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Sample records for assimilating seizure dynamics

  1. Assimilating seizure dynamics.

    Directory of Open Access Journals (Sweden)

    Ghanim Ullah

    2010-05-01

    Full Text Available Observability of a dynamical system requires an understanding of its state-the collective values of its variables. However, existing techniques are too limited to measure all but a small fraction of the physical variables and parameters of neuronal networks. We constructed models of the biophysical properties of neuronal membrane, synaptic, and microenvironment dynamics, and incorporated them into a model-based predictor-controller framework from modern control theory. We demonstrate that it is now possible to meaningfully estimate the dynamics of small neuronal networks using as few as a single measured variable. Specifically, we assimilate noisy membrane potential measurements from individual hippocampal neurons to reconstruct the dynamics of networks of these cells, their extracellular microenvironment, and the activities of different neuronal types during seizures. We use reconstruction to account for unmeasured parts of the neuronal system, relating micro-domain metabolic processes to cellular excitability, and validate the reconstruction of cellular dynamical interactions against actual measurements. Data assimilation, the fusing of measurement with computational models, has significant potential to improve the way we observe and understand brain dynamics.

  2. Dynamics of absence seizures

    Science.gov (United States)

    Deeba, Farah; Sanz-Leon, Paula; Robinson, Peter

    A neural field model of the corticothalamic system is used to investigate the dynamics of absence seizures in the presence of temporally varying connection strength between the cerebral cortex and thalamus. Variation of connection strength from cortex to thalamus drives the system into seizure once a threshold is passed and a supercritical Hopf bifurcation occurs. The dynamics and spectral characteristics of the resulting seizures are explored as functions of maximum connection strength, time above threshold, and ramp rate. The results enable spectral and temporal characteristics of seizures to be related to underlying physiological variations via nonlinear dynamics and neural field theory. Notably, this analysis adds to neural field modeling of a wide variety of brain activity phenomena and measurements in recent years. Australian Research Council Grants FL1401000225 and CE140100007.

  3. Assimilation Dynamic Network (ADN) Project

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    National Aeronautics and Space Administration — The Assimilation Dynamic Network (ADN) is a dynamic inter-processor communication network that spans heterogeneous processor architectures, unifying components,...

  4. Ion dynamics during seizures

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    Joseph Valentino Raimondo

    2015-10-01

    Full Text Available Changes in membrane voltage brought about by ion fluxes through voltage and transmitter-gated channels represent the basis of neural activity. As such, electrochemical gradients across the membrane determine the direction and driving force for the flow of ions and are therefore crucial in setting the properties of synaptic transmission and signal propagation. Ion concentration gradients are established by a variety of mechanisms, including specialised transporter proteins. However, transmembrane gradients can be affected by ionic fluxes through channels during periods of elevated neural activity, which in turn are predicted to influence the properties of on-going synaptic transmission. Such activity-induced changes to ion concentration gradients are a feature of both physiological and pathological neural processes. An epileptic seizure is an example of severely perturbed neural activity, which is accompanied by pronounced changes in intracellular and extracellular ion concentrations. Appreciating the factors that contribute to these ion dynamics is critical if we are to understand how a seizure event evolves and is sustained and terminated by neural tissue. Indeed, this issue is of significant clinical importance as status epilepticus – a type of seizure that does not stop of its own accord – is a life-threatening medical emergency. In this review we explore how the transmembrane concentration gradient of the six major ions (K+, Na+, Cl-, Ca2+, H+ and HCO3- is altered during an epileptic seizure. We will first examine each ion individually, before describing how multiple interacting mechanisms between ions might contribute to concentration changes and whether these act to prolong or terminate epileptic activity. In doing so, we will consider how the availability of experimental techniques has both advanced and restricted our ability to study these phenomena.

  5. On the nature of seizure dynamics

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    Stacey, William C.; Quilichini, Pascale P.; Ivanov, Anton I.

    2014-01-01

    Seizures can occur spontaneously and in a recurrent manner, which defines epilepsy; or they can be induced in a normal brain under a variety of conditions in most neuronal networks and species from flies to humans. Such universality raises the possibility that invariant properties exist that characterize seizures under different physiological and pathological conditions. Here, we analysed seizure dynamics mathematically and established a taxonomy of seizures based on first principles. For the predominant seizure class we developed a generic model called Epileptor. As an experimental model system, we used ictal-like discharges induced in vitro in mouse hippocampi. We show that only five state variables linked by integral-differential equations are sufficient to describe the onset, time course and offset of ictal-like discharges as well as their recurrence. Two state variables are responsible for generating rapid discharges (fast time scale), two for spike and wave events (intermediate time scale) and one for the control of time course, including the alternation between ‘normal’ and ictal periods (slow time scale). We propose that normal and ictal activities coexist: a separatrix acts as a barrier (or seizure threshold) between these states. Seizure onset is reached upon the collision of normal brain trajectories with the separatrix. We show theoretically and experimentally how a system can be pushed toward seizure under a wide variety of conditions. Within our experimental model, the onset and offset of ictal-like discharges are well-defined mathematical events: a saddle-node and homoclinic bifurcation, respectively. These bifurcations necessitate a baseline shift at onset and a logarithmic scaling of interspike intervals at offset. These predictions were not only confirmed in our in vitro experiments, but also for focal seizures recorded in different syndromes, brain regions and species (humans and zebrafish). Finally, we identified several possible biophysical

  6. Scalable and balanced dynamic hybrid data assimilation

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    Kauranne, Tuomo; Amour, Idrissa; Gunia, Martin; Kallio, Kari; Lepistö, Ahti; Koponen, Sampsa

    2017-04-01

    Scalability of complex weather forecasting suites is dependent on the technical tools available for implementing highly parallel computational kernels, but to an equally large extent also on the dependence patterns between various components of the suite, such as observation processing, data assimilation and the forecast model. Scalability is a particular challenge for 4D variational assimilation methods that necessarily couple the forecast model into the assimilation process and subject this combination to an inherently serial quasi-Newton minimization process. Ensemble based assimilation methods are naturally more parallel, but large models force ensemble sizes to be small and that results in poor assimilation accuracy, somewhat akin to shooting with a shotgun in a million-dimensional space. The Variational Ensemble Kalman Filter (VEnKF) is an ensemble method that can attain the accuracy of 4D variational data assimilation with a small ensemble size. It achieves this by processing a Gaussian approximation of the current error covariance distribution, instead of a set of ensemble members, analogously to the Extended Kalman Filter EKF. Ensemble members are re-sampled every time a new set of observations is processed from a new approximation of that Gaussian distribution which makes VEnKF a dynamic assimilation method. After this a smoothing step is applied that turns VEnKF into a dynamic Variational Ensemble Kalman Smoother VEnKS. In this smoothing step, the same process is iterated with frequent re-sampling of the ensemble but now using past iterations as surrogate observations until the end result is a smooth and balanced model trajectory. In principle, VEnKF could suffer from similar scalability issues as 4D-Var. However, this can be avoided by isolating the forecast model completely from the minimization process by implementing the latter as a wrapper code whose only link to the model is calling for many parallel and totally independent model runs, all of them

  7. Plasticity-modulated seizure dynamics for seizure termination in realistic neuronal models

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    Koppert, M.M.J.; Kalitzin, S.; Lopes da Silva, F.H.; Viergever, M.A.

    2011-01-01

    In previous studies we showed that autonomous absence seizure generation and termination can be explained by realistic neuronal models eliciting bi-stable dynamics. In these models epileptic seizures are triggered either by external stimuli (reflex epilepsies) or by internal fluctuations. This

  8. Hungry Neurons: Metabolic Insights on Seizure Dynamics

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    Paolo Bazzigaluppi

    2017-10-01

    Full Text Available Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dysfunction and extracellular ionic species (dysregulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilization of seizures pathophysiology revealing (in most cases reduced metabolism in the inter-ictal period and increased metabolism in the seconds preceding and during the appearance of seizures. In the present review, we summarize the clinical and preclinical observations showing metabolic dysregulation during epileptogenesis, seizure initiation, and termination, and in the inter-ictal period. Recent preclinical studies have shown that 2-Deoxyglucose (2-DG, a glycolysis blocker is a novel therapeutic approach to reduce seizures. Furthermore, we present initial evidence for the effectiveness of 2-DG in arresting 4-Aminopyridine induced neocortical seizures in vivo in the mouse.

  9. A novel dynamic update framework for epileptic seizure prediction.

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    Han, Min; Ge, Sunan; Wang, Minghui; Hong, Xiaojun; Han, Jie

    2014-01-01

    Epileptic seizure prediction is a difficult problem in clinical applications, and it has the potential to significantly improve the patients' daily lives whose seizures cannot be controlled by either drugs or surgery. However, most current studies of epileptic seizure prediction focus on high sensitivity and low false-positive rate only and lack the flexibility for a variety of epileptic seizures and patients' physical conditions. Therefore, a novel dynamic update framework for epileptic seizure prediction is proposed in this paper. In this framework, two basic sample pools are constructed and updated dynamically. Furthermore, the prediction model can be updated to be the most appropriate one for the prediction of seizures' arrival. Mahalanobis distance is introduced in this part to solve the problem of side information, measuring the distance between two data sets. In addition, a multichannel feature extraction method based on Hilbert-Huang transform and extreme learning machine is utilized to extract the features of a patient's preseizure state against the normal state. At last, a dynamic update epileptic seizure prediction system is built up. Simulations on Freiburg database show that the proposed system has a better performance than the one without update. The research of this paper is significantly helpful for clinical applications, especially for the exploitation of online portable devices.

  10. Human seizures couple across spatial scales through travelling wave dynamics

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    Martinet, L.-E.; Fiddyment, G.; Madsen, J. R.; Eskandar, E. N.; Truccolo, W.; Eden, U. T.; Cash, S. S.; Kramer, M. A.

    2017-04-01

    Epilepsy--the propensity toward recurrent, unprovoked seizures--is a devastating disease affecting 65 million people worldwide. Understanding and treating this disease remains a challenge, as seizures manifest through mechanisms and features that span spatial and temporal scales. Here we address this challenge through the analysis and modelling of human brain voltage activity recorded simultaneously across microscopic and macroscopic spatial scales. We show that during seizure large-scale neural populations spanning centimetres of cortex coordinate with small neural groups spanning cortical columns, and provide evidence that rapidly propagating waves of activity underlie this increased inter-scale coupling. We develop a corresponding computational model to propose specific mechanisms--namely, the effects of an increased extracellular potassium concentration diffusing in space--that support the observed spatiotemporal dynamics. Understanding the multi-scale, spatiotemporal dynamics of human seizures--and connecting these dynamics to specific biological mechanisms--promises new insights to treat this devastating disease.

  11. A Novel Dynamic Update Framework for Epileptic Seizure Prediction

    Directory of Open Access Journals (Sweden)

    Min Han

    2014-01-01

    Full Text Available Epileptic seizure prediction is a difficult problem in clinical applications, and it has the potential to significantly improve the patients’ daily lives whose seizures cannot be controlled by either drugs or surgery. However, most current studies of epileptic seizure prediction focus on high sensitivity and low false-positive rate only and lack the flexibility for a variety of epileptic seizures and patients’ physical conditions. Therefore, a novel dynamic update framework for epileptic seizure prediction is proposed in this paper. In this framework, two basic sample pools are constructed and updated dynamically. Furthermore, the prediction model can be updated to be the most appropriate one for the prediction of seizures’ arrival. Mahalanobis distance is introduced in this part to solve the problem of side information, measuring the distance between two data sets. In addition, a multichannel feature extraction method based on Hilbert-Huang transform and extreme learning machine is utilized to extract the features of a patient’s preseizure state against the normal state. At last, a dynamic update epileptic seizure prediction system is built up. Simulations on Freiburg database show that the proposed system has a better performance than the one without update. The research of this paper is significantly helpful for clinical applications, especially for the exploitation of online portable devices.

  12. Dynamics of muscle activation during tonic-clonic seizures.

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    Conradsen, Isa; Moldovan, Mihai; Jennum, Poul; Wolf, Peter; Farina, Dario; Beniczky, Sándor

    2013-03-01

    The purpose of our study was to elucidate the dynamics of muscle activation during generalised tonic-clonic seizures (GTCS). We recorded surface electromyography (EMG) from the deltoid muscle during 26 GTCS from 13 patients and compared it with GTCS-like events acted by 10 control subjects. GTCS consisted of a sequence of phases best described quantitatively by dynamics of the low frequency (LF) wavelet component (2-8Hz). Contrary to the traditional view, the tonic phase started with a gradual increase in muscle activity. A longer clonic phase was associated with a shorter onset of the tonic phase and a higher seizure occurrence. Increase in LF occurred during the onset phase and during the transition from the tonic to the clonic phase, corresponding to the vibratory movements. The clonic phase consisted of EMG discharges of remarkably constant duration (0.2s) separated by silent periods (SP) of exponentially increasing duration - features that could not be reproduced voluntarily. The last SP was longer in seizures with higher EMG peak frequency whereas the energy of the last clonus was higher in seizures with a short clonic phase. We found specific features of muscle activation dynamics during GTCS. Our findings suggest that the same inhibitory mechanisms that contribute to GTCS termination counteract seizure initiation, accounting for the gradual onset. Both active inhibition and mechanisms related to metabolic depletion act synergistically to stop the seizure. Analysis of the ictal EMG dynamics is a valuable tool for monitoring the balance between pro-convulsive and anti-convulsive factors. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Dynamics of muscle activation during tonic-clonic seizures

    DEFF Research Database (Denmark)

    Conradsen, Isa; Moldovan, Mihai; Jennum, Poul

    2013-01-01

    The purpose of our study was to elucidate the dynamics of muscle activation during generalised tonic-clonic seizures (GTCS). We recorded surface electromyography (EMG) from the deltoid muscle during 26 GTCS from 13 patients and compared it with GTCS-like events acted by 10 control subjects. GTCS...... consisted of a sequence of phases best described quantitatively by dynamics of the low frequency (LF) wavelet component (2-8Hz). Contrary to the traditional view, the tonic phase started with a gradual increase in muscle activity. A longer clonic phase was associated with a shorter onset of the tonic phase...... and a higher seizure occurrence. Increase in LF occurred during the onset phase and during the transition from the tonic to the clonic phase, corresponding to the vibratory movements. The clonic phase consisted of EMG discharges of remarkably constant duration (0.2s) separated by silent periods (SP...

  14. Towards a Comprehensive Dynamic-chemistry Assimilation for Eos-Chem: Plans and Status in NASA's Data Assimilation Office

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    Pawson, Steven; Lin, Shian-Jiann; Rood, Richard B.; Stajner, Ivanka; Nebuda, Sharon; Nielsen, J. Eric; Douglass, Anne R.

    2000-01-01

    In order to support the EOS-Chem project, a comprehensive assimilation package for the coupled chemical-dynamical system is being developed by the Data Assimilation Office at NASA GSFC. This involves development of a coupled chemistry/meteorology model and of data assimilation techniques for trace species and meteorology. The model is being developed using the flux-form semi-Lagrangian dynamical core of Lin and Rood, the physical parameterizations from the NCAR Community Climate Model, and atmospheric chemistry modules from the Atmospheric Chemistry and Dynamics branch at NASA GSFC. To date the following results have been obtained: (i) multi-annual simulations with the dynamics-radiation model show the credibility of the package for atmospheric simulations; (ii) initial simulations including a limited number of middle atmospheric trace gases reveal the realistic nature of transport mechanisms, although there is still a need for some improvements. Samples of these results will be shown. A meteorological assimilation system is currently being constructed using the model; this will form the basis for the proposed meteorological/chemical assimilation package. The latter part of the presentation will focus on areas targeted for development in the near and far terms, with the objective of Providing a comprehensive assimilation package for the EOS-Chem science experiment. The first stage will target ozone assimilation. The plans also encompass a reanalysis (ReSTS) for the 1991-1995 period, which includes the Mt. Pinatubo eruption and the time when a large number of UARS observations were available. One of the most challenging aspects of future developments will be to couple theoretical advances in tracer assimilation with the practical considerations of a real environment and eventually a near-real-time assimilation system.

  15. Transition dynamics of generalized multiple epileptic seizures associated with thalamic reticular nucleus excitability: A computational study

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    Liu, Suyu; Wang, Qingyun

    2017-11-01

    Presently, we improve a computational framework of thalamocortical circuits related to the Taylor's model to investigate the relationship between thalamic reticular nucleus (RE) excitability and epilepsy. By using bifurcation analysis, we explore the RE's excitability dynamics mechanism in the processes of seizure generation, development and transition. Results show that the seizure-free state, absence seizures, clonic seizures and tonic seizures can be formed as the RE excitability is changed in this established model. Importantly, it is verified that physiological changing GABAA inhibition in RE can elicit absence seizures and clonic seizures and the pathological transitions between these two seizures. Furthermore, when the level of AMPA connection is decreased or increased, this proposed model embraces absence seizures and clonic seizures, and tonic seizures, respectively. Except that, bifurcation mechanisms of dynamical transition of different seizures are analyzed in detail. In addition, hybrid regulations of the reticular nucleus excitability for epileptic seizures are proven to be valid within the suitable levels of AMPA and GABAA connection. Hopefully, the obtained results could be helpful for effective control of epileptic activities with additional pharmacological interference.

  16. A study of the dynamics of seizure propagation across micro domains in the vicinity of the seizure onset zone

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    Basu, Ishita; Kudela, Pawel; Korzeniewska, Anna; Franaszczuk, Piotr J.; Anderson, William S.

    2015-08-01

    Objective. The use of micro-electrode arrays to measure electrical activity from the surface of the brain is increasingly being investigated as a means to improve seizure onset zone (SOZ) localization. In this work, we used a multivariate autoregressive model to determine the evolution of seizure dynamics in the 70-110 Hz high frequency band across micro-domains sampled by such micro-electrode arrays. We showed that a directed transfer function (DTF) can be used to estimate the flow of seizure activity in a set of simulated micro-electrode data with known propagation pattern. Approach. We used seven complex partial seizures recorded from four patients undergoing intracranial monitoring for surgical evaluation to reconstruct the seizure propagation pattern over sliding windows using a DTF measure. Main results. We showed that a DTF can be used to estimate the flow of seizure activity in a set of simulated micro-electrode data with a known propagation pattern. In general, depending on the location of the micro-electrode grid with respect to the clinical SOZ and the time from seizure onset, ictal propagation changed in directional characteristics over a 2-10 s time scale, with gross directionality limited to spatial dimensions of approximately 9 m{{m}2}. It was also seen that the strongest seizure patterns in the high frequency band and their sources over such micro-domains are more stable over time and across seizures bordering the clinically determined SOZ than inside. Significance. This type of propagation analysis might in future provide an additional tool to epileptologists for characterizing epileptogenic tissue. This will potentially help narrowing down resection zones without compromising essential brain functions as well as provide important information about targeting anti-epileptic stimulation devices.

  17. Network dynamics of the brain and influence of the epileptic seizure onset zone

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    Burns, Samuel P.; Santaniello, Sabato; Yaffe, Robert B.; Jouny, Christophe C.; Crone, Nathan E.; Bergey, Gregory K.; Anderson, William S.; Sarma, Sridevi V.

    2014-01-01

    The human brain is a dynamic networked system. Patients with partial epileptic seizures have focal regions that periodically diverge from normal brain network dynamics during seizures. We studied the evolution of brain connectivity before, during, and after seizures with graph-theoretic techniques on continuous electrocorticographic (ECoG) recordings (5.4 ± 1.7 d per patient, mean ± SD) from 12 patients with temporal, occipital, or frontal lobe partial onset seizures. Each electrode was considered a node in a graph, and edges between pairs of nodes were weighted by their coherence within a frequency band. The leading eigenvector of the connectivity matrix, which captures network structure, was tracked over time and clustered to uncover a finite set of brain network states. Across patients, we found that (i) the network connectivity is structured and defines a finite set of brain states, (ii) seizures are characterized by a consistent sequence of states, (iii) a subset of nodes is isolated from the network at seizure onset and becomes more connected with the network toward seizure termination, and (iv) the isolated nodes may identify the seizure onset zone with high specificity and sensitivity. To localize a seizure, clinicians visually inspect seizures recorded from multiple intracranial electrode contacts, a time-consuming process that may not always result in definitive localization. We show that network metrics computed from all ECoG channels capture the dynamics of the seizure onset zone as it diverges from normal overall network structure. This suggests that a state space model can be used to help localize the seizure onset zone in ECoG recordings. PMID:25404339

  18. Network dynamics of the brain and influence of the epileptic seizure onset zone.

    Science.gov (United States)

    Burns, Samuel P; Santaniello, Sabato; Yaffe, Robert B; Jouny, Christophe C; Crone, Nathan E; Bergey, Gregory K; Anderson, William S; Sarma, Sridevi V

    2014-12-09

    The human brain is a dynamic networked system. Patients with partial epileptic seizures have focal regions that periodically diverge from normal brain network dynamics during seizures. We studied the evolution of brain connectivity before, during, and after seizures with graph-theoretic techniques on continuous electrocorticographic (ECoG) recordings (5.4 ± 1.7 d per patient, mean ± SD) from 12 patients with temporal, occipital, or frontal lobe partial onset seizures. Each electrode was considered a node in a graph, and edges between pairs of nodes were weighted by their coherence within a frequency band. The leading eigenvector of the connectivity matrix, which captures network structure, was tracked over time and clustered to uncover a finite set of brain network states. Across patients, we found that (i) the network connectivity is structured and defines a finite set of brain states, (ii) seizures are characterized by a consistent sequence of states, (iii) a subset of nodes is isolated from the network at seizure onset and becomes more connected with the network toward seizure termination, and (iv) the isolated nodes may identify the seizure onset zone with high specificity and sensitivity. To localize a seizure, clinicians visually inspect seizures recorded from multiple intracranial electrode contacts, a time-consuming process that may not always result in definitive localization. We show that network metrics computed from all ECoG channels capture the dynamics of the seizure onset zone as it diverges from normal overall network structure. This suggests that a state space model can be used to help localize the seizure onset zone in ECoG recordings.

  19. Dynamics of convulsive seizure termination and postictal generalized EEG suppression

    NARCIS (Netherlands)

    Bauer, P.R.; Thijs, R.D.; Lamberts, R.J.; Velis, D.N.; Visser, G.H.; Tolner, E.A.; Sander, J.W.; Lopes da Silva, F.H.; Kalitzin, S.N.

    It is not fully understood how seizures terminate and why some seizures are followed by a period of complete brain activity suppression, postictal generalized EEG suppression. This is clinically relevant as there is a potential association between postictal generalized EEG suppression,

  20. Dynamic Network Drivers of Seizure Generation, Propagation and Termination in Human Neocortical Epilepsy

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    Khambhati, Ankit N.; Davis, Kathryn A.; Oommen, Brian S.; Chen, Stephanie H.; Lucas, Timothy H.; Litt, Brian; Bassett, Danielle S.

    2015-01-01

    The epileptic network is characterized by pathologic, seizure-generating ‘foci’ embedded in a web of structural and functional connections. Clinically, seizure foci are considered optimal targets for surgery. However, poor surgical outcome suggests a complex relationship between foci and the surrounding network that drives seizure dynamics. We developed a novel technique to objectively track seizure states from dynamic functional networks constructed from intracranial recordings. Each dynamical state captures unique patterns of network connections that indicate synchronized and desynchronized hubs of neural populations. Our approach suggests that seizures are generated when synchronous relationships near foci work in tandem with rapidly changing desynchronous relationships from the surrounding epileptic network. As seizures progress, topographical and geometrical changes in network connectivity strengthen and tighten synchronous connectivity near foci—a mechanism that may aid seizure termination. Collectively, our observations implicate distributed cortical structures in seizure generation, propagation and termination, and may have practical significance in determining which circuits to modulate with implantable devices. PMID:26680762

  1. Dynamical analogy between epileptic seizures and seismogenic electromagnetic emissions by means of nonextensive statistical mechanics

    CERN Document Server

    Eftaxias, Konstantinos; Potirakis, Stelios M; Balasis, George

    2012-01-01

    The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Several authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks. Recently, authors have shown that a dynamical analogy supported by scale-free statistics exists between seizures and earthquakes, analysing populations of different seizures and earthquakes, respectively. The purpose of this paper is to suggest a shift in emphasis from the large to the small scale: our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. We apply the concepts of the nonextensive statistical physics to support the suggestion that a dynamical analogy exists between the tw...

  2. From cognitive networks to seizures: Stimulus evoked dynamics in a coupled cortical network

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    Lee, Jaejin; Ermentrout, Bard; Bodner, Mark

    2013-12-01

    Epilepsy is one of the most common neuropathologies worldwide. Seizures arising in epilepsy or in seizure disorders are characterized generally by uncontrolled spread of excitation and electrical activity to a limited region or even over the entire cortex. While it is generally accepted that abnormal excessive firing and synchronization of neuron populations lead to seizures, little is known about the precise mechanisms underlying human epileptic seizures, the mechanisms of transitions from normal to paroxysmal activity, or about how seizures spread. Further complication arises in that seizures do not occur with a single type of dynamics but as many different phenotypes and genotypes with a range of patterns, synchronous oscillations, and time courses. The concept of preventing, terminating, or modulating seizures and/or paroxysmal activity through stimulation of brain has also received considerable attention. The ability of such stimulation to prevent or modulate such pathological activity may depend on identifiable parameters. In this work, firing rate networks with inhibitory and excitatory populations were modeled. Network parameters were chosen to model normal working memory behaviors. Two different models of cognitive activity were developed. The first model consists of a single network corresponding to a local area of the brain. The second incorporates two networks connected through sparser recurrent excitatory connectivity with transmission delays ranging from approximately 3 ms within local populations to 15 ms between populations residing in different cortical areas. The effect of excitatory stimulation to activate working memory behavior through selective persistent activation of populations is examined in the models, and the conditions and transition mechanisms through which that selective activation breaks down producing spreading paroxysmal activity and seizure states are characterized. Specifically, we determine critical parameters and architectural

  3. Dynamical analogy between epileptic seizures and seismogenic electromagnetic emissions by means of nonextensive statistical mechanics

    Science.gov (United States)

    Eftaxias, Konstantinos; Minadakis, George; Potirakis, Stelios. M.; Balasis, Georgios

    2013-02-01

    The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Several authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks. Recently, authors have shown that a dynamical analogy supported by scale-free statistics exists between seizures and earthquakes, analyzing populations of different seizures and earthquakes, respectively. The purpose of this paper is to suggest a shift in emphasis from the large to the small scale: our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. We apply the concepts of the nonextensive statistical physics to support the suggestion that a dynamical analogy exists between the two different extreme events, seizures and earthquakes. We also investigate the existence of such an analogy by means of scale-free statistics (the Gutenberg-Richter distribution of event sizes and the distribution of the waiting time until the next event). The performed analysis confirms the existence of a dynamic analogy between earthquakes and seizures, which moreover follow the dynamics of magnetic storms and solar flares.

  4. Potential of an ensemble Kalman smoother for stratospheric chemical-dynamical data assimilation

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    Thomas Milewski

    2013-02-01

    Full Text Available A new stratospheric ensemble Kalman smoother (EnKS system is introduced, and the potential of assimilating posterior stratospheric observations to better constrain the whole model state at analysis time is investigated. A set of idealised perfect-model Observation System Simulation Experiments (OSSE assimilating synthetic limb-sounding temperature or ozone retrievals are performed with a chemistry–climate model. The impact during the analysis step is characterised in terms of the root mean square error reduction between the forecast state and the analysis state. The performances of (1 a fixed-lag EnKS assimilating observations spread over 48 hours and (2 an ensemble Kalman Filter (EnKF assimilating a denser network of observations are compared with a reference EnKF. The ozone assimilation with EnKS shows a significant additional reduction of analysis error of the order of 10% for dynamical and chemical variables in the extratropical upper troposphere lower stratosphere (UTLS and Polar Vortex regions when compared to the reference EnKF. This reduction has similar magnitude to the one achieved by the denser-network EnKF assimilation. Similarly, the temperature assimilation with EnKS significantly decreases the error in the UTLS for the wind variables like the denser-network EnKF assimilation. However, the temperature assimilation with EnKS has little or no significant impact on the temperature and ozone analyses, whereas the denser-network EnKF shows improvement with respect to the reference EnKF. The different analysis impacts from the assimilation of current and posterior ozone observations indicate the capacity of time-lagged background-error covariances to represent temporal interactions up to 48 hours between variables during the ensemble data assimilation analysis step, and the possibility to use posterior observations whenever additional current observations are unavailable. The possible application of the EnKS for reanalyses is

  5. Opinion Dynamics with Heterogeneous Interactions and Information Assimilation

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    Mir Tabatabaei, Seydeh Anahita

    2013-01-01

    In any modern society, individuals interact to form opinions on various topics, including economic, political, and social aspects. Opinions evolve as the result of the continuous exchange of information among individuals and of the assimilation of information distributed by media. The impact of individuals' opinions on each other forms a network,…

  6. Mathematical modeling of encephalogram dynamics during epileptic seizure

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    Sysoeva, M. V.; Sysoev, I. V.

    2012-02-01

    The problem of constructing a compact mathematical model representing various fragments of electroencephalograms (EEGs) during epileptic absence seizures is considered. Such a model would be useful for solving a number of practical tasks related to the clustering of time series, seeking for relationships between various leads, separating norm and pathology, etc. It is shown that an adequate model that takes into account the EEG structure can be constructed using nonuniform embedding. The dimensionality, degree of nonlinearity, and lags are selected based on an objective numerical criterion.

  7. An evaluation of spindle-shaft seizure accident sequences for the Schenck Dynamic Balancer

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    Bott, T.F.; Fischer, S.R.

    1998-11-01

    This study was conducted at the request of the USDOE/AL Dynamic Balancer Project Team to develop a set of representative accident sequences initiated by rapid seizure of the spindle shaft of the Schenck dynamic balancing machine used in the mass properties testing activities in Bay 12-60 at the Pantex Plant. This Balancer is used for balancing reentry vehicles. In addition, the study identified potential causes of possible spindle-shaft seizure leading to a rapid deceleration of the rotating assembly. These accident sequences extend to the point that the reentry vehicle either remains in stable condition on the balancing machine or leaves the machine with some translational and rotational motion. Fault-tree analysis was used to identify possible causes of spindle-shaft seizure, and failure modes and effects analysis identified the results of shearing of different machine components. Cause-consequence diagrams were used to help develop accident sequences resulting from the possible effects of spindle-shaft seizure. To make these accident sequences physically reasonable, the analysts used idealized models of the dynamics of rotating masses. Idealized physical modeling also was used to provide approximate values of accident parameters that lead to branching down different accident progression paths. The exacerbating conditions of balancing machine over-speed and improper assembly of the fixture to the face plate are also addressed.

  8. Reconstructing neural dynamics using data assimilation with multiple models

    Science.gov (United States)

    Hamilton, Franz; Cressman, John; Peixoto, Nathalia; Sauer, Timothy

    2014-09-01

    Assimilation of data with models of physical processes is a critical component of modern scientific analysis. In recent years, nonlinear versions of Kalman filtering have been developed, in addition to methods that estimate model parameters in parallel with the system state. We propose a substantial extension of these tools to deal with the specific case of unmodeled variables, when training data from the variable is avaiable. The method uses a stack of several, nonidentical copies of a physical model to jointly reconstruct the variable in question. We demonstrate the ability of this technique to accurately recover an unmodeled experimental quantity, such as an ion concentration, from a single voltage trace after the training period is completed. The method is applied to reconstruct the potassium concentration in a neural culture from multielectrode array voltage measurements.

  9. Dynamic Responses of the Earth's Outer Core to Assimilation of Observed Geomagnetic Secular Variation

    Science.gov (United States)

    Kuang, Weijia; Tangborn, Andrew

    2014-01-01

    Assimilation of surface geomagnetic observations and geodynamo models has advanced very quickly in recent years. However, compared to advanced data assimilation systems in meteorology, geomagnetic data assimilation (GDAS) is still in an early stage. Among many challenges ranging from data to models is the disparity between the short observation records and the long time scales of the core dynamics. To better utilize available observational information, we have made an effort in this study to directly assimilate the Gauss coefficients of both the core field and its secular variation (SV) obtained via global geomagnetic field modeling, aiming at understanding the dynamical responses of the core fluid to these additional observational constraints. Our studies show that the SV assimilation helps significantly to shorten the dynamo model spin-up process. The flow beneath the core-mantle boundary (CMB) responds significantly to the observed field and its SV. The strongest responses occur in the relatively small scale flow (of the degrees L is approx. 30 in spherical harmonic expansions). This part of the flow includes the axisymmetric toroidal flow (of order m = 0) and non-axisymmetric poloidal flow with m (is) greater than 5. These responses can be used to better understand the core flow and, in particular, to improve accuracies of predicting geomagnetic variability in future.

  10. A data assimilation tool for the Pagasitikos Gulf ecosystem dynamics: Methods and benefits

    KAUST Repository

    Korres, Gerasimos

    2012-06-01

    Within the framework of the European INSEA project, an advanced assimilation system has been implemented for the Pagasitikos Gulf ecosystem. The system is based on a multivariate sequential data assimilation scheme that combines satellite ocean sea color (chlorophyll-a) data with the predictions of a three-dimensional coupled physical-biochemical model of the Pagasitikos Gulf ecosystem presented in a companion paper. The hydrodynamics are solved with a very high resolution (1/100°) implementation of the Princeton Ocean Model (POM). This model is nested within a coarser resolution model of the Aegean Sea which is part of the Greek POSEIDON forecasting system. The forecast of the Aegean Sea model, itself nested and initialized from a Mediterranean implementation of POM, is also used to periodically re-initalize the Pagatisikos hydrodynamics model using variational initialization techniques. The ecosystem dynamics of Pagasitikos are tackled with a stand-alone implementation of the European Seas Ecosystem Model (ERSEM). The assimilation scheme is based on the Singular Evolutive Extended Kalman (SEEK) filter, in which the error statistics are parameterized by means of a suitable set of Empirical Orthogonal Functions (EOFs).The assimilation experiments were performed for year 2003 and additionally for a 9-month period over 2006 during which the physical model was forced with the POSEIDON-ETA 6-hour atmospheric fields. The assimilation system is validated by assessing the relevance of the system in fitting the data, the impact of the assimilation on non-observed biochemical processes and the overall quality of the forecasts. Assimilation of either GlobColour in 2003 or SeaWiFS in 2006 chlorophyll-a data enhances the identification of the ecological state of the Pagasitikos Gulf. Results, however, suggest that subsurface ecological observations are needed to improve the controllability of the ecosystem in the deep layers. © 2011 Elsevier B.V.

  11. Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach

    Directory of Open Access Journals (Sweden)

    F. I. Pisnitchenko

    2008-11-01

    Full Text Available In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. In this work we formulate the joint problem of finding the regional model solution and data assimilation as a PDE-constrained optimization problem. Three simple model examples (ODE Burgers equation, Rossby-Oboukhov equation, Korteweg-de Vries equation are considered in this paper. Numerical experiments indicate that the optimization approach can significantly improve the precision of the regional solution.

  12. Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach

    Science.gov (United States)

    Pisnitchenko, F. I.; Pisnichenko, I. A.; Martínez, J. M.; Santos, S. A.

    2008-11-01

    In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. In this work we formulate the joint problem of finding the regional model solution and data assimilation as a PDE-constrained optimization problem. Three simple model examples (ODE Burgers equation, Rossby-Oboukhov equation, Korteweg-de Vries equation) are considered in this paper. Numerical experiments indicate that the optimization approach can significantly improve the precision of the regional solution.

  13. Variational assimilation in the coastal ocean model off Oregon: the role of dynamics

    Science.gov (United States)

    Kurapov, A. L.; Egbert, G. D.; Allen, J. S.; Yu, P.

    2010-12-01

    Coastal ocean circulation off Oregon (Northwestern US) is dominated in summer by wind-driven upwelling and strong alongshore shelf currents (in excess of 0.5 m/s). These currents separate from the shelf in the adjacent interior ocean (coastal transition zone, CTZ) where dynamics are more dominated by the nonlinear interactions of jets and eddies than direct wind forcing. To constrain model circulation both over the shelf and in the CTZ and facilitate accurate forecasts, the variational data assimilation system is developed combining the AVRORA adjoint system developed by our group and the nonlinear three-dimensional Regional Ocean Modeling System (ROMS). This system has been utilized in a series of 3- to 6-day time windows. Correction to initial conditions is found at the beginning of each window, using AVRORA. The nonlinear ROMS is started from those initial conditions to obtain improved analysis and forecast (background solution for the next window). Assimilation experiments have been done using satellite alongtrack sea surface height (SSH) altimetry, sea surface temperature (SST) maps (blended multi-satellite products and hourly data from the geostationary GOES satellite), and surface currents from high-frequency radars. To demonstrate the value of the dynamically based time-interpolation in the four-dimensional variational (4DVAR) approach, we compare results assimilating data in 6-day and 1-day time windows (results in the latter case should be closer to the 3DVAR approach). The importance of the dynamics in the adjoint model is revealed when results for the initial correction due to a single observation (a so called representer function) are compared in cases using multivariate-balanced and univariate-unbalanced initial condition error covariances. In the case using the unbalanced covariance with the horizontal decorrelation scale of the dominant ocean features (25-50 km), the representer at the initial time still shows some dominant dynamical balances, since

  14. [Assimilation of problematic experiences: a case study on short-term dynamic psychotherapy].

    Science.gov (United States)

    Meystre, Claudia; Kramer, Ueli; de Roten, Yves; Michel, Luc; Despland, Jean-Nicolas

    2011-01-01

    The assimilation model is a qualitative and integrative approach that enables to study change processes that occur in psychotherapy. According to Stiles, this model conceives the individual's personality as constituent of different voices; the concept of voice is used to describe traces left by past experiences. During the psychotherapy, we can observe the progressive integration of the problematic voices into the patient's personality. We applied the assimilation model to a 34-session-long case of an effective short-term dynamic psychotherapy. We've chosen eight sessions we transcribed and analyzed by establishing points of contact between the case and the theory. The results are presented and discussed in terms of the evolution of the main voices in the patient.

  15. Dynamic imaging of coherent sources reveals different network connectivity underlying the generation and perpetuation of epileptic seizures.

    Directory of Open Access Journals (Sweden)

    Lydia Elshoff

    Full Text Available The concept of focal epilepsies includes a seizure origin in brain regions with hyper synchronous activity (epileptogenic zone and seizure onset zone and a complex epileptic network of different brain areas involved in the generation, propagation, and modulation of seizures. The purpose of this work was to study functional and effective connectivity between regions involved in networks of epileptic seizures. The beginning and middle part of focal seizures from ictal surface EEG data were analyzed using dynamic imaging of coherent sources (DICS, an inverse solution in the frequency domain which describes neuronal networks and coherences of oscillatory brain activities. The information flow (effective connectivity between coherent sources was investigated using the renormalized partial directed coherence (RPDC method. In 8/11 patients, the first and second source of epileptic activity as found by DICS were concordant with the operative resection site; these patients became seizure free after epilepsy surgery. In the remaining 3 patients, the results of DICS / RPDC calculations and the resection site were discordant; these patients had a poorer post-operative outcome. The first sources as found by DICS were located predominantly in cortical structures; subsequent sources included some subcortical structures: thalamus, Nucl. Subthalamicus and cerebellum. DICS seems to be a powerful tool to define the seizure onset zone and the epileptic networks involved. Seizure generation seems to be related to the propagation of epileptic activity from the primary source in the seizure onset zone, and maintenance of seizures is attributed to the perpetuation of epileptic activity between nodes in the epileptic network. Despite of these promising results, this proof of principle study needs further confirmation prior to the use of the described methods in the clinical praxis.

  16. Dynamic Imaging of Coherent Sources Reveals Different Network Connectivity Underlying the Generation and Perpetuation of Epileptic Seizures

    Science.gov (United States)

    Anwar, Abdul Rauf; Deuschl, Günther; Stephani, Ulrich; Raethjen, Jan; Siniatchkin, Michael

    2013-01-01

    The concept of focal epilepsies includes a seizure origin in brain regions with hyper synchronous activity (epileptogenic zone and seizure onset zone) and a complex epileptic network of different brain areas involved in the generation, propagation, and modulation of seizures. The purpose of this work was to study functional and effective connectivity between regions involved in networks of epileptic seizures. The beginning and middle part of focal seizures from ictal surface EEG data were analyzed using dynamic imaging of coherent sources (DICS), an inverse solution in the frequency domain which describes neuronal networks and coherences of oscillatory brain activities. The information flow (effective connectivity) between coherent sources was investigated using the renormalized partial directed coherence (RPDC) method. In 8/11 patients, the first and second source of epileptic activity as found by DICS were concordant with the operative resection site; these patients became seizure free after epilepsy surgery. In the remaining 3 patients, the results of DICS / RPDC calculations and the resection site were discordant; these patients had a poorer post-operative outcome. The first sources as found by DICS were located predominantly in cortical structures; subsequent sources included some subcortical structures: thalamus, Nucl. Subthalamicus and cerebellum. DICS seems to be a powerful tool to define the seizure onset zone and the epileptic networks involved. Seizure generation seems to be related to the propagation of epileptic activity from the primary source in the seizure onset zone, and maintenance of seizures is attributed to the perpetuation of epileptic activity between nodes in the epileptic network. Despite of these promising results, this proof of principle study needs further confirmation prior to the use of the described methods in the clinical praxis. PMID:24194931

  17. Brain network dynamics characterization in epileptic seizures. Joint directed graph and pairwise synchronization measures

    Science.gov (United States)

    Rodrigues, A. C.; Machado, B. S.; Florence, G.; Hamad, A. P.; Sakamoto, A. C.; Fujita, A.; Baccalá, L. A.; Amaro, E.; Sameshima, K.

    2014-12-01

    Here we propose and evaluate a new approach to analyse multichannel mesial temporal lobe epilepsy EEG data from eight patients through complex network and synchronization theories. The method employs a Granger causality test to infer the directed connectivity graphs and a wavelet transform based phase synchronization measure whose characteristics allow studying dynamical transitions during epileptic seizures. We present a new combined graph measure that quantifies the level of network hub formation, called network hub out-degree, which closely reflects the level of synchronization observed during the ictus.

  18. Random Finite Set Based Data Assimilation for Dynamic Data Driven Simulation of Maritime Pirate Activity

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2017-01-01

    Full Text Available Maritime piracy is posing a genuine threat to maritime transport. The main purpose of simulation is to predict the behaviors of many actual systems, and it has been successfully applied in many fields. But the application of simulation in the maritime domain is still scarce. The rapid development of network and measurement technologies brings about higher accuracy and better availability of online measurements. This makes the simulation paradigm named as dynamic data driven simulation increasingly popular. It can assimilate the online measurements into the running simulation models and ensure much more accurate prediction of the complex systems under study. In this paper, we study how to utilize the online measurements in the agent based simulation of the maritime pirate activity. A new random finite set based data assimilation algorithm is proposed to overcome the limitations of the conventional vectors based data assimilation algorithms. The random finite set based general data model, measurement model, and simulation model are introduced to support the proposed algorithm. The details of the proposed algorithm are presented in the context of agent based simulation of maritime pirate activity. Two groups of experiments are used to practically prove the effectiveness and superiority of the proposed algorithm.

  19. Assimilative model for ionospheric dynamics employing delay, Doppler, and direction of arrival measurements from multiple HF channels

    Science.gov (United States)

    Fridman, Sergey V.; Nickisch, L. J.; Hausman, Mark; Zunich, George

    2016-03-01

    We describe the development of new HF data assimilation capabilities for our ionospheric inversion algorithm called GPSII (GPS Ionospheric Inversion). Previously existing capabilities of this algorithm included assimilation of GPS total electron content data as well as assimilation of backscatter ionograms. In the present effort we concentrated on developing assimilation tools for data related to HF propagation channels. Measurements of propagation delay, angle of arrival, and the ionosphere-induced Doppler from any number of known propagation links can now be utilized by GPSII. The resulting ionospheric model is consistent with all assimilated measurements. This means that ray tracing simulations of the assimilated propagation links are guaranteed to be in agreement with measured data within the errors of measurement. The key theoretical element for assimilating HF data is the raypath response operator (RPRO) which describes response of raypath parameters to infinitesimal variations of electron density in the ionosphere. We construct the RPRO out of the fundamental solution of linearized ray tracing equations for a dynamic magnetoactive plasma. We demonstrate performance and internal consistency of the algorithm using propagation delay data from multiple oblique ionograms (courtesy of Defence Science and Technology Organisation, Australia) as well as with time series of near-vertical incidence sky wave data (courtesy of the Intelligence Advanced Research Projects Activity HFGeo Program Government team). In all cases GPSII produces electron density distributions which are smooth in space and in time. We simulate the assimilated propagation links by performing ray tracing through GPSII-produced ionosphere and observe that simulated data are indeed in agreement with assimilated measurements.

  20. Multi-modal in vivo imaging of brain blood oxygenation, blood flow and neural calcium dynamics during acute seizures

    Science.gov (United States)

    Ringuette, Dene; Jeffrey, Melanie A.; Carlen, Peter L.; Levi, Ofer

    2016-03-01

    Dysfunction of the vascular endothelium has been implicated in the development of epilepsy. To better understand the relation between vascular function and seizure and provide a foundation for interpreting results from functional imaging in chronic disease models, we investigate the relationship between intracellular calcium dynamics and local cerebral blood flow and blood oxygen saturation during acute seizure-like events and pharmacological seizure rescue. To probe the relation between the aforementioned physiological markers in an acute model of epilepsy in rats, we integrated three different optical modalities together with electrophysiological recordings: Laser speckle contrast imaging (LSCI) was used to study changes in flow speeds, Intrinsic optical signal imaging (IOSI) was used to monitor changes in oxygenated, de-oxygenated, and total hemoglobin concentration, and Calcium-sensitive dye imaging was used to monitor intracellular calcium dynamics. We designed a dedicated cortical flow chamber to remove superficial blood and dye resulting from the injection procedure, which reduced spurious artifacts. The near infrared light used for IOSI and LSCI was delivered via a light pipe integrated with the flow chamber to minimize the effect of fluid surface movement on illumination stability. Calcium-sensitive dye was injected via a glass electrode used for recording the local field potential. Our system allowed us to observe and correlate increases in intracellular calcium, blood flow and blood volume during seizure-like events and provide a quantitative analysis of neurovascular coupling changes associated with seizure rescue via injection of an anti-convulsive agent.

  1. Examining dynamic interactions among experimental factors influencing hydrologic data assimilation with the ensemble Kalman filter

    Science.gov (United States)

    Wang, S.; Huang, G. H.; Baetz, B. W.; Cai, X. M.; Ancell, B. C.; Fan, Y. R.

    2017-11-01

    The ensemble Kalman filter (EnKF) is recognized as a powerful data assimilation technique that generates an ensemble of model variables through stochastic perturbations of forcing data and observations. However, relatively little guidance exists with regard to the proper specification of the magnitude of the perturbation and the ensemble size, posing a significant challenge in optimally implementing the EnKF. This paper presents a robust data assimilation system (RDAS), in which a multi-factorial design of the EnKF experiments is first proposed for hydrologic ensemble predictions. A multi-way analysis of variance is then used to examine potential interactions among factors affecting the EnKF experiments, achieving optimality of the RDAS with maximized performance of hydrologic predictions. The RDAS is applied to the Xiangxi River watershed which is the most representative watershed in China's Three Gorges Reservoir region to demonstrate its validity and applicability. Results reveal that the pairwise interaction between perturbed precipitation and streamflow observations has the most significant impact on the performance of the EnKF system, and their interactions vary dynamically across different settings of the ensemble size and the evapotranspiration perturbation. In addition, the interactions among experimental factors vary greatly in magnitude and direction depending on different statistical metrics for model evaluation including the Nash-Sutcliffe efficiency and the Box-Cox transformed root-mean-square error. It is thus necessary to test various evaluation metrics in order to enhance the robustness of hydrologic prediction systems.

  2. GlnK Facilitates the Dynamic Regulation of Bacterial Nitrogen Assimilation.

    Science.gov (United States)

    Gosztolai, Adam; Schumacher, Jörg; Behrends, Volker; Bundy, Jacob G; Heydenreich, Franziska; Bennett, Mark H; Buck, Martin; Barahona, Mauricio

    2017-05-23

    Ammonium assimilation in Escherichia coli is regulated by two paralogous proteins (GlnB and GlnK), which orchestrate interactions with regulators of gene expression, transport proteins, and metabolic pathways. Yet how they conjointly modulate the activity of glutamine synthetase, the key enzyme for nitrogen assimilation, is poorly understood. We combine experiments and theory to study the dynamic roles of GlnB and GlnK during nitrogen starvation and upshift. We measure time-resolved in vivo concentrations of metabolites, total and posttranslationally modified proteins, and develop a concise biochemical model of GlnB and GlnK that incorporates competition for active and allosteric sites, as well as functional sequestration of GlnK. The model predicts the responses of glutamine synthetase, GlnB, and GlnK under time-varying external ammonium level in the wild-type and two genetic knock-outs. Our results show that GlnK is tightly regulated under nitrogen-rich conditions, yet it is expressed during ammonium run-out and starvation. This suggests a role for GlnK as a buffer of nitrogen shock after starvation, and provides a further functional link between nitrogen and carbon metabolisms. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. The dynamic nature of assimilation and accommodation procedures in the brains of Chinese-English and English-Chinese bilinguals.

    Science.gov (United States)

    Sun, Yafeng; Peng, Danling; Ding, Guosheng; Qi, Ting; Desroches, Amy S; Liu, Li

    2015-10-01

    The framework of assimilation and accommodation has been proposed to explain the brain mechanisms supporting second language reading acquisition (Perfetti et al. [2007]: Bilingual Lang Cogn 10:131). Assimilation refers to using the procedures of the native language network in the acquisition of a new writing system, whereas accommodation refers to using second language procedures for reading the newly acquired writing system. We investigated assimilation and accommodation patterns in the brains of bilingual individuals by recruiting a group of Chinese-English bilinguals and a group of English-Chinese bilinguals to perform lexical decision tasks in both English and Chinese. The key question was whether the assimilation/accommodation procedures supporting second language reading in the brains of Chinese-English and English-Chinese bilinguals were dynamic, i.e., modulated by proficiency in the second language and perceptual features of the second language's script. Perceptual features of the scripts were manipulated through orthographic degradation by inserting spaces between the radicals of a Chinese character or between the syllables of an English word. This manipulation disrupts the visual configuration of the orthography but does not change its more fundamental design principles. We found that for English-Chinese bilinguals, higher proficiency was associated with greater accommodation, suggesting that the accommodation procedure in a bilingual individual's brain is modulated by second language proficiency. Most interestingly, we found that the assimilation/accommodation effects vanished or diminished when orthographically degraded scripts were processed by both Chinese-English and English-Chinese bilinguals, suggesting that the assimilation/accommodation procedures in a bilingual individual's brain are modulated by perceptual features of orthography. This work therefore offers a new, dynamic perspective for our understanding of the assimilation

  4. Metabolic and Homeostatic Changes in Seizures and Acquired Epilepsy—Mitochondria, Calcium Dynamics and Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Stjepana Kovac

    2017-09-01

    Full Text Available Acquired epilepsies can arise as a consequence of brain injury and result in unprovoked seizures that emerge after a latent period of epileptogenesis. These epilepsies pose a major challenge to clinicians as they are present in the majority of patients seen in a common outpatient epilepsy clinic and are prone to pharmacoresistance, highlighting an unmet need for new treatment strategies. Metabolic and homeostatic changes are closely linked to seizures and epilepsy, although, surprisingly, no potential treatment targets to date have been translated into clinical practice. We summarize here the current knowledge about metabolic and homeostatic changes in seizures and acquired epilepsy, maintaining a particular focus on mitochondria, calcium dynamics, reactive oxygen species and key regulators of cellular metabolism such as the Nrf2 pathway. Finally, we highlight research gaps that will need to be addressed in the future which may help to translate these findings into clinical practice.

  5. Capturing Dynamics in the Power Grid: Formulation of Dynamic State Estimation through Data Assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ning [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Zhenyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meng, Da [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elbert, Stephen T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Shaobu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diao, Ruisheng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-03-31

    With the increasing complexity resulting from uncertainties and stochastic variations introduced by intermittent renewable energy sources, responsive loads, mobile consumption of plug-in vehicles, and new market designs, more and more dynamic behaviors are observed in everyday power system operation. To operate a power system efficiently and reliably, it is critical to adopt a dynamic paradigm so that effective control actions can be taken in time. The dynamic paradigm needs to include three fundamental components: dynamic state estimation; look-ahead dynamic simulation; and dynamic contingency analysis (Figure 1). These three components answer three basic questions: where the system is; where the system is going; and how secure the system is against accidents. The dynamic state estimation provides a solid cornerstone to support the other 2 components and is the focus of this study.

  6. A Dynamic Approach to Addressing Observation-Minus-Forecast Mean Differences in a Land Surface Skin Temperature Data Assimilation System

    Science.gov (United States)

    Draper, Clara; Reichle, Rolf; De Lannoy, Gabrielle; Scarino, Benjamin

    2015-01-01

    In land data assimilation, bias in the observation-minus-forecast (O-F) residuals is typically removed from the observations prior to assimilation by rescaling the observations to have the same long-term mean (and higher-order moments) as the corresponding model forecasts. Such observation rescaling approaches require a long record of observed and forecast estimates, and an assumption that the O-F mean differences are stationary. A two-stage observation bias and state estimation filter is presented, as an alternative to observation rescaling that does not require a long data record or assume stationary O-F mean differences. The two-stage filter removes dynamic (nonstationary) estimates of the seasonal scale O-F mean difference from the assimilated observations, allowing the assimilation to correct the model for synoptic-scale errors without adverse effects from observation biases. The two-stage filter is demonstrated by assimilating geostationary skin temperature (Tsk) observations into the Catchment land surface model. Global maps of the O-F mean differences are presented, and the two-stage filter is evaluated for one year over the Americas. The two-stage filter effectively removed the Tsk O-F mean differences, for example the GOES-West O-F mean difference at 21:00 UTC was reduced from 5.1 K for a bias-blind assimilation to 0.3 K. Compared to independent in situ and remotely sensed Tsk observations, the two-stage assimilation reduced the unbiased Root Mean Square Difference (ubRMSD) of the modeled Tsk by 10 of the open-loop values.

  7. A pseudoproxy assessment of data assimilation for reconstructing the atmosphere-ocean dynamics of hydroclimate extremes

    Science.gov (United States)

    Steiger, Nathan J.; Smerdon, Jason E.

    2017-10-01

    Because of the relatively brief observational record, the climate dynamics that drive multiyear to centennial hydroclimate variability are not adequately characterized and understood. Paleoclimate reconstructions based on data assimilation (DA) optimally fuse paleoclimate proxies with the dynamical constraints of climate models, thus providing a coherent dynamical picture of the past. DA is therefore an important new tool for elucidating the mechanisms of hydroclimate variability over the last several millennia. But DA has so far remained untested for global hydroclimate reconstructions. Here we explore whether or not DA can be used to skillfully reconstruct global hydroclimate variability along with the driving climate dynamics. Through a set of idealized pseudoproxy experiments, we find that an established DA reconstruction approach can in principle be used to reconstruct hydroclimate at both annual and seasonal timescales. We find that the skill of such reconstructions is generally highest near the proxy sites. This set of reconstruction experiments is specifically designed to estimate a realistic upper bound for the skill of this DA approach. Importantly, this experimental framework allows us to see where and for what variables the reconstruction approach may never achieve high skill. In particular for tree rings, we find that hydroclimate reconstructions depend critically on moisture-sensitive trees, while temperature reconstructions depend critically on temperature-sensitive trees. Real-world DA-based reconstructions will therefore likely require a spatial mixture of temperature- and moisture-sensitive trees to reconstruct both temperature and hydroclimate variables. Additionally, we illustrate how DA can be used to elucidate the dynamical mechanisms of drought with two examples: tropical drivers of multiyear droughts in the North American Southwest and in equatorial East Africa. This work thus provides a foundation for future DA-based hydroclimate

  8. A pseudoproxy assessment of data assimilation for reconstructing the atmosphere–ocean dynamics of hydroclimate extremes

    Directory of Open Access Journals (Sweden)

    N. J. Steiger

    2017-10-01

    Full Text Available Because of the relatively brief observational record, the climate dynamics that drive multiyear to centennial hydroclimate variability are not adequately characterized and understood. Paleoclimate reconstructions based on data assimilation (DA optimally fuse paleoclimate proxies with the dynamical constraints of climate models, thus providing a coherent dynamical picture of the past. DA is therefore an important new tool for elucidating the mechanisms of hydroclimate variability over the last several millennia. But DA has so far remained untested for global hydroclimate reconstructions. Here we explore whether or not DA can be used to skillfully reconstruct global hydroclimate variability along with the driving climate dynamics. Through a set of idealized pseudoproxy experiments, we find that an established DA reconstruction approach can in principle be used to reconstruct hydroclimate at both annual and seasonal timescales. We find that the skill of such reconstructions is generally highest near the proxy sites. This set of reconstruction experiments is specifically designed to estimate a realistic upper bound for the skill of this DA approach. Importantly, this experimental framework allows us to see where and for what variables the reconstruction approach may never achieve high skill. In particular for tree rings, we find that hydroclimate reconstructions depend critically on moisture-sensitive trees, while temperature reconstructions depend critically on temperature-sensitive trees. Real-world DA-based reconstructions will therefore likely require a spatial mixture of temperature- and moisture-sensitive trees to reconstruct both temperature and hydroclimate variables. Additionally, we illustrate how DA can be used to elucidate the dynamical mechanisms of drought with two examples: tropical drivers of multiyear droughts in the North American Southwest and in equatorial East Africa. This work thus provides a foundation for future DA

  9. Soil thermal dynamics, snow cover, and frozen depth under five temperature treatments in an ombrotrophic bog: Constrained forecast with data assimilation: Forecast With Data Assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yuanyuan [Department of Microbiology and Plant Biology, University of Oklahoma, Norman Oklahoma USA; Jiang, Jiang [Department of Microbiology and Plant Biology, University of Oklahoma, Norman Oklahoma USA; Key Laboratory of Soil and Water Conservation and Ecological Restoration in Jiangsu Province, Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Nanjing Forestry University, Nanjing China; Ma, Shuang [Department of Microbiology and Plant Biology, University of Oklahoma, Norman Oklahoma USA; Ricciuto, Daniel [Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Hanson, Paul J. [Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Luo, Yiqi [Department of Microbiology and Plant Biology, University of Oklahoma, Norman Oklahoma USA; Department of Earth System Science, Tsinghua University, Beijing China

    2017-08-01

    Accurate simulation of soil thermal dynamics is essential for realistic prediction of soil biogeochemical responses to climate change. To facilitate ecological forecasting at the Spruce and Peatland Responses Under Climatic and Environmental change site, we incorporated a soil temperature module into a Terrestrial ECOsystem (TECO) model by accounting for surface energy budget, snow dynamics, and heat transfer among soil layers and during freeze-thaw events. We conditioned TECO with detailed soil temperature and snow depth observations through data assimilation before the model was used for forecasting. The constrained model reproduced variations in observed temperature from different soil layers, the magnitude of snow depth, the timing of snowfall and snowmelt, and the range of frozen depth. The conditioned TECO forecasted probabilistic distributions of soil temperature dynamics in six soil layers, snow, and frozen depths under temperature treatments of +0.0, +2.25, +4.5, +6.75, and +9.0°C. Air warming caused stronger elevation in soil temperature during summer than winter due to winter snow and ice. And soil temperature increased more in shallow soil layers in summer in response to air warming. Whole ecosystem warming (peat + air warmings) generally reduced snow and frozen depths. The accuracy of forecasted snow and frozen depths relied on the precision of weather forcing. Uncertainty is smaller for forecasting soil temperature but large for snow and frozen depths. Timely and effective soil thermal forecast, constrained through data assimilation that combines process-based understanding and detailed observations, provides boundary conditions for better predictions of future biogeochemical cycles.

  10. Assimilation of Remotely-Sensed Leaf Area Index into a Dynamic Vegetation Model for Gross Primary Productivity Estimation

    Directory of Open Access Journals (Sweden)

    Rui Ma

    2017-02-01

    Full Text Available Quantitative estimation of the magnitude and variability of gross primary productivity (GPP is required to study the carbon cycle of the terrestrial ecosystem. Using ecosystem models and remotely-sensed data is a practical method for accurately estimating GPP. This study presents a method for assimilating high-quality leaf area index (LAI products retrieved from satellite data into a process-oriented Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM to acquire accurate GPP. The assimilation methods, including the Ensemble Kalman Filter (EnKF and a proper orthogonal decomposition (POD-based ensemble four-dimensional (4D variational assimilation method (PODEn4DVar, incorporate information provided by observations into the model to achieve a better agreement between the model-estimated and observed GPP. The LPJ-POD scheme performs better with a correlation coefficient of r = 0.923 and RMSD of 32.676 gC/m2/month compared with the LPJ-EnKF scheme (r = 0.887, RMSD = 38.531 gC/m2/month and with no data assimilation (r = 0.840, RMSD = 45.410 gC/m2/month. Applying the PODEn4DVar method into LPJ-DGVM for simulating GPP in China shows that the annual amount of GPP in China varied between 5.92 PgC and 6.67 PgC during 2003–2012 with an annual mean of 6.35 PgC/yr. This study demonstrates that integrating remotely-sensed data with dynamic global vegetation models through data assimilation methods has potential in optimizing the simulation and that the LPJ-POD scheme shows better performance in improving GPP estimates, which can provide a favorable way for accurately estimating dynamics of ecosystems.

  11. Dynamics of seizure of animal products in international baggage on Airport of Brasilia (AIB-PJK/SBBR.

    Directory of Open Access Journals (Sweden)

    Cristiano Barros de Melo

    2016-09-01

    Full Text Available ABSTRACT. de Melo C.B., Fino T.C.M., Schwingel F.F., Santiago M.T., de Barros L.F.R., McManus C. & Sá M.E.P. [Dynamics of seizure of animal products in international baggage on Airport of Brasilia (AIB-PJK/SBBR.] Dinâmica da apreensão de produtos de origem animal em bagagens internacionais no Aeroporto de Brasília (AIB-PJK/SBBR. Revista Brasileira de Medicina Veterinária, 38(3:265-276, 2016. Universidade de Brasília, PPGCA, Campus Universitário Darcy Ribeiro, ICC Sul, Asa Norte, Brasília, DF 70910-900, Brasil. E-mail: cristianomelo@unb.br The risk of introducing infectious agents increases as the volume of imported products rises. The illegal entry of animal products (POA brought in international passenger baggage is a factor that makes up the risk assessment and that grows proportionally to the intensification of international transit passengers. They evaluated the data on seizures of animal products intercepted in international baggage passengers in Airport of Brasilia (AIB-PJK/SBBR between the years 2010 and 2012. The analysis of the dynamics of these seizures considered the POA category, origin, airline and months more frequently and also verified the correlation between these variables. According to retrospective analysis, nearly eight tons of POA were seized from 52 countries throughout the study period. The results showed Portugal (p <0.0001 as the source of passengers who had higher frequency and quantity of seizures, and, added to other European origins, totaled 84.3% of seizures. The months of July, August and September stood out for the highest number of seizures and greater movement of international passengers. The increase in the number of seizures accompanied by a rise in the percentage of inspected passengers (r=0.69, emphasizing the importance of airport surveillance. According to the calculation of relative risk, passengers from African and South American countries showed greater magnitude of risk to bring animal

  12. Dynamic Susceptibility Contrast Enhanced (DSC) MRI Perfusion and Plasma Cytokine Levels in Patients after Tonic-clonic Seizures.

    Science.gov (United States)

    Filipovic, Tatjana; Popovic, Katarina Surlan; Ihan, Alojz; Vodusek, David Bozidar

    2017-09-01

    Inflammatory events in brain parenchyma and glial tissue are involved in epileptogenesis. Blood concentration of cytokines is shown to be elevated after tonic-clonic seizures. As a result of inflammation, blood-brain barrier leakage occurs. This can be documented by imaging techniques, such is dynamic susceptibility contrast enhanced (DSC) MRI perfusion. Our aim was to check for postictal brain inflammation by studying DSC MRI perfusion and plasma level of cytokines. We looked for correlations between number and type of introducing seizures, postictal plasma level of cytokines and parameters of DSC MRI perfusion. Furthermore, we looked for correlation of those parameters and course of the disease over one year follow up. We prospectively enrolled 30 patients, 8-24 hours after single or repeated tonic-clonic seizures. 25 of them had normal perfusion parameters, while 5 had hyperperfusion. Patients with hyperperfusion were tested again, 3 months later. Two of 5 had hyperperfusion also on control measurements. Number of index seizures negatively correlated with concentration of proinflammatory cytokines IL-10, IFN-ϒ and TNF-α in a whole cohort. In patients with hyperperfusion, there were significantly lower concentrations of antiinflammatory cytokine IL-4 and higher concentrations of proinflammatory TNF-a. Long lasting blood- brain barrier disruption may be crucial for epileptogenesis in selected patients.

