Electroclinical and magnetoencephalographic analysis of epilepsy in patients with congenital bilateral perisylvian syndrome

PURPOSE: Epilepsies in four patients with congenital bilateral perisylvian syndrome (CBPS) were studied electroclinically and by magnetoencephalography (MEG) to determine whether cortical dysplasia associated with this syndrome is epileptogenic. METHODS: We studied three women and one man (mean +/- SD age 30.8 +/- 3.4 years) with a diagnosis of CBPS based on magnetic resonance imaging (MRI). All had drug-resistant epilepsy. In addition to electroclinical analysis, the distribution of equivalent-current dipoles (ECDs) analyzed from MEG signals was examined. RESULTS: Patient 1 had left-sided parietal lobe epilepsy and ECDs clustered in the left temporoparietal lobe. Patient 2 had bilateral, independent temporoparietal lobe epilepsy, and ECDs were found in both hemispheres, with clustering in the right temporoparietal lobe but not in the left hemisphere. Patient 3 presumably had parietal lobe epilepsy with unidentified focus side and ECDs clustered in the left parietal and right temporal lobes. Patient 4 had symptomatic generalized epilepsy, and ECDs were observed in both hemispheres without clustering. In the three patients who had partial epilepsy (patients 1-3), clusters of ECDs overlaid the perisylvian dysplasia and were not found elsewhere. CONCLUSIONS: Patients with CBPS may have either symptomatic partial epilepsy or symptomatic generalized epilepsy, and those with partial epilepsy are likely to have temporoparietal foci. In addition, cortical dysplasia is closely related to the generation of partial seizures and may be epileptogenic per se. However, this study did not elucidate the relationship between cortical dysplasia and CBPS-generated generalized epilepsy.     

Radiologic-pathologic correlation in focal cortical dysplasia and hemimegalencephaly in 18 children.

To describe the radiologic-pathologic correlation in children who underwent epilepsy surgery for medically intractable epilepsy with pathologically confirmed focal cortical dysplasia and hemimegalencephaly, we conducted a retrospective review on the magnetic resonance imaging and pathology of 18 children (10 boys and 8 girls). The preoperative MRIs were reviewed by one neuroradiologist who did not know the radiologic diagnosis and the pathology reports. MRI revealed focal cortical dysplasia (10), hemimegalencephaly (3), hamartomas (2), polymicrogyria (1), pial hemosiderosis (1), and no abnormality (1). Pathologic examination revealed focal cortical dysplasia (9), forme fruste of tuberous sclerosis (5), hemimegalencephaly (3), and focal cortical dysplasia with mesial temporal sclerosis (1). MRI was accurate in making the preoperative diagnosis in 16 out of 18 patients. On MRI, 12 patients had abnormal gyral formation and 12 had abnormal cortical thickness. Eleven patients manifested loss of gray-white differentiation, and 11 patients had abnormal signal on T(2)-weighted image. Pathologically, 15 patients had neuronal heterotopia, 12 had misalignment or disorientation of neurons, 11 had large neurons, and 10 had abnormal cortical lamination. The presence of ectopic and large neurons and abnormal cortical lamination may be responsible for the MRI characteristics.     

Increased expression of the neuronal glutamate transporter (EAAT3/EAAC1) in hippocampal and neocortical epilepsy

PURPOSE: To define the changes in gene and protein expression of the neuronal glutamate transporter (EAAT3/EAAC1) in a rat model of temporal lobe epilepsy as well as in human hippocampal and neocortical epilepsy. METHODS: The expression of EAAT3/EAAC1 mRNA was measured by reverse Northern blotting in single dissociated hippocampal dentate granule cells from rats with pilocarpine-induced temporal lobe epilepsy (TLE) and age-matched controls, in dentate granule cells from hippocampal surgical specimens from patients with TLE, and in dysplastic neurons microdissected from human focal cortical dysplasia specimens. Immunolabeling of rat and human hippocampi and cortical dysplasia tissue with EAAT3/EAAC1 antibodies served to corroborate the mRNA expression analysis. RESULTS: The expression of EAAT3/EAAC1 mRNA was increased by nearly threefold in dentate granule cells from rats with spontaneous seizures compared with dentate granule cells from control rats. EAAT3/EAAC1 mRNA levels also were high in human dentate granule cells from patients with TLE and were significantly elevated in dysplastic neurons in cortical dysplasia compared with non-dysplastic neurons from postmortem control tissue. No difference in expression of another glutamate transporter, EAAT2/GLT-1, was observed. Immunolabeling demonstrated that EAAT3/EAAC1 protein expression was enhanced in dentate granule cells from both rats and humans with TLE as well as in dysplastic neurons from human cortical dysplasia tissue. CONCLUSIONS: Elevations of EAAT3/EAAC1 mRNA and protein levels are present in neurons from hippocampus and neocortex in both rats and humans with epilepsy. Upregulation of EAAT3/EAAC1 in hippocampal and neocortical epilepsy may be an important modulator of extracellular glutamate concentrations and may occur as a response to recurrent seizures in these cell types.     

