Search

Forecasting seizure risk aims to detect pro-ictal states in which seizures would be more likely to occur. Classical seizure prediction models are trained over long-term EEG recordings to detect specific preictal changes for each seizure, independently of those induced by shifts in states of vigilance. A daily single measure - during a vigilance-controlled period - to estimate the risk of upcoming seizure(s) would be more convenient. Here, we evaluated whether intracranial EEG connectivity (phase-locking value), estimated from daily vigilance-controlled resting-state recordings, could allow to distinguish interictal (no seizure) from preictal (seizure within the next 24hrs) states. We also assessed its relevance for daily forecasts of seizure risk using machine learning models. Connectivity in the theta band was found to provide best prediction performances (AUC≥0.7 in 80% of patients), with accurate daily and prospective probabilistic forecasts (mean Brier and skill Brier scores of 0.11 and 0.74, respectively). More efficient ambulatory clinical application could be considered using mobile EEG or chronic implanted devices.

Periventricular nodular heterotopia (PNH) is a malformation of cortical development that frequently causes drug-resistant epilepsy. The epileptogenicity of ectopic neurons in PNH as well as their role in generating interictal and ictal activity is still a matter of debate. We report the first in vivo microelectrode recording of heterotopic neurons in humans. Highly consistent interictal patterns (IPs) were identified within the nodules: (1) Periodic Discharges PLUS Fast activity (PD+F), (2) Sporadic discharges PLUS Fast activity (SD+F), and (3) epileptic spikes (ES). Neuronal firing rates were significantly modulated during all IPs, suggesting that multiple IPs were generated by the same local neuronal populations. Furthermore, firing rates closely followed IP morphologies. Among the different IPs, the SD+F pattern was found only in the three nodules that were actively involved in seizure generation but was never observed in the nodule that did not take part in ictal discharges. On the contrary, PD+F and ES were identified in all nodules. Units that were modulated during the IPs were also found to participate in seizures, increasing their firing rate at seizure onset and maintaining an elevated rate during the seizures. Together, nodules in PNH are highly epileptogenic and show several IPs that provide promising pathognomonic signatures of PNH. Furthermore, our results show that PNH nodules may well initiate seizures.

Focal neuronal lipofuscinosis (FNL) is an uncommon epileptic disorder related to an excess of lipofuscin accumulation within dysmorphic-appearing neurons (DANs), whose epileptogenic mechanisms are still poorly understood. It shares some clinical and neuroimaging similarities with focal cortical dysplasia of type IIb (FCDIIb), but it represents a different pathological entity. Here, we identified two patients with FNL among a 10-year cohort of 323 patients who underwent neurosurgery for a focal pharmacoresistant epilepsy. We describe the electroclinical, metabolic and neuropathological features of both patients with FNL who benefited from a comprehensive presurgical investigation. While the previous reports showed frontal lobe localization of the lesion, FNL was identified in the temporal lobe, in one of our patients. EEG investigations in both patients showed striking focal and rich interictal activity resembling that described in FCDIIb. Besides focal intraneuronal lipofuscin accumulation, the neuropathological analysis demonstrated that somata of DANs were surrounded by a large amount of GABAergic presynaptic buttons, suggesting the involvement of interneurons in the epileptogenicity of FNL. To further explore the role of GABAergic transmission in the generation of epileptiform activity in FNL, we performed in vitro multi-electrode array recordings on the post-surgery tissue from one patient. Spontaneous interictal-like discharges (IILDs) were identified only in the restricted area displaying the highest density of lipofuscin-containing DANs, suggesting a close correlation between the density of lipofuscin-containing neurons and epileptogenicity. Moreover, IILDs were blocked by the GABAA receptor antagonist gabazine. All together, these findings showed how GABA signaling may contribute to the generation of interictal-like activity in FNL tissue.

The stimulus-evoked neural response is a widely explored phenomenon. Conscious awareness is associated in many cases with the corresponding selective stimulus-evoked response. For example, conscious awareness of a face stimulus is associated with or accompanied by stimulus-evoked activity in the fusiform face area (FFA). In addition to the stimulus-evoked response, spontaneous (i.e. task-unrelated) activity in the brain is also abundant. Notably, spontaneous activity is considered unconscious. For example, spontaneous activity in the FFA is not associated with conscious awareness of a face. The question is: what is the difference at the neural level between stimulus-evoked activity in a case that this activity is associated with conscious awareness of some content (e.g. activity in the FFA in response to fully visible face stimuli) and spontaneous activity in that same region of the brain? To answer this question, in the present study, we had a rare opportunity to record two face-selective multi-units in the vicinity of the FFA in a human patient. We compared multi-unit face-selective task-evoked activity with spontaneous prestimulus and a resting-state activity. We found that when activity was examined over relatively long temporal windows (e.g. 100–200 ms), face-selective stimulus-evoked firing in the recorded multi-units was much higher than the spontaneous activity. In contrast, when activity was examined over relatively short windows, we found many cases of high firing rates within the spontaneous activity that were comparable to stimulus-evoked activity. Our results thus indicate that the sustained activity is what might differentiate between stimulus-evoked activity that is associated with conscious awareness and spontaneous activity.

Human neuronal activity, recorded in vivo from microelectrodes, may offer valuable insights into physiological mechanisms underlying human cognition and pathophysiological mechanisms of brain diseases, in particular epilepsy. Continuous and long-term recordings are necessary to monitor non predictable pathological and physiological activities like seizures or sleep. Because of their high impedance, microelectrodes are more sensitive to noise than macroelectrodes. Low noise levels are crucial to detect action potentials from background noise, and to further isolate single neuron activities. Therefore, long-term recordings of multi-unit activity remains a challenge. We shared here our experience with microelectrode recordings and our efforts to reduce noise levels in order to improve signal quality. We also provided detailed technical guidelines for the connection, recording, imaging and signal analysis of microelectrode recordings.During the last 10 years, we implanted 122 bundles of Behnke-Fried hybrid macro-microelectrodes, in 56 patients with pharmacoresistant focal epilepsy. Microbundles were implanted in the temporal lobe (74%), as well as frontal (15%), parietal (6%) and occipital (5%) lobes. Low noise levels depended on our technical setup. The noise reduction was mainly obtained after electrical insulation of the patient's recording room and the use of a reinforced microelectrode model, reaching median root mean square values of 5.8 µV. Seventy percent of the bundles could record multi-units activities (MUA), on around 3 out of 8 wires per bundle and for an average of 12 days. Seizures were recorded by microelectrodes in 91% of patients, when recorded continuously, and MUA were recorded during seizures for 75 % of the patients after the insulation of the room. Technical guidelines are proposed for (i) electrode tails manipulation and protection during surgical bandage and connection to both clinical and research amplifiers, (ii) electrical insulation of the patient's recording room and shielding, (iii) data acquisition and storage, and (iv) single-units activities analysis.We progressively improved our recording setup and are now able to record (i) microelectrode signals with low noise level up to 3 weeks duration, and (ii) MUA from an increased number of wires . We built a step by step procedure from electrode trajectory planning to recordings. All these delicate steps are essential for continuous long-term recording of units in order to advance in our understanding of both the pathophysiology of ictogenesis and the neuronal coding of cognitive and physiological functions.