  13. Altered fMRI connectivity dynamics in temporal lobe epilepsy might explain seizure semiology

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    Helmut eLaufs

    2014-09-01

    Full Text Available Abstract: Temporal lobe epilepsy (TLE can be conceptualized as a network disease. The network can be characterized by inter-regional functional connectivity, i.e. blood oxygen level-dependent (BOLD signal correlations between any two region pairs. However, functional connectivity is not constant over time, thus computing correlation at a given time and then at some later time could give different results (non-stationarity. We hypothesized (1 that non-stationarities can be induced by epilepsy (e.g. interictal epileptic activity increasing local signal variance and that (2 these transient events contribute to fluctuations in connectivity leading to pathological functioning, i.e. TLE semiology. We analyzed fMRI data from 27 patients with TLE and 22 healthy controls focusing on EEG-confirmed wake epochs only to protect against sleep-induced connectivity changes. Testing hypothesis (1, we identified brain regions where the BOLD signal variance was significantly greater in TLE than in controls: the temporal pole - including the hippocampus. Taking the latter as the seed region and testing hypothesis (2 we calculated the time-varying interregional correlation values (dynamic functional connectivity to other brain regions and found greater connectivity variance in the TLE than the control group mainly in the precuneus, the supplementary and sensori-motor and the frontal cortices.We conclude that the highest BOLD signal variance in the hippocampi is highly suggestive of a specific epilepsy-related effect. The altered connectivity dynamics in TLE patients might help to explain the hallmark semiological features of dyscognitive seizures including impaired consciousness (precuneus, frontal cortex, sensory disturbance and motor automatisms (sensorimotor cortices, supplementary motor cortex. Accounting for the non-stationarity and state-dependence of functional connectivity are a prerequisite in the search for potential connectivity-derived biomarkers in TLE.

  14. Altered FMRI connectivity dynamics in temporal lobe epilepsy might explain seizure semiology.

    Science.gov (United States)

    Laufs, Helmut; Rodionov, Roman; Thornton, Rachel; Duncan, John Sydney; Lemieux, Louis; Tagliazucchi, Enzo

    2014-01-01

    Temporal lobe epilepsy (TLE) can be conceptualized as a network disease. The network can be characterized by inter-regional functional connectivity, i.e., blood oxygen level-dependent (BOLD) signal correlations between any two regions. However, functional connectivity is not constant over time, thus computing correlation at a given time and then at some later time could give different results (non-stationarity). We hypothesized (1) that non-stationarities can be induced by epilepsy (e.g., interictal epileptic activity) increasing local signal variance and that (2) these transient events contribute to fluctuations in connectivity leading to pathological functioning, i.e., TLE semiology. We analyzed fMRI data from 27 patients with TLE and 22 healthy controls focusing on EEG-confirmed wake epochs only to protect against sleep-induced connectivity changes. Testing hypothesis (1), we identified brain regions where the BOLD signal variance was significantly greater in TLE than in controls: the temporal pole - including the hippocampus. Taking the latter as the seed region and testing hypothesis (2), we calculated the time-varying inter-regional correlation values (dynamic functional connectivity) to other brain regions and found greater connectivity variance in the TLE than the control group mainly in the precuneus, the supplementary and sensorimotor, and the frontal cortices. We conclude that the highest BOLD signal variance in the hippocampi is highly suggestive of a specific epilepsy-related effect. The altered connectivity dynamics in TLE patients might help to explain the hallmark semiological features of dyscognitive seizures including impaired consciousness (precuneus, frontal cortex), sensory disturbance, and motor automatisms (sensorimotor cortices, supplementary motor cortex). Accounting for the non-stationarity and state-dependence of functional connectivity are a prerequisite in the search for potential connectivity-derived biomarkers in TLE.

  15. Critical dynamics of Hopf bifurcations in the corticothalamic system: Transitions from normal arousal states to epileptic seizures

    Science.gov (United States)

    Yang, Dong-Ping; Robinson, P. A.

    2017-04-01

    A physiologically based corticothalamic model of large-scale brain activity is used to analyze critical dynamics of transitions from normal arousal states to epileptic seizures, which correspond to Hopf bifurcations. This relates an abstract normal form quantitatively to underlying physiology that includes neural dynamics, axonal propagation, and time delays. Thus, a bridge is constructed that enables normal forms to be used to interpret quantitative data. The normal form of the Hopf bifurcations with delays is derived using Hale's theory, the center manifold theorem, and normal form analysis, and it is found to be explicitly expressed in terms of transfer functions and the sensitivity matrix of a reduced open-loop system. It can be applied to understand the effect of each physiological parameter on the critical dynamics and determine whether the Hopf bifurcation is supercritical or subcritical in instabilities that lead to absence and tonic-clonic seizures. Furthermore, the effects of thalamic and cortical nonlinearities on the bifurcation type are investigated, with implications for the roles of underlying physiology. The theoretical predictions about the bifurcation type and the onset dynamics are confirmed by numerical simulations and provide physiologically based criteria for determining bifurcation types from first principles. The results are consistent with experimental data from previous studies, imply that new regimes of seizure transitions may exist in clinical settings, and provide a simplified basis for control-systems interventions. Using the normal form, and the full equations from which it is derived, more complex dynamics, such as quasiperiodic cycles and saddle cycles, are discovered near the critical points of the subcritical Hopf bifurcations.

  16. Critical dynamics of Hopf bifurcations in the corticothalamic system: Transitions from normal arousal states to epileptic seizures.

    Science.gov (United States)

    Yang, Dong-Ping; Robinson, P A

    2017-04-01

    A physiologically based corticothalamic model of large-scale brain activity is used to analyze critical dynamics of transitions from normal arousal states to epileptic seizures, which correspond to Hopf bifurcations. This relates an abstract normal form quantitatively to underlying physiology that includes neural dynamics, axonal propagation, and time delays. Thus, a bridge is constructed that enables normal forms to be used to interpret quantitative data. The normal form of the Hopf bifurcations with delays is derived using Hale's theory, the center manifold theorem, and normal form analysis, and it is found to be explicitly expressed in terms of transfer functions and the sensitivity matrix of a reduced open-loop system. It can be applied to understand the effect of each physiological parameter on the critical dynamics and determine whether the Hopf bifurcation is supercritical or subcritical in instabilities that lead to absence and tonic-clonic seizures. Furthermore, the effects of thalamic and cortical nonlinearities on the bifurcation type are investigated, with implications for the roles of underlying physiology. The theoretical predictions about the bifurcation type and the onset dynamics are confirmed by numerical simulations and provide physiologically based criteria for determining bifurcation types from first principles. The results are consistent with experimental data from previous studies, imply that new regimes of seizure transitions may exist in clinical settings, and provide a simplified basis for control-systems interventions. Using the normal form, and the full equations from which it is derived, more complex dynamics, such as quasiperiodic cycles and saddle cycles, are discovered near the critical points of the subcritical Hopf bifurcations.

  17. Constraining the plasmasphere dynamics with multiple data sets and data assimilation

    Science.gov (United States)

    Jorgensen, A. M.; Lichtenberger, J.; Heilig, B.; Vellante, M.; Reda, J.; Friedel, R. H. W.; Henderson, M. G.; Ober, D. M.; Boudouridis, A.; Zesta, E.; Chi, P. J.; Cho, J.; Katus, R. M.

    2014-12-01

    The Earth's plasmasphere is a region of dense plasma, originating inthe ionosphere, extending nearly to geostationary orbit. The preciseextent of the plasmasphere is dynamic, particularly duringgeomagnetic active conditions. Knowing the exact distribution ofplasma in the plasmasphere is important as an input to coupledmagnetospheric models. In particular, density gradients inside theplasmasphere and at the plasmapause, are important in controllingwaves which are responsible for the growth and decay of the radiationbelts. At the most basic level the plasmasphere can be described interms of plasma exchange with the ionosphere and convection due to animposed electric field. At that level plasmasphere modeling isrelatively simple. However there is currently insufficient knowledgeof the drivers, particularly the electric field, to model theplasmasphere boundaries at the most accurate level to providesufficient quality inputs to wave and radiation belt models. One solution to this problem is to use a data assimilationapproach. Data assimilation wraps a feedback loop around theplasmasphere model in which free, ideally unknown, model parametersare adjusted to maximize the agreement between the model andobservations. There are many possible implementations of this feedbackloop. We use the Ensemble Kalman Filter in which a statisticalensemble of models tracks the observations through lineartransformations. In previous work we have used either ground-basedobservations from the PLASMON project (funded by the European SeventhFramework Program), or a small number of space-based observations. Thenext step is to use a larger number of data sources, including avariety of ground-based and space-based observations as well as otherknowledge contains in empirical models. We will discuss our approachto incorporating disparate data sets and demonstrate some assimilationresults which combine different data sources.

  18. Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation

    Science.gov (United States)

    Beverlin II, Bryce; Netoff, Theoden I.

    2013-01-01

    Seizure control using deep brain stimulation (DBS) provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris–Lecar (M–L) model neurons connected with depressing synapses. Cells are connected using second order network topology (SONET) to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control. PMID:23390413

  19. Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation

    Directory of Open Access Journals (Sweden)

    Bryce eBeverlin II

    2013-02-01

    Full Text Available Seizure control using deep brain stimulation (DBS provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris-Lecar model neurons connected with depressing synapses. Cells are connected using second order network topology to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control.

  20. [Ecstatic seizures].

    Science.gov (United States)

    Likhachev, S A; Astapenko, A V; Osos, E L; Zmachynskaya, O L; Gvishch, T G

    2015-01-01

    Ecstatic seizures is a rare manifestation of epilepsy. They were described for the first time by F.M. Dostoevsky. Currently, the description of ecstatic seizures is possible to find in the scientific literature. The description of the own observation of a patient with emotional-affective seizures is presented. A role of the anterior insular cortex in the ecstatic seizures origin is discussed. The similarities between the feelings reported during ecstatic seizures and the feelings experienced under the effect of stimulant addictive drugs are described. The possible reasons of the low frequency of emotional-affective seizures are considered.

  1. Non-Gaussian data assimilation of satellite-based leaf area index observations with an individual-based dynamic global vegetation model

    Science.gov (United States)

    Arakida, Hazuki; Miyoshi, Takemasa; Ise, Takeshi; Shima, Shin-ichiro; Kotsuki, Shunji

    2017-09-01

    We developed a data assimilation system based on a particle filter approach with the spatially explicit individual-based dynamic global vegetation model (SEIB-DGVM). We first performed an idealized observing system simulation experiment to evaluate the impact of assimilating the leaf area index (LAI) data every 4 days, simulating the satellite-based LAI. Although we assimilated only LAI as a whole, the tree and grass LAIs were estimated separately with high accuracy. Uncertain model parameters and other state variables were also estimated accurately. Therefore, we extended the experiment to the real world using the real Moderate Resolution Imaging Spectroradiometer (MODIS) LAI data and obtained promising results.

  2. Multiscale Dynamics and Information in Data Collection and Assimilation for Environmental Applications

    Science.gov (United States)

    2015-07-30

    the Department of Defense, Executive Service Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law , no...and statistical learning . A new particle filtering algorithm based on the theoretical result that combines stochastic homogenization with filtering...Non- linear filtering and data assimilation, The International Centre for Theoretical Sciences ( ICTS ) -Tata Institute of Fundamental Research (TIFR

  3. Absence Seizure (Petit Mal Seizure)

    Science.gov (United States)

    ... the seizures continue to occur despite taking anti-seizure medication Contact 911 or emergency services in your area: If you observe prolonged automatic behaviors lasting minutes to hours — activities such as eating or moving ... any seizure lasting more than five minutes Causes Many children ...

  4. System characterization of neuronal excitability in the hippocampus and its relevance to observed dynamics of spontaneous seizure-like transitions

    Science.gov (United States)

    Zalay, Osbert C.; Serletis, Demitre; Carlen, Peter L.; Bardakjian, Berj L.

    2010-06-01

    Most forms of epilepsy are marked by seizure episodes that arise spontaneously. The low-magnesium/high-potassium (low-Mg2+/high-K+) experimental model of epilepsy is an acute model that produces spontaneous, recurring seizure-like events (SLEs). To elucidate the nature of spontaneous seizure transitions and their relationship to neuronal excitability, whole-cell recordings from the intact hippocampus were undertaken in vitro, and the response of hippocampal CA3 neurons to Gaussian white noise injection was obtained before and after treatment with various concentrations of low-Mg2+/high-K+ solution. A second-order Volterra kernel model was estimated for each of the input-output response pairs. The spectral energy of the responses was also computed, providing a quantitative measure of neuronal excitability. Changes in duration and amplitude of the first-order kernel correlated positively with the spectral energy increase following treatment with low-Mg2+/high-K+ solution, suggesting that variations in neuronal excitability are coded by the system kernels, in part by differences to the profile of the first-order kernel. In particular, kernel duration was more sensitive than amplitude to changes in spectral energy, and correlated more strongly with kernel area. An oscillator network model of the hippocampal CA3 was constructed to investigate the relationship of kernel duration to network excitability, and the model was able to generate spontaneous, recurrent SLEs by increasing the duration of a mode function analogous to the first-order kernel. Results from the model indicated that disruption to the dynamic balance of feedback was responsible for seizure-like transitions and the observed intermittency of SLEs. A physiological candidate for feedback imbalance consistent with the network model is the destabilizing interaction of extracellular potassium and paroxysmal neuronal activation. Altogether, these results (1) validate a mathematical model for epileptiform

  5. Wavelet-based Gaussian-mixture hidden Markov model for the detection of multistage seizure dynamics: A proof-of-concept study

    Directory of Open Access Journals (Sweden)

    Carlen Peter L

    2011-04-01

    validated with experimental intracellular electrical recordings of seizures. Conclusions The HMM implementation of a seizure dynamics detector is an improvement over existing approaches using visual detection and complexity measures. The subjectivity involved in partitioning the observed data prior to training can be eliminated. It can also decipher the probabilities of seizure state transitions using the magnitude and rate of change wavelet information of the LFPs.

  6. Dynamical changes in neurons during seizures determine tonic to clonic shift.

    Science.gov (United States)

    Beverlin, Bryce; Kakalios, James; Nykamp, Duane; Netoff, Theoden Ivan

    2012-08-01

    A tonic-clonic seizure transitions from high frequency asynchronous activity to low frequency coherent oscillations, yet the mechanism of transition remains unknown. We propose a shift in network synchrony due to changes in cellular response. Here we use phase-response curves (PRC) from Morris-Lecar (M-L) model neurons with synaptic depression and gradually decrease input current to cells within a network simulation. This method effectively decreases firing rates resulting in a shift to greater network synchrony illustrating a possible mechanism of the transition phenomenon. PRCs are measured from the M-L conductance based model cell with a range of input currents within the limit cycle. A large network of 3000 excitatory neurons is simulated with a network topology generated from second-order statistics which allows a range of population synchrony. The population synchrony of the oscillating cells is measured with the Kuramoto order parameter, which reveals a transition from tonic to clonic phase exhibited by our model network. The cellular response shift mechanism for the tonic-clonic seizure transition reproduces the population behavior closely when compared to EEG data.

  7. Dynamics of regional brain activity in epilepsy: a cross-disciplinary study on both intracranial and scalp-recorded epileptic seizures

    Science.gov (United States)

    Minadakis, George; Ventouras, Errikos; Gatzonis, Stylianos D.; Siatouni, Anna; Tsekou, Hara; Kalatzis, Ioannis; Sakas, Damianos E.; Stonham, John

    2014-04-01

    Objective. Recent cross-disciplinary literature suggests a dynamical analogy between earthquakes and epileptic seizures. This study extends the focus of inquiry for the applicability of models for earthquake dynamics to examine both scalp-recorded and intracranial electroencephalogram recordings related to epileptic seizures. Approach. First, we provide an updated definition of the electric event in terms of magnitude and we focus on the applicability of (i) a model for earthquake dynamics, rooted in a nonextensive Tsallis framework, (ii) the traditional Gutenberg and Richter law and (iii) an alternative method for the magnitude-frequency relation for earthquakes. Second, we apply spatiotemporal analysis in terms of nonextensive statistical physics and we further examine the behavior of the parameters included in the nonextensive formula for both types of electroencephalogram recordings under study. Main results. We confirm the previously observed power-law distribution, showing that the nonextensive formula can adequately describe the sequences of electric events included in both types of electroencephalogram recordings. We also show the intermittent behavior of the epileptic seizure cycle which is analogous to the earthquake cycles and we provide evidence of self-affinity of the regional electroencephalogram epileptic seizure activity. Significance. This study may provide a framework for the analysis and interpretation of epileptic brain activity and other biological phenomena with similar underlying dynamical mechanisms.

  8. Toward a dynamic-thermodynamic assimilation of satellite surface temperature in numerical atmospheric models

    Science.gov (United States)

    Mcnider, Richard T.; Song, Aaron J.; Casey, Daniel M.; Wetzel, Peter J.; Crosson, William L.; Rabin, Robert M.

    1994-01-01

    An assimilation technique is described in which satellite-observed surface skin temperature tendencies are used in a model surface energy budget so that the predicted rate of temperature change in the model more closely agrees with the satellite observations. Both visible and infrared GOES satellite data are used in the assimilation. The technique is based on analytically recovering surface moisture from similarity expressions derived from an evapotranspiration residual obtained as a difference between the unadjusted model evapotranspiration and the satellite-inferred evapotranspiration. The technique has application in regional-scale models where surface parameters such as root zone moisture, soil moisture, etc., are unknown. It is assumed that the largest error in the surface energy budget is in the evapotranspiration term. Two tests are given for the technique, first, a one-dimensional test against FIFE data and, second, a three-dimensional test over Oklahoma. In these cases the technique appears to correctly adjust the model response to agree better with observations.

  9. A simple dynamical model of cumulus convection for data assimilation research

    Directory of Open Access Journals (Sweden)

    Michael Würsch

    2014-12-01

    Full Text Available A simplified model for cumulus convection has been developed, with the aim of providing a computationally inexpensive, but physically plausible, environment for developing methods for convective-scale data assimilation. Key processes, including gravity waves, conditional instability and precipitation formation, are represented, and parameter values are chosen to reproduce the most important space and time scales of cumulus clouds. The model is shown to reproduce the classic life cycle of an isolated convective storm. When provided with a low amplitude noise source to trigger convection, the model produces a statistically steady state with cloud size and cloud spacing distributions similar to those found in radiative-convective equilibrium simulations using a cloud resolving model. Results are also shown for convection triggered by flow over an orgraphic obstacle, where depending on the wind speed two regimes are found with convection trapped over the mountain, or propagating downstream. The model features prognostic variables for wind and rain that can be used to compute synthetic observations for data assimilation experiments.

  10. Which Brain Regions are Important for Seizure Dynamics in Epileptic Networks? Influence of Link Identification and EEG Recording Montage on Node Centralities.

    Science.gov (United States)

    Geier, Christian; Lehnertz, Klaus

    2017-02-01

    Nodes in large-scale epileptic networks that are crucial for seizure facilitation and termination can be regarded as potential targets for individualized focal therapies. Graph-theoretical approaches based on centrality concepts can help to identify such important nodes, however, they may be influenced by the way networks are derived from empirical data. Here we investigate evolving functional epileptic brain networks during 82 focal seizures with different anatomical onset locations that we derive from multichannel intracranial electroencephalographic recordings from 51 patients. We demonstrate how the various methodological steps (from the recording montage via node and link inference to the assessment of node centralities) affect importance estimation and discuss their impact on the interpretability of findings in the context of pathophysiological aspects of seizure dynamics.

  11. Wavelet Jensen Shannon divergence as a tool for studying the dynamics of frequency band components in EEG epileptic seizures

    Science.gov (United States)

    Pereyra, M. E.; Lamberti, P. W.; Rosso, O. A.

    2007-06-01

    We develop a quantitative method of analysis of EEG records. The method is based on the wavelet analysis of the record and on the capability of the Jensen-Shannon divergence (JSD) to identify dynamical changes in a time series. The JSD is a measure of distance between probability distributions. Therefore for its evaluation it is necessary to define a (time dependent) probability distribution along the record. We define this probability distribution from the wavelet decomposition of the associated time series. The wavelet JSD provides information about dynamical changes in the scales and can be considered a complementary methodology reported earlier [O.A. Rosso, S. Blanco, A. Rabinowicz, Signal Processing 86 (2003) 1275; O.A. Rosso, S. Blanco, J. Yordanova, V. Kolev, A. Figliola, M. Schürmann, E. Başar, J. Neurosci. Methods 105 (2001) 65; O.A. Rosso, M.T. Martin, A. Figliola, K. Keller, A. Plastino, J. Neurosci. Methods 153 (2006) 163]. In the present study we have demonstrated it by analyzing EEG signal of tonic-clonic epileptic seizures applying the JSD method. The display of the JSD curves enables easy comparison of frequency band component dynamics. This would, in turn, promise easy and successful comparison of the EEG records from various scalp locations of the brain.

  12. Assimilation and Individual Differences in Emotion: The Dynamics of Anger and Approach Motivation

    Science.gov (United States)

    Lechuga, Julia; Fernandez, Norma P.

    2011-01-01

    Individuals who cross cultural boundaries face many challenges when trying to adapt to a receiving culture. Adaptation challenges such as learning to maneuver across societal domains may become increasingly complex if structural level factors such as discrimination are present. Researchers have conceptualized acculturation as a relatively autonomous decision indicating that four acculturation strategies exist: assimilation, separation, integration, and marginalization. Moreover, researchers have also long debated the link between acculturation strategy, adaptation hassles and negative health outcomes. However, models seeking to explain how individual difference and structural level variables may influence each other and subsequently influence acculturation and adaptation are needed. The purpose of this study is to lay the foundation for the conceptualization of such a model. We propose that temperamental predispositions to negative emotionality, anger, and impulsivity may highlight discrimination which in turn may lead to increases in acculturative stress and negative markers of psychosocial well-being. We used SEM to test our hypothesized model. Results supported a modified model. Implications for the measurement of adaptation and interventions are discussed. PMID:21625350

  13. Assimilation and Individual Differences in Emotion: The Dynamics of Anger and Approach Motivation.

    Science.gov (United States)

    Lechuga, Julia; Fernandez, Norma P

    2011-03-01

    Individuals who cross cultural boundaries face many challenges when trying to adapt to a receiving culture. Adaptation challenges such as learning to maneuver across societal domains may become increasingly complex if structural level factors such as discrimination are present. Researchers have conceptualized acculturation as a relatively autonomous decision indicating that four acculturation strategies exist: assimilation, separation, integration, and marginalization. Moreover, researchers have also long debated the link between acculturation strategy, adaptation hassles and negative health outcomes. However, models seeking to explain how individual difference and structural level variables may influence each other and subsequently influence acculturation and adaptation are needed. The purpose of this study is to lay the foundation for the conceptualization of such a model. We propose that temperamental predispositions to negative emotionality, anger, and impulsivity may highlight discrimination which in turn may lead to increases in acculturative stress and negative markers of psychosocial well-being. We used SEM to test our hypothesized model. Results supported a modified model. Implications for the measurement of adaptation and interventions are discussed.

  14. Remote sensing data assimilation in modeling urban dynamics: Objectives and methodology

    NARCIS (Netherlands)

    Kwast, J. van der; Canters, F.; Karssenberg, D.J.; Engelen, G.; Van de Voorde, T.; Uljee, I.; Jong, K. de

    2011-01-01

    The problem analysis, planning and monitoring phases of sustainable urban management policies require reliable information on the urban environment and its dynamics. Geospatial and socio-economic data supplemented with knowledge on dynamic urban processes are incorporated in the land-use change

  15. An eddy-permitting, dynamically consistent adjoint-based assimilation system for the tropical Pacific: Hindcast experiments in 2000

    KAUST Repository

    Hoteit, Ibrahim

    2010-03-02

    An eddy-permitting adjoint-based assimilation system has been implemented to estimate the state of the tropical Pacific Ocean. The system uses the Massachusetts Institute of Technology\\'s general circulation model and its adjoint. The adjoint method is used to adjust the model to observations by controlling the initial temperature and salinity; temperature, salinity, and horizontal velocities at the open boundaries; and surface fluxes of momentum, heat, and freshwater. The model is constrained with most of the available data sets in the tropical Pacific, including Tropical Atmosphere and Ocean, ARGO, expendable bathythermograph, and satellite SST and sea surface height data, and climatologies. Results of hindcast experiments in 2000 suggest that the iterated adjoint-based descent is able to significantly improve the model consistency with the multivariate data sets, providing a dynamically consistent realization of the tropical Pacific circulation that generally matches the observations to within specified errors. The estimated model state is evaluated both by comparisons with observations and by checking the controls, the momentum balances, and the representation of small-scale features that were not well sampled by the observations used in the assimilation. As part of these checks, the estimated controls are smoothed and applied in independent model runs to check that small changes in the controls do not greatly change the model hindcast. This is a simple ensemble-based uncertainty analysis. In addition, the original and smoothed controls are applied to a version of the model with doubled horizontal resolution resulting in a broadly similar “downscaled” hindcast, showing that the adjustments are not tuned to a single configuration (meaning resolution, topography, and parameter settings). The time-evolving model state and the adjusted controls should be useful for analysis or to supply the forcing, initial, and boundary conditions for runs of other models.

  16. Reconstructing three-dimensional reentrant cardiac electrical wave dynamics using data assimilation

    Science.gov (United States)

    Hoffman, M. J.; LaVigne, N. S.; Scorse, S. T.; Fenton, F. H.; Cherry, E. M.

    2016-01-01

    For many years, reentrant scroll waves have been predicted and studied as an underlying mechanism for cardiac arrhythmias using numerical techniques, and high-resolution mapping studies using fluorescence recordings from the surfaces of cardiac tissue preparations have confirmed the presence of visible spiral waves. However, assessing the three-dimensional dynamics of these reentrant waves using experimental techniques has been limited to verifying stable scroll-wave dynamics in relatively thin preparations. We propose a different approach to recovering the three-dimensional dynamics of reentrant waves in the heart. By applying techniques commonly used in weather forecasting, we combine dual-surface observations from a particular experiment with predictions from a numerical model to reconstruct the full three-dimensional time series of the experiment. Here, we use model-generated surrogate observations from a numerical experiment to evaluate the performance of the ensemble Kalman filter in reconstructing such time series for a discordant alternans state in one spatial dimension and for scroll waves in three dimensions. We show that our approach is able to recover time series of both observed and unobserved variables matching the truth. Where nearby observations are available, the error is reduced below the synthetic observation error, with a smaller reduction with increased distance from observations. Our findings demonstrate that state reconstruction for spatiotemporally complex cardiac electrical dynamics is possible and will lead naturally to applications using real experimental data.

  17. Seizure Prediction and its Applications

    Science.gov (United States)

    Iasemidis, Leon D.

    2011-01-01

    Epilepsy is characterized by intermittent, paroxysmal, hypersynchronous electrical activity, that may remain localized and/or spread and severely disrupt the brain’s normal multi-task and multi-processing function. Epileptic seizures are the hallmarks of such activity and had been considered unpredictable. It is only recently that research on the dynamics of seizure generation by analysis of the brain’s electrographic activity (EEG) has shed ample light on the predictability of seizures, and illuminated the way to automatic, prospective, long-term prediction of seizures. The ability to issue warnings in real time of impending seizures (e.g., tens of minutes prior to seizure occurrence in the case of focal epilepsy), may lead to novel diagnostic tools and treatments for epilepsy. Applications may range from a simple warning to the patient, in order to avert seizure-associated injuries, to intervention by automatic timely administration of an appropriate stimulus, for example of a chemical nature like an anti-epileptic drug (AED), electromagnetic nature like vagus nerve stimulation (VNS), deep brain stimulation (DBS), transcranial direct current (TDC) or transcranial magnetic stimulation (TMS), and/or of another nature (e.g., ultrasonic, cryogenic, biofeedback operant conditioning). It is thus expected that seizure prediction could readily become an integral part of the treatment of epilepsy through neuromodulation, especially in the new generation of closed-loop seizure control systems. PMID:21939848

  18. Age-Dependent Increase of Absence Seizures and Intrinsic Frequency Dynamics of Sleep Spindles in Rats

    Directory of Open Access Journals (Sweden)

    Evgenia Sitnikova

    2014-01-01

    Full Text Available The risk of neurological diseases increases with age. In WAG/Rij rat model of absence epilepsy, the incidence of epileptic spike-wave discharges is known to be elevated with age. Considering close relationship between epileptic spike-wave discharges and physiologic sleep spindles, it was assumed that age-dependent increase of epileptic activity may affect time-frequency characteristics of sleep spindles. In order to examine this hypothesis, electroencephalograms (EEG were recorded in WAG/Rij rats successively at the ages 5, 7, and 9 months. Spike-wave discharges and sleep spindles were detected in frontal EEG channel. Sleep spindles were identified automatically using wavelet-based algorithm. Instantaneous (localized in time frequency of sleep spindles was determined using continuous wavelet transform of EEG signal, and intraspindle frequency dynamics were further examined. It was found that in 5-months-old rats epileptic activity has not fully developed (preclinical stage and sleep spindles demonstrated an increase of instantaneous frequency from beginning to the end. At the age of 7 and 9 months, when animals developed matured and longer epileptic discharges (symptomatic stage, their sleep spindles did not display changes of intrinsic frequency. The present data suggest that age-dependent increase of epileptic activity in WAG/Rij rats affects intrinsic dynamics of sleep spindle frequency.

  19. Short-term dynamics and partitioning of newly assimilated carbon in the foliage of adult beech and pine are driven by seasonal variations

    Science.gov (United States)

    Desalme, Dorine; Priault, Pierrick; Gérant, Dominique; Dannoura, Masako; Maillard, Pascale; Plain, Caroline; Epron, Daniel

    2017-04-01

    Carbon (C) allocation is a key process determining C cycling in forest ecosystems. However, the mechanisms underlying the annual patterns of C partitioning in trees, influenced by tree phenology and environmental conditions, are not well identified yet. This study aimed to characterize the short-term dynamics and partitioning of newly assimilated carbon in the foliage of adult European beeches (Fagus sylvatica) and maritime pines (Pinus pinaster) across the seasons. We hypothesized that residence times of recently assimilated C in C compounds should change according to the seasons and that seasonal pattern should differ between deciduous and evergreen tree species, since they have different phenology. 13CO2 pulse-labelling experiments were performed in situ at different dates corresponding to different phenological stages. In beech leaves and pine needles, C contents, isotopic compositions, and 13C dynamics parameters were determined in total organic matter (bulk foliage), in polar fraction (PF, including soluble sugars, amino acids, organic acids) and in starch. For both species and at each phenological stage, 13C amount in bulk foliage decreased following a two-pool exponential model, highlighting the partitioning of newly assimilated C between 'mobile' and 'stable' pools. The relative proportion of the stable pool was maximal in beech leaves in May, when leaves were still growing and could incorporate newly assimilated C in structural C compounds. Young pine needles were still receiving C from previous-year needles in June (two months after budburst) although they are already photosynthesizing, acting as a strong C sink. In summer, short mean residence times of 13C (MRT) in foliage of both tree species reflected the fast respiration and exportation of recent photosynthates to support the whole tree C demand (e.g., supplying perennial organ growth). At the end of the growing season, pre-senescing beech leaves were supplying 13C to perennial organs, whereas

  20. Spatial assimilation?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    a stronger preference for renting, because of insecurity about their future situation, and that especially newly arrived immigrants live in immigrant dense, so-called multi-ethnic, neighbourhoods. The spatial assimilation theory claims that during the course of time immigrants will move to other kinds....... Part of the initial increase in the frequency of living in multi-ethnic neighbourhoods can be ascribed to the increasing concentration of ethnic minorities in neighbourhoods instead of individual choice among immigrants. The study confirms spatial assimilation, but the change is not dramatic within...

  1. Data Assimilation in Marine Models

    DEFF Research Database (Denmark)

    Frydendall, Jan

    This thesis consists of six research papers published or submitted for publication in the period 2006-2009 together with a summary report. The main topics of this thesis are nonlinear data assimilation techniques and estimation in dynamical models. The focus has been on the nonlinear filtering...... techniques for large scale geophysical numerical models and making them feasible to work with in the data assimilation framework. The filtering techniques investigated are all Monte Carlo simulation based. Some very nice features that can be exploited in the Monte Carlo based data assimilation framework from...... the nonlinearities encountered in data assimilation and at the same time are robust and reliable enough given the constraints and difficulties that can arise. These problems were addressed in the papers A, E and D. The other topic of this thesis is estimation in dynamical geophysical numerical models. The challenge...

  2. Visualization of spatiotemporal energy dynamics of hippocampal neurons by mass spectrometry during a kainate-induced seizure.

    Directory of Open Access Journals (Sweden)

    Yuki Sugiura

    Full Text Available We report the use of matrix-assisted laser desorption/ionization (MALDI imaging mass spectrometry combined with capillary electrophoresis (CE mass spectrometry to visualize energy metabolism in the mouse hippocampus by imaging energy-related metabolites. We show the distribution patterns of ATP, ADP, and AMP in the hippocampus as well as changes in their amounts and distribution patterns in a murine model of limbic, kainate-induced seizure. As an acute response to kainate administration, we found massive and moderate reductions in ATP and ADP levels, respectively, but no significant changes in AMP levels--especially in cells of the CA3 layer. The results suggest the existence of CA3 neuron-selective energy metabolism at the anhydride bonds of ATP and ADP in the hippocampal neurons during seizure. In addition, metabolome analysis of energy synthesis pathways indicates accelerated glycolysis and possibly TCA cycle activity during seizure, presumably due to the depletion of ATP. Consistent with this result, the observed energy depletion significantly recovered up to 180 min after kainate administration. However, the recovery rate was remarkably low in part of the data-pixel population in the CA3 cell layer region, which likely reflects acute and CA3-selective neural death. Taken together, the present approach successfully revealed the spatiotemporal energy metabolism of the mouse hippocampus at a cellular resolution--both quantitatively and qualitatively. We aim to further elucidate various metabolic processes in the neural system.

  3. Epilepsy or seizures - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000128.htm Epilepsy or seizures - discharge To use the sharing features on this page, please enable JavaScript. You have epilepsy . People with epilepsy have seizures. A seizure is ...

  4. Cumulative ozone effect on canopy stomatal resistance and the impact on boundary layer dynamics and CO2 assimilation at the diurnal scale: A case study for grassland in the Netherlands

    NARCIS (Netherlands)

    Super, I.; Vilà-Guerau De Arellano, J.; Krol, M.C.

    2015-01-01

    Biological, chemical, and dynamical processes occurring at the surface strongly interact at diurnal scales. Therefore, this study examines the seasonal ozone impact on stomatal resistance, surface energy balance, boundary layer dynamics, and CO2 assimilation at this (sub)diurnal scale under changing

  5. Dynamics of Control and Resistance: Reactions to the Modern Policy of Assimilation of the Travellers in Norway

    Directory of Open Access Journals (Sweden)

    Rune Halvorsen

    2004-07-01

    Full Text Available For much of the 20th century, the Norwegian authorities pursued a strict assimilation policy towards Travellers (tatere/ romanifolket and their culture. As was the case in many other countries, Travellers were constructed as "the other" (Riggins 1997, MacLaughlin 1999. When compared to other Western European countries, it is, however, surprising that Norwegian Travellers were seen as such a serious problem and threat during the 20th century. The 1845 census counted 1145 Travellers out of a total population of 1.3 million in Norway (Sundt 1852, SSB 1968: Table 13. A private charity organisation acting on behalf of the state registered 5129 "itinerants" in their archives from 1900 to 1959 (Haave 2000. These were the figures that worried the elites. This paper examines the modern assimilation policy and Travellers' reactions to this policy. In particular the paper analyses the internal relation between the modern assimilation policy and the emergence of collective demands for recognition as an ethnic minority and moral redress among Travellers in the 1990s.

  6. Seizures and Teens: Stress, Sleep, & Seizures

    Science.gov (United States)

    Shafer, Patricia Osborne

    2007-01-01

    Most parents are used to erratic sleep patterns and mood swings in their teenagers. When these occur in an adolescent with seizures, however, the parent may wonder if sleep and mood problems are related to seizures. Sorting out the cause and effects of sleep in an adolescent with seizures can be confusing. Since stress can be a contributor to both…

  7. Measuring Income Assimilation of Migrants to Germany

    OpenAIRE

    Ira N. Gang; John Landon-Lane; Myeong-Su Yun

    2009-01-01

    We measure the income assimilation of migrants to Germany employing a new measure of assimilation that uses the whole income distribution rather than selected moments. To do this we implement a discrete-state Markov chain to model the dynamics of the cross-sectional income distribution of migrants and natives in Germany. Bayesian methods allow us to fully characterize the limiting cross-sectional income distribution for migrants and natives, enabling us to compare our measures of assimilation...

  8. Soil thermal dynamics, snow cover, and frozen depth under five temperature treatments in an ombrotrophic bog: Constrained forecast with data assimilation

    Science.gov (United States)

    Huang, Yuanyuan; Jiang, Jiang; Ma, Shuang; Ricciuto, Daniel; Hanson, Paul J.; Luo, Yiqi

    2017-08-01

    Accurate simulation of soil thermal dynamics is essential for realistic prediction of soil biogeochemical responses to climate change. To facilitate ecological forecasting at the Spruce and Peatland Responses Under Climatic and Environmental change site, we incorporated a soil temperature module into a Terrestrial ECOsystem (TECO) model by accounting for surface energy budget, snow dynamics, and heat transfer among soil layers and during freeze-thaw events. We conditioned TECO with detailed soil temperature and snow depth observations through data assimilation before the model was used for forecasting. The constrained model reproduced variations in observed temperature from different soil layers, the magnitude of snow depth, the timing of snowfall and snowmelt, and the range of frozen depth. The conditioned TECO forecasted probabilistic distributions of soil temperature dynamics in six soil layers, snow, and frozen depths under temperature treatments of +0.0, +2.25, +4.5, +6.75, and +9.0°C. Air warming caused stronger elevation in soil temperature during summer than winter due to winter snow and ice. And soil temperature increased more in shallow soil layers in summer in response to air warming. Whole ecosystem warming (peat + air warmings) generally reduced snow and frozen depths. The accuracy of forecasted snow and frozen depths relied on the precision of weather forcing. Uncertainty is smaller for forecasting soil temperature but large for snow and frozen depths. Timely and effective soil thermal forecast, constrained through data assimilation that combines process-based understanding and detailed observations, provides boundary conditions for better predictions of future biogeochemical cycles.

  9. Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Eric T. DeWeaver

    2010-02-17

    The overall goal of work performed under this grant is to enhance understanding of simulations of present-day climate and greenhouse gas-induced climate change. The examination of present-day climate also includes diagnostic intercomparison of model simulations and observed mean climate and climate variability using reanalysis and satellite datasets. Enhanced understanding is desirable 1) as a prerequisite for improving simulations; 2) for assessing the credibility of model simulations and their usefulness as tools for decision support; and 3) as a means to identify robust behaviors which commonly occur over a wide range of models, and may yield insights regarding the dominant physical mechanisms which determine mean climate and produce climate change. A further objective is to investigate the use of data assimilation as a means for examining and correcting model biases. Our primary focus is on the Arctic, but the scope of the work was expanded to include the global climate system.

  10. Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Eric T. DeWeaver

    2010-01-19

    This is the final report for DOE grant DE-FG02-07ER64434 to Eric DeWeaver at the University of Wisconsin-Madison. The overall goal of work performed under this grant is to enhance understanding of simulations of present-day climate and greenhouse gas-induced climate change. Enhanced understanding is desirable 1) as a prerequisite for improving simulations; 2) for assessing the credibility of model simulations and their usefulness as tools for decision support; and 3) as a means to identify robust behaviors which commonly occur over a wide range of models, and may yield insights regarding the dominant physical mechanisms which determine mean climate and produce climate change. A furthe objective is to investigate the use of data assimilation as a means for examining and correcting model biases. Our primary focus is on the Arctic, but the scope of the work was expanded to include the global climate system to the extent that research targets of opportunity present themselves. Research performed under the grant falls into five main research areas: 1) a study of data assimilation using an ensemble filter with the atmospheric circulation model of the National Center for Atmospheric Research, in which both conventional observations and observations of the refraction of radio waves from GPS satellites were used to constrain the atmospheric state of the model; 2) research on the likely future status of polar bears, in which climate model simluations were used to assess the effectiveness of climate change mitigation efforts in preserving the habitat of polar bears, now considered a threatened species under global warming; 3) as assessment of the credibility of Arctic sea ice thickness simulations from climate models; 4) An examination of the persistence and reemergence of Northern Hemisphere sea ice area anomalies in climate model simulations and in observations; 5) An examination of the roles played by changes in net radiation and surface relative humidity in determine the

  11. An application of Data Assimilation to a dynamic global vegetation model: fusing CLM(ED) model results with streams of observed data

    Science.gov (United States)

    Massoud, Elias; Xu, Chonggang; Fisher, Rosie; Vrugt, Jasper

    2016-04-01

    We implement a data assimilation approach for a Dynamic Global Vegetation Model (DGVM), named the CLM(ED) for its combined strengths of a Community Land Model (CLM) and an implementation of the Ecosystem Demography (ED) concept. This unique model combination allows for scaling the behavior of forest ecosystems by aggregating individual trees into representative "cohorts", and thus allows for the prediction of plant distribution (including stem distribution, mortality, and growth) directly from their given physiological traits. The model is constantly improving as it evolves, as less simple empirical models are used and more physically based ones are included to represent the physiological and biogeochemical processes taking place on the land-air surface. For example, very recently a mechanistic model simulating the photosynthetic capacity was implemented for a better representation of a leaf's nitrogen allocation. Some possible outputs of CLM(ED) include GPP, NPP, LAI, and interestingly, predictions of biome boundaries. In this study, we first conduct a global sensitivity analysis by estimating the range of model parameters from literature. Then, an application of Data Assimilation (DA) is introduced, where we attempt to fuse the model simulations with observed data, such as GPP. The updated system properties achieved through DA allow for better parameterization and more accurate overall predictions of vegetation dynamics. More importantly, this study addresses structural uncertainties within the model, and by combining model estimates with observed measurements, we aim to improve the overall representation of the underlying processes by explicitly pinpointing deficiencies in the model structure. We advocate the use of DA in Earth System Models for many reasons, including the direct benefit linked to the recent availability of ecological data sets, the efficient implementation within models thanks to improvements in computational power, and the proven ability of DA

  12. Febrile Seizure Simulation

    Directory of Open Access Journals (Sweden)

    Victor Cisneros

    2017-01-01

    Full Text Available Audience: This simulation session is appropriate for medical students, community physicians, or residents in emergency medicine, neurology, pediatrics, or family medicine. Introduction: Febrile seizures are the most common form of seizures in childhood; they are thought to occur in 2-5% of all children.1-3 Febrile seizures are defined as a seizure in association with a febrile illness in children without a central nervous system infection, previous afebrile seizure, known brain disorder, or electrolyte abnormalities. 1,2 They typically occur between 6 months and 18 months of age though they can occur up to 5 years of age.3 Febrile seizures are categorized as: simple (generalized seizure lasting less than 15 minutes in a child aged 6 months to 5 years, and less than 1 in a 24 hour period or complex (a focal seizure or generalized seizure lasting greater than 15 minutes, or multiple seizures in a 24 hour period. 1,3 Treatment for febrile seizures is based on treating the underlying cause of the fever and giving reassurance and education to the parents.2 Mortality is extremely rare, and there is no difference in the patient’s cognitive abilities after a febrile seizure, even when the seizure is prolonged.1 Objectives: At the end of this simulation session, the learner will be able to: 1 discuss the management of febrile seizures 2 discuss when placement of an advanced airway is indicated in the management of a febrile seizure 3 list the risk factors for febrile seizures 4 prepare a differential diagnosis for the causes of febrile seizures 5 educate family members on febrile seizures. Methods: This educational session is a high-fidelity simulation.

  13. Seizure disorders and epilepsy.

    Science.gov (United States)

    Ozuna, J

    2000-01-01

    Seizures are uncontrolled hypersynchronous electrical discharges of neurons in the brain that interfere with normal function. They are a symptom of an underlying disorder. Epilepsy is a condition of recurring seizures that do not have a reversible metabolic cause. Seizures can be confused with a variety of other conditions, so an understanding of seizure manifestations is crucial in making an accurate diagnosis. Drug therapy is the mainstay of epilepsy treatment, but surgery and vagal nerve stimulation are options for selected refractory cases. Psychosocial consequences of recurring seizures are often more significant to patients than the seizures themselves.

  14. Data assimilation with Chua's circuit

    Indian Academy of Sciences (India)

    noise and observational frequency, using both simulated observations and data obtained from an experimental realization of a commonly used low-dimensional dynamical system, namely, Chua circuit, in both the periodic as well as the chaotic regime. Keywords. Synchronization; ensemble Kalman filter; data assimilation.

  15. Emergency department seizure epidemiology.

    Science.gov (United States)

    Martindale, Jennifer L; Goldstein, Joshua N; Pallin, Daniel J

    2011-02-01

    Although only 3% of people in the United States are diagnosed with epilepsy, 11% will have at least one seizure during their lifetime. Seizures account for about 1% of all emergency department (ED) visits, and about 2% of visits to children's hospital EDs. Seizure accounts for about 3% of prehospital transports. In adult ED patients, common causes of seizure are alcoholism, stroke, tumor, trauma, and central nervous system infection. In children, febrile seizures are most common. In infants younger than 6 months, hyponatremia and infection are important considerations. Epilepsy is an uncommon cause of seizures in the ED, accounting for a minority of seizure-related visits. Of ED patients with seizure, about 7% have status epilepticus, which has an age-dependent mortality averaging 22%. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Seizure Disorders in Pregnancy

    Science.gov (United States)

    ... abnormal. A seizure can cause a change in mood, emotions, consciousness, or movement. What is epilepsy? Epilepsy is ... lead to seizures, which are temporary changes in mood, emotions, consciousness, or movement. Epilepsy is diagnosed if a ...

  17. [Dynamics of ultrastructure changes in sheet plate fiber flax with braking transport assimilate by nitrate-anion].

    Science.gov (United States)

    Abdrakhimov, F A; Batasheva, S N; Bakirova, G G; Chikov, V I

    2008-01-01

    Changes in leaf mesophyll cell ultrastructure under nitrate feeding into the apoplast of common flax (Linum usitatissimum L.) in the form of 50 mM KNO3 solution were studied. In 30 min after the beginning of nitrate feeding through the transpiration water stream, swelling of mitochondrial and microbodies, clarification of their matrices, and curling of dictyosome discs into annular structures were observed. These events characterized symplastic domain formed by mesophyll, bundle sheath and phloem parenchyma cells, and were not found in companion cell-sieve element complex. Simultaneously, formation of large central vacuoles in companion cells was noted. Restoration of organelle structures in assimilating cells and phloem parenchyma in 1-2 h after treatment was accompanied by enhancement of morphological changes in phloem elements and companion cells and signs of plasmolysis in the mesophyll cells. It was supposed that the two-phase character of changes in leaf organelle ultrastructure and photosynthesis might reflect duality of leaf cell response to nitrate ion. The rapid alterations of the structure can be coupled with direct influence of the anion on cell metabolism and(or) with signal-regulatory functions of oxidized nitrogen forms, while the slower ones reflect the result of suppression of photoassimilate export from leaves by the anion.

  18. Frontal Lobe Seizures

    Science.gov (United States)

    ... you're having signs or symptoms of a seizure. Call 911 or call for emergency medical help if you observe someone having a ... which seizure activity lasts much longer than usual. Seizures that last longer than ... emergency. Injury. The motions that occur during frontal lobe ...

  19. Rescue therapies for seizures.

    Science.gov (United States)

    Poukas, Valeriya S; Pollard, John R; Anderson, Christopher Todd

    2011-08-01

    Most medical therapies for epilepsy consist of daily (or multiple-daily) dose, fixed-schedule, pharmacologic oral agents. Despite adherence, many patients continue to experience seizures. Various products have been discovered, designed, and marketed to serve as seizure-abortant therapies. These agents can be administered rapidly, as a "rescue" therapy, once a clinical seizure or cluster of seizures starts. Rescue medications are given as needed in an attempt to disrupt progression of a given seizure, and forestall what would otherwise be a more prolonged or more severe clinical event. Seizure-abortants also serve to aid in the management of seizure emergencies, such as prolonged, repetitive seizures, or status epilepticus. These compounds are not appropriate for all patients. Nevertheless, they do provide therapeutic benefit to several groups of patients: 1) those who perceive the onset of their seizures and have time to perform a self-intervention, 2) patients' caregivers who administer the therapy when they witness the onset of an ictal event, and 3) patients who are in the midst of an out-of-the-hospital seizure emergency (a seizure cluster or status epilepticus). In this article we will review currently available and future rescue therapies for seizures: US Food and Drug Administration (FDA) approved and FDA nonapproved drugs, nonpharmacologic behavioral treatments, the vagus nerve stimulator and the NeuroPace RNS® System (Mountain View, CA).

  20. Seizure-induced miosis.

    Science.gov (United States)

    Sadek, Ahmed-Ramadan; Kirkham, Fenella; Barker, Simon; Gray, William P; Allen, David

    2011-12-01

    Ictal autonomic pupillary dilation is common; however, miosis is rare. We describe a case of focal seizures secondary to cortical dysplasia presenting with bilateral pupillary miosis, rendered seizure free by resective surgery. The seizure-onset zone was localized within the left middle parietal gyrus by intracranial electrographic recording. Seizure onset was coincident with focal left centroparietal fast spike activity on electroencephalography (EEG). A large region of the left frontocentral cortical dysplasia was demonstrated on magnetic resonance imaging (MRI). Complete resection of the area of cortical dysplasia and additional cortical regions of ictal activity, identified using intracranial EEG, rendered the patient seizure free. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  1. Thermospheric Data Assimilation

    Science.gov (United States)

    2016-05-05

    AFRL-AFOSR-VA-TR-2016-0193 Thermospheric Data Assimilation Tomoko Matsuo REGENTS OF THE UNIVERSITY OF COLORADO THE Final Report 05/05/2016...Thermospheric Data Assimilation 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0058 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dr. Tomoko...thermosphere-ionosphere first-principles model. An ensemble data assimilation procedure, constructed with the NCAR Data Assimilation Research Testbed

  2. The Assimilation of Envisat data (ASSET project

    Directory of Open Access Journals (Sweden)

    W. A. Lahoz

    2007-01-01

    Full Text Available This paper discusses the highlights of the EU-funded "Assimilation of Envisat data" (ASSET project, which has involved assimilation of Envisat atmospheric constituent and temperature data into systems based on Numerical Weather Prediction (NWP models and chemical transport models (CTMs. Envisat was launched in 2002 and is one of the largest Earth Observation (EO satellites ever built. It carries several sophisticated EO instruments providing insights into chemistry and dynamics of the atmosphere. In this paper we focus on the assimilation of temperature and constituents from Envisat. The overarching theme of the ASSET project has been to bring together experts from all aspects of the data assimilation problem. This has allowed ASSET to address several themes comprehensively: enhancement of NWP analyses by assimilation of research satellite data; studies of the distribution of stratospheric chemical species by assimilation of research satellite data into CTM systems; objective assessment of the quality of ozone analyses; studies of the spatial and temporal evolution of tropospheric pollutants; enhanced retrievals of Envisat data; and data archival and dissemination. Among the results from the ASSET project, many of which are firsts in their field, we can mention: a positive impact on NWP analyses from assimilation of height-resolved stratospheric humidity and temperature data, and assimilation of limb radiances; the extraction of temperature information from the assimilation of chemical species into CTMs; a first intercomparison between ozone assimilation systems; the extraction of information on tropospheric pollution from assimilation of Envisat data; and the large potential of the Envisat MIPAS dataset. This paper discusses these, often novel, developments and results. Finally, achievements of, and recommendations from, the ASSET project are presented.

  3. Data assimilation for the monitoring of continental surfaces

    OpenAIRE

    Jarlan, L.; Boulet, Gilles

    2014-01-01

    This chapter presents the basis of data assimilation by limiting the mathematical developments as much as possible. It emphasizes the data assimilation of remote sensing observations in land surface models, although the assimilation techniques presented can be applied to different kinds of dynamical models. The chapter considers three documents to be benchmarks in their respective fields for anyone who wishes to study them in greater depth. They are as follows: dynamic modeling of natural lan...

  4. Seizures induced by music.

    Science.gov (United States)

    Ogunyemi, A O; Breen, H

    1993-01-01

    Musicogenic epilepsy is a rare disorder. Much remains to be learned about the electroclinical features. This report describes a patient who has been followed at our institution for 17 years, and was investigated with long-term telemetered simultaneous video-EEG recordings. She began to have seizures at the age of 10 years. She experienced complex partial seizures, often preceded by elementary auditory hallucination and complex auditory illusion. The seizures occurred in relation to singing, listening to music or thinking about music. She also had occasional generalized tonic clonic seizures during sleep. There was no significant antecedent history. The family history was negative for epilepsy. The physical examination was unremarkable. CT and MRI scans of the brain were normal. During long-term simultaneous video-EEG recordings, clinical and electrographic seizure activities were recorded in association with singing and listening to music. Mathematical calculation, copying or viewing geometric patterns and playing the game of chess failed to evoke seizures.

  5. Seizure semiology and aging.

    Science.gov (United States)

    Silveira, Diosely C; Jehi, Lara; Chapin, Jessica; Krishnaiengar, Suparna; Novak, Eric; Foldvary-Schaefer, Nancy; Najm, Imad

    2011-02-01

    The incidence of epilepsy is high in older individuals. However, epilepsy in the elderly may be underdiagnosed and undertreated because of diagnostic difficulties. The main goal of this study was to determine whether seizure semiology differs between older and younger adults with epilepsy in the outpatient setting. Fifty patients with focal epilepsy aged 55 years and older and 50 patients aged between 18 and 45 years were included. Review of medical records contained detailed seizure description. There were no differences in seizure semiology between groups, except that subtle perceptions of transient confusion were seen in older patients but not in younger patients (P=0.0028). Older patients had less generalized motor seizures, but the differences between groups did not reach significance (P=0.01). Older patients may present with subtle symptoms of seizures characterized by brief periods of confusion, which may contribute to greater difficulty diagnosing seizures in the elderly. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Value and limitations of seizure semiology in localizing seizure onset.

    Science.gov (United States)

    So, Elson L

    2006-08-01

    Seizure semiology has been the foundation of clinical diagnosis of seizure disorders. This article discusses the value and the limitations of behavioral features of seizure episodes in localizing seizure onset. Studies have shown that some semiologic features of seizures are highly accurate in the hemispheric lateralization and lobar localization of seizures. There is good agreement between blinded reviewers in lateralizing video-recorded seizures in temporal lobe and extratemporal lobe epilepsies. However, seizure semiology alone should not be used to determine the site of seizure onset. Each semiologic feature may falsely localize seizure onset. Seizure semiology in some patients may signify the site of seizure propagation rather than origination. Moreover, seizure semiology may not be as reliable in multifocal epilepsies as it is in unifocal epilepsies. Many semiologic features of seizures of adults are often missing in seizures of children. Seizure semiology should be analyzed and integrated with EEG and neuroimaging data to localize the seizure focus. A sample of the recorded seizures should be shown to the patient's relatives or friends to verify that it is representative of habitual seizures.

  7. [Another seizure classification--Semiological Seizure Classification].

    Science.gov (United States)

    Lin, Ji-Ho; Kwan, Shang-Yeong; Wu, Dean; Su, Min-Shin; Yiu, Chun-Hing

    2004-09-01

    The International League Against Epilepsy (ILAE) introduced in 1981 a seizure classification based on clinical semiology, interictal EEG findings, and ictal EEG patterns. Such classification depends heavily on detailed electroclinical correlation. After 20 years' progress in epileptology, many clinicians have found it difficult to make a "definite" seizure diagnosis clinically without a series of electrophysiological examinations, particularly in the infants, and further advancement in epileptology has findings have made the previous classification inefficient. Lüders and colleagues have proposed a classification, Semiological Seizure Classification (SSC), based exclusively on ictal semiology, which was published in the official journal of ILAE-EPILEPSIA in 1998. The EEG, neuroimaging and other laboratory results should be analyzed separately and then integrated to define the epileptic syndromes. The seizure diagnosis is thus made through a "what-you-see-is-what-you-get" way. It has also provoked an extensive discussion about the necessity of this new classification. In this review, we present the original guideline, which has been used at The Cleveland Clinic Foundation for years, to introduce another method of epileptic seizure classification.

  8. Effective assimilation of global precipitation: simulation experiments

    Directory of Open Access Journals (Sweden)

    Guo-Yuan Lien

    2013-07-01

    Full Text Available Past attempts to assimilate precipitation by nudging or variational methods have succeeded in forcing the model precipitation to be close to the observed values. However, the model forecasts tend to lose their additional skill after a few forecast hours. In this study, a local ensemble transform Kalman filter (LETKF is used to effectively assimilate precipitation by allowing ensemble members with better precipitation to receive higher weights in the analysis. In addition, two other changes in the precipitation assimilation process are found to alleviate the problems related to the non-Gaussianity of the precipitation variable: (a transform the precipitation variable into a Gaussian distribution based on its climatological distribution (an approach that could also be used in the assimilation of other non-Gaussian observations and (b only assimilate precipitation at the location where at least some ensemble members have precipitation. Unlike many current approaches, both positive and zero rain observations are assimilated effectively. Observing system simulation experiments (OSSEs are conducted using the Simplified Parametrisations, primitivE-Equation DYnamics (SPEEDY model, a simplified but realistic general circulation model. When uniformly and globally distributed observations of precipitation are assimilated in addition to rawinsonde observations, both the analyses and the medium-range forecasts of all model variables, including precipitation, are significantly improved as compared to only assimilating rawinsonde observations. The effect of precipitation assimilation on the analyses is retained on the medium-range forecasts and is larger in the Southern Hemisphere (SH than that in the Northern Hemisphere (NH because the NH analyses are already made more accurate by the denser rawinsonde stations. These improvements are much reduced when only the moisture field is modified by the precipitation observations. Both the Gaussian transformation and

  9. Management of provoked seizure

    Directory of Open Access Journals (Sweden)

    Misra Usha

    2011-01-01

    Full Text Available A provoked seizure may be due to structural damage (resulting from traumatic brain injury, brain tumor, stroke, tuberculosis, or neurocysticercosis or due to metabolic abnormalities (such as alcohol withdrawal and renal or hepatic failure. This article is a part of the Guidelines for Epilepsy in India. This article reviews the problem of provoked seizure and its management and also provides recommendations based on currently available information. Seizure provoked by metabolic disturbances requires correction of the triggering factors. Benzodiazepines are recommended for treatment of seizure due to alcohol withdrawal; gabapentin for seizure seen in porphyria; and antiepileptic drugs (AED, that are not inducer of hepatic enzymes, in the seizures seen in hepatic dysfunction. In severe traumatic brain injury, with or without seizure, phenytoin (PHT may be given for 7 days. In ischemic or hemorrhagic stroke one may individualize the AED therapy. In cerebral venous sinus thrombosis (CVST, AED may be prescribed if there is seizure or computed tomographic (CT abnormalities or focal weakness; the treatment, in these cases, has to be continued for 1 year. Prophylactic AED is not recommended in cases of brain tumor and neurosurgical procedures and if patient is on an AED it can be stopped after 1 week.

  10. Genes, Seizures & Epilepsy

    Science.gov (United States)

    Goldman, Alica M.

    2006-01-01

    The chance that someone will develop any disease is influenced by heredity and environment. Epilepsy is not an exception. Everybody inherits a unique degree of susceptibility to seizures. About 3 percent of the United States population is prone to seizures and will get epilepsy at some point of their lives (1). Two thirds of the people with…

  11. Code blue: seizures.

    Science.gov (United States)

    Hoerth, Matthew T; Drazkowski, Joseph F; Noe, Katherine H; Sirven, Joseph I

    2011-06-01

    Eyewitnesses frequently perceive seizures as life threatening. If an event occurs on the hospital premises, a "code blue" can be called which consumes considerable resources. The purpose of this study was to determine the frequency and characteristics of code blue calls for seizures and seizure mimickers. A retrospective review of a code blue log from 2001 through 2008 identified 50 seizure-like events, representing 5.3% of all codes. Twenty-eight (54%) occurred in inpatients; the other 22 (44%) events involved visitors or employees on the hospital premises. Eighty-six percent of the events were epileptic seizures. Seizure mimickers, particularly psychogenic nonepileptic seizures, were more common in the nonhospitalized group. Only five (17.9%) inpatients had a known diagnosis of epilepsy, compared with 17 (77.3%) of the nonhospitalized patients. This retrospective survey provides insights into how code blues are called on hospitalized versus nonhospitalized patients for seizure-like events. Copyright © 2011. Published by Elsevier Inc.

  12. Management of provoked seizure.

    Science.gov (United States)

    Misra, Usha Kant; Kalita, Jayantee

    2011-01-01

    A provoked seizure may be due to structural damage (resulting from traumatic brain injury, brain tumor, stroke, tuberculosis, or neurocysticercosis) or due to metabolic abnormalities (such as alcohol withdrawal and renal or hepatic failure). This article is a part of the Guidelines for Epilepsy in India. This article reviews the problem of provoked seizure and its management and also provides recommendations based on currently available information. Seizure provoked by metabolic disturbances requires correction of the triggering factors. Benzodiazepines are recommended for treatment of seizure due to alcohol withdrawal; gabapentin for seizure seen in porphyria; and antiepileptic drugs (AED), that are not inducer of hepatic enzymes, in the seizures seen in hepatic dysfunction. In severe traumatic brain injury, with or without seizure, phenytoin (PHT) may be given for 7 days. In ischemic or hemorrhagic stroke one may individualize the AED therapy. In cerebral venous sinus thrombosis (CVST), AED may be prescribed if there is seizure or computed tomographic (CT) abnormalities or focal weakness; the treatment, in these cases, has to be continued for 1 year. Prophylactic AED is not recommended in cases of brain tumor and neurosurgical procedures and if patient is on an AED it can be stopped after 1 week.

  13. Grand Mal Seizure

    Science.gov (United States)

    ... Withdrawal syndromes Using or withdrawing from drugs, including alcohol Risk factors Risk factors for grand mal seizures include: ... that affect electrolyte balance Illicit drug use Heavy alcohol use ... or others. You might be at risk of: Falling. If you fall during a seizure, ...

  14. Seizures: emergency neuroimaging.

    Science.gov (United States)

    Hess, Christopher P; Barkovich, A James

    2010-11-01

    The various findings observed on computed tomography (CT) and magnetic resonance (MR) imaging examinations in patients with seizures reflect the variety of different causes that give rise to this common neurologic symptom. In the emergency setting, CT is most valuable in its ability to accurately identify acute abnormalities that require emergent medical or surgical treatment. MR imaging, by contrast, is usually reserved for patients with recurrent or refractory seizures. The accurate interpretation of either modality requires familiarity with how seizures are classified clinically, the most common presenting features of different causes for seizures, the relevant neuroanatomy, and the imaging manifestations of both common and uncommon causes of seizures and epilepsy. Of particular practical importance to the radiologist is the ability to recognize (1) the most common findings in patients with recurrent seizures and (2) potentially reversible causes for seizures that require prompt intervention to avoid or minimize permanent brain injury. This article surveys a variety of different causes for seizures and epilepsy, focusing on specific clinical features that can help to refine differential diagnosis, and on imaging findings characteristic of different disorders. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Seizures in multiple sclerosis

    NARCIS (Netherlands)

    Koch, Marcus; Uyttenboogaart, Maarten; Polman, Susan; De Keyser, Jacques

    Seizures have long been recognized to be part of the disease spectrum of multiple sclerosis (MS). While they occur in only a minority of patients with MS, epileptic seizures can have serious consequences. The treatment of MS can be epileptogenic, and antiepileptic treatment can conversely worsen the

  16. Error dynamics in a coastal configuration of NEMO using stochastic modeling: first steps towards Data Assimilation in the Bay of Biscay

    Science.gov (United States)

    Quattrocchi, G.; Testut, C.-E.; Ayoub, N.; De Mey, P.; Reffray, G.; Chanut, J.; Drillet, Y.

    2012-04-01

    At present, several high-resolution models are widely used in coastal ocean configuration with prediction purposes. In this context the choice of the ad hoc data assimilation (DA) method, that will ensure the "best" estimate of the ocean state through a combination of model forecast and observations, is decisive and it needs to be assessed on a case-by-case basis. The design of a DA system, based on the Ensemble Kalman Filter and the ocean model NEMO, is currently involving the french research teams of MERCATOR-OCEAN and of LEGOS (CNRS, Toulouse), within the MyOcean project. As a key step towards DA, we present sensitive experiments devoted to the evaluation of the model errors and their dynamic, primarily due to the uncertainties in the atmospheric forcing. More particularly, the ensemble experiments are carried out in the ocean model NEMO, in its coastal configuration in the Bay of Biscay, and they are performed within a winter period ranging from 01.12.2007 to 29.02.2008 (initial conditions are provided at 01.12.2007 by a longer reference run). For each member of the ensemble and every five days of integration of the ocean model, a perturbed wind anomaly, composed by a linear combination of five random normally distributed values and five temporal and spatial EOFs, is added to the unperturbed wind. As the result of such experiences the errors evolution is depicted by the analysis of high-order statistical moments as well as the computation of the error covariance and the representers. Comparisons to other stochastic modeling experiments (by LEGOS/CNRS, PREVIMER/IFREMER) are carried out with the aim to better understand the observed error subspace structures and with the common objective of accompany the development of operational oceanography in coastal areas and more specifically in the Bay of Biscay.