Nodular heterotopia: a neuropathological study of 24 patients undergoing surgery for drug-resistant epilepsy

Purpose:   Despite the availability of detailed electroclinical and imaging data, only a few neuropathological studies of nodular heterotopia have been published. The aim of this study was to describe the neuropathological features of various types of nodular heterotopia obtained from patients undergoing surgery for intractable epilepsy.
Methods: Specimens of heterotopic nodules taken from 24 patients were neuropathologically investigated using routine and immunocytochemical procedures, and the data were compared with magnetic resonance imaging (MRI), electroclinical findings, and surgical outcomes.
Results: The neuropathological data distinguished two groups. Group 1 (14 patients, 78% in Engel class 1) had similar characteristics regardless of the size, number, or location of the nodules, with both projecting and local circuit neurons in the nodules intermingled with glial cells. Thirteen patients had focal cortical dysplasia. The nodules were identified by MRI in all cases. In group 2 (10 patients, 90% in Engel class 1), all of the nodules were within the temporal lobe and associated with hippocampal sclerosis or gangliogliomas. They were very small (undetected by MRI) and mainly formed by projecting neurons with no evidence of glial cells. All of the patients had cortical dysplasia.
Discussion: The distinctive neuropathological features of the nodules in the two groups suggest different etiopathogenetic mechanisms. In group 2, the presence of nodular formations in association with cortical dysplasia and either hippocampal sclerosis or ganglioglioma raises a question concerning so-called dual pathology in the temporal lobe.     

Altered layer-specific gene expression in cortical samples from patients with temporal lobe epilepsy

Purpose: Neuropathologic investigations frequently reveal the presence of architectural cortical dysplasia in patients with temporal lobe epilepsy (TLE), sometimes as an isolated finding but more commonly associated with hippocampal sclerosis (HS) and white matter abnormalities. The histologic pattern and the developmental origin of these alterations are not clear, and their diagnostic criteria are poorly defined. The aim of this study was to investigate the expression patterns of layer‐specific genes in cortical specimens from patients with TLE presenting different subtypes of cortical malformations in order to elucidate the disorganization of the laminar architecture of such epileptogenic abnormalities and provide evidence to enable a more objective neuropathologic diagnosis. Methods: We analyzed the expression patterns of CUX2, RORBETA, ER81, NURR1, and CTGF genes, respectively specific markers of layers II–III, IV, V, VI, and VIb, in surgical samples by means of in situ hybridization and compared them with those observed in control cortices. The pathologic samples included typical architectural dysplasia (group 1); temporal lobe sclerosis, a variant of architectural dysplasia (group 2); and white matter heterotopic neuronal aggregates, namely small lentiform nodules (group 3). These abnormalities may have been associated or not with HS. Key Findings: All of the genes had a laminar expression pattern in normal cortices, whereas groups 1 and 2 showed alterations mainly involving layers V and VI, and highlighted by the altered distribution of ER81‐ and NURR1‐positive cells. The expression of ER81 and NURR1 genes was different among the groups, and atypical coexpression of NURR1 and CUX2 mRNA was detected in the neurons making up the small lentiform nodules. Significance: These findings indicate that defects in cortical organization involving the deeper cortical neurons may be a common etiopathogenic mechanism in group 1 and 2 cortical dysplasia, whether isolated or associated with HS, and that developmental disorders may also be present in the white matter (group 3). They also provide evidence that the layer‐specific genes can be usefully used to investigate the neuropathology of human cortical dysplasia.     