Temporal pole epilepsy (TPE) is a poorly known and difficult to individualize subtype of temporal lobe epilepsy. Consequently, in drug-resistant TPE, there is still a debate on the need for a large surgical removal of the temporal pole and mesial temporal structures or a limited resection of the temporal pole. We reviewed all patients who underwent presurgical evaluation for drug-resistant epilepsy over a 17-year period, and report here 19 patients with proven drug-resistant temporal pole epilepsy who underwent a selective temporal pole resection with respect to mesial structures. Most (15) TPE patients exhibited seizures resembling mesiotemporal seizures, whereas the others exhibited nocturnal hyperkinetic seizures or an association of both seizure types. MRI revealed a temporal pole lesion in 58% of patients. Long-term postoperative outcome after a conservative surgery was excellent: 63% of patients were seizure-free (International League Against Epilepsy [ILAE] 1) at 1-year postsurgery and 78% at 5 years. These results show that TPE has no specific electroclinical features but is a distinct type of temporal lobe epilepsy allowing a conservative surgery. Respecting the mesiotemporal structures is a valid surgical approach for drug-resistant temporal pole epilepsy.

International audience; Epileptic syndromes are distinctive disorders with specific features, which when taken together, permit a specific diagnosis. There is actually a debate on that medial temporal lobe epilepsy with hippocampal sclerosis is an epileptic syndrome. To address this issue, we searched for discriminative semiological features between temporal lobe epilepsy patients with hippocampal sclerosis (TLE-HS patients or group 1), TLE patients with medial structural lesion other than hippocampal sclerosis or in MRI-negative cases with medial onset on further investigations (group 2) and lateral TLE patients (LTLE or group 3). We retrospectively collected data from medical and EEG-video records of 523 TLE patients, referred for surgery to the Pitié-Salpêtrière Epileptology Unit between 1991 and 2014. We identified 389 patients belonging to group 1, 61 patients belonging to group 2, and 73 patients belonging to group 3 and performed a comparative analysis of their clinical data and surgical outcomes. TLE-HS patients (group 1): (1) began epilepsy earlier (11 ± 9 vs. 20 ± 10 vs. 15 ± 9 years); (2) exhibited more frequently early febrile convulsions (FC) (59 vs 7 vs 5%); (3) presented more: ictal gestural automatisms (90 vs 54 vs 67%), dystonic posturing (47 vs 20 vs 23%), and secondary generalized tonic–clonic seizures (GTCS) (70 vs 44% vs 48%) as compared to both groups 2 and 3 patients (all p < 0.001). With respect to auras, abdominal visceral auras were more reported by TLE-HS than by LTLE patients (49 vs 16%). Three cardinal criteria correctly classified 94% of patients into TLE-HS group: history of FC, dystonic posturing, and secondary GTCS. Postoperative outcome was significantly better in TLE-HS group than in the two other groups (p = 0.03 and 0.003). Our study demonstrates that cardinal criteria are reliably helpful to distinguish patients with TLE-HS from those with other TLE and may allow considering TLE-HS as a distinctive syndrome.

Objective The scope of unconscious cognition stretched its limits dramatically during the last 40 years, yet most unconscious processes and representations that have been described so far are fleeting and very short-lived, whereas conscious representations can be actively maintained in working memory for a virtually unlimited period. In the present work we aimed at exploring conscious and unconscious lasting (>1 second) expectancy effects. Methods In a series of four experiments we engaged participants in the foreperiod paradigm while using both unmasked and masked cues that were informative about the presence/absence of an upcoming target. We recorded behavioral responses, high-density scalp EEG (Exp. 2a), and intra-cranial EEG (Exp. 2b). Results While conscious expectancy was associated with a large behavioral effect (~150 ms), unconscious expectancy effect was significant but much smaller (4 ms). Both conscious and unconscious expectancy Contingent Negative Variations (CNVs) originated from temporal cortices, but only the late component of conscious CNV originated from an additional source located in the vicinity of mesio-frontal areas and supplementary motor areas. Finally, only conscious expectancy was accessible to introspection. Conclusions Both unmasked and masked cues had an impact on response times and on brain activity. Significance These results support a two-stage model of the underlying mechanisms of expectancy.

Transthyretin familial amyloid polyneuropathy (FAP) is a rare disease with autosomal transmission due to point mutation of the transthyretin (TTR) gene. It is the most disabling hereditary neuropathy affecting sensory, motor and autonomic nerves, and is irreversible and fatal within 7 to 12 years of onset in the absence of therapy. Diagnosis is usually delayed for 1-5 years because the onset is usually insidious, and a positive family history is lacking in 50% of late-onset cases. Penetrance is variable, and depends of the age of the carrier and age of onset in family members. Two treatments are available: liver transplantation, to suppress the main source of systemic production of mutant TTR; and TTR tetramer stabilizer drugs, to avoid the release of highly amyloidogenic monomers and oligomers. These therapies are able to stop or slow the progression of the disease in its early stages. Genetic counseling is crucial to detect carriers at risk of developing the disease. The European network for TTR-FAP recommends careful baseline assessment by questionnaire, clinical examination and neurophysiological tests, and periodic consultations to detect the onset of disease in time to start anti-amyloid therapy after biopsy findings of amyloid deposition. A therapeutic educational program is important for improving patients' awareness. Patients are considered symptomatic and ill when they themselves perceive symptoms or changes, including changes from baseline measurements on neurophysiological tests, followed by findings of amyloid deposition on biopsy. The most sensitive biopsies are from the labial salivary gland and skin.

In patients with pharmaco-resistant focal epilepsies investigated with intracranial electroencephalography (iEEG), direct electrical stimulations of a cortical region induce cortico-cortical evoked potentials (CCEP) in distant cerebral cortex, which properties can be used to infer large scale brain connectivity. In 2013, we proposed a new probabilistic functional tractography methodology to study human brain connectivity. We have now been revisiting this method in the F-TRACT project (f-tract.eu) by developing a large multicenter CCEP database of several thousand stimulation runs performed in several hundred patients, and associated processing tools to create a probabilistic atlas of human cortico-cortical connections. Here, we wish to present a snapshot of the methods and data of F-TRACT using a pool of 213 epilepsy patients, all studied by stereo-encephalography with intracerebral depth electrodes. The CCEPs were processed using an automated pipeline with the following consecutive steps: detection of each stimulation run from stimulation artifacts in raw intracranial EEG (iEEG) files, bad channels detection with a machine learning approach, model-based stimulation artifact correction, robust averaging over stimulation pulses. Effective connectivity between the stimulated and recording areas is then inferred from the properties of the first CCEP component, i.e. onset and peak latency, amplitude, duration and integral of the significant part. Finally, group statistics of CCEP features are implemented for each brain parcel explored by iEEG electrodes. The localization (coordinates, white/gray matter relative positioning) of electrode contacts were obtained from imaging data (anatomical MRI or CT scans before and after electrodes implantation). The iEEG contacts were repositioned in different brain parcellations from the segmentation of patients' anatomical MRI or from templates in the MNI coordinate system. The F-TRACT database using the first pool of 213 patients provided connectivity probability values for 95% of possible intrahemispheric and 56% of interhemispheric connections and CCEP features for 78% of intrahemisheric and 14% of interhemispheric connections. In this report, we show some examples of anatomo-functional connectivity matrices, and associated directional maps. We also indicate how CCEP features, especially latencies, are related to spatial distances, and allow estimating the velocity distribution of neuronal signals at a large scale. Finally, we describe the impact on the estimated connectivity of the stimulation charge and of the contact localization according to the white or gray matter. The most relevant maps for the scientific community are available for download on f-tract. eu (David et al., 2017) and will be regularly updated during the following months with the addition of more data in the F-TRACT database. This will provide an unprecedented knowledge on the dynamical properties of large fiber tracts in human. he research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 616268 “F-TRACT”. All the computations presented in this paper were performed using the CIMENT infrastructure (https://ciment.ujf-grenoble.fr), which is supported by the Rhône-Alpes region (GRANT CPER07_13 CIRA: http://www.ci-ra.org). We thank Bruno Bzenik and Romain Cavagna for their help on the CIMENT facility, and Jean-François Mangin and Cyril Poupon from Neurospin, CEA Saclay, for providing us with the ARCHI DTI database.