  17. Reliability of seizure semiology in patients with 2 seizure foci.

    Science.gov (United States)

    Rathke, Kevin M; Schäuble, Barbara; Fessler, A James; So, Elson L

    2011-06-01

    To determine whether seizure semiology is reliable in localizing and distinguishing seizures at 2 independent brain foci in the same patient. Two masked reviewers localized seizures from 2 foci by their clinical semiology and intracranial electroencephalograms (EEGs). Epilepsy monitoring unit of referral comprehensive epilepsy program. Seventeen consecutive patients (51 seizures) with sufficient video and intracranial EEG data were identified by reviewing medical records of 366 patients older than 10 years. The primary outcome measures were interobserver agreement between the 2 masked reviewers; the proportion of seizures localized by semiology; the proportion of localized seizures concordant with intracranial EEG localization; and comparison between concordant and nonconcordant seizures in latency of intracranial EEG seizure spread. Interobserver agreement was 41% (κ score, 0.16). Only 30 of 51 seizures (59%) were localized by seizure semiology. The focus localized by semiology was concordant with the location of intracranial EEG seizure onset in 16 of 30 seizures (53%). No significant difference was observed between concordant and nonconcordant seizures in relation to the speed with which the EEG discharge spread from the location of seizure onset to another lobar region (P = .09, Wilcoxon rank sum test). Clinical seizure semiology is not as useful as intracranial EEG in localizing seizure onset in patients with dual seizure foci.

  18. Epilepsy after Febrile Seizures

    DEFF Research Database (Denmark)

    Seinfeld, S. A.; Pellock, J M; Kjeldsen, Lone Marianne Juel

    2016-01-01

    Background A history of complex febrile seizures can increase the risk of epilepsy, but the role of genetic factors is unclear. This analysis evaluated the relationship between febrile seizures and epilepsy. Methods Information on the history of seizures was obtained by a questionnaire from twin...... epilepticus. There were 78 twins who developed epilepsy. The highest rate of epilepsy (22.2%) occurred in the febrile status epilepticus group. Concordance was highest in simple group. Conclusion A twin with febrile status epilepticus is at the highest risk of developing epilepsy, but simple febrile seizures...... and emotional burden. It is currently not possible to accurately identify which children will develop recurrent febrile seizures, epilepsy, or neuropsychological comorbidities. © 2016 Elsevier Inc. All rights reserved....

  19. Frontal Lobe Seizures

    Science.gov (United States)

    ... tumors, stroke, infection or traumatic injuries — in the brain's frontal lobes. Frontal lobe seizures are also associated with a rare inherited disorder called autosomal dominant nocturnal frontal lobe epilepsy. If one of your ...

  20. Temporal Lobe Seizure

    Science.gov (United States)

    ... pregnancy Temporal lobe seizure Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  1. Temporal Lobe Seizure

    Science.gov (United States)

    ... functions, including having odd feelings — such as euphoria, deja vu or fear. During a temporal lobe seizure, you ... include: A sudden sense of unprovoked fear A deja vu experience — a feeling that what's happening has happened ...

  2. Assortative mixing in functional brain networks during epileptic seizures

    Science.gov (United States)

    Bialonski, Stephan; Lehnertz, Klaus

    2013-09-01

    We investigate assortativity of functional brain networks before, during, and after one-hundred epileptic seizures with different anatomical onset locations. We construct binary functional networks from multi-channel electroencephalographic data recorded from 60 epilepsy patients; and from time-resolved estimates of the assortativity coefficient, we conclude that positive degree-degree correlations are inherent to seizure dynamics. While seizures evolve, an increasing assortativity indicates a segregation of the underlying functional network into groups of brain regions that are only sparsely interconnected, if at all. Interestingly, assortativity decreases already prior to seizure end. Together with previous observations of characteristic temporal evolutions of global statistical properties and synchronizability of epileptic brain networks, our findings may help to gain deeper insights into the complicated dynamics underlying generation, propagation, and termination of seizures.

  3. Fibromyalgia and seizures.

    Science.gov (United States)

    Tatum, William O; Langston, Michael E; Acton, Emily K

    2016-06-01

    The purpose of this case-matched study was to determine how frequently fibromyalgia is associated with different paroxysmal neurological disorders and explore the utility of fibromyalgia as a predictor for the diagnosis of psychogenic non-epileptic seizures. The billing diagnosis codes of 1,730 new, non-selected patient encounters were reviewed over a three-year period for an epileptologist in a neurology clinic to identify all patients with historical diagnoses of fibromyalgia. The frequency with which epileptic seizures, psychogenic non-epileptic seizures, and physiological non-epileptic events were comorbid with fibromyalgia was assessed. Age and gender case-matched controls were used for a between-group comparison. Wilcoxon tests were used to analyse interval data, and Chi-square was used to analyse categorical data (pFibromyalgia was retrospectively identified in 95/1,730 (5.5%) patients in this cohort. Females represented 95% of the fibromyalgia sample (age: 53 years; 95% CI: 57, 51). Forty-three percent of those with fibromyalgia had a non-paroxysmal, neurological primary clinical diagnosis, most commonly chronic pain. Paroxysmal events were present in 57% of fibromyalgia patients and 54% of case-matched controls. Among patients with fibromyalgia and paroxysmal disorders, 11% had epileptic seizures, 74% had psychogenic non-epileptic seizures, and 15% had physiological non-epileptic events, compared to case-matched controls with 37% epileptic seizures, 51% psychogenic non-epileptic events, and 12% physiological non-epileptic events (p = 0.009). Fibromyalgia was shown to be a predictor for the diagnosis of psychogenic non-epileptic seizures in patients with undifferentiated paroxysmal spells. However, our results suggest that the specificity and sensitivity of fibromyalgia as a marker for psychogenic non-epileptic seizures in a mixed general neurological population of patients is less than previously described.

  4. Seizures Induced by Music

    Directory of Open Access Journals (Sweden)

    A. O. Ogunyemi

    1993-01-01

    Full Text Available Musicogenic epilepsy is a rare disorder. Much remains to be learned about the electroclinical features. This report describes a patient who has been followed at our institution for 17 years, and was investigated with long-term telemetered simultaneous video-EEG recordings. She began to have seizures at the age of 10 years. She experienced complex partial seizures, often preceded by elementary auditory hallucination and complex auditory illusion. The seizures occurred in relation to singing, listening to music or thinking about music. She also had occasional generalized tonic clonic seizures during sleep. There was no significant antecedent history. The family history was negative for epilepsy. The physical examination was unremarkable. CT and MRI scans of the brain were normal. During long-term simultaneous video-EEG recordings, clinical and electrographic seizure activities were recorded in association with singing and listening to music. Mathematical calculation, copying or viewing geometric patterns and playing the game of chess failed to evoke seizures.

  5. Displacement Data Assimilation

    Science.gov (United States)

    Restrepo, J. M.; Rosenthal, S.; Venkataramani, S.

    2013-05-01

    Geometric corrections are blended with nonlinear/non-Gaussian estimation methods to produced improved data assimilation outcomes on problems where features are critical. Problems of this sort are the estimation of hurricane tracks, tracking jet meandering, front propagation, among many others. The geometric correction is made possible by a data preserving map. It makes corrections on phase, primarily, as well as in the amplitude. The displacement assimilation is embedded in the analysis stage of a nonlinear/non-Gaussian Bayesian data assimilation scheme, such as the path integral method. In addition to showing how the method improves upon the results, as compared to more standard methodologies.

  6. Quantitative analysis of surface electromyography: Biomarkers for convulsive seizures.

    Science.gov (United States)

    Beniczky, Sándor; Conradsen, Isa; Pressler, Ronit; Wolf, Peter

    2016-08-01

    Muscle activity during seizures is in electroencephalographical (EEG) praxis often considered an irritating artefact. This article discusses ways by surface electromyography (EMG) to turn it into a valuable tool of epileptology. Muscles are in direct synaptic contact with motor neurons. Therefore, EMG signals provide direct information about the electric activity in the motor cortex. Qualitative analysis of EMG has traditionally been a part of the long-term video-EEG recordings. Recent development in quantitative analysis of EMG signals yielded valuable information on the pathomechanisms of convulsive seizures, demonstrating that it was different from maximal voluntary contraction, and different from convulsive psychogenic non-epileptic seizures. Furthermore, the tonic phase of the generalised tonic-clonic seizures (GTCS) proved to have different quantitative features than tonic seizures. The high temporal resolution of EMG allowed detailed characterisation of temporal dynamics of the GTCS, suggesting that the same inhibitory mechanisms that try to prevent the build-up of the seizure activity, contribute to ending the seizure. These findings have clinical implications: the quantitative EMG features provided the pathophysiologic substrate for developing neurophysiologic biomarkers that accurately identify GTCS. This proved to be efficient both for seizure detection and for objective, automated distinction between convulsive and non-convulsive epileptic seizures. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  7. Altimeter data assimilation in the tropical Indian Ocean using water ...

    Indian Academy of Sciences (India)

    Altimeter data have been assimilated in an ocean general circulation model using the water property conserving scheme. ... 2003). Keywords. Data assimilation; altimeter data; ocean general circulation model; thermocline depth; sea surface temperature; .... converting wind to wind stress using bulk aero- dynamic formula.

  8. An Ensemble Algorithm Based Component for Geomagnetic Data Assimilation

    Directory of Open Access Journals (Sweden)

    Zhibin Sun and Weijia Kuang

    2015-01-01

    Full Text Available Geomagnetic data assimilation is one of the most recent developments in geomagnetic studies. It combines geodynamo model outputs and surface geomagnetic observations to provide more accurate estimates of the core dynamic state and provide accurate geomagnetic secular variation forecasting. To facilitate geomagnetic data assimilation studies, we develop a stand-alone data assimilation component for the geomagnetic community. This component is used to calculate the forecast error covariance matrices and the gain matrix from a given geodynamo solution, which can then be used for sequential geomagnetic data assimilation. This component is very flexible and can be executed independently. It can also be easily integrated with arbitrary dynamo models.

  9. Tuberculoma Induced Seizures

    Directory of Open Access Journals (Sweden)

    R. James Salway

    2015-10-01

    Full Text Available Seizures in human immunodeficiency virus (HIV patients can be caused by a wide variety of opportunistic infections, and, especially in developing countries, tuberculosis (TB should be high on the differential. In India, TB is the most common opportunistic infection in HIV and it can have several different central nervous system manifestations, including intracranial tuberculomas. In this case, an HIV patient presenting with new-onset seizure and fever was diagnosed with tuberculous meningitis and multiple intracranial tuberculomas. The patient received standard TB medications, steroids, and anticonvulsants in the emergency department and was admitted for further care.

  10. Epileptic seizures: Quakes of the brain?

    Science.gov (United States)

    Osorio, Ivan; Frei, Mark G.; Sornette, Didier; Milton, John; Lai, Ying-Cheng

    2010-08-01

    A dynamical analogy supported by five scale-free statistics (the Gutenberg-Richter distribution of event sizes, the distribution of interevent intervals, the Omori and inverse Omori laws, and the conditional waiting time until the next event) is shown to exist between two classes of seizures (“focal” in humans and generalized in animals) and earthquakes. Increments in excitatory interneuronal coupling in animals expose the system’s dependence on this parameter and its dynamical transmutability: moderate increases lead to power-law behavior of seizure energy and interevent times, while marked ones to scale-free (power-law) coextensive with characteristic scales and events. The coextensivity of power law and characteristic size regimes is predicted by models of coupled heterogeneous threshold oscillators of relaxation and underscores the role of coupling strength in shaping the dynamics of these systems.

  11. Data assimilation a mathematical introduction

    CERN Document Server

    Law, Kody; Zygalakis, Konstantinos

    2015-01-01

    This book provides a systematic treatment of the mathematical underpinnings of work in data assimilation, covering both theoretical and computational approaches. Specifically the authors develop a unified mathematical framework in which a Bayesian formulation of the problem provides the bedrock for the derivation, development and analysis of algorithms; the many examples used in the text, together with the algorithms which are introduced and discussed, are all illustrated by the MATLAB software detailed in the book and made freely available online. The book is organized into nine chapters: the first contains a brief introduction to the mathematical tools around which the material is organized; the next four are concerned with discrete time dynamical systems and discrete time data; the last four are concerned with continuous time dynamical systems and continuous time data and are organized analogously to the corresponding discrete time chapters. This book is aimed at mathematical researchers interested in a sy...

  12. Seizure ending signs in patients with dyscognitive focal seizures.

    Science.gov (United States)

    Gavvala, Jay R; Gerard, Elizabeth E; Macken, Mícheál; Schuele, Stephan U

    2015-09-01

    Signs indicating the end of a focal seizure with loss of awareness and/or responsiveness but without progression to focal or generalized motor symptoms are poorly defined and can be difficult to determine. Not recognizing the transition from ictal to postictal behaviour can affect seizure reporting accuracy by family members and may lead to delayed or a lack of examination during EEG monitoring, erroneous seizure localization and inadequate medical intervention for prolonged seizure duration. Our epilepsy monitoring unit database was searched for focal seizures without secondary generalization for the period from 2007 to 2011. The first focal seizure in a patient with loss of awareness and/or responsiveness and/or behavioural arrest, with or without automatisms, was included. Seizures without objective symptoms or inadequate video-EEG quality were excluded. A total of 67 patients were included, with an average age of 41.7 years. Thirty-six of the patients had seizures from the left hemisphere and 29 from the right. All patients showed an abrupt change in motor activity and resumed contact with the environment as a sign of clinical seizure ending. Specific ending signs (nose wiping, coughing, sighing, throat clearing, or laughter) were seen in 23 of 47 of temporal lobe seizures and 7 of 20 extra-temporal seizures. Seizure ending signs are often subtle and the most common finding is a sudden change in motor activity and resumption of contact with the environment. More distinct signs, such as nose wiping, coughing or throat clearing, are not specific to temporal lobe onset. A higher proportion of seizures during sleep went unexamined, compared to those during wakefulness. This demonstrates that seizure semiology can be very subtle and arousals from sleep during monitoring should alert staff. Patient accounts of seizure frequency appear to be unreliable and witness reports need to be taken into account. [Published with video sequences].

  13. Data assimilation the ensemble Kalman filter

    CERN Document Server

    Evensen, Geir

    2007-01-01

    Data Assimilation comprehensively covers data assimilation and inverse methods, including both traditional state estimation and parameter estimation. This text and reference focuses on various popular data assimilation methods, such as weak and strong constraint variational methods and ensemble filters and smoothers. It is demonstrated how the different methods can be derived from a common theoretical basis, as well as how they differ and/or are related to each other, and which properties characterize them, using several examples. Rather than emphasize a particular discipline such as oceanography or meteorology, it presents the mathematical framework and derivations in a way which is common for any discipline where dynamics is merged with measurements. The mathematics level is modest, although it requires knowledge of basic spatial statistics, Bayesian statistics, and calculus of variations. Readers will also appreciate the introduction to the mathematical methods used and detailed derivations, which should b...

  14. Absence seizure in the elderly

    African Journals Online (AJOL)

    2011-06-15

    Jun 15, 2011 ... seizures or myoclonus,[3] as well as frontal lobe abnormalities such as cortical atrophy.[4]. Absence status epilepticus absence seizure (AS) is a prolonged, generalized, and nonconvulsive seizure characterized by more or less severe impairment of consciousness, at times associated with other.

  15. Terminology of psychogenic nonepileptic seizures.

    Science.gov (United States)

    Brigo, Francesco; Igwe, Stanley C; Ausserer, Harald; Nardone, Raffaele; Tezzon, Frediano; Bongiovanni, Luigi Giuseppe; Tinazzi, Michele; Trinka, Eugen

    2015-03-01

    Several different terms have been used to describe "psychogenic nonepileptic seizures" (PNES) in the literature. In this study, we evaluated the most common English terms used to describe PNES on Google and in PubMed using multiple search terms (https://www.google.com and http://www.ncbi.nlm.nih.gov/pubmed). The information prevalence of the five terms most frequently used to refer to PNES in PubMed were: psychogenic non(-)epileptic seizure(s), followed by pseudo(-)seizure(s), non(-)epileptic seizure(s), psychogenic seizure(s), and non(-)epileptic event(s). The five most frequently adopted terms to describe PNES in Google were: psychogenic non(-)epileptic seizure(s), followed by non(-)epileptic event(s), psychogenic attack(s), non(-)epileptic attack(s), and psychogenic non(-)epileptic attack(s). The broad spectrum of synonyms used to refer to PNES in the medical literature reflects a lack of internationally accepted, uniform terminology for PNES. In addition to "seizure(s)," lay people use the word "attack(s)" to describe PNES. Although considered obsolete, some terms, e.g., pseudoseizure(s), are still used in the recent medical literature. Adopting a uniform terminology to describe PNES could facilitate communication between epileptologists, physicians without specific expertise in epilepsy, and patients. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

  16. Comparison of large-scale dynamical variability in the extratropical stratosphere among the JRA-55 family data sets: impacts of assimilation of observational data in JRA-55 reanalysis data

    Science.gov (United States)

    Taguchi, Masakazu

    2017-09-01

    This study compares large-scale dynamical variability in the extratropical stratosphere, such as major stratospheric sudden warmings (MSSWs), among the Japanese 55-year Reanalysis (JRA-55) family data sets. The JRA-55 family consists of three products: a standard product (STDD) of the JRA-55 reanalysis data and two sub-products of JRA-55C (CONV) and JRA-55AMIP (AMIP). CONV assimilates only conventional surface and upper-air observations without assimilation of satellite observations, whereas AMIP runs the same numerical weather prediction model without assimilation of observational data. A comparison of the occurrence of MSSWs in Northern Hemisphere (NH) winter shows that, compared to STDD, CONV delays several MSSWs by 1 to 4 days and also misses a few MSSWs. CONV also misses the Southern Hemisphere (SH) MSSW in September 2002. AMIP shows significantly fewer MSSWs in Northern Hemisphere winter and especially lacks MSSWs of the high aspect ratio of the polar vortex in which the vortex is highly stretched or split. A further examination of daily geopotential height differences between STDD and CONV reveals occasional peaks in both hemispheres that are separated from MSSWs. The delayed and missed MSSW cases have smaller height differences in magnitude than such peaks. The height differences for those MSSWs include large contributions from the zonal component, which reflects underestimations in the weakening of the zonal mean polar night jet in CONV. We also explore strong planetary wave forcings and associated polar vortex weakenings for STDD and AMIP. We find a lower frequency of strong wave forcings and weaker vortex responses to such wave forcings in AMIP, consistent with the lower MSSW frequency.

  17. Contribution of Bicarbonate Assimilation to Carbon Pool Dynamics in the Deep Mediterranean Sea and Cultivation of Actively Nitrifying and CO2-Fixing Bathypelagic Prokaryotic Consortia.

    Science.gov (United States)

    La Cono, Violetta; Ruggeri, Gioachino; Azzaro, Maurizio; Crisafi, Francesca; Decembrini, Franco; Denaro, Renata; La Spada, Gina; Maimone, Giovanna; Monticelli, Luis S; Smedile, Francesco; Giuliano, Laura; Yakimov, Michail M

    2018-01-01

    Covering two-thirds of our planet, the global deep ocean plays a central role in supporting life on Earth. Among other processes, this biggest ecosystem buffers the rise of atmospheric CO 2 . Despite carbon sequestration in the deep ocean has been known for a long time, microbial activity in the meso- and bathypelagic realm via the " assimilation of bicarbonate in the dark " (ABD) has only recently been described in more details. Based on recent findings, this process seems primarily the result of chemosynthetic and anaplerotic reactions driven by different groups of deep-sea prokaryoplankton. We quantified bicarbonate assimilation in relation to total prokaryotic abundance, prokaryotic heterotrophic production and respiration in the meso- and bathypelagic Mediterranean Sea. The measured ABD values, ranging from 133 to 370 μg C m -3 d -1 , were among the highest ones reported worldwide for similar depths, likely due to the elevated temperature of the deep Mediterranean Sea (13-14°C also at abyssal depths). Integrated over the dark water column (≥200 m depth), bicarbonate assimilation in the deep-sea ranged from 396 to 873 mg C m -2 d -1 . This quantity of produced de novo organic carbon amounts to about 85-424% of the phytoplankton primary production and covers up to 62% of deep-sea prokaryotic total carbon demand. Hence, the ABD process in the meso- and bathypelagic Mediterranean Sea might substantially contribute to the inorganic and organic pool and significantly sustain the deep-sea microbial food web. To elucidate the ABD key-players, we established three actively nitrifying and CO 2 -fixing prokaryotic enrichments. Consortia were characterized by the co-occurrence of chemolithoautotrophic Thaumarchaeota and chemoheterotrophic proteobacteria. One of the enrichments, originated from Ionian bathypelagic waters (3,000 m depth) and supplemented with low concentrations of ammonia, was dominated by the Thaumarchaeota "low-ammonia-concentration" deep-sea ecotype

  18. Data Assimilation to Estimate the Water Level of River

    Science.gov (United States)

    Apriliani, Erna; Hanafi, Lukman; Imron, Chairul

    2017-09-01

    Data assimilation is an estimation method for stochastic dynamic system by combining the mathematical model with measurement data. Water level and velocity of river are stochastic dynamic system, and it is important to estimate the water level and velocity of river flow to reduce flood risk disaster. Here, we estimate the water level and velocity of river flow by using data assimilation specially Kalman filter and Ensemble Kalman filter. We define mathematical model of river flow, discretize and do simulation by Kalman filter and Ensemble Kalman filter. In data assimilation, we forecast the water level and velocity by using mathematical model and based on the measurement data, the correction of forecasting is made.

  19. Widespread EEG changes precede focal seizures.

    Directory of Open Access Journals (Sweden)

    Piero Perucca

    Full Text Available The process by which the brain transitions into an epileptic seizure is unknown. In this study, we investigated whether the transition to seizure is associated with changes in brain dynamics detectable in the wideband EEG, and whether differences exist across underlying pathologies. Depth electrode ictal EEG recordings from 40 consecutive patients with pharmacoresistant lesional focal epilepsy were low-pass filtered at 500 Hz and sampled at 2,000 Hz. Predefined EEG sections were selected immediately before (immediate preictal, and 30 seconds before the earliest EEG sign suggestive of seizure activity (baseline. Spectral analysis, visual inspection and discrete wavelet transform were used to detect standard (delta, theta, alpha, beta and gamma and high-frequency bands (ripples and fast ripples. At the group level, each EEG frequency band activity increased significantly from baseline to the immediate preictal section, mostly in a progressive manner and independently of any modification in the state of vigilance. Preictal increases in each frequency band activity were widespread, being observed in the seizure-onset zone and lesional tissue, as well as in remote regions. These changes occurred in all the investigated pathologies (mesial temporal atrophy/sclerosis, local/regional cortical atrophy, and malformations of cortical development, but were more pronounced in mesial temporal atrophy/sclerosis. Our findings indicate that a brain state change with distinctive features, in the form of unidirectional changes across the entire EEG bandwidth, occurs immediately prior to seizure onset. We postulate that these changes might reflect a facilitating state of the brain which enables a susceptible region to generate seizures.

  20. Widespread EEG Changes Precede Focal Seizures

    Science.gov (United States)

    Perucca, Piero; Dubeau, François; Gotman, Jean

    2013-01-01

    The process by which the brain transitions into an epileptic seizure is unknown. In this study, we investigated whether the transition to seizure is associated with changes in brain dynamics detectable in the wideband EEG, and whether differences exist across underlying pathologies. Depth electrode ictal EEG recordings from 40 consecutive patients with pharmacoresistant lesional focal epilepsy were low-pass filtered at 500 Hz and sampled at 2,000 Hz. Predefined EEG sections were selected immediately before (immediate preictal), and 30 seconds before the earliest EEG sign suggestive of seizure activity (baseline). Spectral analysis, visual inspection and discrete wavelet transform were used to detect standard (delta, theta, alpha, beta and gamma) and high-frequency bands (ripples and fast ripples). At the group level, each EEG frequency band activity increased significantly from baseline to the immediate preictal section, mostly in a progressive manner and independently of any modification in the state of vigilance. Preictal increases in each frequency band activity were widespread, being observed in the seizure-onset zone and lesional tissue, as well as in remote regions. These changes occurred in all the investigated pathologies (mesial temporal atrophy/sclerosis, local/regional cortical atrophy, and malformations of cortical development), but were more pronounced in mesial temporal atrophy/sclerosis. Our findings indicate that a brain state change with distinctive features, in the form of unidirectional changes across the entire EEG bandwidth, occurs immediately prior to seizure onset. We postulate that these changes might reflect a facilitating state of the brain which enables a susceptible region to generate seizures. PMID:24260523

  1. [Post traumatic partial seizures].

    Science.gov (United States)

    Carvajal, P; Almárcegui, C; Pablo, M J; Peralta, P; Bernal, M; Valdizán, J R

    Post traumatic epilepsy represents 4% of the prevalence of the disorder and is one of the sequelas which is most difficult to prevent. Risk factors have been described to predict the appearance of seizures. A seven year old boy with a severe head injury was admitted to the Intensive Care Unit. On neuroimaging studies there were multiple foci of contusion, mainly in the left hemisphere, and blood in the III and IV ventricles and frontal horn of the left lateral ventricle. The patient had severe sequelae of head injury with a right spastic hemiplegia and hemiparesia with hypertony of the left side, together with complete blindness of both eyes due to bilateral atrophy of the optic nerve. Serial EEG were done, in which a recording showed alternating periods of hypervoltage grapho elements superimposed on a trace of very low voltage, with continuous activity of low voltage and low frequency. There were no grapho elements with acute morphology. However, the patient had a first partial seizure a year and a half after his head injury. On the EEG an epileptogenic focus was identified in the left hemisphere. Within two years of his head injury he had seven seizures. He had not received prophylactic antiepileptic treatment after the head injury. We report a case of epilepsy secondary to a head injury, in which the first seizure occurred one and a half years after injury. In view of the risk factors, we discuss whether prophylactic anti epileptic treatment might have been beneficial.

  2. Seizures and Teens: The Impact of Seizures and Epilepsy on Families

    Science.gov (United States)

    Weinstein, Sandra Cushner

    2007-01-01

    When a teenager or child of any age develops seizures, the impact on the family can be enormous. Worries and fears may affect everyone, and left untreated, crises can occur too easily. This article explores the way that epilepsy can affect family dynamics. Common factors that may contribute to family stress and patterns of coping will be…

  3. Optimality in Data Assimilation

    Science.gov (United States)

    Nearing, Grey; Yatheendradas, Soni

    2016-04-01

    It costs a lot more to develop and launch an earth-observing satellite than it does to build a data assimilation system. As such, we propose that it is important to understand the efficiency of our assimilation algorithms at extracting information from remote sensing retrievals. To address this, we propose that it is necessary to adopt completely general definition of "optimality" that explicitly acknowledges all differences between the parametric constraints of our assimilation algorithm (e.g., Gaussianity, partial linearity, Markovian updates) and the true nature of the environmetnal system and observing system. In fact, it is not only possible, but incredibly straightforward, to measure the optimality (in this more general sense) of any data assimilation algorithm as applied to any intended model or natural system. We measure the information content of remote sensing data conditional on the fact that we are already running a model and then measure the actual information extracted by data assimilation. The ratio of the two is an efficiency metric, and optimality is defined as occurring when the data assimilation algorithm is perfectly efficient at extracting information from the retrievals. We measure the information content of the remote sensing data in a way that, unlike triple collocation, does not rely on any a priori presumed relationship (e.g., linear) between the retrieval and the ground truth, however, like triple-collocation, is insensitive to the spatial mismatch between point-based measurements and grid-scale retrievals. This theory and method is therefore suitable for use with both dense and sparse validation networks. Additionally, the method we propose is *constructive* in the sense that it provides guidance on how to improve data assimilation systems. All data assimilation strategies can be reduced to approximations of Bayes' law, and we measure the fractions of total information loss that are due to individual assumptions or approximations in the

  4. Emergence of semiology in epileptic seizures.

    Science.gov (United States)

    Chauvel, Patrick; McGonigal, Aileen

    2014-09-01

    clinical expression, as evidenced, for example, by studies of ictal fear-related behavior (decorrelation of activity between structures inducing "release" phenomena) and of déjà vu (increased synchronization). Studies of functional coupling within networks underlying complex ictal behavior indicate that the clinical semiology of a given seizure depends upon neither the anatomical origin of ictal discharge nor the target areas of its propagation alone but on the dynamic interaction between these. Careful mapping of the ictal network in its full spread offers essential information as to the localization of seizure onset, by deducing that a given network configuration could only be generated by a given area or group of areas. Copyright © 2013. Published by Elsevier Inc.

  5. Benzodiazepine withdrawal seizures and management.

    Science.gov (United States)

    Hu, Xiaohong

    2011-02-01

    Since the first report of benzodiazepine withdrawal seizure in 1961, many case reports have followed. Withdrawal seizures have occurred with short, medium, and long halflife benzodiazepine, if discontinued abruptly. Withdrawal seizures usually occur in patients who have been taking these medications for long periods of time and at high doses. Seizures have also been reported with less than 15 days of use and at therapeutic dosage. Almost all the withdrawal seizures reported were grand mal seizures. The severity of seizures range from a single episode to coma and death. Benzodiazepine dose tapering can be done faster in a hospital setting in high-dose abusers, but must be done more slowly in the outpatient setting in therapeutic dosage users.

  6. Brain State Is a Major Factor in Preseizure Hippocampal Network Activity and Influences Success of Seizure Intervention

    Science.gov (United States)

    Ewell, Laura A.; Liang, Liang; Armstrong, Caren; Soltész, Ivan; Leutgeb, Stefan

    2015-01-01

    Neural dynamics preceding seizures are of interest because they may shed light on mechanisms of seizure generation and could be predictive. In healthy animals, hippocampal network activity is shaped by behavioral brain state and, in epilepsy, seizures selectively emerge during specific brain states. To determine the degree to which changes in network dynamics before seizure are pathological or reflect ongoing fluctuations in brain state, dorsal hippocampal neurons were recorded during spontaneous seizures in a rat model of temporal lobe epilepsy. Seizures emerged from all brain states, but with a greater likelihood after REM sleep, potentially due to an observed increase in baseline excitability during periods of REM compared with other brains states also characterized by sustained theta oscillations. When comparing the firing patterns of the same neurons across brain states associated with and without seizures, activity dynamics before seizures followed patterns typical of the ongoing brain state, or brain state transitions, and did not differ until the onset of the electrographic seizure. Next, we tested whether disparate activity patterns during distinct brain states would influence the effectiveness of optogenetic curtailment of hippocampal seizures in a mouse model of temporal lobe epilepsy. Optogenetic curtailment was significantly more effective for seizures preceded by non-theta states compared with seizures that emerged from theta states. Our results indicate that consideration of behavioral brain state preceding a seizure is important for the appropriate interpretation of network dynamics leading up to a seizure and for designing effective seizure intervention. SIGNIFICANCE STATEMENT Hippocampal single-unit activity is strongly shaped by behavioral brain state, yet this relationship has been largely ignored when studying activity dynamics before spontaneous seizures in medial temporal lobe epilepsy. In light of the increased attention on using single

  7. Spatial Assimilation in Denmark?

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2010-01-01

    . In traditional research literature about immigration it has been shown that for many immigrants living in enclaves has been a temporary situation. The 'spatial assimilation theory' says that this situation ends when the family has become more integrated in the new society and then moves to other parts...

  8. Displacement data assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, W. Steven [Pacific Northwest Laboratory, Richland, WA 99354 (United States); Venkataramani, Shankar [Department of Mathematics and Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721 (United States); Mariano, Arthur J. [Rosenstiel School of Marine & Atmospheric Science, University of Miami, Miami, FL 33149 (United States); Restrepo, Juan M., E-mail: restrepo@math.oregonstate.edu [Department of Mathematics, Oregon State University, Corvallis, OR 97331 (United States)

    2017-02-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information is important. While the displacement transformation is generic, here we implement it within an ensemble Kalman Filter framework and demonstrate its effectiveness in tracking stochastically perturbed vortices.

  9. Epileptic seizures in anaplastic gangliogliomas.

    Science.gov (United States)

    Zanello, Marc; Pagès, Mélanie; Roux, Alexandre; Peeters, Sophie; Dezamis, Edouard; Puget, Stéphanie; Devaux, Bertrand; Sainte-Rose, Christian; Zerah, Michel; Louvel, Guillaume; Dumont, Sarah N; Meder, Jean-François; Grill, Jacques; Huberfeld, Gilles; Chrétien, Fabrice; Parraga, Eduardo; Sauvageon, Xavier; Varlet, Pascale; Pallud, Johan

    2017-04-01

    Prevalence and predictors of epileptic seizures are unknown in the malignant variant of ganglioglioma. In a retrospective exploratory dataset of 18 supratentorial anaplastic World Health Organization grade III gangliogliomas, we studied: (i) the prevalence and predictors of epileptic seizures at diagnosis; (ii) the evolution of seizures during tumor evolution; (iii) seizure control rates and predictors of epilepsy control after oncological treatments. Epileptic seizures prevalence progresses throughout the natural course of anaplastic gangliogliomas: 44% at imaging discovery, 67% at histopathological diagnosis, 69% following oncological treatment, 86% at tumor progression, and 100% at the end-of-life phase. The medical control of seizures and their refractory status worsened during the tumor's natural course: 25% of uncontrolled seizures at histopathological diagnosis, 40% following oncological treatment, 45.5% at tumor progression, and 45.5% at the end-of-life phase. Predictors of seizures at diagnosis appeared related to the tumor location (i.e. temporal and/or cortical involvement). Prognostic parameters of seizure control after first-line oncological treatment were temporal tumor location, eosinophilic granular bodies, TP53 mutation, and extent of resection. Prognostic parameters of seizure control at tumor progression were a history of epileptic seizures at diagnosis, seizure control after first-line oncological treatment, eosinophilic granular bodies, and TP53 mutation. Epileptic seizures are frequently observed in anaplastic gangliogliomas and both prevalence and medically refractory status worsen during the tumor's natural course. Both oncological and antiepileptic treatments should be employed to improve the control of epileptic seizures and the quality of life of patients harboring an anaplastic ganglioglioma.

  10. Contribution of Bicarbonate Assimilation to Carbon Pool Dynamics in the Deep Mediterranean Sea and Cultivation of Actively Nitrifying and CO2-Fixing Bathypelagic Prokaryotic Consortia

    Science.gov (United States)

    La Cono, Violetta; Ruggeri, Gioachino; Azzaro, Maurizio; Crisafi, Francesca; Decembrini, Franco; Denaro, Renata; La Spada, Gina; Maimone, Giovanna; Monticelli, Luis S.; Smedile, Francesco; Giuliano, Laura; Yakimov, Michail M.

    2018-01-01

    Covering two-thirds of our planet, the global deep ocean plays a central role in supporting life on Earth. Among other processes, this biggest ecosystem buffers the rise of atmospheric CO2. Despite carbon sequestration in the deep ocean has been known for a long time, microbial activity in the meso- and bathypelagic realm via the “assimilation of bicarbonate in the dark” (ABD) has only recently been described in more details. Based on recent findings, this process seems primarily the result of chemosynthetic and anaplerotic reactions driven by different groups of deep-sea prokaryoplankton. We quantified bicarbonate assimilation in relation to total prokaryotic abundance, prokaryotic heterotrophic production and respiration in the meso- and bathypelagic Mediterranean Sea. The measured ABD values, ranging from 133 to 370 μg C m−3 d−1, were among the highest ones reported worldwide for similar depths, likely due to the elevated temperature of the deep Mediterranean Sea (13–14°C also at abyssal depths). Integrated over the dark water column (≥200 m depth), bicarbonate assimilation in the deep-sea ranged from 396 to 873 mg C m−2 d−1. This quantity of produced de novo organic carbon amounts to about 85–424% of the phytoplankton primary production and covers up to 62% of deep-sea prokaryotic total carbon demand. Hence, the ABD process in the meso- and bathypelagic Mediterranean Sea might substantially contribute to the inorganic and organic pool and significantly sustain the deep-sea microbial food web. To elucidate the ABD key-players, we established three actively nitrifying and CO2-fixing prokaryotic enrichments. Consortia were characterized by the co-occurrence of chemolithoautotrophic Thaumarchaeota and chemoheterotrophic proteobacteria. One of the enrichments, originated from Ionian bathypelagic waters (3,000 m depth) and supplemented with low concentrations of ammonia, was dominated by the Thaumarchaeota “low-ammonia-concentration” deep

  11. A primer for data assimilation with ecological models using Markov Chain Monte Carlo (MCMC).

    Science.gov (United States)

    Zobitz, J M; Desai, A R; Moore, D J P; Chadwick, M A

    2011-11-01

    Data assimilation, or the fusion of a mathematical model with ecological data, is rapidly expanding knowledge of ecological systems across multiple spatial and temporal scales. As the amount of ecological data available to a broader audience increases, quantitative proficiency with data assimilation tools and techniques will be an essential skill for ecological analysis in this data-rich era. We provide a data assimilation primer for the novice user by (1) reviewing data assimilation terminology and methodology, (2) showcasing a variety of data assimilation studies across the ecological, environmental, and atmospheric sciences with the aim of gaining an understanding of potential applications of data assimilation, and (3) applying data assimilation in specific ecological examples to determine the components of net ecosystem carbon uptake in a forest and also the population dynamics of the mayfly (Hexagenia limbata, Serville). The review and examples are then used to provide guiding principles to newly proficient data assimilation practitioners.

  12. Variational Data Assimilation for the Global Ocean

    Science.gov (United States)

    2013-01-01

    profiles. One method is the Modular Ocean Data Assimilation System ( MODAS ) database, which models the time averaged co-variability of dynamic height...used in the MODAS method is derived from historical hydrographic data. Note that an upgrade to the MODAS synthetic profile capability, the Improved...ans real data constraints. MODAS does not suffer from these limitations, although MODAS may have marginal skill due to: (1) sampling limitations of

  13. Reconstructing mantle heterogeneity with data assimilation based on the back-and-forth nudging method: Implications for mantle-dynamic fitting of past plate motions

    Science.gov (United States)

    Glišović, Petar; Forte, Alessandro

    2016-04-01

    The paleo-distribution of density variations throughout the mantle is unknown. To address this question, we reconstruct 3-D mantle structure over the Cenozoic era using a data assimilation method that implements a new back-and-forth nudging algorithm. For this purpose, we employ convection models for a compressible and self-gravitating mantle that employ 3-D mantle structure derived from joint seismic-geodynamic tomography as a starting condition. These convection models are then integrated backwards in time and are required to match geologic estimates of past plate motions derived from marine magnetic data. Our implementation of the nudging algorithm limits the difference between a reconstruction (backward-in-time solution) and a prediction (forward-in-time solution) on over a sequence of 5-million-year time windows that span the Cenozoic. We find that forward integration of reconstructed mantle heterogeneity that is constrained to match past plate motions delivers relatively poor fits to the seismic-tomographic inference of present-day mantle heterogeneity in the upper mantle. We suggest that uncertainties in the past plate motions, related for example to plate reorganization episodes, could partly contribute to the poor match between predicted and observed present-day heterogeneity. We propose that convection models that allow tectonic plates to evolve freely in accord with the buoyancy forces and rheological structure in the mantle could provide additional constraints on geologic estimates of paleo-configurations of the major tectonic plates.

  14. Dynamical Downscaling of Climate Change Impacts on Wind Energy Resources in the Contiguous United States by Using a Limited-Area Model with Scale-Selective Data Assimilation

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2014-01-01

    Full Text Available By using a limited-area model (LAM in combination with the scale-selective data assimilation (SSDA approach, wind energy resources in the contiguous United States (CONUS were downscaled from IPCC CCSM3 global model projections for both current and future climate conditions. An assessment of climate change impacts on wind energy resources in the CONUS region was then conducted. Based on the downscaling results, when projecting into future climate under IPCC’s A1B scenario, the average annual wind speed experiences an overall shift across the CONUS region. From the current climate to the 2040s, the average annual wind speed is expected to increase from 0.1 to 0.2 m s−1 over the Great Plains, Northern Great Lakes Region, and Southwestern United States located southwest of the Rocky Mountains. When projecting into the 2090s from current climate, there is an overall increase in the Great Plains Region and Southwestern United States located southwest of the Rockies with a mean wind speed increase between 0 and 0.1 m s−1, while, the Northern Great Lakes Region experiences an even greater increase from current climate to 2090s than over the first few decades with an increase of mean wind speed from 0.1 to 0.4 m s−1.

  15. Ensemble data assimilation in the Whole Atmosphere Community Climate Model

    Science.gov (United States)

    Pedatella, N. M.; Raeder, K.; Anderson, J. L.; Liu, H.-L.

    2014-08-01

    We present results pertaining to the assimilation of real lower, middle, and upper atmosphere observations in the Whole Atmosphere Community Climate Model (WACCM) using the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. The ability to assimilate lower atmosphere observations of aircraft and radiosonde temperature and winds, satellite drift winds, and Constellation Observing System for Meteorology, Ionosphere, and Climate refractivity along with middle/upper atmosphere temperature observations from SABER and Aura MLS is demonstrated. The WACCM+DART data assimilation system is shown to be able to reproduce the salient features, and variability, of the troposphere present in the National Centers for Environmental Prediction/National Center for Atmospheric Research Re-Analysis. In the mesosphere, the fit of WACCM+DART to observations is found to be slightly worse when only lower atmosphere observations are assimilated compared to a control experiment that is reflective of the model climatological variability. This differs from previous results which found that assimilation of lower atmosphere observations improves the fit to mesospheric observations. This discrepancy is attributed to the fact that due to the gravity wave drag parameterizations, the model climatology differs significantly from the observations in the mesosphere, and this is not corrected by the assimilation of lower atmosphere observations. The fit of WACCM+DART to mesospheric observations is, however, significantly improved compared to the control experiment when middle/upper atmosphere observations are assimilated. We find that assimilating SABER observations reduces the root-mean-square error and bias of WACCM+DART relative to the independent Aura MLS observations by ˜50%, demonstrating that assimilation of middle/upper atmosphere observations is essential for accurate specification of the mesosphere and lower thermosphere region in WACCM+DART. Last, we demonstrate that

  16. Topographic movie of intracranial ictal high-frequency oscillations with seizure semiology: epileptic network in Jacksonian seizures.

    Science.gov (United States)

    Akiyama, Tomoyuki; Chan, Derrick W; Go, Cristina Y; Ochi, Ayako; Elliott, Irene M; Donner, Elizabeth J; Weiss, Shelly K; Snead, O Carter; Rutka, James T; Drake, James M; Otsubo, Hiroshi

    2011-01-01

    We developed a technique to produce images of dynamic changes in ictal high-frequency oscillations (HFOs) >40 Hz recorded on subdural electroencephalography (EEG) that are time-locked to the ictal EEG and ictal semiology video. We applied this technique to Jacksonian seizures to demonstrate ictal HFO propagation along the homunculus in the primary sensory-motor cortex to visualize the underlying epileptic network. We analyzed intracranial ictal EEGs from two patients with intractable Jacksonian seizures who underwent epilepsy surgery. We calculated the degrees of increase in amplitude within 40-80, 80-200, and 200-300 Hz frequency bands compared to the interictal period and converted them into topographic movies projected onto the brain surface picture. We combined these data with the ictal EEGs and video of the patient demonstrating ictal semiology. The ictal HFOs began in the sensory cortex and appeared concomitantly with the sensory aura. They then propagated to the motor cortex at the same time that focal motor symptoms evolved. As the seizure progressed, the ictal HFOs spread or reverberated in the rolandic region. However, even when the seizure became secondarily generalized, the ictal HFOs were confined to the rolandic region. In both cases, there was increased amplitude of higher frequency bands during seizure initiation compared to seizure progression. This combined movie showed the ictal HFO propagation corresponding to the ictal semiology in Jacksonian seizures and revealed the epileptic network involved in seizure initiation and progression. This method may advance understanding of neural network activities relating to clinical seizure generation and propagation. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

  17. Detection and Prediction of Epileptic Seizures

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas

    monitoring of their brain waves. More specifically, three issues were investigated: The feasibility of automatic seizure prediction, optimization of automatic seizure detection algorithms, and the link between intra- and extracranial EEG. Regarding feasibility of automatic seizure prediction, neither...

  18. Delay Differential Analysis of Seizures in Multichannel Electrocorticography Data.

    Science.gov (United States)

    Lainscsek, Claudia; Weyhenmeyer, Jonathan; Cash, Sydney S; Sejnowski, Terrence J

    2017-12-01

    High-density electrocorticogram (ECoG) electrodes are capable of recording neurophysiological data with high temporal resolution with wide spatial coverage. These recordings are a window to understanding how the human brain processes information and subsequently behaves in healthy and pathologic states. Here, we describe and implement delay differential analysis (DDA) for the characterization of ECoG data obtained from human patients with intractable epilepsy. DDA is a time-domain analysis framework based on embedding theory in nonlinear dynamics that reveals the nonlinear invariant properties of an unknown dynamical system. The DDA embedding serves as a low-dimensional nonlinear dynamical basis onto which the data are mapped. This greatly reduces the risk of overfitting and improves the method's ability to fit classes of data. Since the basis is built on the dynamical structure of the data, preprocessing of the data (e.g., filtering) is not necessary. We performed a large-scale search for a DDA model that best fit ECoG recordings using a genetic algorithm to qualitatively discriminate between different cortical states and epileptic events for a set of 13 patients. A single DDA model with only three polynomial terms was identified. Singular value decomposition across the feature space of the model revealed both global and local dynamics that could differentiate electrographic and electroclinical seizures and provided insights into highly localized seizure onsets and diffuse seizure terminations. Other common ECoG features such as interictal periods, artifacts, and exogenous stimuli were also analyzed with DDA. This novel framework for signal processing of seizure information demonstrates an ability to reveal unique characteristics of the underlying dynamics of the seizure and may be useful in better understanding, detecting, and maybe even predicting seizures.

  19. Alcohol withdrawal seizures.

    Science.gov (United States)

    Hughes, John R

    2009-06-01

    The topic of alcohol withdrawal syndrome (AWS), including delirium tremens and especially seizures, is reviewed. From mice and rat studies, it is known that both N-methyl-d-aspartate (NMDA) and gamma-aminobutyric acid (GABA) receptors are involved in AWS. During alcohol intoxication chronic adaptations of NMDA and GABA receptors occur, and during alcohol withdrawal a hyperexcitable state develops. In studies on humans, during intoxication the NMDA receptors are activated and mediate tonic inhibition. In withdrawal, a rebound activation of these receptors occurs. Both GABA-A and GABA-B receptors, especially the alpha2 subunit of GABA-A receptors, are also likely involved. Homocysteine increases with active drinking, and in withdrawal, excitotoxicity likely is induced by a further increase in homocysteine, viewed as a risk factor for AWS and also as a screening tool. The dopamine transporter gene is also associated with AWS. Characteristics involves changes in the ECG, especially an increase in QT interval, and EEG changes, including abnormal quantified EEG, at times periodic lateralized epileptiform discharges, and especially seizures, usually occurring 6-48h after the cessation of drinking. Therapy has emphasized benzodiazepines, mainly diazepam and lorazepam, but more standard antiepileptic drugs, like carbamazepine and topiramate, are also effective and safe.

  20. MMR Vaccination and Febrile Seizures

    DEFF Research Database (Denmark)

    Vestergaard, Mogens; Hviid, Anders; Madsen, Kreesten Meldgaard

    2004-01-01

    CONTEXT: The rate of febrile seizures increases following measles, mumps, and rubella (MMR) vaccination but it is unknown whether the rate varies according to personal or family history of seizures, perinatal factors, or socioeconomic status. Furthermore, little is known about the long-term outco...

  1. Fluoxetine Overdose-Induced Seizure

    OpenAIRE

    Suchard, Jeffrey R.

    2008-01-01

    A 37-year-old woman experienced a witnessed generalized seizure in the Emergency Department three hours after ingesting approximately 1400 mg of fluoxetine in a suicide attempt. Although the majority of fluoxetine ingestions are benign, seizures may occur after large intentional overdoses. [WestJEM. 2008;9:154-156

  2. Localization of pediatric seizure semiology.

    Science.gov (United States)

    Vendrame, Martina; Zarowski, Marcin; Alexopoulos, Andreas V; Wyllie, Elaine; Kothare, Sanjeev V; Loddenkemper, Tobias

    2011-10-01

    The aim of this study was to evaluate the relationship between semiology of seizures in children and adolescents to the corresponding EEG localization. Charts of 225 consecutive pediatric epilepsy patients undergoing Video-EEG monitoring (VEM) over 2 years were reviewed. Seizure semiology recorded during VEM was classified according to ILAE seizure semiology terminology and EEG localization, and analyzed based on onset as defined by the EEG data (generalized, frontal, temporal, parietal, occipital or multilobar). A total of 1008 seizures were analyzed in 225 children (mean age 8.5 years, range 0-20), with 50% boys. Auras and seizures with automatisms arose predominantly from the temporal lobes (psemiologies relate to specific brain regions, with overlap between focal and generalized semiological seizure types, as identified electrographically. Semiology of seizures can provide important information for epilepsy localization, and should not be overlooked, especially in patients undergoing pre-surgical evaluation. Separation of clinical seizure description and EEG findings may be useful, in particular when only incomplete information is available. i.e. during the first office visit. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Regional Ocean Data Assimilation

    KAUST Repository

    Edwards, Christopher A.

    2015-01-03

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  4. Cultural Assimilation versus Cultural Pluralism.

    Science.gov (United States)

    Mohl, Raymond A.

    1981-01-01

    Examines the historical role of American schools as instruments of Americanization and assimilation processes. Traces the origins of cultural pluralism and discusses its implications for minority education. (SK)

  5. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) is a middleware architecture that facilitates the incorporation of heterogeneous sensing and control devices...

  6. Integrated Data Assimilation Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Data Assimilation Architecture (IDAA) addresses the fundamental problem of command, control, and communications systems interoperability....

  7. [Reflex seizures, cinema and television].

    Science.gov (United States)

    Olivares-Romero, Jesús

    2015-12-16

    In movies and television series are few references to seizures or reflex epilepsy even though in real life are an important subgroup of total epileptic syndromes. It has performed a search on the topic, identified 25 films in which they appear reflex seizures. Most seizures observed are tonic-clonic and visual stimuli are the most numerous, corresponding all with flashing lights. The emotions are the main stimuli in higher level processes. In most cases it is not possible to know if a character suffers a reflex epilepsy or suffer reflex seizures in the context of another epileptic syndrome. The main conclusion is that, in the movies, the reflex seizures are merely a visual reinforcing and anecdotal element without significant influence on the plot.

  8. Audiogenic reflex seizures in cats

    Science.gov (United States)

    Lowrie, Mark; Bessant, Claire; Harvey, Robert J; Sparkes, Andrew; Garosi, Laurent

    2015-01-01

    Objectives This study aimed to characterise feline audiogenic reflex seizures (FARS). Methods An online questionnaire was developed to capture information from owners with cats suffering from FARS. This was collated with the medical records from the primary veterinarian. Ninety-six cats were included. Results Myoclonic seizures were one of the cardinal signs of this syndrome (90/96), frequently occurring prior to generalised tonic–clonic seizures (GTCSs) in this population. Other features include a late onset (median 15 years) and absence seizures (6/96), with most seizures triggered by high-frequency sounds amid occasional spontaneous seizures (up to 20%). Half the population (48/96) had hearing impairment or were deaf. One-third of cats (35/96) had concurrent diseases, most likely reflecting the age distribution. Birmans were strongly represented (30/96). Levetiracetam gave good seizure control. The course of the epilepsy was non-progressive in the majority (68/96), with an improvement over time in some (23/96). Only 33/96 and 11/90 owners, respectively, felt the GTCSs and myoclonic seizures affected their cat’s quality of life (QoL). Despite this, many owners (50/96) reported a slow decline in their cat’s health, becoming less responsive (43/50), not jumping (41/50), becoming uncoordinated or weak in the pelvic limbs (24/50) and exhibiting dramatic weight loss (39/50). These signs were exclusively reported in cats experiencing seizures for >2 years, with 42/50 owners stating these signs affected their cat’s QoL. Conclusions and relevance In gathering data on audiogenic seizures in cats, we have identified a new epilepsy syndrome named FARS with a geriatric onset. Further studies are warranted to investigate potential genetic predispositions to this condition. PMID:25916687

  9. Predicting epileptic seizures in advance.

    Directory of Open Access Journals (Sweden)

    Negin Moghim

    Full Text Available Epilepsy is the second most common neurological disorder, affecting 0.6-0.8% of the world's population. In this neurological disorder, abnormal activity of the brain causes seizures, the nature of which tend to be sudden. Antiepileptic Drugs (AEDs are used as long-term therapeutic solutions that control the condition. Of those treated with AEDs, 35% become resistant to medication. The unpredictable nature of seizures poses risks for the individual with epilepsy. It is clearly desirable to find more effective ways of preventing seizures for such patients. The automatic detection of oncoming seizures, before their actual onset, can facilitate timely intervention and hence minimize these risks. In addition, advance prediction of seizures can enrich our understanding of the epileptic brain. In this study, drawing on the body of work behind automatic seizure detection and prediction from digitised Invasive Electroencephalography (EEG data, a prediction algorithm, ASPPR (Advance Seizure Prediction via Pre-ictal Relabeling, is described. ASPPR facilitates the learning of predictive models targeted at recognizing patterns in EEG activity that are in a specific time window in advance of a seizure. It then exploits advanced machine learning coupled with the design and selection of appropriate features from EEG signals. Results, from evaluating ASPPR independently on 21 different patients, suggest that seizures for many patients can be predicted up to 20 minutes in advance of their onset. Compared to benchmark performance represented by a mean S1-Score (harmonic mean of Sensitivity and Specificity of 90.6% for predicting seizure onset between 0 and 5 minutes in advance, ASPPR achieves mean S1-Scores of: 96.30% for prediction between 1 and 6 minutes in advance, 96.13% for prediction between 8 and 13 minutes in advance, 94.5% for prediction between 14 and 19 minutes in advance, and 94.2% for prediction between 20 and 25 minutes in advance.

  10. Treating acute seizures with benzodiazepines: does seizure duration matter?

    Science.gov (United States)

    Naylor, David E

    2014-10-01

    Several clinical trials have shown improved seizure control and outcome by early initiation of treatment with benzodiazepines, before arrival in the emergency department and before intravenous access can be established. Here, evidence is provided and reviewed for rapid treatment of acute seizures in order to avoid the development of benzodiazepine pharmacoresistance and the emergence of self-sustaining status epilepticus. Alterations in the physiology, pharmacology, and postsynaptic level of GABA-A receptors can develop within minutes to an hour and hinder the ability of synaptic inhibition to stop seizures while also impairing the efficacy of GABAergic agents, such as benzodiazepines, to boost impaired inhibition. In addition, heightened excitatory transmission further exacerbates the inhibitory/excitatory balance and makes seizure control even more resistant to treatment. The acute increase in the surface expression of NMDA receptors during prolonged seizures also may cause excitotoxic injury, cell death, and other pathological expressions and re-arrangements of receptor subunits that all contribute to long-term sequelae such as cognitive impairment and chronic epilepsy. In conclusion, a short window of opportunity exists when seizures are maximally controlled by first-line benzodiazepine treatment. After that, multiple pathological mechanisms quickly become engaged that make seizures increasingly more difficult to control with high risk for long-term harm.

  11. Cluster analysis of clinical seizure semiology of psychogenic nonepileptic seizures.

    Science.gov (United States)

    Gröppel, G; Kapitany, T; Baumgartner, C

    2000-05-01

    To develop an objective classification of psychogenic nonepileptic seizures (NES) based on cluster analysis of clinical seizure semiology. We studied the clinical seizure semiology in 27 patients with psychogenic NES documented by prolonged video-EEG monitoring. We analyzed the following clinical symptoms: clonic and hypermotor movements as well as trembling of the upper and/or lower extremities, pelvic thrusting, head movements, tonic posturing backward of the head, and falling. We used cluster analysis to identify symptoms occurring together in a systematic way and thus tried to achieve a clinical classification of psychogenic NES. We could identify three symptom clusters. Cluster 1 was characterized by clonic and hypermotor movements of the extremities, pelvic thrusting, head movements, and tonic posturing of the head, and therefore was named "psychogenic motor seizures." Cluster 2 comprised trembling of the upper and lower extremities and was termed "psychogenic minor motor or trembling seizures." Cluster 3 consisted of falling to the floor as the only symptom and was referred to as "psychogenic atonic seizures." Our study represents the first study to analyze the clinical semiology of psychogenic NES by cluster analysis, which should be useful for an objective classification of psychogenic NES. This classification should allow both a better characterization of psychogenic NES and an easier differential diagnosis against specific epileptic seizures.

  12. Probabilistic forecasting and Bayesian data assimilation

    CERN Document Server

    Reich, Sebastian

    2015-01-01

    In this book the authors describe the principles and methods behind probabilistic forecasting and Bayesian data assimilation. Instead of focusing on particular application areas, the authors adopt a general dynamical systems approach, with a profusion of low-dimensional, discrete-time numerical examples designed to build intuition about the subject. Part I explains the mathematical framework of ensemble-based probabilistic forecasting and uncertainty quantification. Part II is devoted to Bayesian filtering algorithms, from classical data assimilation algorithms such as the Kalman filter, variational techniques, and sequential Monte Carlo methods, through to more recent developments such as the ensemble Kalman filter and ensemble transform filters. The McKean approach to sequential filtering in combination with coupling of measures serves as a unifying mathematical framework throughout Part II. Assuming only some basic familiarity with probability, this book is an ideal introduction for graduate students in ap...

  13. Cannabidiol Rescues Acute Hepatic Toxicity and Seizure Induced by Cocaine

    Science.gov (United States)

    Vilela, Luciano Rezende; Gomides, Lindisley Ferreira; David, Bruna Araújo; Antunes, Maísa Mota; Diniz, Ariane Barros; Moreira, Fabrício de Araújo; Menezes, Gustavo Batista

    2015-01-01

    Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD), protects against cocaine toxicity. URB597 (1.0 mg/kg) abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg) reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen) increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse. PMID:25999668

  14. Cannabidiol Rescues Acute Hepatic Toxicity and Seizure Induced by Cocaine

    Directory of Open Access Journals (Sweden)

    Luciano Rezende Vilela

    2015-01-01

    Full Text Available Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD, protects against cocaine toxicity. URB597 (1.0 mg/kg abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse.

  15. Early seizure detection in an animal model of temporal lobe epilepsy

    Science.gov (United States)

    Talathi, Sachin S.; Hwang, Dong-Uk; Ditto, William; Carney, Paul R.

    2007-11-01

    The performance of five seizure detection schemes, i.e., Nonlinear embedding delay, Hurst scaling, Wavelet Scale, autocorrelation and gradient of accumulated energy, in their ability to detect EEG seizures close to the seizure onset time were evaluated to determine the feasibility of their application in the development of a real time closed loop seizure intervention program (RCLSIP). The criteria chosen for the performance evaluation were, high statistical robustness as determined through the predictability index, the sensitivity and the specificity of a given measure to detect an EEG seizure, the lag in seizure detection with respect to the EEG seizure onset time, as determined through visual inspection and the computational efficiency for each detection measure. An optimality function was designed to evaluate the overall performance of each measure dependent on the criteria chosen. While each of the above measures analyzed for seizure detection performed very well in terms of the statistical parameters, the nonlinear embedding delay measure was found to have the highest optimality index due to its ability to detect seizure very close to the EEG seizure onset time, thereby making it the most suitable dynamical measure in the development of RCLSIP in rat model with chronic limbic epilepsy.

  16. Cross-scale effects of neural interactions during human neocortical seizure activity

    NARCIS (Netherlands)

    Eissa, Tahra L.; Dijkstra, Koen; Brune, Christoph; Emerson, Ronald G.; Van Putten, Michel J. A. M.; Goodman, Robert R.; McKhann Jr., Guy M.; Schevon, Catherine A.; van Drongelen, Wim; van Gils, Stephan A.

    2017-01-01

    Small-scale neuronal networks may impose widespread effects on large network dynamics. To unravel this relationship, we analyzed eight multiscale recordings of spontaneous seizures from four patients with epilepsy. During seizures, multiunit spike activity organizes into a submillimeter-sized

  17. Recent Advances in Neonatal Seizures.

    Science.gov (United States)

    Sands, Tristan T; McDonough, Tiffani L

    2016-10-01

    This article strives to review and summarize selected recent literature and topics contributing to a greater understanding of the diagnosis and treatments of neonatal seizures that have emerged in the past several years. Continuous EEG is recommended as the gold standard for neonatal seizure monitoring as it can provide additional information that may stratify patients by etiology, as well as identify at-risk groups of newborns for neuromonitoring. Investigations are moving beyond traditional antiepileptic agents in search of treatments with better efficacy and with less concern for developmental effects. Targeted therapies for seizures resulting from particular genetic conditions are increasing, highlighting the importance of early genetic diagnosis. Better understanding of the risk of post-neonatal epilepsy based on etiology is emerging with new epidemiological studies. Evidence is growing for deleterious effects of seizures on outcomes, elevating the importance of seizure detection and effective treatment. Advances in utilization of continuous EEG monitoring have improved the accuracy of seizure detection and have identified at-risk groups of newborns for neuromonitoring. Ultimately, the goal in management of neonatal seizures is not only clinical stabilization in the acute period but also to influence neurodevelopmental outcome and modify the risk of future epilepsy.

  18. Semiology of hypermotor (hyperkinetic) seizures.

    Science.gov (United States)

    Alqadi, Khalid; Sankaraneni, Ram; Thome, Ursula; Kotagal, Prakash

    2016-01-01

    Hypermotor seizures (HMSs) consist of complex movements involving proximal segments of the limbs and trunk that appear violent and inappropriate for the situation. We analyzed hypermotor seizure videos in seizure-free patients (Engel class I) following resective epilepsy surgery. After completion of video analysis, we reviewed EEG and neuroimaging data. Search of our epilepsy surgery database yielded 116 patients classified as having hypermotor seizures between 1996 and 2013. From this subset, 17/31 (55%) patients had been seizure-free for >6months (mean follow-up: 3.3years). Mean seizure duration was 35s (range: 6-91s), of which the HM phase lasted a mean of 22s (range: 3-53s). In 16 patients (95%), hypermotor activity was seen at or within 10s of clinical seizure onset. Type I semiology occurred in 6 patients, type II semiology in 10 patients, and 1 patient exhibited features of both. Type I and type II semiologies were noted in patients who had frontal lobe as well as extrafrontal resections. Nonversive head and body turning occurred in 10 patients (ranging from 90° to 270°) which was ipsilateral to the side of resection in all patients and seen both in frontal and extrafrontal resections. Six out of eleven patients with abnormal MRI and 4/6 patients with nonlesional MRI underwent invasive EEG evaluation. Eight patients (47%) had frontal lobe resection, 4/17 (23%) patients had temporal lobe resection, and one patient each had parietal lobe, insular, temporoparietooccipital, or motor sparing resection; 1 patient had functional hemispherectomy. Hypermotor semiology typically occurs at or within 10s after seizure onset. Ipsilateral head/body turning appears to be of lateralizing value whereas asymmetry of limb movement was not lateralizing. Hypermotor semiology is most often seen in frontal lobe epilepsy but may occur in seizures arising from other locations. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Predicting epileptic seizures from scalp EEG based on attractor state analysis.

    Science.gov (United States)

    Chu, Hyunho; Chung, Chun Kee; Jeong, Woorim; Cho, Kwang-Hyun

    2017-05-01

    -based analysis of the macroscopic dynamics of the brain. With the scalp EEG, we first propose use of a spectral feature identified for seizure prediction, in which the dynamics of an attractor are excluded, and only the perturbation dynamics from the attractor are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Nonlinear data assimilation

    CERN Document Server

    Van Leeuwen, Peter Jan; Reich, Sebastian

    2015-01-01

    This book contains two review articles on nonlinear data assimilation that deal with closely related topics but were written and can be read independently. Both contributions focus on so-called particle filters. The first contribution by Jan van Leeuwen focuses on the potential of proposal densities. It discusses the issues with present-day particle filters and explorers new ideas for proposal densities to solve them, converging to particle filters that work well in systems of any dimension, closing the contribution with a high-dimensional example. The second contribution by Cheng and Reich discusses a unified framework for ensemble-transform particle filters. This allows one to bridge successful ensemble Kalman filters with fully nonlinear particle filters, and allows a proper introduction of localization in particle filters, which has been lacking up to now.