Inhibitory Circuits in Human Dysplastic Tissue

Summary: Purpose : Different types of epilepsies and seizures depend on the nature and location of the primary disturbance and are presumably mediated by different physiopathological mechanisms. We immunocytochemically investigated possible changes in the inhibitory -aminobutyric acid (GABA)ergic system in specimens taken from four patients who underwent surgery for intractable epilepsy and presented two different types of focal cortical dysplasia in the temporal lobe.
Methods : The patients were selected on the basis of electro-clinical, imaging, and routine neuropathological data: two had Taylor focal dysplasia, and two had non-Taylor dysplasia (microdysgenesia). The study was performed using antibodies against parvalbumin (PV), glutamic acid decarboxylase (GAD), and GABA-transporter 1 (GAT1).
Results : In the patients with Taylor dysplasia, laminar disorganization of the cortex was associated with the presence of giant neurons and ballooned cells; there was a reduced number of PV-positive neurons and terminals, the giant neurons were surrounded by clusters of PV- and GAD-positive terminals, and there was an overall reduction in GAT1. Despite the presence of cortical laminar disorganization, no giant or ballooned cells were found in the patients with non-Taylor microdysgenesia; there was a marked decrease in PV and GAD immunoreactive elements, with a patchy distribution of GAD and GAT1 immunoreactivity but no clustering of PV and GAD terminals.
Conclusions : These results suggest that the two forms of cortical dysplasia are characterized by different and selective morphofunctional alterations in the GABAergic system.     

Multicenter study of occipital lobe epilepsy in childhood: clinical characteristics

We investigated the clinical characteristics of 54 patients with childhood onset occipital lobe epilepsy (OLE). There were 25 patients of symptomatic OLE (cortical dysplasia, post encephalitis or encephalopathy, brain tumor and so on), and 29 cases of cryptogenic OLE. Eighteen patients had positive visual symptoms such as flash light, bright spots and sparks of light, 23 patients had negative ones such as scotoma, hemianopia and amaurosis and 10 patients had other complicated visual symptoms such as change of the shape or colors. Young children complained of simple visual phenomena. The youngest patient who could explain visual symptom was 3 years old. All 3 patients with visual field defects had cortical dysplasia in occipital lobe. Ictal SPECT study showed wide hyperperfusion areas in the temporo-parieto-occipital lobe in most of patients with abnormal MRI findings. CBZ and VPA were prescribed in most cases, and were effective in 65% and 60% of the patients, respectively. Seizure prognosis was relatively good. Seizures disappeared in 56% of the patients with symptomatic OLE and 79% of those with cryptogenic OLE.     

Temporo-mesial extraventricular neurocytoma and cortical dysplasia in focal temporal lobe epilepsy

We describe a 17-year-old boy with a left extraventricular temporo-mesial neurocytoma associated with cortical dysplasia causing focal pharmacoresistant temporal lobe epilepsy. He presented with a long history of medically refractory, temporal complex partial seizures. MRI showed a left temporo-mesial lesion suspect to be a low-grade tumor. Based on the pre-operative non-invasive neurophysiological studies, the patient underwent a left tailored temporal antero-mesial resection. Histopathological examination showed an extraventricular neurocytoma associated with architectural dysplasia (Type 1a) of the temporal pole. The patient was seizure-free at 2 years follow-up. Extraventricular neurocytomas must be considered in the differential diagnosis of the plethora of low-grade tumors associated with focal epilepsy that typically involve the temporal lobe, and are frequently associated with focal cortical dysplasia.     

Recurrent intractable seizures in children with cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumor

The purpose of this study was to identify the pathologic features that predict postoperative outcome in children with cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumors. We reviewed the records of children with dysembryoplastic neuroepithelial tumor who underwent epilepsy surgery and who had at least 1 year of surgical follow-up. We divided the dysembryoplastic neuroepithelial tumors into three pathology classes (simple, complex, and nonspecific), categorized adjunctive cortical dysplasia into four types, and compared histopathology with seizure outcomes. We identified 26 children with dysembryoplastic neuroepithelial tumors. Dysembryoplastic neuroepithelial tumors were complex in 19 patients (73%), simple in 6 (23%), and nonspecific in 1 (4%). Cortical dysplasia was adjacent to dysembryoplastic neuroepithelial tumors in 18 patients. Six patients had type IA cortical dysplasia, 5 had type IB, 3 had type IIA, and 1 had type IIB. The 3 remaining patients had repeated surgeries; of these, 2 patients had cortical dysplasias of type IA/IB and 1 was type IIA/IIB. Eight (39%) of 18 patients with dysembryoplastic neuroepithelial tumors and cortical dysplasia required further surgery for recurrent intractable seizures (P < .05), whereas none of 8 patients without cortical dysplasia required additional surgery. Of 13 patients with type I cortical dysplasia, only 4 had a poor seizure outcome, whereas all 5 patients with type II had a poor seizure outcome postoperatively (P < .05). Children with dysembryoplastic neuroepithelial tumor and cortical dysplasia often had recurrent intractable seizures postoperatively and required further epilepsy surgery. Cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumor can play a role in the epileptogenicity of dysembryoplastic neuroepithelial tumor. Complete resection of a dysembryoplastic neuroepithelial tumor and its adjacent cortical dysplasia should be considered.     

难治性癫痫46例患者大脑半球或多脑叶切除标本的临床病理学分析

目的 研究难治性癫痫患者大脑半球或多脑叶切除标本的临床病理学特点.方法 对2005-2009年在首都医科大学宣武医院接受大脑半球(行功能性大脑半球切除术)或多脑叶切除的46例难治性癫痫患者临床病理学资料进行回顾性分析.结果 46例患者的平均发病年龄3.9岁,平均病程为10.2年.其中行大脑半球切除33例,多脑叶切除13例,且颞叶全部受累.组织学分型:继发性瘢痕脑回31例,皮质发育畸形7例,中枢神经系统感染8例.31例瘢痕脑回标本镜下可见皮质结构消失、神经元减少、反应性胶质细胞增生及淀粉样小体出现;此外还可观察到含铁血黄素(13例)、钙化(9例)以及岛状分布的神经元(5例).瘢痕脑回均伴不同程度的皮质发育不良,并有7例伴海马硬化.7例脑回发育畸形中,局灶性皮质发育不良(FCD)5例(其中FCDⅠB型3例,FCDⅠA型1例,FCDⅡA型1例),多小脑回畸形及穿通脑畸形各1例.8例中枢神经系统感染中Rasmussen脑炎5例、巨细胞病毒性脑炎1例、结核性脑膜炎1例、囊虫感染1例.结论 大脑半球或多脑叶切除的脑组织病理学主要是多种原因(比如外伤、缺氧等)引起的继发性瘢痕脑回,颞叶病变明显.中枢神经系统感染以Rasmussen脑炎为主,皮质发育畸形主要以FCDⅠB型为主.

Abstract：

Objective To investigate the clinicopathologic features of the brain tissue from multilobar resection or hemispherectomy for refractory epilepsy. Methods The clinical and pathologic findings of 46 cases seen at Xuanwu hospital from 2005 to 2009 were reviewed retrospectively. Results The mean age of seizure onset and disease duration were 3.9 years and 10.2 years, respectively. There were 33 cases of hemispherectomy and 13 cases of multilobar resection. Temporal lobe abnormality was seen in all cases. The pathologic subgroups were as follows: ulegyria (31/46), malformation of cortical development (MCD, 7/46 ) and infection (8/46). Microscopic examination of ulegyria showed cortical architectural disturbances, neuronal loss, reactive gliosis and appearance of corpora amylacea. We also noted deposition of hemosiderin (13 cases), calcification (9 cases) and island-like neurons (5 cases). All ulegyria cases were accompanied by varying degree of cortical dysplasia, and hippocampus sclerosis were identified in 7 cases. MCD comprised of 5 cases of focal cortical dysplasia ( FCD), including 3 cases of FCDⅠB, 1 case of FCDⅡA and 1 case of FCDⅠA, 1 case of polymicrogyria and 1 case of porencephaly. Among 8 infection eases, there were 5 cases of Rasmussen encephalitis ( RE), l case of cysticercosis, 1 case of tuberculous meningitis and l case of Cytomegalovirus encephalitis. Conclusions The most common pathological category of specimens from hemispherectomy or multilobar resection is ulegyria with obvious temporal lobe abnormality. This is followed by MCD ( with FCDⅠB as the main type) and central nervous system infection (RE as the most frequent abnormality).     

