scholarly journals The Epileptogenic Zone: Concept and Definition

2018 ◽  
Vol 18 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Lara Jehi
Keyword(s):  
Common Ground ◽  
Focal Epilepsy ◽  
Epileptogenic Zone ◽  
Single Individual ◽  
Drug Resistant ◽  
The Past ◽  
Definition Of ◽  
The Mind ◽  
Specific Definition ◽  
The Ideal

A “concept” refers to what exists in the mind as a representation (as in something comprehended) or as a formulation (as in a plan). It is generally understood as “any idea of what a thing ought to be” (Merriam-Webster). From that premise, an “idea” cannot be compartmentalized or rigidly defined as exclusively belonging to any single individual or school of thought. The utility of a concept is inherently linked to its adaptability to the needs and conditions of the time. I state this upfront because over the past several decades, the concept of the epileptogenic zone (EZ) has become so crucial to the foundation of major schools of surgical epilepsy that discussions and opinions on the topic have essentially sought to legitimize one view while criticizing the other. This review is not a referendum on any specific definition of the EZ but rather a chronological analysis of the historical evolution of this concept and the invasive EEG tools used to study it. The goal is to highlight common ground necessary to tackle the ever-present challenge of defining the ideal resection for a patient with drug-resistant focal epilepsy.

Can Groups Assert That P?

2019 ◽  
pp. 326-344
Author(s):  
Deborah Tollefsen
Keyword(s):  
Common Ground ◽  
Speech Act ◽  
Single Individual ◽  
Constitutive Rule ◽  
The Past ◽  
Group Members ◽  
The Common ◽  
Declarative Statement ◽  
John Macfarlane

When a group or institution issues a declarative statement, what sort of speech act is this? Is it the assertion of a single individual (perhaps the group’s spokesperson or leader) or the assertion of all or most of the group members? Or is there a sense in which the group itself asserts that p? If assertion is a speech act, then who is the actor in the case of group assertion? These are the questions this chapter aims to address. Whether groups themselves can make assertions or whether a group of individuals can jointly assert that p depends, in part, on what sort of speech act assertion is. The literature on assertion has burgeoned over the past few years, and there is a great deal of debate regarding the nature of assertion. John MacFarlane has helpfully identified four theories of assertion. Following Sandy Goldberg, we can call these the attitudinal account, the constitutive rule account, the common-ground account, and the commitment account. I shall consider what group assertion might look like under each of these accounts and doing so will help us to examine some of the accounts of group assertion (often presented as theories of group testimony) on offer. I shall argue that, of the four accounts, the commitment account can best be extended to make sense of group assertion in all its various forms.

scholarly journals Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation (SEEG-Guided RF-TC) in Patients with Drug-Resistant Focal Epilepsy

2017 ◽  
Vol 3 (1) ◽  
pp. 40-47
Author(s):  
Chengwei Xu ◽  
Wenjing Zhou
Keyword(s):  
Radio Frequency ◽  
Surgical Resection ◽  
Seizure Frequency ◽  
Palliative Treatment ◽  
Focal Epilepsy ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Functional Area ◽  
Presurgical Evaluation ◽  
Epileptic Patients

For some patients with drug-resistant focal epilepsy, we usually select conventional surgical resection, which has brought better outcomes. However, others are not eligible for a conventional open surgical resection of the epileptogenic zone because of the proximity of a functional area or the implication of a larger epileptogenic network. Initially, stereoelectroencephalography (SEEG) exploration was a method of electroencephalography recording that was used in the presurgical evaluation of epileptic patients with complex epilepsy. Later, intracerebral electrodes used for SEEG were applied to produce radio frequency thermocoagulation (RF-TC) in epileptic patients. SEEG-guided RF-TC has produced some promising results, especially in the last dacade. Now, it has become popular as a palliative treatment to reduce seizure frequency in patients with drug-resistant focal epilepsy. This article presents a review of SEEG-guided RF-TC.

scholarly journals Value of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation in treating drug-resistant focal epilepsy

