Occipital Epilepsy Research Articles

Epilepsy Surgery Series: A Study of 502 Consecutive Patients from a Developing Country

Purpose. To review the postoperative seizure outcomes of patients that underwent surgery for epilepsy at King Faisal Specialist Hospital & Research Centre (KFSHRC). Methods. A descriptive retrospective study for 502 patients operated on for medically intractable epilepsy between 1998 and 2012. The surgical outcome was measured using the ILAE criteria. Results. The epilepsy surgery outcome for temporal lobe epilepsy surgery (ILAE classes 1, 2, and 3) at 12, 36, and 60 months is 79.6%, 74.2%, and 67%, respectively. The favorable 12- and 36-month outcomes for frontal lobe epilepsy surgery are 62% and 52%, respectively. For both parietal and occipital epilepsy lobe surgeries the 12- and 36-month outcomes are 67%. For multilobar epilepsy surgery, the 12- and 36-month outcomes are 65% and 50%, respectively. The 12- and 36-month outcomes for functional hemispherectomy epilepsy surgery are 64.2% and 63%, respectively. According to histopathology diagnosis, mesiotemporal sclerosis (MTS) and benign CNS tumors had the best favorable outcome after surgery at 1 year (77.27% and 84.3%, resp.,) and 3 years (76% and 75%, resp.,). The least favorable seizure-free outcome after 3 years occurred in cases with dual pathology (66.6%). Thirty-four epilepsy patients with normal magnetic resonance imaging (MRI) brain scans were surgically treated. The first- and third-year epilepsy surgery outcome of 17 temporal lobe surgeries were (53%) and (47%) seizure-free, respectively. The first- and third-year epilepsy surgery outcomes of 15 extratemporal epilepsy surgeries were (47%) and (33%) seizure-free. Conclusion. The best outcomes are achieved with temporal epilepsy surgery, mesial temporal sclerosis, and benign CNS tumor. The worst outcomes are from multilobar surgery, dual pathology, and normal MRI.

Benign occipital epilepsy of childhood: panayiotopoulos syndrome in a 3 year old child

Panayiotopoulos syndrome (PS) is a relatively frequent and benign epileptic syndrome seen in children in the age group of 3-6 years and is characterised by predominantly autonomic symptoms and/or simple motor focal seizures followed or not by impairment of consciousness. Although multifocal spikes with high amplitude sharp-slow wave complexes at various locations can be present in the EEG, interictal electroencephalogram (EEG) in children with this particular type of epilepsy characteristically shows occipital spikes. This syndrome has known to be a masquerader and can imitate gastroenteritis, encephalitis, syncope, migraine, sleep disorders or metabolic diseases. In the absence of thorough knowledge of types of benign epilepsy syndromes and their various clinical presentations, epilepsy such as PS can be easily missed. The peculiar aspects of this type of epilepsy in children should be known not only by paediatricians but also by general doctors because a correct diagnosis would avoid aggressive interventions and concerns on account of its benign outcome. In this case study, we report a case of PS in a 3 year old child.

Characterization of seizure‐induced syncopes:EEG,ECG, and clinical features

Ictal bradycardia and ictal asystole (IA) are rare but severe complications of epileptic seizures. They are difficult to recognize within a seizure and their consequences remain unclear. Herein we aimed to extend the description of electrical and clinical features of seizures with IA and/or syncope. Among 828 patients with epilepsy who were admitted for presurgical video-electroencephalogram (EEG) monitoring evaluation between 2003 and 2012, we selected those presenting IA and/or syncope. We studied the electroclinical sequence of these manifestations and their correlation with electrocardiogram (ECG), and we compared seizures with or without IA among the same patients. Nine (1.08%) of 828 patients (four men, mean age 43 ± 6 years) showed IA. Six patients had temporal lobe epilepsy and the others had frontal, temporooccipital, or occipital epilepsy, demonstrated by intracranial EEG in two. In these patients, 59 of 103 recorded seizures induced a reduction of heart rate (HR), leading to IA in 26. IAs were mostly (80%) symptomatic, whereas ictal HR decreases alone were not. In seizures with IA, we identified usual ictal symptoms, and then symptoms related primarily to cerebral hypoperfusion (pallor, atonia, early myoclonic jerks, loss of consciousness, hypertonia, and fall) and secondarily to cerebral reperfusion (skin flushing, late myoclonic jerks). At 32 ± 18 s after the onset of the seizure, the HR decreased progressively during 11 ± 6 s, reaching a sinusal pause for 13 ± 7 s. The duration of the IA was strongly correlated with electroclinical consequences. IA was longer in patients with atonia (14.8 ± 7 vs. 5.7 ± 3 s), late myoclonic jerks (15.8 ± 7 vs. 8 ± 6 s), hypertonia (19 ± 4.5 vs. 8.3 ± 5 s), and EEG hypoperfusion changes (16 ± 5.6 vs. 6.9 ± 5.5 s). IA may induce a fall during atonia or hypertonia. Surface and intracerebral EEG recordings showed that ictal HR decrease and IA often occurred when seizure activity became bilateral. Finally, we identified one patient with ictal syncopes but without IA, presumably related to vasoplegia. We provide a more complete description of the electroclinical features of seizures with IA, of the mechanism of falls, and distinguish between hypoperfusion and reperfusion symptoms of syncope. Identification of the mechanisms of syncope may improve management of patients with epilepsy. A pacemaker can be proposed, when parasympathetic activation provokes a negative chronotropic effect that leads to asystole. It is less likely to be useful when vasoplegic effects predominate.