  1. Sea level ECV quality assessment via global ocean model assimilation

    Science.gov (United States)

    Scharffenberg, Martin; Köhl, Armin; Stammer, Detlef

    2015-04-01

    In the ocean modeling community satellite data, especially SSH fields, are assimilated on a regular basis. SSH fields are very important in this context because of their dynamical relevance for constraining the ocean's flow field. However, assimilating SSH data into an ocean model does not only improve the quality of model but in addition, can also help testing the quality and the consistency of the input data as well. In our work we aim to quantify improvements in Sea Level (SL) data through the ESA - Climate Change Initiative (cci) effort and we aim to test the consistency of the Essential Climate Variable (ECV) of Sea Level (SL_ECV) with other ECVs through the assimilation process and to investigate where remaining inconsistencies exist and why. For this purpose the GECCO2 assimilation approach assimilates SSH jointly with in situ data over the ocean. The dynamically consistent ocean state estimation adjusts only uncertain model parameters to bring the model into consistency with ocean observations. Improvements in data products can be investigated by studying the residuals between the different data products and the constrained model. PHASE 1: With this approach we could demonstrate, that in many regions the SL_ECV has been improved from version V0 (AVISO product) to version V1 (SL_cci product). However, there are regions where SL_ECV_V1 is further away from the model "truth". In that sense it is important to understand that the model assimilated SL_ECV_V0 (origianl AVISO product) and therefore has tried to adapt to the SL_ECV_V0. Therefore, inconsistencies existed when comparing the synthesis results to the updated version SL_ECV_V1! These deviations between the model "truth" and the improved data product (SL_ECV_V1) increased mostly in low energetic areas. PHASE 2: Two GECCO2-assimilation-runs (5 additional iterations) have been performed to date: 1) assimilating the original AVISO SL-product (V0) and 2) assimilating the updated-improved sea level estimate

  2. Predicting seizure by modeling synaptic plasticity based on EEG signals - a case study of inherited epilepsy.

    Science.gov (United States)

    Zhang, Honghui; Su, Jianzhong; Wang, Qingyun; Liu, Yueming; Good, Levi; Pascual, Juan

    2018-03-01

    This paper explores the internal dynamical mechanisms of epileptic seizures through quantitative modeling based on full brain electroencephalogram (EEG) signals. Our goal is to provide seizure prediction and facilitate treatment for epileptic patients. Motivated by an earlier mathematical model with incorporated synaptic plasticity, we studied the nonlinear dynamics of inherited seizures through a differential equation model. First, driven by a set of clinical inherited electroencephalogram data recorded from a patient with diagnosed Glucose Transporter Deficiency, we developed a dynamic seizure model on a system of ordinary differential equations. The model was reduced in complexity after considering and removing redundancy of each EEG channel. Then we verified that the proposed model produces qualitatively relevant behavior which matches the basic experimental observations of inherited seizure, including synchronization index and frequency. Meanwhile, the rationality of the connectivity structure hypothesis in the modeling process was verified. Further, through varying the threshold condition and excitation strength of synaptic plasticity, we elucidated the effect of synaptic plasticity to our seizure model. Results suggest that synaptic plasticity has great effect on the duration of seizure activities, which support the plausibility of therapeutic interventions for seizure control.

  3. Management of Reflex Anoxic Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-10-01

    Full Text Available Investigators at the Roald Dahl EEG Unit, Alder Hey Children’s NHS Foundation, Liverpool, UK, review the definition, pathophysiology, clinical presentation, and management of reflex anoxic seizures (RAS in children.

  4. Dissociation of spontaneous seizures and brainstem seizure thresholds in mice exposed to eight flurothyl-induced generalized seizures.

    Science.gov (United States)

    Kadiyala, Sridhar B; Ferland, Russell J

    2017-03-01

    C57BL/6J mice exposed to eight flurothyl-induced generalized clonic seizures exhibit a change in seizure phenotype following a 28-day incubation period and subsequent flurothyl rechallenge. Mice now develop a complex seizure semiology originating in the forebrain and propagating into the brainstem seizure network (a forebrain→brainstem seizure). In contrast, this phenotype change does not occur in seizure-sensitive DBA/2J mice. The underlying mechanism(s) was the focus of these studies. DBA2/J mice were exposed to eight flurothyl-induced seizures (1/day) followed by 24-hour video-electroencephalographic recordings for 28-days. Forebrain and brainstem seizure thresholds were determined in C57BL/6J and DBA/2J mice following one or eight flurothyl-induced seizures, or after eight flurothyl-induced seizures, a 28-day incubation period, and final flurothyl rechallenge. Similar to C57BL/6J mice, DBA2/J mice expressed spontaneous seizures. However, unlike C57BL/6J mice, DBA2/J mice continued to have spontaneous seizures without remission. Because DBA2/J mice do not express forebrain→brainstem seizures following flurothyl rechallenge after a 28-day incubation period, this indicated that spontaneous seizures were not sufficient for the evolution of forebrain→brainstem seizures. Therefore, we determined whether brainstem seizure thresholds were changing during this repeated-flurothyl model and whether this could account for the expression of forebrain→brainstem seizures. Brainstem seizure thresholds were not different between C57BL/6J and DBA/2J mice on day one or on the last induction seizure trial (day eight). However, brainstem seizure thresholds did differ significantly on flurothyl rechallenge (day 28) with DBA/2J mice showing no lowering of their brainstem seizure thresholds. These results demonstrated that DBA/2J mice exposed to the repeated-flurothyl model develop spontaneous seizures without evidence of seizure remission and provide a new model of

  5. Toward data-driven methods in geophysics: the Analog Data Assimilation

    Science.gov (United States)

    Lguensat, Redouane; Tandeo, Pierre; Ailliot, Pierre; Pulido, Manuel; Fablet, Ronan

    2017-04-01

    The Analog Data Assimilation (AnDA) is a recently introduced data-driven methods for data assimilation where the dynamical model is learned from data, contrary to classical data assimilation where a physical model of the dynamics is needed. AnDA relies on replacing the physical dynamical model by a statistical emulator of the dynamics using analog forecasting methods. Then, the analog dynamical model is incorporated in ensemble-based data assimilation algorithms (Ensemble Kalman Filter and Smoother or Particle Filter). The relevance of the proposed AnDA is demonstrated for Lorenz-63 and Lorenz-96 chaotic dynamics. Applications in meteorology and oceanography as well as potential perspectives that are worthy of investigation are further discussed. We expect that the directions of research we suggest will help in bringing more interest in applied machine learning to geophysical sciences.

  6. Management Of Post Stroke Seizures

    Directory of Open Access Journals (Sweden)

    Kavian Ghandehari

    2017-02-01

    Full Text Available The incidence of seizures in relation to stroke is 8.9%, with a frequency of 10.6 and 8.6% in haemorrhagic and ischaemic stroke, respectively. In subarachnoid haemorrhage the incidence is 8.5%. Due to the fact that infarcts are significantly more frequent than haemorrhages, seizures are mainly related to occlusive vascular disease of the brain. The general view is to consider stroke-related seizures as harmless complications in the course of a prolonged vascular disease involving the heart and brain. Seizures can be classified as those of early and those of late onset in a paradigm comparable to post-traumatic epilepsy, with an arbitrary dividing point of two weeks after the event. Most early-onset seizures occur during the first day after the stroke. Late-onset seizures occur three times more often than early-onset ones. A first late-onset epileptic event is most likely to take place between six months and two years after the stroke. However, up to 28% of patients develop their first seizure several years later. Simple partial seizures, with or without secondary generalisation, account for about 50% of total seizures, while complex partial spells, with or without secondary generalisation, and primary generalised tonic–clonic insults account for approximately 25% each. Status epilepticus occurs in 12% of stroke patients, but the recurrence rate after an initial status epilepticus is not higher than after a single seizure. Inhibitory seizures, mimicking transient ischaemic attacks, are observed in 7.1% of cases. The only clinical predictor of late-onset seizures is the initial presentation of partial anterior circulation syndrome due to a territorial infarct. Patients with total anterior circulation syndrome have less chance of developing epileptic spells, not only due to their shorter life expectancy but also due to the fact that the large infarcts are sharply demarcated in these patients. The optimal timing and type of antiepileptic drug

  7. Aerosol Data Assimilation at GMAO

    Science.gov (United States)

    da Silva, Arlindo M.; Buchard, Virginie

    2017-01-01

    This presentation presents an overview of the aerosol data assimilation work performed at GMAO. The GMAO Forward Processing system and the biomass burning emissions from QFED are first presented. Then, the current assimilation of Aerosol Optical Depth (AOD), performed by means of the analysis splitting method is briefly described, followed by some results on the quality control of observations using a Neural Network trained using AERONET AOD. Some applications are shown such as the Mount Pinatubo eruption in 1991 using the MERRA-2 aerosol dataset. Finally preliminary results on the EnKF implementation for aerosol assimilation are presented.

  8. Automated seizure detection systems and their effectiveness for each type of seizure

    National Research Council Canada - National Science Library

    Ulate-Campos, A; Coughlin, F; Gaínza-Lein, M; Fernández, I Sánchez; Pearl, P L; Loddenkemper, T

    2016-01-01

    ...% of patients with refractory epilepsy have one or more seizures per month. Seizure detection devices allow an objective assessment of seizure frequency and a treatment tailored to the individual patient...

  9. A novel genetic programming approach for epileptic seizure detection.

    Science.gov (United States)

    Bhardwaj, Arpit; Tiwari, Aruna; Krishna, Ramesh; Varma, Vishaal

    2016-02-01

    The human brain is a delicate mix of neurons (brain cells), electrical impulses and chemicals, known as neurotransmitters. Any damage has the potential to disrupt the workings of the brain and cause seizures. These epileptic seizures are the manifestations of epilepsy. The electroencephalograph (EEG) signals register average neuronal activity from the cerebral cortex and label changes in activity over large areas. A detailed analysis of these electroencephalograph (EEG) signals provides valuable insights into the mechanisms instigating epileptic disorders. Moreover, the detection of interictal spikes and epileptic seizures in an EEG signal plays an important role in the diagnosis of epilepsy. Automatic seizure detection methods are required, as these epileptic seizures are volatile and unpredictable. This paper deals with an automated detection of epileptic seizures in EEG signals using empirical mode decomposition (EMD) for feature extraction and proposes a novel genetic programming (GP) approach for classifying the EEG signals. Improvements in the standard GP approach are made using a Constructive Genetic Programming (CGP) in which constructive crossover and constructive subtree mutation operators are introduced. A hill climbing search is integrated in crossover and mutation operators to remove the destructive nature of these operators. A new concept of selecting the Globally Prime offspring is also presented to select the best fitness offspring generated during crossover. To decrease the time complexity of GP, a new dynamic fitness value computation (DFVC) is employed to increase the computational speed. We conducted five different sets of experiments to evaluate the performance of the proposed model in the classification of different mixtures of normal, interictal and ictal signals, and the accuracies achieved are outstandingly high. The experimental results are compared with the existing methods on same datasets, and these results affirm the potential use of

  10. Global Land Data Assimilation System

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The goal of the Global Land Data Assimilation System (GLDAS) is to ingest satellite- and ground-based observational data products, using advanced land surface...

  11. Global Data Assimilation System (GDAS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Data Assimilation System (GDAS) is the system used by the Global Forecast System (GFS) model to place observations into a gridded model space for the...

  12. Ethnic Goods and Immigrant Assimilation

    OpenAIRE

    Abdulloev, Ilhom; Gil S. Epstein; Ira N. Gang

    2014-01-01

    Some immigrants try to keep their ethnicity hidden while others become ever deeply more mired in their home culture. We argue that among immigrants this struggle manifests itself in the ethnic goods they choose to consume. Different types of ethnic goods have vastly different effects on immigrant assimilation. We develop a simple theoretical model useful for capturing the consequences of this struggle, illustrating it with examples of Central Asian assimilation into the Muscovite economy.

  13. Intranasal therapies for acute seizures.

    Science.gov (United States)

    Kälviäinen, Reetta

    2015-08-01

    Most seizure emergencies occur outside of the hospital, and there is a need for treatment interventions that can be administered quickly and safely by nonclinical caregivers. Intranasal benzodiazepine administration does not require intravenous access and offers rapid seizure cessation. Intranasal midazolam is faster at aborting seizure activity than rectal diazepam and quicker to administer than intravenous diazepam. Although time to seizure cessation varies from study to study, intranasal midazolam is efficacious when administered not only by emergency department personnel but also by paramedics and caregivers in out-of-hospital and home settings. Absorption of midazolam intranasal formulations appears to be relatively rapid compared to diazepam formulations. Its shorter elimination half-life may also be beneficial in that patients may more quickly return to normal function because of rapid offset of effect. On the other hand, the faster rate of elimination of midazolam may expose patients to a higher rate of seizure recurrence compared with diazepam. Two diazepam formulations and one midazolam formulation are being currently developed for intranasal use. This article is part of a Special Issue entitled "Status Epilepticus". Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Automated seizure detection systems and their effectiveness for each type of seizure.

    Science.gov (United States)

    Ulate-Campos, A; Coughlin, F; Gaínza-Lein, M; Fernández, I Sánchez; Pearl, P L; Loddenkemper, T

    2016-08-01

    Epilepsy affects almost 1% of the population and most of the approximately 20-30% of patients with refractory epilepsy have one or more seizures per month. Seizure detection devices allow an objective assessment of seizure frequency and a treatment tailored to the individual patient. A rapid recognition and treatment of seizures through closed-loop systems could potentially decrease morbidity and mortality in epilepsy. However, no single detection device can detect all seizure types. Therefore, the choice of a seizure detection device should consider the patient-specific seizure semiologies. This review of the literature evaluates seizure detection devices and their effectiveness for different seizure types. Our aim is to summarize current evidence, offer suggestions on how to select the most suitable seizure detection device for each patient and provide guidance to physicians, families and researchers when choosing or designing seizure detection devices. Further, this review will guide future prospective validation studies. Copyright © 2016. Published by Elsevier Ltd.

  15. Semiological seizure classification of epileptic seizures in children admitted to video-EEG monitoring unit.

    Science.gov (United States)

    Alan, Serdar; Yalnızoğlu, Dilek; Turanlı, Güzide; Karlı-Oğuz, Kader; Lay-Ergun, Eser; Söylemezoğlu, Figen; Akalan, Nejat; Topçu, Meral

    2015-01-01

    We aimed to determine seizure characteristics of pediatric patients with epilepsy, and evaluate if Semiological Seizure Classification (SSC) system is applicable in this cohort. We retrospectively studied 183 patients, aged between 3 months-18 years, admitted to the video-EEG monitoring unit (VEMU). Most patients suffered from intractable epilepsy with comorbidities, and had structural lesions. Seizures were classified based on ictal video-EEG recordings by using SSC system; 157 patients had only one seizure type, 26 had more than one seizure types. Overall 211 seizures and 373 semiologies were analyzed; 114 seizures (54%) had more than one semiological subtype. The most frequent semiology was motor seizures (78%), followed by dialeptic seizures (12%). The most common subtypes were simple motor seizures (49%); tonic seizures constituted (28.4%) of all semiologies. We conclude that SSC system is applicable for children with epilepsy admitted to VEMU; complementary EEG and imaging data are required for evaluation of patients with epilepsy.

  16. Varying seizure semiology according to age.

    Science.gov (United States)

    Nordli, Douglas R

    2013-01-01

    The clinical manifestations of seizures change in a predictable fashion with advancing age. For focal seizures these changes can be summarized into domains similar to those used in developmental models. These include fine motor, communication, and gross motor manifestations. Instead of socialization the fourth domain for seizure semiology concerns synchronization. Focal seizures in the very young tend to be simpler with fewer fine motor manifestations. Auras are uncommon, even in young children with some linguistic skill and it is often difficult to discern alteration of consciousness. Infantile focal seizures can present with spasms or even diffuse tonic seizures. In terms of synchronization, orderly secondary generalization is rarely seen so that primary generalized clonic seizures are rarely recorded in infants. Amongst so-called "generalized" seizures spasms are most often seen in the first year of life. Absence seizures, myoclonic-astatic and generalized tonic-clonic seizures are all usually not seen until after age 2 years. A full description of the clinical details of seizures is probably the most important part of the epilepsy history. A detailed knowledge of seizure semiology can make the history more effective and also in the identification of the correct seizure classification. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Explosive Blast Neuropathology and Seizures

    Directory of Open Access Journals (Sweden)

    S. Krisztian eKovacs

    2014-04-01

    Full Text Available Traumatic brain injury (TBI due to explosive blast exposure is a leading combat casualty. It is also implicated as a key contributor to war related mental health diseases. A clinically important consequence of all types of TBI is a high risk for development of seizures and epilepsy. Seizures have been reported in patients who have suffered blast injuries in the Global War on Terror but the exact prevalence is unknown. The occurrence of seizures supports the contention that explosive blast leads to both cellular and structural brain pathology. Unfortunately, the exact mechanism by which explosions cause brain injury is unclear, which complicates development of meaningful therapies and mitigation strategies. To help improve understanding, detailed neuropathological analysis is needed. For this, histopathological techniques are extremely valuable and indispensable. In the following we will review the pathological results, including those from immunohistochemical and special staining approaches, from recent preclinical explosive blast studies.

  18. Are Epileptic Seizures Quakes of the Brain? An Approach by Means of Nonextensive Tsallis Statistics

    CERN Document Server

    Eftaxias, K; Athanasopoulou, L; Kalimeri, M; Potirakis, S M; Balasis, G

    2011-01-01

    The field of study of complex systems holds that the dynamics of complex systems are founded on universal principles that may used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks, a claim further supported by recent evidence. The purpose of this paper is to suggest a shift in emphasis from the large to the small in the search for a dynamical analogy between seizure and earthquake. Our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. A central property of the epileptic seizure / earthquake generation is the occurrence of coherent large-scale collective behaviour with very rich structure, resulting from repeated nonlinear interactions among the constituents of the system, res...

  19. Brain temporal complexity in explaining the therapeutic and cognitive effects of seizure therapy.

    Science.gov (United States)

    Farzan, Faranak; Atluri, Sravya; Mei, Ye; Moreno, Sylvain; Levinson, Andrea J; Blumberger, Daniel M; Daskalakis, Zafiris J

    2017-04-01

    Over 350 million people worldwide suffer from depression, a third of whom are medication-resistant. Seizure therapy remains the most effective treatment in depression, even when many treatments fail. The utility of seizure therapy is limited due to its cognitive side effects and stigma. The biological targets of seizure therapy remain unknown, hindering design of new treatments with comparable efficacy. Seizures impact the brains temporal dynamicity observed through electroencephalography. This dynamicity reflects richness of information processing across distributed brain networks subserving affective and cognitive processes. We investigated the hypothesis that seizure therapy impacts mood (depressive symptoms) and cognition by modulating brain temporal dynamicity. We obtained resting-state electroencephalography from 34 patients (age = 46.0 ± 14.0, 21 females) receiving two types of seizure treatments-electroconvulsive therapy or magnetic seizure therapy. We used multi-scale entropy to quantify the complexity of the brain's temporal dynamics before and after seizure therapy. We discovered that reduction of complexity in fine timescales underlined successful therapeutic response to both seizure treatments. Greater reduction in complexity of fine timescales in parieto-occipital and central brain regions was significantly linked with greater improvement in depressive symptoms. Greater increase in complexity of coarse timescales was associated with greater decline in cognition including the autobiographical memory. These findings were region and timescale specific. That is, change in complexity in occipital regions (e.g. O2 electrode or right occipital pole) at fine timescales was only associated with change in depressive symptoms, and not change in cognition, and change in complexity in parieto-central regions (e.g. Pz electrode or intra and transparietal sulcus) at coarser timescale was only associated with change in cognition, and not depressive symptoms. Finally

  20. Predicting flow reversals in chaotic natural convection using data assimilation

    Directory of Open Access Journals (Sweden)

    Kameron Decker Harris

    2012-04-01

    Full Text Available A simplified model of natural convection, similar to the Lorenz system, is compared to computational fluid dynamics simulations of a thermosyphon in order to test data assimilation (DA methods and better understand the dynamics of convection. The thermosyphon is represented by a long time flow simulation, which serves as a reference ‘truth’. Forecasts are then made using the Lorenz-like model and synchronised to noisy and limited observations of the truth using DA. The resulting analysis is observed to infer dynamics absent from the model when using short assimilation windows. Furthermore, chaotic flow reversal occurrence and residency times in each rotational state are forecast using analysis data. Flow reversals have been successfully forecast in the related Lorenz system, as part of a perfect model experiment, but never in the presence of significant model error or unobserved variables. Finally, we provide new details concerning the fluid dynamical processes present in the thermosyphon during these flow reversals.

  1. febrile seizures, Tripoli, Libya, knowledge, attitude

    African Journals Online (AJOL)

    kim

    ABSTRACT. Introduction. Febrile seizures are the most common seizure disorder in children. ... Adequate provision of information seemed to reduce this anxiety (2, 16). .... Effects of educational intervention on changing parental practices for.

  2. Temperature, age, and recurrence of febrile seizure

    NARCIS (Netherlands)

    M. van Stuijvenberg (Margriet); E.W. Steyerberg (Ewout); G. Derksen-Lubsen (Gerarda); H.A. Moll (Henriëtte)

    1998-01-01

    textabstractOBJECTIVE: Prediction of a recurrent febrile seizure during subsequent episodes of fever. DESIGN: Study of the data of the temperatures, seizure recurrences, and baseline patient characteristics that were collected at a randomized placebo controlled trial of ibuprofen

  3. Seizures by the clock: Temporal patterns of psychogenic nonepileptic seizures.

    Science.gov (United States)

    Seneviratne, Udaya; Minato, Erica; Paul, Eldho

    2017-09-11

    We hypothesized that (1) the occurrence of psychogenic nonepileptic seizures (PNES) is modulated by the interaction between the 24-hour clock and the sleep-wake cycle and (2) the pattern of modulation in PNES differs from epileptic seizures (ES). We sought to test our hypotheses in a cohort of patients diagnosed with PNES or ES in the setting of an epilepsy monitoring unit (EMU). We retrospectively reviewed consecutive video-EEG (VEEG) recordings of patients who underwent monitoring at the EMU of a tertiary hospital. The seizure type (PNES vs ES), onset time, and the state (sleep vs awake) were tabulated. The relationship between the onset time, the state of arousal, and the occurrence of PNES was determined using logistic regression analysis. To determine if the nature of the relationship between the state of arousal and PNES differed according to the onset time, an interaction between the onset time and the state of arousal was also fitted to the model. We studied a total of 754 seizures (ES, 437; PNES, 317) from 135 patients consisting of 71 (52.6%) females and 64 (47.4%) males with the median age of 39years (range, 18-91). We found a significant association between the state of arousal and PNES with the odds of being PNES four times higher when patients were awake (OR: 4.27, 95% CI: 2.44-7.48; p24-hour time cycle in the generation of PNES. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Perioperative seizures in patients with a history of a seizure disorder.

    Science.gov (United States)

    Niesen, Adam D; Jacob, Adam K; Aho, Lucyna E; Botten, Emily J; Nase, Karen E; Nelson, Julia M; Kopp, Sandra L

    2010-09-01

    The occurrence of perioperative seizures in patients with a preexisting seizure disorder is unclear. There are several factors unique to the perioperative period that may increase a patient's risk of perioperative seizures, including medications administered, timing of medication administration, missed doses of antiepileptic medications, and sleep deprivation. We designed this retrospective chart review to evaluate the frequency of perioperative seizures in patients with a preexisting seizure disorder. We retrospectively reviewed the medical records of all patients with a documented history of a seizure disorder who received an anesthetic between January 1, 2002 and December 31, 2007. Patients excluded from this study include those who had an outpatient procedure or intracranial procedure, ASA classification of V, pregnant women, and patients younger than 2 years of age. The first hospital admission of at least 24 hours during which an anesthetic was provided was identified for each patient. Patient demographics, character of the seizure disorder, details of the surgical procedure, and clinically apparent seizure activity in the perioperative period (within 3 days after the anesthetic) were recorded. During the 6-year study period, 641 patients with a documented seizure disorder were admitted for at least 24 hours after an anesthetic. Twenty-two patients experienced perioperative seizure activity for an overall frequency of 3.4%(95% confidence interval, 2.2%-5.2%). The frequency of preoperative seizures (P seizure (P seizure. As the number of antiepileptic medications increased, so did the frequency of perioperative seizures (P seizures in this patient population. We conclude that the majority of perioperative seizures in patients with a preexisting seizure disorder are likely related to the patient's underlying condition. The frequency of seizures is not influenced by the type of anesthesia or procedure. Because patients with frequent seizures at baseline are

  5. Improving the Horizontal Transport in the Lower Troposphere with Four Dimensional Data Assimilation

    Science.gov (United States)

    The physical processes involved in air quality modeling are governed by dynamically-generated meteorological model fields. This research focuses on reducing the uncertainty in the horizontal transport in the lower troposphere by improving the four dimensional data assimilation (F...

  6. Effect of prophylactic phenobarbital on seizures, encephalopathy ...

    African Journals Online (AJOL)

    Background. Seizures after an asphyxial insult may result in brain damage in neonates. Prophylactic phenobarbital may reduce seizures. Objective. To determine the e€ect of prophylactic phenobarbital on seizures, death and neurological outcome at hospital discharge. Methods. Neonates with base de.cit >16 mmol/l and ...

  7. Treatment of seizures in multiple sclerosis

    NARCIS (Netherlands)

    Koch, Marcus W.; Polman, Susanne K. L.; Uyttenboogaart, Maarten; De Keyser, Jacques

    2009-01-01

    Background Epileptic seizures occur in only a minority of patients with multiple sclerosis (MS), but can have serious consequences. The available literature suggests an association of seizures in MS with cortical and subcortical demyelinating lesions, which suggest that seizures in MS are probably

  8. Assimilation of Unusual Carbon Compounds

    Science.gov (United States)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  9. Data Assimilation in Dynamic Environmental Pollution Modeling

    NARCIS (Netherlands)

    Zhang XF; van Eijkeren JCH; Heemink AW; CWM; TUD

    1995-01-01

    Data-assimilatie methoden zijn bruikbare instrumenten ten behoeve van monitoring en diagnostiek van de milieukwaliteit. Bij deze methoden wordt informatie verkregen uit een milieukwaliteitsmeetnet geincorporeerd met een kwaliteitsmodel. Op deze manier wordt de in de algemene praktijk voorkomende

  10. Recognition Memory After Febrile Seizures

    OpenAIRE

    J Gordon Millichap

    2012-01-01

    Researchers at the Institute of Child Health, London; Epilepsy Center, University of Edinburgh; and Dartmouth Medical School, New Hampshire, US studied memory abilities in 26 children (mean age 23 months, SD 12.6 months) after prolonged febrile seizures (median, 37.5 days), and compared to 37 normal controls.

  11. Viral Infections and Febrile Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-01-01

    Full Text Available The incidence of febrile seizures (FS in a cohort of children, ages 3 months to 5 years, living in a Netherlands province was compared with the incidence of common viral infections reported to a national registry and the results reported from the Department of Medical Microbiology, Public Health Laboratory Friesland, Leeuwarden, The Netherlands.

  12. Hippocampal Abnormalities and Seizure Recurrence

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2006-08-01

    Full Text Available Hippocampal volumetry and T2 relaxometry were performed on 84 consecutive patients (adolescents and adults with partial epilepsy submitted to antiepileptic drug (AED withdrawal after at least 2 years of seizure control, in a study at State University of Campinas-UNICAMP, Brazil.

  13. Data Assimilation Cycling for Weather Analysis

    Science.gov (United States)

    Tran, Nam; Li, Yongzuo; Fitzpatrick, Patrick

    2008-01-01

    This software package runs the atmospheric model MM5 in data assimilation cycling mode to produce an optimized weather analysis, including the ability to insert or adjust a hurricane vortex. The program runs MM5 through a cycle of short forecasts every three hours where the vortex is adjusted to match the observed hurricane location and storm intensity. This technique adjusts the surrounding environment so that the proper steering current and environmental shear are achieved. MM5cycle uses a Cressman analysis to blend observation into model fields to get a more accurate weather analysis. Quality control of observations is also done in every cycle to remove bad data that may contaminate the analysis. This technique can assimilate and propagate data in time from intermittent and infrequent observations while maintaining the atmospheric field in a dynamically balanced state. The software consists of a C-shell script (MM5cycle.driver) and three FORTRAN programs (splitMM5files.F, comRegrid.F, and insert_vortex.F), and are contained in the pre-processor component of MM5 called "Regridder." The model is first initialized with data from a global model such as the Global Forecast System (GFS), which also provides lateral boundary conditions. These data are separated into single-time files using splitMM5.F. The hurricane vortex is then bogussed in the correct location and with the correct wind field using insert_vortex.F. The modified initial and boundary conditions are then recombined into the model fields using comRegrid.F. The model then makes a three-hour forecast. The three-hour forecast data from MM5 now become the analysis for the next short forecast run, where the vortex will again be adjusted. The process repeats itself until the desired time of analysis is achieved. This code can also assimilate observations if desired.

  14. Data assimilation in hydrological modelling

    DEFF Research Database (Denmark)

    Drecourt, Jean-Philippe

    Data assimilation is an invaluable tool in hydrological modelling as it allows to efficiently combine scarce data with a numerical model to obtain improved model predictions. In addition, data assimilation also provides an uncertainty analysis of the predictions made by the hydrological model...... with model non-linearities and biased errors. A literature review analyzes the most popular techniques and their application in hydrological modelling. Since bias is an important problem in groundwater modelling, two bias aware Kalman filters have been implemented and compared using an artificial test case...

  15. Storm surge variational assimilation model

    Directory of Open Access Journals (Sweden)

    Shi-li HUANG

    2010-06-01

    Full Text Available To eliminate errors caused by uncertainty of parameters and further improve capability of storm surge forecasting, the variational data assimilation method is applied to the storm surge model based on unstructured grid with high spatial resolution. The method can effectively improve the forecasting accuracy of storm surge induced by typhoon through controlling wind drag force coefficient parameter. The model is first theoretically validated with synthetic data. Then, the real storm surge process induced by the TC 0515 typhoon is forecasted by the variational data assimilation model, and results show the feasibility of practical application.

  16. Pretreatment seizure semiology in childhood absence epilepsy.

    Science.gov (United States)

    Kessler, Sudha Kilaru; Shinnar, Shlomo; Cnaan, Avital; Dlugos, Dennis; Conry, Joan; Hirtz, Deborah G; Hu, Fengming; Liu, Chunyan; Mizrahi, Eli M; Moshé, Solomon L; Clark, Peggy; Glauser, Tracy A

    2017-08-15

    To determine seizure semiology in children with newly diagnosed childhood absence epilepsy and to evaluate associations with short-term treatment outcomes. For participants enrolled in a multicenter, randomized, double-blind, comparative-effectiveness trial, semiologic features of pretreatment seizures were analyzed as predictors of treatment outcome at the week 16 to 20 visit. Video of 1,932 electrographic absence seizures from 416 participants was evaluated. Median seizure duration was 10.2 seconds; median time between electrographic seizure onset and clinical manifestation onset was 1.5 seconds. For individual seizures and by participant, the most common semiology features were pause/stare (seizure 95.5%, participant 99.3%), motor automatisms (60.6%, 86.1%), and eye involvement (54.9%, 76.5%). The interrater agreement for motor automatisms and eye involvement was good (72%-84%). Variability of semiology features between seizures even within participants was high. Clustering analyses revealed 4 patterns (involving the presence/absence of eye involvement and motor automatisms superimposed on the nearly ubiquitous pause/stare). Most participants experienced more than one seizure cluster pattern. No individual semiologic feature was individually predictive of short-term outcome. Seizure freedom was half as likely in participants with one or more seizure having the pattern of eye involvement without motor automatisms than in participants without this pattern. Almost all absence seizures are characterized by a pause in activity or staring, but rarely is this the only feature. Semiologic features tend to cluster, resulting in identifiable absence seizure subtypes with significant intraparticipant seizure phenomenologic heterogeneity. One seizure subtype, pause/stare and eye involvement but no motor automatisms, is specifically associated with a worse treatment outcome. © 2017 American Academy of Neurology.

  17. Mathematical foundations of hybrid data assimilation from a synchronization perspective

    Science.gov (United States)

    Penny, Stephen G.

    2017-12-01

    The state-of-the-art data assimilation methods used today in operational weather prediction centers around the world can be classified as generalized one-way coupled impulsive synchronization. This classification permits the investigation of hybrid data assimilation methods, which combine dynamic error estimates of the system state with long time-averaged (climatological) error estimates, from a synchronization perspective. Illustrative results show how dynamically informed formulations of the coupling matrix (via an Ensemble Kalman Filter, EnKF) can lead to synchronization when observing networks are sparse and how hybrid methods can lead to synchronization when those dynamic formulations are inadequate (due to small ensemble sizes). A large-scale application with a global ocean general circulation model is also presented. Results indicate that the hybrid methods also have useful applications in generalized synchronization, in particular, for correcting systematic model errors.

  18. Disinhibition-induced transitions between absence and tonic-clonic epileptic seizures

    Science.gov (United States)

    Fan, Denggui; Wang, Qingyun; Perc, Matjaž

    2015-07-01

    Electrophysiological experiments have long revealed the existence of two-way transitions between absence and tonic-clonic epileptic seizures in the cerebral cortex. Based on a modified spatially-extended Taylor & Baier neural field model, we here propose a computational framework to mathematically describe the transition dynamics between these epileptic seizures. We first demonstrate the existence of various transition types that are induced by disinhibitory functions between two inhibitory variables in an isolated Taylor & Baier model. Moreover, we show that these disinhibition-induced transitions can lead to stable tonic-clonic oscillations as well as periodic spike with slow-wave discharges, which are the hallmark of absence seizures. We also observe fascinating dynamical states, such as periodic 2-spike with slow-wave discharges, tonic death, bursting oscillations, as well as saturated firing. Most importantly, we identify paths that represent physiologically plausible transitions between absence and tonic-clonic seizures in the modified spatially-extended Taylor & Baier model.

  19. Chronic metformin treatment facilitates seizure termination.

    Science.gov (United States)

    Yang, Yong; Zhu, Binglin; Zheng, Fangshuo; Li, Yun; Zhang, Yanke; Hu, Yida; Wang, Xuefeng

    2017-03-04

    The AMP-activated protein kinase (AMPK) is a key energy sensor. Its activator metformin could suppress epileptogenesis in the pentylenetetrazol (PTZ) kindling model. However, the effect of metformin on the acute and chronic seizures has not been studied. We first detected the expression of AMPK in the brain tissue of human and mice with chronic seizures, as well as in mice with acute seizures. Second, using behavioral assay and local filed potentials (LFPs) recording, we investigated the effect of chronic metformin treatment on seizures in a acute seizure model and a chronic seizure model. Our results showed that AMPK was expressed in neurons in the epileptic brain. The expression level was decreased in the brain tissue that experienced chronic and acute seizures. In PTZ-induced acute seizures model, behavioral assay showed that chronic metformin treatment decreased the mortality, and LFPs recording showed that chronic metformin treatment shortened the duration of generalized tonic-clonic seizures and prolonged the duration of postictal depression. Moreover, in kainic acid-induced chronic seizures model, LFPs recording showed that chronic metformin treatment shortened the duration of epileptic activity. Our study suggests that chronic metformin treatment could facilitate seizure termination. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Nonlinear analysis of EEG for epileptic seizures

    Energy Technology Data Exchange (ETDEWEB)

    Hively, L.M.; Clapp, N.E.; Daw, C.S.; Lawkins, W.F. [Oak Ridge National Lab., TN (United States); Eisenstadt, M.L. [Knoxville Neurology Clinic, St. Mary`s Medical Center, Knoxville, TN (United States)

    1995-04-01

    We apply chaotic time series analysis (CTSA) to human electroencephalogram (EEG) data. Three epoches were examined: epileptic seizure, non-seizure, and transition from non-seizure to seizure. The CTSA tools were applied to four forms of these data: raw EEG data (e-data), artifact data (f-data) via application of a quadratic zero-phase filter of the raw data, artifact-filtered data (g- data) and that was the residual after subtracting f-data from e-data, and a low-pass-filtered version (h-data) of g-data. Two different seizures were analyzed for the same patient. Several nonlinear measures uniquely indicate an epileptic seizure in both cases, including an abrupt decrease in the time per wave cycle in f-data, an abrupt increase in the Kolmogorov entropy and in the correlation dimension for e-h data, and an abrupt increase in the correlation dimension for e-h data. The transition from normal to seizure state also is characterized by distinctly different trends in the nonlinear measures for each seizure and may be potential seizure predictors for this patient. Surrogate analysis of e-data shows that statistically significant nonlinear structure is present during the non-seizure, transition , and seizure epoches.

  1. Data assimilation making sense of observations

    CERN Document Server

    Lahoz, William; Menard, Richard

    2010-01-01

    In recent years data assimilation methods have been applied to an increasing range of earth science disciplines. This book sets out the theoretical basis of data assimilation with contributions by top international experts in the field.

  2. Data assimilation techniques in modeling ocean processes

    Digital Repository Service at National Institute of Oceanography (India)

    Mahadevan, R.; Fernandes, A.A.; Naqvi, S.W.A.

    control theory method are discussed. Application of data assimilation technique to physical problems governed by linear and nonlinear ordinary differential equations are explained. The formulation of data assimilation technique in one-dimensional models...

  3. Localizing epileptic seizure onsets with Granger causality

    Science.gov (United States)

    Adhikari, Bhim M.; Epstein, Charles M.; Dhamala, Mukesh

    2013-09-01

    Accurate localization of the epileptic seizure onset zones (SOZs) is crucial for successful surgery, which usually depends on the information obtained from intracranial electroencephalography (IEEG) recordings. The visual criteria and univariate methods of analyzing IEEG recordings have not always produced clarity on the SOZs for resection and ultimate seizure freedom for patients. Here, to contribute to improving the localization of the SOZs and to understanding the mechanism of seizure propagation over the brain, we applied spectral interdependency methods to IEEG time series recorded from patients during seizures. We found that the high-frequency (>80 Hz) Granger causality (GC) occurs before the onset of any visible ictal activity and causal relationships involve the recording electrodes where clinically identifiable seizures later develop. These results suggest that high-frequency oscillatory network activities precede and underlie epileptic seizures, and that GC spectral measures derived from IEEG can assist in precise delineation of seizure onset times and SOZs.

  4. Treatment of refractory neonatal seizures with topiramate.

    Science.gov (United States)

    Riesgo, Rudimar; Winckler, Maria Isabel; Ohlweiler, Lygia; Ranzan, Josiane; Becker, Michele; Salvador, Socrates; Magalhaes, Luiza; Ribeiro, Ricardo

    2012-12-01

    The objective of this study is to describe the usefulness of topiramate in refractory neonatal seizures. We reported the clinical off-label use of topiramate in three cases of refractory neonatal seizures of unclear origin with no response to conventional antiepileptic drugs. In all cases, the seizures were completely controlled with adding topiramate. All patients became seizure free during hospitalization and were followed by approximately 1 year after hospital discharge, with monotherapy with topiramate. The clinical off-label use of topiramate in neonatal seizures is still incipient. When searching publications in this matter, only one report was identified. Because of its efficacy for both seizures and neuroprotection, topiramate could be a useful choice in refractory neonatal seizures. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  5. INHIBITORY MOTOR SEIZURES: SEMIOLOGY AND THERAPY

    Directory of Open Access Journals (Sweden)

    K. Yu. Мukhin

    2013-01-01

    Full Text Available The article is devoted to rare and unique type of epileptic seizures – inhibitory motor seizures, characterized by the inability to execute a voluntary movement with preserved consciousness. The exact prevalence of this type of seizures is not known, but many cases are unrecognized or non-correctly diagnosed as Todd's paralysis. Therefore practical doctors should know the clinical and electroencephalographic characteristics of this type of seizures andtake them into account in the differential diagnoses . The authors presented a detailed review of the literature, including the historical data, etiology, pathogenesis and proposed mechanisms of formation of inhibitory motor seizures, clinical and EEG characteristics, therapeutic approaches. Antiepileptic drugs of choice used in the treatment of inhibitory motor seizures are valproic acid (preferably depakine chronosphere – original prolonged form of valproate. The authors also presented their observations of patients with inhibitory motor seizures.

  6. Data assimilation in reservoir management

    NARCIS (Netherlands)

    Rommelse, J.R.

    2009-01-01

    The research presented in this thesis aims at improving computer models that allow simulations of water, oil and gas flows in subsurface petroleum reservoirs. This is done by integrating, or assimilating, measurements into physics-bases models. In recent years petroleum technology has developed

  7. Assimilation of Unusual Carbon Compounds

    NARCIS (Netherlands)

    Middelhoven, W.J.

    2009-01-01

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are

  8. The Phonological Assimilation of Borrowing.

    Science.gov (United States)

    Suleiman, Saleh M.

    Linguistic borrowing from English to Jordanian Arabic at the lexical level is described, focusing on phonology and the extent to which Jordanian Arabic has affected the phonetic structure of English loans assimilated partially or completely into it. Conspicuous distinctive sound features in the two languages that may affect non-native speakers'…

  9. Epileptic Seizures from Abnormal Networks: Why Some Seizures Defy Predictability

    Science.gov (United States)

    2011-12-12

    appeared along this diagonal. The surrogates were generated using the amplitude adjusted Fourier transform algorithm (Theiler et al., 1992). This shuffles ...and (E), respectively. The y-axis represents the fraction of surrogate ( shuffled , see ‘‘Materials and methods’’ section) sequences with a maximal...Wilkinson, S.B., 2001. An introduction to contingent (closed-loop) brain electrical stimulation for seizure blockage, ultra -short-term clinical trials

  10. Prediction of seizure control in non-ketotic hyperglycemic induced seizures

    Directory of Open Access Journals (Sweden)

    Pratipanawatr Thongchai

    2009-12-01

    Full Text Available Abstract Background To study the factors predictive for seizure control in non-ketotic hyperglycemic induced seizures (NKHS. Methods We studied 21 patients who were clinically diagnosed as NKHS at Khon Kaen University hospital, Thailand. Multiple linear regression analysis was used to identify the factors predictive for seizure control. Results Most patients had no previous history of diabetes and presented with repetitive partial seizures. The mean number of seizure attacks was 45 times prior to admission. The average duration to terminate seizure was 36 hours and significantly predicted by frequency of seizures (estimate 0.9, p value 0.013. Conclusion Frequency of seizures is the only predictive factor for the success of seizure control in NKHS.

  11. Mining continuous intracranial EEG in focal canine epilepsy: Relating interictal bursts to seizure onsets.

    Science.gov (United States)

    Davis, Kathryn A; Ung, Hoameng; Wulsin, Drausin; Wagenaar, Joost; Fox, Emily; Patterson, Ned; Vite, Charles; Worrell, Gregory; Litt, Brian

    2016-01-01

    Brain regions are localized for resection during epilepsy surgery based on rare seizures observed during a short period of intracranial electroencephalography (iEEG) monitoring. Interictal epileptiform bursts, which are more prevalent than seizures, may provide complementary information to aid in epilepsy evaluation. In this study, we leverage a long-term iEEG dataset from canines with naturally occurring epilepsy to investigate interictal bursts and their electrographic relationship to seizures. Four dogs were included in this study, each monitored previously with continuous iEEG for periods of 475.7, 329.9, 45.8, and 451.8 days, respectively, for a total of >11,000 h. Seizures and bursts were detected and validated by two board-certified epileptologists. A published Bayesian model was applied to analyze the dynamics of interictal epileptic bursts on EEG and compare them to seizures. In three dogs, bursts were stereotyped and found to be statistically similar to periods before or near seizure onsets. Seizures from one dog during status epilepticus were markedly different from other seizures in terms of burst similarity. Shorter epileptic bursts explored in this work have the potential to yield significant information about the distribution of epileptic events. In our data, bursts are at least an order of magnitude more prevalent than seizures and occur much more regularly. Our finding that bursts often display pronounced similarity to seizure onsets suggests that they contain relevant information about the epileptic networks from which they arise and may aide in the clinical evaluation of epilepsy in patients. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

  12. Mining Continuous Intracranial EEG in Focal Canine Epilepsy: Relating Interictal Bursts to Seizure Onsets

    Science.gov (United States)

    Davis, Kathryn A.; Ung, Hoameng; Wulsin, Drausin; Wagenaar, Joost; Fox, Emily; Patterson, Ned; Vite, Charles; Worrell, Gregory; Litt, Brian

    2016-01-01

    Objective Brain regions are localized for resection during epilepsy surgery based upon rare seizures observed during a short time period of intracranial EEG (iEEG) monitoring. Interictal epileptiform bursts, which are more prevalent than seizures, may provide complementary information to aid in epilepsy evaluation. In this study, we leverage a long-term iEEG dataset from canines with naturally occurring epilepsy to investigate interictal bursts and their electrographic relationship to seizures. Methods Four dogs were included in this study, each previously monitored with continuous iEEG for periods of 475.7, 329.9, 45.8, and 451.8 days respectively for a total of over 11,000 hours. Seizures and bursts were detected and validated by two board-certified epileptologists. A published Bayesian model was applied to analyze the dynamics of interictal epileptic bursts on EEG and compare them to seizures. Results In three dogs, bursts were stereotyped and found to be statistically similar to periods before or near seizure onsets. Seizures from one dog during status epilepticus were markedly different than other seizures in terms of burst similarity. Significance Shorter epileptic bursts explored in this work have the potential to yield significant information about the distribution of epileptic events. In our data, bursts are at least an order of magnitude more prevalent than seizures and occur much more regularly. Our finding that bursts often display pronounced similarity to seizure onsets suggests that they contain relevant information about the epileptic networks from which they arise and may aide in the clinical evaluation of epilepsy in patients. PMID:26608448

  13. A novel seizure detection algorithm informed by hidden Markov model event states

    Science.gov (United States)

    Baldassano, Steven; Wulsin, Drausin; Ung, Hoameng; Blevins, Tyler; Brown, Mesha-Gay; Fox, Emily; Litt, Brian

    2016-06-01

    Objective. Recently the FDA approved the first responsive, closed-loop intracranial device to treat epilepsy. Because these devices must respond within seconds of seizure onset and not miss events, they are tuned to have high sensitivity, leading to frequent false positive stimulations and decreased battery life. In this work, we propose a more robust seizure detection model. Approach. We use a Bayesian nonparametric Markov switching process to parse intracranial EEG (iEEG) data into distinct dynamic event states. Each event state is then modeled as a multidimensional Gaussian distribution to allow for predictive state assignment. By detecting event states highly specific for seizure onset zones, the method can identify precise regions of iEEG data associated with the transition to seizure activity, reducing false positive detections associated with interictal bursts. The seizure detection algorithm was translated to a real-time application and validated in a small pilot study using 391 days of continuous iEEG data from two dogs with naturally occurring, multifocal epilepsy. A feature-based seizure detector modeled after the NeuroPace RNS System was developed as a control. Main results. Our novel seizure detection method demonstrated an improvement in false negative rate (0/55 seizures missed versus 2/55 seizures missed) as well as a significantly reduced false positive rate (0.0012 h versus 0.058 h-1). All seizures were detected an average of 12.1 ± 6.9 s before the onset of unequivocal epileptic activity (unequivocal epileptic onset (UEO)). Significance. This algorithm represents a computationally inexpensive, individualized, real-time detection method suitable for implantable antiepileptic devices that may considerably reduce false positive rate relative to current industry standards.

  14. Ocean Data Assimilation in Support of Climate Applications: Status and Perspectives.

    Science.gov (United States)

    Stammer, D; Balmaseda, M; Heimbach, P; Köhl, A; Weaver, A

    2016-01-01

    Ocean data assimilation brings together observations with known dynamics encapsulated in a circulation model to describe the time-varying ocean circulation. Its applications are manifold, ranging from marine and ecosystem forecasting to climate prediction and studies of the carbon cycle. Here, we address only climate applications, which range from improving our understanding of ocean circulation to estimating initial or boundary conditions and model parameters for ocean and climate forecasts. Because of differences in underlying methodologies, data assimilation products must be used judiciously and selected according to the specific purpose, as not all related inferences would be equally reliable. Further advances are expected from improved models and methods for estimating and representing error information in data assimilation systems. Ultimately, data assimilation into coupled climate system components is needed to support ocean and climate services. However, maintaining the infrastructure and expertise for sustained data assimilation remains challenging.

  15. Seizure characteristics of epilepsy in childhood after acute encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Ito, Yuji; Natsume, Jun; Kidokoro, Hiroyuki; Ishihara, Naoko; Azuma, Yoshiteru; Tsuji, Takeshi; Okumura, Akihisa; Kubota, Tetsuo; Ando, Naoki; Saitoh, Shinji; Miura, Kiyokuni; Negoro, Tamiko; Watanabe, Kazuyoshi; Kojima, Seiji

    2015-08-01

    The aim of this study was to clarify characteristics of post-encephalopathic epilepsy (PEE) in children after acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), paying particular attention to precise diagnosis of seizure types. Among 262 children with acute encephalopathy/encephalitis registered in a database of the Tokai Pediatric Neurology Society between 2005 and 2012, 44 were diagnosed with AESD according to the clinical course and magnetic resonance imaging (MRI) findings and were included in this study. Medical records were reviewed to investigate clinical data, MRI findings, neurologic outcomes, and presence or absence of PEE. Seizure types of PEE were determined by both clinical observation by pediatric neurologists and ictal video-electroencephalography (EEG) recordings. Of the 44 patients after AESD, 10 (23%) had PEE. The period between the onset of encephalopathy and PEE ranged from 2 to 39 months (median 8.5 months). Cognitive impairment was more severe in patients with PEE than in those without. Biphasic seizures and status epilepticus during the acute phase of encephalopathy did not influence the risk of PEE. The most common seizure type of PEE on clinical observation was focal seizures (n = 5), followed by epileptic spasms (n = 4), myoclonic seizures (n = 3), and tonic seizures (n = 2). In six patients with PEE, seizures were induced by sudden unexpected sounds. Seizure types confirmed by ictal video-EEG recordings were epileptic spasms and focal seizures with frontal onset, and all focal seizures were startle seizures induced by sudden acoustic stimulation. Intractable daily seizures remain in six patients with PEE. We demonstrate seizure characteristics of PEE in children after AESD. Epileptic spasms and startle focal seizures are common seizure types. The specific seizure types may be determined by the pattern of diffuse subcortical white matter injury in AESD and age-dependent reorganization of the brain

  16. Gap junctions and epileptic seizures--two sides of the same coin?

    Directory of Open Access Journals (Sweden)

    Vladislav Volman

    Full Text Available Electrical synapses (gap junctions play a pivotal role in the synchronization of neuronal ensembles which also makes them likely agonists of pathological brain activity. Although large body of experimental data and theoretical considerations indicate that coupling neurons by electrical synapses promotes synchronous activity (and thus is potentially epileptogenic, some recent evidence questions the hypothesis of gap junctions being among purely epileptogenic factors. In particular, an expression of inter-neuronal gap junctions is often found to be higher after the experimentally induced seizures than before. Here we used a computational modeling approach to address the role of neuronal gap junctions in shaping the stability of a network to perturbations that are often associated with the onset of epileptic seizures. We show that under some circumstances, the addition of gap junctions can increase the dynamical stability of a network and thus suppress the collective electrical activity associated with seizures. This implies that the experimentally observed post-seizure additions of gap junctions could serve to prevent further escalations, suggesting furthermore that they are a consequence of an adaptive response of the neuronal network to the pathological activity. However, if the seizures are strong and persistent, our model predicts the existence of a critical tipping point after which additional gap junctions no longer suppress but strongly facilitate the escalation of epileptic seizures. Our results thus reveal a complex role of electrical coupling in relation to epileptiform events. Which dynamic scenario (seizure suppression or seizure escalation is ultimately adopted by the network depends critically on the strength and duration of seizures, in turn emphasizing the importance of temporal and causal aspects when linking gap junctions with epilepsy.

  17. Emergent diagnostic testing for pediatric nonfebrile seizures.

    Science.gov (United States)

    Strobel, Ashley M; Gill, Vikramjit S; Witting, Michael D; Teshome, Getachew

    2015-09-01

    Guidelines from the American Academy of Neurology recommend laboratory studies or computed tomography (CT) for children who experience a nonfebrile seizure if anything in their history suggests a clinically significant abnormality. To ascertain if any patient or seizure characteristics are associated with a greater likelihood that laboratory studies or CT scan will yield clinically significant results. This retrospective case series reviewed 93 children with nonfebrile seizure, who were evaluated in an urban pediatric emergency department (ED) between July 2007 and June 2011. Laboratory studies were performed in 87% of the study group; 7% of those tests gave clinically significant results. Computed tomographic scans were obtained in 35% of our patients; 9% showed clinically significant findings. Presence of an active seizure in the ED or a first nonfebrile seizure had an 8% and 11% difference, respectively, for clinically significant laboratory abnormality. Children younger than 2 years showed a 7% difference of clinically significant laboratory abnormality. This study did not identify statistically significant predictors of laboratory or CT abnormalities for children with nonfebrile seizure presenting to the ED. Age less than 2years, having an active seizure in the ED, and experiencing a first-time seizure showed a trend toward an increased yield of laboratory testing. In accordance with the American Academy of Neurology guidelines, we conclude that the history of a child's present illness preceding the nonfebrile seizure, not characteristics of the seizure, should be used to determine the need for further testing. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Clinical Features of Late-Onset Seizures

    Directory of Open Access Journals (Sweden)

    Eda Derle

    2016-12-01

    Full Text Available INTRODUCTION: We aimed to evaluate the types of seziures, etiological factors, effectiveness and adverse effects of antiepileptic treatment in the elderly. METHODS: We evaluated the medical data of the 138 patients, who had their first seizure above the age of 65, and admitted to our clinic between years 2011-2013. We determined the type of seizure, etiological factors, seizure reccurence, antiepileptic treatment, adverse effects of the treatment and the rate of patients who were seizure free at the last visit RESULTS: In the 138 patients, whose mean age was 75,62±7.2 years at the time of first seizure, we found the most common seizure type was generalized seizure and the most common etiologic factor was cerebrovascular diseases. Levetirasetam was the most used antiepileptic drug, and for the overall group the rate of adverse effect of the antiepileptic drugs were 20.3%. At the last visit, 89.9% of the patients were seizure free with a mean time of 17.8±22.7 months. DISCUSSION AND CONCLUSION: In conclusion, symptomatic seizures were common in elderly with better response to antiepileptic drugs and usually monotheraphy was sufficent for maintanence of the seizure free period. The side effects and drug interactionsmust be taken into account while choosing the antiepileptic treatment, since the comorbid diseases and multiple drug usage is common in elderly

  19. Smartphone applications for seizure management.

    Science.gov (United States)

    Pandher, Puneet Singh; Bhullar, Karamdeep Kaur

    2016-06-01

    Technological advancements continue to provide innovative ways of enhancing patient care in medicine. In particular, the growing popularity of smartphone technology has seen the recent emergence of a myriad of healthcare applications (or apps) that promise to help shape the way in which health information is delivered to people worldwide. While limited research already exists on a range of such apps, our study is the first to examine the salient features of smartphone applications as they apply to the area of seizure management. For the purposes of this review, we conducted a search of the official online application stores of the five major smartphone platforms: iPhone, Android, Blackberry, Windows Mobile and Nokia-Symbian. Apps were included if they reported to contain some information or tools relating to seizure management and excluded if they were aimed exclusively at health professionals. A total of 28 applications met these criteria. Overall, we found an increasing number of epilepsy apps available on the smartphone market, but with only a minority offering comprehensive educational information alongside tools such as seizure diaries, medication tracking and/or video recording. © The Author(s) 2014.

  20. New-onset seizures in pediatric emergency.

    Science.gov (United States)

    Chen, Chun-Yu; Chang, Yu-Jun; Wu, Han-Ping

    2010-04-01

    Seizures account for 1% of all pediatric emergency department (ED) visits. The aim of this study was to analyze the clinical spectrum and prevalence rates of various etiologies in children with a first attack of acute seizure disorder in the ED. We evaluated 319 children who presented to the ED at the Changhua Children's Hospital with a first attack of seizure disorder from 2005 to 2007. Variables including demographics, clinical presentations, laboratory tests, brain imaging studies, electroencephalography, diagnoses and hospital course were compared between patients with seizures and fever, and patients with seizures without fever. These variables were also compared between patients with simple and complex febrile seizures and among different age groups. Among these 319 patients, 218 (68%) presented with seizures and fever and 299 (94%) children were younger than 6 years of age. Generalized tonic-clonic seizures were the most common type (71.2%). Febrile seizures (62.1%) were the main etiology of the first seizure (p Seizures caused by severe electrolyte imbalance or hypoglycemia were noted in three patients. Abnormal brain images were noted in 16 (26%) of 61 patients, most (12/16, 75%) of whom had abnormal histories and physical or neurologic examinations. Primary care pediatricians should evaluate children presenting to the ED with a first seizure for age, coexistence of fever, seizure type, associated symptoms and history of head injury. We suggest that electrolytes, blood sugar and emergent brain imaging studies should be arranged based on detailed history-taking and thorough physical examinations, but should not be performed routinely. Copyright 2010 Taiwan Pediatric Association. Published by Elsevier B.V. All rights reserved.

  1. Satellite radiance data assimilation for binary tropical cyclone cases over the western North Pacific

    Science.gov (United States)

    Choi, Yonghan; Cha, Dong-Hyun; Lee, Myong-In; Kim, Joowan; Jin, Chun-Sil; Park, Sang-Hun; Joh, Min-Su

    2017-06-01

    A total of three binary tropical cyclone (TC) cases over the Western North Pacific are selected to investigate the effects of satellite radiance data assimilation on analyses and forecasts of binary TCs. Two parallel cycling experiments with a 6 h interval are performed for each binary TC case, and the difference between the two experiments is whether satellite radiance observations are assimilated. Satellite radiance observations are assimilated using the Weather Research and Forecasting Data Assimilation (WRFDA)'s three-dimensional variational (3D-Var) system, which includes the observation operator, quality control procedures, and bias correction algorithm for radiance observations. On average, radiance assimilation results in slight improvements of environmental fields and track forecasts of binary TC cases, but the detailed effects vary with the case. When there is no direct interaction between binary TCs, radiance assimilation leads to better depictions of environmental fields, and finally it results in improved track forecasts. However, positive effects of radiance assimilation on track forecasts can be reduced when there exists a direct interaction between binary TCs and intensities/structures of binary TCs are not represented well. An initialization method (e.g., dynamic initialization) combined with radiance assimilation and/or more advanced DA techniques (e.g., hybrid method) can be considered to overcome these limitations.

  2. Epileptic Seizure Classification of EEGs using Time-Frequency Analysis based Multiscale Radial Basis Functions.

    Science.gov (United States)

    Li, Yang; Wang, Xu; Luo, Lin; Li, Ke; Yang, Xiao; Guo, Qi

    2017-03-10

    The automatic detection of epileptic seizures from electroencephalography (EEG) signals is crucial for the localization and classification of epileptic seizure activity. However, seizure processes are typically dynamic and nonstationary, and thus distinguishing rhythmic discharges from nonstationary processes is one of the challenging problems. In this paper, an adaptive and localized time-frequency representation in EEG signals is proposed by means of multiscale radial basis functions (MRBF) and a modified particle swarm optimization (MPSO) to improve both time and frequency resolution simultaneously, which is a novel MRBF-MPSO framework of the time-frequency feature extraction for epileptic EEG signals. The dimensionality of extracted features can be greatly reduced by the principle component analysis (PCA) algorithm before the most discriminative features selected are fed into a SVM classifier with the radial basis function (RBF) in order to separate epileptic seizure from seizure-free EEG signals. The classification performance of the proposed method has been evaluated by using several state-of-art feature extraction algorithms and other five different classifiers like linear discriminant analysis (LDA), and Logistic Regression (LR). The experimental results indicate that the proposed MRBF-MPSO-SVM classification method outperforms competing techniques in terms of classification accuracy, and show the effectiveness of the proposed method for classification of seizure epochs and seizure-free epochs.

  3. You are not always what we think you eat: selective assimilation across multiple whole-stream isotopic tracer studies

    Science.gov (United States)

    W. K. Dodds; S. M. Collins; S. K. Hamilton; J. L. Tank; S. Johnson; J. R. Webster; K. S. Simon; M. R. Whiles; H. M. Rantala; W. H. McDowell; S. D. Peterson; T. Riis; C. L. Crenshaw; S. A. Thomas; P. B. Kristensen; B. M. Cheever; A. S. Flecker; N. A. Griffiths; T. Crowl; E. J. Rosi-Marshall; R. El-Sabaawi; E. Martí

    2014-01-01

    Analyses of 21 15N stable isotope tracer experiments, designed to examine food web dynamics in streams around the world, indicated that the isotopic composition of food resources assimilated by primary consumers (mostly invertebrates) poorly reflected the presumed food sources. Modeling indicated that consumers assimilated only 33–50% of the N...

  4. News for assimilation or integration

    Science.gov (United States)

    Alencar, Amanda; Deuze, Mark

    2017-04-01

    This study investigates the functions of news media in shaping acculturation experiences of new economic and refugee immigrants in the Netherlands and Spain. Focus group data revealed that consumption of host country news media was mainly connected to immigrants' deliberate strategies to assimilate the culture, politics and language of the host society, while exposure to transnational news was viewed in terms of strategies of integration in both countries. We also observed that participants' educational background and language skills combined with their perceptions of the host country's news have an impact on the use they make of news for assimilating and/or integrating into the host society. Finally, important sociopolitical conditions of the context influenced the ways participants use the news media in their process of acculturation.

  5. Febrile seizures and risk of schizophrenia

    DEFF Research Database (Denmark)

    Vestergaard, Mogens; Pedersen, Carsten Bøcker; Christensen, Jakob

    2005-01-01

    BACKGROUND: Febrile seizure is a benign condition for most children, but experiments in animals and neuroimaging studies in humans suggest that some febrile seizures may damage the hippocampus, a brain area of possible importance in schizophrenia. METHODS: A population-based cohort of all childre...... among persons with a history of febrile seizures. The association may be due to a damaging effect of prolonged febrile seizures on the developing brain, shared etiological factors, or confounding by unmeasured factors......BACKGROUND: Febrile seizure is a benign condition for most children, but experiments in animals and neuroimaging studies in humans suggest that some febrile seizures may damage the hippocampus, a brain area of possible importance in schizophrenia. METHODS: A population-based cohort of all children...

  6. Overview: definitions and classifications of seizure emergencies.

    Science.gov (United States)

    Pellock, John M

    2007-05-01

    Seizure emergencies are potentially life-threatening events that are under-recognized. Status epilepticus is associated with considerable rates of morbidity and mortality. Experts currently believe that any episode of seizure activity lasting 5 minutes or longer should be considered status epilepticus. Treatment should be initiated as early as possible; evidence has shown that once seizures persist for 5 to 10 minutes, they are unlikely to stop on their own in the subsequent few minutes. Prehospital treatment with benzodiazepines has been shown to reduce seizure activity significantly compared with seizures that remain untreated until the patient reaches the emergency department. The consequences of delayed treatment of status epilepticus include a serious risk of subsequent prolonged seizure activity or epileptogenesis, memory deficits, and learning difficulties. The importance of timely intervention in generalized tonic-clonic status epilepticus must be emphasized. Recent research has found that emergency department personnel fail to recognize the condition in children in 34% of cases.

  7. Channel selection for automatic seizure detection

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas; Kjaer, Troels Wesenberg; Madsen, Rasmus Elsborg

    2012-01-01

    Objective: To investigate the performance of epileptic seizure detection using only a few of the recorded EEG channels and the ability of software to select these channels compared with a neurophysiologist. Methods: Fifty-nine seizures and 1419 h of interictal EEG are used for training and testing...... of an automatic channel selection method. The characteristics of the seizures are extracted by the use of a wavelet analysis and classified by a support vector machine. The best channel selection method is based upon maximum variance during the seizure. Results: Using only three channels, a seizure detection...... sensitivity of 96% and a false detection rate of 0.14/h were obtained. This corresponds to the performance obtained when channels are selected through visual inspection by a clinical neurophysiologist, and constitutes a 4% improvement in sensitivity compared to seizure detection using channels recorded...

  8. Assimilation of remote sensing observations into a sediment transport model of China's largest freshwater lake: spatial and temporal effects.

    Science.gov (United States)

    Zhang, Peng; Chen, Xiaoling; Lu, Jianzhong; Zhang, Wei

    2015-12-01

    Numerical models are important tools that are used in studies of sediment dynamics in inland and coastal waters, and these models can now benefit from the use of integrated remote sensing observations. This study explores a scheme for assimilating remotely sensed suspended sediment (from charge-coupled device (CCD) images obtained from the Huanjing (HJ) satellite) into a two-dimensional sediment transport model of Poyang Lake, the largest freshwater lake in China. Optimal interpolation is used as the assimilation method, and model predictions are obtained by combining four remote sensing images. The parameters for optimal interpolation are determined through a series of assimilation experiments evaluating the sediment predictions based on field measurements. The model with assimilation of remotely sensed sediment reduces the root-mean-square error of the predicted sediment concentrations by 39.4% relative to the model without assimilation, demonstrating the effectiveness of the assimilation scheme. The spatial effect of assimilation is explored by comparing model predictions with remotely sensed sediment, revealing that the model with assimilation generates reasonable spatial distribution patterns of suspended sediment. The temporal effect of assimilation on the model's predictive capabilities varies spatially, with an average temporal effect of approximately 10.8 days. The current velocities which dominate the rate and direction of sediment transport most likely result in spatial differences in the temporal effect of assimilation on model predictions.

  9. 19 CFR 162.22 - Seizure of conveyances.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Seizure of conveyances. 162.22 Section 162.22... TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Seizures § 162.22 Seizure of conveyances. (a) General applicability. If it shall appear to any officer authorized to board conveyances and make seizures that there...