2019 ◽  
Vol 5 (3) ◽  
pp. 189-202
Author(s):  
Jianjun Bai ◽  
Wenjing Zhou ◽  
Haixiang Wang ◽  
Bingqing Zhang ◽  
Jiuluan Lin ◽  
...  
Keyword(s):  
Refractory Epilepsy ◽  
Focal Epilepsy ◽  
Intractable Epilepsy ◽  
Epileptogenic Zone ◽  
Presurgical Evaluation ◽  
The Past ◽  
Limited Efficacy ◽  
Radiofrequency Thermocoagulation ◽  
Temporary Treatment ◽  
Promising Treatment

Stereoelectroencephalography (SEEG) has been widely used in the presurgical evaluation of patients with medically intractable epilepsy. In the past, SEEG was commonly used as a method for mapping and localizing the epileptogenic zone (EZ). Since 2004, several studies have been conducted to examine the effectiveness of SEEG-guided radiofrequency thermocoagulation (RF-TC) in treating refractory epilepsy. However, the seizure-free and responder rates varied greatly across studies. We aimed to analyze the outcome of 56 patients who were treated with SEEG-guided RF-TC to evaluate the effectiveness of this treatment. SEEG-guided RF-TC can be considered as a treatment for refractory epilepsy. However, due to its limited efficacy, SEEG-guided RF-TC might be regarded as a temporary treatment performed under SEEG rather than a promising treatment for refractory epilepsy.

scholarly journals Terminology as a key uncertainty in net land use and land cover change carbon flux estimates

2014 ◽  
Vol 5 (1) ◽  
pp. 177-195 ◽  
Author(s):  
J. Pongratz ◽  
C. H. Reick ◽  
R. A. Houghton ◽  
J. I. House
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Flux ◽  
Scientific Application ◽  
The Past ◽  
Different Types ◽  
Definition Of ◽  
Specific Definition ◽  
Terminological Confusion

Abstract. Reasons for the large uncertainty in land use and land cover change (LULCC) emissions go beyond recognized issues related to the available data on land cover change and the fact that model simulations rely on a simplified and incomplete description of the complexity of biological and LULCC processes. The large range across published LULCC emission estimates is also fundamentally driven by the fact that the net LULCC flux is defined and calculated in different ways across models. We introduce a conceptual framework that allows us to compare the different types of models and simulation setups used to derive land use fluxes. We find that published studies are based on at least nine different definitions of the net LULCC flux. Many multi-model syntheses lack a clear agreement on definition. Our analysis reveals three key processes that are accounted for in different ways: the land use feedback, the loss of additional sink capacity, and legacy (regrowth and decomposition) fluxes. We show that these terminological differences, alone, explain differences between published net LULCC flux estimates that are of the same order as the published estimates themselves. This has consequences for quantifications of the residual terrestrial sink: the spread in estimates caused by terminological differences is conveyed to those of the residual sink. Furthermore, the application of inconsistent definitions of net LULCC flux and residual sink has led to double-counting of fluxes in the past. While the decision to use a specific definition of the net LULCC flux will depend on the scientific application and potential political considerations, our analysis shows that the uncertainty of the net LULCC flux can be substantially reduced when the existing terminological confusion is resolved.

scholarly journals Role of Repetitive Transcranial Magnetic Stimulation on Drug Resistant Focal Epilepsy: A Controlled Clinical Study

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
S Ashour ◽  
A Gaber ◽  
T Hussein ◽  
A Kamal
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Focal Epilepsy ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Baseline Period ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Resting Motor Threshold ◽  
Before And After

Abstract Copyright 2019 Department of Neuropsychiatry, Ain Shams University. Unauthorized reproduction of this article is prohibited Purpose This study was designed to evaluate the therapeutic effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on patients with drug resistant focal epilepsy. Methods Fifty-five patients with drug resistant neocortical focal epilepsy were screened and 30 patients were divided into two groups (active and sham ) were given (0.5 hz , 1000 pulses , 90%of resting motor threshold (rMT)) on stimulation site detected by correlation between clinical semiology, EEG and or MRI finding. Seizures frequency, severity and seizure free days were compared for one month before and after rTMS with no change in antiepileptic drugs. We assumed 50% seizure reductionrate after rTMS. Results Seizures significantly decreased following rTMS treatment 50% seizure reduction was achieved 87.5%inthe active rTMS groupand50% in the sham rTMS group(p > 0.03).in the follow-up period compared to baseline period. Seizure free days %increase in active group 20.7% compared to sham group 7.5% (p = 0.0501). Significance Low-frequency rTMS delivered into the epileptogenic zone had a significant antiepileptic effect on patients with drug resistant neocortical focal epilepsy. © 2018 Department of Neuropsychiatry, Ain Shams University

