that the clearance of topiramate is greater in children than in adults; therefore, higher doses may be needed in children than adults. It is generally well tolerated, except for cognitive dysfunction. Weight loss and the risk of renal stones can be significant in some cases. However, when compared with other anticonvulsant medications, topiramate has few serious idiosyncratic reactions such as rash, hematologic reactions, and hepatotoxicity.     

Mutually suppressive interrelations of symmetric epileptic foci in bitemporal epilepsy and their inhibitory stimulation

OBJECTIVES: The goal of this study is to analyze the suppressive interaction of symmetric temporal lobe epileptic foci, assess some failures of epilepsy surgery, and evaluate the possibility of terminating focal seizures with stimulation of symmetric epileptic foci. MATERIALS AND METHODS: One hundred and twenty-nine intractable epilepsy patients (age range 6-53 years) with bitemporal epileptiform abnormalities in multiple scalp EEGs were evaluated with chronically implanted depth and subdural electrodes. Interelectrode coherence and power spectra were studied using internally developed software. RESULTS: Bitemporal epileptic foci were found in 85/129 (66%) patients with reciprocal relations between these foci in 57/85 (67%) patients. Temporal lobectomy was performed for 67/85 patients. 12/67 patients became free of seizures (Engel's Class I), 32/67 improved (Classes II and III), and 23/67 did not improve. 14/23 patients demonstrated post-surgical activation of the contralateral temporal lobe epileptic focus. For 8/14 of these patients, the stereotactic cryoamygdalatomy was performed in the temporal lobe contralateral to the first surgery. 5/8 patients became free of seizures. It was found that stimulation of temporal lobe deep epileptic focus may terminate focal seizures in the contralateral symmetric structures. CONCLUSION: A mutually suppressive relationship is one of variants of the interaction of symmetric epileptic foci. Some epilepsy surgery failures may be a result of post-surgical activation of the intact focus. The increase of coherence between both temporal lobes before the seizure onset of the seizure suggests the establishment of functional interrelations between two epileptic foci at an early, "hidden" phase of seizures, and may predict the direction of seizure spread. Mutually suppressive interrelations of symmetric epileptic foci might be employed for chronic therapeutic stimulation.     

癫痫灶的超微结构观察及与癫痫发生机制的关系探讨

目的 观察癫痫患者痫灶的超微结构变化，以探讨癫痫的发生机制。方法 对12例顽固性癫痫患者进行皮质电图监测下手术切除痫灶，电镜下观察痫灶皮质。结果 痫灶有明显的病理变化，包括神经细胞数量减少、神经细胞水肿变性、核浓缩、异染色质边集，线粒体水肿、崩解、嵴排列紊乱，神经突触水肿，小血管或毛细血管扭曲、堵塞或内皮细胞水肿，基底膜增厚或分层，星形胶质细胞突起水肿。结论癫痫的发生均有一定的病理形态学基础，除了神经细胞、突触、星形胶质细胞的变化外，血脑屏障的改变与癫痫的发生及预后天系密切。     

The significance of ear plugging in localization-related epilepsy

PURPOSE: The localizing value of ear plugging in the treatment of auditory onset partial seizures, to our knowledge, has not been previously described. We propose that ear plugging is a clinical response to a sensory seizure manifested as an auditory hallucination and a tool for identifying the seizure focus in the auditory cortex on the superior temporal gyrus. METHODS: We report on three children who had prior epilepsy surgery for recurrent symptomatic localization-related epilepsy and who, subsequent to their surgery, displayed stereotyped unilateral or bilateral ear plugging at the onset of partial seizures. We studied scalp video electroencephalography (VEEG), magnetoencephalography (MEG), and magnetic resonance imaging (MRI) in all three. Additionally, we used electrocorticography (ECoG) in two patients, intracranial VEEG monitoring in one patient, and functional MRI language mapping in two patients. RESULTS: All three patients plugged their ears with their hands during auditory auras that localized to the superior temporal gyrus and were followed by partial seizures that spread to a wider field, as shown on scalp and intracranial VEEG. All three patients had MEG interictal discharges in the superior temporal gyrus. One patient who was nonverbal and unable to describe an auditory phenomenon plugged the ear contralateral to where temporal lobe-onset seizures and MEG interictal discharges occurred. CONCLUSIONS; Ear-plugging seizures indicate an auditory aura and may also lateralize seizure onset to the contralateral temporal lobe auditory cortex. Stereotyped behaviors accompanied by epileptic seizures in children who have poor communication skills are important in the seizure semiology of localization-related epilepsy.     

胚胎发育不良性神经上皮肿瘤的致痫灶处理

目的 探讨胚胎发育不良性神经上皮肿瘤(DNT)伴药物难治性癫痫患者的外科手术治疗方法.方法 回顾性分析了第三军医大学新桥医院神经外科采用外科手术治疗14例此类患者的经验.术前和术中均进行致痫灶定位,术中在切除肿瘤的同时一并处理肿瘤外致痫灶.结果 14例患者肿瘤均得到全切,未行放疗和化疗,无肿瘤复发及恶性转化.11例患者癫痫发作得到完全控制(Engel Ⅰ级),2例患者稀少发作(Engel Ⅱ级),1例患者术后仍有频繁癫痫发作,再次手术切除肿瘤周围致痫灶后癫痫得到完全控制.结论 DNT应当按照皮质发育障碍来处理,除切除肿瘤外,积极处理肿瘤外致痫灶可获得较佳的癫痫控制结果.