  10. Seizure Recognition and Observation: A Guide for Allied Health Professionals.

    Science.gov (United States)

    Epilepsy Foundation of America, Landover, MD.

    Intended for allied health professionals, this guide provides information on seizure recognition and classification to help them assist the patient, the family, and the treating physician in obtaining control of epileptic seizures. A section on seizure recognition describes epilepsy and seizures, covering seizure classification and the causes of…

  11. Emergency Management of Seizures in the School Setting

    Science.gov (United States)

    O'Dell, Christine; O'Hara, Kathryn; Kiel, Sarah; McCullough, Kathleen

    2007-01-01

    Effective seizure management in the school setting is a critical issue for students with seizures, as well as their parents, classmates, and school personnel. The unpredictable nature of seizures and the potential outcomes of experiencing a seizure in school are sources of anxiety for students with seizures. The ability to respond appropriately to…

  12. [First generalized tonic-clonic seizure].

    Science.gov (United States)

    Realfsen, Martha Seim; Bø, Siri M Hylleraas; Lossius, Morten I; Nakken, Karl O

    2015-08-11

    First onset of a generalized tonic-clonic seizure is a frequent reason for hospital admissions. This article aims to provide a brief overview of the epidemiology, etiology, investigation and treatment of a first generalized tonic-clonic seizure. The review is based on a discretionary sample of English-language articles found through a search in PubMed, and the authors' own clinical experience. A first generalized tonic-clonic seizure is traditionally divided into either a provoked or an unprovoked seizure. Provoked seizures occur in close temporal relationship to a systemic disorder or to a brain insult, for example a stroke or a head trauma. Unprovoked seizures occur in the absence of such factors. The incidence of provoked and unprovoked seizures is 35/100.000 person years and 50/100,000 person years, respectively. The occurrence is influenced by genetic and lifestyle factors. The hospital assessment includes a thorough case history, a somatic and neurological examination, ECG, standard EEG, and cerebral MRI. An immediate cerebral CT is often carried out. In case of provoked seizures, both treatment and estimation of the recurrence risk depends on the underlying cause. Antiepileptic drug treatment initiated after a first unprovoked seizure may reduce the risk of seizure recurrence. However, no long term risk reduction has been shown compared to delaying treatment until after a second seizure. Patients who experience a first generalized tonic-clonic seizure are a heterogenous group, and a thorough diagnostic assessment is necessary in order to provide tailored treatment and a reliable prognosis.

  13. Orgasm Induced Seizures: A Rare Phenomenon

    Science.gov (United States)

    Chaukimath, SP; Patil, PS

    2015-01-01

    A variety of stimuli can cause reflex seizures, Some triggers include light, music and cognitive phenomenon. There are case reports however where the phenomenon of sexual activity has been a trigger for epileptic seizures. Most of these cases reported are in women so far, and were found to be localized to right cerebral hemisphere. We report a case of a 36-year-old male with orgasm-induced seizures, with other atypical features compared to majority of previous reports. PMID:27057393

  14. Orgasm Induced Seizures: A Rare Phenomenon

    African Journals Online (AJOL)

    2006;47:2193‑7. 6. Janszky J, Ebner A, Szupera Z, Schulz R, Hollo A,. Szücs A, et al. Orgasmic aura – A report of seven cases. Seizure. 2004;13:441‑4. 7. Sengupta A, Mahmoud A, Tun SZ, Goulding P. Orgasm‑induced seizures: Male studied with ictal electroencephalography. Seizure 2010;19:306‑9. 8. Bancaud J, Favel P, ...

  15. An ocean modelling and assimilation guide to using GOCE geoid products

    DEFF Research Database (Denmark)

    Haines, K.; Johannessen, J. A.; Knudsen, Per

    2011-01-01

    the combination of the geoid information with time-mean sea level information derived from satellite altimeter data, to construct a mean dynamic topography (MDT), and considers how this complements the time-varying sea level anomaly, also available from the satellite altimeter. We particularly consider...... for assimilating the resulting dynamic topography information into an ocean circulation model using three different operational forecasting and data assimilation systems. We look at methods used for assimilating altimeter anomaly data in the absence of a suitable geoid, and then discuss different approaches which...... have been tried for assimilating the additional geoid information. We review the problems that have been encountered and the lessons learned in order the help future users. Finally we present some results from the use of GRACE geoid information in the operational oceanography community and discuss...

  16. Assimilation of ocean sea-surface height observations of mesoscale eddies

    Science.gov (United States)

    Weiss, Jeffrey B.; Grooms, Ian

    2017-12-01

    Mesoscale eddies are one of the dominant sources of variability in the world's oceans. With eddy-resolving global ocean models, it becomes important to assimilate observations of mesoscale eddies to correctly represent the state of the mesoscale. Here, we investigate strategies for assimilating a reduced number of sea-surface height observations by focusing on the coherent mesoscale eddies. The study is carried out in an idealized perfect-model framework using two-layer forced quasigeostrophic dynamics, which captures the dominant dynamics of ocean mesoscale eddies. We study errors in state-estimation as well as error growth in forecasts and find that as fewer observations are assimilated, assimilating at vortex locations results in reduced state estimation and forecast errors.

  17. Validation of three-dimensional data assimilation and reanalysis of radiation belt electrons

    Science.gov (United States)

    Cervantes-Villa, Juan Sebastian; Shprits, Yuri Y.

    2017-04-01

    Satellite observations are often incomplete and inaccurate and may have only limited spatial coverage. However, through data assimilation they can be blended with information from physics-based models, in order to fill gaps and lead to a better understanding of the underlying dynamical processes. Data assimilation methods have been extensively used to analyze and predict meteorological, oceanographic, and climate processes. With the advent of space-borne observational data and the development of more sophisticated space-physics models, dynamical processes in the Earth's radiation belts can be analyzed and assessed using data assimilation methods. In this study, reanalysis of radiation belt electrons is achieved through data assimilation of Van Allen Probes mission and Geostationary Operational Environmental Satellite with the 3D Versatile Electron Radiation Belt using a split-operator Kalman filter technique. Results are statistically validated for several field models and boundary conditions. Sensitivity of the reanalysis electron flux to available spacecraft data is also assessed.

  18. Diagnosing Functional Seizures in Children and Adolescent

    DEFF Research Database (Denmark)

    Wichaidit, Bianca Taaning; Rask, Charlotte Ulrikka; Ostergaard, John R

    2014-01-01

    Functional seizures (FS) is a condition where the child experiences seizure-like events, without abnormal electrical discharge as measured by EEG, and with high risk of misdiagnosis. Diagnosing FS contains: 1) video-EEG, 2) anamnestic evaluation, focusing on the presence of psychosocial stressors......, psychiatric co-morbidity and functional symptoms other than FS, and 3) evaluation of seizure characteristics such as long duration, seizure initiation during wakefulness and in the presence of witnesses asynchronous movements, and no incontinence, tongue bite and injury related to the event....

  19. Myoclonic Absence Seizures in Dravet Syndrome.

    Science.gov (United States)

    Myers, Kenneth A; Scheffer, Ingrid E

    2017-05-01

    Dravet syndrome is a developmental and epileptic encephalopathy that occurs as a result of SCN1A mutations in more than 80% of affected individuals. The core clinical features of Dravet syndrome include febrile and afebrile seizures beginning before 12 months; multiple seizure types, usually medically refractory, including hemiclonic, generalized tonic-clonic, focal impaired awareness, myoclonic, and absence seizures; status epilepticus; and normal early development with plateau or regression by age two years. Myoclonic absence seizures have not previously been described. This 20-year-old man had infantile-onset epilepsy with the classical clinical features of Dravet syndrome and a de novo A1326P SCN1A mutation. By five years of age, photosensitive myoclonic absence seizures had become his dominant seizure type, occurring up to 20 times per day. The seizures were refractory to multiple antiepileptic medications and a vagus nerve stimulator. Although photosensitivity is well recognized in Dravet syndrome, myoclonic absence seizures have not been previously reported. This rare seizure type may be underreported in Dravet syndrome, as the myoclonic features may be subtle and can be missed if thorough history taking and video recordings are not available. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Flumazenil and seizures: analysis of 43 cases.

    Science.gov (United States)

    Spivey, W H

    1992-01-01

    Flumazenil is a new drug indicated for the reversal of the sedative effects of benzodiazepines mediated at the benzodiazepine-receptor site. Worldwide sources to date have disclosed 43 cases of seizures related, at least temporally, to the intravenous administration of flumazenil. There was no apparent relationship between the dose of flumazenil and the development of seizures, which occurred at doses ranging from 0.2 to 10.0 mg. The seizures were not considered to be a toxic effect of flumazenil, but many of them probably were due to an unmasking of the anticonvulsant effect of the previously used benzodiazepine or to a severe benzodiazepine-withdrawal syndrome. Eighteen (42%) of the patients had ingested overdoses of cyclic antidepressants, which were considered responsible for the seizures. In addition to patients with concurrent cyclic antidepressant poisoning, high-risk populations include patients who have been treated with benzodiazepines for a seizure disorder or an acute convulsive episode, patients with concurrent major sedative-hypnotic drug withdrawal, patients who have recently been treated with repeated doses of parenteral benzodiazepines, and overdose patients with myoclonic jerking or seizure activity before flumazenil administration. To minimize the likelihood of a seizure, it is recommended that flumazenil not be administered to patients who have used benzodiazepines for the treatment of seizure disorders or to patients who have ingested drugs (eg, cyclic antidepressants, cocaine, lithium, methylxanthines, isoniazid, propoxyphene, monoamine oxidase inhibitors, buproprion HCl, and cyclosporine) that place them at risk for the development of seizures.

  1. Naming game with biased assimilation over adaptive networks

    Science.gov (United States)

    Fu, Guiyuan; Zhang, Weidong

    2018-01-01

    The dynamics of two-word naming game incorporating the influence of biased assimilation over adaptive network is investigated in this paper. Firstly an extended naming game with biased assimilation (NGBA) is proposed. The hearer in NGBA accepts the received information in a biased manner, where he may refuse to accept the conveyed word from the speaker with a predefined probability, if the conveyed word is different from his current memory. Secondly, the adaptive network is formulated by rewiring the links. Theoretical analysis is developed to show that the population in NGBA will eventually reach global consensus on either A or B. Numerical simulation results show that the larger strength of biased assimilation on both words, the slower convergence speed, while larger strength of biased assimilation on only one word can slightly accelerate the convergence; larger population size can make the rate of convergence slower to a large extent when it increases from a relatively small size, while such effect becomes minor when the population size is large; the behavior of adaptively reconnecting the existing links can greatly accelerate the rate of convergence especially on the sparse connected network.

  2. Semiology of temporal lobe seizures: value in lateralizing the seizure focus.

    Science.gov (United States)

    Marks, W J; Laxer, K D

    1998-07-01

    To determine the lateralizing value of the clinical manifestations of seizures in patients with temporal lobe epilepsy (TLE), we made a retrospective videotape analysis of complex partial seizures (CPS) in 55 patients who underwent temporal lobectomy and were seizure-free postoperatively for >2 years. Blinded to clinical details, we reviewed videotapes from video-EEG telemetry monitoring with attention paid to seizure semiology. Useful lateralizing features included unilateral clonic activity (with the seizure focus contralateral in all patients), unilateral dystonic or tonic posturing (with the seizure focus contralateral in 90 and 86%, respectively), unilateral automatisms (with the seizure focus ipsilateral in 80%), and ictal speech preservation (with the seizure focus contralateral to the language-dominant hemisphere in 80%). Versive head rotation occurring head movements occurring at times other than immediately before seizures secondarily generalized. In TLE, several clinical seizure manifestations are useful in lateralizing the seizure focus, although some provide no reliable information. Therefore, ictal semiology can assist in the evaluation of patients for seizure surgery, providing additional information in the lateralization of TLE.

  3. Deep Recurrent Neural Networks for seizure detection and early seizure detection systems

    Energy Technology Data Exchange (ETDEWEB)

    Talathi, S. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-05

    Epilepsy is common neurological diseases, affecting about 0.6-0.8 % of world population. Epileptic patients suffer from chronic unprovoked seizures, which can result in broad spectrum of debilitating medical and social consequences. Since seizures, in general, occur infrequently and are unpredictable, automated seizure detection systems are recommended to screen for seizures during long-term electroencephalogram (EEG) recordings. In addition, systems for early seizure detection can lead to the development of new types of intervention systems that are designed to control or shorten the duration of seizure events. In this article, we investigate the utility of recurrent neural networks (RNNs) in designing seizure detection and early seizure detection systems. We propose a deep learning framework via the use of Gated Recurrent Unit (GRU) RNNs for seizure detection. We use publicly available data in order to evaluate our method and demonstrate very promising evaluation results with overall accuracy close to 100 %. We also systematically investigate the application of our method for early seizure warning systems. Our method can detect about 98% of seizure events within the first 5 seconds of the overall epileptic seizure duration.

  4. Combined Effects of Feedforward Inhibition and Excitation in Thalamocortical Circuit on the Transitions of Epileptic Seizures

    Science.gov (United States)

    Fan, Denggui; Duan, Lixia; Wang, Qian; Luan, Guoming

    2017-01-01

    The mechanisms underlying electrophysiologically observed two-way transitions between absence and tonic-clonic epileptic seizures in cerebral cortex remain unknown. The interplay within thalamocortical network is believed to give rise to these epileptic multiple modes of activity and transitions between them. In particular, it is thought that in some areas of cortex there exists feedforward inhibition from specific relay nucleus of thalamus (TC) to inhibitory neuronal population (IN) which has even more stronger functions on cortical activities than the known feedforward excitation from TC to excitatory neuronal population (EX). Inspired by this, we proposed a modified computational model by introducing feedforward inhibitory connectivity within thalamocortical circuit, to systematically investigate the combined effects of feedforward inhibition and excitation on transitions of epileptic seizures. We first found that the feedforward excitation can induce the transition from tonic oscillation to spike and wave discharges (SWD) in cortex, i.e., the epileptic tonic-absence seizures, with the fixed weak feedforward inhibition. Thereinto, the phase of absence seizures corresponding to strong feedforward excitation can be further transformed into the clonic oscillations with the increasing of feedforward inhibition, representing the epileptic absence-clonic seizures. We also observed the other fascinating dynamical states, such as periodic 2/3/4-spike and wave discharges, reversed SWD and clonic oscillations, as well as saturated firings. More importantly, we can identify the stable parameter regions representing the tonic-clonic oscillations and SWD discharges of epileptic seizures on the 2-D plane composed of feedforward inhibition and excitation, where the physiologically plausible transition pathways between tonic-clonic and absence seizures can be figured out. These results indicate the functional role of feedforward pathways in controlling epileptic seizures and

  5. Combined Effects of Feedforward Inhibition and Excitation in Thalamocortical Circuit on the Transitions of Epileptic Seizures

    Directory of Open Access Journals (Sweden)

    Denggui Fan

    2017-07-01

    Full Text Available The mechanisms underlying electrophysiologically observed two-way transitions between absence and tonic-clonic epileptic seizures in cerebral cortex remain unknown. The interplay within thalamocortical network is believed to give rise to these epileptic multiple modes of activity and transitions between them. In particular, it is thought that in some areas of cortex there exists feedforward inhibition from specific relay nucleus of thalamus (TC to inhibitory neuronal population (IN which has even more stronger functions on cortical activities than the known feedforward excitation from TC to excitatory neuronal population (EX. Inspired by this, we proposed a modified computational model by introducing feedforward inhibitory connectivity within thalamocortical circuit, to systematically investigate the combined effects of feedforward inhibition and excitation on transitions of epileptic seizures. We first found that the feedforward excitation can induce the transition from tonic oscillation to spike and wave discharges (SWD in cortex, i.e., the epileptic tonic-absence seizures, with the fixed weak feedforward inhibition. Thereinto, the phase of absence seizures corresponding to strong feedforward excitation can be further transformed into the clonic oscillations with the increasing of feedforward inhibition, representing the epileptic absence-clonic seizures. We also observed the other fascinating dynamical states, such as periodic 2/3/4-spike and wave discharges, reversed SWD and clonic oscillations, as well as saturated firings. More importantly, we can identify the stable parameter regions representing the tonic-clonic oscillations and SWD discharges of epileptic seizures on the 2-D plane composed of feedforward inhibition and excitation, where the physiologically plausible transition pathways between tonic-clonic and absence seizures can be figured out. These results indicate the functional role of feedforward pathways in controlling epileptic

  6. Impact of assimilation window length on diurnal features in a Mars atmospheric analysis

    Directory of Open Access Journals (Sweden)

    Yongjing Zhao

    2015-05-01

    Full Text Available Effective simulation of diurnal variability is an important aspect of many geophysical data assimilation systems. For the Martian atmosphere, thermal tides are particularly prominent and contribute much to the Martian atmospheric circulation, dynamics and dust transport. To study the Mars diurnal variability and Mars thermal tides, the Geophysical Fluid Dynamics Laboratory Mars Global Climate Model with the 4D-local ensemble transform Kalman filter (4D-LETKF is used to perform an analysis assimilating spacecraft temperature retrievals. We find that the use of a ‘traditional’ 6-hr assimilation cycle induces spurious forcing of a resonantly enhanced semi-diurnal Kelvin waves represented in both surface pressure and mid-level temperature by forming a wave 4 pattern in the diurnal averaged analysis increment that acts as a ‘topographic’ stationary forcing. Different assimilation window lengths in the 4D-LETKF are introduced to remove the artificially induced resonance. It is found that short assimilation window lengths not only remove the spurious resonance, but also push the migrating semi-diurnal temperature variation at 50 Pa closer to the estimated ‘true’ tides even in the absence of a radiatively active water ice cloud parameterisation. In order to compare the performance of different assimilation window lengths, short-term to mid-range forecasts based on the hour 00 and 12 assimilation are evaluated and compared. Results show that during Northern Hemisphere summer, it is not the assimilation window length, but the radiatively active water ice clouds that influence the model prediction. A ‘diurnal bias correction’ that includes bias correction fields dependent on the local time is shown to effectively reduce the forecast root mean square differences between forecasts and observations, compensate for the absence of water ice cloud parameterisation and enhance Martian atmosphere prediction. The implications of these results for

  7. Seizures

    Science.gov (United States)

    ... collapse, shake uncontrollably, or even just stare into space. All of these are brief disturbances in brain ... Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

  8. De novo psychogenic seizures after epilepsy surgery: case report

    Directory of Open Access Journals (Sweden)

    MONTENEGRO MARIA AUGUSTA

    2000-01-01

    Full Text Available The occurrence of de novo psychogenic seizures after epilepsy surgery is rare, and is estimated in 1.8% to 3.6%. Seizures after epilepsy surgery should be carefully evaluated, and de novo psychogenic seizures should be considered especially when there is a change in the ictal semiology. We report a patient with de novo psychogenic seizures after anterior temporal lobe removal for refractory temporal lobe epilepsy. Once psychogenic seizures were diagnosed and psychiatric treatment was started, seizures stopped.

  9. Complex partial seizures: cerebellar metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Theodore, W.H.; Fishbein, D.; Deitz, M.; Baldwin, P.

    1987-07-01

    We used positron emission tomography (PET) with (/sup 18/F)2-deoxyglucose to study cerebellar glucose metabolism (LCMRglu) and the effect of phenytoin (PHT) in 42 patients with complex partial seizures (CPS), and 12 normal controls. Mean +/- SD patient LCMRglu was 6.9 +/- 1.8 mg glucose/100 g/min (left = right), significantly lower than control values of 8.5 +/- 1.8 (left, p less than 0.006), and 8.3 +/- 1.6 (right, p less than 0.02). Only four patients had cerebellar atrophy on CT/MRI; cerebellar LCMRglu in these was 5.5 +/- 1.5 (p = 0.054 vs. total patient sample). Patients with unilateral temporal hypometabolism or EEG foci did not have lateralized cerebellar hypometabolism. Patients receiving phenytoin (PHT) at the time of scan and patients with less than 5 years total PHT exposure had lower LCMRglu, but the differences were not significant. There were weak inverse correlations between PHT level and cerebellar LCMRglu in patients receiving PHT (r = -0.36; 0.05 less than p less than 0.1), as well as between length of illness and LCMRglu (r = -0.22; 0.05 less than p less than 0.1). Patients with complex partial seizures have cerebellar hypometabolism that is bilateral and due only in part to the effect of PHT.

  10. Assimilation of SMOS Retrievals in the Land Information System

    Science.gov (United States)

    Blankenship, Clay B.; Case, Jonathan L.; Zavodsky, Bradley T.; Crosson, William L.

    2016-01-01

    The Soil Moisture and Ocean Salinity (SMOS) satellite provides retrievals of soil moisture in the upper 5 cm with a 30-50 km resolution and a mission accuracy requirement of 0.04 cm(sub 3 cm(sub -3). These observations can be used to improve land surface model soil moisture states through data assimilation. In this paper, SMOS soil moisture retrievals are assimilated into the Noah land surface model via an Ensemble Kalman Filter within the NASA Land Information System. Bias correction is implemented using Cumulative Distribution Function (CDF) matching, with points aggregated by either land cover or soil type to reduce sampling error in generating the CDFs. An experiment was run for the warm season of 2011 to test SMOS data assimilation and to compare assimilation methods. Verification of soil moisture analyses in the 0-10 cm upper layer and root zone (0-1 m) was conducted using in situ measurements from several observing networks in the central and southeastern United States. This experiment showed that SMOS data assimilation significantly increased the anomaly correlation of Noah soil moisture with station measurements from 0.45 to 0.57 in the 0-10 cm layer. Time series at specific stations demonstrate the ability of SMOS DA to increase the dynamic range of soil moisture in a manner consistent with station measurements. Among the bias correction methods, the correction based on soil type performed best at bias reduction but also reduced correlations. The vegetation-based correction did not produce any significant differences compared to using a simple uniform correction curve.

  11. Personalized glucose forecasting for type 2 diabetes using data assimilation.

    Science.gov (United States)

    Albers, David J; Levine, Matthew; Gluckman, Bruce; Ginsberg, Henry; Hripcsak, George; Mamykina, Lena

    2017-04-01

    Type 2 diabetes leads to premature death and reduced quality of life for 8% of Americans. Nutrition management is critical to maintaining glycemic control, yet it is difficult to achieve due to the high individual differences in glycemic response to nutrition. Anticipating glycemic impact of different meals can be challenging not only for individuals with diabetes, but also for expert diabetes educators. Personalized computational models that can accurately forecast an impact of a given meal on an individual's blood glucose levels can serve as the engine for a new generation of decision support tools for individuals with diabetes. However, to be useful in practice, these computational engines need to generate accurate forecasts based on limited datasets consistent with typical self-monitoring practices of individuals with type 2 diabetes. This paper uses three forecasting machines: (i) data assimilation, a technique borrowed from atmospheric physics and engineering that uses Bayesian modeling to infuse data with human knowledge represented in a mechanistic model, to generate real-time, personalized, adaptable glucose forecasts; (ii) model averaging of data assimilation output; and (iii) dynamical Gaussian process model regression. The proposed data assimilation machine, the primary focus of the paper, uses a modified dual unscented Kalman filter to estimate states and parameters, personalizing the mechanistic models. Model selection is used to make a personalized model selection for the individual and their measurement characteristics. The data assimilation forecasts are empirically evaluated against actual postprandial glucose measurements captured by individuals with type 2 diabetes, and against predictions generated by experienced diabetes educators after reviewing a set of historical nutritional records and glucose measurements for the same individual. The evaluation suggests that the data assimilation forecasts compare well with specific glucose measurements

  12. Assimilation of diazotrophic nitrogen into pelagic food webs.

    Science.gov (United States)

    Woodland, Ryan J; Holland, Daryl P; Beardall, John; Smith, Jonathan; Scicluna, Todd; Cook, Perran L M

    2013-01-01

    The fate of diazotrophic nitrogen (N(D)) fixed by planktonic cyanobacteria in pelagic food webs remains unresolved, particularly for toxic cyanophytes that are selectively avoided by most herbivorous zooplankton. Current theory suggests that N(D) fixed during cyanobacterial blooms can enter planktonic food webs contemporaneously with peak bloom biomass via direct grazing of zooplankton on cyanobacteria or via the uptake of bioavailable N(D) (exuded from viable cyanobacterial cells) by palatable phytoplankton or microbial consortia. Alternatively, N(D) can enter planktonic food webs post-bloom following the remineralization of bloom detritus. Although the relative contribution of these processes to planktonic nutrient cycles is unknown, we hypothesized that assimilation of bioavailable N(D) (e.g., nitrate, ammonium) by palatable phytoplankton and subsequent grazing by zooplankton (either during or after the cyanobacterial bloom) would be the primary pathway by which N(D) was incorporated into the planktonic food web. Instead, in situ stable isotope measurements and grazing experiments clearly documented that the assimilation of N(D) by zooplankton outpaced assimilation by palatable phytoplankton during a bloom of toxic Nodularia spumigena Mertens. We identified two distinct temporal phases in the trophic transfer of N(D) from N. spumigena to the plankton community. The first phase was a highly dynamic transfer of N(D) to zooplankton with rates that covaried with bloom biomass while bypassing other phytoplankton taxa; a trophic transfer that we infer was routed through bloom-associated bacteria. The second phase was a slowly accelerating assimilation of the dissolved-N(D) pool by phytoplankton that was decoupled from contemporaneous variability in N. spumigena concentrations. These findings provide empirical evidence that N(D) can be assimilated and transferred rapidly throughout natural plankton communities and yield insights into the specific processes underlying

  13. Can developmental venous anomalies cause seizures?

    Science.gov (United States)

    Dussaule, Claire; Masnou, Pascal; Nasser, Ghaïdaa; Archambaud, Frédérique; Cauquil-Michon, Cécile; Gagnepain, Jean-Paul; Bouilleret, Viviane; Denier, Christian

    2017-12-01

    Developmental venous anomalies (DVAs) are congenital anatomical variants of normal venous drainage of normal brain. Although DVAs are often discovered on the occasion of a seizure, their involvement in epilepsy is poorly studied. Our objective was to determine whether DVA can cause seizures, in the cases where there is no associated lesion, including no cavernoma or dysplasia. Based on clinical history, cerebral MRI, EEG recording, and 18 F-FDG PET, we report 4 patients with DVA revealed by seizures. The first patient had a convulsive seizure caused by a hemorrhagic infarction due to thrombosis of her DVA. The second patient had a left temporo-parietal DVA next to a nonspecific lesion, possibly a sequelae of a venous infarction. The last two patients disclosed an isolated and uncomplicated DVA with a concordant epileptic focus confirmed on ictal video EEG recording. We reviewed literature and identified 21 other published cases of seizures caused by complications of a DVA and 9 patients that may have a direct link between epilepsy and an isolated and uncomplicated DVA. Seizures are linked to a DVA in two main situations: presence of an associated epileptogenic lesion, such as cavernoma or dysplasia, and occurrence of a complication of the DVA. Before concluding that a seizure is caused by a DVA, it is essential to perform full MRI protocols to search them. It remains rare and uncertain that isolated and uncomplicated DVA can cause seizures. In this last situation, physiopathological processes are probably different in each patient.

  14. 43 CFR 3.16 - Seizure.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Seizure. 3.16 Section 3.16 Public Lands: Interior Office of the Secretary of the Interior PRESERVATION OF AMERICAN ANTIQUITIES § 3.16 Seizure. Any object of antiquity taken, or collection made, on lands owned or controlled by the United States, without...

  15. Mental Retardation, Mental Illness, and Seizure Diagnosis.

    Science.gov (United States)

    Pary, Robert

    1993-01-01

    Review of psychiatric hospital discharge summaries for 247 individuals with mental retardation and psychiatric disorders found that 39 had a seizure diagnosis. The only difference between the groups with and without seizures was level of mental retardation. No differences existed concerning length of stay, transfer to state hospital, psychiatric…

  16. Orgasm Induced Seizures: A Rare Phenomenon

    African Journals Online (AJOL)

    Introduction. Reflex seizures are well known entities developing in response to a discrete or specific stimulus. Reflex seizures are the ones that “Objectively and consistently are demonstrated to be evoked by a specific afferent stimulus or by the activity of the patient. Afferent stimuli can be: Elementary, that is, unstructured ( ...

  17. Seizure-Alerting Dogs in Epilepsy Management

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-08-01

    Full Text Available Families of all children (1 to 18 years old followed at the Refractory Epilepsy Clinic, Alberta Children’s Hospital, Canada, were surveyed and those who had a dog for at least one year while having at least 1 seizure/month were selected and questioned regarding seizure-related behaviors.

  18. Seizure-Alerting Dogs in Epilepsy Management

    OpenAIRE

    J Gordon Millichap

    2004-01-01

    Families of all children (1 to 18 years old) followed at the Refractory Epilepsy Clinic, Alberta Children’s Hospital, Canada, were surveyed and those who had a dog for at least one year while having at least 1 seizure/month were selected and questioned regarding seizure-related behaviors.

  19. Seizure complicating interscalene brachail plexus block | Idehen ...

    African Journals Online (AJOL)

    We describe a case of seizure occurring immediately after completion of interscalene brachial plexus block, using 20mls mixture of 10mls of 0.5% bupivacaine and 10mls of 2% lidocaine with adrenaline for post operative analgesia. Seizure occurred despite negative test aspiration and non response to the use of 0.5mls of ...

  20. New-onset Seizures in Pediatric Emergency

    Directory of Open Access Journals (Sweden)

    Chun-Yu Chen

    2010-04-01

    Conclusion: Primary care pediatricians should evaluate children presenting to the ED with a first seizure for age, coexistence of fever, seizure type, associated symptoms and history of head injury. We suggest that electrolytes, blood sugar and emergent brain imaging studies should be arranged based on detailed history-taking and thorough physical examinations, but should not be performed routinely.

  1. Effect of Seizure Clustering on Epilepsy Outcome

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-05-01

    Full Text Available A prospective, long-term population-based study was performed to determine whether seizure clustering (3 or more afebrile seizures during a 24 hour period is associated with drug resistance and increased mortality in childhood-onset epilepsy, in a study at University of Turku, Finland, and the Epilepsy Research Group, Berlin, Germany.

  2. Protection against generalised seizured by Dalbergia saxatilis ...

    African Journals Online (AJOL)

    ... provide protection against generalized absence and partial seizures, which further justifies its use in the management of epilepsies and convulsions in traditional African medicine. Keywords: Dalbergia saxatilis, generalized seizure, pentylenetetrazole, kindling, electro- foot shock. West African Joural of Pharmacology and ...

  3. Seizure phenotypes, periodicity, and sleep-wake pattern of seizures in Kcna-1 null mice.

    Science.gov (United States)

    Wright, Samantha; Wallace, Eli; Hwang, Youngdeok; Maganti, Rama

    2016-02-01

    This study was undertaken to describe seizure phenotypes, natural progression, sleep-wake patterns, as well as periodicity of seizures in Kcna-1 null mutant mice. These mice were implanted with epidural electroencephalography (EEG) and electromyography (EMG) electrodes, and simultaneous video-EEG recordings were obtained while animals were individually housed under either diurnal (LD) condition or constant darkness (DD) over ten days of recording. The video-EEG data were analyzed to identify electrographic and behavioral phenotypes and natural progression and to examine the periodicity of seizures. Sleep-wake patterns were analyzed to understand the distribution and onset of seizures across the sleep-wake cycle. Four electrographically and behaviorally distinct seizure types were observed. Regardless of lighting condition that animals were housed in, Kcna-1 null mice initially expressed only a few of the most severe seizure types that progressively increased in frequency and decreased in seizure severity. In addition, a circadian periodicity was noted, with seizures peaking in the first 12h of the Zeitgeber time (ZT) cycle, regardless of lighting conditions. Interestingly, seizure onset differed between lighting conditions where more seizures arose out of sleep in LD conditions, whereas under DD conditions, the majority occurred out of the wakeful state. We suggest that this model be used to understand the circadian pattern of seizures as well as the pathophysiological implications of sleep and circadian disturbances in limbic epilepsies. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. The Role of Seizure-Related SEZ6 as a Susceptibility Gene in Febrile Seizures

    Directory of Open Access Journals (Sweden)

    John C. Mulley

    2011-01-01

    Full Text Available Sixty cases of febrile seizures from a Chinese cohort had previously been reported with a strong association between variants in the seizure-related (SEZ 6 gene and febrile seizures. They found a striking lack of genetic variation in their controls. We found genetic variation in SEZ6 at similar levels at the same DNA sequence positions in our 94 febrile seizure cases as in our 96 unaffected controls. Two of our febrile seizure cases carried rare variants predicted to have damaging consequences. Combined with some of the variants from the Chinese cohort, these data are compatible with a role for SEZ6 as a susceptibility gene for febrile seizures. However, the polygenic determinants underlying most cases of febrile seizures with complex inheritance remain to be determined.

  5. Do recurrent seizure-related head injuries affect seizures in people with epilepsy?

    Science.gov (United States)

    Friedman, David E; Chiang, Sharon; Tobias, Ronnie S

    2012-02-01

    Seizure-related head injuries (SRHIs) are among the most commonly encountered injuries in people with epilepsy (PWE). Whether head injury has an effect on preexisting epilepsy is not known. The purpose of this study was to systematically assess for any possible effects of SRHIs on seizure frequency and seizure semiology over a 2-year period. We identified 204 patients who have been followed at the Baylor Comprehensive Epilepsy Center from 2008 to 2010. SRHI occurred in 18.1% of the cohort. Most injuries (91%) were classified as mild. Though seizure frequency varied following head injury, overall seizure frequency was not significantly impacted by presence or absence of SRHI over the 2-year study period. Changes in seizure semiology were not observed in those with SRHIs. Although mild SRHI is common among PWE, it does not appear to have an effect on seizure characteristics over a relatively short period. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Do recurrent seizure-related head injuries affect seizures in people with epilepsy?

    Science.gov (United States)

    Friedman, David E.; Chiang, Sharon; Tobias, Ronnie S.

    2015-01-01

    Seizure-related head injuries (SRHIs) are among the most commonly encountered injuries in people with epilepsy (PWE). Whether head injury has an effect on preexisting epilepsy is not known. The purpose of this study was to systematically assess for any possible effects of SRHIs on seizure frequency and seizure semiology over a 2-year period. We identified 204 patients who have been followed at the Baylor Comprehensive Epilepsy Center from 2008 to 2010. SRHI occurred in 18.1% of the cohort. Most injuries (91%) were classified as mild. Though seizure frequency varied following head injury, overall seizure frequency was not significantly impacted by presence or absence of SRHI over the 2-year study period. Changes in seizure semiology were not observed in those with SRHIs. Although mild SRHI is common among PWE, it does not appear to have an effect on seizure characteristics over a relatively short period. PMID:22227592

  7. Acute disc prolapse secondary to seizure.

    Science.gov (United States)

    Satia, Imran; Goodwin, Lynsey; Madi, Salem; Hamdalla, Hisham

    2011-06-09

    A 37-year-old female presented following a witnessed generalised tonic clonic seizure while washing her car. Witnesses reported the patient hit her head on the car bumper upon falling. She was investigated for a cause of a second seizure with blood tests, CT and MR brain which were normal. On day 3 of her admission she was still unable to walk since the seizure and a neurological examination was performed which revealed signs consistent with a cervical myelopathy. A cervical MRI scan revealed a disc prolapse with cord compression at C5/6. This was successfully operated and the patient made a good recovery. Given that many of our medical assessment units and emergency department frequently assess patient with seizures, there was an important lesson for us to be more aware of the consequences as well as the cause of seizures.

  8. Seizure detection algorithms based on EMG signals

    DEFF Research Database (Denmark)

    Conradsen, Isa

    Background: the currently used non-invasive seizure detection methods are not reliable. Muscle fibers are directly connected to the nerves, whereby electric signals are generated during activity. Therefore, an alarm system on electromyography (EMG) signals is a theoretical possibility. Objective......: to show whether medical signal processing of EMG data is feasible for detection of epileptic seizures. Methods: EMG signals during generalised seizures were recorded from 3 patients (with 20 seizures in total). Two possible medical signal processing algorithms were tested. The first algorithm was based...... the frequency-based algorithm was efficient for detecting the seizures in the third patient. Conclusion: Our results suggest that EMG signals could be used to develop an automatic seizuredetection system. However, different patients might require different types of algorithms /approaches....

  9. Seizure-induced disinhibition of the HPA axis increases seizure susceptibility.

    Science.gov (United States)

    O'Toole, Kate K; Hooper, Andrew; Wakefield, Seth; Maguire, Jamie

    2014-01-01

    Stress is the most commonly reported precipitating factor for seizures. The proconvulsant actions of stress hormones are thought to mediate the effects of stress on seizure susceptibility. Interestingly, epileptic patients have increased basal levels of stress hormones, including corticotropin-releasing hormone (CRH) and corticosterone, which are further increased following seizures. Given the proconvulsant actions of stress hormones, we proposed that seizure-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis may contribute to future seizure susceptibility. Consistent with this hypothesis, our data demonstrate that pharmacological induction of seizures in mice with kainic acid or pilocarpine increases circulating levels of the stress hormone, corticosterone, and exogenous corticosterone administration is sufficient to increase seizure susceptibility. However, the mechanism(s) whereby seizures activate the HPA axis remain unknown. Here we demonstrate that seizure-induced activation of the HPA axis involves compromised GABAergic control of CRH neurons, which govern HPA axis function. Following seizure activity, there is a collapse of the chloride gradient due to changes in NKCC1 and KCC2 expression, resulting in reduced amplitude of sIPSPs and even depolarizing effects of GABA on CRH neurons. Seizure-induced activation of the HPA axis results in future seizure susceptibility which can be blocked by treatment with an NKCC1 inhibitor, bumetanide, or blocking the CRH signaling with Antalarmin. These data suggest that compromised GABAergic control of CRH neurons following an initial seizure event may cause hyperexcitability of the HPA axis and increase future seizure susceptibility. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Scale invariance properties of intracerebral EEG improve seizure prediction in mesial temporal lobe epilepsy.

    Directory of Open Access Journals (Sweden)

    Kais Gadhoumi

    Full Text Available Although treatment for epilepsy is available and effective for nearly 70 percent of patients, many remain in need of new therapeutic approaches. Predicting the impending seizures in these patients could significantly enhance their quality of life if the prediction performance is clinically practical. In this study, we investigate the improvement of the performance of a seizure prediction algorithm in 17 patients with mesial temporal lobe epilepsy by means of a novel measure. Scale-free dynamics of the intracerebral EEG are quantified through robust estimates of the scaling exponents--the first cumulants--derived from a wavelet leader and bootstrap based multifractal analysis. The cumulants are investigated for the discriminability between preictal and interictal epochs. The performance of our recently published patient-specific seizure prediction algorithm is then out-of-sample tested on long-lasting data using combinations of cumulants and state similarity measures previously introduced. By using the first cumulant in combination with state similarity measures, up to 13 of 17 patients had seizures predicted above chance with clinically practical levels of sensitivity (80.5% and specificity (25.1% of total time under warning for prediction horizons above 25 min. These results indicate that the scale-free dynamics of the preictal state are different from those of the interictal state. Quantifiers of these dynamics may carry a predictive power that can be used to improve seizure prediction performance.

  11. Using Data Assimilation Methods of Prediction of Solar Activity

    Science.gov (United States)

    Kitiashvili, Irina N.; Collins, Nancy S.

    2017-01-01

    The variable solar magnetic activity known as the 11-year solar cycle has the longest history of solar observations. These cycles dramatically affect conditions in the heliosphere and the Earth's space environment. Our current understanding of the physical processes that make up global solar dynamics and the dynamo that generates the magnetic fields is sketchy, resulting in unrealistic descriptions in theoretical and numerical models of the solar cycles. The absence of long-term observations of solar interior dynamics and photospheric magnetic fields hinders development of accurate dynamo models and their calibration. In such situations, mathematical data assimilation methods provide an optimal approach for combining the available observational data and their uncertainties with theoretical models in order to estimate the state of the solar dynamo and predict future cycles. In this presentation, we will discuss the implementation and performance of an Ensemble Kalman Filter data assimilation method based on the Parker migratory dynamo model, complemented by the equation of magnetic helicity conservation and long-term sunspot data series. This approach has allowed us to reproduce the general properties of solar cycles and has already demonstrated a good predictive capability for the current cycle, 24. We will discuss further development of this approach, which includes a more sophisticated dynamo model, synoptic magnetogram data, and employs the DART Data Assimilation Research Testbed.

  12. Compensation for Complete Assimilation in Speech Perception: The Case of Korean Labial-to-Velar Assimilation

    Science.gov (United States)

    Mitterer, Holger; Kim, Sahyang; Cho, Taehong

    2013-01-01

    In connected speech, phonological assimilation to neighboring words can lead to pronunciation variants (e.g., "garden bench" [arrow right] "garde'm' bench"). A large body of literature suggests that listeners use the phonetic context to reconstruct the intended word for assimilation types that often lead to incomplete assimilations (e.g., a…

  13. Data Assimilation - Advances and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brian J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-30

    This presentation provides an overview of data assimilation (model calibration) for complex computer experiments. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Utilization of surrogate models and empirical adjustment for model form error in code calibration form the basis for the statistical methodology considered. The role of probabilistic code calibration in supporting code validation is discussed. Incorporation of model form uncertainty in rigorous uncertainty quantification (UQ) analyses is also addressed. Design criteria used within a batch sequential design algorithm are introduced for efficiently achieving predictive maturity and improved code calibration. Predictive maturity refers to obtaining stable predictive inference with calibrated computer codes. These approaches allow for augmentation of initial experiment designs for collecting new physical data. A standard framework for data assimilation is presented and techniques for updating the posterior distribution of the state variables based on particle filtering and the ensemble Kalman filter are introduced.

  14. Randomized, controlled trial of ibuprofen syrup administered during febrile illnesses to prevent febrile seizure recurrences

    NARCIS (Netherlands)

    M. van Stuijvenberg (Margriet); G. Derksen-Lubsen (Gerarda); E.W. Steyerberg (Ewout); J.D.F. Habbema (Dik); H.A. Moll (Henriëtte)

    1998-01-01

    textabstractOBJECTIVES: Febrile seizures recur frequently. Factors increasing the risk of febrile seizure recurrence include young age at onset, family history of febrile seizures, previous recurrent febrile seizures, time lapse since previous seizure <6 months,

  15. Data Assimilation by Conditioning of Driving Noise on Future Observations

    KAUST Repository

    Lee, Wonjung

    2014-08-01

    Conventional recursive filtering approaches, designed for quantifying the state of an evolving stochastic dynamical system with intermittent observations, use a sequence of i) an uncertainty propagation step followed by ii) a step where the associated data is assimilated using Bayes\\' rule. Alternatively, the order of the steps can be switched to i) one step ahead data assimilation followed by ii) uncertainty propagation. In this paper, we apply this smoothing-based sequential filter to systems driven by random noise, however with the conditioning on future observation not only to the system variable but to the driving noise. Our research reveals that, for the nonlinear filtering problem, the conditioned driving noise is biased by a nonzero mean and in turn pushes forward the filtering solution in time closer to the true state when it drives the system. As a result our proposed method can yield a more accurate approximate solution for the state estimation problem. © 1991-2012 IEEE.

  16. Ensemble-Based Data Assimilation in Reservoir Characterization: A Review

    Directory of Open Access Journals (Sweden)

    Seungpil Jung

    2018-02-01

    Full Text Available This paper presents a review of ensemble-based data assimilation for strongly nonlinear problems on the characterization of heterogeneous reservoirs with different production histories. It concentrates on ensemble Kalman filter (EnKF and ensemble smoother (ES as representative frameworks, discusses their pros and cons, and investigates recent progress to overcome their drawbacks. The typical weaknesses of ensemble-based methods are non-Gaussian parameters, improper prior ensembles and finite population size. Three categorized approaches, to mitigate these limitations, are reviewed with recent accomplishments; improvement of Kalman gains, add-on of transformation functions, and independent evaluation of observed data. The data assimilation in heterogeneous reservoirs, applying the improved ensemble methods, is discussed on predicting unknown dynamic data in reservoir characterization.

  17. Clinical seizure lateralization in frontal lobe epilepsy.

    Science.gov (United States)

    Bonelli, Silvia Beatrice; Lurger, Stefanie; Zimprich, Fritz; Stogmann, Elisabeth; Assem-Hilger, Eva; Baumgartner, Christoph

    2007-03-01

    We systematically analyzed the lateralizing value of clinical seizure semiology in patients with frontal lobe epilepsy (FLE). We studied the incidence, positive predictive value (PPV), and the lateralizing significance of various clinical symptoms in 228 seizures (s) of 31 patients (p) with medically refractory FLE (17 with left-sided and 14 with right-sided seizure onset). Seizures recorded during prolonged video-EEG monitoring were assessed by two independent reviewers blinded for the patient's clinical data. Analysis was performed both for patients and seizures. Version [16 p (52%); PPV, 94%; p=0.001; 47 s (21%); PPV, 75%; p=0.001], unilateral clonic movements [16 p (52%); PPV, 81%; p=0.021; 32 s (14%); PPV, 81%; p=0.001], unilateral dystonic posturing [eight p (26%); PPV, 75%; p=0.289; 46 s (20%); PPV, 80%; p=0.001], unilateral tonic posturing [10 p (32%); PPV, 80%; p=0.109; 19 s (7.4%); PPV, 79%; p=0.019], and unilateral grimacing [10 p (32%); PPV, 100%; p=0.002; 19 s (8%); PPV, 100%; p=0.001] were of lateralizing significance, indicating a contralateral seizure onset. Asymmetric ending [five p (16%); PPV, 80%; p=0.375; nine s (4%); PPV, 89%; p=0.039] after secondarily generalized tonic-clonic seizures was significantly associated with an ipsilateral seizure onset. Pure ictal vocalizations occurred significantly more frequently in seizures of right hemispheric onset [13 p (42%); PPV, 62%; p=0.581; 63 s (28%); PPV, 73%; p=0. 001], whereas in individual patients, this symptom showed no lateralizing significance. The remaining clinical symptoms (figure 4 sign, unilateral hand automatisms, early head turning, postictal nose wiping, and unilateral eye blinking) were not of lateralizing significance in our patients. The results of clinical seizure lateralization corresponded with the final lateralization of the seizure-onset zone in 81% of our patients. Clinical seizure semiology can provide correct information on the lateralization of the seizure-onset zone in >80

  18. First seizure definitions and worldwide incidence and mortality.

    Science.gov (United States)

    Hauser, W Allen; Beghi, Ettore

    2008-01-01

    While all patients with epilepsy experience seizures, not all individuals with seizures have epilepsy. Seizures may be acute symptomatic or unprovoked. Acute symptomatic seizures are seizures occurring at the time of a systemic insult or in close temporal association with a documented brain insult. Unprovoked seizures are seizures occurring in the absence of precipitating factors and may be caused by a static injury (remote symptomatic seizures) or a progressing injury (progressive symptomatic seizures). Unprovoked seizures may be single or recurrent (epilepsy). The incidence of acute symptomatic seizures is 29-39 per 100,000 per year. These predominate in men, in the youngest age class, and in the elderly. Traumatic brain injury, cerebrovascular disease, drug withdrawal, infarction, and metabolic insults are the commonest causes. The incidence of single unprovoked seizures is 23-61 per 100,000 person-years. As with epilepsy, single unprovoked seizures predominate in men and in patients less than 12 months and older than 65 years. Studies on the mortality of acute symptomatic seizures are lacking. A standardized mortality ratio (SMR) of 2.3 has been reported in patients experiencing a single unprovoked seizure. The SMR in patients with a newly diagnosed unprovoked seizure ranges from 2.5 to 4.1 according to the study population and design. The SMR is highest in the youngest patients and in those with symptomatic seizures.

  19. Classification of clinical semiology in epileptic seizures in neonates.

    Science.gov (United States)

    Nagarajan, Lakshmi; Palumbo, Linda; Ghosh, Soumya

    2012-03-01

    The clinical semiology of 61 neonatal seizures with EEG correlates, in 24 babies was analysed. Most seizures (89%) had multiple features during the EEG discharge. The seizures were classified using the prominent clinical feature at onset, and all features seen during the seizure, using an extended classification scheme. Orolingual features occurred most frequently at onset (30%), whereas ocular phenomena occurred most often during the seizure (70%). Orolingual, ocular and autonomic features were seen at onset in 55% of the seizures. Seizure onsets with clonic, tonic and hypomotor features were seen in 20%, 8% and 18% respectively. Clinico-electrical correlations were as follows. The EEG discharge involved both hemispheres in 54% of all seizures, in clonic seizures this was 93%. Focal clonic seizures were associated with EEG seizure onset from the contralateral hemisphere. Majority of the clonic and hypomotor seizures had a left hemisphere ictal EEG onset. Orolingual seizures frequently started from the right hemisphere, whereas ocular and autonomic seizures arose from either hemisphere. There was no significant difference in mortality, morbidity, abnormal neuroimaging and EEG background abnormalities in babies with or without clonic seizures. This study provides insights into neuronal networks that underpin electroclinical seizures, by analysing and classifying the obvious initial clinical features and those during the seizure. Copyright © 2011 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  20. Advanced Data Assimilation for Geosciences : Lecture Notes of the Les Houches School of Physics

    CERN Document Server

    Bocquet, Marc; Cosme, Emmanuel; Cugliandolo, Leticia F

    2014-01-01

    This book gathers notes from lectures and seminars given during a three-week school on theoretical and applied data assimilation held in Les Houches in 2012. Data assimilation aims at determining as accurately as possible the state of a dynamical system by combining heterogeneous sources of information in an optimal way. Generally speaking, the mathematical methods of data assimilation describe algorithms for forming optimal combinations of observations of a system, a numerical model that describes its evolution, and appropriate prior information. Data assimilation has a long history of application to high-dimensional geophysical systems dating back to the 1960s, with application to the estimation of initial conditions for weather forecasts. It has become a major component of numerical forecasting systems in geophysics, and an intensive field of research, with numerous additional applications in oceanography and atmospheric chemistry, with extensions to other geophysical sciences. The physical complexity and ...

  1. Analysis of the Martian ozone cycle by assimilation of SPICAM observations

    Science.gov (United States)

    Holmes, J. A.; Lewis, S. R.; Patel, M. R.; Lefèvre, F.

    2013-09-01

    Observations of ozone, a trace gas on Mars, have the potential to constrain atmospheric dynamical and physical processes. Current Mars Global Circulation Models (MGCMs) [1, 2, 3] are able to represent the photochemistry occuring in the atmosphere, with comparisons to observations used to confine particular species. However, a long term comparison using data assimilation provides a more robust constraint on the model. We have assimilated total-ozone observations from SPICAM into an MGCM to study the Martian ozone cycle. Ozone has never before been assimilated for an extraterrestrial planet. Our aim is to use ozone to provide a preliminary technique for trace gas data assimilation for the analysis of observations from current and future satellite missions (such as ExoMars) which observe the spatial and temporal distribution of trace gases on Mars.

  2. The role of branch architecture in assimilate production and partitioning: the example of apple (Malus domestica).

    Science.gov (United States)

    Fanwoua, Julienne; Bairam, Emna; Delaire, Mickael; Buck-Sorlin, Gerhard

    2014-01-01

    Understanding the role of branch architecture in carbon production and allocation is essential to gain more insight into the complex process of assimilate partitioning in fruit trees. This mini review reports on the current knowledge of the role of branch architecture in carbohydrate production and partitioning in apple. The first-order carrier branch of apple illustrates the complexity of branch structure emerging from bud activity events and encountered in many fruit trees. Branch architecture influences carbon production by determining leaf exposure to light and by affecting leaf internal characteristics related to leaf photosynthetic capacity. The dynamics of assimilate partitioning between branch organs depends on the stage of development of sources and sinks. The sink strength of various branch organs and their relative positioning on the branch also affect partitioning. Vascular connections between branch organs determine major pathways for branch assimilate transport. We propose directions for employing a modeling approach to further elucidate the role of branch architecture on assimilate partitioning.

  3. Degree of Postictal Suppression Depends on Seizure Induction Time in Magnetic Seizure Therapy and Electroconvulsive Therapy.

    Science.gov (United States)

    Kayser, Sarah; Bewernick, Bettina H; Soehle, Martin; Switala, Christina; Gippert, Sabrina M; Dreimueller, Nadine; Schlaepfer, Thomas E

    2017-09-01

    Anesthesia is required for both magnetic seizure therapy (MST) and electroconvulsive therapy (ECT), although it has anticonvulsant properties. In this case, bispectral index (BIS) monitoring, a specific electroencephalogram-derived monitoring, can be used to find the optimal seizure induction time during anesthesia to elicit adequate seizures. A measurement of seizure adequacy in electroencephalogram is the postictal suppression. The purpose of this study was to investigate the influence of seizure induction time on the degree of postictal suppression by comparing BIS versus no-BIS monitoring in MST and ECT. Twenty patients with treatment-resistant depression were randomly assigned to either MST or ECT. Each patient underwent 3 treatments with the determination of seizure induction time by defined prestimulation BIS (BIS condition) and 3 treatments with determination of seizure induction time by controlled clinical trial protocol (no-BIS condition). Statistical analysis was calculated by repeated-measures analysis of variance. The degree of postictal suppression was more pronounced in both MST and ECT, with BIS monitoring. In this connection, no differences between MST and ECT were found. Seizure induction time was significantly later in the BIS condition (181.3 ± 6 seconds) compared with the no-BIS condition (114.3 ± 12 seconds) (P < 0.001). Adequacy of seizures, in the form of the degree of postictal suppression, was superior by determining the seizure induction time with BIS in both MST and ECT. Further research is needed to investigate the correlation between the degree of postictal suppression and treatment response.

  4. New onset seizures in HIV--seizure semiology, CD4 counts, and viral loads.

    Science.gov (United States)

    Modi, Mala; Mochan, Andre; Modi, Girish

    2009-05-01

    Thirty-seven HIV-positive patients with new-onset seizures (NOS) were prospectively identified during a 1-year study period. The patients were categorized according to the different mechanisms causing NOS in HIV, namely focal brain lesion (FBL) in 21 patients (57%), meningitis in 6 patients (16%), metabolic derangement (no patient), and no identified cause (NIC) other than HIV itself (10 patients, 27%). Seizure semiology, CD4 counts, and blood and cerebral spinal fluid (CSF) viral loads were studied to identify any special characteristics of the different categories. With respect to seizure semiology, all NIC patients had generalized seizures. Two-thirds of the meningitis patients had generalized seizures with one-third having focal seizures. Half of the patients with FBL had generalized seizures and one-third had focal seizures. Status epilepticus was strongly associated with FBL. No significant difference could be detected between the subgroups with respect to CD4 counts and serum and CSF viral loads. The median CD4 count in all patients was 108 cells/ml, indicating advanced immunosuppression. In the FBL group this was 104 cells/ml. In the meningitis group the median CD4 count was 298 cells/ml, and in the NIC group this was 213 cells/ml. Similarly, no differences were noted in the NOS categories with respect to serum and CSF viral loads. Seizures in HIV are a nonspecific manifestation of the seizure mechanism.

  5. Hyperthyroidism and seizures during pregnancy.

    Science.gov (United States)

    Mayer, D C; Thorp, J; Baucom, D; Spielman, F J

    1995-05-01

    Untreated hyperthyroidism during pregnancy is associated with increased maternal and perinatal morbidity. Some features of this disease simulate preeclampsia, which may encourage delivery of the fetus. We report a case of poorly controlled hyperthyroidism associated with generalized seizures, where patient management was directed at a diagnosis of preeclampsia-eclampsia. Although the presence of eclampsia and marked hyperthyroidism is very rare, this case illustrates the importance of aggressive medical management of hyperthyroidism. A 17-year-old gravida was diagnosed with hyperthyroidism at 15 weeks' gestation. At 26 weeks' gestation, she was admitted to the hospital after noting edema of the upper and lower extremities, nausea, vomiting, shortness of breath, and a cough. At admission, she was hypertensive, tachycardic, and dyspneic. The patient was believed to have preeclampsia with pulmonary edema complicated by hyperthyroidism. We initiated magnesium sulfate therapy and administered several bolus doses of hydralazine, with little effect on blood pressure. Oliguria was noted, and a pulmonary artery catheter was inserted. Hours later, generalized seizure activity occurred, and a decision was made for abdominal delivery. Postoperatively, cardiovascular function stabilized. On postoperative day 3, we received the results of the thyroid function tests obtained at admission, which suggested a markedly hyperthyroid condition. Untreated or poorly treated hyperthyroidism may present a clinical picture similar to preeclampsia. In our case, both disease processes coexisted in their severest forms. It is possible, although completely unproven, that a relationship exists between poorly controlled hyperthyroidism and preeclampsia-eclampsia. More importantly, accurate diagnosis of hyperthyroidism should lead to prompt medical or surgical management, thereby decreasing maternal and perinatal morbidity.

  6. Nonepileptic Seizures: An Updated Review

    Science.gov (United States)

    Perez, David L.; LaFrance, W. Curt

    2016-01-01

    Psychogenic nonepileptic seizures are a Functional Neurological Disorder/ Conversion Disorder subtype, which are neurobehavioral conditions at the interface of Neurology and Psychiatry. Significant advancements over the past decade have been made in the diagnosis, management and neurobiological understanding of PNES. This article reviews published PNES research focusing on semiologic features that distinguish PNES from epileptic seizures, consensus diagnostic criteria, the intersection of PNES and other comorbidities, neurobiological studies, evidence-based treatment interventions and outcome studies. Epidemiology and health care utilization studies highlight a continued unmet medical need in the comprehensive care of PNES. Consensus guidelines for diagnostic certainty are based on clinical history, semiology of witnessed typical event(s), and EEG findings. While certain semiologic features may aid the diagnosis of PNES, the gold standard remains capturing a typical event on video electroencephalography (EEG) showing the absence of epileptiform activity with history and semiology consistent with PNES. Medical-neurologic and psychiatric comorbidities are prevalent in PNES and should be assessed in diagnostic evaluations, and integrated into treatment interventions and prognostic considerations. Several studies, including a pilot multicenter, randomized clinical trial, have now demonstrated that a cognitive behavioral therapy informed psychotherapy is an efficacious treatment for PNES, and additional efforts are necessary to evaluate the utility of pharmacologic and other psychotherapy treatments. Neuroimaging studies, while requiring replication, suggest that PNES may occur in the context of alterations within and across sensorimotor, emotion regulation/processing, cognitive control and multimodal integration brain systems. Future research could investigate similarities and differences between PNES and other somatic symptom disorders. PMID:26996600

  7. Risk of seizure recurrence after a first unprovoked seizure: a prospective study among Jordanian children.

    Science.gov (United States)

    Daoud, A S; Ajloni, S; El-Salem, K; Horani, K; Otoom, S; Daradkeh, T

    2004-03-01

    There is wide variation in the reported recurrence rate after a first unprovoked seizure in children. We investigated the risk of recurrence after a first unprovoked seizure in Jordanian children and the risk factors associated with increased recurrence rate. All consecutive patients aged 3 months-14 years who presented with their first unprovoked seizures between January 1997 and 2000, were included in a prospective study and followed up for 3 years for possible recurrence. Of the patients studied, there was slight male predominance (56.6%) and 55% of them were 2-9 years of age. Generalised seizures were reported in 75% and the remaining 25% had partial seizures. The duration of seizure was 1-4 minutes in 59%. Family history of epilepsy was positive in 31% and parental consanguinity in 32%. The role of these factors in increasing the risk of recurrence was also investigated. Two hundred sixty-five patients were included in the study and continued follow up for 3 years. Ninety-eight (37%) of them experienced seizure recurrence. Among the predictor factors for recurrence, partial seizure (P = 0.003) and positive family history (P = 0.000) were associated with a statistically significant increased risk. Sex, age, duration of seizure and consanguinity were not associated with increased risk of recurrence. Thirty-seven percent of the children studied experienced a second attack after a first unprovoked seizure over the 3 years follows up period. The risk of recurrence was significantly higher in children with a partial seizure (55%) and among those with a positive family history of epilepsy (59%). Age at first seizure, sex, duration of seizure and consanguinity were not significantly related to the risk of recurrence.

  8. The Race Race: Assimilation in America

    Science.gov (United States)

    Balis, Andrea; Aman, Michael

    2013-01-01

    Can race and assimilation be taught? Interdisciplinary pedagogy provides a methodology, context, and use of nontraditional texts culled from American cultural history such as from, theater and historical texts. This approach and these texts prove useful for an examination of race and assimilation in America. The paper describes a course that while…

  9. Do oral contraceptives increase epileptic seizures?

    Science.gov (United States)

    Reddy, Doodipala Samba

    2017-02-01

    Hormonal contraceptives are used by over 100 million people worldwide. Recently, there has been an emerging interest in studying the potential impact of oral contraceptives (OCs) on certain neurological conditions. It has been suspected for some time that hormonal birth control increases seizure activity in women with epilepsy, but there is little supportive data. Areas covered: Literature from PubMed and online sources was analyzed with respect to hormonal contraception and epilepsy or seizures. New evidence indicates that OCs can cause an increase in seizures in women with epilepsy. The epilepsy birth control registry, which surveyed women with epilepsy, found that those using hormonal contraceptives self-reported 4.5 times more seizures than those that did not use such contraceptives. A preclinical study confirmed these outcomes wherein epileptic animals given ethinyl estradiol, the primary component of OCs, had more frequent seizures that are more likely to be resistant. Expert commentary: OC pills may increase seizures in women with epilepsy and such refractory seizures are more likely to cause neuronal damage in the brain. Thus, women of child bearing age with epilepsy should consider using non-hormonal forms of birth control to avoid risks from OC pills. Additional research into the mechanisms and prospective clinical investigation are needed.

  10. Oxaliplatin-Induced Tonic-Clonic Seizures

    Directory of Open Access Journals (Sweden)

    Ahmad K. Rahal

    2015-01-01

    Full Text Available Oxaliplatin is a common chemotherapy drug used for colon and gastric cancers. Common side effects are peripheral neuropathy, hematological toxicity, and allergic reactions. A rare side effect is seizures which are usually associated with posterior reversible leukoencephalopathy syndrome (PRES. A 50-year-old male patient presented with severe abdominal pain. CT scan of the abdomen showed acute appendicitis. Appendectomy was done and pathology showed mixed adenoneuroendocrine carcinoma. Adjuvant chemotherapy was started with Folinic acid, Fluorouracil, and Oxaliplatin (FOLFOX. During the third cycle of FOLFOX, the patient developed tonic-clonic seizures. Laboratory workup was within normal limits. EEG and MRI of the brain showed no acute abnormality. The patient was rechallenged with FOLFOX but he had tonic-clonic seizures for the second time. His chemotherapy regimen was switched to Folinic acid, Fluorouracil, and Irinotecan (FOLFIRI. After 5 cycles of FOLFIRI, the patient did not develop any seizures, making Oxaliplatin the most likely culprit for his seizures. Oxaliplatin-induced seizures rarely occur in the absence of PRES. One case report has been described in the literature. We present a rare case of tonic-clonic seizures in a patient receiving Oxaliplatin in the absence of PRES.

  11. Oxaliplatin-Induced Tonic-Clonic Seizures.

    Science.gov (United States)

    Rahal, Ahmad K; Truong, Phu V; Kallail, K James

    2015-01-01

    Oxaliplatin is a common chemotherapy drug used for colon and gastric cancers. Common side effects are peripheral neuropathy, hematological toxicity, and allergic reactions. A rare side effect is seizures which are usually associated with posterior reversible leukoencephalopathy syndrome (PRES). A 50-year-old male patient presented with severe abdominal pain. CT scan of the abdomen showed acute appendicitis. Appendectomy was done and pathology showed mixed adenoneuroendocrine carcinoma. Adjuvant chemotherapy was started with Folinic acid, Fluorouracil, and Oxaliplatin (FOLFOX). During the third cycle of FOLFOX, the patient developed tonic-clonic seizures. Laboratory workup was within normal limits. EEG and MRI of the brain showed no acute abnormality. The patient was rechallenged with FOLFOX but he had tonic-clonic seizures for the second time. His chemotherapy regimen was switched to Folinic acid, Fluorouracil, and Irinotecan (FOLFIRI). After 5 cycles of FOLFIRI, the patient did not develop any seizures, making Oxaliplatin the most likely culprit for his seizures. Oxaliplatin-induced seizures rarely occur in the absence of PRES. One case report has been described in the literature. We present a rare case of tonic-clonic seizures in a patient receiving Oxaliplatin in the absence of PRES.

  12. Improved neonatal seizure detection using adaptive learning.

    Science.gov (United States)

    Ansari, A H; Cherian, P J; Caicedo, A; De Vos, M; Naulaers, G; Van Huffel, S

    2017-07-01

    In neonatal intensive care units performing continuous EEG monitoring, there is an unmet need for around-the-clock interpretation of EEG, especially for recognizing seizures. In recent years, a few automated seizure detection algorithms have been proposed. However, these are suboptimal in detecting brief-duration seizures (<; 30s), which frequently occur in neonates with severe neurological problems. Recently, a multi-stage neonatal seizure detector, composed of a heuristic and a data-driven classifier was proposed by our group and showed improved detection of brief seizures. In the present work, we propose to add a third stage to the detector in order to use feedback of the Clinical Neurophysiologist and adaptively retune a threshold of the second stage to improve the performance of detection of brief seizures. As a result, the false alarm rate (FAR) of the brief seizure detections decreased by 50% and the positive predictive value (PPV) increased by 18%. At the same time, for all detections, the FAR decreased by 35% and PPV increased by 5% while the good detection rate remained unchanged.