MEG and EEG Sensitivity in a Case of Medial Occipital Epilepsy

Interictal or ictal events in partial epilepsies may project on scalp EEG contralaterally to the side of the epileptogenic lesion. Such paradoxical lateralization can be observed in case of para-sagittal generators, and is likely due to the spatial orientation of the generator, presenting an oblique projection towards the midline. We present here a case of medial occipital epilepsy investigated using EEG, MEG and stereoelectroencephalography (SEEG). MRI displayed a focal cortical dysplasia in the superior margin of the right calcarine fissure. SEEG demonstrated bilateral medial occipital interictal spikes, with an inversion of polarity at the level of the lesion and a contralateral propagation occurring in 10ms. Interictal iterative EEG cartographies showed a large posterior field, with a maximum contralateral to the initial generator (EEG paradoxical lateralization). With the same number of channels, interictal iterative MEG cartographies were more precise and more complex than EEG ones, indicating an onset accurately lateralized. A few milliseconds later, MEG cartographies were quadripolar, thus indicating two homotopic active generators. These MEG and EEG cartographies have been reproduced using BESA dipole simulator. Relative merits of MEG and EEG are still debated. With 151 channels, MEG source localizations indicated the right medial occipital area, as demonstrated by SEEG. An investigation with a corresponding number of EEG channels was not performed. After a down sampling to 64 sensors, this precision was lost. MEG and EEG source localization results, both with 64 channels, were quite comparable, indicating both medial occipital areas. However, a careful analysis of MEG/EEG iterative cartographies, performed with the same number of channels in both modalities, demonstrated that, in this configuration, MEG sensitivity was superior to the EEG one, allowing separating two medial occipital sources, characterized in SEEG by a time delay of 10ms.

The Characterization of Childhood Occipital Epilepsy of Gastaut: A Study of Seven Patients

Characterization of the electroclinical features and evolution of childhood occipital epilepsy of Gastaut (COE-G). Seven children were retrospectively identified as having COE-G and were followed-up clinically using EEGs. Visual manifestations were the most common ictal event. Eye-associated ictal deviation was associated with ipsilateral turning of the head and migraine-like symptoms were frequent. Hemiconvulsions occurred in two children, and only one child had secondary generalized tonic-clonic seizures. In all patients, seizures occurred while awake, while two patients also had seizures while sleeping. EEG showed five patients with occipital spike-wave discharges when their eyes were closed which disappeared once their eyes were opened. Two cases continued having frequent seizures despite antiepileptic drug treatment. These patients also displayed learning difficulties and behavioral impairments after seizure onset. COE-G is a distinctive epileptic syndrome; however, the long-term prognosis for patients with the condition is unclear.