Focal seizures are assumed to arise from a hypersynchronous activity affecting a circumscribed brain region. Using microelectrodes in seizure-generating deep mesial regions of 9 patients, we investigated the firing of hundreds of single neurons before, during, and after ictal electroencephalogram (EEG) discharges. Neuronal spiking activity at seizure initiation was highly heterogeneous and not hypersynchronous. Furthermore, groups of neurons showed significant changes in activity minutes before the seizure with no concomitant changes in the corresponding macroscopic EEG recordings. Altogether, our findings suggest that only limited subsets of neurons in epileptic depth regions initiate the seizure-onset and that ictogenic mechanisms operate in submillimeter-scale microdomains. Ann Neurol 2017 Ann Neurol 2017;82:1022-1028.

To delineate the clinical and EEG features of adults with focal epilepsy associated with a generalized paroxysmal fast activity (GPFA) pattern on EEG who developed refractory seizures, notably drop attacks, but do not fulfill the classical triad for the diagnosis of Lennox–Gastaut syndrome (LGS) and provide further insight into LGS mechanisms. Among 957 patients admitted to video-EEG monitoring between 2002 and 2015, we retrospectively research adult patients with refractory focal epilepsy, drop attacks and GPFA on EEG. We collected demographic, anamnestic, and clinical data from medical records. We reviewed for all patients the interictal and ictal video-EEG recordings. We identified ten patients with focal epilepsy and electro-clinical features of LGS. As compared to classical LGS patients, our patients: (1) began epilepsy later (15.4 ± 8 years); (2) exhibited exclusively focal onset seizures, including drop attacks seizures linked to focal asymmetrical tonic posturing seizures; (3) had a stable cognition over time and (4) evolved favourably with a good secondary response to treatments in 80% of cases. Interestingly, all patients exhibited apparent diffuse interictal and ictal EEG abnormalities but a detailed analysis revealed that 50% had asymmetrical GPFA and 70% secondary bilateral synchrony processes. We may hypothesize here that a process of “secondary LGS” occurred which produced a worsening of seizures with the apparition of drop attacks and GPFA on EEG. This study brings arguments to consider that some cases of LGS could be linked to the development of a “secondary epileptic network” driven by a primary focal epileptic zone.

Objectif Le delai diagnostique de la narcolepsie de type 1 (NT1) reste de nos jours considerable. L’epilepsie constitue un diagnostic differentiel parfois delicat. Nous rapportons ici le cas d’un patient souffrant de « secousses du membre superieur », resistant a deux ans de traitement antiepileptique, dont l’analyse du monitorage video-electroencephalographique (EEG) a permis de porter un diagnostic de cataplexie partielle. Methodes Analyse video-EEG et electromyogramme (EMG) et recapitulatif des caracteristiques electrocliniques pouvant orienter entre les diagnostics d’epilepsie et de NT1. Resultats Le patient de 26 ans developpait des malaises brefs et stereotypes (secousses du membre superieur droit, trouble du langage, rares chutes). L’analyse de la video et de l’EMG permettait d’affirmer la presence d’une atonie partielle intermittente, notamment faciale, a l’origine d’un emoussement du langage, et de secousses des membres superieures, voisines de myoclonies negatives. Le diagnostic de NT1 etait confirme par l’etude du sommeil. Nous resumons les caracteristiques d’atonie liee a la NT1 et aux syndromes epileptiques bien definis (syndrome de Doose et de Lennox Gastaut, souvent associes a un retard mental), et ceux d’autres mecanismes de chute (myoclonies positives, asystolie ictale). Conclusion La NT1 continue de poser de difficultes diagnostiques, notamment dans un contexte de cataplexie partielle pretant a confusion avec l’epilepsie focale.

International audience; OBJECTIVE:The reasons for failure of surgical treatment for mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) remain unclear. This retrospective study analyzed seizure, cognitive, and psychiatric outcomes, searching for factors associated with seizure relapse or cognitive and psychiatric deterioration after MTLE-HS surgery.METHODS:Seizure, cognitive, and psychiatric outcomes were reviewed after 389 surgeries performed between 1990 and 2015 on patients aged 15-67 years at a tertiary center. Three surgical approaches were used: anterior temporal lobectomy (ATL; n = 209), transcortical selective amygdalohippocampectomy (SAH; n = 144), and transsylvian SAH (n = 36).RESULTS:With an average follow-up of 8.7 years (range = 1.0-25.2), seizure outcome was classified as Engel I in 83.7% and Engel Ia in 57.1% of patients. The histological classification of HS was type 1 for 75.3% of patients, type 2 for 18.7%, and type 3 for 1.2%. Two factors were significantly associated with seizure recurrence: past history of status epilepticus and preoperative intracranial electroencephalographic recording. In contrast, neither HS type, the presence of a dual pathology, nor surgical approach was associated with seizure outcome. Risk of cognitive impairment was 3.12 (95% confidence interval = 1.27-7.70), greater in patients after ATL than in patients after transcortical SAH. A presurgical psychiatric history and postoperative cognitive impairment were associated with poor psychiatric outcome.SIGNIFICANCE:The SAH and ATL approaches have similar beneficial effects on seizure control, whereas transcortical SAH tends to minimize cognitive deterioration after surgery. Variation in postsurgical outcome with the class of HS should be investigated further.

From the very beginning the seizure prediction community faced problems concerning evaluation, standardization, and reproducibility of its studies. One of the main reasons for these shortcomings was the lack of access to high-quality long-term electroencephalography (EEG) data. In this article we present the EPILEPSIAE database, which was made publicly available in 2012. We illustrate its content and scope. The EPILEPSIAE database provides long-term EEG recordings of 275 patients as well as extensive metadata and standardized annotation of the data sets. It will adhere to the current standards in the field of prediction and facilitate reproducibility and comparison of those studies. Beyond seizure prediction, it may also be of considerable benefit for studies focusing on seizure detection, basic neurophysiology, and other fields.

International audience; PURPOSE: Idiopathic generalized epilepsies (IGE) are age-related epileptic syndromes mainly described in children and adolescence. Our aim is to describe their electroclinical features in the elderly. METHODS: Patients aged 70 years or more were prospectively selected in a geriatric EEG laboratory on the basis of rhythmic generalized spikes and waves discharges. Their clinical data were then examined to ascertain the syndromic diagnosis. RESULTS: Among 1181 geriatric patients referred for EEG over a 30-month period, IGE were identified in 10 cases. Eight patients began seizures in childhood or adulthood (3 childhood absence epilepsies, 2 juvenile/adult myoclonic epilepsies and 3 epilepsies with-generalized-tonic-clonic-seizures alone (EGTCS)) and 2 very late in life with EGTCS. The early-onset IGE cases had usually experienced a quiescent long period in adulthood before relapsing late in life. This relapse, mostly severe, consisted of absence status, myoclonic status or repeated generalized tonic clonic seizures and was often not-situation related. Absence status and myoclonic status were stopped by Clonazepam. The two late-onset IGE cases had familial history of epilepsy. Inappropriate antiepileptic drugs (AED) previously given in four patients with two worsenings were corrected. CONCLUSIONS: In this study, the non-negligible number of elderly cases observed over a short period of time suggests that IGE are frequent in the elderly but underestimated until recently. IGE may be lifelong with late severe exacerbations. A few very late-onset IGE cases exist. EEG remains useful in contributing to diagnose IGE and AED adjustment continues to be beneficial at extreme age.