  13. Semiology of the rare seizure subtype piloerection.

    Science.gov (United States)

    Lam, Erek M; Worrell, Gregory A; Laughlin, Ruple S

    2010-12-01

    To report piloerection and vasomotor instability as a sole manifestation of partial seizures. Case report. Inpatient tertiary care center. A 72-year-old man with acute onset of repetitive autonomic events. Extensive cardiovascular evaluation, electroencephalographic testing, radiology, laboratory assessment, and frequency of clinical events (seizures). We characterize an uncommon manifestation of right temporal lobe partial seizures, initially thought to be cardiovascular in origin, as pilomotor seizures accompanied by other autonomic phenomena. The ictal electroencephalogram recordings established the diagnosis of right temporal lobe seizures, and head magnetic resonance imaging demonstrated right mesial temporal T2 signal change, enhancement, and subsequent atrophy. The underlying etiology was not uncovered despite an extensive laboratory and radiological evaluation. However, given the history and imaging findings, an infectious or secondary immunological etiology was suspected. Pilomotor events with other transient autonomic features, such as tachycardia and blood pressure fluctuations, may represent localization-related epilepsy. The acute onset of these events accompanied by other autonomic phenomena in the setting of focal magnetic resonance imaging abnormalities within the hippocampal region raises questions concerning pilomotor seizures as well as the differential diagnosis of acute seizure activity in the setting of neuroimaging findings characteristic for limbic encephalitis.

  14. Epileptic seizure after treatment with thiocolchicoside

    Directory of Open Access Journals (Sweden)

    Pedro Giavina-Bianchi

    2009-08-01

    Full Text Available Pedro Giavina-Bianchi1,2, Mara Giavina-Bianchi1, Luciana Kase Tanno1, Luis Felipe Chiaverini Ensina1, Antôno Abílio Motta1, Jorge Kalil1,21Division of Clinical Immunology and Allergy, University of São Paulo, São Paulo, SP, Brazil; 2Institute of Science, Hospital Alemao Oswaldo CruzBackground: Adverse drug reactions are important determinants of inpatient and outpatient morbidity. Thiocolchicoside is a semisynthetic derivate of naturally occurring colchicoside, which is largely used in humans as a centrally acting muscle relaxant. Epileptic seizures after thiocolchicoside intake have been reported in individuals with a history of epilepsy, acute brain injury or possible blood–brain barrier disruption.Case report: We report the case of a 66-year-old male patient presenting a sudden epileptic seizure temporally related to the intake of thiocolchicoside for muscle contracture and pain. The probably causes of the seizures were thiocolchicoside intake and cerebral microhemorrhages attributed to cerebral amyloid angiopathy.Discussion: Drugs only rarely cause focal seizures. Our case indicates that thiocolchicoside can precipitate seizures in predisposed patients, and that its use should be avoided in patients with brain diseases (and therefore lower seizure thresholds or blood–brain barrier disruption. This information should be provided in the drug package insert.Keywords: adverse drug reaction, thiocolchicoside, coltrax, epileptic seizure, muscle relaxant, cerebral amyloid angiopathy

  15. Biotelemetry system for Epilepsy Seizure Control

    Energy Technology Data Exchange (ETDEWEB)

    Smith, LaCurtise; Bohnert, George W.

    2009-07-02

    The Biotelemetry System for Epilepsy Seizure Control Project developed and tested an automated telemetry system for use in an epileptic seizure prevention device that precisely controls localized brain temperature. This project was a result of a Department of Energy (DOE) Global Initiatives for Proliferation Prevention (GIPP) grant to the Kansas City Plant (KCP), Argonne National Laboratory (ANL), and Pacific Northwest National Laboratory (PNNL) to partner with Flint Hills Scientific, LLC, Lawrence, KS and Biophysical Laboratory Ltd (BIOFIL), Sarov, Russia to develop a method to help control epileptic seizures.

  16. Ambroxol-induced focal epileptic seizure.

    Science.gov (United States)

    Lapenta, Leonardo; Morano, Alessandra; Fattouch, Jinane; Casciato, Sara; Fanella, Martina; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

    2014-01-01

    It is well known that in epileptic patients some compounds and different drugs used for the treatment of comorbidities can facilitate or provoke seizures, this evidence regarding a wide spectrum of pharmacological categories. The potential facilitating factors usually include direct toxic effects or pharmacological interactions of either active ingredients or excipients. We report the case of a patient with drug-resistant epilepsy who experienced focal epileptic seizures, easily and constantly reproducible, after each administration of a cough syrup. This is, to our knowledge, the first electroencephalogram-documented case of focal epileptic seizures induced by cough syrup containing ambroxol as active ingredient.

  17. [Semiology and propagation of epileptic seizures].

    Science.gov (United States)

    Gellner, A-K; Fritsch, B

    2013-06-01

    The evaluation of episodic seizure-like symptoms is a common challenge in the neurologist's daily routine. The clinical signs (semiology) are the most important puzzle pieces to distinguish epileptic seizures from other episodic entities. Due to the often far-reaching health and social consequences of the diagnosis of epilepsy, the early and rigorous assessment of episodic symptoms by means of the patient history is important. This assessment is based on knowledge of the association of certain semiologies with epileptic syndromes and brain regions; however, certain limitations and pitfalls have to be considered. Typical propagation pathways of seizure activity determine the serial occurrence of semiological features and provide supplementary information.

  18. Acute disc prolapse secondary to seizure

    OpenAIRE

    Satia, Imran; Goodwin, Lynsey; Madi, Salem; Hamdalla, Hisham

    2011-01-01

    A 37-year-old female presented following a witnessed generalised tonic clonic seizure while washing her car. Witnesses reported the patient hit her head on the car bumper upon falling. She was investigated for a cause of a second seizure with blood tests, CT and MR brain which were normal. On day 3 of her admission she was still unable to walk since the seizure and a neurological examination was performed which revealed signs consistent with a cervical myelopathy. A cervical MRI scan revealed...

  19. Are afebrile seizures associated with minor infections a single seizure category? A hospital-based prospective cohort study on outcomes of first afebrile seizure in early childhood.

    Science.gov (United States)

    Zhang, Ting; Ma, Jiannan; Gan, Xiaoming; Xiao, Nong

    2014-07-01

    To explore if afebrile seizures associated with minor infections are a single category of seizure, or a set of different kinds of seizures. We conducted this prospective cohort study on three kinds of first afebrile seizure: first afebrile seizure associated with gastrointestinal infection (AS-GI), first afebrile seizure associated with nongastrointestinal infection (AS-nGI), and first unprovoked seizure (US). The Kaplan-Meier estimate risks of recurrent seizures were analyzed and compared pairwise. The characteristics of recurrent seizures were also compared pairwise. The Kaplan-Meier estimate risks of recurrent seizure at 2 years of the AS-GI, AS-nGI, and US groups were 6.9%, 23.7%, and 37.8%, respectively. The pairwise differences were significant between the AS-GI and US groups (p seizures in patients with recurrence, the pairwise differences were significant between the AS-GI and US groups (p seizures associated with minor infections are indeed of two distinguishable kinds: AS-GI, if free of risk factors such as a family history of epilepsy, had a better prognosis and should be categorized as an acute symptomatic seizure, whereas patients with first AS-nGI, like patients with first US, may have recurrent unprovoked seizures, which suggests this category's essential difference from AS-GI. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  20. Seizure prognosis of patients with low-grade tumors.

    Science.gov (United States)

    Kahlenberg, Cynthia A; Fadul, Camilo E; Roberts, David W; Thadani, Vijay M; Bujarski, Krzysztof A; Scott, Rod C; Jobst, Barbara C

    2012-09-01

    Seizures frequently impact the quality of life of patients with low grade tumors. Management is often based on best clinical judgment. We examined factors that correlate with seizure outcome to optimize seizure management. Patients with supratentorial low-grade tumors evaluated at a single institution were retrospectively reviewed. Using multiple regression analysis the patient characteristics and treatments were correlated with seizure outcome using Engel's classification. Of the 73 patients with low grade tumors and median follow up of 3.8 years (range 1-20 years), 54 (74%) patients had a seizure ever and 46 (63%) had at least one seizure before tumor surgery. The only factor significantly associated with pre-surgical seizures was tumor histology. Of the 54 patients with seizures ever, 25 (46.3%) had a class I outcome at last follow up. There was no difference in seizure outcome between grade II gliomas (astrocytoma grade II, oligodendroglioma grade II, mixed oligo-astrocytoma grade II) and other pathologies (pilocytic astrocytoma, ependymomas, DNET, gangliocytoma and ganglioglioma). Once seizures were established seizure prognosis was similar between different pathologies. Chemotherapy (p=0.03) and radiation therapy (p=0.02) had a positive effect on seizure outcome. No other parameter including significant tumor growth during the follow up period predicted seizure outcome. Only three patients developed new-onset seizures after tumor surgery that were non-perioperative. Anticonvulsant medication was tapered in 14 patients with seizures and 10 had no further seizures. Five patients underwent additional epilepsy surgery with a class I outcome in four. Two patients received a vagal nerve stimulator with >50% seizure reduction. Seizures at presentation are the most important factor associated with continued seizures after tumor surgery. Pathology does not influence seizure outcome. Use of long term prophylactic anticonvulsants is unwarranted. Chemotherapy and

  1. 50 CFR 12.11 - Notification of seizure.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Notification of seizure. 12.11 Section 12... SEIZURE AND FORFEITURE PROCEDURES Preliminary Requirements § 12.11 Notification of seizure. Except where the owner or consignee is personally notified or seizure is made pursuant to a search warrant, the...

  2. 50 CFR 12.5 - Seizure by other agencies.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Seizure by other agencies. 12.5 Section 12... SEIZURE AND FORFEITURE PROCEDURES General Provisions § 12.5 Seizure by other agencies. Any authorized... the laws listed in § 12.2 will, if so requested, deliver such seizure to the appropriate Special Agent...

  3. Seizure variables and cognitive performance in patients with epilepsy

    African Journals Online (AJOL)

    There are scanty reports on the contributions of seizure variables like seizure types, frequency of seizures, duration of epilepsy, age at onset and anti-epileptic drugs to cognitive disturbances in Nigerian Africans. This study assessed the effects of seizure variables on the cognitive performances of patients with epilepsy.

  4. Seizure semiology identifies patients with bilateral temporal lobe epilepsy.

    Science.gov (United States)

    Loesch, Anna Mira; Feddersen, Berend; Tezer, F Irsel; Hartl, Elisabeth; Rémi, Jan; Vollmar, Christian; Noachtar, Soheyl

    2015-01-01

    Laterality in temporal lobe epilepsy is usually defined by EEG and imaging results. We investigated whether the analysis of seizure semiology including lateralizing seizure phenomena identifies bilateral independent temporal lobe seizure onset. We investigated the seizure semiology in 17 patients in whom invasive EEG-video-monitoring documented bilateral temporal seizure onset. The results were compared to 20 left and 20 right consecutive temporal lobe epilepsy (TLE) patients who were seizure free after anterior temporal lobe resection. The seizure semiology was analyzed using the semiological seizure classification with particular emphasis on the sequence of seizure phenomena over time and lateralizing seizure phenomena. Statistical analysis included chi-square test or Fisher's exact test. Bitemporal lobe epilepsy patients had more frequently different seizure semiology (100% vs. 40%; psemiology for the identification of bilateral TLE was high (100%) with a specificity of 60%. Lateralizing seizure phenomena had a low sensitivity (59%) but a high specificity (89%). The combination of lateralizing seizure phenomena and different seizure semiology showed a high specificity (94%) but a low sensitivity (59%). The analysis of seizure semiology including lateralizing seizure phenomena adds important clinical information to identify patients with bilateral TLE. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Iron assimilation by Azomonas macrocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Collinson, S.K.

    1989-01-01

    Iron assimilation by the gram-negative, soil diazotroph Azomonas macrocytogenes ATCC 12334 was studied. A. macrocytogenes was grown in a simple defined medium and was found to excrete two iron-binding compounds. The first compound, 3,4-dihydroxybenzoic acid (3,4DHBA) was purified and chemically identified from cell-free culture supernatants and found to promote the solubilization of iron from various iron-containing minerals. Moreover, preincubation of iron-limited growth medium with olivine or glauconite in the presence of 3,4-DHBA, supported enhanced growth of A. macrocytogenes thus suggesting a role for 3,4-DHBA in mineral-iron solubilization. However, 3,4-DHBA was not a true siderophore since it was also produced by cells growing in iron-sufficient medium and did not enhance {sup 55}Fe{sup 3+} assimilation by A. macrocytogenes. A. macrocytogenes also excreted a blue-white fluorescent compound in iron-limited media. This compound, named azoverdin, was purified in the ferrated form to 98% purity. This compound exhibited a pH-independent absorption spectrum which became pH-dependent following deferration with 8-hydroxyquinoline. Preliminary FAB mass spectral results indicated a 1:1 stoichiometry for the iron complex, and a positive reaction in the Csaky assay suggested the presence of bound hydroxylamine. Although elucidation of the exact chemical structure is in progress, these results indicated that azoverdin was chemically related to pyoverdin siderophores. Electrophoretic analysis of outer membranes of A. macrocytogenes revealed that iron-limited cells overproduced two proteins of apparent molecular mass 74 kDa and 70 kDa, which were characteristic of ferrisiderophore receptor proteins isolated from other iron-limited gram negative bacteria.

  6. Neonatal seizures triple the risk of a remote seizure after perinatal ischemic stroke

    OpenAIRE

    Fox, CK; Glass, HC; Sidney, S; Smith, SE; Fullerton, HJ

    2016-01-01

    © 2016 American Academy of Neurology. To determine incidence rates and risk factors of remote seizure after perinatal arterial ischemic stroke. Methods: We retrospectively identified a population-based cohort of children with perinatal arterial ischemic stroke (presenting acutely or in a delayed fashion) from a large Northern Californian integrated health care system. We determined incidence and predictors of a remote seizure (unprovoked seizure after neonatal period, defined as 28 days of li...

  7. Epigenetic inheritance, genetic assimilation and speciation.

    Science.gov (United States)

    Pál, C; Miklós, I

    1999-09-07

    Epigenetic inheritance systems enable the environmentally induced phenotypes to be transmitted between generations. Jablonka and Lamb (1991, 1995) proposed that these systems have a substantial role during speciation. They argued that divergence of isolated populations may be first triggered by the accumulation of (heritable) phenotypic differences that are later followed and strengthened by genetic changes. The plausibility of this idea is examined in this paper. At first, we discuss the "exploratory" behaviour of an epigenetic inheritance system on a one peak adaptive landscape. If a quantitative trait is far from the optimum, then it is advantageous to induce heritable phenotypic variation. Conversely, if the genotypes get closer to the peak, it is more favorable to canalize the phenotypic expression of the character. This process would lead to genetic assimilation. Next we show that the divergence of heritable epigenetic marks acts to reduce or to eliminate the genetic barrier between two adaptive peaks. Therefore, an epigenetic inheritance system can increase the probability of transition from one adaptive state to another. Peak shift might be initiated by (i) slight changes in the inducing environment or by (ii) genetic drift of the genes controlling epigenetic variability. Remarkably, drift-induced transition is facilitated even if phenotypic variation is not heritable. A corollary of our thesis is that evolution can proceed through suboptimal phenotypic states, without passing through a deep adaptive valley of the genotype. We also consider the consequences of this finding on the dynamics and mode of reproductive isolation. Copyright 1999 Academic Press.

  8. Efficient Data Assimilation Algorithms for Bathymetry Applications

    Science.gov (United States)

    Ghorbanidehno, H.; Kokkinaki, A.; Lee, J. H.; Farthing, M.; Hesser, T.; Kitanidis, P. K.; Darve, E. F.

    2016-12-01

    Information on the evolving state of the nearshore zone bathymetry is crucial to shoreline management, recreational safety, and naval operations. The high cost and complex logistics of using ship-based surveys for bathymetry estimation have encouraged the use of remote sensing monitoring. Data assimilation methods combine monitoring data and models of nearshore dynamics to estimate the unknown bathymetry and the corresponding uncertainties. Existing applications have been limited to the basic Kalman Filter (KF) and the Ensemble Kalman Filter (EnKF). The former can only be applied to low-dimensional problems due to its computational cost; the latter often suffers from ensemble collapse and uncertainty underestimation. This work explores the use of different variants of the Kalman Filter for bathymetry applications. In particular, we compare the performance of the EnKF to the Unscented Kalman Filter and the Hierarchical Kalman Filter, both of which are KF variants for non-linear problems. The objective is to identify which method can better handle the nonlinearities of nearshore physics, while also having a reasonable computational cost. We present two applications; first, the bathymetry of a synthetic one-dimensional cross section normal to the shore is estimated from wave speed measurements. Second, real remote measurements with unknown error statistics are used and compared to in situ bathymetric survey data collected at the USACE Field Research Facility in Duck, NC. We evaluate the information content of different data sets and explore the impact of measurement error and nonlinearities.

  9. Personalization of NonEEG-based seizure detection systems.

    Science.gov (United States)

    Cogan, D; Heydarzadeh, M; Nourani, M

    2016-08-01

    Seizures affect each patient differently, so personalization is a vital part of developing a reliable nonEEG based seizure detection system. This personalization must be done while the patient is undergoing video EEG monitoring in an epilepsy monitoring unit (EMU) because seizure detection by EEG is considered to be the ground truth. We propose the use of confidence interval analysis for determining how many seizures must be captured from a patient before we can reliably personalize such a seizure detection system for him/her. Our analysis indicates that 6 to 8 seizures are required. In addition, we create seizure likelihood tables for future use by said system by comparing the number of times a prespecified biosignal activity level is induced by seizure to the total number of occurrences of that level of activity. We focus on complex partial seizures in this paper because they are more difficult to detect than are generalized seizures.

  10. Pathophysiology of Tonic Muscle Activation During Epileptic Seizures

    DEFF Research Database (Denmark)

    Beniczky, S.; Conradsen, Isa; Wolf, P.

    2011-01-01

    Tonic seizures and the tonic phase of tonic-clonic epileptic seizures are defined as a “sustained tonic” muscle contraction. Visual inspection of the surface electromyograms (sEMG) during seizures significantly contributed to a better understanding and diagnosis of several seizure types. However......, quantitative analysis of the sEMG during the epileptic seizures has received surprisingly little attention. The aim of our study was to elucidate the pathophysiology of the tonic muscle activation during seizures. SEMG was recorded from the deltoid muscles, during 58 seizures from 18 patients (9...... with generalised tonic and 9 with tonic-clonic seizures). 18 age and gender matched normal controls simulated 90 generalised tonic seizures. We calculated the root mean square (RMS) of the amplitudes, the median frequency (MF), the relative power (RP) and the coherence. During the epileptic seizures (especially...

  11. [Epileptic seizures and syndromes in children. Classification].

    Science.gov (United States)

    Plouin, Perrine; Kaminska, Anna; Eisermann, Monika; Soufflet, Christine

    2012-12-01

    In front of any clinical paroxysmal event in childhood, the first step is to make a positive diagnostic of an epileptic seizure; for this it is necessary to eliminate non epileptic seizures which are different according to age. Then the type of seizures has to be precised, being focal or generalized. EEG will contribute to determine the epileptic syndrome according to interictal and/or ictal findings. The epilepsy syndrome is the main entity to go further in etiology and treatment. According to the type of epilepsy syndrome it will be possible to look for a structural or metabolic cause, or to perform a genetic study. The present classification of seizures and syndromes as proposed by the International League Against Epilepsy (ILAE) allows a common language in the world community as in clinical and therapeutic research.

  12. Multiple Sclerosis: Can It Cause Seizures?

    Science.gov (United States)

    ... it cause seizures? Is there any connection between multiple sclerosis and epilepsy? Answers from B Mark Keegan, M. ... article: http://www.mayoclinic.org/diseases-conditions/multiple-sclerosis/expert-answers/multiple-sclerosis/FAQ-20058138 . Mayo Clinic Footer Legal Conditions ...

  13. Epilepsy Risk Factors Following Neonatal Seizures

    OpenAIRE

    J Gordon Millichap

    2004-01-01

    Clinical and polysomnographic risk factors as early predictors for the development of postnatal epilepsy were determined in 158 infants presenting with two or more seizures, in a study at Hospital Sao Lucas, Porto Alegre, Brazil.

  14. Serum Prolactin in Diagnosis of Epileptic Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-09-01

    Full Text Available The results of studies in databases and references concerning serum prolactin levels (PRL in patients with suspected seizures were rated for quality and analyzed by members of the Therapeutics Subcommittee of the American Academy of Neurology.

  15. Seizures and Munchausen Syndrome by Proxy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-05-01

    Full Text Available The prevalence, morbidity and mortality, diagnosis and management of cases of fabricated seizures and child abuse (Munchausen syndrome by proxy (MSbp are assessed by pediatricians at the University of Wales College of Medicine, Cardiff, UK.

  16. Formulation of scale transformation in a stochastic data assimilation framework

    Science.gov (United States)

    Liu, Feng; Li, Xin

    2017-06-01

    Understanding the errors caused by spatial-scale transformation in Earth observations and simulations requires a rigorous definition of scale. These errors are also an important component of representativeness errors in data assimilation. Several relevant studies have been conducted, but the theory of the scale associated with representativeness errors is still not well developed. We addressed these problems by reformulating the data assimilation framework using measure theory and stochastic calculus. First, measure theory is used to propose that the spatial scale is a Lebesgue measure with respect to the observation footprint or model unit, and the Lebesgue integration by substitution is used to describe the scale transformation. Second, a scale-dependent geophysical variable is defined to consider the heterogeneities and dynamic processes. Finally, the structures of the scale-dependent errors are studied in the Bayesian framework of data assimilation based on stochastic calculus. All the results were presented on the condition that the scale is one-dimensional, and the variations in these errors depend on the differences between scales. This new formulation provides a more general framework to understand the representativeness error in a non-linear and stochastic sense and is a promising way to address the spatial-scale issue.

  17. Data assimilation with state alignment using the EnKF

    Science.gov (United States)

    Makris, A.; Papadakis, N.

    2012-12-01

    Sequential assimilation methods allow tracking physical states using dynamic priors and external observations of the studied system. However, when dense image satellite observations are available, such approaches realize a correction of the amplitude of the different state values but do not incorporate the spatial errors of structure positions. In the case of the position of a vortex, for example, when there is misfit between state and observation, the processes can be long to converge and even diverge when high dimensional state spaces are treated with few iterations of the assimilation methods as it is the case in operational algorithms. In this paper, we tackle this issue by decomposing the state of the system to displacement and amplitude varibales. We then propose an alignment method based on object detection methods that uses visual correspondences between the physical state model and the structural information given by a sequence of images observing the phenomena. The ensemble Kalman filter (EnKF) is modified in order to perform sequentially the alignment followed by the amplitude correction. The experimental evaluation of the method using both simulated and real data shows accurate structure detection and a faster convergence rate of the assimilation method.

  18. Using a structured questionnaire improves seizure description by medical students

    OpenAIRE

    Kapadia, Saher; Shah, Hemang; McNair, Nancy; Pruitt, J. Ned; Murro, Anthony; Park, Yong

    2016-01-01

    Objectives The purpose of this study was to evaluate a structured questionnaire for improving a medical students? ability to identify, describe and interpret a witnessed seizure. Methods Ninety two 3rd year medical students, blinded to seizure diagnosis, viewed videos of a primary generalized seizure and a complex partial seizure.? Students next completed an unstructured questionnaire that asked the students to describe the seizure video recordings. The students then completed a structured qu...

  19. 15 CFR 904.501 - Notice of seizure.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Notice of seizure. 904.501 Section 904... Seizure and Forfeiture Procedures § 904.501 Notice of seizure. Within 60 days from the date of the seizure, NOAA will serve the Notice of Seizure as provided in § 904.3 to the owner or consignee, if known or...

  20. Epidemiology of Acute Symptomatic Seizures among Adult Medical Admissions

    OpenAIRE

    Nwani, Paul Osemeke; Nwosu, Maduaburochukwu Cosmas; Nwosu, Monica Nonyelum

    2016-01-01

    Acute symptomatic seizures are seizures occurring in close temporal relationship with an acute central nervous system (CNS) insult. The objective of the study was to determine the frequency of presentation and etiological risk factors of acute symptomatic seizures among adult medical admissions. It was a two-year retrospective study of the medical files of adults patients admitted with acute symptomatic seizures as the first presenting event. There were 94 cases of acute symptomatic seizures ...

  1. Hyponatremia-induced seizure during carbamazepine treatment.

    Science.gov (United States)

    Holtschmidt-Täschner, Bettina; Soyka, Michael

    2007-01-01

    We report the case of a 54-year-old woman who was admitted for benzodiazepine withdrawal. After 6 weeks of carbamazepine treatment (600, then 200 mg) the patient suddenly suffered from a grand mal seizure. Laboratory findings revealed a clinical significant hyponatremia of Na 125 mmol/l (baseline: 143 mmol/l). CCT and ECG were normal. To our knowledge, this is the first description of a seizure related to hyponatremia in an adult carbamazepine-treated patient.

  2. Ketogenic diet: Predictors of seizure control.

    Science.gov (United States)

    Agarwal, Nitin; Arkilo, Dimitrios; Farooq, Osman; Gillogly, Cynthia; Kavak, Katelyn S; Weinstock, Arie

    2017-01-01

    The ketogenic diet is an effective non-pharmacologic treatment for medically resistant epilepsy. The aim of this study was to identify any predictors that may influence the response of ketogenic diet. A retrospective chart review for all patients with medically resistant epilepsy was performed at a tertiary care epilepsy center from 1996 to 2012. Patient- and diet-related variables were evaluated with respect to seizure reduction at 1, 3, 6, 9 and 12-month intervals and divided into four possible outcome classes. Sixty-three patients met inclusion. Thirty-seven (59%) reported >50% seizure reduction at 3 months with 44% and 37% patients benefiting at 6-month and 12-month follow up, respectively. A trend toward significant seizure improvement was noted in 48% patients with seizure onset >1 year at 12-month (p = 0.09) interval and in 62% patients with >10 seizure/day at 6-month interval (p = 0.054). An ordinal logistic regression showed later age of seizure to have higher odds of favorable response at 1-month (p = 0.005) and 3-month (p = 0.013) follow up. Patients with non-fasting diet induction were more likely to have a favorable outcome at 6 months (p = 0.008) as do females (p = 0.037) and those treated with higher fat ratio diet (p = 0.034). Our study reports the effectiveness of ketogenic diet in children with medically resistant epilepsy. Later age of seizure onset, female gender, higher ketogenic diet ratio and non-fasting induction were associated with better odds of improved seizure outcome. A larger cohort is required to confirm these findings.

  3. Seizure disorders in Systemic Lupus Erythematosus

    Science.gov (United States)

    Hanly, John G.; Urowitz, Murray B.; Su, Li; Gordon, Caroline; Bae, Sang-Cheol; Sanchez-Guerrero, Jorge; Romero-Diaz, Juanita; Wallace, Daniel J; Clarke, Ann E.; Ginzler, E.M.; Merrill, Joan T.; Isenberg, David A.; Rahman, Anisur; Petri, M.; Fortin, Paul R.; Gladman, D. D.; Bruce, Ian N.; Steinsson, Kristjan; Dooley, M.A.; Khamashta, Munther A.; Alarcón, Graciela S.; Fessler, Barri J.; Ramsey-Goldman, Rosalind; Manzi, Susan; Zoma, Asad A.; Sturfelt, Gunnar K.; Nived, Ola; Aranow, Cynthia; Mackay, Meggan; Ramos-Casals, Manuel; van Vollenhoven, R.F.; Kalunian, Kenneth C.; Ruiz-Irastorza, Guillermo; Lim, Sam; Kamen, Diane L.; Peschken, Christine A.; Inanc, Murat; Theriault, Chris; Thompson, Kara; Farewell, Vernon

    2015-01-01

    Objective To describe the frequency, attribution, outcome and predictors of seizures in SLE Methods The Systemic Lupus International Collaborating Clinics (SLICC) performed a prospective inception cohort study. Demographic variables, global SLE disease activity (SLEDAI-2K), cumulative organ damage (SLICC/ACR Damage Index (SDI)) and neuropsychiatric events were recorded at enrollment and annually. Lupus anticoagulant, anticardiolipin, anti-β2 glycoprotein-I, anti-ribosomal P and anti-NR2 glutamate receptor antibodies were measured at enrollment. Physician outcomes of seizures were recorded. Patient outcomes were derived from the SF-36 mental (MCS) and physical (PCS) component summary scores. Statistical analyses included Cox and linear regressions. Results The cohort was 89.4% female with a mean follow up of 3.5±2.9 years. 75/1631 (4.6%) had ≥1 seizure, the majority around the time of SLE diagnosis. Multivariate analysis indicated a higher risk of seizures with African race/ethnicity (HR(CI):1.97 (1.07–3.63); p=0.03) and lower education status (1.97 (1.21–3.19); pattributed to SLE frequently resolved (59/78(76%)) in the absence of anti-seizure drugs. There was no significant impact on the MCS or PCS scores. Anti-malarial drugs in absence of immunosuppressive agents were associated with reduced seizure risk (0.07(0.01–0.66); p=0.03). Conclusion Seizures occurred close to SLE diagnosis, in patients with African race/ethnicity, lower educational status and cumulative organ damage. Most seizures resolved without a negative impact on health-related quality of life. Anti-malarial drugs were associated with a protective effect. PMID:22492779

  4. Methodological Developments in Geophysical Assimilation Modeling

    Science.gov (United States)

    Christakos, George

    2005-06-01

    This work presents recent methodological developments in geophysical assimilation research. We revisit the meaning of the term "solution" of a mathematical model representing a geophysical system, and we examine its operational formulations. We argue that an assimilation solution based on epistemic cognition (which assumes that the model describes incomplete knowledge about nature and focuses on conceptual mechanisms of scientific thinking) could lead to more realistic representations of the geophysical situation than a conventional ontologic assimilation solution (which assumes that the model describes nature as is and focuses on form manipulations). Conceptually, the two approaches are fundamentally different. Unlike the reasoning structure of conventional assimilation modeling that is based mainly on ad hoc technical schemes, the epistemic cognition approach is based on teleologic criteria and stochastic adaptation principles. In this way some key ideas are introduced that could open new areas of geophysical assimilation to detailed understanding in an integrated manner. A knowledge synthesis framework can provide the rational means for assimilating a variety of knowledge bases (general and site specific) that are relevant to the geophysical system of interest. Epistemic cognition-based assimilation techniques can produce a realistic representation of the geophysical system, provide a rigorous assessment of the uncertainty sources, and generate informative predictions across space-time. The mathematics of epistemic assimilation involves a powerful and versatile spatiotemporal random field theory that imposes no restriction on the shape of the probability distributions or the form of the predictors (non-Gaussian distributions, multiple-point statistics, and nonlinear models are automatically incorporated) and accounts rigorously for the uncertainty features of the geophysical system. In the epistemic cognition context the assimilation concept may be used to

  5. Seizure Freedom After Limited Hippocampal Radiofrequency Thermocoagulation.

    Science.gov (United States)

    Li, Han-Tao; Lee, Ching-Yi; Lim, Siew-Na; Chang, Chun-Wei; Lee, Shih-Tseng; Wu, Tony

    2016-12-01

    Surgical interventions are often used for freedom from seizure in patients with drug-resistant mesial temporal lobe epilepsy. A patient with seizure foci in the left mesiotemporal region underwent limited-size stereotactic radiofrequency thermocoagulation (RF-TC) over the left hippocampus. A 37-year-old woman with febrile convulsion in her childhood was admitted to our neurologic department with complex partial seizure with secondary generalization. Electroencephalography showed epileptogenic focus mainly from the left mesiotemporal region, and magnetic resonance imaging confirmed a left hippocampal atrophy. Because of failure to control seizure after use of several antiepileptic drugs, drug-resistant mesial temporal lobe epilepsy was diagnosed. RF-TC was done in the left hippocampus. Unique features of our technique include intraoperative electroencephalography recordings directly from electrodes on the left hippocampus, an aura sensation provoked during the low-temperature test thermocoagulation, and therapeutic thermocoagulation performed via a Radionics radiofrequency lead. In the 16-week period following the surgery, the patient experienced no seizure attacks and no significant postoperative adverse effects or memory impairments. Compared with other reports using RF-TC, our case demonstrates a 1-step minimally invasive surgery that reduces hippocampal volume loss, shortens the length of hospital stay, decreases the occurrence of postoperative infection, and achieves good outcomes for epilepsy control. Favorable seizure control was achieved with minimally invasive RF-TC. Further use of this technique is warranted in cases of drug-resistant mesial temporal lobe epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Sudden infant death syndrome, sleep, and seizures.

    Science.gov (United States)

    Hoppenbrouwers, Toke

    2015-06-01

    benign febrile seizures seen in 7% of infants before 6 months play a role in the terminal pathway in a subset of sudden infant death syndrome victims. Supporting evidence: (1) lack of 5-hydroxitryptamine, one consistent finding in sudden infant death syndrome that Kinney et al coined a developmental serotonopathy, is consistent with risk for seizures. (2) Non-rapid eye movement sleep increasing during the age of highest risk for sudden infant death syndrome facilitates some seizures (seizure gate). (3) Sudden unexpected death in epilepsy is associated with severe hypoxemia and hypercapnia during postictal generalized electroencephalographic (EEG) suppression. In toddlers, sudden unexplained deaths are associated with hippocampal abnormalities and some seizures. (4) The sudden nature of both deaths warrants an exploration of similarities in the terminal pathway. Moreover, sudden infant death syndrome, febrile seizures, sudden unexplained death in childhood, and sudden unexpected death in epilepsy share some of the following risk factors: prone sleeping, infections, hyperthermia, preterm birth, male gender, maternal smoking, and mutations in genes that regulate sodium channels. State-of-the-art molecular studies can be exploited to test this hypothesis. © The Author(s) 2014.

  7. Intravenous Carbamazepine for Adults With Seizures.

    Science.gov (United States)

    Vickery, P Brittany; Tillery, Erika E; DeFalco, Alicia Potter

    2018-03-01

    To review the pharmacology, pharmacokinetics, efficacy, safety, dosage and administration, potential drug-drug interactions, and place in therapy of the intravenous (IV) formulation of carbamazepine (Carnexiv) for the treatment of seizures in adult patients. A comprehensive PubMed and EBSCOhost search (1945 to August 2017) was performed utilizing the keywords carbamazepine, Carnexiv, carbamazepine intravenous, IV carbamazepine, seizures, epilepsy, and seizure disorder. Additional data were obtained from literature review citations, manufacturer's product labeling, and Lundbeck website as well as Clinicaltrials.gov and governmental sources. All English-language trials evaluating IV carbamazepine were analyzed for this review. IV carbamazepine is FDA approved as temporary replacement therapy for treatment of adult seizures. Based on a phase I trial and pooled data from 2 open-label bioavailability studies comparing oral with IV dosing, there was no noted indication of loss of seizure control in patients switched to short-term replacement antiepileptic drug therapy with IV carbamazepine. The recommended dose of IV carbamazepine is 70% of the patient's oral dose, given every 6 hours via 30-minute infusions. The adverse effect profile of IV carbamazepine is similar to that of the oral formulation, with the exception of added infusion-site reactions. IV carbamazepine is a reasonable option for adults with generalized tonic-clonic or focal seizures, previously stabilized on oral carbamazepine, who are unable to tolerate oral medications for up to 7 days. Unknown acquisition cost and lack of availability in the United States limit its use currently.

  8. Acute Symptomatic Seizures Caused by Electrolyte Disturbances.

    Science.gov (United States)

    Nardone, Raffaele; Brigo, Francesco; Trinka, Eugen

    2016-01-01

    In this narrative review we focus on acute symptomatic seizures occurring in subjects with electrolyte disturbances. Quite surprisingly, despite its clinical relevance, this issue has received very little attention in the scientific literature. Electrolyte abnormalities are commonly encountered in clinical daily practice, and their diagnosis relies on routine laboratory findings. Acute and severe electrolyte imbalances can manifest with seizures, which may be the sole presenting symptom. Seizures are more frequently observed in patients with sodium disorders (especially hyponatremia), hypocalcemia, and hypomagnesemia. They do not entail a diagnosis of epilepsy, but are classified as acute symptomatic seizures. EEG has little specificity in differentiating between various electrolyte disturbances. The prominent EEG feature is slowing of the normal background activity, although other EEG findings, including various epileptiform abnormalities may occur. An accurate and prompt diagnosis should be established for a successful management of seizures, as rapid identification and correction of the underlying electrolyte disturbance (rather than an antiepileptic treatment) are of crucial importance in the control of seizures and prevention of permanent brain damage.

  9. Anoxic seizures: self-terminating syncopes.

    Science.gov (United States)

    Stephenson, J B

    2001-01-01

    This review focuses on anoxic seizures induced by self terminating syncopes in the young. Anoxic seizures are nonepileptic events consequent upon abrupt interruption of the energy supply to metabolically active cerebral neurones. Anoxic seizures are the most common paroxysmal events misdiagnosed as epilepsy. Neurally mediated syncopes have numerous appellations, especially in the young. This proliferation of terminology likely results from uncertainty regarding pathophysiology. The most important type of self-limiting syncope from the point of view of diagnostic difficulty has been called neurocardiogenic or vasovagal syncope and reflex anoxic seizure, amongst other names: this review includes a video clip of such a child with prolonged asystole. It also includes a detailed case history emphasising the feelings of a patient with this type of syncope who was misdiagnosed as having epilepsy for many years. The second class of self-terminating syncope discussed and illustrated on video is the so-called breath-holding spell of young children. The third example illustrated is the compulsive Valsalva manoeuvre of individuals with autistic spectrum disorder, in which anoxic seizures - as shown on the video clips - are easily misdiagnosed as epileptic seizures, with unfortunate consequences.

  10. [Seizures in neurofibromatosis. What is the risk?].

    Science.gov (United States)

    Drouet, A

    2011-12-01

    The prevalence and the type of seizures associated with neurofibromatosis 1 (NF1) and 2 (NF2) are not adequately characterized. NF1 has a birth incidence of one in 2500, and NF2 one in 25000. Seizures are an occasional complication in NF1 patients and there is no data for NF2 patients. Central nervous system tumors are always suspected, since NF1 and NF2 are caused by mutations in tumor suppressor gene controlling cell proliferation and differentiation. The aim of this article is to provide a synthetic overview about epilepsy associated with NF1 and NF2 based on published studies. In NF1, the type of seizures and their response to therapy are reported, the heterogeneity of etiology is also discussed. For NF2 patients, no specific data are available; the current knowledge comes from series of NF2 patients for which seizures has revealed the disease or from isolated case reports of tumors associated with seizures. Cryptogenic epilepsy without anatomic defect is likely to be related to NF1, while seizures seem to be secondary to leptomeningeal tumors (meningioma, meningioangiomatosis) in NF2 patients. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  11. Cardiopulmonary complications during pediatric seizures: A prelude to understanding SUDEP

    Science.gov (United States)

    Singh, Kanwaljit; Katz, Eliot S.; Zarowski, Marcin; Loddenkemper, Tobias; Llewellyn, Nichelle; Manganaro, Sheryl; Gregas, Matt; Pavlova, Milena; Kothare, Sanjeev V.

    2017-01-01

    Summary Purpose Sudden unexpected death in epilepsy (SUDEP) is an important, unexplained cause of death in epilepsy. Role of cardiopulmonary abnormalities in the pathophysiology of SUDEP is unclear in the pediatric population. Our objective was to assess cardiopulmonary abnormalities during epileptic seizures in children, with the long-term goal of identifying potential mechanisms of SUDEP. Methods We prospectively recorded cardiopulmonary functions using pulse-oximetry, electrocardiography (ECG), and respiratory inductance plethysmography (RIP). Logistic regression was used to evaluate association of cardiorespiratory findings with seizure characteristics and demographics. Key Findings We recorded 101 seizures in 26 children (average age 3.9 years). RIP provided analyzable data in 78% and pulse-oximetry in 63% seizures. Ictal central apnea was more prevalent in patients with younger age (p = 0.01), temporal lobe (p seizures (p seizures (p seizures (p seizures (p seizures (p seizures (p seizures (p = 0.01). Ictal and postictal bradycardia were directly associated (p seizures (p epileptic seizures are associated with predictable patient and seizure characteristics, including seizure subtype and duration. PMID:23731396

  12. Clients' assimilation of experiences of their therapists.

    Science.gov (United States)

    Mosher, James K; Stiles, William B

    2009-12-01

    In this study, we examined how clients internalize their therapists, understanding this phenomenon through the lens of the assimilation model, a theory of psychological change. The assimilation model describes people as comprised of multiple voices, each voice being a representation of interrelated experiences organized around significant people or events. In this study, we interviewed five former psychotherapy clients and asked them to describe how they experienced, and continue to experience, their therapists internally. On the basis of these interviews, we extended the assimilation model by constructing an account of how clients' experiences of their therapists are internalized. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  13. Serum Prolactin Level after Febrile Seizure versus Epileptic Seizure in 6-Month-Old to 5-Year-Old Children

    OpenAIRE

    Zahra Yekta; Nader Pashapoor; Ali Aghayar Macooie; Mohammad Karamyar

    2009-01-01

    Background: Serum prolactin level has been used as analternative determinant to help differentiate epileptic fromnon-epileptic seizures. We aimed to analyze the associationbetween serum prolactin concentration and epileptic seizureversus febrile seizure as well as seizure duration, single versusmultiple seizure attacks and time lapse between seizure onsetand blood sampling.Methods: Seventy patients aged 6 months to 5 years withseizure who admitted to the emergency department betweenMarch 2004...

  14. The adult seizure and social outcomes of children with partial complex seizures.

    Science.gov (United States)

    Camfield, Carol S; Camfield, Peter R

    2013-02-01

    Most intellectually normal children with focal epilepsy have partial complex or focal with secondary generalization seizures without a precise epilepsy syndrome. Their long-term outcome is largely unknown. Cases were identified from the population-based Nova Scotia Childhood Epilepsy cohort. Those eligible had seizure onset at 1 month to 16 years between 1977 and 1985, normal intelligence, ≥10 years of follow-up, only focal seizures and no benign epilepsy syndromes. There were 108 patients with partial complex with or without secondary generalization as the only seizure type(s) throughout (partial complex group) and 80 with secondary generalization as the only seizure type (secondary generalization group). Average age ± standard deviation at onset was 7.3 ± 4.5 years and follow-up was 27.9 ± 5.4 years. At follow-up, 57% of the partial complex group were in remission versus 81% of the secondary generalization group (P = 0.001). The partial complex group was more likely to be intractable or have undergone epilepsy surgery (36% versus 5%, P = 0.000). In the partial complex group, 28% had seizure free versus 5% in the secondary generalized group (P = 0.000). More patients in the partial complex group had undergone mental health assessments (59% versus 32%, P = 0.000), and 33% had a psychiatric diagnosis versus 15% in the secondary generalized group (P = 0.004). More patients with partial complex seizures had specific learning disorders (63% versus 45%, P = 0.03). Seven markers of poor social outcome were more common in patients with partial complex seizures (>2 markers: 34% versus 10%, P = 0.000). During 25-30 years of follow-up, >50% of intellectually normal patients with childhood-onset partial complex seizures had difficult-to-control seizures and learning and psychiatric/social problems. Most with secondary generalized seizures only had remission and better academic and psychiatric/social outcomes.

  15. Epileptic seizures in Neuro-Behcet disease: why some patients develop seizure and others not?

    Science.gov (United States)

    Kutlu, Gulnihal; Semercioglu, Sencer; Ucler, Serap; Erdal, Abidin; Inan, Levent E

    2015-03-01

    Behcet disease (BD) is a chronic relapsing inflammatory disorder. Neuro BD (NBD) is seen in approximately 5% of all patients. The aim of this study is to investigate the frequency, type and prognosis of epileptic seizures in different forms of NBD. All files of 42 patients with NBD were evaluated between 2006 and 2012, retrospectively. The demographic data, the presentation of NBD, clinical findings including seizures, EEG and neuroimaging findings were reviewed. The mean age of patients was 35.02±8.43 years. Thirty (71.4%) patients were male; the remaining 12 of them were female. Twenty-four patients had brainstem lesions; 16 patients had cerebral venous thrombosis. Spinal cord involvement was seen in two patients. Seven patients had epileptic seizures (six partial onset seizures with or without secondary generalization). Six of them had cerebral sinus thrombosis (CVT). Four patients had a seizure as the first symptom of the thrombosis. One patient had late onset seizure due to chronic venous infarct. The other patient with seizure had brainstem involvement. The remaining was diagnosed as epilepsy before the determination of NBD. CVT seen in BD seems to be the main risk factor for epileptic seizures in patients with NBD. The prognosis is usually good especially in patients with CVT. Epileptic seizures in patients with brainstem involvement may be an indicator for poor prognosis. Superior sagittal thrombosis or cortical infarct would be predictor of seizures occurrence because of the high ratio in patients with seizures. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  16. Asymmetric seizure termination in primary and secondary generalized tonic-clonic seizures.

    Science.gov (United States)

    Walser, Gerald; Unterberger, Iris; Dobesberger, Judith; Embacher, Norbert; Falkenstetter, Tina; Larch, Julia; Kuchukhidze, Giorgi; Gotwald, Thaddaeus; Ortler, Martin; Bauer, Gerhard; Trinka, Eugen

    2009-09-01

    In temporal lobe epilepsies an asymmetric termination (AST) of the clonic phase of secondary generalized tonic-clonic seizures (sGTCS) reliably lateralizes the side of seizure onset. The last clonic activity occurs ipsilateral to the side of the seizure onset zone. We compared the prevalence and lateralizing value of AST in sGTCS of frontal and temporal lobe origin as well as in primary generalized tonic-clonic seizures (pGTCS). We analyzed 177 seizures in 84 consecutive patients. Forty-one patients had temporal lobe epilepsy (TLE), 24 frontal lobe epilepsy (FLE), and 19 had nonfocal (primary) generalized epilepsies (GE). All patients underwent intensive video-EEG (electroencephalography) monitoring, high-resolution magnetic resonance imaging (MRI), neuropsychological testing, and single photon emission computed tomography/positron emission tomography (SPECT/PET) when feasible. Two investigators blinded for diagnosis, EEG, and imaging data assessed frequency and side of the last clonic jerk. AST occurred in 63% of patients with TLE (47% of seizures), in 71% with FLE (60% of seizures), and in 42% with GE (21% of seizures). These results were not significant for patients, but significant for seizures in TLE versus GE and in FLE versus GE (p seizure onset was 74% (p = 0.003) in TLE and 75% (p = 0.008) in FLE. AST in sGTCS lateralizes the side of seizure onset in TLE and in FLE to the ipsilateral hemisphere with a high PPV. However, AST was also observed in GE. Therefore, asymmetric clinical signs should not inevitably lead to the assumption of focal epilepsy syndromes.

  17. The importance of peers: assimilation patterns among second-generation Turkish immigrants in Western Europe

    NARCIS (Netherlands)

    Ali, S.; Fokkema, C.M.

    2011-01-01

    The two dominant approaches to immigrant assimilation, segmented assimilation and "new" assimilation theories, have been successful at reporting and analyzing between-group differences in assimilation patterns. However, studies of assimilation generally do not address differences at the individual

  18. Reviews and syntheses: Systematic Earth observations for use in terrestrial carbon cycle data assimilation systems

    Directory of Open Access Journals (Sweden)

    M. Scholze

    2017-07-01

    Full Text Available The global carbon cycle is an important component of the Earth system and it interacts with the hydrology, energy and nutrient cycles as well as ecosystem dynamics. A better understanding of the global carbon cycle is required for improved projections of climate change including corresponding changes in water and food resources and for the verification of measures to reduce anthropogenic greenhouse gas emissions. An improved understanding of the carbon cycle can be achieved by data assimilation systems, which integrate observations relevant to the carbon cycle into coupled carbon, water, energy and nutrient models. Hence, the ingredients for such systems are a carbon cycle model, an algorithm for the assimilation and systematic and well error-characterised observations relevant to the carbon cycle. Relevant observations for assimilation include various in situ measurements in the atmosphere (e.g. concentrations of CO2 and other gases and on land (e.g. fluxes of carbon water and energy, carbon stocks as well as remote sensing observations (e.g. atmospheric composition, vegetation and surface properties.We briefly review the different existing data assimilation techniques and contrast them to model benchmarking and evaluation efforts (which also rely on observations. A common requirement for all assimilation techniques is a full description of the observational data properties. Uncertainty estimates of the observations are as important as the observations themselves because they similarly determine the outcome of such assimilation systems. Hence, this article reviews the requirements of data assimilation systems on observations and provides a non-exhaustive overview of current observations and their uncertainties for use in terrestrial carbon cycle data assimilation. We report on progress since the review of model-data synthesis in terrestrial carbon observations by Raupach et al.(2005, emphasising the rapid advance in relevant space

  19. Assimilation of Satellite-Derived Skin Temperature Observations into Land Surface Models

    Science.gov (United States)

    Reichle, Rolf H.; Kumar, Sujay V.; Mahanama, P. P.; Koster, Randal D.; Liu, Q.

    2010-01-01

    Land surface (or "skin") temperature (LST) lies at the heart of the surface energy balance and is a key variable in weather and climate models. Here we assimilate LST retrievals from the International Satellite Cloud Climatology Project (ISCCP) into the Noah and Catchment (CLSM) land surface models using an ensemble-based, off-line land data assimilation system. LST is described very differently in the two models. A priori scaling and dynamic bias estimation approaches are applied because satellite and model LST typically exhibit different mean values and variability. Performance is measured against 27 months of in situ measurements from the Coordinated Energy and Water Cycle Observations Project at 48 stations. LST estimates from Noah and CLSM without data assimilation ("open loop") are comparable to each other and superior to that of ISCCP retrievals. For LST, RMSE values are 4.9 K (CLSM), 5.6 K (Noah), and 7.6 K (ISCCP), and anomaly correlation coefficients (R) are 0.62 (CLSM), 0.61 (Noah), and 0.52 (ISCCP). Assimilation of ISCCP retrievals provides modest yet statistically significant improvements (over open loop) of up to 0.7 K in RMSE and 0.05 in anomaly R. The skill of surface turbulent flux estimates from the assimilation integrations is essentially identical to the corresponding open loop skill. Noah assimilation estimates of ground heat flux, however, can be significantly worse than open loop estimates. Provided the assimilation system is properly adapted to each land model, the benefits from the assimilation of LST retrievals are comparable for both models.

  20. Assimilative and non-assimilative color spreading in the watercolor configuration

    Directory of Open Access Journals (Sweden)

    Eiji eKimura

    2014-09-01

    Full Text Available A colored line flanking a darker contour will appear to spread its color onto an area enclosed by the line (watercolor effect. The watercolor effect has been characterized as an assimilative effect, but non-assimilative color spreading has also been demonstrated in the same spatial configuration; e.g., when a black inner contour (IC is paired with a blue outer contour (OC, yellow color spreading can be observed. To elucidate visual mechanisms underlying these different color spreading effects, this study investigated the effects of luminance ratio between the double contours on the induced color by systematically manipulating the IC and OC luminances (Experiment 1 as well as the background luminance (Experiment 2. The results showed that the luminance conditions suitable for assimilative and non-assimilative color spreading were nearly opposite. When the Weber contrast of the IC to the background luminances (IC contrast was smaller than that of the OC (OC contrast, the induced color became similar to the IC color (assimilative spreading. In contrast, when the OC contrast was smaller than or equal to the IC contrast, the induced color became yellow (non-assimilative spreading. Extending these findings, Experiment 3 showed that bilateral color spreading, e.g., assimilative spreading on one side and non-assimilative spreading on the other side, can also be observed in the watercolor configuration. These results suggest that the assimilative and non-assimilative spreading were mediated by different visual mechanisms. The properties of the assimilative spreading are consistent with the model proposed to account for neon color spreading [Grossberg, S. & Mingolla, E. (1985 Percept. Psychophys., 38, 141-171] and extended for the watercolor effect [Pinna, B., & Grossberg, S. (2005 J. Opt. Soc. Am. A, 22, 2207-2221]. However, the present results suggest that additional mechanisms are needed to account for the non-assimilative color spreading.

  1. THE SOCIAL CONTEXT OF ASSIMILATION: TESTING IMPLICATIONS OF SEGMENTED ASSIMILATION THEORY*

    OpenAIRE

    Xie, Yu; Greenman, Emily

    2011-01-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between s...

  2. IS ASSIMILATION THEORY DEAD? THE EFFECT OF ASSIMILATION ON ADOLESCENT WELL-BEING

    OpenAIRE

    Greenman, Emily; Xie, Yu

    2008-01-01

    The relationship between assimilation and the well-being of immigrant children has been the focus of debate in the recent sociological literature. Much of this work has questioned whether classical theories of immigrant adaptation, which assumed assimilation to be an integral part of the process of upward mobility for immigrants, are still applicable to today’s immigrant children. This study reevaluates the applicability of classical assimilation theory with a comprehensive empirical assessme...

  3. Seizures and Teens: Surgery for Seizures--What's It All About?

    Science.gov (United States)

    Duchowny, Michael S.; Dean, Patricia

    2006-01-01

    Nearly 1 out of 2 children and teens with seizures may need to take medications throughout their lives. At least 25% will develop a condition called refractory epilepsy--meaning that their seizures do not respond to medical therapy. For these children and teens, non-drug therapies such as brain surgery are available that may offer a chance to…

  4. Seizures and Teens: When Seizures Aren't the Only Problem

    Science.gov (United States)

    Kanner, Andres M.; Shafer, Patricia O.

    2006-01-01

    Some teenagers with epilepsy only have to deal with seizures, which can be tough enough, but for other teens, seizures are not the only problem. Parents and caregivers often report changes in their teens' abilities to think clearly, learn in school, or remain focused in class. Mood and other behavioral problems may also be seen. It is critical…

  5. At first glance, transparency enhances assimilation

    NARCIS (Netherlands)

    Koning, A.R.; Weert, C.M.M. de; Lier, R.J. van

    2008-01-01

    We investigated the role of transparency, perceptual grouping, and presentation time on perceived lightness. Both transparency and perceptual grouping have been found to result in assimilation effects, but only for ambiguous stimulus displays and with specific attentional instructions. By varying

  6. ERP ASSIMILATION: AN END-USER APPROACH

    Directory of Open Access Journals (Sweden)

    Hurbean Luminita

    2013-07-01

    The paper discusses the ERP adoption based on the IT assimilation theory. The ERP lifecycle is associated with the IT assimilation steps. We propose a distribution of these steps along the lifecycle. Derived from the findings in the reviewed literature we will focus the cultural factors, in particular those related to the end-users (determined as a major impact factor in our previous study: Negovan et al., 2011. Our empirical study is centred on the end-users perspective and it tries to determine if and how their behaviour affects the achievement of the ERP assimilation steps. The paper reasons that organizations that understand the IT assimilation steps correlated to the ERP implementation critical factors are more likely to implement and use ERP successfully.

  7. Data assimilation in integrated hydrological modelling

    DEFF Research Database (Denmark)

    Rasmussen, Jørn

    Integrated hydrological models are useful tools for water resource management and research, and advances in computational power and the advent of new observation types has resulted in the models generally becoming more complex and distributed. However, the models are often characterized by a high...... using both synthetic data and real observations. Groundwater head and stream discharge observations are assimilated in an integrated hydrological model, with the aim of updating the groundwater head, stream discharge and water level, and model parameters. When synthetically generated observations......, two bias-aware data assimilation algorithms are tested and were shown to successfully estimate the bias of most observations. The data assimilation framework was applied to real observations and an improvement in stream discharge was obtained compared to a deterministic model without data assimilation...

  8. The subcortical hidden side of focal motor seizures: evidence from micro-recordings and local field potentials.

    Science.gov (United States)

    Devergnas, Annaelle; Piallat, Brigitte; Prabhu, Shivadatta; Torres, Napoleon; Louis Benabid, Alim; David, Olivier; Chabardès, Stephan

    2012-07-01

    Focal motor seizures are characterized by transient motor behaviour that occurs simultaneously with paroxystic activity in the controlateral motor cortex. The implication of the basal ganglia has already been shown for generalized seizure but the propagation pathways from the motor cortex towards the basal ganglia during focal motor seizures are largely unknown. With a better knowledge of those pathways, a therapeutic modulation for reducing drug resistant motor epilepsy could be considered. Here, we recorded single-unit activities and local field potentials in the basal ganglia of two Macaca fascicularis in which acute focal motor seizures were induced by the injection of penicillin over the arm motor cortex territory. Each neuron was characterized using its mean firing rate and its type of firing pattern during interictal periods and seizures. Time-frequency analyses of local field potentials and electroencephalographic signals were used to assess dynamic changes occurring during seizure at a larger spatial level. The firing rate of neurons of input stages of basal ganglia (subthalamic nucleus and putamen) and those from the external part of the globus pallidus were significantly higher during seizures as compared to interictal periods. During seizures, the proportion of oscillatory neurons in subthalamic nucleus (71%), external globus pallidus (45%) and putamen (53%) significantly increased in comparison to interictal periods. Rhythmic activity was synchronized with ictal cortical spikes in external globus pallidus and subthalamic nucleus, but not in the putamen which oscillated faster than motor cortex. In contrast, no significant modification of the firing rate of the output stages of basal ganglia (internal part of the globus pallidus, substantia nigra pars reticulata) could be found during seizures. The local field potentials of subthalamic nucleus and external globus pallidus changed abruptly at the onset of the seizure, showing synchronization with the

  9. Seizure frequency and characteristics in children with Down syndrome.

    Science.gov (United States)

    Goldberg-Stern, H; Strawsburg, R H; Patterson, B; Hickey, F; Bare, M; Gadoth, N; Degrauw, T J

    2001-10-01

    Seizures have not historically been considered a major component of Down syndrome. We examined the prevalence of epileptic seizures in 350 children and adolescents with Down syndrome evaluated at a regional center between 1985 and 1997. Results showed that 28 patients (8%) had epileptic seizures: 13 (47%) partial seizures; 9 (32%) infantile spasms, and 6 (21%) generalized tonic-clonic seizures. In the infantile spasm group, there was no relationship between the initial electroencephalogram (EEG) pattern and response to treatment or long-term seizure control, or between type of pharmacologic treatment (valproic acid, adrenocorticotropic hormone or both) and clinical remission, EEG normalization or long-term seizure control. Neurodevelopmental outcome was poor despite good seizure control in the infantile spasm group. This regional study reinforces the relative association of seizures and Down syndrome. A prospective study including a national/international registry with emphasis on developmental assessment and long-term follow up is warranted.

  10. EEG for children with complex febrile seizures.

    Science.gov (United States)

    Shah, Pankaj B; James, Saji; Elayaraja, S

    2015-12-08

    This is an updated version of original Cochrane review published in Issue 1, 2014.Febrile seizures can be classified as simple or complex. Complex febrile seizures are associated with fever that lasts longer than 15 minutes, occur more than once within 24 hours and are confined to one side of the child's body. It is common in some countries for doctors to recommend an electroencephalograph (EEG) for children with complex febrile seizures. A limited evidence base is available to support the use of EEG and its timing after complex febrile seizures among children. To assess the use of EEG and its timing after complex febrile seizures in children younger than five years of age. For the latest update of this review, we searched the Cochrane Epilepsy Group Specialized Register (6 July 2015), the Cochrane Central Register of Controlled Trials (CENTRAL, 2005, Issue 6), MEDLINE (6 July 2015) and ClinicalTrials.gov (6 July 2015). We applied no language restrictions. All randomised controlled trials (RCTs) that examined the utility of an EEG and its timing after complex febrile seizures in children. Review authors selected and retrieved the articles and independently assessed which articles should be included. We resolved disagreements by discussion and by consultation with the Cochrane Epilepsy Group. We applied standard methodological procedures expected by Cochrane. Of 37 potentially eligible studies, no RCTs met the inclusion criteria. We found no RCTs as evidence to support or refute the use of EEG and its timing after complex febrile seizures among children. An RCT can be planned in such a way that participants are randomly assigned to the EEG group and to the non-EEG group with sufficient sample size. Since the last version of this review, we found no new studies.

  11. Computational methods for data evaluation and assimilation

    CERN Document Server

    Cacuci, Dan Gabriel

    2013-01-01

    Data evaluation and data combination require the use of a wide range of probability theory concepts and tools, from deductive statistics mainly concerning frequencies and sample tallies to inductive inference for assimilating non-frequency data and a priori knowledge. Computational Methods for Data Evaluation and Assimilation presents interdisciplinary methods for integrating experimental and computational information. This self-contained book shows how the methods can be applied in many scientific and engineering areas. After presenting the fundamentals underlying the evaluation of experiment

  12. Applications of Constituent Data Assimilation Systems

    Science.gov (United States)

    Rood, Richard B.; Stajner, Ivanka

    1999-01-01

    Organizations in Europe, Australia, and the United States have recently broadened constituent assimilation activities beyond that water vapor, which has been assimilated for years in the numerical weather prediction community. Many of these activities have focused on ozone, with some efforts focused on the entire suite of reactive constituents that control the ozone distribution. This talk will draw from results from the near real-time ozone data assimilation system being run by NASA's Data Assimilation Office. This system utilizes ozone observations from both the TOMS and the SBUV instrument to generate global synoptic maps of ozone. The initial application of this product is to provide ozone fields to assist in the atmospheric corrections' that are necessary for the retrieval of information from other NASA instruments. The validation of the ozone assimilation system shows that the assimilated product agrees well with independent HALOE and ozonesonde observations. This suggests that the product is of sufficient quality to be extended to other applications. This talk will enumerate these other applications and present initial results from exploratory research. The applications being considered include estimates of tropospheric ozone, provision of ozone fields for interactive retrievals, use of analysis increments from the assimilation to evaluate model performance, and development of long-term consistent three-dimensional global ozone fields. The results from the exploratory studies are promising, and help demonstrate how assumptions made in the p development of the ozone assimilation impact the other applications. For instance, RMS errors in the current product are large near the tropopause, which is sensitive to the specification of vertical correlation functions, which in turns impacts the amount of ozone analyzed to be in the troposphere. How these sensitivities impact the different applications will also be discussed.

  13. Variational Data Assimilation in Shelf Circulation Models

    Science.gov (United States)

    2010-01-01

    circulation over shelf and in the adjacent interior ocean energized by coastal flows (a coastal transition zone, CTZ ). - Testing this data assimilation...2005c, Springer et al., 2009), jets in the CTZ (Koch et al., 2010), and internal tides in combination coastal upwelling (Kurapov et al., 2003, 2010a...the Oregon shelf and CTZ extending between 41-47N and 124-129W (Figure 1). In preparation to assimilation tests, a 3 km resolution ROMS model has

  14. Wage and occupational assimilation by skill level

    OpenAIRE

    Alcobendas, Miguel Angel; Rodríguez-Planas, Núria; Vegas, Raquel

    2012-01-01

    While much of the literature on immigrants' assimilation has focused on countries with a large tradition of receiving immigrants and with flexible labor markets, very little is known on how immigrants adjust to other types of host economies. With its severe dual labor market, and an unprecedented immigration boom, Spain presents a quite unique experience to analyze immigrations' assimilation process. Using alternative datasets and methodologies, this paper provides evidence of a differential ...

  15. Employment Assimilation of Immigrants in the Netherlands

    OpenAIRE

    Zorlu, Aslan; Hartog, Joop

    2008-01-01

    This discussion Paper led to a publication in International Journal of Population Research , Vol. 2012, article ID 634276. Using two Dutch labour force surveys, employment assimilation of immigrants is examined. We observe marked differences between immigrants by source country. Non-western immigrants never reach parity with native Dutch. Even second generation immigrants never fully catch up. Caribbean immigrants, who share a colonial history with the Dutch, assimilate relatively quick compa...

  16. Migration, Friendship Ties and Cultural Assimilation

    OpenAIRE

    Facchini, Giovanni; Patacchini, Eleonora; Steinhardt, Max F.

    2014-01-01

    In this paper we contribute to the analysis of the assimilation process of migrants by analyzing the extent to which friendship with natives can be seen as a measure of cultural assimilation and investigating the formation of social ties in the host country. Using novel information from the German Socio-Economic Panel, we find that migrants with a German friend are more similar to natives than those without a local companion along several important dimensions, including concerns about the eco...

  17. Assessing the risk of subsequent tonic-clonic seizures in patients with a history of simple or complex partial seizures.