Genetics of epilepsy syndromes in families with photosensitivity

To use family studies to investigate the clinical genetics of photosensitivity to understand the interrelationship of different photosensitive epilepsy syndromes. Twenty-nine families were recruited in which at least 2 members had idiopathic epilepsy and either clinical or electrical photosensitivity on EEG studies. We performed electroclinical analysis of these individuals and all other affected family members and analyzed the phenotypic patterns in families. An earlier age at seizure onset was observed in photosensitive patients compared with nonphotosensitive individuals. A significant female bias for photosensitivity was confirmed. All subjects with visual seizures were photosensitive. Subjects could be classified into 3 main photosensitive phenotypes: genetic (idiopathic) generalized epilepsies (GGE), idiopathic photosensitive occipital epilepsy (IPOE), and mixed GGE/IPOE. Within each category, subjects with purely photosensitive seizures were observed. We report a distinctive syndrome of early-onset photosensitive absence epilepsy, with onset beginning by 4 years of age, which was more refractory than childhood absence epilepsy. The clinical genetics of the idiopathic photosensitive epilepsies show a phenotypic spectrum from the GGEs to IPOE with overlap between the focal features of IPOE and all the GGE syndromes. Shared genetic determinants are likely to contribute to the complex inheritance pattern of photosensitivity, IPOE, and the GGEs.

Gastaut type idiopathic childhood occipital epilepsy

Gastaut type idiopathic childhood occipital epilepsy is an uncommon epileptic syndrome characterised by frequent seizures, most commonly presenting as elementary visual hallucinations or blindness. Other occipital (non-visual) symptoms may also occur. Interictal EEG typically shows occipital paroxysms, often with fixation-off sensitivity. Ictal EEG is usually characterised by interruption by paroxysms and sudden appearance of low-voltage, occipital, fast rhythm and/or spikes. Despite well described clinical and EEG patterns, to our knowledge, there are very few reports in the literature with video-EEG recording of either seizure semiology or fixation-off phenomena. We present a video-EEG recording of a 12-year-old girl with Gastaut type epilepsy, illustrating the interictal and ictal aspects of this syndrome. Our aim was to demonstrate the clinical and neurophysiological pattern of a typical seizure of Gastaut type epilepsy, as well as the fixation-off phenomena, in order to further clarify the typical presentation of this syndrome. [Published with video sequences].

Divergent effects of the T1174S SCN1A mutation associated with seizures and hemiplegic migraine

To report the identification of the T1174S SCN1A (NaV 1.1) mutation in a three-generation family with both epileptic and familial hemiplegic migraine (FHM) phenotypes and clarify the pathomechanism. The five affected individuals underwent detailed clinical analyses. Mutation analyses was performed by direct sequencing of SCN1A; functional studies by expression in tsA-201 cells. A computational model was used to compare the effects of T1174S with those of a typical FHM mutation (Q1489K). The proband had benign occipital epilepsy (BOE); two relatives had simple febrile seizures (FS) and later developed BOE. Two additional relatives had FHM without epilepsy or FS. All affected members and one obliged carrier carried the T1174S mutation. Functional effects were divergent: positive shift of the activation curve and deceleration of recovery from fast inactivation, consistent with loss of function, and increase of persistent current (I(NaP)), consistent with gain of function. The I(NaP) increase was inhibited by dialysis of the cytoplasm, consistent with a modulation. Therefore, as shown by the computational model, T1174S could in some conditions induce overall loss of function, and in others gain of function; Q1489K induced gain of function in all the conditions. Modulation of the properties of T1174S can lead to a switch between overall gain and loss of function, consistent with a switch between promigraine end epileptogenic effect and, thus, with coexistence of epileptic and FHM phenotypes in the same family. These findings may help to shed light on the complex genotype-phenotype relationship of SCN1A mutations.

Siblings with refractory occipital epilepsy showing localized network activity on EEG‐fMRI

The benign occipital epilepsies of childhood include Panayiotopoulos and Gastaut syndromes; a third syndrome, idiopathic photosensitive occipital epilepsy may also begin in childhood or adolescence. We describe siblings with occipital epilepsy characterized by refractory, frequent, brief visual seizures and normal magnetic resonance imaging (MRI). Electroencephalography (EEG) with functional MRI (fMRI) supports localization of interictal epileptiform activity to the occipital lobes. Our hypothesis is that the siblings share a genetic focal epilepsy arising from a localized occipital network. Although they share many features of Gastaut syndrome, their refractory ongoing seizures in adolescence is unusual and likely due to underlying genetic determinants.

