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To determine the prognostic value of conventional electroencephalography (EEG) monitoring in neonatal hypoxic-ischemic encephalopathy (HIE).In this multicentre retrospective study, 95 full-term neonates (mean of 39.3wks gestational age [SD 1.4], 36 [38%] females, 59 [62%] males) with HIE (2013-2016) undergoing therapeutic hypothermia were divided between favourable or adverse outcomes. Background EEG activity (French classification scale: 0-1-2-3-4-5) and epileptic seizure burden (epileptic seizure scale: 0-1-2) were graded for seven 6-hour periods. Conventional EEG monitoring was investigated by principal component analysis (PCA), with clustering methods to extract prognostic biomarkers of development at 2 years and infant death.Eighty-one per cent of infants with an adverse outcome had a French classification scale equal to or greater than 3 after H48 (100% at H6-12). The H6-12 epileptic seizure scale was equal to or greater than 1 for 39%, increased to 52% at H30-36 and then remained equal to or greater than 1 for 39% after H48. Forty-five per cent of infants with a favourable outcome had a H6-12 French classification scale equal to or greater than 3, which dropped to 5% after H48; 13% had a H6-12 epileptic seizure scale equal to or greater than 1 but no seizures after H48. Clustering methods based on PCA showed the high efficiency (96%) of conventional EEG monitoring for outcome prediction and allowed the definition of three prognostic EEG biomarkers: H6-78 French classification scale mean, H6-78 French classification scale slope, and H30-78 epileptic seizure scale mean.Early lability and recovery of physiological features is prognostic of a favourable outcome. Seizure onset from the second day should also be considered to accurately predict neurodevelopment in HIE and support the importance of conventional EEG monitoring in HIE in infants cooled with therapeutic hypothermia.Comprehensive analysis showed the high prognostic efficiency (96%) of conventional electroencephalography (EEG) monitoring. Prognostic EEG biomarkers consist of the grade of background EEG activity, its evolution, and the mean seizure burden. Persistent seizures (H48) without an improvement in background EEG activity were consistently associated with an adverse outcome.

Electroencephalography (EEG) is the reference tool for the analysis of brain function, reflecting normal and pathological neuronal network activity. During the neonatal period, EEG patterns evolve weekly, according to gestational age. The first analytical criteria for the various maturational stages and standardized neonatal EEG terminology were published by a group of French neurophysiologists training in Paris (France) in 1999. These criteria, defined from analog EEG, were completed in 2010 with digital EEG analysis. Since then, this work has continued, aided by the technical progress in EEG acquisition, the improvement of knowledge on the maturating processes of neuronal networks, and the evolution of critical care. In this review, we present an exhaustive and didactic overview of EEG characteristics from extremely premature to full-term infants. This update is based on the scientific literature, enhanced by the study of normal EEGs of extremely premature infants by our group of neurophysiologists. For educational purposes, particular attention has been paid to illustrations using new digital tools.

International audience; Sleep is a key process in neurodevelopment and essential for the maturation of fundamental brain functions. Premature birth can disturb the initial steps of sleep maturation, which may contribute to the impairment of neurodevelopment. It is thus fundamental to understand the maturation of the various sleep states and the quality of cerebral function in each vigilance state, as well as the development of sleep cyclicity, in at-risk neonatal infants, particularly those born premature. The objective of this review is to provide a precise description of sleep states and cycles and their rhythmic organization in premature and term newborns according to their gestational age. Technical aspects of polysomnography, which requires a high level of expertise in neonates, are also described. Principles of the visual interpretation of polysomnography, including the simultaneous analysis of behavioral (spontaneous motricity and eye movements), polysomnographic parameters (electro-oculogram, electrocardiogram, respiration), and electroencephalography patterns are presented. The neurophysiology of sleep ontogenesis and its interaction with brain maturation are discussed, highlighting the crucial-role of sleep states and their duration in premature newborns. In particular, the involvement of myoclonic twitches in functional connectivity in sensorimotor development is discussed. Indeed, sleep quality, determined by combined polysomnographic parameters, reflects either normal or pathological developmental processes during the neonatal period. The fundamental place of neurophysiological explorations in the early detection of sleep disorders is discussed, as well as their potential consequences on neurodevelopmental care to improve the prevention of neurodevelopmental impairment. (C) 2020 Elsevier Masson SAS. All rights reserved.