    Science.gov (United States)

    Rogers, Jennifer K; Hutton, Jane; Marson, Anthony G; Chadwick, David W

    2012-08-01

    Patients who present with only simple or complex partial seizures have a poorly documented prognosis. Treatment may be advocated to prevent future secondary generalised seizures, reduce the frequency of further simple or complex partial seizures or a combination of both. A full statistical analysis on 1334 patients was carried out. The outcomes measured were post-randomisation times to first seizure of any type and first tonic-clonic seizure. Methodology was adopted that accounted for individuals' underlying pre-randomisation seizure counts and allowed for the possibility that there may be a proportion of the sample that will not experience post-randomisation seizure recurrence. 103 subjects randomised to the MESS (Multicentre Study of Early Epilepsy and Single Seizures) study had only partial seizures at randomisation. Only 17 of these had a tonic-clonic seizure during follow-up. The presence of an abnormal EEG at randomisation influenced this risk: an estimated 23% of those with EEG abnormality were at risk of tonic-clonic seizures during follow-up compared with 16% of those with a normal EEG. The group did, however, continue to have partial seizures during follow-up, and modelling showed that the impact of treatment on these seizures was significantly less than the effects of treatment on the frequency of tonic-clonic seizures in those patients with such pre-randomisation seizures. Patients presenting with a history of only partial seizures are at low risk of subsequent tonic-clonic seizures in the period of time to which therapeutic decisions are relevant. The effects of the antiepileptic drugs used in the MESS study are greater for tonic-clonic seizures than they are for partial seizures.

  18. An Emergency Medicine-Focused Review of Seizure Mimics.

    Science.gov (United States)

    Webb, James; Long, Brit; Koyfman, Alex

    2017-05-01

    Seizures result in a change in motor, sensory, and behavioral symptoms caused by abnormal neurologic electrical activity. The symptoms share similar presentations of several other conditions, leading to difficulties in diagnosis and frequent improper management. This review evaluates adult patients with suspected seizure, signs and symptoms of seizure, mimics of seizure, and an approach to management of seizure mimics. A seizure is caused by abnormal neurologic electrical activity resulting in altered motor, sensory, and behavioral symptoms. Other conditions may present similarly, causing a challenge in diagnosis. These conditions include syncope, psychogenic nonepileptic seizures, stroke or transient ischemic attack, sleep disorders, movement disorders, and migraines. Diagnosis of seizures in the emergency department (ED) is often clinical. Differentiation between seizures and other conditions can be difficult. Laboratories and imaging provide little benefit in definitive diagnosis in the emergency setting. For patients that have an apparent seizure, resuscitation and management is precedent while identifying any provoking factors and treatment of those factors. For adults recovering from suspected seizure, the combination of a focused history, physical examination, and additional studies can provide assistance in diagnosis. Patients with an apparent seizure should be resuscitated with identification of provoking factors. Many conditions can mimic seizures. A focused history, physical examination, and additional studies will assist in differentiating seizures from mimics. Published by Elsevier Inc.

  19. Non-invasive imaging of epileptic seizures in vivo using photoacoustic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qizhi; Carney, Paul R; Yuan Zhen; Jiang Huabei [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States); Liu Zhao [Department of Pediatrics, Division of Pediatric Neurology, University of Florida, Gainesville, FL 32610 (United States); Chen Huanxin; Roper, Steven N [Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0265 (United States)], E-mail: hjiang@bme.ufl.edu

    2008-04-07

    Non-invasive laser-induced photoacoustic tomography (PAT) is an emerging imaging modality that has the potential to image the dynamic function of the brain due to its unique ability of imaging biological tissues with high optical contrast and ultrasound resolution. Here we report the first application of our finite-element-based PAT for imaging of epileptic seizures in an animal model. In vivo photoacoustic images were obtained in rats with focal seizures induced by microinjection of bicuculline, a GABA{sub A} antagonist, into the neocortex. The seizure focus was accurately localized by PAT as confirmed with gold-standard electroencephalogram (EEG). Compared to the existing neuroimaging modalities, PAT not only has the unprecedented advantage of high spatial and temporal resolution in a single imaging modality, but also is portable and low in cost, making it possible to bring brain imaging to the bedside.

  20. Modeling and analyzing non-seizure EEG data for patients with epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Lawkins, W.F.; Clapp, N.E. Jr.; Daw, C.S.; Hively, L.M.; Protopopescu, V. [Oak Ridge National Lab., TN (United States); Eisenstadt, M.L. [Knoxville Neurology Clinic, Knoxville, TN (United States)

    1996-05-01

    We present nonlinear analysis of non-seizure electroencephalogram (EEG) time series data from four epileptic patients. A non-seizure state is a period that is free of any part of an epileptic seizure, including the transition to a fully developed episode. EEG measurements are typically contaminated with a large amount of non- neurophysiological source information, generally called artifact, which arises, for example, from eye movement, muscle tension, and physical motion. The first objective of this study is to gain some insight into how much variability in analysis results to be expected from patients having similar clinical characteristics. The second objective is to investigate the impact of eye movement on the analysis results. A special feature presented here is the introduction and testing of a filter for eye movement artifact. The third objective is to determine if neurophysiological activity as viewed from two adjacent channels appears dynamically to be the same.

  1. Comparing hybrid data assimilation methods on the Lorenz 1963 model with increasing non-linearity

    Directory of Open Access Journals (Sweden)

    Michael Goodliff

    2015-05-01

    Full Text Available We systematically compare the performance of ETKF-4DVAR, 4DVAR-BEN and 4DENVAR with respect to two traditional methods (4DVAR and ETKF and an ensemble transform Kalman smoother (ETKS on the Lorenz 1963 model. We specifically investigated this performance with increasing non-linearity and using a quasi-static variational assimilation algorithm as a comparison. Using the analysis root mean square error (RMSE as a metric, these methods have been compared considering (1 assimilation window length and observation interval size and (2 ensemble size to investigate the influence of hybrid background error covariance matrices and non-linearity on the performance of the methods. For short assimilation windows with close to linear dynamics, it has been shown that all hybrid methods show an improvement in RMSE compared to the traditional methods. For long assimilation window lengths in which non-linear dynamics are substantial, the variational framework can have difficulties finding the global minimum of the cost function, so we explore a quasi-static variational assimilation (QSVA framework. Of the hybrid methods, it is seen that under certain parameters, hybrid methods which do not use a climatological background error covariance do not need QSVA to perform accurately. Generally, results show that the ETKS and hybrid methods that do not use a climatological background error covariance matrix with QSVA outperform all other methods due to the full flow dependency of the background error covariance matrix which also allows for the most non-linearity.

  2. Application of Bred Vectors To Data Assimilation

    Science.gov (United States)

    Corazza, M.; Kalnay, E.; Patil, Dj

    We introduced a statistic, the BV-dimension, to measure the effective local finite-time dimensionality of the atmosphere. We show that this dimension is often quite low, and suggest that this finding has important implications for data assimilation and the accuracy of weather forecasting (Patil et al, 2001). The original database for this study was the forecasts of the NCEP global ensemble forecasting system. The initial differences between the control forecast and the per- turbed forecasts are called bred vectors. The control and perturbed initial conditions valid at time t=n(t are evolved using the forecast model until time t=(n+1) (t. The differences between the perturbed and the control forecasts are scaled down to their initial amplitude, and constitute the bred vectors valid at (n+1) (t. Their growth rate is typically about 1.5/day. The bred vectors are similar by construction to leading Lya- punov vectors except that they have small but finite amplitude, and they are valid at finite times. The original NCEP ensemble data set has 5 independent bred vectors. We define a local bred vector at each grid point by choosing the 5 by 5 grid points centered at the grid point (a region of about 1100km by 1100km), and using the north-south and east- west velocity components at 500mb pressure level to form a 50 dimensional column vector. Since we have k=5 global bred vectors, we also have k local bred vectors at each grid point. We estimate the effective dimensionality of the subspace spanned by the local bred vectors by performing a singular value decomposition (EOF analysis). The k local bred vector columns form a 50xk matrix M. The singular values s(i) of M measure the extent to which the k column unit vectors making up the matrix M point in the direction of v(i). We define the bred vector dimension as BVDIM={Sum[s(i)]}^2/{Sum[s(i)]^2} For example, if 4 out of the 5 vectors lie along v, and one lies along v, the BV- dimension would be BVDIM[sqrt(4), 1, 0

  3. Conceptual Problems in Land Surface Data Assimilation

    Science.gov (United States)

    Reichle, Rolf

    2012-01-01

    A land data assimilation system (LDAS) merges observations (or satellite retrievals) of land surface hydrological conditions, including soil moisture, snow, and terrestrial water storage (TWS), into a numerical model of land surface processes. In theory, the output from such a system is superior to estimates based on the observations or the model alone, thereby enhancing our ability to understand, monitor, and predict key elements of the terrestrial water cycle. In practice, however, several conceptual problems can interfere with realizing the potential improvements from data assimilation. Of particular concern is the frequent mismatch between the assimilated observations and the land surface model variables of interest. The seminar will discuss recent research with the ensemble-based NASA GEOS-S LDAS to address various aspects of this mismatch. These aspects include (i) the assimilation of coarse-scale observations into higher-resolution land surface models, (ii) the partitioning of satellite observations (such as TWS retrievals) into their constituent water cycle components, (iii) the forward modeling of microwave brightness temperatures over land for radiance-based land surface data aSSimilation, and (iv) the selection of the most relevant types of observations for the analysis of a specific water cycle variable (such as root zone soil moisture). At its core, the solution to the above challenges involves the careful construction of an observation operator that maps from the land surface model variables of interest to the space of the assimilated observations.

  4. Clinical characteristics of seizures associated with viral gastroenteritis in children.

    Science.gov (United States)

    Ueda, Hitoshi; Tajiri, Hitoshi; Kimura, Sadami; Etani, Yuri; Hosoi, Gaku; Maruyama, Tomoko; Noma, Haruyoshi; Kusumoto, Yoshio; Takano, Tomoko; Baba, Yoshiko; Nagai, Toshizaburo

    2015-01-01

    We analyzed the clinical features of seizures during gastroenteritis in children by comparing the norovirus and rotavirus pathogen, and the impact of fever, if present, during the seizure episodes. Retrospective analysis was performed on 293 consecutive pediatric patients admitted with viral gastroenteritis to Osaka General Hospital between November 2007 and May 2009. Eighteen patients developed seizures, 12 of whom were positive for norovirus and six for rotavirus, as revealed by antigen detection. Of these 18 seizure patients, eight presented without fever (the aFS group) and 10 presented with febrile episodes (FS group). Seizure patients in the rotavirus group (83%) were more likely to be febrile than those in the norovirus group (58%). Compared with the aFS group, 90% of patients in the FS group presented seizures at an early stage of gastroenteritis. The frequency of clustered seizures in the FS group was considerably higher than that of febrile seizures in general and was also as high as that of "convulsions with mild gastroenteritis (CwG)". All seizure patients, whether febrile or afebrile, presented with generalized tonic clonic seizures (GTCS), complex partial seizures (CPS), or both. Diazepam (DZP) was less effective and carbamazepine (CBZ) was completely effective for the cessation of seizures in the FS group, similar to the drug response observed in CwG. The causative pathogen (norovirus or rotavirus) affected the frequency of febrile episodes during gastroenteritis, but fever had little effect on the clinical features of seizures. However, seizures occurred earlier during gastroenteritis in the FS group. On the whole, the clinical features of febrile seizures during viral gastroenteritis may closely resemble those of "convulsions with mild gastroenteritis" (CwG) than those of febrile seizures in general with respect to the frequency of clustered seizures and the antiepileptic drug responses and may have a pathogenic mechanism distinct from those of

  5. Epileptic Seizure Prediction by a System of Particle Filter Associated with a Neural Network

    Science.gov (United States)

    Liu, Derong; Pang, Zhongyu; Wang, Zhuo

    2009-12-01

    None of the current epileptic seizure prediction methods can widely be accepted, due to their poor consistency in performance. In this work, we have developed a novel approach to analyze intracranial EEG data. The energy of the frequency band of 4-12 Hz is obtained by wavelet transform. A dynamic model is introduced to describe the process and a hidden variable is included. The hidden variable can be considered as indicator of seizure activities. The method of particle filter associated with a neural network is used to calculate the hidden variable. Six patients' intracranial EEG data are used to test our algorithm including 39 hours of ictal EEG with 22 seizures and 70 hours of normal EEG recordings. The minimum least square error algorithm is applied to determine optimal parameters in the model adaptively. The results show that our algorithm can successfully predict 15 out of 16 seizures and the average prediction time is 38.5 minutes before seizure onset. The sensitivity is about 93.75% and the specificity (false prediction rate) is approximately 0.09 FP/h. A random predictor is used to calculate the sensitivity under significance level of 5%. Compared to the random predictor, our method achieved much better performance.

  6. Epileptic Seizure Prediction by a System of Particle Filter Associated with a Neural Network

    Directory of Open Access Journals (Sweden)

    Derong Liu

    2009-01-01

    Full Text Available None of the current epileptic seizure prediction methods can widely be accepted, due to their poor consistency in performance. In this work, we have developed a novel approach to analyze intracranial EEG data. The energy of the frequency band of 4–12 Hz is obtained by wavelet transform. A dynamic model is introduced to describe the process and a hidden variable is included. The hidden variable can be considered as indicator of seizure activities. The method of particle filter associated with a neural network is used to calculate the hidden variable. Six patients' intracranial EEG data are used to test our algorithm including 39 hours of ictal EEG with 22 seizures and 70 hours of normal EEG recordings. The minimum least square error algorithm is applied to determine optimal parameters in the model adaptively. The results show that our algorithm can successfully predict 15 out of 16 seizures and the average prediction time is 38.5 minutes before seizure onset. The sensitivity is about 93.75% and the specificity (false prediction rate is approximately 0.09 FP/h. A random predictor is used to calculate the sensitivity under significance level of 5%. Compared to the random predictor, our method achieved much better performance.

  7. Vagus nerve stimulation for induced spinal cord seizures: insights into seizure cessation.

    Science.gov (United States)

    Tubbs, R Shane; Killingsworth, Cheryl R; Rollins, Dennis L; Smith, William M; Ideker, Raymond E; Wellons, John C; Blount, Jeffrey P; Oakes, W Jerry

    2005-03-01

    Vagus nerve stimulation is known to decrease the frequency, duration, and intensity of some types of intracranial seizures in both humans and animals. Although many theories abound concerning the mechanism for this action, the true cause remains speculative. To potentially elucidate a pathway in which vagus nerve stimulation aborts seizure activity, seizures were initiated not in the cerebral cortex but in the spinal cord and then vagus nerve stimulation was performed. Ten pigs were anesthetized and placed in the lateral position, and a small laminectomy was performed in the lumbar region. Topical penicillin, a known epileptogenic drug to the cerebral cortex and spinal cord, was applied to the dorsal surface of the exposed cord. With the exception of two animals that were used as controls, once seizure activity was discernible via motor convulsion or increased electrical activity the left vagus nerve, which had been previously isolated in the neck, was stimulated. Following multiple stimulations of the vagus nerve and with seizure activity confirmed, the cord was transected in the midthoracic region and vagus nerve stimulation was performed. Vagus nerve stimulation resulted in cessation of spinal cord seizure activity in all (87.5%) but one experimented animal. Transection of the spinal cord superior to the site of seizure induction resulted in the ineffectiveness of vagus nerve stimulation to cause cessation of seizure activity in all study animals. The effects of vagus nerve stimulation on induced spinal cord seizures involve descending spinal pathways. The authors believe that this experiment is the first to demonstrate that spinal cord neuronal hyperactivity can be suppressed by stimulation of a cranial nerve. These data may aid in the development of alternative mechanisms for electrical stimulation in patients with medically intractable seizures. Further studies are now necessary to isolate which specific tracts, nuclei, and neurotransmitters are involved in

  8. Involvement of fast-spiking cells in ictal sequences during spontaneous seizures in rats with chronic temporal lobe epilepsy.

    Science.gov (United States)

    Neumann, Adam R; Raedt, Robrecht; Steenland, Hendrik W; Sprengers, Mathieu; Bzymek, Katarzyna; Navratilova, Zaneta; Mesina, Lilia; Xie, Jeanne; Lapointe, Valerie; Kloosterman, Fabian; Vonck, Kristl; Boon, Paul A J M; Soltesz, Ivan; McNaughton, Bruce L; Luczak, Artur

    2017-09-01

    See Lenck-Santini (doi:10.1093/awx205) for a scientific commentary on this article. Epileptic seizures represent altered neuronal network dynamics, but the temporal evolution and cellular substrates of the neuronal activity patterns associated with spontaneous seizures are not fully understood. We used simultaneous recordings from multiple neurons in the hippocampus and neocortex of rats with chronic temporal lobe epilepsy to demonstrate that subsets of cells discharge in a highly stereotypical sequential pattern during ictal events, and that these stereotypical patterns were reproducible across consecutive seizures. In contrast to the canonical view that principal cell discharges dominate ictal events, the ictal sequences were predominantly composed of fast-spiking, putative inhibitory neurons, which displayed unusually strong coupling to local field potential even before seizures. The temporal evolution of activity was characterized by unique dynamics where the most correlated neuronal pairs before seizure onset displayed the largest increases in correlation strength during the seizures. These results demonstrate the selective involvement of fast spiking interneurons in structured temporal sequences during spontaneous ictal events in hippocampal and neocortical circuits in experimental models of chronic temporal lobe epilepsy. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

  9. Seizures arising from the inferior parietal lobule can show ictal semiology of the second sensory seizure (SII seizure).

    Science.gov (United States)

    Yamamoto, J; Ikeda, A; Matsuhashi, M; Satow, T; Takayama, M; Ohara, S; Matsumoto, R; Mikuni, N; Takahashi, J; Miyamoto, S; Taki, W; Hashimoto, N; Shibasaki, H

    2003-03-01

    A 52-year-old right handed man presented with medically intractable partial seizures consisting of numbness on the left upper back spreading to the left upper as well as lower limbs. Head computed tomography and magnetic resonance imaging showed a round calcified lesion in the depth of the superior ramus of the right sylvian fissure. Ictal electrocorticographic recording with chronically implanted subdural electrodes showed low voltage fast activities starting exclusively from an electrode located on the right inferior parietal lobule. No apparent ictal activities were observed from the depth electrodes inserted in the parietal operculum. Somatosensory evoked potentials of 75 ms to 145 ms latency were recorded from the ictal onset zone, which was 2 cm caudal to the perisylvian area corresponding to the second somatosensory area. Seizures arising from the inferior parietal lobule including the angular and supuramarginal gyri can produce partial seizures whose ictal semiology and scalp electroencephalography are indistinguishable from the ones originating from the second somatosensory area.

  10. Sex Differences in Seizure Types and Symptoms

    Science.gov (United States)

    Carlson, Chad; Dugan, Patricia; Kirsch, Heidi E; Friedman, Daniel

    2014-01-01

    Background Despite the increasing interest in sex differences in disease manifestations and responses to treatment, very few data are available on sex differences in seizure types and semiology. The Epilepsy Phenome/Genome Project (EPGP) is a large-scale, multi-institutional, collaborative study that aims to create a comprehensive repository of detailed clinical information and DNA samples from a large cohort of people with epilepsy. We used this well-characterized cohort to explore differences in seizure types as well as focal seizure symptoms between males and females. Methods We reviewed the EPGP database and identified individuals with generalized epilepsy of unknown etiology (GE) (n=760; female 446, male 314), non-acquired focal epilepsy (NAFE) (n=476; female 245, male 231), or both (n=64; female 33, male 31). Demographic data along with characterization of seizure type and focal seizure semiologies were examined. Results In GE, males reported atonic seizures more frequently than females (6.5% vs. 1.7%; p<0.001). No differences were observed in other generalized seizure types. In NAFE, no sex differences were seen for seizure types with or without alteration of consciousness or progression to secondary generalization. Autonomic (16.4% vs. 26.6%; p=0.005), psychic (26.7% vs. 40.3%; p=0.001), and visual symptoms (10.3% vs. 19.9%; p=0.002) were more frequently reported in females than males. Specifically, of psychic symptoms, more females than males endorsed déjà vu (p=0.001), but not forced thoughts, derealization/depersonalization, jamais vu, or fear. With corrections for multiple comparisons, there were no significant differences in aphasic, motor, somatosensory, gustatory, olfactory, auditory, vertiginous, or ictal headache symptoms between sexes. Conclusions Significant differences between the sexes were observed in the reporting of atonic seizures, which was more common in males with GE, and for autonomic, visual, and psychic symptoms associated with NAFE

  11. Amantadine for the treatment of refractory absence seizures in children.

    Science.gov (United States)

    Perry, M Scott; Bailey, Laurie J; Kotecha, Amy C; Malik, Saleem I; Hernandez, Angel W

    2012-04-01

    Amantadine has demonstrated efficacy in small series for absence and myoclonic type seizures. We examined the efficacy of amantadine for treating refractory absence seizures in a cohort of pediatric patients. We retrospectively reviewed medical records for patients with absence seizures treated with amantadine at Cook Children's Medical Center after January 2007. Abstracted data included sex, age at initiation, concomitant antiepileptic drugs, amantadine dosing, and seizure frequency. Outcomes at 3, 6, and 12 months after initiation were categorized as >90%, ≥50%, or 90% reduction in seizure frequency. Amantadine may constitute an efficacious alternative treatment for refractory absence seizures. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Positron emission tomography in generalized seizures

    Energy Technology Data Exchange (ETDEWEB)

    Theodore, W.H.; Brooks, R.; Margolin, R.; Patronas, N.; Sato, S.; Porter, R.J.; Mansi, L.; Bairamian, D.; DiChiro, G.

    1985-05-01

    The authors used /sup 18/F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to study nine patients with clinical absence or generalized seizures. One patient had only absence seizures, two had only generalized tonic-clonic seizures, and six had both seizure types. Interictal scans in eight failed to reveal focal or lateralized hypometabolism. No apparent abnormalities were noted. Two patients had PET scans after isotope injection during hyperventilation-induced generalized spike-wave discharges. Diffusely increased metabolic rates were found in one compared with an interictal scan, and in another compared with control values. Another patient had FDG injected during absence status: EEG showed generalized spike-wave discharges (during which she was unresponsive) intermixed with slow activity accompanied by confusion. Metabolic rates were decreased, compared with the interictal scan, throughout both cortical and subcortical structures. Interictal PET did not detect specific anatomic regions responsible for absence seizure onset in any patient, but the results of the ictal scans did suggest that pathophysiologic differences exist between absence status and single absence attacks.

  13. The Global Structure of UTLS Ozone in GEOS-5: A Multi-Year Assimilation of EOS Aura Data

    Science.gov (United States)

    Wargan, Krzysztof; Pawson, Steven; Olsen, Mark A.; Witte, Jacquelyn C.; Douglass, Anne R.; Ziemke, Jerald R.; Strahan, Susan E.; Nielsen, J. Eric

    2015-01-01

    Eight years of ozone measurements retrieved from the Ozone Monitoring Instrument (OMI) and the Microwave Limb Sounder, both on the EOS Aura satellite, have been assimilated into the Goddard Earth Observing System version 5 (GEOS-5) data assimilation system. This study thoroughly evaluates this assimilated product, highlighting its potential for science. The impact of observations on the GEOS-5 system is explored by examining the spatial distribution of the observation-minus-forecast statistics. Independent data are used for product validation. The correlation coefficient of the lower-stratospheric ozone column with ozonesondes is 0.99 and the bias is 0.5%, indicating the success of the assimilation in reproducing the ozone variability in that layer. The upper-tropospheric assimilated ozone column is about 10% lower than the ozonesonde column but the correlation is still high (0.87). The assimilation is shown to realistically capture the sharp cross-tropopause gradient in ozone mixing ratio. Occurrence of transport-driven low ozone laminae in the assimilation system is similar to that obtained from the High Resolution Dynamics Limb Sounder (HIRDLS) above the 400 K potential temperature surface but the assimilation produces fewer laminae than seen by HIRDLS below that surface. Although the assimilation produces 5 - 8 fewer occurrences per day (up to approximately 20%) during the three years of HIRDLS data, the interannual variability is captured correctly. This data-driven assimilated product is complementary to ozone fields generated from chemistry and transport models. Applications include study of the radiative forcing by ozone and tracer transport near the tropopause.

  14. Key aspects of stratospheric tracer modeling using assimilated winds

    Directory of Open Access Journals (Sweden)

    B. Bregman

    2006-01-01

    Full Text Available This study describes key aspects of global chemistry-transport models and their impact on stratospheric tracer transport. We concentrate on global models that use assimilated winds from numerical weather predictions, but the results also apply to tracer transport in general circulation models. We examined grid resolution, numerical diffusion, air parcel dispersion, the wind or mass flux update frequency, and time interpolation. The evaluation is performed with assimilated meteorology from the "operational analyses or operational data" (OD from the European Centre for Medium-Range Weather Forecasts (ECMWF. We also show the effect of the mass flux update frequency using the ECMWF 40-year re-analyses (ERA40. We applied the three-dimensional chemistry-transport Tracer Model version 5 (TM5 and a trajectory model and performed several diagnoses focusing on different transport regimes. Covering different time and spatial scales, we examined (1 polar vortex dynamics during the Arctic winter, (2 the large-scale stratospheric meridional circulation, and (3 air parcel dispersion in the tropical lower stratosphere. Tracer distributions inside the Arctic polar vortex show considerably worse agreement with observations when the model grid resolution in the polar region is reduced to avoid numerical instability. The results are sensitive to the diffusivity of the advection. Nevertheless, the use of a computational cheaper but diffusive advection scheme is feasible for tracer transport when the horizontal grid resolution is equal or smaller than 1 degree. The use of time interpolated winds improves the tracer distributions, particularly in the middle and upper stratosphere. Considerable improvement is found both in the large-scale tracer distribution and in the polar regions when the update frequency of the assimilated winds is increased from 6 to 3 h. It considerably reduces the vertical dispersion of air parcels in the tropical lower stratosphere. Strong

  15. Estimating Model Evidence Using Data Assimilation

    Science.gov (United States)

    Carrassi, Alberto; Bocquet, Marc; Hannart, Alexis; Ghil, Michael

    2017-04-01

    We review the field of data assimilation (DA) from a Bayesian perspective and show that, in addition to its by now common application to state estimation, DA may be used for model selection. An important special case of the latter is the discrimination between a factual model - which corresponds, to the best of the modeller's knowledge, to the situation in the actual world in which a sequence of events has occurred-and a counterfactual model, in which a particular forcing or process might be absent or just quantitatively different from the actual world. Three different ensemble-DA methods are reviewed for this purpose: the ensemble Kalman filter (EnKF), the ensemble four-dimensional variational smoother (En-4D-Var), and the iterative ensemble Kalman smoother (IEnKS). An original contextual formulation of model evidence (CME) is introduced. It is shown how to apply these three methods to compute CME, using the approximated time-dependent probability distribution functions (pdfs) each of them provide in the process of state estimation. The theoretical formulae so derived are applied to two simplified nonlinear and chaotic models: (i) the Lorenz three-variable convection model (L63), and (ii) the Lorenz 40- variable midlatitude atmospheric dynamics model (L95). The numerical results of these three DA-based methods and those of an integration based on importance sampling are compared. It is found that better CME estimates are obtained by using DA, and the IEnKS method appears to be best among the DA methods. Differences among the performance of the three DA-based methods are discussed as a function of model properties. Finally, the methodology is implemented for parameter estimation and for event attribution.

  16. Reanalysis of the Indian summer monsoon: four dimensional data assimilation of AIRS retrievals in a regional data assimilation and modeling framework

    Science.gov (United States)

    Attada, Raju; Parekh, Anant; Chowdary, J. S.; Gnanaseelan, C.

    2017-07-01

    This work is the first attempt to produce a multi-year downscaled regional reanalysis of the Indian summer monsoon (ISM) using the National Centers for Environmental Prediction (NCEP) operational analyses and Atmospheric Infrared Sounder (AIRS) version 5 temperature and moisture retrievals in a regional model. Reanalysis of nine monsoon seasons (2003-2011) are produced in two parallel setups. The first set of experiments simply downscale the original NCEP operational analyses, whilst the second one assimilates the AIRS temperature and moisture profiles. The results show better representation of the key monsoon features such as low level jet, tropical easterly jet, subtropical westerly jet, monsoon trough and the spatial pattern of precipitation when AIRS profiles are assimilated (compared to those without AIRS data assimilation). The distribution of temperature, moisture and meridional gradients of dynamical and thermodynamical fields over the monsoon region are better represented in the reanalysis that assimilates AIRS profiles. The change induced by AIRS data on the moist and thermodynamic conditions results in more realistic rendering of the vertical shear associated with the monsoon, which in turn leads to a proper moisture transport and the moist convective feedback. This feedback benefits the representation of the regional monsoon characteristics, the monsoon dynamics and the moist convective processes on the seasonal time scale. This study emphasizes the use of AIRS soundings for downscaling of ISM representation in a regional reanalysis.

  17. Reanalysis of the Indian summer monsoon: four dimensional data assimilation of AIRS retrievals in a regional data assimilation and modeling framework

    KAUST Repository

    Attada, Raju

    2017-07-04

    This work is the first attempt to produce a multi-year downscaled regional reanalysis of the Indian summer monsoon (ISM) using the National Centers for Environmental Prediction (NCEP) operational analyses and Atmospheric Infrared Sounder (AIRS) version 5 temperature and moisture retrievals in a regional model. Reanalysis of nine monsoon seasons (2003–2011) are produced in two parallel setups. The first set of experiments simply downscale the original NCEP operational analyses, whilst the second one assimilates the AIRS temperature and moisture profiles. The results show better representation of the key monsoon features such as low level jet, tropical easterly jet, subtropical westerly jet, monsoon trough and the spatial pattern of precipitation when AIRS profiles are assimilated (compared to those without AIRS data assimilation). The distribution of temperature, moisture and meridional gradients of dynamical and thermodynamical fields over the monsoon region are better represented in the reanalysis that assimilates AIRS profiles. The change induced by AIRS data on the moist and thermodynamic conditions results in more realistic rendering of the vertical shear associated with the monsoon, which in turn leads to a proper moisture transport and the moist convective feedback. This feedback benefits the representation of the regional monsoon characteristics, the monsoon dynamics and the moist convective processes on the seasonal time scale. This study emphasizes the use of AIRS soundings for downscaling of ISM representation in a regional reanalysis.

  18. Self-control of epileptic seizures by nonpharmacological strategies.

    Science.gov (United States)

    Kotwas, Iliana; McGonigal, Aileen; Trebuchon, Agnès; Bastien-Toniazzo, Mireille; Nagai, Yoko; Bartolomei, Fabrice; Micoulaud-Franchi, Jean-Arthur

    2016-02-01

    Despite the unpredictability of epileptic seizures, many patients report that they can anticipate seizure occurrence. Using certain alert symptoms (i.e., auras, prodromes, precipitant factors), patients can adopt behaviors to avoid injury during and after the seizure or may implement spontaneous cognitive and emotional strategies to try to control the seizure itself. From the patient's view point, potential means of enhancing seizure prediction and developing seizure control supports are seen as very important issues, especially when the epilepsy is drug-resistant. In this review, we first describe how some patients anticipate their seizures and whether this is effective in terms of seizure prediction. Secondly, we examine how these anticipatory elements might help patients to prevent or control their seizures and how the patient's neuropsychological profile, specifically parameters of perceived self-control (PSC) and locus of control (LOC), might impact these strategies and quality of life (QOL). Thirdly, we review the external supports that can help patients to better predict seizures. Finally, we look at nonpharmacological means of increasing perceived self-control and achieving potential reduction of seizure frequency (i.e., stress-based and arousal-based strategies). In the past few years, various approaches for detection and control of seizures have gained greater interest, but more research is needed to confirm a positive effect on seizure frequency as well as on QOL. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Are seizures in the setting of sleep deprivation provoked?

    Science.gov (United States)

    Lawn, Nicholas; Lieblich, Sam; Lee, Judy; Dunne, John

    2014-04-01

    It is generally accepted that sleep deprivation contributes to seizures. However, it is unclear whether a seizure occurring in the setting of sleep deprivation should be considered as provoked or not and whether this is influenced by seizure type and etiology. This information may have an important impact on epilepsy diagnosis and management. We prospectively analyzed the influence of sleep deprivation on the risk of seizure recurrence in patients with first-ever unprovoked seizures and compared the findings with patients with first-ever provoked seizures. Of 1026 patients with first-ever unprovoked seizures, 204 (20%) were associated with sleep deprivation. While the overall likelihood of seizure recurrence was slightly lower in sleep-deprived patients with first-ever seizures (log-rank p=0.03), sleep deprivation was not an independent predictor of seizure recurrence on multivariate analysis. Seizure recurrence following a first-ever unprovoked seizure associated with sleep deprivation was far more likely than for 174 patients with a provoked first-ever seizure (log-rank psleep deprivation should not be regarded as provoked. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. A new model to study sleep deprivation-induced seizure.

    Science.gov (United States)

    Lucey, Brendan P; Leahy, Averi; Rosas, Regine; Shaw, Paul J

    2015-05-01

    A relationship between sleep and seizures is well-described in both humans and rodent animal models; however, the mechanism underlying this relationship is unknown. Using Drosophila melanogaster mutants with seizure phenotypes, we demonstrate that seizure activity can be modified by sleep deprivation. Seizure activity was evaluated in an adult bang-sensitive seizure mutant, stress sensitive B (sesB(9ed4)), and in an adult temperature sensitive seizure mutant seizure (sei(ts1)) under baseline and following 12 h of sleep deprivation. The long-term effect of sleep deprivation on young, immature sesB(9ed4) flies was also assessed. Laboratory. Drosophila melanogaster. Sleep deprivation. Sleep deprivation increased seizure susceptibility in adult sesB(9ed4)/+ and sei(ts1) mutant flies. Sleep deprivation also increased seizure susceptibility when sesB was disrupted using RNAi. The effect of sleep deprivation on seizure activity was reduced when sesB(9ed4)/+ flies were given the anti-seizure drug, valproic acid. In contrast to adult flies, sleep deprivation during early fly development resulted in chronic seizure susceptibility when sesB(9ed4)/+ became adults. These findings show that Drosophila is a model organism for investigating the relationship between sleep and seizure activity. © 2015 Associated Professional Sleep Societies, LLC.

  1. Phenytoin versus valproate monotherapy for partial onset seizures and generalised onset tonic-clonic seizures.

    Science.gov (United States)

    Nolan, Sarah J; Marson, Anthony G; Pulman, Jennifer; Tudur Smith, Catrin

    2013-08-23

    This is an updated version of the previously published Cochrane review (Issue 4, 2009)Worldwide, phenytoin and valproate are commonly used antiepileptic drugs. It is generally believed that phenytoin is more effective for partial onset seizures, and that valproate is more effective for generalised onset tonic-clonic seizures with or without other generalised seizure types. To review the best evidence comparing phenytoin and valproate when used as monotherapy in individuals with partial onset seizures or generalised onset tonic-clonic seizures with or without other generalised seizure types. We searched the Cochrane Epilepsy Group's Specialised Register (19 February 2013), the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, The Cochrane Library, January 2013), MEDLINE (1946 to 18 February 2013), SCOPUS (19 February 2013), ClinicalTrials.gov (19 February 2013), and WHO International Clinical Trials Registry Platform ICTRP (19 February 2013). We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field. Randomised controlled trials in children or adults with partial onset seizures or generalised onset tonic-clonic seizures with a comparison of valproate monotherapy versus phenytoin monotherapy. This was an individual patient data review. Outcomes were time to (a) treatment withdrawal (b) 12-month remission (c) six-month remission and (d) first seizure post randomisation. Cox proportional hazards regression models were used to obtain study-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs) with the generic inverse variance method used to obtain the overall pooled HR and 95% CI. Individual patient data were available for 669 individuals out of 1119 eligible individuals from five out of 11 trials, 60% of the potential data. Results apply to generalised tonic-clonic seizures, but not absence or myoclonus seizure types. For remission outcomes, HR > 1 indicates an

  2. THE SOCIAL CONTEXT OF ASSIMILATION: TESTING IMPLICATIONS OF SEGMENTED ASSIMILATION THEORY*

    Science.gov (United States)

    Xie, Yu; Greenman, Emily

    2011-01-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between social context and assimilation on immigrant children's well-being. We then test the hypotheses using data from the National Longitudinal Study of Adolescent Health. Our empirical analyses yield two main findings. First, for immigrant adolescents living in non-poverty neighborhoods, we find assimilation to be positively associated with educational achievement and psychological well-being but also positively associated with at-risk behavior. Second, there is little empirical evidence supporting our hypotheses derived from segmented assimilation theory. We interpret these results to mean that future research would be more fruitful focusing on differential processes of assimilation rather than differential consequences of assimilation. PMID:21572546

  3. The social context of assimilation: testing implications of segmented assimilation theory.

    Science.gov (United States)

    Xie, Yu; Greenman, Emily

    2011-05-01

    Segmented assimilation theory has been a popular explanation for the diverse experiences of assimilation among new waves of immigrants and their children. While the theory has been interpreted in many different ways, we emphasize its implications for the important role of social context: both processes and consequences of assimilation should depend on the local social context in which immigrants are embedded. We derive empirically falsifiable hypotheses about the interaction effects between social context and assimilation on immigrant children's well-being. We then test the hypotheses using data from the National Longitudinal Study of Adolescent Health. Our empirical analyses yield two main findings. First, for immigrant adolescents living in non-poverty neighborhoods, we find assimilation to be positively associated with educational achievement and psychological well-being but also positively associated with at-risk behavior. Second, there is little empirical evidence supporting our hypotheses derived from segmented assimilation theory. We interpret these results to mean that future research would be more fruitful focusing on differential processes of assimilation rather than differential consequences of assimilation.

  4. IS ASSIMILATION THEORY DEAD? THE EFFECT OF ASSIMILATION ON ADOLESCENT WELL-BEING.

    Science.gov (United States)

    Greenman, Emily; Xie, Yu

    2008-03-01

    The relationship between assimilation and the well-being of immigrant children has been the focus of debate in the recent sociological literature. Much of this work has questioned whether classical theories of immigrant adaptation, which assumed assimilation to be an integral part of the process of upward mobility for immigrants, are still applicable to today's immigrant children. This study reevaluates the applicability of classical assimilation theory with a comprehensive empirical assessment of the relationship between assimilation and the well-being of Hispanic and Asian immigrant adolescents. Using Add Health data, we examine the effect of different aspects of assimilation on educational achievement, psychological well-being, and at-risk behaviors. We find that the effect of assimilation varies greatly depending on the ethnic group and outcome under consideration, but that it is generally related to both greater academic achievement and more at-risk behavior. We conclude that assimilation theory is still relevant, but suggest an interpretation that emphasizes a process of decreasing differences between groups rather than either detrimental or beneficial effects of assimilation.

  5. Recent advances in land data assimilation at the NASA Global Modeling and Assimilation Office

    Science.gov (United States)

    Research in land surface data assimilation has grown rapidly over the last decade. We provide a brief overview of key research contributions by the NASA Global Modeling and Assimilation Office (GMAO). The GMAO contributions primarily include the continued development and application of the Ensembl...

  6. Gender difference in acquired seizure susceptibility in adult rats after early complex febrile seizures.

    Science.gov (United States)

    Dai, Yun-Jian; Xu, Zheng-Hao; Feng, Bo; Xu, Ceng-Lin; Zhao, Hua-Wei; Wu, Deng-Chang; Hu, Wei-Wei; Chen, Zhong

    2014-12-01

    Gender differences are involved in many neurological disorders including epilepsy. However, little is known about the effect of gender difference on the risk of epilepsy in adults with a specific early pathological state such as complex febrile seizures (FSs) in infancy. Here we used a well-established complex FS model in rats and showed that: (1) the susceptibility to seizures induced by hyperthermia, pentylenetetrazol (PTZ), and maximal electroshock (MES) was similar in male and female rat pups, while males were more susceptible to PTZ- and MES-induced seizures than age-matched females in normal adult rats; (2) adult rats with complex FSs in infancy acquired higher seizure susceptibility than normal rats; importantly, female FS rats were more susceptible to PTZ and MES than male FS rats; and (3) the protein expression of interleukin-1β, an inflammatory factor associated with seizure susceptibility, was higher in adult FS females than in males, which may reflect a gender-difference phenomenon of seizure susceptibility. Our results provide direct evidence that the acquired seizure susceptibility after complex FSs is gender-dependent.

  7. Febrile Seizures and Febrile Seizure Syndromes: An Updated Overview of Old and Current Knowledge

    Science.gov (United States)

    Khair, Abdulhafeez M.; Elmagrabi, Dalal

    2015-01-01

    Febrile seizures are the most common paroxysmal episode during childhood, affecting up to one in 10 children. They are a major cause of emergency facility visits and a source of family distress and anxiety. Their etiology and pathophysiological pathways are being understood better over time; however, there is still more to learn. Genetic predisposition is thought to be a major contributor. Febrile seizures have been historically classified as benign; however, many emerging febrile seizure syndromes behave differently. The way in which human knowledge has evolved over the years in regard to febrile seizures has not been dealt with in depth in the current literature, up to our current knowledge. This review serves as a documentary of how scientists have explored febrile seizures, elaborating on the journey of knowledge as far as etiology, clinical features, approach, and treatment strategies are concerned. Although this review cannot cover all clinical aspects related to febrile seizures at the textbook level, we believe it can function as a quick summary of the past and current sources of knowledge for all varieties of febrile seizure types and syndromes. PMID:26697219

  8. What is a seizure network? Long-range network consequences of focal seizures.

    Science.gov (United States)

    Blumenfeld, Hal

    2014-01-01

    What defines the spatial and temporal boundaries of seizure activity in brain networks? To fully answer this question a precise and quantitative definition of seizures is needed, which unfortunately remains elusive. Nevertheless, it is possible to ask under conditions where clearly divergent patterns of activity occur in large-scale brain networks whether certain activity patterns are part of the seizure while others are not. Here we examine brain network activity during focal limbic seizures, including diverse regions such as the hippocampus, subcortical arousal systems and fronto-parietal association cortex. Based on work from patients and from animal models we describe a characteristic pattern of intense increases in neuronal firing, cerebral blood flow, cerebral blood volume, blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) signals and cerebral metabolic rate of oxygen consumption in the hippocampus during focal limbic seizures. Similar increases are seen in certain closely linked subcortical structures such as the lateral septal nuclei and anterior hypothalamus, which contain inhibitory neurons. In marked contrast, decreases in all of these parameters are seen in the subcortical arousal systems of the upper brainstem and intralaminar thalamus, as well as in the fronto-parietal association cortex. We propose that the seizure proper can be defined as regions showing intense increases, while those areas showing opposite changes are inhibited by the seizure network and constitute long-range network consequences beyond the seizure itself. Importantly, the fronto-parietal cortex shows sleep-like slow wave activity and depressed metabolism under these conditions, associated with impaired consciousness. Understanding which brain networks are directly involved in seizures versus which sustain secondary consequences can provide new insights into the mechanisms of brain dysfunction in epilepsy, hopefully leading to innovative treatment

  9. Green's Function-Based Tsunami Data Assimilation: A Fast Data Assimilation Approach Toward Tsunami Early Warning

    Science.gov (United States)

    Wang, Yuchen; Satake, Kenji; Maeda, Takuto; Gusman, Aditya Riadi

    2017-10-01

    We propose a new tsunami data assimilation approach based on Green's functions to reduce the computation time for tsunami early warning. Green's Function-based Tsunami Data Assimilation (GFTDA) forecasts the waveforms at points of interest (PoIs) by superposition of Green's functions between observation stations and PoIs. Unlike the previous assimilation approach, GFTDA does not require the calculation of the tsunami wavefield for the whole region during the assimilation process, because the Green's functions have been calculated in advance. The forecasted waveforms can be calculated by a simple matrix manipulation. The application to the tsunami waveforms recorded by the bottom pressure gauges of the Cascadia Initiative from the 2012 Haida Gwaii earthquake reveals that GFTDA achieves the same accuracy as the previous assimilation approach while reducing the time required to issue a valid tsunami warning.

  10. Seizures and Praziquantel. A case report

    Directory of Open Access Journals (Sweden)

    Jaime R. Torres R.

    1988-12-01

    Full Text Available A 27 year Old male developed seizures after receiving a single 20 mg/kg dose of praziquantel for the treatment of an intestinal Hymenolepis nana infection. On further clinical and laboratorial evaluations, he was found to suffer from an until then asymptomatic parenchymal brain cysticercosis. Praziquantel must be used with caution in those areas where cysticercosis represents a mayor public health problem. The occurrence of unexpected seizures in an individual being treated with the compound, must prompt clinicians to rule out cysticercosis of the CNS.

  11. Treating seizures and epilepsy with anticoagulants?

    Directory of Open Access Journals (Sweden)

    Nicola eMaggio

    2013-03-01

    Full Text Available Thrombin is a serine protease playing an essential role in the blood coagulation cascade. Recent work, however, has identified a novel role for thrombin-mediated signaling pathways in the central nervous system. Binding of thrombin to protease-activated receptors (PARs in the brain appears to have multiple actions affecting both health and disease. Specifically, thrombin has been shown to lead to the onset of seizures via PAR-1 activation. In this perspective article, we review the putative mechanisms by which thrombin causes seizures and epilepsy. We propose a potential role of PAR-1 antagonists and novel thrombin inhibitors as new, possible antiepileptic drugs.

  12. Seizures after intravenous tramadol given as premedication

    Directory of Open Access Journals (Sweden)

    Lalit Kumar Raiger

    2012-01-01

    Full Text Available A 35-year-old, 50-kg female with a history of epilepsy was scheduled for elective breast surgery (fibroadenoma under general anaesthesia. She was given glycopyrrolate 0.2 mg, ondansetron 4 mg and tramadol 100 mg i.v. as premedication. Within 5 min, she had an acute episode of generalised tonic-clonic seizure that was successfully treated with 75 mg thiopentone i.v. and after 30 min, she was given general anaesthesia with endotracheal intubation. Surgery, intra-operative period, extubation and post-operative period were uneventful. We conclude that tramadol may provoke seizures in patients with epilepsy even within the recommended dose range.

  13. Snow multivariable data assimilation for hydrological predictions in Alpine sites

    Science.gov (United States)

    Piazzi, Gaia; Thirel, Guillaume; Campo, Lorenzo; Gabellani, Simone; Stevenin, Hervè

    2017-04-01

    Snowpack dynamics (snow accumulation and ablation) strongly impacts on hydrological processes in Alpine areas. During the winter season the presence of snow cover (snow accumulation) reduces the drainage in the basin with a resulting lower watershed time of concentration in case of possible rainfall events. Moreover, the release of the significant water volume stored in winter (snowmelt) considerably contributes to the total discharge during the melting period. Therefore when modeling hydrological processes in snow-dominated catchments the quality of predictions deeply depends on how the model succeeds in catching snowpack dynamics. The integration of a hydrological model with a snow module allows improving predictions of river discharges. Besides the well-known modeling limitations (uncertainty in parameterizations; possible errors affecting both meteorological forcing data and initial conditions; approximations in boundary conditions), there are physical factors that make an exhaustive reconstruction of snow dynamics complicated: snow intermittence in space and time, stratification and slow phenomena like metamorphism processes, uncertainty in snowfall evaluation, wind transportation, etc. Data Assimilation (DA) techniques provide an objective methodology to combine several independent snow-related data sources (model simulations, ground-based measurements and remote sensed observations) in order to obtain the most likely estimate of snowpack state. This study presents SMASH (Snow Multidata Assimilation System for Hydrology), a multi-layer snow dynamic model strengthened by a multivariable DA framework for hydrological purposes. The model is physically based on mass and energy balances and can be used to reproduce the main physical processes occurring within the snowpack: accumulation, density dynamics, melting, sublimation, radiative balance, heat and mass exchanges. The model is driven by observed forcing meteorological data (air temperature, wind velocity

  14. Functional brain connectivity from EEG in epilepsy: seizure prediction and epileptogenic focus localization.

    Science.gov (United States)

    van Mierlo, Pieter; Papadopoulou, Margarita; Carrette, Evelien; Boon, Paul; Vandenberghe, Stefaan; Vonck, Kristl; Marinazzo, Daniele

    2014-10-01

    Today, neuroimaging techniques are frequently used to investigate the integration of functionally specialized brain regions in a network. Functional connectivity, which quantifies the statistical dependencies among the dynamics of simultaneously recorded signals, allows to infer the dynamical interactions of segregated brain regions. In this review we discuss how the functional connectivity patterns obtained from intracranial and scalp electroencephalographic (EEG) recordings reveal information about the dynamics of the epileptic brain and can be used to predict upcoming seizures and to localize the seizure onset zone. The added value of extracting information that is not visibly identifiable in the EEG data using functional connectivity analysis is stressed. Despite the fact that many studies have showed promising results, we must conclude that functional connectivity analysis has not made its way into clinical practice yet. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. A systematic review of suggestive seizure induction for the diagnosis of psychogenic nonepileptic seizures.

    Science.gov (United States)

    Popkirov, Stoyan; Grönheit, Wenke; Wellmer, Jörg

    2015-09-01

    Suggestive seizure induction is a widely used method for diagnosing psychogenic nonepileptic seizures (PNES). Despite seven decades of multidisciplinary research, however, there is still no unified protocol, no definitive agreement on the ethical framework and no consensus on diagnostic utility. This systematic review surveys the evidence at hand and addresses clinically relevant aspects of suggestive seizure induction. In addition to its use for facilitating the diagnostic process, its mechanism of action and utility in elucidating the psychopathology of PNES will be discussed. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  16. Do recurrent seizure-related head injuries affect seizures in people with epilepsy?

    OpenAIRE

    Friedman, David E.; Chiang, Sharon; Tobias, Ronnie S.

    2012-01-01

    Seizure-related head injuries (SRHIs) are among the most commonly encountered injuries in people with epilepsy (PWE). Whether head injury has an effect on preexisting epilepsy is not known. The purpose of this study was to systematically assess for any possible effects of SRHIs on seizure frequency and seizure semiology over a 2-year period. We identified 204 patients who have been followed at the Baylor Comprehensive Epilepsy Center from 2008 to 2010. SRHI occurred in 18.1% of the cohort. Mo...

  17. Hyperkinetic motor seizures: a common semiology generated by two different cortical seizure origins.

    Science.gov (United States)

    Vaugier, Lisa; McGonigal, Aileen; Lagarde, Stanislas; Trébuchon, Agnes; Szurhaj, William; Derambure, Philippe; Bartolomei, Fabrice

    2017-09-01

    We report a 37-year-old, right-handed patient with drug-resistant focal epilepsy whose seizures were characterized by explosive hyperkinetic behaviour. Video-SEEG revealed bifocal organization of epilepsy with two distinct cortical origins of seizures: the right temporal pole and left temporal lateral and perisylvian cortex. Irrespective of the cortical pattern of seizure onset, the hyperkinetic semiology was extremely similar. This supports a major role for "final common pathway" subcortical circuits in the genesis of the hyperkinetic semiology in this patient.

  18. Genetics Home Reference: genetic epilepsy with febrile seizures plus

    Science.gov (United States)

    ... Health Conditions Genetic epilepsy with febrile seizures plus Genetic epilepsy with febrile seizures plus Printable PDF Open ... 9):1426-9. Citation on PubMed More from Genetics Home Reference Bulletins January is National Birth Defects ...

  19. Experimenting with the GMAO 4D Data Assimilation

    Science.gov (United States)

    Todling, R.; El Akkraoui, A.; Errico, R. M.; Guo, J.; Kim, J.; Kliest, D.; Parrish, D. F.; Suarez, M.; Trayanov, A.; Tremolet, Yannick; hide

    2012-01-01

    The Global Modeling and Assimilation Office (GMAO) has been working to promote its prototype four-dimensional variational (4DVAR) system to a version that can be exercised at operationally desirable configurations. Beyond a general circulation model (GeM) and an analysis system, traditional 4DV AR requires availability of tangent linear (TL) and adjoint (AD) models of the corresponding GeM. The GMAO prototype 4DVAR uses the finite-volume-based GEOS GeM and the Grid-point Statistical Interpolation (GSI) system for the first two, and TL and AD models derived ITom an early version of the finite-volume hydrodynamics that is scientifically equivalent to the present GEOS nonlinear GeM but computationally rather outdated. Specifically, the TL and AD models hydrodynamics uses a simple (I-dimensional) latitudinal MPI domain decomposition, which has consequent low scalability and prevents the prototype 4DV AR ITom being used in realistic applications. In the near future, GMAO will be upgrading its operational GEOS GCM (and assimilation system) to use a cubed-sphere-based hydrodynamics. This versions of the dynamics scales to thousands of processes and has led to a decision to re-derive the TL and AD models for this more modern dynamics, thus taking advantage of a two-dimensional MPI decomposition and improved scalability properties. With the aid of the Transformation of Algorithms in FORTRAN (l'AF) automatic adjoint generation tool and some hand-coding, a version of the cubed-sphere-based TL and AD models, with a simplified vertical diffusion scheme, is now available, enabling multiple configurations of standard implementations of 4DV AR in GEOS. Concurrent to this development, collaboration with the National Centers for Environmental Prediction (NCEP) and the Earth System Research Laboratory (ESRL) has allowed GMAO to implement a hybrid-ensemble capability within the GEOS data assimilation system. Both 3Dand 4D-ensemble capabilities are presently available thus allowing

  20. Pharmacotherapy for neonatal seizures: current knowledge and future perspectives

    OpenAIRE

    Donovan, Maria D.; Griffin, Brendan T; Kharoshankaya, Liudmila; Cryan, John F.; Boylan, Geraldine B.

    2016-01-01

    Seizures are the most common neurological emergencies in the neonatal period and are associated with poor neurodevelopmental outcomes. Seizures affect up to five per 1000 term births and population-based studies suggest that they occur even more frequently in premature infants. Seizures are a sign of an underlying cerebral pathology, the most common of which is hypoxic-ischaemic encephalopathy in term infants. Due to a growing body of evidence that seizures exacerbate cerebral injury, effecti...

  1. Multicenter clinical assessment of improved wearable multimodal convulsive seizure detectors.

    Science.gov (United States)

    Onorati, Francesco; Regalia, Giulia; Caborni, Chiara; Migliorini, Matteo; Bender, Daniel; Poh, Ming-Zher; Frazier, Cherise; Kovitch Thropp, Eliana; Mynatt, Elizabeth D; Bidwell, Jonathan; Mai, Roberto; LaFrance, W Curt; Blum, Andrew S; Friedman, Daniel; Loddenkemper, Tobias; Mohammadpour-Touserkani, Fatemeh; Reinsberger, Claus; Tognetti, Simone; Picard, Rosalind W

    2017-11-01

    New devices are needed for monitoring seizures, especially those associated with sudden unexpected death in epilepsy (SUDEP). They must be unobtrusive and automated, and provide false alarm rates (FARs) bearable in everyday life. This study quantifies the performance of new multimodal wrist-worn convulsive seizure detectors. Hand-annotated video-electroencephalographic seizure events were collected from 69 patients at six clinical sites. Three different wristbands were used to record electrodermal activity (EDA) and accelerometer (ACM) signals, obtaining 5,928 h of data, including 55 convulsive epileptic seizures (six focal tonic-clonic seizures and 49 focal to bilateral tonic-clonic seizures) from 22 patients. Recordings were analyzed offline to train and test two new machine learning classifiers and a published classifier based on EDA and ACM. Moreover, wristband data were analyzed to estimate seizure-motion duration and autonomic responses. The two novel classifiers consistently outperformed the previous detector. The most efficient (Classifier III) yielded sensitivity of 94.55%, and an FAR of 0.2 events/day. No nocturnal seizures were missed. Most patients had seizure frequency. When increasing the sensitivity to 100% (no missed seizures), the FAR is up to 13 times lower than with the previous detector. Furthermore, all detections occurred before the seizure ended, providing reasonable latency (median = 29.3 s, range = 14.8-151 s). Automatically estimated seizure durations were correlated with true durations, enabling reliable annotations. Finally, EDA measurements confirmed the presence of postictal autonomic dysfunction, exhibiting a significant rise in 73% of the convulsive seizures. The proposed multimodal wrist-worn convulsive seizure detectors provide seizure counts that are more accurate than previous automated detectors and typical patient self-reports, while maintaining a tolerable FAR for ambulatory monitoring. Furthermore, the multimodal system

  2. Pitfall of bispectral index during intraoperative seizure -a case report-

    OpenAIRE

    Kim, Hyungdong; Kim, Sae Young

    2013-01-01

    We report a case of a 42-year-old male who developed generalized tonic-clonic seizure with sudden, brief decrease in bispectral index (BIS) value while undergoing emergency kidney transplantation. Few reports have been made on intraoperative pitfall of BIS value associated with seizure. This case report suggests seizure should be taken into account as a reason for such brief fall of BIS, especially while under general anesthesia or in other specific cases in which clinical signs of seizure ar...

  3. Epileptic seizure prediction based on a bivariate spectral power methodology.

    Science.gov (United States)

    Bandarabadi, Mojtaba; Teixeira, Cesar A; Direito, Bruno; Dourado, Antonio

    2012-01-01

    The spectral power of 5 frequently considered frequency bands (Alpha, Beta, Gamma, Theta and Delta) for 6 EEG channels is computed and then all the possible pairwise combinations among the 30 features set, are used to create a 435 dimensional feature space. Two new feature selection methods are introduced to choose the best candidate features among those and to reduce the dimensionality of this feature space. The selected features are then fed to Support Vector Machines (SVMs) that classify the cerebral state in preictal and non-preictal classes. The outputs of the SVM are regularized using a method that accounts for the classification dynamics of the preictal class, also known as "Firing Power" method. The results obtained using our feature selection approaches are compared with the ones obtained using minimum Redundancy Maximum Relevance (mRMR) feature selection method. The results in a group of 12 patients of the EPILEPSIAE database, containing 46 seizures and 787 hours multichannel recording for out-of-sample data, indicate the efficiency of the bivariate approach as well as the two new feature selection methods. The best results presented sensitivity of 76.09% (35 of 46 seizures predicted) and a false prediction rate of 0.15(-1).

  4. CATS Version 2 Aerosol Feature Detection and Applications for Data Assimilation

    Science.gov (United States)

    Nowottnick, Ed; Yorks, John; McGill, Matt; Scott, Stan; Palm, Stephen; Hlavka, Dennis; Hart, William; Selmer, Patrick; Kupchock, Andrew; Pauly, Rebecca

    2017-01-01

    Using GEOS-5, we are developing a 1D ENS approach for assimilating CATS near real time observations of total attenuated backscatter at 1064 nm: a) After performing a 1-ENS assimilation of a cloud-free profile, the GEOS-5 analysis closely followed observed total attenuated backscatter. b) Vertical localization length scales were varied for the well-mixed PBL and the free troposphere After assimilating a cloud free segment of a CATS granule, the fine detail of a dust event was obtained in the GEOS-5 analysis for both total attenuated backscatter and extinction. Future Work: a) Explore horizontal localization and test within a cloudy aerosol layer. b) Address noisy analysis increments in the free troposphere where both CATS and GEOS-5 aerosol loadings are low. c) Develop a technique to screen CATS ground return from profiles. d) "Dynamic" lidar ratio that will evolve in conjunction with simulated aerosol mixtures.

  5. Improving Sediment Transport Prediction by Assimilating Satellite Images in a Tidal Bay Model of Hong Kong

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-03-01

    Full Text Available Numerical models being one of the major tools for sediment dynamic studies in complex coastal waters are now benefitting from remote sensing images that are easily available for model inputs. The present study explored various methods of integrating remote sensing ocean color data into a numerical model to improve sediment transport prediction in a tide-dominated bay in Hong Kong, Deep Bay. Two sea surface sediment datasets delineated from satellite images from the Moderate Resolution Imaging Spectra-radiometer (MODIS were assimilated into a coastal ocean model of the bay for one tidal cycle. It was found that remote sensing sediment information enhanced the sediment transport model ability by validating the model results with in situ measurements. Model results showed that root mean square errors of forecast sediment both at the surface layer and the vertical layers from the model with satellite sediment assimilation are reduced by at least 36% over the model without assimilation.

  6. 27 CFR 555.186 - Seizure or forfeiture.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Seizure or forfeiture. 555... Seizure or forfeiture. Any plastic explosive that does not contain a detection agent in violation of 18 U.S.C. 842(l)-(n) is subject to seizure and forfeiture, and all provisions of 19 U.S.C. 1595a...

  7. 19 CFR 12.101 - Seizure of prohibited switchblade knives.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Seizure of prohibited switchblade knives. 12.101...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Switchblade Knives § 12.101 Seizure of prohibited... accordance with § 12.100(a) shall be seized under 19 U.S.C. 1595a(c). (b) Notice of seizure. Notice of...

  8. 26 CFR 403.25 - Personal property subject to seizure.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Personal property subject to seizure. 403.25... AND ADMINISTRATION DISPOSITION OF SEIZED PERSONAL PROPERTY Seizures and Forfeitures § 403.25 Personal property subject to seizure. Personal property may be seized by the Commissioner of Internal Revenue or his...

  9. 27 CFR 447.63 - Seizure and forfeiture.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Seizure and forfeiture. 447.63 Section 447.63 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.63 Seizure and forfeiture. Whoever knowingly...

  10. 9 CFR 118.4 - Seizure and condemnation.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Seizure and condemnation. 118.4... AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS DETENTION; SEIZURE AND CONDEMNATION § 118.4 Seizure and condemnation. Any biological product which is prepared, sold, bartered...

  11. 27 CFR 555.166 - Seizure or forfeiture.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Seizure or forfeiture. 555... EXPLOSIVES, DEPARTMENT OF JUSTICE EXPLOSIVES COMMERCE IN EXPLOSIVES Unlawful Acts, Penalties, Seizures and Forfeitures § 555.166 Seizure or forfeiture. Any explosive materials involved or used or intended to be used...

  12. 26 CFR 301.7321-1 - Seizure of property.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Seizure of property. 301.7321-1 Section 301... ADMINISTRATION PROCEDURE AND ADMINISTRATION Other Offenses § 301.7321-1 Seizure of property. Any property subject... director or assistant regional commissioner (alcohol, tobacco, and firearms). Upon seizure of property by...

  13. Complex partial seizure, disruptive behaviours and the Nigerian ...

    African Journals Online (AJOL)

    Background: Complex partial seizure is an epileptic seizure which results in impairment of responsiveness or awareness such as altered level of consciousness. Complex partial seizures are often preceded by an aura such as depersonalization, feelings of de javu, jamais vu and fear. The ictal phase of complex partial ...

  14. Rapidly Learned Identification of Epileptic Seizures from Sonified EEG

    Directory of Open Access Journals (Sweden)

    Psyche eLoui

    2014-10-01

    Full Text Available Sonification refers to a process by which data are converted into sound, providing an auditory alternative to visual display. Currently, the prevalent method for diagnosing seizures in epilepsy is by visually reading a patient’s electroencephalogram (EEG. However, sonification of the EEG data provides certain advantages due to the nature of human auditory perception. We hypothesized that human listeners will be able to identify seizures from EEGs using the auditory modality alone, and that accuracy of seizure identification will increase after a short training session. Here we describe an algorithm we have used to sonify EEGs of both seizure and non-seizure activity, followed by a training study in which subjects listened to short clips of sonified EEGs and determine whether each clip was of seizure or normal activity, both before and after a short training session. Results show that before training subjects performed at chance level in differentiating seizures vs. non-seizures, but there was a significant improvement of accuracy after the training session. After training, subjects successfully distinguished seizures from non-seizures using the auditory modality alone. Further analyses using signal detection theory demonstrated improvement in sensitivity and reduction in response bias as a result of training. This study demonstrates the potential of sonified EEGs to be used for the detection of seizures. Future studies will attempt to increase accuracy using novel training and sonification modifications, with the goals of managing, predicting, and ultimately controlling seizures using sonification as a possible biofeedback-based intervention for epilepsy.

  15. Seizure-like activity during fentanyl anesthesia. A case report.

    OpenAIRE

    Webb, M. D.

    1990-01-01

    Fentanyl induced seizures have been described previously in the literature. Clinical observations has labeled the movements seen in fentanyl anesthesia as seizure activity but electroencephalographic studies have not supported this. A case of seizure-like activity after the administration of fentanyl in a 20-year-old female is reported.

  16. CSF and plasma adipokines after tonic–clonic seizures

    National Research Council Canada - National Science Library

    Palmio, Johanna; Vuolteenaho, Katriina; Lehtimäki, Kai; Nieminen, Riina; Peltola, Jukka; Moilanen, Eeva

    2016-01-01

    ... neurological disorder [4] . Recent studies suggest a role for adipokines in the genesis of seizures and neuroprotection related to seizures [2,5] . Adiponectin has shown neuroprotective effects in hippocampal neurons after kainic-acid induced seizures [6] . To the best of our knowledge, adipokines have not been studied in humans shortly after epileptic sei...

  17. Seizure variables and cognitive performance in patients with epilepsy

    African Journals Online (AJOL)

    Background and Purpose Epilepsy is highly prevalent in developing African countries with significant morbidity, social stigmatization, poor quality of life and preventable mortality. There are scanty reports on the contributions of seizure variables like seizure types, frequency of seizures, duration of epilepsy, age at onset and ...