Resume Introduction De nombreux arguments cliniques, metaboliques et electrophysiologiques suggerent l’existence d’un etat precritique, transition entre l’etat intercritique et la crise. Etat des connaissances L’analyse de l’EEG intracrânien par des methodes mathematiques a montre l’existence de changements de la dynamique cerebrale plusieurs minutes avant la survenue de crises partielles. Ces modifications dynamiques precritiques ne semblent pas limitees au foyer epileptogene, ce qui explique qu’elles puissent aussi etre apprehendees par l’EEG de scalp et dans des epilepsies partielles qu’un foyer epileptogene soit ou non identifie. Plusieurs scenarios peuvent rendre compte de la periode precritique : recrutement progressif des neurones, comme le suggerent des analyses a un niveau cellulaire, ou etat facilitateur, a haute probabilite de survenue de crises, comme le suggerent des analyses a l’echelle de reseaux neuronaux. Aucune methode de prediction des crises ne peut aujourd’hui etre proposee aux patients, car le taux de faux-positifs reste trop important. Perspectives Une etude multicentrique europeenne ( Evolving platform for improving living expectation of patients suffering from IctAl events [EPILEPSIAE]) evalue actuellement une combinaison de plus de 44 methodes d’analyse des signaux EEG et ECG, sur des enregistrements issus d’une vaste base de donnees. Conclusion D’importants efforts doivent etre poursuivis en combinant les analyses de signaux a de multiples niveaux : EEG intracrânien, microelectrodes intracerebrales, EEG de scalp, analyse in vitro de tissus post-operatoires.

Objectif Etudier un phenomene moteur epileptique subintrant non eveillant et discuter les mecanismes. Methodes Analyse d’un enregistrement EEG-EMG-video de sieste chez une femme de 22 ans, qui presente des crises motrices focales dans un contexte d’encephalite auto-immune liee a des anticorps anti-Hu. Resultats Vingt-sept crises epileptiques ont ete enregistrees durant le stade N2 (n = 13, duree moyenne 40,3 s) et N3 (n = 14, duree moyenne 16,7 s). Elles se sont manifestees par une elevation tonique suivie de clonies rythmiques du membre inferieur gauche bien visibles et audibles sans reveiller la patiente. Sur le plan EEG, les crises en N2 s’accompagnaient : – de rythmes theta 6–7 Hz diffus meles a des complexes K (n = 7), associes a une augmentation de la frequence cardiaque (FC) de 8,4 bat/min en moyenne ; – ou de complexes K repetitifs (n = 6), associes a une augmentation de FC de 5,5 bat/min. Les crises en N3 s’accompagnaient d’une majoration d’ondes lentes deltas (n = 7) ou non (n = 7). La FC etait peu augmentee de 2,4 bat/min (n = 7) ou inchangee. Absence de modification du sommeil en post-critique. Conclusion Chez cette patiente, les reponses d’eveil cerebral liees aux crises sont de differents niveaux mais peu intenses, souvent sous la forme de microeveils hautement synchrones (complexes K geants et ondes lentes deltas) exercant un effet anti-eveil efficace permettant de maintenir la continuite du sommeil. L’absence de reponse d’eveil visible (clinique, EEG et autonomique) lors de certaines crises en sommeil profond suggere un mecanisme de defense d’eveil encore plus efficace.

Le concept d’epilepsies generalisees idiopathiques est aujourd’hui remis en question, en particulier dans le cas des absences. Les etudes recentes ont souligne le role majeur de reseaux corticaux distribues dans la propagation des pointe-ondes (PO) d’absence. Cependant, elles ne renseignent pas sur les mecanismes de l’apparition de la premiere PO. Notre etude s’interesse a la caracterisation des activites corticales precoces participant a l’initiation des absences. Pour cela, nous avons explore la dynamique spatiotemporelle des interactions au sein et entre des reseaux corticaux locaux, modelises par des sources distribuees sur l’ensemble du cortex, sur la base d’enregistrements magnetoencephalographiques (MEG) de crises d’absence spontanees. A partir de leurs analyses temps-frequence, nous avons extrait la synchronisation locale de chaque source corticale, et la synchronisation a distance liant des sites distants. Nos analyses revelent une sequence reproductible : desynchronisation a distance – augmentation de la synchronisation locale – augmentation de la synchronisation a distance. Bien que synchronisations locale et a distance montrent des profils spatiotemporels differents, leurs localisations sur le cortex au sein d’une fenetre temporelle d’initiation se recoupent en un reseau multifocal, frontocentral. Ces observations contredisent la notion d’une activite soudainement generalisee dans les crises d’absence.

Resume Introduction Les etudes de suivi a long terme des epilepsies generalisees idiopathiques (EGI) indiquent un faible taux de remission, suggerant leur persistance a un âge avance. La frequence des EGI dans cette tranche d’âge reste cependant incertaine. Methodes Les EEG de 700 patients consecutifs de plus de 70 ans a l’hopital Charles-Foix ont ete inspectes a la recherche d’anomalies evocatrices d’EGI ; l’histoire des patients ayant ces anomalies a ete revue. Resultats Quatre patientes (âge moyen de 79 ans) furent retenues et presentaient une EGI ancienne : deux une epilepsie myoclonique juvenile et deux une epilepsie avec crises grand mal. Le diagnostic d’EGI n’etait pas connu et leur maladie n’etait pas ou peu active avant l’hospitalisation. L’evenement revelateur fut un episode plus grave que d’habitude : etat d’absence (EA), crises myocloniques subintrantes ou crises generalisees convulsives (CGC). La decouverte du diagnostic a permis de guider la prise en charge therapeutique : arret d’une aggravation iatrogene, initiation ou continuation d’un traitement adapte. Conclusions Les EGI peuvent se manifester a un âge avance par une exacerbation des crises, incluant EA, myoclonies subintrantes et CGC repetees, apres une longue periode quiescente. Elles ne semblent pas rares mais, difficiles a identifier, elles sont vraisemblablement sous-estimees. Leur diagnostic est pourtant un gage de reussite therapeutique.

International audience; The relationship between neural oscillations recorded at various spatial scales remains poorly understood partly due to an overall dearth of studies utilizing simultaneous measurements. In an effort to study quantitative markers of attention during reading, we performed simultaneous magnetoencephalography (MEG) and intracranial electroencephalography (iEEG) recordings in four epileptic patients. Patients were asked to attend to a specific color when presented with an intermixed series of red words and green words, with words of a given color forming a cohesive story. We analyzed alpha, beta, and gamma band oscillatory responses to the word presentation and compared the strength and spatial organization of those responses in both electrophysiological recordings. Time-frequency analysis of iEEG revealed a network of clear attention-modulated high gamma band (50-150 Hz) power increases and alpha/beta (9-25 Hz) suppressions in response to the words. In addition to analyses at the sensor level, MEG time-frequency analysis was performed at the source level using a sliding window beamformer technique. Strong alpha/beta suppressions were observed in MEG reconstructions, in tandem with iEEG effects. While the MEG counterpart of high gamma band enhancement was difficult to interpret at the sensor level in two patients, MEG time-frequency source reconstruction revealed additional activation patterns in accordance with iEEG results. Importantly, iEEG allowed us to confirm that several sources of gamma band modulation observed with MEG were indeed of cortical origin rather than EMG muscular or ocular artifact.

