Occipital lobe epilepsy: clinical characteristics, surgical outcome, and role of diagnostic modalities

PURPOSE: To assess the role of various diagnostic modalities, to identify surgical prognostic factors and concordances with presurgical evaluations, and to characterize the clinical features of occipital lobe epilepsy (OLE), we studied 26 patients who were diagnosed as having OLE and underwent epilepsy surgery. METHODS: Diagnoses were established by standard presurgical evaluations, which included magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), ictal single-photon emission computed tomography (SPECT), scalp video-EEG monitoring, and intracranial EEG monitoring. After epilepsy surgery, patients were followed up for >2 years. RESULTS: Sixteen (61.5%) of the 26 became seizure free after surgery, and another eight patients had a favorable outcome. Sixteen of the 26 patients experienced a type of visual aura (i.e., visual hallucination, visual illusion, blindness, or a field defect). Nine patients had both automotor seizures and secondary generalized tonic-clonic seizures at different times. Interictal EEG showed correctly localizing spikes in 10 of the 16 patients who became seizure free, and in three of the 10 non-seizure-free patients. MRI correctly localized the lesion in seven of these 16 seizure-free patients, and in three of the 10 non-seizure-free patients. FDG-PET correctly localized the lesion in eight of the 16 seizure-free patients, and in three of nine non-seizure-free patients. Ictal SPECT was performed in 19 patients and correctly localized the lesion in only three of 12 seizure-free patients, and in four of seven non-seizure-free patients. Ictal EEG correctly localized the lesion in 13 of the 16 seizure-free patients, and in five of the 10 non-seizure-free patients. No significant relation was found between the diagnostic accuracy of any modality and surgical outcome. The localizations of epileptogenic zones by these different diagnostic methods were complementary. The concordance of three or more modalities was significantly observed in seizure-free patients (p = 0.042). However, no definite relation was observed between the presence of lateralizing clinical seizure manifestation and surgical outcome (p = 0.108). CONCLUSIONS: Some specific auras indicated an occipital epilepsy onset. Various diagnostic methods can be useful to diagnose OLE, and a greater concordance between presurgical evaluation modalities indicates a better surgical outcome.     

Frontal lobe epilepsy.

Frontal lobe epilepsy accounts for only 10-20% of the patients in surgical series, but the incidence in non-surgical patient cohorts seems to be much higher. The typical clinical presentation of the seizures includes contralateral clonic movements, uni- or bilateral tonic motor activity as well as complex automatism. The yield of surface EEG may be limited due to the difficulty in detection of mesial or basal foci, and the patient may be misdiagnosed as having non-epileptic events. In addition, in patients with mesial frontal foci the epileptiform discharges may be mislateralized ("paradoxical lateralization"). Therefore, epilepsy surgery has been commonly considered as less promising in patients with frontal lobe epilepsy. However, the advent of sophisticated neuroimaging techniques, particularly MRI with epilepsy-specific sequences, has made it possible to delineate the epileptogenic lesion and detect a specific etiology, in an increasing number of patients. Thus, the success rate of epilepsy surgery in frontal lobe epilepsy is currently comparable to temporal lobe epilepsy, if the candidates are carefully selected. Patients with frontal lobe epilepsy who do not respond to anticonvulsive medication, and who are not eligible for epilepsy surgery may benefit from alternative approaches such as electrical brain stimulation.     

Intractable occipital lobe epilepsy: Clinical characteristics and surgical treatment

Intractable occipital lobe epilepsy remains a surgical challenge. Clinical characteristics of 14 patients were analyzed. Twelve patients had surgery, seven patients had visual auras (50%) and only eight patients (57%) had posterior scalp EEG changes. Ictal single‐proton emission computed tomography (SPECT) incorrectly localized in 7 of 10 patients. Six patients (50%) had Engel’s class I outcome. Patients with inferior occipital seizure onset appeared to fare better (three of four class I) than patients with lateral or medial occipital seizure onset (three of eight class I). Patients who had all three occipital surfaces covered with electrodes had a better outcome (four of five class I) than patients who had limited electroencephalography (EEG) coverage (two of seven class I). Magnetic resonance imaging (MRI) lesions did not guarantee a seizure free outcome. In conclusion, visual auras, scalp EEG, and imaging findings are not reliable for correct identification of occipital onset. Occipital seizure onset can be easily missed in nonlesional epilepsy. Comprehensive intracranial EEG coverage of all three occipital surfaces leads to better outcomes.     

额叶癫痫

额叶癫痫作为一种特定的癫痫类型,早已为人们所认识。近年国内外相继有关于额叶癫痫的病例报道。在临床工作实践中,额叶癫痫虽不少见,但由于额叶结构及功能的复杂性以及额叶癫痫发作形式的多样性,使其极易被漏诊或误诊。至今人们对该病认识的深度和广度仍嫌不足。本文就额叶癫痫的临床及脑电图表现加以综述。一、额叶癫痫的解剖定位及分型额叶位于大脑前部,包括中央沟以前的全部皮质区。额叶是仅次于颞叶易产生癫痫的第二脑区。目前认为造成额叶癫痫的病因以颅脑创伤、颅内肿瘤、感染、缺氧、脑动-静脉畸形以及皮质发育异常为多见。1989年国…     

Frontal lobe epilepsy

About one-quarter of patients with refractory focal epilepsies have frontal lobe epilepsy (FLE). The typical seizure semiology for FLE includes unilateral clonic, tonic asymmetric or hypermotor seizures. Interictal electroencephalograms (EEG) usually reveal interictal epileptiform discharges and rhythmical midline theta, which has localizing value. The usefulness of ictal EEG recordings is limited by frequent muscle artifacts in motor seizures and because a large portion of the frontal lobe cortex is “hidden” to scalp electrodes. Ictal single photon emission CT and positron emission tomography are able to localize FLE in about one-third of patients only. A pre-surgical evaluation should include, whenever possible, a subclassification of FLE as dorsolateral frontal, mesial frontal or basal frontal lobe epilepsy to allow a minimal cortical resection. A review of the typical findings of seizure semiology, interictal and ictal EEG regarding the different FLE subtypes is given. Etiology, medical treatment and surgery are also discussed.     

Frontal lobe tumoral epilepsy: clinical,neurophysiologic features and predictors of surgical outcome

PURPOSE: To review the clinical, neurophysiologic features and surgical outcomes in patients with frontal lobe tumors and chronic intractable seizures. METHODS: Medical records of patients with intractable epilepsy who underwent resection or stereotactic biopsy of frontal lobe tumor (confirmed by surgical pathology) seen between 1985 and 1999 at Yale University School of Medicine Epilepsy Center were reviewed for age at diagnosis, age at onset of seizures, delay between seizure onset and tumor diagnosis, types and frequencies of seizures, EEG results, use of anticonvulsants, extent of surgery, pathological diagnosis, and tumor recurrence. RESULTS: Thirty-seven patients were included. Mean age at seizure onset was 31.6 years, and at tumor diagnosis was 36.2 years. Mean duration between onset of seizures and tumor diagnosis was 6.1 years. Seventeen patients had auras. Seizure frequency averaged 7.6 seizures per week, with 58% of patients having more than one seizure type. All patients used anticonvulsants, with 90% eventually using polytherapy. All patients eventually underwent at least one surgical procedure. Only 13 (35.1%) patients were class I. Twelve (32.4%) patients were class II, seven (18.9%) class III, and five (13.5%) class IV. No statistically significant differences were seen between good and poor long-term seizure outcome in relation to specific tumor pathology, seizure types, or type of resection. CONCLUSIONS: Long-term surgical outcomes in tumoral frontal lobe epilepsy are more favorable than those in nontumoral intractable frontal lobe epilepsy (65% class I or II) and less favorable than those in other tumoral epilepsy (overall, 70% class I). Frontal location of intracranial neoplasm may predict a less favorable long-term epilepsy prognosis than tumoral epilepsy in general, an observation for which several explanations are proposed.     

枕叶癫痫外科治疗的特点与疗效(附13例报道)

目的 探讨枕叶癫痫外科治疗的特点与手术疗效.方法 回顾分析13例枕叶癫痫患者完整的临床资料,总结其发作症状学、影像学、EEG、神经病理学及手术治疗等方面的特征与手术疗效.结果 局灶性皮质发育不良为最常见病理表现(6例).术后2周时6例患者原有视觉障碍加重或新出现视觉障碍.术后随访2～5年,Engel's I级7例(53.8%),II级1例,III级2例,IV级3例.结论 定位明确的枕叶癫痫可以通过适当的手术治疗获得较满意疗效,但常常加重视觉功能障碍.     

Frontal lobe function in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is typically associated with long-term memory dysfunction. The frontal lobes support high-level cognition comprising executive skills and working memory that is vital for daily life functioning. Deficits in these functions have been increasingly reported in TLE. Evidence from both the neuropsychological and neuroimaging literature suggests both executive function and working memory are compromised in the presence of TLE. In relation to executive impairment, particular focus has been paid to set shifting as measured by the Wisconsin Card Sorting Task. Other discrete executive functions such as decision-making and theory of mind also appear vulnerable but have received little attention. With regard to working memory, the medial temporal lobe structures appear have a more critical role, but with emerging evidence of hippocampal dependent and independent processes. The relative role of underlying pathology and seizure spread is likely to have considerable bearing upon the cognitive phenotype and trajectory in TLE. The identification of the nature of frontal lobe dysfunction in TLE thus has important clinical implications for prognosis and surgical management. Longitudinal neuropsychological and neuroimaging studies assessing frontal lobe function in TLE patients pre- and postoperatively will improve our understanding further.     

Frontal lobe epilepsy in childhood

Frontal lobe epilepsy is poorly understood and often unrecognized by health care workers caring for children. We sought to better characterize frontal lobe epilepsy in childhood and help delineate this condition from other nonepileptic events. We reviewed pediatric patients admitted to the Comprehensive Epilepsy Program at the University of Alberta Hospitals with a proven diagnosis of frontal lobe epilepsy. Twenty-two patients, 13 males and 9 females, were studied. Age of onset was variable from 10 months to 16 years (mean 7.5 years). Seizures were brief (30 seconds to 2 minutes), stereotypic, nocturnal (17/21), and frequent (3-22/night). Clinical features included explosive onset, screaming, agitation, stiffening, kicking or bicycling of the legs, and incontinence. The diagnosis of frontal lobe epilepsy was not made in any child before referral. The referring diagnosis was sleep disturbance (10), psychiatric problems (6), or other seizure types (6). Interictal electroencephalogram was usually normal (18/21). Long-term video electroencephalographic monitoring demonstrated frontal (9) or bifrontal (13) epileptic discharges. Magnetic resonance imaging was normal in most patients (18/21). Seizure control was difficult, with only half (11/21) the patients being controlled on medication. Three intractable patients went on to epilepsy surgery and became seizure-free. Frontal lobe epilepsy in childhood is a distinct epilepsy syndrome with characteristic features. The seizures are brief, stereotypic, nocturnal, and frequent. Electroencephalogram and magnetic resonance imaging are usually normal. The condition is often misdiagnosed as a sleep disorder or psychiatric problem. Seizures are difficult to control but may respond to carbamazepine, valproic acid, or epilepsy surgery.     

Temporal lobe pleomorphic xanthoastrocytoma and chronic epilepsy: long-term surgical outcomes

Objective

To review clinical features and surgical outcome in patients with temporal lobe pleomorphic xanthoastrocytomas (PXAs) and intractable epilepsy.

Methods

The Rush Surgical Epilepsy Database was queried to identify patients with chronic intractable epilepsy who underwent resection of a temporal lobe PXA at Rush University Medical Center. Medical records were reviewed for demographic, procedure and follow-up data.

Results

Four patients were identified with a temporal lobe PXA and intractable epilepsy. Average age of seizure onset was 16.5 years and delay to surgery was 90 months. Complex partial seizures were the most common presenting symptom, shown in all 4 patients, and 3 of 4 patients presented with simple partial seizures as well. Seizures occurred with an average frequency of 4 per month (range 1-12 per month). Detailed operative and post-operative follow up data was available for all 4 patients. Gross total resection of the tumor was achieved in all 4 cases. Three of 4 cases had complete resection of the amygdala, and 3 cases had resections of the hippocampus (one partial and two complete). On histopathology, all tumors were found to be low-grade, without mitoses or necrosis. Average follow-up was 120 months (range 29-296 months) with all 4 patients achieving Engel's class I outcome. At last follow up, there was no radiographic or clinical evidence of tumor recurrence. There were no permanent complications.

Conclusions

Temporal lobe pleomorphic xanthoastrocytomas causing chronic intractable epilepsy occur in younger patients, and demonstrate excellent long-term results in seizure improvement and tumor control with surgery. We support the choice between simple lesionectomy and a tailored resection with amygdalohippocampectomy guided by preoperative findings, intraoperative electrocorticography, and the severity and chronicity of the patient's epilepsy.     

Parietal lobe epilepsy: the semiology, yield of diagnostic workup, and surgical outcome

PURPOSE: To characterize the clinical features, the prognostic value, and diagnostic sensitivities of various presurgical evaluations and the surgical outcomes in parietal lobe epilepsy (PLE), we describe 40 patients who were diagnosed as having PLE, including 27 surgically treated patients. METHODS: The diagnosis was established by means of a standard presurgical evaluation, including magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), ictal single-photon emission tomography (SPECT), and scalp video-electroencephalography (EEG) monitoring, with additional intracranial EEG monitoring in selected cases. RESULTS: Among the 40 patients, 27 experienced at least one type of aura. The most common auras were somatosensory (13 patients), followed by affective, vertiginous, and visual auras. The patients had diverse manifestations. Eighteen patients showed simple motor seizure, followed by automotor seizure, and dialeptic seizure. Two patients manifested generalized tonic-clonic seizures only, and 19 patients experienced more than one type of seizure. The surgical outcome was favorable in 22 of 26 patients including 14 who were seizure free. Patients with localized MRI abnormality had a higher probability to be seizure free, with marginal significance (p = 0.062), whereas other diagnostic modalities failed to predict the surgical outcome. In the seizure-free group, localization sensitivity was 64.3% by MRI, 50% by PET, 45.5% by ictal SPECT, and 35.7% by ictal EEG. The concordance rate of the various diagnostic modalities was higher in the seizure-free group than in the non-seizure-free group, although it did not reach statistical significance. CONCLUSIONS: Seizures, in the case of PLE, can manifest themselves in a wider variety of ways than was previously thought. Surgical outcome was favorable in most of the patients. MRI abnormality and concordance of different diagnostic modalities were associated with high seizure-free rate.     

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.     

Temporal lobe gangliogliomas associated with chronic epilepsy: Long-term surgical outcomes

Objective

To review the clinical features and surgical outcome in patients with temporal lobe gangliogliomas associated with intractable chronic epilepsy.

Methods

The Rush University Surgical Epilepsy Database was queried to identify patients with chronic intractable epilepsy who underwent resection of temporal lobe gangliogliomas at Rush University Medical Center. Medical records were reviewed for age of seizure onset, delay to referral for surgery, seizure frequency and characteristics, pre-operative MRI results, extent of resection, pathological diagnosis, complications, length of follow-up, and seizure improvement.

Results

Fifteen patients were identified. Average duration between seizure onset and surgery was 14.3 years. Complex partial seizures were the most common presenting symptom. Detailed operative data was available for 11 patients – of these, 90.9% underwent complete resection of the amygdala and either partial or complete resection of the hippocampus, in addition to lesionectomy. Average follow-up was 10.4 years (range 1.6–27.5 years), with 14 patients improving to Engel's class I and one patient to Engel's class III. There were no recurrences, and permanent complications were noted in one patient.

Conclusions

Long-term follow-up of patients with temporal lobe gangliogliomas associated with chronic intractable epilepsy demonstrates excellent results in seizure improvement with surgery and increasingly low incidence of complications with improvements in microsurgical techniques.     

Frontal lobe dysfunction in children with temporal lobe epilepsy

There is evidence that adults with temporal lobe epilepsy present executive impairments. However, there is limited information in children, especially when using a comprehensive neuropsychologic battery. We aimed to: 1) investigate the presence and severity of executive dysfunctions in children with temporal lobe epilepsy, and 2) determine the implications of clinical variables (including etiology) in the occurrence and severity of executive dysfunction, using eight paradigms. Thirty-one children with temporal lobe epilepsy were evaluated and compared with 21 age-matched controls. Patients with temporal lobe epilepsy had significantly worse performance than controls. Intragroup analysis indicated that patients with symptomatic epilepsy were more impaired than those with cryptogenic epilepsy. In the former group, patients with mesial lesions performed worse than those with lateral lesions. Regarding the severity of executive dysfunction, 83.87% manifested severe to moderate executive impairment. Early age of onset, longer duration of epilepsy, and use of polytherapy were correlated with worse executive dysfunction. These findings indicated the presence of frontal lobe dysfunction in children with temporal lobe epilepsy, with worse performance in those with mesial temporal lobe epilepsy, early onset, longer duration of disease, and use of polytherapy. Our study corroborates the hypothesis that temporal lobe epileptogenic activity affects the extratemporal regions that mediate attentional and executive functions.     

Frontal lobe epilepsy presented as ictal aggression

Abstract Aggressive behaviour is rarely observed as an ictal semiology. Ictal aggression can occur in lesions of frontal and limbic structures. In limbic structure lesions, the main mechanism of aggressive behaviour is hyperactivity; whereas frontal lesions may cause aggressive behaviour with an indirect mechanism in which the suppression on limbic system is lost. Here we present a patient with ictal aggression. In this case a right frontoparietal epileptiform focus was detected during the postictal period. Magnetic resonance imaging showed cortical dysplasia on the right inferior frontal gyrus. The seizures disappeared completely after pharmacological treatment.     

Frontal lobe degeneration: clinical, neuropsychological, and SPECT characteristics

The clinical, neuropsychological, and cerebral blood flow characteristics of eight patients with frontal lobe degeneration (FLD) were studied. Social withdrawal and behavioral disinhibition were the earliest and most common clinical presentations, and psychiatric symptoms typically preceded the onset of dementia by several years. Neuropsychological testing showed selective impairment of frontal and memory tasks with relative sparing of attention, language, and visuospatial skills. Single-photon emission computerized tomography demonstrated frontal and temporal hypoperfusion with relative sparing of parietal and occipital blood flow. Previous studies suggest that the neuropathologic findings in patients with FLD are varied; some demonstrate frontal gliosis, neuronal loss, and Pick bodies while others show only gliosis and neuronal loss.     

磁共振成像阴性颞叶癫痫的临床特点分析

目的探讨磁共振成像(MRI)阴性颞叶癫痫(nonlesional temporal lobe epilepsy,TLE-NL)患者的临床特征、记忆水平和影像学特点。方法纳入2012年9月1日至2017年8月31日在浙江大学医学院附属第二医院确诊的44例单侧TLE-NL患者和53例同期就诊单侧颞叶癫痫伴海马硬化(temporal lobe epilepsy with hippocampal sclerosis,TLE-HS)患者,对TLE-NL和TLE-HS的临床特点进行对比。同时纳入20名健康志愿者作为正常对照组。采用韦氏记忆量表评估患者和对照组记忆功能,并通过高分辨率MRI定量分析海马体积及形态,评估TLE-NL和TLE-HS患者记忆水平和海马体积的改变。结果TLE-NL患者比TLE-HS患者发病年龄更晚[(24.3±12.6)岁与(15.8±10.3)岁;t=3.684,P<0.01],癫痫病程更短[4.00(2.00,8.75)年与14.00(7.50,22.00)年;Z=-4.675,P<0.01],热性惊厥史比例[4.5%(2/44)与62.3%(33/53);χ2=32.270,P<0.01)和药物难治性比例更低[47.7%(21/44)与84.9%(45/53);χ2=15.282,P<0.01)。TLE-NL患者在性别比例、癫痫家族史、致痫灶侧别、先兆发生率、症状学类型及发作频率上与TLE-HS患者类似。TLE-NL患者与正常对照组相比无明显记忆损害(记忆商数:105.2±17.4与103.8±16.2;P=1.000),而TLE-HS患者与正常对照组相比存在明显记忆损害(记忆商数:84.5±20.3与103.8±16.2;P<0.01)。TLE-NL患者海马体积和形态与正常对照组相比无明显改变,而TLE-HS患者存在明显致痫灶同侧海马萎缩[(2953±481)mm3与(4431±505)mm3;P<0.01),形态分析结果提示萎缩以海马头及海马体部明显。结论TLE-NL是一类有别于TLE-HS的颞叶癫痫综合征,具有发病年龄晚、病程短、热性惊厥史少、药物难治性癫痫发生率较低、无明显记忆损害及海马萎缩的临床特点。