Electroencephalography (EEG) of neonatal patients is amongst the most valuable diagnostic and prognostic tool. EEG recordings, acquired at the bedside of infants, evaluate brain function and the maturation of premature and extremely premature infants. Strict conditions of acquisition and interpretation must be respected to guarantee the quality of the EEG and ensure its safety for fragile children. This article provides guidance for EEG acquisition including: (1) the required equipment and devices, (2) the modalities of installation and asepsis precautions, and (3) the digital signal acquisition parameters to use during the recording. The fundamental role of a well-trained technician in supervising the EEG recording is emphasized. In parallel to the acquisition recommendations, we present a guideline for EEG interpretation and reporting. The successive steps of EEG interpretation, from reading the EEG to writing the report, are described. The complexity of the EEG signal in neonates makes artefact detection difficult. Thus, we provide an overview of certain characteristic artefacts and detail the methods for eliminating them.

International audience; We report on a 7-year-old female who presented paroxysmal episodes of loss of consciousness with clonic movements. The electroencephalogram (EEG) evidenced diffuse slow wave activations, with no symptoms. Epilepsy was suspected but antiepileptic drugs were ineffective. Video-EEG monitoring revealed that the syncope was triggered by stretching with a tachycardia that started during the stretch maneuver and diffuse slow waves on the EEG 2s before the symptoms. Stretch syncope can result in striking manifestations with subcortically driven clonic movements that can be mistaken for signs of epilepsy. Stretching might lead to transient hypoxia of the brainstem; in turn, this might activate the thalamocortical loop and thus generate cardiovascular changes, EEG slow waves, and physical manifestations.

Electroencephalography is the only clinically available technique that can address the premature neonate normal and pathological functional development week after week. The changes in the electroencephalogram (EEG) result from gradual structural and functional modifications that arise during the last trimester of pregnancy. Here, we review the structural changes over time that underlie the establishment of functional immature neural networks, the impact of certain anatomical specificities (fontanelles, connectivity, etc.) on the EEG, limitations in EEG interpretation, and the utility of high-resolution EEG (HR-EEG) in premature newborns (a promising technique with a high degree of spatiotemporal resolution). In particular, we classify EEG features according to whether they are manifestations of endogenous generators (i.e. theta activities that coalesce with a slow wave or delta brushes) or come from a broader network. Furthermore, we review publications on EEG in premature animals because the data provide a better understanding of what is happening in premature newborns. We then discuss the results and limitations of functional connectivity analyses in premature newborns. Lastly, we report on the magnetoelectroencephalographic studies of brain activity in the fetus. A better understanding of complex interactions at various structural and functional levels during normal neurodevelopment (as assessed using electroencephalography as a benchmark method) might lead to better clinical care and monitoring for premature neonates.

Objective: Characterization of the spatial and temporal dynamics of interictal epileptic discharges (IED) using time-frequency analysis (TFA) and electrical-source localization (ESL). Methods: TFA was performed on IED (spikes, spike waves, and polyspike waves) recorded by high-density-EEG (HD-EEG) in 19 refractory focal epileptic children. Temporal modulations related to IEDs were analyzed in a time window around the IED peaks [-1,000 to 1,000 ms]. Spatial modulations were analyzed by ESL in the time-frequency and time domains. Results: IED were associated with complex power spectral modulations. We observed increases in power spectrum (IPS) patterns specific to IED type. For spikes, the TFA pattern consisted of an IPS (-100 to +100 ms, 4-50 Hz). For spike waves, the IPS was followed by a second IPS (+100 to +400 ms, 4-10 Hz), corresponding to the slow wave. IPS patterns were preceded (-400 to -100 ms, 4-40 Hz), and followed (+100 to +400 ms) by a decrease in the power spectrum (DPS) (n = 8). For 14 out of 19 patients, at least one ESL method was concordant with the epileptogenic area. For the remaining five patients, all of them had temporal epilepsies. ESL in the time-frequency domain (DPS/IPS) provided concordant (n = 6) or complementary (n = 4) information to the ESL in the time domain concerning the epileptogenic zone. ESL in time-frequency domain (DPS/IPS) was the only method to provide concordant information concerning the epileptogenic zone in three patients. Significance: TFA demonstrates complex time-frequency modulations of the neuronal networks around IED, suggesting that the pathological mechanisms are initiated well before onset of the classical hyper-synchronization of the IED. Combining time and time-frequency analysis of the ESL provides complementary information to define the epileptogenic zone in refractory focal epilepsy.

SummaryObjective Interictal epileptic spikes (IES) represent a signature of the transient synchronous and excessive discharge of a large ensemble of cortical heterogeneous neurons. Epilepsy cannot be reduced to a hypersynchronous activation of neurons whose functioning is impaired, resulting on electroencephalogram (EEG) in epileptic seizures or IES. The complex pathophysiological mechanisms require a global approach to the interactions between neural synaptic and nonsynaptic, vascular, and metabolic systems. In the present study, we focused on the interaction between synaptic and nonsynaptic mechanisms through the simultaneous noninvasive multimodal multiscale recording of high-density EEG (HD-EEG; synaptic) and fast optical signal (FOS; nonsynaptic), which evaluate rapid changes in light scattering related to changes in membrane configuration occurring during neuronal activation of IES. Methods To evaluate changes in light scattering occurring around IES, three children with frontal IES were simultaneously recorded with HD-EEG and FOS. To evaluate change in synchronization, time–frequency representation analysis of the HD-EEG was performed simultaneously around the IES. To independently evaluate our multimodal method, a control experiment with somatosensory stimuli was designed and applied to five healthy volunteers. Results Alternating increase–decrease–increase in optical signals occurred 200 ms before to 180 ms after the IES peak. These changes started before any changes in EEG signal. In addition, time–frequency domain EEG analysis revealed alternating decrease–increase–decrease in the EEG spectral power concomitantly with changes in the optical signal during IES. These results suggest a relationship between (de)synchronization and neuronal volume changes in frontal lobe epilepsy during IES. Significance These changes in the neuronal environment around IES in frontal lobe epilepsy observed in children, as they have been in rats, raise new questions about the synaptic/nonsynaptic mechanisms that propel the neurons to hypersynchronization, as occurs during IES. We further demonstrate that this noninvasive multiscale multimodal approach is suitable for studying the pathophysiology of the IES in patients.

Epilepsy with Centrotemporal Spikes (ECTS) is the most common form of self-limited focal epilepsy. The pathophysiological mechanisms by which ECTS induces neuropsychological impairment in 15-30% of affected children remain unclear. The objective of this study is to review the current state of knowledge concerning the brain structural and functional changes that may be involved in cognitive dysfunctions in ECTS. Structural brain imaging suggests the presence of subtle neurodevelopmental changes over the epileptogenic zone and over distant regions in ECTS. This structural remodeling likely occurs prior to the diagnosis and evolves over time, especially in patients with cognitive impairment, suggesting that the epileptogenic processes might interfere with the dynamics of the brain development and/or the normal maturation processes. Functional brain imaging demonstrates profound disorganization accentuated by interictal epileptic spikes (IES) in the epileptogenic zone and in remote networks in ECTS. Over the epileptogenic zone, the literature demonstrates changes in term of neuronal activity and synchronization, which are effective several hundred milliseconds before the IES. In the same time window, functional changes are also observed in bilateral distant networks, notably in the frontal and temporal lobes. Effective connectivity demonstrates that the epileptogenic zone constitutes the key area at the origin of IES propagation toward distant cortical regions, including frontal areas. Altogether, structural and functional network disorganizations, in terms of: (i) power spectral values, (ii) functional and effective connectivity, are likely to participate in the cognitive impairment commonly reported in children with ECTS. These results suggest a central and causal role of network disorganizations related to IES in the neuropsychological impairment described in ECTS children.

Surgery is increasingly proposed as a treatment for children with medically refractory partial epilepsy. The outcome after surgery depends on complete resection of the epileptogenic zone correlates. Despite multimodal preoperative assessment, 40–60% of children require intracranial electroencephalography (EEG) recording. Standard EEG can be easily performed with 20 to 30 electrodes in children of all ages. Increasing the number of electrodes (high-density [HD] EEG) significantly improves the spatial resolution of EEG and allows source localization of the epileptogenic focus. In adults, this technique has been validated for source localization of the epileptic focus and contributes to a better understanding of the neural networks involved in epilepsy. In this review, we discuss the pediatric specificities of HD EEG and source localization in order to define the value of this technique in the preoperative assessment of children with refractory partial epilepsy. Source localization using HD EEG requires several steps. The first step, elaboration of the head model, must take into account the heterogeneity of skull bone thickness, persistence of the fontanelles in younger infants, and the unknown conductivities of anatomical structures in children. The second step consists of defining the number of electrodes, which depends on the age and cortical gyration of the brain. Finally, after extraction of meaningful information (interictal or ictal features), the third step consists of defining the specific modalities required in pediatric subjects to resolve the inverse problem to determine source localization.

Benign epilepsy with centrotemporal spikes (BECTS) is the most common idiopathic childhood epilepsy, which is often associated with developmental disorders in children. In the present study, we analyzed resting state EEG spectral changes in the sensor and source spaces in eight BECTS patients compared with nine age-matched controls. Using high-resolution scalp EEG data, we assessed statistical differences in spatial distributions of EEG power spectra and cortical sources of resting state EEG rhythms in five frequency bands: δ (0.5–3.5 Hz), θ (4–8 Hz), α (8.5–13 Hz), β1 (13.5–20 Hz) and β2 (20.5–30 Hz) under the eyes-closed resting state condition. To further investigate the impact of centrotemporal spikes on EEG spectra, we split the EEG data of the patient group into EEG portions with and without spikes. Source localization demonstrated the homogeneity of our population of BECTS patients with a common epileptic zone over the right centrotemporal region. Significant differences in terms of both spectral power and cortical source densities were observed between controls and patients. Patients were characterized by significantly increased relative power in θ, α, β1 and β2 bands in the right centrotemporal areas over the spike zone and in the right temporo-parieto-occipital junction. Furthermore, the relative power in all bands significantly decreased in the bilateral frontal and parieto-occipital areas of patients regardless of the presence or absence of spikes in EEG segments. However, the spectral differences between patients and controls were more pronounced in the presence of spikes. This observation emphasized the impact of benign epilepsy on cortical source power, especially in the right centrotemporal regions. Spectral changes in bilateral frontal and parieto-occipital areas may also suggest alterations in the default mode network in BECTS patients., Highlights • BECTS patients exhibited enhanced θ activity over all cortical regions. • BECTS patients displayed reduced α activity at the occipital regions. • Patients showed increased power in θ, α, β in right temporo-parieto-occipital pole. • EEG spectral changes in BECTS patients indicate dysfunction at the epileptic zone. • EEG spectral changes in BECTS patients may show alteration in default mode network.

Objectives To better define the physiopathology of Interictal Epileptic Spikes (IES) and specially: (i) the mechanisms that propel neurons to hypersynchronizations, and (ii) the local and distant dynamic changes of neuronal population activities, we performed a time frequency analysis (TFA) of the surrounding activation of the IES. Methods HD EEG (64 and 128 electrodes) of 19 children (10 males; mean age 9.6 years), with refractory partial epilepsy of different aetiology, were analysed. Two types of IES were analyzed: spikes and poly-spike waves. TFA was performed on HD EEG epochs around the peak of IES (± 1000 ms). TFAs were calculated for frequencies between 4 and 50 Hz. Source localization was then performed from averaging spikes on EEG, from hypersynchronization, and from changes in TFA before hypersynchronization. Results Two time-frequency patterns were individualized: one specific for spike, the other specific for poly-spike-wave. TFA also revealed desynchronization around (before and after) hypersynchronization of IES (± 400 ms) in the epileptogenic zone, as already described in BECTS and in epileptic rats. At the lobar level the source localization was more accurate when performed during desynchronization (100%) than when performed during hypersynchronization (90%), and also than when performed on the peak of IES (74%) in the time domain. Discussion TFA with HD EEG in a children population of refractory partial epilepsy indicate complex changes in the dynamics of neuronal networks, not only during, but also before and after IES that is not specific to the type of epilepsy but to the type of IES. This provides new insight in the mechanism that propels neurons to synchronize. Source localization of IES should be performed during desynchronization, suggesting that the pathological activation already spread before the neuronal hypersynchronization of the IES.

Si le taux de survie des enfants prematures a augmente, cette population reste a haut risque de developper des troubles neurocognitifs, notamment pour les prematurites extremes. L’EEG est le meilleur outil d’exploration fonctionnelle cerebrale en periode neonatale, en faisant un excellent examen predictif du devenir neurodeveloppemental. Parmi ces elements predictifs, la duree des periodes de continuite et de discontinuite ajustee au terme gestationnel a ete identifiee comme l’un des neuro-biomarqueurs predictifs du devenir neurologique des prematures. L’objectif de notre travail etait de valider une methode automatique de detection des bouffees d’activites et des periodes de quiescence dans une population de prematures nes entre 24 et 28 SA. Ce travail constitue la premiere etape d’une etude visant a preciser, dans une large population, les neuro-biomarqueurs EEG predictifs du devenir neurologique chez des enfants suivis prospectivement jusqu’a l’âge de 2 ans. Nous avons analyse les EEG de 10 enfants nes avant 28 SA. Deux neurophysiologistes ont identifie de facon independante les bouffees d’activite et les periodes de quiescence. Dans un premier temps, la concordance inter-observateur de l’analyse visuelle a ete verifiee. Les periodes de concordance inter-observateurs ont ete considerees comme le gold standard permettant d’etudier la validite de l’outil de detection automatique et d’optimiser les parametres de detection. La concordance globale inter-observateur etait superieure a 80 %. Les periodes de concordance ont ete comparees aux resultats de la detection automatique, avec differents parametres de detection (filtres, seuils de detection, amplitude…). L’outil de detection automatique presentait des valeurs de sensibilite et de prediction positives et negatives satisfaisantes. Au total, La concordance entre les 2 observateurs concernant l’analyse visuelle etait excellente et les performances de l’outil de detection automatique etaient satisfaisantes. Cet outil apparait comme une alternative simple d’utilisation et fiable a l’analyse visuelle. Ces resultats seront confirmes sur une plus grande population.

Introduction Many questions concerning the mechanisms that drive neurons to hypersynchronize remain unsolved, but synaptic as well as non-synaptic events are likely to be involved. Here Optical Imaging (OI) of the epileptic brain by concomitant electroencephalography (FOS-ECoG/HD-EEG), allow investigating the changes in the cellular environment associated with Interictal Epileptic Spikes (IES). The FOS changes (milliseconds) are related to non-synaptic events neuronal activation while ECoG-HDEEG investigates the synaptic events related to the IES. Methods In 3 patients with frontal epileptic spikes, High-Density EEG (HD-EEG) was acquired with 64 electrodes. In 15 epileptic penicillin rats’ experiments, ECoG signals were acquired with two monopolar electrodes disposed over the somatosensory cortex. FOS were recorded with a frequency-domain spectrophotometer at a sampling rate of 62.5 Hz with 16/2 detectors and 4/2 sources in patients and rats respectively. In order to provide an independent control condition to evaluate the method and the specificity of FOS in IES, the FOS signal in response to electrical stimulation of the median nerve was evaluated in both species. Results In both species median nerve stimulation (mERP) induces similar changes in FOS signal consisted in an increase followed by a decrease in the FOS concomitant to the mERP. In both species, alternating increase–decrease-increase in FOS occurred 200 ms before to 180 ms after the IES peak. This started before any changes in EEG signal. Time–frequency domain ECoG-HD EEG analysis revealed alternating decrease-increase–decrease in the EEG spectral power concomitantly with changes in FOS during IES. The FOS response was weaker with a lower signal-to-noise ratio when recorded on the scalp than when recorded from the cortex.This suggests a tight relationship between (de) synchronization and neuronal volume changes during IES. Conclusion FOS-ECoG/HDEEG analysis revel complex changes surrounding the IES and illustrating the complexity of the underlying mechanisms of IES generation. These changes in the neuronal environment around IES in frontal lobe epilepsy in children and in rats raise new questions about the synaptic and non-synaptic mechanisms that propel the neurons to IES hypersynchronization. Because it unable to evaluate non-invasively the synaptic and non-synaptic compartments, this multiscale multimodal high temporal resolution approach offer the opportunity to thoroughly investigate the pathophysiology of the IES. FOS response was specific to exogenous stimuli or endogenous neuronal activation (IES). The observed responses in epileptic patients were similar to those on epileptic rats using similar acquisition protocol and data analysis processes. This suggests that the mechanisms involved are fairly specific to the epileptic spikes, independently of the species and of the type of epilepsy.

EEG is an important tool for early cerebral evaluation in neonatal hypoxo-ischemic encephalopathy (HIE). The aim of our study was to precise the EEG prognosis value before starting hypothermia and during 72 h hypothermia in neurodevelopment evaluation with at least 2 years clinical follow-up. We analyzed 98 newborns admitted for suspicion of HIE. First EEG was done before 6 h of life, it was surveyed continuously and analyzed twice a day during 72 H hypothermia and in 12 h following rewarming. EEG recordings were characterized according to the French classification. The neurologic outcome was assessed at 24 months. Eighty-four infants completed neurodevelopmental follow-up. 18 of newborns died during the neonatal period. Among the survivors, 64%, 21% and 15% had respectively normal, moderate and severe outcomes. The first EEG before hypothermia do not correlated with the neurodevelopmental outcome. On the other hand, The EEG characteristics between 36 and 60 h of life, correlated strongly with the outcome. Normal or mildly abnormal EEG (minor abnormalities or discontinuous tracing type A) after the first 48 h had 95% positive predictive value EEG for normal or moderate impairment at 2 years (negative predictive value 77%, specificity 91%). Severe EEG abnormalities (discontinuous tracing type B, paroxysmal or inactive tracings) within the first 48 h had respectively 96% and 76% negative and positive value for poor outcomes (severe outcome or death) (sensitivity 91% and specificity 89%).

Background Epilepsy with Centrotemporal Spikes (ECTS) is the most common form of self-limited focal epilepsy. The pathophysiological mechanisms by which ECTS induces neuropsychological impairment in 30% of affected children remain unclear. Objectives The objective is to review the current state of knowledge concerning the brain structural and functional changes that may be involved in cognitive dysfunctions in ECTS. Methods Publication indexed in Pubmed about structural and functional brain imaging in ECTS were reviewed. Results Structural brain imaging suggests the presence of subtle neurodevelopmental changes over the epileptogenic zone (EZ) and over distant regions, which evolves over time, especially in patients with cognitive impairment. This suggests that the epileptogenic processes might interfere with the dynamics of the brain development. Functional brain imaging demonstrates disorganization accentuated by IES. Changes in neuronal activity are described several hundred milliseconds before the IES in over the EZ and in bilateral distant networks. This is associated with alteration of global small-world properties towards a more random network. The direction of information flow demonstrates that, the epileptogenic zone constitutes the key area at the origin of IES propagation towards distant cortical regions. Conclusion Structural and functional network disorganizations, in terms of: (i) power spectral values, (ii) functional and effective connectivity, are likely to participate in the cognitive impairment reported in children with ECTS. These results suggest a central and causal role of network disorganizations related to IES in the neuropsychological impairment.

Background The early identification of preterm infants at high neurological risk is essential. EEG is the only functional tool, which allows evaluating the cerebral maturation during the neonatal period. One of the EEG neuro-biomarker is the length Burst Activity (BA) adjusted to Post-Menstrual Age (PMA). For extremely preterms, studies about the predictive value of EEG are scarce, based on visual analysis in small cohorts. Objectives The objective of our study was to characterize BA in a large cohort of extreme preterms, using an automated burst detection tool develop and optimize in our laboratory, and to correlate BA characteristics with the brain maturation and the neurological outcome. Methods A total number of 86 preterm infants born before 28 weeks GA at Amiens University Hospital were included. Outcome assessment was based on Denver Developmental Screening Test Scale, at 2 years. The first EEG of each infants recording before 30 weeks PMA was analyzed with the automated detection method. Results The mean BA duration was significantly higher for infants with favorable outcome compared to infants with unfavorable outcome. With the PMA, the cerebral maturation of infants with the favorable outcome is characterized by an increase of the mean BA duration associated with a decrease of the number of BA. Conversely, in case of unfavorable evolution, the mean BA duration remains below 10 s despite the increase of PMA. Conclusion Automatic BA tool allow evaluating the brain maturation in extremely preterms and defining objective neurobiomarker of neurodevelopmental outcome.

Among the epileptic syndromes occurring during infancy, which are mostly non-idiopathic and associated with a poor prognosis, benign infantile convulsions are characterized by a favourable evolution. This work aims to analyse and compare the clinical, EEG and outcome characteristics of familial benign infantile convulsions (FBIC) and non-familial benign infantile convulsions (NFBIC). This is a retrospective study, conducted between 1988 and 2008, in 40 infants who presented benign infantile seizures during the two first years of life. All of them had no personal history, normal psychomotor development, normal neurological examinations, no abnormalities on biological and radiological investigations and a favourable outcome. In 14 cases, there was a familial history of familial benign infantile convulsions. However, among the 26 cases with non-familial benign infantile convulsions, 11 children had a familial history of other epileptic syndrome. That may suggest a genetic familial susceptibility. In the two groups, the clinical features and the electroencephalography were similar. The seizures had short duration and occurred most often in clusters. Twenty-nine children had secondarily generalized partial seizures and 11 infants had generalized seizures but a focal onset cannot be excluded. The antiepileptic drugs allowed rapid resolution of seizures. One child necessitated a prolonged antiepileptic treatment. In the other cases, seizures cured in the first year without recurrence of seizures after treatment discontinuation. The evolution was characterised in five children by a later occurrence of dystonia. This subgroup was described as infantile convulsion and choreoathetosis syndrome (ICCA). Benign infantile convulsions are probably an underestimated epileptic syndrome. The diagnosis is relatively easy in the familial forms with dominant autosomal transmission. In contrast, in sporadic forms, the diagnosis can be confirmed only by the evolution. The good prognosis must be tempered by the subsequent onset of dystonia consisted in the ICCA syndrome and justifies a prolonged follow-up.

Inattention and hyperactivity/impulsivity are the core symptoms of Attention Deficit/Hyperactivity Disorder (ADHD). Slowness, although less known, has been also recently reported in children with ADHD and may contribute to their learning difficulties. Slow response time and greater response time variability have been highlighted by several computerized tasks. The goal of the present work was to evaluate the age-related response time in ADHD children and in a group of matched control children during an attentional capture paradigm. The study population included 75 children with ADHD (aged between 6 and 13) and 75 age- and gender-matched typical developing children (Control group). The children with ADHD made more errors than children on the control group. The response times and the response time variability decreased with age in both groups and were significantly greater in ADHD than in controls. The distractor effect was similar in both groups. The maturation of response times and response time variability with age is quite similar in children with ADHD and typical developing children but whatever the age-class, children with ADHD were slower and exhibited greater response time variability than control children that could explain the variation during day-time of attention capacities in ADHD.

Objectives EEG-HR source localization is a non-invasive method to better delineate the source of the epileptic activity and thus the schema for electrodes implantation. Such source localization method relies on solving an inverse problem. In this study we evaluate the impact of bone conductivity, different head models and filtering, different methods of localization, the number of electrodes and the selection of different parts of the interictal epileptic spike. Methods Two groups of patients were studied. The first group (n = 13) consists of patients with lesions on the MRI. They were recorded with 64 electrodes. The second group consists of non lesional patient but one (n = 7) they were recorded with 128 electrodes. In the first group, the impact of bone conductivity, different head models, different filtering, and different methods of localization and the selection of different parts of the interictal spike was evaluate through the Euclidian distance of the resulting dipoles. In the second group, the impact of the number of electrodes (n = 128/64/32) on the location of the dipole was evaluated. Results The selection of the different parts of the interictal epileptic spikes and the different inverse methods (dipolar/scanning) did not return any significant difference on the source localization. Different filtering and bone conductivities did not significantly impact the localization. The different head model (realistic/realist) had significant impact on the localization of the source. Using 128 electrodes improved significantly the accuracy of the source localization. Conclusion Controlling the different parameters involved in the source localization significantly improve the accuracy of the inverse methods used to delineate the localization of the source of the IES and thus might be helpful to precise the schema of electrodes implantation.

Objectives Hypoxo-ischemic encephalopathy (HIE) is by far the most frequent etiology in neonatal encephalopathy). It is an important cause of neonatal mortality and long-term neurosensorial and cognitive impairment. Therapeutic hypothermia is nowadays the only therapeutic neuroprotective mean to decrease second state lesions within 6 hours after hypoxo-ischemia with an effect on mortality and morbidity rates as well as on seizures. The aim of our study was to precise EEG criteria in starting hypothermia decision and in prognosis evaluation with at least 2 years clinical follow-up. Methods We analyzed 120 newborns admitted, between January 2013 and February 2015, in the neonatal intensive care for suspicion of HIE. First EEG was done before 6 hours of life, it was surveyed continuously and analyzed twice a day during 72-hour hypothermia and in 12 hours following rewarming. Three grades classification were used according to French EEG classification. EEG characteristics were analyzed for the decision of hypothermia and to determine prognosis in hours following warming and compared to the neurodevelopment evaluation at 2 years old using standardized scales. Results The evolution of infants with initial grades 0 or 1 EEG was characterized by normal or mild neurodevelopment impairment. Infants with initial grade 3 on EEG, without improvement within the first 48 hours were always associated with severe outcome (severe neurological impairment or death). For the other initial grade 3, who improve within the first 48 hours under hypothermia, as well as the initial grade 2, a variable outcome, between normal to severe neurological sequelae, were noted. Conclusion Our results confirmed that Conventional EEG remains the gold standard for hypothermia decision and in prognostic evaluation [1] , [2] . However, prospective longitudinal studies in large cohort are necessary to better clarify grade 2 EEG abnormalities in order to improve the prognosis evaluation; specially background and specific EEG pattern.

The non-invasive multimodal analysis of brain function in the premature babies makes it possible to evaluate the implementation of neural networks involved in various functions such as language. The establishment of neural networks is the result of (1) initial genetic factors that participate in the structural and functional development of networks, (2) endogenous stimuli-independent generators, (3) endogenous stimulus-dependent generators and (4) stimuli-dependant activations. Multimodal analysis, magnetic resonance imaging, optical imaging and high-resolution EEG (HR-EEG) source imaging enable the analysis of these initial premature networks. Thus, as early as 28 weeks gestational age, when the thalamocortical afferents start to connect the cortical plate, when perisylvian structures exhibit certain structural asymmetries, the neural network is able to discriminate voice and phonemes with a neural strategy involving synchronization habituation and mismatch in specific areas, suggesting a strong genetic fingerprint in these initial abilities. Using HR-EEG in premature makes it possible to demonstrate that some endogenous generators such as the theta temporal activities located in the posterior part of the temporal planum are stimuli-independent up to 30-week gestational age and probably participate in the early functional wiring of the perisylvian networks involved in language and communication functions.

Introduction High Density electroencephalography (HD EEG) is the reference non-invasive technique to investigate the dynamics of neuronal networks in Benign Epilepsy with Centro-Temporal Spikes (BECTS). Analysis of local dynamic changes surrounding Interictal Epileptic Spikes (IES) might improve our knowledge of the mechanisms that propel neurons to the hypersynchronization of IES in BECTS. Transient distant changes in the dynamics of neurons populations may also interact with neuronal networks involved in various functions that are impaired in BECTS patients. Methods HD EEG (64 electrodes) of eight well characterized BECTS patients (8 males; mean age: 7.2 years, range: 5–9 years) were analyzed. Unilateral IES were selected in 6 patients. They were bilateral and independent in 2 other patients. This resulted in a total of 10 groups of IES. Time–frequency analysis was performed on HD EEG epochs around the peak of the IES (±1000 ms), including phase-locked and non-phase-locked activities to the IES. The time frequency analyses were calculated for the frequencies between 4 and 200 Hz Results Time–frequency analysis revealed two patterns of dysregulation of the synchronization between neuronal networks preceding and following hypersynchronization of interictal spikes (±400 ms) in the epileptogenic zone. Dysregulation consists of either desynchronization (n = 6) or oscillating synchronization (n = 4) (4–50 Hz) surrounding the IES. The 2 patients with bilateral IES exhibited only local desynchronization whatever the IES considered. Distant desynchronization in low frequencies within the same window occurs simultaneously in bilateral frontal, temporal and occipital areas (n = 7). Conclusion Using time–frequency analysis of HD EEG data in a well-defined population of BECTS, we demonstrated repeated complex changes in the dynamics of neuronal networks not only during, but also, before and after the IES. In the epileptogenic zone, our results found more complex reorganization of the local network than initially thought. In line with previous results obtained at a microscopic or macroscopic level, these changes suggested the variability strategies of neuronal assemblies to raise IES. Distant changes from the epileptogenic zone in desynchronization observed in the same time window suggested interactions between larger embedded networks and opened new avenues about their possible role in the underlying mechanism leading to cognitive deficits.

Objective Although infantile spasms can be caused by a variety of etiologies, the clinical features are stereotypical. The neuronal and vascular mechanisms that contribute to the emergence of infantile spasms are not well understood. Methods We performed a multimodal study by simultaneously recording electroencephalogram and functional Near-infrared spectroscopy in an intentionally heterogeneous population of six children with spasms in series. Results Regardless of the etiology, spasms were accompanied by two phases of hemodynamic changes; an initial change in the cerebral blood volume (simultaneously with each spasm) followed by a neurovascular coupling in all children except for the one with a large porencephalic cyst. Discussion Changes in cerebral blood volume, like the neurovascular coupling, occurred over frontal areas in all patients regardless of any brain damage suggesting a diffuse hemodynamic cortical response. Significance The simultaneous motor activation and changes in cerebral blood volume might result from the involvement of the brainstem. The inconstant neurovascular coupling phase suggests a diffuse activation of the brain likely resulting too from the brainstem involvement that might trigger diffuse changes in cortical excitability.

Vagus nerve stimulation (VNS) has been demonstrated to be safe and effective for adults and children with drug-resistant epilepsy and is able to improve most types of epilepsy. The aim of this study, in a paediatric population, was to assess the overall efficacy of vagus nerve stimulation on seizures, to assess tolerability and quality of life.This single-centre, retrospective study reviewed the files of 29 children in whom a vagus nerve stimulator was implanted between 1995 and 2012. The response rate (greater than 50% reduction of the seizure frequency), antiepileptic efficacy according to the type of epilepsy or age at implantation or age at onset of epilepsy, the time-course of seizures, adverse effects, overall quality of life and number of hospitalisations were studied.In our population, vagus nerve stimulation achieved a significant reduction in the seizure frequency throughout follow-up (p = 0.015). Response rates were 59% at 3 months, and 66% at 6 months, and the response rate then remained stable at about 70%. Stimulation tended to be more effective in patients with non-idiopathic partial epilepsy than in patients with non-idiopathic and idiopathic generalised epilepsy (0.01p0.11). No other predictive factors of efficacy were identified. Patients, parents, caregivers reported improvement in overall quality of life in 38% of patients during clinical interviews. A significant reduction in the number of hospitalisations due to a reduction of seizure frequency was observed after implantation (p = 0.03). VNS was stopped because of complications or insufficient efficacy in 9 cases.Vagus nerve stimulation is a safe and effective treatment option in children with drug-resistant epilepsy who are not candidates for surgery.

Objective To evaluate the efectiveness of vagal stimulation in a population of children and adolescent with refractory epilepsy. Methods This is a monocentre, retrospective study, which studied the files of 29 children implanted between 1995 and 2012 with a vagus nerve stimulator. The rate of responders (reduction by more than 50% of the frequency of seizures), the antiepileptic efficacy according to the type of epilepsy or to the age of implantation or to the age of the start of epilepsy, the side effects, the overall quality of life and the number of hospitalisations were studied. Results VNS, for all types of epilepsy, brought a significant reduction of the frequency of seizures throughout the follow-up (p Conclusion The stimulation of the vagus nerve is a sure and effective therapeutic alternative that would be discussed for a child with refractory epilepsy when a surgical approach is not possible.