Benign occipital lobe seizures: Natural progression and atypical evolution

Benign occipital seizure syndromes are benign childhood epilepsy syndromes and are mainly of two types, Panayiotopoulos syndrome, an autonomic epilepsy and idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) including the idiopathic photosensitive occipital lobe epilepsy. Although both these types are categorized as occipital seizures, they are distinct in presentation and management. They can also be tricky to diagnose as visual symptoms may not always be the presenting feature and it is also not very easy to elicit visual hallucinations during history taking. These seizures have a good response to treatment; however, there could be atypical evolution and refractoriness to treatment especially with ICOE-G. We describe three children who presented with visual and non-visual symptoms and the electroencephalography (EEG) in all the three cases showed occipital paroxysms. We have emphasized the clues in the clinical history and EEG leading to the diagnosis of these distinct epilepsy syndromes. We have also discussed the natural course of these epilepsy syndromes with some atypical evolution, which clinicians need to be aware of during treatment of these children.

1498 Occipital Lobe Epilepsy in Kuwaiti Children: A Study Over 2 Years

ObjectiveTo study the clinical profile and therapeutic outcome of occipital lobe epilepsy in Kuwaiti children attending epilepsy clinic in a regional hospital.DesignA retrospective case series study over two years.SettingAnalysis of...

Pediatric Focal Epilepsy Syndromes

Benign epilepsy with centrotemporal spikes, early-onset childhood occipital epilepsy (Panayiotopoulos syndrome [PS]) and late-onset childhood occipital epilepsy (Gastaut type [LOCE-G]) are the principal pediatric focal epilepsy syndromes. They share major common characteristics: the appearance and resolution of electroclinical features are age related, there is a strong genetic predisposition, the clinical course is often mild with infrequent and easy to control seizures, interictal epileptiform activity is disproportionately abundant when compared with the clinical correlate, and tends to potentiate and generalize during sleep. In this review, we outline the relevant pathophysiology underlying this electroclinical spectrum. Then, the initial description of individual syndromes is followed by a summary of overlapping features and intermediate presentations that question the boundaries between these entities and provide the basis for the concept of a childhood seizure susceptibility syndrome. Additionally, we outline the main features of the related epileptic encephalopathies. An outlook on potential future lines of research completes this review.

Suppressors of interictal discharges in idiopathic childhood occipital epilepsy of Gastaut

Idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) is a rare form of epilepsy, characterized by visual hallucinations, periods of blindness, motor seizures, and migraine‐like symptoms. A characteristic EEG feature is fixation-off sensitivity: epileptiform discharges are suppressed by visual input. Here, we present an 11-year‐old girl suffering from ICOE-G, who was studied to identify potential additional suppressors of the epileptiform discharges.

Benign childhood focal epilepsies

The idiopathic focal epilepsies comprise a group of syndromes characterized by focal-onset seizures for which there is no detectable structural brain abnormality and for which there is a proposed functional mechanism for the epilepsy and electroencephalography (EEG) abnormalities. This group includes benign rolandic epilepsy (BRE), benign epilepsy with occipital paroxysms (both early onset and late-onset types), idiopathic photosensitive occipital lobe epilepsy, and some less well-defined syndromes. The limits of the early onset idiopathic occipital epilepsy syndrome are not clear, and perhaps this entity represents part of a larger syndrome group of "autonomic" age-related epilepsies. The term "idiopathic" implies absence of a structural brain lesion and a genetic propensity to seizures. The term "benign" implies that the epileptic seizures are easily treated or require no treatment, show remission without sequelae with ultimate and definitive remission before adulthood, do not have severe or exceedingly disturbing seizures, and have no associated serious intellectual or behavioral disturbances. It may be that a syndrome is benign only when it can be recognized early with reasonable certainty, thereby avoiding unnecessary investigations, overtreatment, and lifestyle restrictions. Although BRE has such characteristic clinical and EEG features to make early recognition possible, this is less constantly so in the other focal idiopathic epilepsy syndromes, where the term "benign" may be inappropriate. Mild and selective neuropsychological impairment may occur even in those with typical syndromes but it is unclear whether such selective deficits outlast the active phase of epilepsy. Sometimes the clinical course may be complicated by obvious cognitive and language impairments. In such cases, the term benign is obviously inappropriate, even when seizures are rare. In most patients with the typical focal idiopathic epilepsy syndromes, medication is not necessary.