Resume Introduction De definition relativement recente, le syndrome de psychose post-ictale (PPI) fait partie de la famille des psychoses epileptiques, et se distingue, selon la classification la plus utilisee, des psychoses ictales, d’une part, et des psychoses inter-ictales, d’autre part. Objectif Le present article propose de faire le point sur les aspects cliniques des PPI a partir d’une description de quatre cas individuels et d’une revue de la litterature. Methodes Les cas cliniques presentes concernent quatre patients epileptiques, hospitalises pour video EEG en unite d’epileptologie au CHU de la Pitie-Salpetriere entre 2001 et 2005. Resultats Les PPI concernent presque exclusivement des patients atteints d’une epilepsie partielle pharmacoresistante evoluant depuis plusieurs annees et le plus souvent d’origine temporale. Les troubles psychotiques apparaissent avec un intervalle libre apres une salve de crises partielles complexes volontiers secondairement generalisees. Pendant toute la phase psychotique, aucune activite critique epileptique n’est enregistree sur le trace EEG. Le tableau psychiatrique est marque par des idees delirantes de persecution, des hallucinations acousticoverbales et visuelles, ainsi que des troubles du comportement (agitation, agressivite). Les troubles de l’humeur sont variables, souvent fluctuants chez un meme patient. Dans la majorite des cas, l’evolution a court terme est favorable sous traitement antipsychotique. A plus long terme, le risque principal est la recidive. Cependant, une evolution vers des troubles de l’humeur avec tentatives de suicide ou vers une psychose inter-ictale chronique est possible. La physiopathologie des PPI demeure aujourd’hui inconnue. Conclusion Le syndrome de PPI, s’il est de bon pronostic a court terme, peut potentiellement evoluer vers d’autres troubles psychiatriques de moins bon pronostic. Il est donc important a connaitre pour le clinicien, d’autant que son traitement apparait relativement aise par rapport a celui d’autres troubles psychotiques. Ce traitement devra neanmoins faire l’objet d’etudes controlees pour parvenir a un consensus concernant la prise en charge de ce syndrome.

Objective To compare the performance of 4h-video EEG monitoring (VEEG) and 1h-nap-VEEG in an Epileptology Unit. Methods We examined short-term VEEG data from 196 patients admitted to characterize their: (i) clinical events; (ii) epileptic syndromes or (iii) state after status epilepticus or surgery. We compared the 4h-VEEG and 1h-nap-VEEG performances using three measures: (i) the capability to detect epileptic seizures (ES), psychogenic non-epileptic seizures (PNES), interictal epileptiform abnormalities (IEA) and sleep-related IEA; (ii) the usefulness to answer questions on referral; (iii) the sensitivity for the final diagnosis. Results The 4h-VEEG test recorded clinical events in 53.6% of 196 patients, IEA in 41.3%, sleep-related IEA in 34.7%, and was judged as useful in 66.8%. The 4h-VEEG was compared to the 1h-nap-VEEG in 129 patients. 4h-VEEG had a better capability to record clinical events (50.3% vs. 6.2%, p usefulness (63.5% vs . 37.2%, p sensitivity for both ES (69.3% vs. 49.3%, p =0.0035) and PNES (61.3% vs. 15.4%, p =0.0014) than nap-EEG. Conclusions This work found 4h-VEEG records were superior to the 1h-nap-VEEG test on the basis of three complementary measures, capability, usefulness and sensitivity. Significance 4h-VEEG is a useful alternative investigation tool in an Epileptology Unit.

A 69-year-old woman had insomnia, restless legs syndrome, and violent movements during sleep; she had had a generalized seizure several years previously. She underwent 4 days of video-EEG investigation for these movements (table, and figure e-1 on the Neurology ® Web site at [Neurology.org][1]). There was no epileptic activity, but repetitive, stereotyped movements (88 movements/hour; movement duration: 2.5 seconds) occurred only during sleep, which were typical of periodic leg movements but associated with atypical, polyphasic hand cycling/rubbing movements (see video). This complex motor pattern might be confused with a focal epileptic seizure. [1]: http://neurology.org/lookup/doi/10.1212/WNL.0000000000002224

International audience; Invasive electroencephalography recordings with depth or subdural electrodes are necessary to identify the ictogenic area in some drug-resistant focal epilepsies. We aimed to analyze the safety profile of intracranial electrode implantation in a tertiary center and the factors associated with its complications. We retrospectively examined complications in 163 intracranial procedures performed in adult patients. Implantation methods included oblique depth stereotactic approach (n = 128) and medial-temporal depth stereotactic approach in combination with subdural strip placement (n = 35). 1201 depth macroelectrodes, 59 bundles of microelectrodes (in 30 patients) and 148 subdural electrodes were implanted. Complications were classified as major (requiring treatment or leading to neurological impairment) or minor. The rate of overall complications was 4.9 % (n = 8), with 3.1 % (n = 5) of major complications, though no permanent morbidity or mortality was recorded. Infection occurred in 1.2 % and hemorrhage in 3.7 % of patients. One hemorrhage occurred for every 225 electrodes implanted (4.4 ‰). Microelectrodes were not responsible for any complications. Overall and hemorrhagic complications were significantly associated with MRI-negative cases (7.3 and 6.3 % versus 0 %, p = 0.04). We believe that intracranial electrode implantation has a favorable safety profile, without permanent deficit. These risks should be balanced with the benefits of invasive exploration prior to surgery. Furthermore, this study provides preliminary evidence regarding the safety of micro-macroelectrodes.

International audience; Analysing the clinical characteristics of seizures constitutes a fundamental aspect of the presurgical evaluation of patients with medial temporal lobe epilepsy and unilateral hippocampal sclerosis (MTLE-HS), the most frequent form of focal epilepsy accessible to surgery. We sought to retrospectively determine whether objective manifestations could have a reliable lateralizing value in a large population of MTLE-HS patients and if their presence could help to identify those patients who would be seizure free after surgery. We analysed the frequency and predictive lateralizing value of objective ictal and postictal signs in 391 patients with MTLE-HS (183 left/208 right). Data were derived from chart review and not from blinded videoEEG analysis. Correlation between the presence of reliable lateralizing signs and postoperative outcome was performed in a subgroup of 302 patients who underwent surgery. Contralateral dystonic posturing was the most frequent and reliable lateralizing sign that correctly lateralized the focus in 96% of patients. Unilateral head/eye deviation was noted in 42% of the patients and predicted unilateral focus in 67%. Ipsilateral postictal nose wiping, contralateral clonus and hypokinesia correctly lateralized the focus in 75%, 81%, respectively, and 100 of patients but were less frequently depicted. Postictal aphasia was a strong lateralizing sign for left MLE-HS. The presence of reliable lateralizing signs was not a predictor of seizure freedom. Seizure semiology is a simple tool that may permit reliable lateralization of the seizure focus in MTLE-HS. The presence of reliable lateralizing signs is not associated with a better postoperative outcome.

Summary: Purpose: To assess the seizure-freedom rates and self-perceived psychosocial changes associated with the long-term outcome of epilepsy surgery in patients with refractory medial temporal lobe epilepsy associated with hippocampal sclerosis. Methods: A standard questionnaire was given to 183 patients who underwent surgery between 1988 and 2004, and 110 were completed. Results: The mean duration of follow-up after surgery was 7 years, with a maximum of 17 years. The probability that patients were seizure-free after surgery was dependent on the definition of the seizure freedom. For the patients who were seizure-free since surgery (Engel's class Ia), the probability was 97.6% at 1 year after surgery, 85.2% at 2 years after surgery, 59.5% at 5 years after surgery, and 42.6% at 10 years after surgery. For the patients who still experienced rare disabling seizures after surgery but were seizure-free at least 1 year before the time of assessment, the probability was of 97.6% at 1 year after surgery, 95% at 2 years after surgery, 82.8% at 5 years after surgery, and 71.1% at 10 years after surgery. The psychosocial long-term outcome, as measured by indices of driving, employment, familial and social relationships, and marital status, was similar to the psychosocial short-term outcome. It did not depend on seizure freedom or on follow-up time interval and was not influenced statistically by seizure frequency in cases of persisting seizures. Most but not all patients noticed a substantial overall improvement in their psychosocial condition; 48% drove (increased by 7%), 47% improved (14% worsened) in their employment status, and 68% improved (5% worsened) in their familial and social relationships. Overall, 91% of patients were satisfied with the surgery, and 92% did not regret their decision. Conclusions: The results of this study suggest that temporal lobe surgery has real long-term benefits. Two specific conclusions emerge: (a) the long-term rates of freedom from seizure depend on how seizure freedom is defined, and (b) the psychosocial long-term outcome does not change dramatically over years and does not depend on seizure freedom.