Imagination and Education

2021 ◽  
Author(s):  
Moira von Wright
Keyword(s):  
Common Ground ◽  
Central Element ◽  
Human Beings ◽  
Way Of Life ◽  
Social Imagination ◽  
Meaning Creation ◽  
Definition Of ◽  
The Relationship ◽  
Self Formation ◽  
Specific Definition

The concept of imagination, with its potential to contribute to education, is attracting increasing interest as humanity faces major challenges such as migration and climate change. Imagination is expected to enlarge the mentality of human beings and help to find new solutions to global problems. However, educational thinkers have different understandings of what imagination and imaginative thought can actually contribute to. Imagination is the mental ability to visualize what may lie beyond the immediate situation and to “see” things that are not present. It is a central element of meaning creation in education—in the relationship between mental pictures and reality, between humans and the outside world, and between the past and the future. Imagination is a way of seeing, a happening in the here and now. No single specific definition of imagination exists, and this term is used in a variety of ways. Because it is so evasive, the idea of imagination has been contested and questioned, so its meaning depends on the theory and context with which it is associated. Many educational theories simply neglect the concept of imagination, or limit its meaning to common fantasizing and playfulness, whereas others give imagination a central role in the processes of understanding and learning. The socially and politically emancipating dimension of imagination has been emphasized, as has its moral significance and relation to self-formation and education. Some thinkers argue that education should not be satisfied with developing students’ ability to think imaginatively, create a narrative and develop social imagination; rather, it needs to intentionally raise young people to “live imaginatively”—that is, to live a rich life with an open mind, being ready to think in new ways and change their habits when former ways of thinking prove untenable for moral and ethical reasons. Despite these differences of opinion, the value of imagination in education is undeniable. Yet questions remain: How does “bad fantasy” differ from “good imagination,” and what are the educational consequences of such a distinction? How can imagination be a common ground in education, and how can it be a liminal space or topos for the different perspectives of children and adults in that area? How can imagination be part of a greater social responsibility and a way of life?

scholarly journals The importance of situated language use for aphasia rehabilitation

2018 ◽  
Author(s):  
Willemijn Josefien Doedens ◽  
Lotte Meteyard
Keyword(s):  
Language Impairment ◽  
Language Use ◽  
Common Ground ◽  
Systematic Approach ◽  
Traditional Approach ◽  
Behaviour Therapy ◽  
The Past ◽  
Communicative Ability ◽  
Definition Of ◽  
Linguistic Phenomenon

There is a growing realization that the traditional approach to studying language, i.e. as a decontextualized,linguistic phenomenon, does not allow us to fully understand communication in the real world. Bystudying the way people process words and sentences in isolation, a wealth of variables that play a role innaturalistic communication are missed. In the study of aphasia, a language impairment caused by acquiredbrain damage such as stroke, a thorough understanding of the mechanisms of naturalistic communicationis imperative, as this is the behaviour therapy aims to improve. The field of aphasiology currently lacksa comprehensive, theoretically founded definition of communication. This lack of understanding, we willargue, makes it nearly impossible to accurately describe a person’s level of communicative ability in everydaylife as well as to predict with certainty what kind of intervention will lead to a change at the levelof communication. In this article we propose a model of situated language use borrowed from sociology,psychology, communication sciences and psycholinguistics, which covers both internal (e.g. individual) andexternal (e.g. environmental) factors that influence communication, including the traditional linguisticskills that have been extensively researched in the past. The model defines language use as: (1) interactive,(2) multimodal, and (3) based on context (common ground). An extensive review of existing researchon each component of the model in non-brain damaged adults and people with aphasia is provided. Theconsequences of adopting this approach to diagnosis and therapy for aphasia are discussed. The aim of thisarticle is to encourage a more systematic approach to the study of situated language use in aphasia.