Impaired object identification in idiopathic childhood occipital epilepsy

To investigate whether children with epilepsy primarily affecting the occipital cortex exhibit impairment of visual object identification and to what extent such a hypothesized dysfunction is related to an interfering functional, rather than structural, process. We studied nine children with idiopathic childhood occipital epilepsy (ICOE) and compared them to eight children with lesional posterior cortex epilepsy (PCEs) and to 60 age-matched controls. We applied an "ascendent" paradigm of object identification, using a coarse-to-fine order procedure, which gradually integrated spatial frequency information from the most blurred image to the complete figure. In children with ICOE, we explored how epilepsy-related variables might be related to object identification task. Children with ICOE and those with PCEs needed more physical information than controls to identify visual stimuli. There was a decreasing accuracy from controls to children with ICOE and from children with ICOE to those with PCEs. Children with ICOE demonstrated slight selective impairment in visuospatial processing and those among them having experienced a higher number of seizures or in whom interictal electroencephalography (EEG) discharges had been present for a longer time, required a higher level of physical information to recognize objects. The observation that children with ICOE performed worse than controls in object identification, although better than children with PCEs, might indicate that functional disruption caused by epileptiform EEG abnormalities and seizures, can interfere per se with perceptual processes, even in the absence of a lesion. This effect appears to be detected only by perceptual and cognitive screening.

Neurocognitive evaluation in children with occipital lobe epilepsy

PurposeThis study aimed to explore cognitive functions in patients with childhood epilepsy with occipital paroxysms (CEOP) and to compare the performance of these patients with that of patients with symptomatic occipital epilepsy (SOE) and healthy control subjects. MethodTwenty-eight patients with epilepsy (17 CEOP, 11 SOE) were enrolled. The control group had similar demographical characteristics. Cognitive functions evaluated with Wechsler Intelligence Scale for Children-revised edition (WISC-R), The Visual Aural Digit Span (VADS) and Bender Visual Motor Gestalt Test (BVMG). ResultsThe WISC-R showed lower performance IQ with WISC-R in patients with occipital epilepsy than in healthy controls. The VADS test only showed lower scores in children with symptomatic occipital epilepsy. Mean BVMG test scores were significantly abnormal in both subgroups of childhood epilepsy with occipital paroxysms (early-onset CEOP/late-onset CEOP) and the group with SOE. ConclusionPatients with CEOP, especially the late-onset form, have significant problems in the domains of visuomotor coordination, memory and attention. The academic performance of these patients should be monitored carefully in follow-up and appropriate educational support should be given as necessary.

Intra-cerebral electrical stimulation of a face-sensitive cortical area causes transient specific impairment in face recognition

Event Abstract Back to Event Intra-cerebral electrical stimulation of a face-sensitive cortical area causes transient specific impairment in face recognition Jacques Jonas1* 1 Université de Lorraine, France We report the first case of transient impairment in face recognition (prosopagnosia) induced by intra-cerebral electrical stimulation. The patient was a 32-year-old right-handed woman (KV) who has medically intractable right occipital epilepsy. She never complained of difficulties in face recognition and present with normal face recognition abilities. Intra-cerebral electrodes were implanted stereotactically to record seizures and to perform focal electrical stimulation in order to define epileptogenic and functional zones. During stimulations of right and left occipito-temporal contacts (biphasic pulse; 50 Hz train of 5 s; from 1 to 1.8 mA), she was asked to name previously correctly recognized famous faces, objects and scenes. Six of seven bipolar stimulations including one common contact (named O7) located within the right inferior occipital gyrus reproducibly induced transient prosopagnosia which completely recovered immediately upon termination of the stimulation. The patient reported a disturbance in perceiving the spatial relationship of facial elements and being unable to perceive the face as a whole. Stimulations at this site never produced visual distortions, deficit in object and scenes recognition or epileptic discharges. Stimulations of all other contacts and electrodes did not elicit prosopagnosia. The brain region of interest was mapped using fMRI and intra-cerebral ERPs by contrasting responses to pictures of faces and objects. The eloquent stimulation site O7 was located exactly within the right occipital face area (rOFA). A N170 face-specific potential was also recorded at the stimulation site reinforcing the functional specificity of this area for face perception. We also found a N170 face-specific potential at an anterior site F6, located at the edge of the right FFA. However, its stimulation did not evoke any prosopagnosia. These findings provide evidences that the right OFA is necessary for normal face perception as part of a bilateral occipito-temporal network of face-sensitive areas. Keywords: face perception, OFA, Electrical Stimulation, Prosopagnosia, N170 Conference: Belgian Brain Council, Liège, Belgium, 27 Oct - 27 Oct, 2012. Presentation Type: Poster Presentation Topic: Higher Brain Functions in health and disease: cognition and memory Citation: Jonas J (2012). Intra-cerebral electrical stimulation of a face-sensitive cortical area causes transient specific impairment in face recognition. Conference Abstract: Belgian Brain Council. doi: 10.3389/conf.fnhum.2012.210.00093 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Aug 2012; Published Online: 12 Sep 2012. * Correspondence: Dr. Jacques Jonas, Université de Lorraine, Nancy, France, jac.jonas@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jacques Jonas Google Jacques Jonas Google Scholar Jacques Jonas PubMed Jacques Jonas Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Correlación de la morfometría por resonancia magnética con los hallazgos clínicos y electroencefalográficos de pacientes con diagnóstico de ulegiria y epilepsia