The quantification of phase synchrony between brain signals is of crucial importance for the study of large-scale interactions in the brain. Current methods are based on the estimation of the stability of the phase difference between pairs of signals over a time window, within successive frequency bands. This paper introduces a new approach to study the dynamics of brain synchronies, Frequency Flows Analysis (FFA). It allows direct tracking and characterization of the nonstationary time-frequency dynamics of phase synchrony among groups of signals. It is based on the use of the one-to-one relationship between frequency locking and phase synchrony, which applies when the concept of phase synchrony is not taken in an extended 'statistical' sense of a bias in the distribution of phase differences, but in the sense of a continuous phase difference conservation during a short period of time. In such a case, phase synchrony implies identical instantaneous frequencies among synchronized signals, with possible time varying frequencies of synchronization. In this framework, synchronous groups of signals or neural assemblies can be identified as belonging to common frequency flows, and the problem of studying synchronization becomes the problem of tracking frequency flows. We use the ridges of the analytic wavelet transforms of the signals of interest in order to estimate maps of instantaneous frequencies and reveal sustained periods of common instantaneous frequency among groups of signal. FFA is shown to track complex dynamics of synchrony in coupled oscillator models, reveal the time-frequency and spatial dynamics of synchrony convergence and divergence in epileptic seizures, and in MEG data the large-scale ongoing dynamics of synchrony correlated with conscious perception during binocular rivalry.

PURPOSE: Ictal single-photon emission computed tomography (SPECT) may help localize the seizure-onset zone (SOZ) by detecting changes in regional cerebral blood flow induced by epileptic discharges. This imaging method also reveals hyperperfusions in areas of seizure propagation, including the hemisphere contralateral to the SOZ. We have studied the occurrence, the topography, and the clinical value of such contralateral ictal hyperperfusion areas (HPAs). METHODS: We examined data from presurgical evaluations of 36 consecutive patients with pharmacoresistant partial epilepsy of various localizations. Ictal and interictal SPECT examinations were made with 99mTc-ECD, and the scans were processed for coregistration, normalization, subtraction, and merging with MRI images. RESULTS: Contralateral HPAs were observed in 72% of the patients: 50% of mesiotemporal epilepsy cases with hippocampal sclerosis, 85.7% of the other mesiotemporal epilepsies, 85.7% of neocortical lateral temporal epilepsies, and 87.5% of extratemporal epilepsies. Contralateral HPAs were usually symmetrical to the SOZ, forming a mirror image, observed in 57.1% of the patients. They could be slightly asymmetrical in mesiotemporal epilepsies, perhaps because of the particular anatomic pathways linking temporal lobes. In neocortical epilepsies, they were located in the cortex homotopic to the SOZ. CONCLUSIONS: We show that the symmetrical nature of the mirror image usually does not disturb SPECT interpretation. It can confirm the location of the SOZ (11 patients) and even occasionally improve the precision of its definition (nine patients) by restraining several potential SOZ-related HPAs to a single one or by permitting a restricted localization of the SOZ in a large HPA.

Objectif Il est connu que le sommeil paradoxal inhibe mais localise mieux les anomalies epileptiques intercritiques. Peu de donnees sont disponibles pour savoir s’il aide a mieux analyser les crises partielles que les autres stades de veille-sommeil. Methodes Les donnees video-EEG de surface ont ete analysees pour 162 crises (72/veille, 57/sommeil lent, 33 CESP (crises en sommeil paradoxal)) chez 15 patients epileptiques (âge moyen 35 ± 8,2 ans) ayant une epilepsie partielle (de localisation temporale 10/15). Resultats Les CESP ont montre un debut plus focal chez 2 patients, un developpement mieux lateralise chez 3 patients, compares aux crises des autres stades (ces 5 patients ont tous une epilepsie temporale). Mais les debuts plus focaux et la meilleure lateralisation confirmaient les autres donnees sans modifier le diagnostic topographique final et la strategie d’investigation pre-chirurgicale. De meme, pour un patient ayant une epilepsie bitemporale, un debut unilateral etait du meme cote de l’hypo-metabolisme au PDG-PET. La comparaison durant differents stades montre que les crises en sommeil lent ou paradoxal sont moins affectees par les artefacts que celles pendant la veille (15 % vs 43 %, p = 0,0003). La periode de “silence d’artefacts musculaires” au debut de la crise est plus longue en sommeil paradoxal (16,1 ± 9,3 sec) que pendant la veille (9,7 ± 7,2 sec, p = 0,003) ou en sommeil lent (11,6 ± 10,6 sec, p = 0,048). Conclusion La lecture des crises peut etre plus facile lors du sommeil paradoxal mais globalement la valeur ajoutee de ce dernier reste peu contributive en pratique clinique.

Introduction The frequency of local oscillations and inter-regional synchrony has been correlated with the engagement of cognitive operations. Notwithstanding, adding causality to these associations requires the direct manipulation of brain rhythms Noninvasive stimulation with single pulses of TMS coupled to scalp-EEG recordings has provided evidence of local increases in power at specific frequency bands, likely to reflecting the local “natural” frequencies as defined by Rosanova et al. (2009). Mapping of these phenomena across human brain areas is paramount for understanding the neural coding mechanisms involved in information transfer and to further develop the use of exploratory and therapeutic neuromodulation. Objectives Mapping the human anatomical and physiological causal features of spreading natural oscillations across brain regions by co-localizing an atlas of structural connectivity with a map of functional interactions based on the distribution of rhythmic activity enabled by intracortical stimulation. Methods We analyzed intracranial EEG signals from 8 epilepsy patients implanted with depth multielectrodes in frontal, prefrontal, parietal and temporal areas, the amygdala and the hippocampus. We analyzed in the frequency-domain oscillatory activity elicited by single electrical pulses delivered through pairs of adjacent contacts, as recorded by the remaining contacts, and modeled a map of effective connectivity. Individual anatomical maps of white matter fasciculi were tracked individually and co-localized with the former. Results Single electrical pulses induced frequency-specific modulations of power in contacts not employed to deliver the pulses. Oscillatory enhancements were influenced by both the local anatomical environment and the estimated probability of white matter connections between stimulated and recorded sites. Conclusions Our results support the feasibility of studying functional connectivity patterns by analyzing the local induction and network spread of natural oscillation frequencies, enabled by single pulses of intracranial stimulation and to co-register them with white matter connectivity maps. This approach might contribute to the compilation whole-brain connectivity atlases able to categorize oscillation frequency to behavioral relationships throughout brain regions and their connections in humans.

Obstructive sleep apnea (OSA) is common in patients with refractory epilepsy and may exacerbate seizures. In epileptic patients with OSA, seizures occur more frequently during sleep. Seizure frequency may be reduced by treating OSA and increase if the treatment is interrupted or neglected. It is not clear how OSA provokes seizures. Multiple seizureprovoking factors including cerebral hypoxemia, sleep deprivation and sleep fragmentation might be involved. The temporal link between OSA and seizures or interictal events might be better understood with careful analysis of video EEG (vEEG) records. Such data has never been precisely reported. We report here a direct relation between OSA and both ictal and interictal epileptic events during vEEG investigations in a patient with temporal lobe epilepsy.