  18. Out-of-body experiences associated with seizures

    Directory of Open Access Journals (Sweden)

    Bruce eGreyson

    2014-02-01

    Full Text Available Alterations of consciousness are critical factors in the diagnosis of epileptic seizures. With these alterations in consciousness, some persons report sensations of separating from the physical body, experiences that may in rare cases resemble spontaneous out-of-body experiences. This study was designed to identify and characterize these out-of-body-like subjective experiences associated with seizure activity. 55% of the patients in this study recalled some subjective experience in association with their seizures. Among our sample of 100 patients, 7 reported out-of-body experiences associated with their seizures. We found no differentiating traits that were associated with patients’ reports of out-of-body experiences, in terms of either demographics; medical history, including age of onset and duration of seizure disorder, and seizure frequency; seizure characteristics, including localization, lateralization, etiology, and type of seizure, and epilepsy syndrome; or ability to recall any subjective experiences associated with their seizures. Reporting out-of-body experiences in association with seizures did not affect epilepsy-related quality of life. It should be noted that even in those patients who report out-of-body experiences, such sensations are extremely rare events that do not occur routinely with their seizures. Most patients who reported out-of-body experiences described one or two experiences that occurred an indeterminate number of years ago, which precludes the possibility of associating the experience with the particular characteristics of that one seizure or with medications taken or other conditions at the time.

  19. Out-of-body experiences associated with seizures

    Science.gov (United States)

    Greyson, Bruce; Fountain, Nathan B.; Derr, Lori L.; Broshek, Donna K.

    2014-01-01

    Alterations of consciousness are critical factors in the diagnosis of epileptic seizures. With these alterations in consciousness, some persons report sensations of separating from the physical body, experiences that may in rare cases resemble spontaneous out-of-body experiences. This study was designed to identify and characterize these out-of-body-like subjective experiences associated with seizure activity. Fifty-five percent of the patients in this study recalled some subjective experience in association with their seizures. Among our sample of 100 patients, 7 reported out-of-body experiences associated with their seizures. We found no differentiating traits that were associated with patients' reports of out-of-body experiences, in terms of either demographics; medical history, including age of onset and duration of seizure disorder, and seizure frequency; seizure characteristics, including localization, lateralization, etiology, and type of seizure, and epilepsy syndrome; or ability to recall any subjective experiences associated with their seizures. Reporting out-of-body experiences in association with seizures did not affect epilepsy-related quality of life. It should be noted that even in those patients who report out-of-body experiences, such sensations are extremely rare events that do not occur routinely with their seizures. Most patients who reported out-of-body experiences described one or two experiences that occurred an indeterminate number of years ago, which precludes the possibility of associating the experience with the particular characteristics of that one seizure or with medications taken or other conditions at the time. PMID:24592228

  20. Gyratory seizures revisited: a video-EEG study.

    Science.gov (United States)

    Dobesberger, J; Walser, G; Embacher, N; Unterberger, I; Luef, G; Bauer, G; Benke, T; Bartha, L; Ortler, M; Trinka, E

    2005-06-14

    Gyratory seizures (GSs) have been rarely described in generalized as well as in focal epilepsies. They were defined as a rotation around the body axis during a seizure for at least 180 degrees. The mechanisms of generation are unknown and have been discussed controversially. The aim of this investigation was to further delineate seizure semiology and assess a possible lateralizing and localizing value of GSs. The authors screened 277 consecutive patients with intractable epilepsies referred to a University Hospital for presurgical evaluation between 1998 and 2004 for GSs: 169 had temporal lobe epilepsy (TLE), 47 frontal lobe epilepsy (FLE), 38 generalized epilepsies (GE), and 23 had extratemporal or multifocal epilepsy. Twelve patients showed gyratory movements in 17 seizures. Eight had FLE and four TLE (p head followed by a rotation toward the contralateral side of seizure onset. In 42% (5/12), the gyratory movement was not preceded by a forced head version. In these seizures, the direction of the rotation was toward the side of seizure onset. The direction of rotation lateralizes seizure onset zone in focal epilepsy depending on the seizure evolution: 1) gyratory seizures (GSs) starting with a forced version of the head ensuing into a body rotation lateralize seizure onset zone contralateral to the direction of rotation. 2) In GSs without a preceding gyratory forced head version, the direction of rotation is toward the side of seizure onset. GSs occur more frequently in frontal lobe epilepsy than temporal lobe epilepsy, while none of our patients with GSs had generalized epilepsies.

  1. Rapidly learned identification of epileptic seizures from sonified EEG.

    Science.gov (United States)

    Loui, Psyche; Koplin-Green, Matan; Frick, Mark; Massone, Michael

    2014-01-01

    Sonification refers to a process by which data are converted into sound, providing an auditory alternative to visual display. Currently, the prevalent method for diagnosing seizures in epilepsy is by visually reading a patient's electroencephalogram (EEG). However, sonification of the EEG data provides certain advantages due to the nature of human auditory perception. We hypothesized that human listeners will be able to identify seizures from EEGs using the auditory modality alone, and that accuracy of seizure identification will increase after a short training session. Here, we describe an algorithm that we have used to sonify EEGs of both seizure and non-seizure activity, followed by a training study in which subjects listened to short clips of sonified EEGs and determined whether each clip was of seizure or normal activity, both before and after a short training session. Results show that before training subjects performed at chance level in differentiating seizures from non-seizures, but there was a significant improvement of accuracy after the training session. After training, subjects successfully distinguished seizures from non-seizures using the auditory modality alone. Further analyses using signal detection theory demonstrated improvement in sensitivity and reduction in response bias as a result of training. This study demonstrates the potential of sonified EEGs to be used for the detection of seizures. Future studies will attempt to increase accuracy using novel training and sonification modifications, with the goals of managing, predicting, and ultimately controlling seizures using sonification as a possible biofeedback-based intervention for epilepsy.

  2. Pre and post craniotomy psychosis and seizure disorder in a ...

    African Journals Online (AJOL)

    This report highlights psychosis and seizures presenting at two distinct periods of time in the course of Meningioma, in a 43 year old Nigerian medical doctor and buttresses the fact that the risk for post operative seizures and other symptoms include a history of pre-operative seizures and the site of the tumor. The subject ...

  3. Seizures in Patients with Multiple Sclerosis: Epidemiology, Pathophysiology and Management

    OpenAIRE

    Kelley, Brendan J.; Rodriguez, Moses

    2009-01-01

    Seizures have been recognized to occur in multiple sclerosis since early descriptions of the disease. Various studies have attempted to determine the incidence and prevalence of seizures in multiple sclerosis; although they differ in the reported prevalence, seizures do appear to be more common in multiple sclerosis cohorts than in the general population.

  4. Patterns of antiepileptic drug use and seizure control among people ...

    African Journals Online (AJOL)

    Background Epilepsy is characterized by episodic and unpredictable seizure recurrences which are often amenable to medical treatment. Simple and readily available medications can be used to control seizures in epilepsy. However, in many communities in developing countries seizure control among people living with ...

  5. 28 CFR 0.86 - Seizure of gambling devices.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Seizure of gambling devices. 0.86 Section... Bureau of Investigation § 0.86 Seizure of gambling devices. The Director, Associate Director, Assistants... General to make seizures of gambling devices (18 U.S.C. 1955(d), 15 U.S.C. 1171 et seq.) and wire or oral...

  6. The Acceleration of Immigrant Unhealthy Assimilation.

    Science.gov (United States)

    Giuntella, Osea; Stella, Luca

    2017-04-01

    It is well known that immigrants tend to be healthier than US natives and that this advantage erodes with time spent in the USA. However, we know less about the heterogeneity of these trajectories among arrival cohorts. Recent studies have shown that later arrival cohorts of immigrants have lower entry wages and experience less economic assimilation. In this paper, we investigate whether similar cohort effects can be observed in the weight assimilation of immigrants in the USA. Focusing on obesity, we show that more recent immigrant cohorts arrive with higher obesity rates and experience a faster 'unhealthy assimilation' in terms of weight gain. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Optimal transport for variational data assimilation

    Directory of Open Access Journals (Sweden)

    N. Feyeux

    2018-01-01

    Full Text Available Usually data assimilation methods evaluate observation-model misfits using weighted L2 distances. However, it is not well suited when observed features are present in the model with position error. In this context, the Wasserstein distance stemming from optimal transport theory is more relevant.This paper proposes the adaptation of variational data assimilation for the use of such a measure. It provides a short introduction of optimal transport theory and discusses the importance of a proper choice of scalar product to compute the cost function gradient. It also extends the discussion to the way the descent is performed within the minimization process.These algorithmic changes are tested on a nonlinear shallow-water model, leading to the conclusion that optimal transport-based data assimilation seems to be promising to capture position errors in the model trajectory.

  8. A reanalysis of ozone on Mars from assimilation of SPICAM observations

    Science.gov (United States)

    Holmes, James A.; Lewis, Stephen R.; Patel, Manish R.; Lefèvre, Franck

    2018-03-01

    We have assimilated for the first time SPICAM retrievals of total ozone into a Martian global circulation model to provide a global reanalysis of the ozone cycle. Disagreement in total ozone between model prediction and assimilation is observed between 45°S-10°S from LS = 135-180° and at northern polar (60°N-90°N) latitudes during northern fall (LS = 150-195°). Large percentage differences in total ozone at northern fall polar latitudes identified through the assimilation process are linked with excessive northward transport of water vapour west of Tharsis and over Arabia Terra. Modelling biases in water vapour can also explain the underestimation of total ozone between 45°S-10°S from LS = 135-180°. Heterogeneous uptake of odd hydrogen radicals are unable to explain the outstanding underestimation of northern polar total ozone in late northern fall. Assimilation of total ozone retrievals results in alterations of the modelled spatial distribution of ozone in the southern polar winter high altitude ozone layer. This illustrates the potential use of assimilation methods in constraining total ozone where SPICAM cannot observe, in a region where total ozone is especially important for potential investigations of the polar dynamics.

  9. Assimilation of alongtrack satellite SSH altimetry in a coastal circulation model off Oregon

    Science.gov (United States)

    Kurapov, A. L.; Egbert, G. D.; Allen, J. S.

    2009-04-01

    A variational representer-based method is utilized to assimilate alongtrack SSH altimetry observations in a 6-km resolution model of circulation over the shelf and in the coastal transition zone (CTZ) off Oregon (US West coast). The nonlinear model is based on Regional Ocean Modeling System (ROMS). For assimilation, AVRORA tangent linear and adjoint codes developed by the authors have been used. The study period is summer 2008, when the shelf circulation is dominated by the southward alongshore current and upwelling. Throughout the season, coastal currents become unstable and separate in the CTZ. The Oregon shelf is narrow such that the AVISO alongtrack altimetry products do not extend to the shelf. However, these data show spatial variability, on scales of several tens of km, associated with separation of the coastal currents in the CTZ. We perform tests using the Jason data (AVISO absolute dynamic topography) from one track to verify that assimilation of these data can help correct the location of the energetic separated current off Cape Blanco, and that this correction helps to improve forecasts locally over a period of 10 days, until new observations are available along the same track. Also, the impact of assimilation is verified against unassimilated data (satellite SST, coastal HF radar, glider cross-shore hydrographic sections). We find that the success of assimilation strongly depends on the choice of the initial error covariance. The implementation of the covariance based on the multivariate balance operator yields promising results.

  10. PODEn4DVar-based radar data assimilation scheme: formulation and preliminary results from real-data experiments with advanced research WRF (ARW

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2015-02-01

    Full Text Available The Proper Orthogonal Decomposition (POD-based ensemble four-dimensional variational (4DVar assimilation method (referred to as PODEn4DVar is a hybrid assimilation method that exploits the strengths of both the ensemble Kalman filter (EnKF and the 4DVar assimilation method. Its feasibility and validity have been demonstrated using ideal models through observing system simulation experiments (OSSEs. In this study, we further utilise this approach to build a PODEn4DVar-based radar data assimilation scheme (PRAS. In a PRAS, radar observations including radial velocity and reflectivity, after some necessary data preprocessing, are assimilated directly to improve model initialisation. A group of single-observation-based OSSEs are first designed to generally evaluate the validity of PRAS. Subsequently, a group of comparison experiments are also carried out between PRAS and an LETKF-based radar assimilation scheme (LRAS, which shows that PRAS is able to produce results better than (at least as good as LRAS. Thirdly, to evaluate the potential impact for PRAS in the operational context, a group of cycling assimilation experiments of radar data are performed, which demonstrates that PRAS can gradually improve the accuracy of analysis field by cycling assimilation. Finally, a heavy convective-rainfall case study was selected to investigate the performance of PRAS in assimilating real radar observations and the impacts of assimilating radar observations on numerical forecasts, with the Weather Research and Forecasting (WRF model as our forecasting model. The results show that significant improvements in predicting heavy rainfall can be achieved due to the improved initial conditions for the convective system's dynamics and microphysics after assimilating the radar observations with PRAS. In summary, the results show that the PODEn4DVar is a promising method for atmospheric data assimilation.

  11. Automatic seizure detection in rats using Laplacian EEG and verification with human seizure signals.

    Science.gov (United States)

    Feltane, Amal; Faye Boudreaux-Bartels, G; Besio, Walter

    2013-03-01

    Automated detection of seizures is still a challenging problem. This study presents an approach to detect seizure segments in Laplacian electroencephalography (tEEG) recorded from rats using the tripolar concentric ring electrode (TCRE) configuration. Three features, namely, median absolute deviation, approximate entropy, and maximum singular value were calculated and used as inputs into two different classifiers: support vector machines and adaptive boosting. The relative performance of the extracted features on TCRE tEEG was examined. Results are obtained with an overall accuracy between 84.81 and 96.51%. In addition to using TCRE tEEG data, the seizure detection algorithm was also applied to the recorded EEG signals from Andrzejak et al. database to show the efficiency of the proposed method for seizure detection.

  12. Current approach to differential diagnosis of epileptic seizures and pseudo-seizures

    Directory of Open Access Journals (Sweden)

    Adalet Arıkanoğlu

    2011-09-01

    Full Text Available Epileptic seizure is the emergence of various transient signs and symptoms resulting from abnormal excessive electrical discharges and synchronous activity. Pseudoseizure can be defined as clinical events that resemble epileptic attacks which are not associated with central nervous system dysfunction. It is difficult to differentiate between pseudoseizures and epileptic seizures. Treatment of pseudoseizures like epileptic seizures causes the use of unnecessary and inappropriate antiepileptic medications. Patients refer to emergency polyclinics again and again, and examinations are repeated needlessly. Therefore, their life quality deteriorates and this situation causes economic burden at the same time. In this article, we investigate the clinical features, EEG findings, biological parameters and autonomic neural system tests that should be looked out for in order to differentiate between epileptic seizures and pseudoseizures in conjunction with the latest literature studies. J Clin Exp Invest 2011; 2 (3: 330-334.

  13. Seizure Management for School-Age Children

    Science.gov (United States)

    Frueh, Eileen

    2008-01-01

    As many as 325,000 school-age children, ages 5-14, have epilepsy in the U.S. Thankfully, with medication, surgery, a special diet or vagus nerve stimulation, most go to school and fully participate in school activities. Children who continue to have seizures, however, may run into problems. Many of these problems can be overcome or prevented…

  14. Relations between epileptic seizures and headaches.

    Science.gov (United States)

    Gameleira, Fernando Tenório; Ataíde, Luiz; Raposo, Maria Cristina Falcão

    2013-10-01

    To describe headaches in patients with epilepsy and try to identify relations between epileptic seizures and headaches. Cross-sectional study, with 304 patients from the epilepsy out-patient section of University Hospital of Federal University of Alagoas (Brazil) between February 2007 and February 2008. The presence of headaches and their relationships with the epileptic seizures were analyzed. Frequent seizures were associated with a greater tendency of occurrence of headaches (odds ratio=1.6 times, p=0.077). Headaches occurred in 66.1% of the cases. The highest occurrence was of migraine (32.9% of the patients), followed by tension-type headaches (9.2%). Two syndromes with a continuum epilepsy-migraine in the same seizure are worth mentioning: migralepsy in 6.6% and epilepgraine in 10.2% of the patients with epilepsy. A high prevalence of headaches in patients with epilepsy was observed, with emphasis on hybrid crises of epilepsy and migraine. Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  15. Idiopathic first seizure in adult life

    NARCIS (Netherlands)

    C.A. van Donselaar (Cees)

    1990-01-01

    textabstractThis thesis is based on a prospective investigation of 226 patients aged 15 years and older, who were referred to one of the participating hospitals due to a possible idiopathic first seizure. Only those patients were admitted to the study in whom an obvious cause on clinical grounds

  16. Pharmacotherapy for tonic-clonic seizures.

    Science.gov (United States)

    Rheims, Sylvain; Ryvlin, Philippe

    2014-07-01

    Occurrence of generalized tonic-clonic seizures (GTCS) is one of the most important risk factors of seizure-related complications and comorbidities in patients with epilepsy. Their prevention is therefore an important aspect of therapeutic management both in idiopathic generalized epilepsies and in focal epilepsies. It has been shown that the efficacy of antiepileptic drugs (AEDs) varies across epilepsy syndromes, with some AEDs efficacious against focal seizures with secondary GTCS (sGTCS) but aggravating primary GTCS (pGTCS). In patients with pGTCS, evidence-based data support the preferential use of valproic acid, lamotrigine, levetiracetam and topiramate. In patients with sGTCS, all AEDs approved in the treatment of focal epilepsies might be used. Both in pGTCS and sGTCS, additional data are required, specifically to inform about the relative efficacy of AEDs in relation to each other. Although valproic acid might be the most efficacious drug in idiopathic generalized epilepsies, it should be avoided in women of childbearing age due to its safety profile. In patients with sGTCS, AEDs for which the impact on this seizure type has been formally evaluated and which have demonstrated greater efficacy than placebo might preferentially be used, such as lacosamide, perampanel and topiramate.

  17. S100B proteins in febrile seizures

    DEFF Research Database (Denmark)

    Mikkonen, Kirsi; Pekkala, Niina; Pokka, Tytti

    2011-01-01

    at the hospital after FS and S100B concentration in serum (r=-0.130, P=0.28) or in cerebrospinal fluid samples (r=-0.091, P=0.52). Our findings indicate that FS does not cause significant blood-brain barrier openings, and increase the evidence that these seizures are relatively harmless for the developing brain....

  18. Treatment Of Seizures In The Elderly

    Directory of Open Access Journals (Sweden)

    Aleem MA

    2005-01-01

    Full Text Available The increasing life expectancy over the preceding decades and trend towards further increase means that the elderly is now a growing section of the population. Seizures are a particularly common disorder in the age group. Considering that above the age of 50 years, one is prone to suffer from atleast one chromic illness, the interplay between associated medical and neurologic diseases and seizures need to be understood. These comorbidities like hypertension, cerebrovascular accidents, diabetes, renal failure and others not only contribute to seizures, they may also interfere with their appropriate treatment. Seizures, on the other hand, may be the cause of added morbidity like fractures, head injury and poor self esteem which may lead to poor quality of life. In addition, the unique pharmacokinetics, pharmacodynamics and side effect profile of the various antieplileptic drugs in the elderly and the multiple drug interactions, require judicious use along with regular monitoring. However, an ideal antiepileptic drug for the elderly is yet to be found.

  19. Lumbar Puncture for First Simple Febrile Seizure

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2009-01-01

    Full Text Available Compliance with American Academy of Pediatrics consensus statement recommendations regarding lumbar puncture for infants 6-18 months of age with a first simple febrile seizure was investigated by a retrospective review of 704 infants evaluated in the pediatric emergency medicine division at Children’s Hospital Boston, MA, Oct 1995-Oct 2006.

  20. Neonatal seizures: soothing a burning topic.

    Science.gov (United States)

    Thornton, Matthew D; Chen, Lei; Langhan, Melissa L

    2013-10-01

    Neonatal seizures are a potentially life-threatening pediatric problem with a variety of causes, such as birth trauma, asphyxia, congenital anomalies, metabolic disturbances, infections, and drug withdrawal or intoxication. Thorough and timely evaluations of such patients are necessary to identify and treat the underlying etiology, therefore reducing potential morbidity and mortality. We review neonatal seizures and hypocalcemia and present the case of a 6-day-old male infant who presented to a tertiary pediatric emergency department with seizure-like episodes. He was found to have markedly low serum calcium, magnesium, and parathyroid hormone concentrations, as well as a significantly elevated serum phosphate concentration. The etiology of these abnormalities was found to be maternal ingestion of extremely high doses of calcium carbonate during the third trimester of her pregnancy, an occurrence that has been reported only once in the literature. Education pertaining to the dangers of excessive calcium carbonate intake during pregnancy may be an important piece of anticipatory guidance for pregnant mothers with symptoms of gastroesophageal reflux, and questioning the mother of a neonate presenting with seizures about such over-the-counter medications may help to elucidate the diagnosis.

  1. Uncommon Etiology for Seizure: Cerebral Hyperperfusion Syndrome

    Directory of Open Access Journals (Sweden)

    Mohankumar Kurukumbi

    2017-01-01

    Full Text Available Cerebral hyperperfusion syndrome (CHS is a rare life-threatening complication of carotid endarterectomy (CEA and carotid artery stenting (CAS for carotid artery stenosis. The incidence varies between 0 and 3%, depending on the severity of the stenosis, perioperative hypertension, and contralateral carotid stenosis. This case report reports a 53-year-old female patient presenting with decreased alertness and multiple tonic-clonic seizures, in the background of bilateral CEA. She was found to have bilateral carotid stenosis. Her left CEA was performed three months prior and right CEA was four days prior to her current presentation with seizures. After bilateral CEA, the imaging showed extensive pathologic process involving primarily the subcortical white matter and overlying cortex, more on the right cerebral hemisphere. On follow-up six weeks later, she reported no recurrent seizures and imaging showed decrease in abnormal signal intensity of the grey and white matter. This was indicative of near complete resolution of hyperperfusion damage. CHS is a rare complication due to the loss of autoregulation of the cerebrovascular system and increased blood flow status after bilateral CEA. This case is reported because of a rare and unique presentation of seizures in the background of bilateral CEA.

  2. Uncommon Etiology for Seizure: Cerebral Hyperperfusion Syndrome.

    Science.gov (United States)

    Kurukumbi, Mohankumar; Truong, Ahn; Pirsaharkhiz, Naghemeh

    2017-01-01

    Cerebral hyperperfusion syndrome (CHS) is a rare life-threatening complication of carotid endarterectomy (CEA) and carotid artery stenting (CAS) for carotid artery stenosis. The incidence varies between 0 and 3%, depending on the severity of the stenosis, perioperative hypertension, and contralateral carotid stenosis. This case report reports a 53-year-old female patient presenting with decreased alertness and multiple tonic-clonic seizures, in the background of bilateral CEA. She was found to have bilateral carotid stenosis. Her left CEA was performed three months prior and right CEA was four days prior to her current presentation with seizures. After bilateral CEA, the imaging showed extensive pathologic process involving primarily the subcortical white matter and overlying cortex, more on the right cerebral hemisphere. On follow-up six weeks later, she reported no recurrent seizures and imaging showed decrease in abnormal signal intensity of the grey and white matter. This was indicative of near complete resolution of hyperperfusion damage. CHS is a rare complication due to the loss of autoregulation of the cerebrovascular system and increased blood flow status after bilateral CEA. This case is reported because of a rare and unique presentation of seizures in the background of bilateral CEA.

  3. Seizure Triggered by Sick Sinus Syndrome.

    Science.gov (United States)

    Patel, Nilesh; Majeed, Faisal; Sule, Anupam Ashutosh

    2017-11-04

    Sick sinus syndrome (SSS) is a dysfunction of sinoatrial node resulting in symptomatic bradycardia or sinus pauses causing decreased cardiac output with cerebral hypoperfusion and usually presents as syncope, presyncope or fatigue. The occurrence of a seizure is very rare. A 69-year-old man suffered two episodes of generalised tonic-clonic seizures. MRI and electroencephalogram failed to reveal the cause of seizures. In the emergency room, he experienced presyncope simultaneous to bradycardia and sinus pauses. He was stabilised with atropine and dopamine infusion and underwent definitive therapy with a permanent dual-chamber pacemaker with complete symptom resolution. Diagnostic confounders include convulsive syncope and ictal bradycardia. Syncope may be accompanied by myoclonic jerks (convulsive syncope), but postictal confusion is absent. Bradycardia may be seen during the postictal period (ictal bradycardia syndrome), but protracted sinus dysfunction is not present. Hypoperfusion due to significant SSS triggered seizures in this patient who may have an underlying predisposition. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  4. Topiramate monotherapy for partial onset seizures

    National Research Council Canada - National Science Library

    Sachdeo, R C; Reife, R A; Lim, P; Pledger, G

    1997-01-01

    .... A total of 48 patients were evaluated in a double-blind, parallel-group trial. During a 56-day baseline period, patients had at least eight partial onset seizures while being treated with one or two standard antiepileptic drugs (AEDs...

  5. Unscented Kalman filter assimilation of time-lapse self-potential data for monitoring solute transport

    Science.gov (United States)

    Cui, Yi-an; Liu, Lanbo; Zhu, Xiaoxiong

    2017-08-01

    Monitoring the extent and evolution of contaminant plumes in local and regional groundwater systems from existing landfills is critical in contamination control and remediation. The self-potential survey is an efficient and economical nondestructive geophysical technique that can be used to investigate underground contaminant plumes. Based on the unscented transform, we have built a Kalman filtering cycle to conduct time-lapse data assimilation for monitoring the transport of solute based on the solute transport experiment using a bench-scale physical model. The data assimilation was formed by modeling the evolution based on the random walk model and observation correcting based on the self-potential forward. Thus, monitoring self-potential data can be inverted by the data assimilation technique. As a result, we can reconstruct the dynamic process of the contaminant plume instead of using traditional frame-to-frame static inversion, which may cause inversion artifacts. The data assimilation inversion algorithm was evaluated through noise-added synthetic time-lapse self-potential data. The result of the numerical experiment shows validity, accuracy and tolerance to the noise of the dynamic inversion. To validate the proposed algorithm, we conducted a scaled-down sandbox self-potential observation experiment to generate time-lapse data that closely mimics the real-world contaminant monitoring setup. The results of physical experiments support the idea that the data assimilation method is a potentially useful approach for characterizing the transport of contamination plumes using the unscented Kalman filter (UKF) data assimilation technique applied to field time-lapse self-potential data.

  6. Assimilation for Skin SST in the NASA GEOS Atmospheric Data Assimilation System

    Science.gov (United States)

    Akella, Santha; Todling, Ricardo; Suarez, Max

    2017-01-01

    The present article describes the sea surface temperature (SST) developments implemented in the Goddard Earth Observing System, Version 5 (GEOS) Atmospheric Data Assimilation System (ADAS). These are enhancements that contribute to the development of an atmosphere-ocean coupled data assimilation system using GEOS. In the current quasi-operational GEOS-ADAS, the SST is a boundary condition prescribed based on the OSTIA product, therefore SST and skin SST (Ts) are identical. This work modifies the GEOS-ADAS Ts by modelling and assimilating near sea surface sensitive satellite infrared (IR) observations. The atmosphere-ocean interface layer of the GEOS atmospheric general circulation model (AGCM) is updated to include near-surface diurnal warming and cool-skin effects. The GEOS analysis system is also updated to directly assimilate SST-relevant Advanced Very High Resolution Radiometer (AVHRR) radiance observations. Data assimilation experiments designed to evaluate the Ts modification in GEOS-ADAS show improvements in the assimilation of radiance observations that extend beyond the thermal infrared bands of AVHRR. In particular, many channels of hyperspectral sensors, such as those of the Atmospheric Infrared Sounder (AIRS), and Infrared Atmospheric Sounding Interferometer (IASI) are also better assimilated. We also obtained improved fit to withheld insitu buoy measurement of near-surface SST. Evaluation of forecast skill scores show neutral to marginal benefit from the modified Ts.

  7. Characteristics of seizure-induced signal changes on MRI in patients with first seizures.

    Science.gov (United States)

    Kim, Si Eun; Lee, Byung In; Shin, Kyong Jin; Ha, Sam Yeol; Park, JinSe; Park, Kang Min; Kim, Hyung Chan; Lee, Joonwon; Bae, Soo-Young; Lee, Dongah; Kim, Sung Eun

    2017-05-01

    The aim of this study was to investigate the predictive factors and identify the characteristics of the seizure-induced signal changes on MRI (SCM) in patients with first seizures. We conducted a retrospective study of patients with first seizures from March 2010 to August 2014. The inclusion criteria for this study were patients with 1) first seizures, and 2) MRI and EEG performed within 24h of the first seizures. The definition of SCM was hyper-intensities in the brain not applying to cerebral arterial territories. Multivariate logistic regression was performed with or without SCM as a dependent variable. Of 431 patients with seizures visiting the ER, 69 patients met the inclusion criteria. Of 69 patients, 11 patients (15.9%) had SCM. Epileptiform discharge on EEG (OR 29.7, 95% CI 1.79-493.37, p=0.018) was an independently significant variable predicting the presence of SCM in patients with first seizures. In addition, the topography of SCM was as follows; i) ipsilateral hippocampus, thalamus and cerebral cortex (5/11), ii) unilateral cortex (4/11), iii) ipsilateral thalamus and cerebral cortex (1/11), iv) bilateral hippocampus (1/11). Moreover, 6 out of 7 patients who underwent both perfusion CT and MRI exhibited unilateral cortical hyperperfusion with ipsilateral thalamic involvement reflecting unrestricted vascular territories. There is an association between epileptiform discharges and SCM. Additionally, the involvement of the unilateral cortex and ipsilateral thalamus in SCM and its hyperperfusion state could be helpful in differentiating the consequences of epileptic seizures from other pathologies. Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  8. Clinical and economic burden of breakthrough seizures.

    Science.gov (United States)

    Divino, Victoria; Petrilla, Allison A; Bollu, Vamsi; Velez, Fulton; Ettinger, Alan; Makin, Charles

    2015-10-01

    The purpose of this study was to measure health-care resource utilization and costs in treatment-adherent, previously seizure-free patients with epilepsy who were treated in the inpatient/emergency room (ER) setting for new-onset seizures, compared with matched controls. The study used a retrospective case/control study design using administrative claims from the IMS PharMetrics™ database. We identified adult patients with epilepsy with 1+ ER visit/hospitalization with primary diagnosis of epilepsy between 1/1/2006 and 3/31/2011, preceded by 6months of seizure-free activity and antiepileptic drug (AED) treatment adherence (≥80% of days covered by any AED); the first observed seizure defined the "breakthrough" seizure/index event. Treatment-adherent patients with epilepsy without any ER/hospital admission for seizures served as controls: an outpatient epilepsy-related medical claim within the selection window was chosen at random as the index date. The following were continuous enrollment requirements for all patients: ≥12-month pre- and ≥6-month postindex. Each case matched 1:1 to a control using propensity score matching. All-cause and epilepsy-related (epilepsy/convulsion diagnosis, AED pharmacy) resource utilization and unadjusted and adjusted direct health-care costs (per person, 2012 US dollars (USD)) were assessed in a 6-month follow-up period. There were 5729 cases and 14,437 controls eligible. The final sample comprised 5279 matched case/control pairs. In unadjusted analyses, matched cases had significantly higher rates of all-cause hospitalization and ER visits compared to controls and significantly higher total all-cause direct health-care costs (median $12,714 vs. $5095, pseizure (driven by inpatient costs). Cases had 2.3 times higher adjusted all-cause costs and 8.1 times higher adjusted epilepsy-related costs than controls (both pseizures occurred among 28.4% of our treatment-adherent study sample and were associated with significant

  9. Vortex Models for Data Assimilation

    OpenAIRE

    Darakananda, Darwin

    2017-01-01

    Inviscid vortex models have been used for decades to investigate unsteady aerodynamics. However, real-time use of these models has been hindered by the tradeoff between increasing a model's dynamical capability and reducing its dimensionality. In this work, we present two different solutions to this problem. First, we develop a hybrid model where vortex sheets represent shear layers that separate from the wing and point vortices represent the rolled-up cores of these shear layers and the o...

  10. Data assimilation approaches in the EURANOS project

    DEFF Research Database (Denmark)

    Kaiser, J.C.; Gering, F.; Astrup, Poul

    2010-01-01

    Within the EURANOS project data assimilation (DA) approaches have been successfully applied in two areas to improve the predictive power of simulation models used in the RODOS and ARGOS decision support systems. For the areas of atmospheric dispersion modelling and of modelling the fate of radio......-nuclides in urban areas the results of demonstration exercises are presented here. With the data assimilation module of the RIMPUFF dispersion code, predictions of the gamma dose rate are corrected with simulated readings of fixed detector stations. Using the DA capabilities of the IAMM package for mapping...

  11. Optimising assimilation of hydrographic profiles into isopycnal ocean models with ensemble data assimilation

    Science.gov (United States)

    Wang, Yiguo; Counillon, François; Bethke, Ingo; Keenlyside, Noel; Bocquet, Marc; Shen, Mao-lin

    2017-06-01

    Hydrographic profiles are crucial observational datasets for constraining ocean models and their vertical structure. In this study, we investigate a key implementation setup for optimising their assimilation into isopycnal ocean models. For this purpose, we use the Norwegian Climate Prediction Model (NorCPM), which is a fully-coupled climate prediction system based on the Norwegian Earth System Model and the ensemble Kalman filter. First, we revisit whether it is more accurate to assimilate observations in their original coordinate (z-level coordinate) or to transform them into isopycnal coordinates prior to assimilation. The analysis is performed with a single assimilation step using synthetic observations that mimic the characteristic properties of hydrographic profiles: varying vertical resolutions, profiles of only temperature and observations only in the top 1000 m. Assimilating profiles in their native coordinate (z-level coordinates) performs best because converting observations into isopycnal coordinates is strongly non-linear which reduces the efficiency of the assimilation. Secondly, we investigate how to set the horizontal localisation radius for our system. A radius that varies with latitude following a bimodal Gaussian function fits the system well. Thirdly, we estimate observation error, which consists of both instrumental error and representativeness error. In the proposed formulation only the instrumental error decreases with the number of observations during superobing, because the representativeness error is dominated by model limitation. Finally, we demonstrate the impact of assimilating hydrographic profiles from the observational EN4 dataset into NorCPM. An analysis of 10 years with monthly assimilation is performed with special focus on assessing the accuracy and the reliability of our analysis. The assimilation of hydrographic profiles into NorCPM is found to efficiently reduce the model bias and error, and the ensemble spread is found to be

  12. Early and late postoperative seizure outcome in 97 patients with supratentorial meningioma and preoperative seizures: a retrospective study.

    Science.gov (United States)

    Zheng, Zhe; Chen, Peng; Fu, Weiming; Zhu, Junming; Zhang, Hong; Shi, Jian; Zhang, Jianmin

    2013-08-01

    We identified factors associated with early and late postoperative seizure control in patients with supratentorial meningioma plus preoperative seizures. In this retrospective study, univariate analysis and multivariate logistic regression analysis compared 24 clinical variables according to the occurrence of early (≤1 week) or late (>1 week) postoperative seizures. Sixty-two of 97 patients (63.9 %) were seizure free for the entire postoperative follow-up period (29.5 ± 11.8 months), while 13 patients (13.4 %) still had frequent seizures at the end of follow-up. Fourteen of 97 patients (14.4 %) experienced early postoperative seizures, and emergence of new postoperative neurological deficits was the only significant risk factor (odds ratio = 7.377). Thirty-three patients (34.0 %) experienced late postoperative seizures at some time during follow-up, including 12 of 14 patients with early postoperative seizures. Associated risk factors for late postoperative seizures included tumor progression (odds ratio = 7.012) and new permanent postoperative neurological deficits (odds ratio = 4.327). Occurrence of postoperative seizures in patients with supratentorial meningioma and preoperative seizure was associated with new postoperative neurological deficits. Reduced cerebral or vascular injury during surgery may lead to fewer postoperative neurological deficits and better seizure outcome.

  13. Seizure precipitants in a community-based epilepsy cohort.

    Science.gov (United States)

    Wassenaar, Merel; Kasteleijn-Nolst Trenité, Dorothée G A; de Haan, Gerrit-Jan; Carpay, Johannes A; Leijten, Frans S S

    2014-04-01

    Epileptic seizures can be provoked by several factors. Better understanding of these factors may improve a patient's sense of control and could reduce seizures. In daily practice, the recognition of seizure precipitants relies heavily on clinical or video-EEG evidence, which can be difficult to obtain. Studies of seizure provocation are largely based on selected hospital-based patient populations, which may lead to biased occurrence estimates. Self-reported seizure precipitants are rarely studied, yet are necessary to understand the experiences of patients and improve epilepsy management. We performed a cross-sectional community-based study of 248 epilepsy patients, selected by pharmacy records of anti-epileptic drug use. Self-reported seizure precipitants and potential associated characteristics were assessed using questionnaires. Almost half of all patients (47 %) reported one or more seizure precipitants, of which stress, sleep deprivation, and flickering lights were the most common. In this community-based setting, light-provoked seizures were especially frequent compared to the literature. Idiopathic generalized epilepsy (IGE), a lower age at seizure onset, and having auras or prodromes were found to be important independent prognostic factors associated with provoked seizures. IGE and a younger age at seizure onset have been linked to provoked seizures in earlier reports. The finding of auras or prodromes as a prognostic factor was unexpected, though case reports have described provoked seizures in patients having auras. Assessment of these factors may facilitate the early recognition of seizure precipitants in daily clinical practice. This is important for the optimization of epilepsy management for a large group of patients, as provoked seizures are expected to occur frequently.

  14. Influence of seizures on early development in tuberous sclerosis complex.

    Science.gov (United States)

    Capal, Jamie K; Bernardino-Cuesta, Beatriz; Horn, Paul S; Murray, Donna; Byars, Anna Weber; Bing, Nicole M; Kent, Bridget; Pearson, Deborah A; Sahin, Mustafa; Krueger, Darcy A

    2017-05-01

    Epilepsy is commonly seen in Tuberous Sclerosis Complex (TSC). The relationship between seizures and developmental outcomes has been reported, but few studies have examined this relationship in a prospective, longitudinal manner. The objective of the study was to evaluate the relationship between seizures and early development in TSC. Analysis of 130 patients ages 0-36months with TSC participating in the TSC Autism Center of Excellence Network, a large multicenter, prospective observational study evaluating biomarkers predictive of autism spectrum disorder (ASD), was performed. Infants were evaluated longitudinally with standardized evaluations, including cognitive, adaptive, and autism-specific measures. Seizure history was collected continuously throughout, including seizure type and frequency. Data were analyzed at 6, 12, 18, and 24months of age. Patients without a history of seizures performed better on all developmental assessments at all time points compared to patients with a history of seizures and exhibited normal development at 24months. Patients with a history of seizures not only performed worse, but developmental progress lagged behind the group without seizures. All patients with a history of infantile spasms performed worse on all developmental assessments at 12, 18, and 24months. Higher seizure frequency correlated with poorer outcomes on developmental testing at all time points, but particularly at 12months and beyond. Patients with higher seizure frequency during infancy continued to perform worse developmentally through 24months. A logistic model looking at the individual impact of infantile spasms, seizure frequency, and age of seizure onset as predictors of developmental delay revealed that age of seizure onset was the most important factor in determining developmental outcome. Results of this study further define the relationship between seizures and developmental outcomes in young children with TSC. Early seizure onset in infants with TSC

  15. Evaluation of Seizure Attacks in Patients with Cerebrovascular Accident

    Directory of Open Access Journals (Sweden)

    Ebrahim Koochaki

    2013-04-01

    Full Text Available Background: The most common reason for seizure in elderly duration is the stroke. This study was conducted aiming to assess the frequency of seizure attack occurrence in those patients. Materials and Methods: This investigation was carried out through a cross-sectional method for one year on 330 patients admitted to the neurology ward as diagnosed with stroke. The required data was collected through the researcher-made questionnaire from the patients suffering from stoke which was diagnosed based on clinical findings, CT-Scan and MRI as required. Results: Among 330 patient suffering from stroke (162 men and 168 women, 48 cases (14.5% were suffering from seizure. Six percent of the patients had early seizure and another 8.5% had late seizure. Among 162 men suffering from the stroke, 32 ones were without seizures and 30 men were suffering the seizure. A number of 150 women out of total 168 ones suffering from the stroke, had no seizure and 18 others had seizures; frequency of seizure occurrence was more in male samples (p=0.044. In the people under 60 year, there were mostly early types of seizure (45% and in the age range above 60 year, it was mostly late type (89.3%. A 68.5% of the patients suffering from the seizure had experienced ischemic stroke. However, the frequency of seizure occurrence in the patients with hemorrhagic stroke was statistically greater (p=0.003. Conclusion: This examination showed that occurrence of seizure attacks in the people with stroke is 14.5% and it is seen more in the hemorrhagic strokes than ischemic ones. The frontoparietal area is the most common location involved and tonic clonic was the most common seizure in the patients suffering from it who have experienced the stroke

  16. Seizure Forecasting from Idea to Reality. Outcomes of the My Seizure Gauge Epilepsy Innovation Institute Workshop

    Science.gov (United States)

    French, Jaqueline A.; Fureman, Brandy E.

    2017-01-01

    Abstract The Epilepsy Innovation Institute (Ei2) is a new research program of the Epilepsy Foundation designed to be an innovation incubator for epilepsy. Ei2 research areas are selected based on community surveys that ask people impacted by epilepsy what they would like researchers to focus on. In their 2016 survey, unpredictability was selected as a top issue regardless of seizure frequency or severity. In response to this need, Ei2 launched the My Seizure Gauge challenge, with the end goal of creating a personalized seizure advisory system device. Prior to moving forward, Ei2 convened a diverse group of stakeholders from people impacted by epilepsy and clinicians, to device developers and data scientists, to basic science researchers and regulators, for a state of the science assessment on seizure forecasting. From the discussions, it was clear that we are at an exciting crossroads. With the advances in bioengineering, we can utilize digital markers, wearables, and biosensors as parameters for a seizure-forecasting algorithm. There are also over a thousand individuals who have been implanted with ambulatory intracranial EEG recording devices. Pairing up peripheral measurements to brain states could identify new relationships and insights. Another key component is the heterogeneity of the relationships indicating that pooling findings across groups is suboptimal, and that data collection will need to be done on longer time scales to allow for individualization of potential seizure-forecasting algorithms.

  17. Seizure Forecasting from Idea to Reality. Outcomes of the My Seizure Gauge Epilepsy Innovation Institute Workshop.

    Science.gov (United States)

    Dumanis, Sonya B; French, Jaqueline A; Bernard, Christophe; Worrell, Gregory A; Fureman, Brandy E

    2017-01-01

    The Epilepsy Innovation Institute (Ei2) is a new research program of the Epilepsy Foundation designed to be an innovation incubator for epilepsy. Ei2 research areas are selected based on community surveys that ask people impacted by epilepsy what they would like researchers to focus on. In their 2016 survey, unpredictability was selected as a top issue regardless of seizure frequency or severity. In response to this need, Ei2 launched the My Seizure Gauge challenge, with the end goal of creating a personalized seizure advisory system device. Prior to moving forward, Ei2 convened a diverse group of stakeholders from people impacted by epilepsy and clinicians, to device developers and data scientists, to basic science researchers and regulators, for a state of the science assessment on seizure forecasting. From the discussions, it was clear that we are at an exciting crossroads. With the advances in bioengineering, we can utilize digital markers, wearables, and biosensors as parameters for a seizure-forecasting algorithm. There are also over a thousand individuals who have been implanted with ambulatory intracranial EEG recording devices. Pairing up peripheral measurements to brain states could identify new relationships and insights. Another key component is the heterogeneity of the relationships indicating that pooling findings across groups is suboptimal, and that data collection will need to be done on longer time scales to allow for individualization of potential seizure-forecasting algorithms.

  18. Physics of the Brain: Interaction of the Optical-Fiber-Guided Multi-Ultraviolet-Photon Beams with the Epilepsy Topion, (the Seizure Onset Area)

    Science.gov (United States)

    Stefan, V. Alexander

    A novel method for the possible prevention of epileptic seizures is proposed, based on the multi-ultraviolet-photon beam interaction with the epilepsy topion, (nonlinear coupling of an ultra high frequency mode to the brain beta phonons). It is hypothesized that epilepsy is a chaotic-dynamics phenomenon: small electrical changes in the epilepsy-topion lead, (within the 10s of milliseconds), to the onset of chaos, (seizure--excessive electrical discharge), and subsequent cascading into adjacent areas. The ultraviolet photons may control the imbalance of sodium and potassium ions and, consequently, may prove to be efficient in the prevention of epileptic seizures. Supported by Nikola Tesla Labs, Stefan University.

  19. Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation.

    OpenAIRE

    Rezusta, A; Rubio, M. C.; Alejandre, M C

    1991-01-01

    Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.

  20. Altimeter data assimilation in the tropical Indian Ocean using water ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 121; Issue 1. Altimeter data assimilation in the tropical Indian Ocean using water property ... Keywords. Data assimilation; altimeter data; ocean general circulation model; thermocline depth; sea surface temperature; modeling; oceanography; remote sensing.

  1. Risk Factors for Preoperative Seizures and Loss of Seizure Control in Patients Undergoing Surgery for Metastatic Brain Tumors.

    Science.gov (United States)

    Wu, Adela; Weingart, Jon D; Gallia, Gary L; Lim, Michael; Brem, Henry; Bettegowda, Chetan; Chaichana, Kaisorn L

    2017-08-01

    Metastatic brain tumors are the most common brain tumors in adults. Patients with metastatic brain tumors have poor prognoses with median survival of 6-12 months. Seizures are a major presenting symptom and cause of morbidity and mortality. In this article, risk factors for the onset of preoperative seizures and postoperative seizure control are examined. Adult patients who underwent resection of one or more brain metastases at a single institution between 1998 and 2011 were reviewed retrospectively. Of 565 patients, 114 (20.2%) patients presented with seizures. Factors independently associated with preoperative seizures were preoperative headaches (P = 0.044), cognitive deficits (P = 0.031), more than 2 intracranial metastatic tumors (P = 0.013), temporal lobe location (P = 0.031), occipital lobe location (P = 0.010), and bone involvement by tumor (P = 0.029). Factors independently associated with loss of seizure control after surgical resection were preoperative seizures (P = 0.001), temporal lobe location (P = 0.037), lack of postoperative chemotherapy (P = 0.010), subtotal resection of tumor (P = 0.022), and local recurrence (P = 0.027). At last follow-up, the majority of patients (93.8%) were seizure-free. Thirty patients (5.30%) in total had loss of seizure control, and only 8 patients (1.41%) who did not have preoperative seizures presented with new-onset seizures after surgical resection of their metastases. The brain is a common site for metastases from numerous primary cancers, such as breast and lung. The identification of factors associated with onset of preoperative seizures as well as seizure control postoperatively could aid management strategies for patients with metastatic brain tumors. Patients with preoperative seizures who underwent resection tended to have good seizure control after surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Closed-loop seizure control on epileptic rat models

    Science.gov (United States)

    Liang, Sheng-Fu; Liao, Yi-Cheng; Shaw, Fu-Zen; Chang, Da-Wei; Young, Chung-Ping; Chiueh, Herming

    2011-08-01

    In this paper numerous alternative treatments in addition to pharmacological therapy are proposed for their use in epileptic patients. Epileptic animal models can play a crucial role in the performance evaluation of new therapeutic techniques. The objective of this research is to first develop various epileptic rat models; second, develop a portable wireless closed-loop seizure controller including on-line seizure detection and real-time electrical stimulation for seizure elimination; and third, apply the developed seizure controller to the animal models to perform on-line seizure elimination. The closed-loop seizure controller was applied to three Long-Evans rats with spontaneous spike-wave discharges (non-convulsive) and three Long-Evans rats with epileptiform activities induced by pentylenetetrazol (PTZ) injection (convulsive) for evaluation. The seizure detection accuracy is greater than 92% (up to 99%), and averaged seizure detection latency is less than 0.6 s for both spontaneous non-convulsive and PTZ-induced convulsive seizures. The average false stimulation rate is 3.1%. Near 30% of PTZ-induced convulsive seizures need more than two times of 0.5 s electrical stimulation for suppression and 90% of the non-convulsive seizures can be suppressed by only one 0.5 s electrical stimulation.

  3. Probability of detection of clinical seizures using heart rate changes.

    Science.gov (United States)

    Osorio, Ivan; Manly, B F J

    2015-08-01

    Heart rate-based seizure detection is a viable complement or alternative to ECoG/EEG. This study investigates the role of various biological factors on the probability of clinical seizure detection using heart rate. Regression models were applied to 266 clinical seizures recorded from 72 subjects to investigate if factors such as age, gender, years with epilepsy, etiology, seizure site origin, seizure class, and data collection centers, among others, shape the probability of EKG-based seizure detection. Clinical seizure detection probability based on heart rate changes, is significantly (pprobability of detecting clinical seizures (>0.8 in the majority of subjects) using heart rate is highest for complex partial seizures, increases with a patient's years with epilepsy, is lower for females than for males and is unrelated to the side of hemisphere origin. Clinical seizure detection probability using heart rate is multi-factorially dependent and sufficiently high (>0.8) in most cases to be clinically useful. Knowledge of the role that these factors play in shaping said probability will enhance its applicability and usefulness. Heart rate is a reliable and practical signal for extra-cerebral detection of clinical seizures originating from or spreading to central autonomic network structures. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  4. Analyzing reliability of seizure diagnosis based on semiology.

    Science.gov (United States)

    Jin, Bo; Wu, Han; Xu, Jiahui; Yan, Jianwei; Ding, Yao; Wang, Z Irene; Guo, Yi; Wang, Zhongjin; Shen, Chunhong; Chen, Zhong; Ding, Meiping; Wang, Shuang

    2014-12-01

    This study aimed to determine the accuracy of seizure diagnosis by semiological analysis and to assess the factors that affect diagnostic reliability. A total of 150 video clips of seizures from 50 patients (each with three seizures of the same type) were observed by eight epileptologists, 12 neurologists, and 20 physicians (internists). The videos included 37 series of epileptic seizures, eight series of physiologic nonepileptic events (PNEEs), and five series of psychogenic nonepileptic seizures (PNESs). After observing each video, the doctors chose the diagnosis of epileptic seizures or nonepileptic events for the patient; if the latter was chosen, they further chose the diagnosis of PNESs or PNEEs. The overall diagnostic accuracy rate for epileptic seizures and nonepileptic events increased from 0.614 to 0.660 after observations of all three seizures (p semiological diagnosis of seizures is greatly affected by the seizure type as well as the doctor's experience. Although the overall reliability is limited, it can be improved by observing more seizures. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Seizure semiology of lesional frontal lobe epilepsies in children.

    Science.gov (United States)

    Battaglia, D; Lettori, D; Contaldo, I; Veredice, C; Sacco, A; Vasco, J; Martinelli, D; Chieffo, D; Tartaglione, T; Colosimo, C; Di Rocco, C; Guzzetta, F

    2007-12-01

    The aim of the study was to analyse the semiology of seizures in children with frontal lobe epilepsy (FLE) and to compare them with other paediatric cohorts described in the literature as well as with adult counterparts. We analysed 174 registered seizures of 18 cases under 12 years with lesional epilepsy whose frontal origin was defined by the concordance of neuroimaging and ictal electrographic findings, and confirmed by surgery in the six cases operated on. Seizures were generally short, with a high daily frequency and usually related to sleep. The most characteristic semiological pattern consisted of complex motor seizures, particularly hypermotor. Often seizures corresponded to a mixture of different semiological patterns (tonic, gelastic, automotor, hypermotor, versive) presenting in the same seizure, often as a unique type in the same patient. With regard to several aspects the semiology of FLE in our cohort looks like that reported in adult series, in particular as to the frequency of complex motor seizures. However, our cohort was also characterised by a more protean array of seizure semiology, stressing the occurrence of seizures typically present in adults (versive and complex motor) and of some seizure patterns more characteristic in children such as epileptic spasms; moreover, the rare occurrence of secondarily generalised tonic clonic seizures (SGTCS) was confirmed.

  6. Cloxacillin-induced seizure in a hemodialysis patient.

    Science.gov (United States)

    El Nekidy, Wasim; Dziamarski, Nicole; Soong, Derrick; Donaldson, Christine; Ibrahim, Muhieldean; Kadri, Albert

    2015-10-01

    We are reporting a cloxacillin-induced seizure in a patient with stage 5 chronic kidney disease requiring hemodialysis. To our knowledge, there are no published case reports of seizures induced by parenteral cloxacillin in hemodialysis patients. A young hemodialysis female was admitted to the hospital with decreased level of consciousness. Blood cultures revealed methicillin-sensitive Staphylococcus aureus where cloxacillin 2 g intravenously every 4 hours was initiated. Head computed tomography (CT) was not significant. After 14 hours of cloxacillin therapy (4 doses), the patient demonstrated tonic/clonic seizure activity, where phenytoin and lorazepam were initiated. The anti-seizure medications partially reduced seizure activity. Once the cloxacillin was discontinued, the seizures stopped. Two weeks later, all anti-seizure medications were stopped with no further seizure activity. Cloxacillin elimination in hemodialysis patients is similar to patients with normal kidney function. Although cloxacillin does not significantly cross the blood-brain barrier, the correlation between the start of seizures and cloxacillin initiation was confirmed by the negative CT and blood chemistry laboratory results. Moreover, seizure activity was terminated upon discontinuation of cloxacillin. Although further investigation for the cause of such seizures is warranted, clinicians should use caution when giving high doses of cloxacillin in hemodialysis patients. © 2015 International Society for Hemodialysis.

  7. Quantitative analysis of surface electromyography during epileptic and nonepileptic convulsive seizures.

    Science.gov (United States)

    Beniczky, Sándor; Conradsen, Isa; Moldovan, Mihai; Jennum, Poul; Fabricius, Martin; Benedek, Krisztina; Andersen, Noémi; Hjalgrim, Helle; Wolf, Peter

    2014-07-01

    To investigate the characteristics of sustained muscle activation during convulsive epileptic and psychogenic nonepileptic seizures (PNES), as compared to voluntary muscle activation. The main goal was to find surface electromyography (EMG) features that can distinguish between convulsive epileptic seizures and convulsive PNES. In this case-control study, surface EMG was recorded from the deltoid muscles during long-term video-electroencephalography (EEG) monitoring in 25 patients and in 21 healthy controls. A total of 46 clinical episodes were recorded: 28 generalized tonic-clonic seizures (GTCS) from 14 patients with epilepsy, and 18 convulsive PNES from 12 patients (one patient had both GTCS and PNES). The healthy controls were simulating GTCS. To quantitatively characterize the signals we calculated the following parameters: root mean square (RMS) of the amplitude, median frequency (MF), coherence, and duration of the seizures, of the clonic EMG discharges, and of the silent periods between the cloni. Based on wavelet analysis, we distinguished between a low-frequency component (LF 2-8 Hz) and a high-frequency component (HF 64-256 Hz). Duration of the seizure, and separation between the tonic and the clonic phases distinguished at group-level but not at individual level between convulsive PNES and GTCS. RMS, temporal dynamics of the HF/LF ratio, and the evolution of the silent periods differentiated between epileptic and nonepileptic convulsive seizures at the individual level. A combination between HF/LF ratio and RMS separated all PNES from the GTCS. A blinded review of the EMG features distinguished correctly between GTCS and convulsive PNES in all cases. The HF/LF ratio and the RMS of the PNES were smaller compared to the simulated seizures. In addition to providing insight into the mechanism of muscle activation during convulsive PNES, these results have diagnostic significance, at the individual level. Surface EMG features can accurately distinguish

  8. Content analysis of subjective experiences in partial epileptic seizures.

    Science.gov (United States)

    Johanson, Mirja; Valli, Katja; Revonsuo, Antti; Wedlund, Jan-Eric

    2008-01-01

    A new content analysis method for systematically describing the phenomenology of subjective experiences in connection with partial epileptic seizures is described. Forty patients provided 262 descriptions of subjective experience relative to their partial epileptic seizures. The results revealed that subjective experiences during seizures consist mostly of sensory and bodily sensations, hallucinatory experiences, and thinking. The majority of subjective experiences during seizures are bizarre and distorted; nevertheless, the patients are able to engage in adequate behavior. To the best of our knowledge, this is the first study for which detailed subjective seizure descriptions were collected immediately after each seizure and the first study in which the content of verbal reports of subjective experiences during seizures, including both the ictal and postictal experiences, has been analyzed in detail.

  9. Analysis of Seizure EEG in Kindled Epileptic Rats

    Directory of Open Access Journals (Sweden)

    A. K. Sen

    2007-01-01

    Full Text Available Using wavelet analysis we have detected the presence of chirps in seizure EEG signals recorded from kindled epileptic rats. Seizures were induced by electrical stimulation of the amygdala and the EEG signals recorded from the amygdala were analyzed using a continuous wavelet transform. A time–frequency representation of the wavelet power spectrum revealed that during seizure the EEG signal is characterized by a chirp-like waveform whose frequency changes with time from the onset of seizure to its completion. Similar chirp-like time–frequency profiles have been observed in newborn and adult patients undergoing epileptic seizures. The global wavelet spectrum depicting the variation of power with frequency showed two dominant frequencies with the largest amounts of power during seizure. Our results indicate that a kindling paradigm in rats can be used as an animal model of human temporal lobe epilepsy to detect seizures by identifying chirp-like time–frequency variations in the EEG signal.

  10. Significance of Assimilation and Fractional Crystallization (AFC ...

    Indian Academy of Sciences (India)

    57

    Science. 323(5917):1017-8. Nicholson H, Condomines M, Fitton JG, Fallick Ae, Grönvold K And Rogers G 1991 Geochemical and isotopic evidence for crustal assimilation beneath krafla, Iceland. J Petrol. 32(5):1005-20. Paul D, White WM and Blichert‐Toft J 2005 Geochemistry of Mauritius and the origin of rejuvenescent.

  11. CH Waddington, Canalisation and Genetic Assimilation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 6. C. H. Waddington, Canalisation and Genetic Assimilation. Vidyanand Nanjundiah. General Article Volume 15 Issue 6 June 2010 pp 503-513. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. DIVERSE APPROACHES TO MODELLING THE ASSIMILATIVE ...

    African Journals Online (AJOL)

    This study evaluated the assimilative capacity of Ikpoba River using different approaches namely: homogeneous differential equation, ANOVA/Duncan Multiple rage test, first and second order differential equations, correlation analysis, Eigen values and eigenvectors, multiple linear regression, bootstrapping and far-field ...

  13. Radiance Data Assimilation for Binary Typhoon Cases

    Science.gov (United States)

    Choi, Y.; Snyder, C.; Cha, D. H.

    2015-12-01

    The predictability of track and intensity for binary tropical cyclones (TCs) is relatively low due to the interaction between two TCs. In this study, radiance data were assimilated using the Three Dimensional Variational (3D-Var) data assimilation method to improve track and intensity forecasts of binary TCs. In detail, a total of three binary TC cases over the Northwestern Pacific from 2010 to 2015, which affected the Korean Peninsula, were selected. Infrared and microwave radiance data from multiple instruments and satellites were assimilated with the appropriate treatments of quality control, channel selection, bias correction, and cloud detection. The Weather Research and Forecasting (WRF) model was used as a forecasting model, and the resolution of the innermost domain was high (2 km) to capture the structure and intensity of TCs. Background error covariance was calculated using the National Meteorological Center (NMC) method, where background error statistics were from the differences between 24-h and 12-h forecasts for a month-long period. Overall, track and intensity errors of three binary TCs are reduced through the assimilation of radiance data. Especially, track forecasts are improved significantly because large-scale environments such as the North Pacific High and mid-latitude trough/ridge are simulated well. Analysis increment and its evolution are investigated to reveal the reason for the improvement of each binary TC's forecast, focusing on TC's internal structure and its environment. Additionally, effects of other observational data (e.g. radiosonde, satellite wind) are analyzed through the sensitivity experiments.

  14. Lectin status, protein contents and ammonium assimilating ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... Lectin status, protein contents and ammonium assimilating enzymatic activity of two indigenous cultivars of mulberry species, Morus alba and Morus nigra. Muhammad Zahoor*, Zakia Javaid, Muhammad Ali, Saleem Khan, Farhad Ali and Zahoor A. Swati. Institute of Biotechnology and Genetic Engineering, ...

  15. Development of a data assimilation algorithm

    DEFF Research Database (Denmark)

    Thomsen, Per Grove; Zlatev, Zahari

    2008-01-01

    efficiently observations in a large-scale model (for example, in order to obtain more reliable initial values). Variational data assimilation techniques are based on a combination of three very important components • numerical methods for solving differential equations, • splitting procedures...

  16. On the Linguistic Covariants of Cultural Assimilation

    Science.gov (United States)

    T'sou, Benjamin K.

    1975-01-01

    This paper discusses diverse sociolinguistic concepts such as borrowing, code-switching, bilingualism, and interference, and proposes a hypothesis concerning the progression of these linguistic developments in a contact situation and concerning the correlation of these developments with distinct phases of cultural assimilation. (Author/CLK)

  17. Economic and Cultural Assimilation and Integration of Immigration in Europe

    OpenAIRE

    Mariya Aleksynska; Yann Algan

    2010-01-01

    This paper documents assimilation of immigrants in 16 European countries along cultural, civic, and economic dimensions, distinguishing by immigrants’ generation, duration of stay, and origin. It suggests that assimilation may have multiple facets, and take place at different speed depending on the outcome in question. While assimilation along some economic outcomes may be correlated with assimilation along some cultural outcomes, such correlations are not systematic, and imply that progress ...

  18. A flexible Open Data Assimilation framework

    Science.gov (United States)

    van Velzen, Nils; Ridler, Marc E.; Altaf, Umer; Madsen, Henrik; Heemink, Arnold; Dijkzeul, Johan

    2015-04-01

    Accurate and reliable real-time hydrological forecasts are essential for protection against water-related hazards, operation of infrastructure, and water resources management. Recent advances in radar rainfall estimation and forecasting, numerical weather predictions, satellite and in-situ monitoring, and faster computing facilities are opening up new opportunities in real-time hydrological forecasting. More effective use of the different information sources via data assimilation will provide the basis for producing more accurate and more reliable forecasts. In this regard, development and implementation of robust and computationally efficient data assimilation algorithms that are feasible for real-time applications remains one of the key challenges. The implementation of data assimilation techniques is traditionally in a model specific form. The disadvantage of this approach is the need to have in-depth knowledge of the numerical core computations and it does not allow to freely experiment with data assimilation algorithms and measurement sources without the need of additional programming. We present a more flexible approach to setup a forecasting system. The OpenDA data assimilation framework contains many state of the art data assimilation algorithms to easily set up a forecasting system. The setup of the framework allows users to select and experiment with various algorithms. OpenDA defines an interface between model and data assimilation algorithms. This interface only needs to be implemented once for a particular model. The OpenDA model interface is already implemented for various models. Besides these models it is very easy to couple models that are already implementing the Open Model Interface (OpenMI) to OpenDA using the generic OpenMI-OpenDA coupler. Using a synthetic test case we demonstrate the capabilities of the proposed approach using OpenMI and OpenDA. We use the MIKE SHE distributed and integrated hydrological modeling system to demonstrate how

  19. Estimation of friction parameters in gravity currents by data assimilation in a model hierarchy

    Directory of Open Access Journals (Sweden)

    A. Wirth

    2011-04-01

    Full Text Available This paper is the last in a series of three investigating the friction laws and their parametrisation in idealised gravity currents in a rotating frame. Results on the dynamics of a gravity current (Wirth, 2009 and on the estimation of friction laws by data assimilation (Wirth and Verron, 2008 are combined to estimate the friction parameters and discriminate between friction laws in non-hydrostatic numerical simulations of gravity current dynamics, using data assimilation and a reduced gravity shallow water model.

    I demonstrate, that friction parameters and laws in gravity currents can be estimated using data assimilation. The results clearly show that friction follows a linear Rayleigh law for small Reynolds numbers and the estimated value agrees well with the analytical value obtained for non-accelerating Ekman layers. A significant and sudden departure towards a quadratic drag law at an Ekman layer based Reynolds number of around 800 is shown, in agreement with classical laboratory experiments. The drag coefficient obtained compares well to friction values over smooth surfaces. I show that data assimilation can be used to determine friction parameters and discriminate between friction laws and that it is a powerful tool in systematically connecting models within a model hierarchy.

  20. Continuous data assimilation for downscaling large-footprint soil moisture retrievals

    KAUST Repository

    Altaf, Muhammad

    2016-01-01

    Soil moisture is a key component of the hydrologic cycle, influencing processes leading to runoff generation, infiltration and groundwater recharge, evaporation and transpiration. Generally, the measurement scale for soil moisture is found to be different from the modeling scales for these processes. Reducing this mismatch between observation and model scales in necessary for improved hydrological modeling. An innovative approach to downscaling coarse resolution soil moisture data by combining continuous data assimilation and physically based modeling is presented. In this approach, we exploit the features of Continuous Data Assimilation (CDA) which was initially designed for general dissipative dynamical systems and later tested numerically on the incompressible Navier-Stokes equation, and the Benard equation. A nudging term, estimated as the misfit between interpolants of the assimilated coarse grid measurements and the fine grid model solution, is added to the model equations to constrain the model\\'s large scale variability by available measurements. Soil moisture fields generated at a fine resolution by a physically-based vadose zone model (HYDRUS) are subjected to data assimilation conditioned upon coarse resolution observations. This enables nudging of the model outputs towards values that honor the coarse resolution dynamics while still being generated at the fine scale. Results show that the approach is feasible to generate fine scale soil moisture fields across large extents, based on coarse scale observations. Application of this approach is likely in generating fine and intermediate resolution soil moisture fields conditioned on the radiometerbased, coarse resolution products from remote sensing satellites.