Surgical treatment of epilepsy associated with cortical dysplasia: 2012 update

Cortical dysplasia is the most common etiology in children and the third most frequent finding in adults undergoing epilepsy neurosurgery. The new International League Against Epilepsy (ILAE) classification grades isolated cortical dysplasia into mild type I (cortical dyslamination), severe type II (dyslamination plus dysmorphic neurons and balloon cells), and dysplasia associated with other epileptogenic lesions (type III). Multilobar type II lesions present at an earlier age and with more severe epilepsy compared with focal type I abnormalities, often in the temporal lobe, and these findings are reflected in types and age of operations for cortical dysplasia. Presurgical evaluation of patients with epilepsy from cortical dysplasia can be challenging. Interictal and ictal scalp electroencephalography (EEG) accurately localizes cortical dysplasia with 50-66% accuracy. Structural magnetic resonance imaging (MRI) is negative in roughly 30% of cases, most often linked with mild type I cases. FDG-PET can be 80-90% accurate, but is not 100% sensitive. Chronic intracranial electrodes are used in about 50% of cases with cortical dysplasia, but often do not capture restricted ictal-onset zones. About 60% of patients with cortical dysplasia are seizure free after epilepsy neurosurgery, with much higher rates of becoming seizure free with complete (80%) compared with incomplete (20%) resections. The most common reason for incomplete resection is the risk of an unacceptable neurologic deficit. Future challenges include better tools in identifying subtle forms of type I cortical dysplasia, and development of adjunctive treatments from basic research for those undergoing incomplete resections.     

Enhanced expression of microtubule-associated protein 2 in large neurons of cortical dysplasia

To evaluate neuronal cytoarchitectural changes in cortical dysplasia, we examined microtubule-associated protein 2 (MAP2) expression in surgically resected specimens obtained from 20 patients (age range, 3 months to 10 years) treated for intractable epilepsy. Large neurons were investigated in the specimens from all patients and showed significantly strong immunoreactivity with antibodies against MAP2 in the perikaryon and proximal portion of their processes. In situ hybridization with MAP2 antitense riboprobe showed increased hybridization signal intensities in the large neurons, which correlated with the pattern of immunoreactivity for MAP2. We conclude that MAP2 is strongly expressed in the large neurons in cortical dysplasia. The results of preliminary immunoblotting in 1 patient with focal cortical dysplasia showed that the low-molecular-weight form of MAP2 (MAP2c) was strongly expressed in the dysplastic cortex, suggesting that MAP2c may be a major component contributing to the increased expression of MAP2 in the large neurons of cortical dysplasia. Since it has been suggested that MAP2 plays a crucial role in the branching and remodeling of neuronal processes, increased expression of MAP2 may reflect activated plasticity of the large neurons in cortical dyspasia.     

The spectrum of long-term epilepsy-associated tumors: long-term seizure and tumor outcome and neurosurgical aspects

PURPOSE: To describe the histologic spectrum and clinical characteristics of patients with neuroepithelial tumors and drug-resistant epilepsy and to analyze clinical data and treatment related to seizure outcome and survival. METHODS: Data were analyzed from 207 consecutive patients with intractable epilepsy (aged 2-54 years), who between 1988 and 1999 had >or=50% resection of supratentorial, neuroepithelial tumors. Extent of resection was assessed on postoperative magnetic resonance imaging (MRI); seizure outcome was classified according to Engel's outcome scale; and follow-up data were prospectively updated. RESULTS: Median follow-up was eight years (range, 2-14 years). Histologic examination revealed 154 classic epilepsy-associated tumors (ganglioglioma, dysembryoplastic neuroepithelial tumor, pleomorphic xanthoastrocytoma, and pilocytic astrocytomas) and 53 others (astrocytomas and oligodendrogliomas). Four World Health Organization (WHO) grade III tumors were found (astrocytoma, n = 3; ganglioglioma, n = 1). After surgery, 82% of the patients were seizure free (class I). The following factors were associated with improved seizure outcome: Short duration of epilepsy before surgery, single EEG focus, absence of additional hippocampal sclerosis or cortical dysplasia, transsylvian approach, other than astrocytomas, and complete tumor resection. After 5 years, only nine (4%) patients had tumor recurrence, four (2%) with malignant transformation and death. None of the four patients with anaplastic tumors died. Even patients with astrocytomas of WHO grade II or III showed 10-year recurrence of only 25% and 10-year survival of 90%. CONCLUSIONS: Tumors associated with long-term epilepsy should be removed early for two different reasons: high rate of seizure freedom and rare but potential risk of malignant tumor progression. The unexpected long survival of these astrocytomas should be investigated by using immunohistochemistry and molecular biology.     