International audience; Background and purpose : Medial temporal lobe epilepsy with unilateral hippocampal sclerosis (MTLE-HS) is the most frequent form of surgical temporal lobe epilepsy. In this study, it was aimed to determine whether different types of aura represent a cardinal and characteristic feature of MTLE-HS and might provide a diagnostic complement to help identify patients who will be seizure-free after surgery.Methods : All types of auras and associations of auras reported by 400 MTLE-HS patients referred for surgery were retrospectively collected and their statistical correlation with the postoperative outcome was examined in a subgroup of 305 patients who underwent surgery.Results : A total of 876 auras were collected, classified into 12 categories. Globally, MTLE-HS patients reported widely variable auras and groupings of auras. Most common were autonomic and abdominal visceral auras, followed by psychoaffective and experiential auras; less common, but seen in 10%–15% of patients, were non-specific auras, somatosensory auras and visual auras, and least common, reported by less than 10% of patients, were auditory, gustatory, vestibular, olfactory and intellectual auras. No auras were reported in 10% of patients. 65% of patients experienced more than one type of aura (two to seven). No specific groupings of aura type were apparent. No evidence was found for correlation between postoperative outcome and (i) any category of aura, (ii) the number of categories of aura per patient and (iii) any association of categories of auras.Conclusion : Auras and association of auras vary widely in MTLE-HS and provide no useful insight into surgical outcome.

Background:We examined the lateralizing value of postictal language and motor deficits and studied their underlying mechanisms.Patients and methods:The total sample consisted of 35 patients (26 temporals, 8 frontals, 1 parietal) with a good postsurgical outcome (Engel's class I and II). Postictal examination was blindly reviewed on videotapes. In 15 cases (29 seizures), postictal language manifestations were analyzed in relation with the diffusion of the epileptic discharge recorded by intracerebral EEG. Language dominance was determined by the intracarotid amobarbital test.Results:Postictal aphasia was observed only when (1) seizure originated in the dominant hemisphere and (2) ictal activity spread to language areas (Wernicke and/or Broca areas). When the epileptic focus was in the nondominant hemisphere, no postictal aphasia was observed even if there was secondary generalization of ictal activity affecting the language areas of the dominant hemisphere. Postictal motor deficits also had a strong lateralizing value even when seizures were secondarily generalized.Conclusion:Postictal aphasia in temporal epilepsies and postictal motor deficits in temporal and extra temporal epilepsies provided excellent lateralizing information. Postictal deficits appear to be the result of inhibitory mechanisms induced by previous ictal activity of the structures related to these functions.

Seizures associated with toothbrushing have been reported in patients with precentral or postcentral partial epilepsy. Seizures precipitated by thinking have been described in patients with idiopathic generalized epilepsy. We report a patient with intractable partial epilepsy in which seizures were induced both by toothbrushing, and by seeing or thinking about toothbrush and toothpaste. Video-EEG analysis revealed a left temporal lobe origin for these reflex seizures. We discuss how complex multimodal stimuli may trigger these reflex seizures.

Summary: Purpose: The validity and clinical significance of dipole modeling in epilepsy surgery candidates is not fully established. Patients and Methods: Interictal and ictal dipole modeling was performed in 43 patients with refractory complex partial seizures (CPS) and intracranial structural abnormalities demonstrated with optimum magnetic resonance imaging (MRI: space–occupying, n = 15; atrophic, n = 26; dysplastic, n = 2). Video–EEG monitoring showed CPS in all patients. In 12 patients, additional intracranial EEG monitoring demonstrated hippocampal seizure onset in 11 patients and medial occipital ictal onset in 1. Results: Spatiotemporal dipole mapping of averaged interictal spikes and epochs of early ictal discharges revealed two distinct dipole patterns. Patients with lesions located in the medial (± lateral) temporal lobe (n = 34) and medial occipital lobe (n = 1) uniformly presented a combined interictal dipole that consisted of a radial and a tangential component with a high degree of elevation relative to the axial plane. Eight of 9 patients with extratemporal lesions had a less stable dipole with a predominant radial component. Ictal dipole modeling identified the ictal onset zone correctly as compared with intracranial EEG recordings from bilateral hippocampal depth electrodes. Ictal dipoles showed a striking correspondence with the interictal dipoles in individual patients. Conclusions: Interictal and ictal dipole mapping provided additional, reliable, and relevant localizing information in surgical candidates for refractory CPS. Ictal dipole analysis may limit the number of patients who require intracranial electrodes.

International audience; 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.

Introduction - To evaluate the homogeneity of patients operated on for MTLE. Material and methods - 30 consecutive patients prospectively investigated with clinical, EEG, neuropsychology, MRI, FDG-PET criteria and eventually intracranial EEG, who underwent antero-medial temporal resection (follow-up : 24 months). Results - Clear and well-lateralised MTLE was non-invasively ascertained in 22 patients (73%). Eight patients (27%) had a less pure presentation due to divergent scalp EEG features (bitemporal, widespread or extratemporal), unusual auras or absence of MRI-based hippocampal sclerosis or FDG-PET hypometabolism. They were explored by invasive monitoring which confirmed medial temporal origin of seizures. Outcome was excellent in 95% of the pure cases (Engel's class I) and less favorable in the more difficult ones (65% of class I). Conclusions - MTLE criteria, including the strong contribution of brain imaging, permit to select accurately a large percentage of patients. However a consistant number of patients present a less pure presentation suggesting more complex epileptogenic networks.

We examined the prognostic value of spatial and temporal characteristics of intracerebral propagation of seizures during temporal lobe epilepsy (TLE) surgery. Seven TLE patients resistant to standard anterotemporal lobectomy who had no known causes of resistance [e.g., extratemporal (ET), lesions, multifocal epilepsy] were matched with 7 seizure-free patients and 7 others who were almost seizure-free after operation. Intracerebral ictal propagation pathways were not different in the three groups. Propagation was multidirectional, most frequently to the frontal lobes and sometimes to the contralateral temporal lobe (CTL). ET propagation delays were significantly shorter in resistant patients than in markedly improved patients. The resistant group also had more frequent propagation delays1.0 s, but propagation times1.0 s were equally likely in all groups. The extent of ET propagation and frequency of focal onsets were not different among the groups. Results suggest that very short propagation times predict reduced efficacy of operation, and that long propagation times are not related to surgical success.

International audience; Surgical outcome in patients with nonlesional refractory partial epilepsies could be improved by a more precise definition of the epileptogenic zone (EZ). The value of interictal FDG-PET hypometabolism, voxel-based-morphometry (VBM) and diffusion tensor imaging (DTI) is still debated. We compared the sensitivity and specificity of these noninvasive techniques in localizing the EZ with stereo-electroencephalography (SEEG) results. Twenty patients with nonlesional partial epilepsy (13 temporal lobe epilepsy (TLE) and 7 extra-temporal (extra-TLE)) underwent structural MRI, DTI and FDG-PET. FDG-PET was analyzed visually (vPET) blinded and unblinded and by statistical parametric mapping (SPM) (sPET). Individual modifications of grey matter volume and mean diffusivity increase were compared to a control group with SPM. The best sensitivity was provided by vPET unblinded (75%) and the best specificity (60%) by DTI. The sensitivity of vPET blinded (55%) was lower and those of sPET (40%) and VBM (35%) were still lower. In TLE, vPET analyzed either blinded or unblinded, performed the best and additional use of the other tools improved slightly the sensitivity. For extra-TLE, combining vPET and DTI results increased the number of pertinent abnormalities detected especially for circumscribed changes in frontal lobe epilepsy (FLE). Combining vPET and DTI was the more efficient strategy for extra-TLE, allowing the detection of pertinent abnormalities in FLE when FDG-PET alone was not contributive. Combining sPET or VBM with vPET was less useful.

International audience; Inferring someone's personality from his or her photograph is a pervasive and automatic behavior that takes place even if no reliable information about one's character can be derived solely from facial features. This illustrates nicely the idea that perception is not a passive process, but rather an active combination of current sensory inputs with endogenous knowledge derived from prior experience. To understand how and when neural responses to faces can be modulated by prior experience, we recorded magneto-encephalographic (MEG) responses to new faces, before and after subjects were exposed for a short period of 15-20 min to an experimentally induced association between a facial feature (inter-eye distance) and a response (personality judgment). In spite of the absence of any observable response bias following such a short reinforcement phase, our experimental manipulation influenced neural responses to faces as early as 60-85 ms. Source localization of magneto-encephalographic signals, confirmed by intracranial recordings, suggests that prior experience modulates early neural processing along two initially independent neural routes, one initiated in an anterior system that includes the orbitofrontal cortex and the temporal poles, and the second one involving face-sensitive regions in the ventral visual pathway. The two routes are both active as early as 60 ms but engage in reciprocal interactions only later, between 135 and 160 ms. These experimental findings support recent models assuming the existence of a fast anterior pathway activated in parallel with the ventral visual system which would link prior experience with current sensory inputs.

Objective To examine in detail the relations between seizures and K-complexes in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). Methods Prolonged continuous video-EEG recording and analysis of 30 seizures in an 18-year-old woman suffering from ADNFLE with a CHRNA4 gene mutation. Results Twenty-seven of 30 recorded seizures started just after a K-complex. In nine cases a sound induced a K-complex that was immediately followed by the seizure. Most seizures preceded repetitive and brief ictal restarts. Conclusions Three new characteristics have been observed in this ADNFLE patient: a K-complex is almost invariably present at seizure onset; sounds trigger some seizures; ictal restarts occur often. Significance These new observations – the presence of K-complexes at seizure onset and occurrence of sound-triggered seizures – support the view that ADNFLE seizures may be initiated by K-complexes.

Objectif Comparer les mouvements et vocalisations lors de crises epileptiques survenues au cours du sommeil paradoxal (CESP) et lors du trouble comportemental en sommeil paradoxal (TCSP). Methodes Les donnees video-EEG ont ete analysees lors de 27 CESP de 14 patients epileptiques (âge moyen 30,2 ans, 9 femmes, la plupart avec une epilepsie temporale, unite d’epileptologie) et 120 episodes de TCSP chez 12 patients (âge moyen 62,7 ans, 11 hommes, service des pathologie du sommeil). Resultats Les episodes de CESP sont plus longs (53 s) que ceux de TCSP (23 s). Les patients ouvrent plus souvent les yeux (91 % contre 10 %), manipulent plus les objets a leur portee (54 % contre 4,2 %), semblent reprendre conscience (87 % contre 12,6 %) et s’etirent plus souvent (30,7 % contre 6,6 %). Ils presentent plus des gestes auto-centres (34,7 % contre 12,5 %) et moins de gestes diriges vers l’exterieur (0 % contre 19,3 %). Les reniflements, gemissements, changements respiratoires et la toux sont presque uniquement observes pendant les CESP et presque jamais lors de TCSP. La posture dystonique caracterise les CESP mais elle est loin d’etre systematique (6/27). Les mouvements de tout le corps ou de la hanche sont plus frequents dans le groupe avec CESP et inversement pour les diverses secousses non cloniques. Il n’y pas de difference pour les vocalisations. Conclusion Certains symptomes (yeux ouverts, gestes autocentres, reniflement, etirement, toux, posture dystonique, longue duree de l’episode) distinguent bien les CESP du TCSP, ce qui pourrait aider au diagnostic differentiel des l’etape de l’interrogatoire.

Summary: Purpose: To search for a recovery after surgery of mean diffusivity (MD) values in the contralateral nonsclerotic hippocampus of patients with medial temporal lobe epilepsy (MTLE) and hippocampal sclerosis (HS). Methods: Twenty-four MTLE patients (12 right-sided and 12 left-sided MTLE) and 36 healthy volunteers were investigated using diffusion tensor imaging. A region-of-interest approach was used to measure pre- and postoperative interictal hippocampal MD values in patients. Results: Diffusion abnormalities in contralateral nonsclerotic hippocampus recovered after surgery (p < 0.0001). A subgroup of 14 patients exhibited a clear increase in MD values whereas the remaining 10 patients were stable. No significant difference was found between the two subgroups for each of the electroclinical data studied including early postoperative outcome, all patients being either seizure free or with rare persistent auras. Conclusions: This finding suggests that diffusion abnormalities in contralateral hippocampus may represent a functional mechanism linked to the active epileptic process.

Objective To report complete change of seizure and spike lateralization over time in bilateral temporal lobe epilepsies (TLE). Methods Repetition of video-EEG monitorings in 115 patients; 2 cases are reported in detail; 113 other severe partial epilepsies were included to estimate retrospectively the frequency of the reported phenomenon. Results In 2 cases, two video-EEG monitorings, separated by several months, revealed the first time one unilateral TL (temporal lobe) seizure and spike focus and the second time a distinct seizure and spike focus located in the opposite TL. The second monitoring was planned for these two patients because of the presence of a discordant lesion or, in the absence of a lesion, of some bilateral or discordant functional (EEG, SPECT and PET) abnormalities. No patient among the other 113 cases had this video-EEG pattern. Conclusions In TLE, two video-EEG sessions may be necessary to disclose two opposite TL epileptogenic foci. Significance In rare bilateral TLE cases, the expression of seizure and spike foci can alternate between hemispheres.

International audience; Interictal diffusion imaging studies in patients with medial temporal lobe epilepsy (MTLE) accompanied by hippocampal sclerosis (HS) have shown an increased diffusivity in the epileptogenic hippocampus. In this study, we wanted to explore the whole brain in order to determine if MTLE could have an impact on the organization and the architecture of a large cerebral network and to identify clinical factors that could mediate diffusion abnormalities. Diffusion tensor imaging (DTI) and statistical parametric mapping of the entire brain were performed in 35 well-defined MTLE patients and in 36 healthy volunteers. SPM analyses identified three abnormal areas: an increased diffusivity was detected in the epileptic hippocampus and the ipsilateral temporal structures associated with a decreased anisotropy along the temporal lobe, a decreased diffusivity was found in the contralateral non-sclerotic hippocampus, the amygdala, and the temporal pole, and finally, a decreased anisotropy was noted ipsilaterally in posterior extratemporal regions. Duration of epilepsy, age at onset, and the frequency of generalized tonic-clonic seizures or partial complex seizures did not correlate with the presence of diffusion abnormalities. Region of interest analysis in the hippocampus/parahippocampus demonstrated a correlation between lower ipsilateral diffusivity values and occurrence of epigastric aura and between higher anisotropy values in both hemispheres and history of febrile seizures. In conclusion, this study showed that diffusion abnormalities are not restricted to the pathologic hippocampus and involve a larger network. This pattern may indirectly reflect the epileptogenic network and may be interpreted as a cause or a consequence of epilepsy.

In a patient with unilateral hippocampal sclerosis, stimulation of the contralateral anterior perirhinal cortex triggered after-discharges in the sclerotic hippocampus, followed in one case by a seizure. The spatial and temporal characteristics of these responses reveal fast interconnections between the two medial temporal lobes.