Ulegyria is a cortical lesion affecting neighbouring vascular zones, which gives the convolutions a mushroom-like appearance. It is an important cause of occipital epilepsy. AIM. To correlate patients diagnosed clinically, electrically and morphometrically with ulegyria and epilepsy by comparing the thickness of the cortex in the zones affected by ulegyria with the normal cortical thickness reported in the literature and the average cortical thickness of healthy subjects. Ten patients with ulegyria confirmed by magnetic resonance imaging were included in the study; all of them were submitted to a clinical interview, an electroencephalographic study and cortical morphometric analysis based on volumetric T1 sequences. Findings included a predominance in males, neurodevelopmental retardation and epilepsy. Ulegyria was mainly parietooccipital, frequently bilateral, with statistically significant thinning of the cortical thickness in the site of the lesion and an increase in the thickness of the cortex in the areas surrounding the lesion. We report on a series of patients with ulegyria with characteristics similar to those existing in the literature and by means of morphometry we detected an increase in the thickness of the cortex around the areas affected by ulegyria. These findings could point to the presence of adaptive neuroplasticity in the neurons that surround the scar tissue or they may be the result of mechanical changes of normal tissue in response to the loss of volume of the ulegyria-affected area, although these data need to be replicated in a study with a greater number of patients.

Childhood epileptic seizures imitating migraine and encephalitis

Paroxismal events can resemble epileptic seizures, however, some epileptic seizures, especially benign occipital childhood epilepsies can imitate migraine, cycling vomiting or encephalitis. The aim of this study was evaluation of clinical and electroencephalographic (EEG) features and outcome in children with benign occipital childhood epilepsies. Investigation included 18 patients with benign occipital childhood epilepsies hospitalized in the period from 2007 to 2010. The diagnosis was based on clinical and EEG characteristics of seizures, while treatment included acute therapy for seizures and chronic antiepileptic drugs. Prognosis was analyzed in terms of neurological outcome and seizure recurrence rate. Benign occipital childhood epilepsy with early onset was diagnosed in 15 children. Vegetative symptoms, mostly ictal vomiting (13), eye deviation and loss of consciousness (13) dominated in the clinical presentation. The most frequent EEG findings showed occipital epileptic discharges. Benign occipital childhood epilepsy with late onset was diagnosed in three cases. Seizures were manifested by visual hallucinations, headache and secondary generalized convulsions. All three patients were administered chronic antiepileptic drugs and had good outcome. In our patients, clinical manifestations of benign occipital epilepsies had some similarities with clinical features of migraine and encephalitis. It could explain misdiagnosis in some of them. Knowledge about main features and differences between each of these disorders is crucial for making appropriate diagnosis.

Imaging the seizure onset zone with stereo-electroencephalography

Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we revisit epileptogenicity in light of neuroimaging tools such as those provided in statistical parametric mapping software. Our goal is to propose a robust approach, allowing easy exploration of patients' brains in time and space. The procedure is based upon statistical parametric mapping, which is an established framework for comparing multi-dimensional image data that allows one to correct for inherent multiple comparisons. Statistics can also be performed at the group level, between seizures in the same patient or between patients suffering from the same type of epilepsy using normalization of brains to a common anatomic atlas. Results are obtained from three case studies (insular reflex epilepsy, cryptogenic frontal epilepsy and lesional occipital epilepsy) where tailored resection was performed, and from a group of 10 patients suffering from mesial temporal lobe epilepsy. They illustrate the basics of the technique and demonstrate its very good reproducibility and specificity. Most importantly, the proposed approach to the quantification of the seizure onset zone allows one to summarize complex signals in terms of a time-series of statistical parametric maps that can support clinical decisions. Quantitative neuroimaging of stereo-electroencephalographic features of seizures might thus help to provide better pre-surgical assessment of patients undergoing resective surgery.