Focal cortical malformations can show asymmetrically higher uptake on interictal fluorine-18 fluorodeoxyglucose positron emission tomography (PET)

Interictal fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a component of the presurgical evaluation of patients with medically intractable epilepsy, including patients with malformations of cortical development. The authors describe 3 cases of focal cortical malformations that displayed asymmetrically higher uptake on FDG-PET performed in the interictal state in patients undergoing evaluation for possible focal resection for refractory localization-related epilepsy. The evaluation included routine and prolonged video electroencephalography (EEG), magnetic resonance imaging (MRI), interictal FDG-PET with concurrent EEG, and single-photon emission computed tomography (SPECT). All 3 patients had focal cortical malformations on MRI corresponding to regions of asymmetrically higher uptake on FDG-PET. EEG confirmed that the FDG-PET studies were performed in the interictal state. The lesions included a large region of subcortical heterotopia in the right frontal lobe, a left temporal lobe dysplasia, and a region of subcortical heterotopia in the right occipital lobe. In both patients with subcortical heterotopia, there were other focal regions of cortical malformation that were not associated with abnormal or asymmetric uptake on FDG-PET. Previous reports describe decreased uptake on interictal PET in most cases of focal cortical malformations. Normal to increased uptake has been reported with band heterotopia. The authors demonstrate that other types of focal malformations of cortical development, including focal subcortical heterotopia and lobar dysplasia, can be associated with asymmetrically higher uptake on interictal FDG-PET.     

Temporal lobe microdysgenesis in epilepsy versus control brains

Histopathologic evaluation of brain tissue derived from surgically treated patients with medically refractory temporal lobe epilepsy (TLE) frequently reveals structural brain lesions in the surgical specimen. While several of the most commonly encountered lesions such as low-grade neoplasms or vascular malformations are well established as structural substrates of epilepsy, the significance of subtle microscopic characteristics has remained controversial. Within the spectrum a broad range of microscopic features has previously been reported as "mild cortical dysplasia," "focal cortical dysplasia," or "microdysgenesis," including cortical laminar disorganization, columnar arrangement of cortical neurons, marked clustering of neurons throughout cortical layers II-VI, increased numbers of molecular layer neurons, marked perivascular clustering of oligodendroglia in the white matter, single heterotopic neurons in the deep white matter, glioneuronal hamartia, giant neurons, and balloon cell change. In this paper we report the frequency of these features in temporal lobe tissue of 47 surgically treated TLE-patients vs 29 normal autopsy controls. While most of them were found in both cases and controls, clustering of neurons throughout cortical layers II-VI, perivascular clustering of oligodendroglia in the white matter, increased single heterotopic white matter neurons, and glioneuronal hamartias predominated in tissue from patients with epilepsy (p < 0.05). A count of more than 10 white matter neurons/HPF was associated with a worse postoperative outcome (p < 0.05). These data suggest that certain microscopic characteristics are associated with the epileptic process, while others appear as normal variants.     

Densities of parvalbumin-immunoreactive neurons in non-malformed hippocampal sclerosis-temporal neocortex and in cortical dysplasias

The changes in density of inhibitory parvalbumin-immunoreactive interneurons were quantitatively studied by immunohistochemistry in a series of human neocortical samples comprising the spectrum of malformations of cortical development (MCD) encountered in epilepsy surgery and the non-malformed hippocampal sclerosis-temporal neocortex in patients with refractory temporal lobe epilepsy. The highest relative density of parvalbumin-immunoreactive cells was obtained in the control samples (n = 21). The number of parvalbumin-immunoreactive neurons was significantly decreased in non-malformed hippocampal sclerosis-temporal neocortex (n = 73, 80.5% of control values). In a proportion of the latter samples as well as in two controls we observed patchy regions of absence of parvalbumin staining. The total counts of parvalbumin-immunoreactive cells in all the categories of MCD - "mild MCD" (n = 25), focal cortical dysplasia type I (n = 19) and type II (n = 15) - were decreased representing 72.4%, 55.0% and 12.2% of control values, respectively. Significantly different parvalbumin-immunoreactive cell densities were demonstrated between the focal cortical dysplasia types IIA and IIB. In "mild MCD", we observed a more pronounced decrease of parvalbumin-immunoreactive cells in the infragranular layers. No significant differences were revealed between the temporal and extratemporal examples of analogous MCD types. This study provides evidence for reduction of inhibitory parvalbumin-immunoreactive interneurons in the epileptic neocortex affected by MCD as well as in morphologically unaffected epileptic temporal neocortex, thus representing a possible mechanism for their epileptogenicity.     

儿童和青少年颞叶癫癎的术后长期疗效观察

目的总结儿童和青少年颞叶癫癎手术后的长期疗效和生活质量。方法回顾性分析31例儿童和青少年颞叶癫癎病人的临床资料,行标准前颞叶切除术26例,扩大前颞叶切除术2例,前颞叶切除术＋软化灶切除术2例,颞后顶下致癎灶切除术1例。评估术后癫癎发作改善情况及认知、生活质量等。结果术后随访5年以上,其中癫癎发作消失、达到EngelⅠ级26例,EngelⅡ级1例,EngelⅢ级2例,EngelⅣ级2例。术后病理示：海马组织硬化13例,皮质发育异常伴胶质增生9例,皮质发育异常伴海马组织硬化6例,神经元胶质肿瘤2例,继发性瘢痕脑回形成1例。术后并发症多数可恢复。结论儿童和青少年颞叶癫癎术后长期疗效良好,生活质量提高。     

Clinical features of neocoritcal temporal lobe epilepsy

Few Studies have examined the clinical features of neocortical temporal lobe epilepsy (NTLE) in carefully selected patients. We reviewed records from 21 patients wtih NTLE, defined by intracranial electroencephal9ogram (EEG), who have been seizure free for 1 year or more following temporal lobectomy. The mean age of onset at the time of first seizure was 14 years (range, 1–41 years). Febrile seizures were reported in only 2 patients (9.5%). In contrast to prior mesial temporal lobe epilepsy (MTLE) studies, seizure-free intervals between the initial cerebral insult or first seizure and habitual seizures were uncommon. Possible or known risk factors for epilepsy were reported in 13 of 21 patients (62%). Fifteen (71%) patients reproted auras, with experiential phenomena being the most common type. Magnetic resonance imaging was normal or nospecific in 15 patients, revealed mild hippocampal atrophy in 2, tumors in 2, and resonance imaging was normal or nospecifc in 15 patients, revealed mild hippocampal atrophy in 2, tumors in 2, and heterotopic gray matter and hippocampal atrophy in 1, and cortical dysgensis in 1. Neuropsychological testing showed deficits consistent with the seizure focus in 13 patients (62%), and Wada test showed ipsilateral memory deficits in 10 (48%). The most common behavioral manifestatin was a motionless stare at ictal onset (48%). In contrast to prior studies of MTLE, only 1 NTLE patient had frequent independent, contralateral temporal lobe epileptiform spikes on scalp EEG.     

Generalized nonconvulsive status epilepticus in symptomatic partial epilepsy

A 6-year-old male with cortical dysplasia who developed secondarily generalized nonconvulsive status epilepticus is reported. He had partial epilepsy since the age of 10 months. On electroencephalography, almost continuous left frontocentral/anterior temporal spikes were observed at 3 years of age, which lasted until 6 years of age, when he developed nonconvulsive status epilepticus. Nonconvulsive status epilepticus lasted for more than 7 days. Electroencephalography during nonconvulsive status epilepticus documented almost continuous generalized polyspike-wave complexes suggestive of generalized nonconvulsive status epilepticus. On magnetic resonance imaging, abnormal gyration was observed in the left frontal lobe. Histopathologic analysis of the resected left frontal lobe revealed cortical dysplasia. The present case demonstrates that continuous focal epileptiform discharges caused by cortical dysplasia in the frontal lobe can develop into secondarily generalized nonconvulsive status epilepticus.