Simultaneous Frame-assisted Stereotactic Placement of Subdural Grid Electrodes and Intracerebral Depth Electrodes

2019 ◽  
Vol 80 (05) ◽  
pp. 353-358 ◽  
Author(s):  
Peter C. Reinacher ◽  
Dirk-Matthias Altenmüller ◽  
Marie T. Krüger ◽  
Andreas Schulze-Bonhage ◽  
Horst Urbach ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Surgical Time ◽  
Depth Electrodes ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
Intracranial Electrodes ◽  
Complex Cases

Background and Study Aims In complex cases of drug-resistant focal epilepsy, the precise localization of the epileptogenic zone requires simultaneous implantation of depth and subdural grid electrodes. This study describes a new simple frame-assisted method that facilitates the simultaneous placement of both types of intracranial electrodes. Material and Methods Ten consecutive patients were evaluated and divided into two groups. Group A included patients with simultaneous frame-assisted placement of depth and subdural grid electrodes. In group B, depth electrodes were implanted stereotactically; grid electrodes were implanted in a separate surgery. Results The placement of the subdural grid was accurate as individually designed by the epileptologists in all five patients from group A. In group B, one patient showed a slight and another one a significant deviation of the subdural grid position postoperatively. The mean surgical time in group A was shorter (280±62 minutes) compared with the mean duration of the surgical procedures in group B (336±51 minutes). Conclusion The frame-assisted placement of subdural grid electrodes facilitates the surgical procedure for invasive video-electroencephalography monitoring in complex cases of drug-resistant focal epilepsy in which a combination of depth electrodes and subdural grid electrodes is needed, by reducing the surgical time and guaranteeing highly accurate electrode localizations.

scholarly journals Localizing Epileptogenic Zone from High Density EEG Data Using Machine Learning

2021 ◽  
Vol 17 (06) ◽  
pp. 73
Author(s):  
Sehresh Khan ◽  
Aunsia Khan ◽  
Nazia Hameed ◽  
Muhammad Aleem Taufiq ◽  
Saba Riaz
Keyword(s):  
Machine Learning ◽  
Human Brain ◽  
Antiepileptic Drugs ◽  
Focal Epilepsy ◽  
Brain Regions ◽  
High Density ◽  
Machine Learning Algorithms ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Time Frequency

<span>Drug-resistant focal epilepsy is the failure of antiepileptic drugs scheduled to obtain epileptic free brain activities. In human brain, cerebral hemispheres are the most commonly involved brain regions in epilepsy. In case of antiepileptic drugs failure, surgical treatment is the best cure possible. However, correct localization of epileptogenic region is a challenging task for neurologists, while for computer scientists, automatic localization is. This research work’s aim is to explore the functional activities of all brain regions in drug-resistant focal epileptic patients and achieve high accuracy for the classification of epileptogenic region (ER) with the high-density electroencephalographic (hdEEG) data. The proposed system includes frequency analysis for feature extractions followed by individual subject’s registration of hdEEG signals with anatomical brain images for most precise localization of ER possible. The datasets attained from feature extraction process are then preprocessed for class imbalanced and then evaluated using different machine learning algorithms including the techniques under Bayesian networks, Lazy networks, Meta techniques, Rule based systems and Tree structured algorithms. Considering human brain as stationary object as well as dynamic object, frequency-based and time-frequency based features were considered in 12 subjects respectively. Through this novel approach, 99.70% accuracy is achieved to classify ER from healthy regions using KSTAR and using IBK algorithm, 91.60% accuracy has been achieved to classify generator from propagator.</span>

Stereoelectroencephalography in the presurgical evaluation of focal epilepsy in infancy and early childhood

2012 ◽  
Vol 9 (3) ◽  
pp. 290-300 ◽  
Author(s):  
Massimo Cossu ◽  
Marco Schiariti ◽  
Stefano Francione ◽  
Dalila Fuschillo ◽  
Francesca Gozzo ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Brain Mri ