: Seizure onset zone imaging

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

IntrAnat Electrodes: A Free Database and Visualization Software for Intracranial Electroencephalographic Data Processed for Case and Group Studies

In some cases of pharmaco-resistant and focal epilepsies, intracranial recordings performed epidurally (electrocorticography, ECoG) and/or in depth (stereoelectroencephalography, SEEG) can be required to locate the seizure onset zone and the eloquent cortex before surgical resection. In SEEG, each electrode contact records brain’s electrical activity in a spherical volume of 3 mm diameter approximately. The spatial coverage is around 1% of the brain and differs between patients because the implantation of electrodes is tailored for each case. Group studies thus need a large number of patients to reach a large spatial sampling, which can be achieved more easily using a multicentric approach such as implemented in our F-TRACT project (f-tract.eu). To facilitate group studies, we developed a software—IntrAnat Electrodes—that allows to perform virtual electrode implantation in patients’ neuroanatomy and to overlay results of epileptic and functional mapping, as well as resection masks from the surgery. IntrAnat Electrodes is based on a patient database providing multiple search criteria to highlight various group features. For each patient, the anatomical processing is based on a series of software publicly available. Imaging modalities (Positron Emission Tomography (PET), anatomical MRI pre-implantation, post-implantation and post-resection, functional MRI, diffusion MRI, Computed Tomography (CT) with electrodes) are coregistered. The 3D T1 pre-implantation MRI gray/white matter is segmented and spatially normalized to obtain a series of cortical parcels using different neuroanatomical atlases. On post-implantation images, the user can position 3D models of electrodes defined by their geometry. Each electrode contact is then labeled according to its position in the anatomical atlases, to the class of tissue (gray or white matter, cerebro-spinal fluid) and to its presence inside or outside the resection mask. Users can add more functionally informed labels on contact, such as clinical responses after electrical stimulation, cortico-cortical evoked potentials, gamma band activity during cognitive tasks or epileptogenicity. IntrAnat Electrodes software thus provides a means to visualize multimodal data. The contact labels allow to search for patients in the database according to multiple criteria representing almost all available data, which is to our knowledge unique in current SEEG software. IntrAnat Electrodes will be available in the forthcoming release of BrainVisa software and tutorials can be found on the F-TRACT webpage

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Cartographies d épileptogénicité évaluées en SEEG : apport des oscillations hautes fréquences (60-100Hz) ictales dans la définition de la zone de début de crise

Les oscillations hautes fréquences (HFO) étudiées en stéréo-électroencéphalographie (SEEG) chez les patients présentant une épilepsie partielle pharmaco-résistante, semblent être le témoin de l épileptogénèse et reflètent assez fidèlement, par leur topographie, la seizure onset zone (SOZ). Récemment, notre équipe a fait état d une nouvelle méthode de cartographie de la SOZ basée sur l augmentation de puissance des HFO60-100 (HFO de fréquence comprise entre 60 et 100 Hz). Cette méthode, qui permet d établir une cartographie des réseaux neuronaux impliqués dans l initiation de la crise, a été appliquée à tous les patients implantés en SEEG entre 2009 et 2011 au CHU de Grenoble, qui avaient présenté au moins une crise épileptique spontanée. 21 patients ont ainsi été étudiés, de SOZ majoritairement néocorticale. La puissance ictale des HFO60-100 a été quantifiée pour chaque crise, puis des cartographies statistiques ont été utilisées pour représenter les régions corticales présentant une activation significative des HFO60-100 au début de la crise, comparativement aux HFO60-100 intercritiques. Pour tous les patients étudiés, une activation critique significative des HFO60-100 a été démontrée, quelle que soit la topographie de la SOZ, indépendamment de la présence d une lésion épileptogène. La topographie des HFO60-100 activées au début des crises semble corrélée à celle de la SOZ. Pour 11 des patients opérés, le pronostic chirurgical s avérait d autant plus favorable que la résection réalisée contenait les régions cérébrales présentant une activation significative des HFO60-100 ictales.High gamma oscillations (HFO, >60 Hz) at seizure onset are strongly associated to epileptogenesis, and their localising value for the seizure onset zone (SOZ) has been underlined using quantitative measures such as the epileptogenicity index. In particular, we recently reported a new method that produces images of epileptogenicity based on the detection of significant increase of HFO at seizure onset in stereotactic coordinates derived from patient s MRI (magnetic resonance imaging). Here, we applied the same analysis to 21 consecutive patients who underwent stereo-electroencephalography (SEEG) recordings between 2009 and 2011, and in whom at least one spontaneous seizure was recorded. Power of HFO ranging from 60 to 100Hz band (ictalHFO60-100) was quantified at onset for each seizure, and statistical parametric maps were used to represent the cortex areas displaying significant ictalHFO60-100 when compared to an interictal baseline. Analysis was performed at the patient level per seizure, with a group analysis for every patient. All patients presented a significant epileptogenicity map at seizure onset, whatever seizure onset location or histological lesion they had. IctalHFO60-100 map was highly reproducible over seizures per patient, and most significant ictalHFO60-100 had the same localisation as epileptogenic lesions. For 11 patients who underwent a 3DT1 MRI in the post-operative period, the removal of cortex areas displaying ictalHFO60-100 was associated to a better outcome. Epileptogenicity map is useful to evaluate the SOZ in the pre-surgical period. This new tool associated to SEEG might help to improve the surgical outcome of medically-intractable epilepsies.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

STRUCTURAL AND KINETIC PROPERTIES OF THE CYSTEINE SYNTHASE MULTI-ENZYME COMPLEX

International audienc

Epileptogenicity Maps of Intracerebral Fast Activities (60–100 Hz) at Seizure Onset in Epilepsy Surgery Candidates

International audienceFast activities (FA) at seizure onset have been increasingly described as a useful signature of the epileptogenic zone (EZ) in patients undergoing intracranial EEG recordings. Different computer-based signal analysis methods have thus been developed for objectively quantifying ictal FA. Whether these methods detect FA in all forms of focal epilepsies, whether they provide similar information than visual analysis (VA), and whether they might help for the surgical decision remain crucial issues. We thus conducted a retrospective study in 21 consecutive patients suffering from drug-resistant seizures studied by SEEG recordings. Ictal FA were quantified using the Epileptogenicity Maps (EM) method that we recently developed and which generates, by adopting a neuroimaging approach, statistical parametric maps of FA ranging from 60 to 100 Hz (FA 60−100). Ictal FA were analyzed blindly using VA and EM, and the prognostic significance of removing areas exhibiting FA 60−100 at seizure onset was evaluated. A significant ictal FA 60−100 activation was found in all patients, and in 92.6% of all the 68 seizures recorded, whatever the epilepsy type. The overlap ratio (OR) between VA and EM was significantly better for defining the regions spared at seizure onset than those from which seizure arose (p < 0.001), especially in temporal or temporal "plus" epilepsies. EM and VA were much more discordant to define the EZ, with a mean number of electrode contacts involved at seizure onset significantly higher with EM than with VA (p = <0.0001). Seizure outcome correlated with the resection ratio for FA 60−100 , which was significantly higher in seizure-free (Engel's class Ia) than in non seizure-free patients (class Ic-IV) (p = 0.048). The quantification of FA at seizure onset can bring information additional to clinical expertise that might contribute to define accurately the cortical region to be resected

The link between structural connectivity and neurocognition illustrated by focal epilepsy

International audience– Increasing attention is being paid to the assessment of white matter properties and its structural connectivity, both in healthy subjects and patients with cerebral lesions. Within this framework, new neurocogni-tive models based on hodological properties have been developed under a connectomic perspective in order to explain substrates and cognitive mechanisms related to cerebral functions such as language and memory. With regards to focal and drug-resistant epilepsy conceived as a network disorder , new insights in terms of structural connectivity have led to significant advances in epilepsy research, concerning fundamental research (neu-rocognitive mechanisms of plasticity) and clinical application (optimization of decision making for curative surgery). We believe that such findings in the literature, focused on the role of white matter in cerebral functioning in relation to neurocognition, may be helpful for both researchers and clinicians working in the field of epilepsy. Structural connectivity and neurocognition: general information Structural connectivity refers to the study of the anatomical features of brain networks in terms of subcorti-cal white matter (WM) that underlies interconnections between different cortical regions. Within the current context of growing interest with a connectomic perspective, many MRI methods and parameters are now available to assess WM anatomical properties including architecture, spatial trajectory, density or integrity (Sporns, 2013). These structural properties, investigated in relation to cognitive functions and behavioral performance, allows the development of mor

Noise annoyance in urban children: a cross-sectional population-based study

International audienceAcoustical and non-acoustical factors influencing noise annoyance in adults have been well-documented in recent years; however, similar knowledge is lacking in children. The aim of this study was to quantify the annoyance caused by chronic ambient noise at home in children and to assess the relationship between these children0s noise annoyance level and individual and contextual factors in the surrounding urban area. A cross sectional population-based study was conducted including 517 children attending primary school in a European city. Noise annoyance was measured using a self-report questionnaire adapted for children. Six noise exposure level indicators were built at different locations at increasing distances from the child0s bedroom window using a validated strategic noise map. Multilevel logistic models were constructed to investigate factors associated with noise annoyance in children. Noise indicators in front of the child0s bedroom (p 0.01), family residential satisfaction (p 0.03) and socioeconomic characteristics of the individuals and theirneighbourhood (p 0.05) remained associated with child annoyance. These findings illustrate the complex relationships between our environment, how we may perceive it, social factors and health. Better understanding of these relationships will undoubtedly allow us to more effectively quantify the actual effect of noise on human health

Connectivité Fonctionnelle du Langage et de la Mémoire comme Biomarqueur Cognitif dans l'Epilepsie du Lobe Temporal : Résultats Préliminaires

International audienceDrug-resistant temporal lobe epilepsy (TLE) is a severe neurological condition that causes brain injury due to the recurrence of epileptic seizures, with mostly language (L) and memory (M) impairments. Our research aims to: (i) specify the properties of functional modifications on a language and memory network (LMN), according to the hemispheric lateralization of the epileptogenic zone (LH/RH); (ii) evaluate the efficiency of the LMN reorganizations in terms of functional connectivity (FC). Using MRI (3T Philips) we performed resting state fMRI to assess FC. 17 TLE (n=8 Left TLE; n=9 Right TLE) and a group of 28 healthy subjects were included. Two types of FC analyzes have been carried out on the LMN: ROI-to-ROI (pairwise correlations) and graph theory (integration: Eglob, Enod; segregation: Eloc) with Conn toolbox (Whitfield-Gabrieli & Nieto-Castanon, 2012). Spearman correlations were then made between FC biomarkers and LM standardized performance (verbal comprehension index, auditory memory index, naming, verbal fluency). Our main results revealed that: (a) LMN FC is extensively modified in LTLE patients (temporo-frontal and bilateral), compared to RTLE (posterior-right) and healthy; (b) the type of FC modifications depend on the cognitive function (mainly segregation for language and integration for memory); (c) FC parameters correlate remarkably with cognitive scores; (d) hyperconnectivity (increased functional integration capacity) of certain brain regions is not necessarily efficient and can negatively correlate to LM performance (negative plasticity). Thus, we wish to extend the concept of connectome to “cognitome” that taking into account the behavioral consequences of the changes observed in term of connectivity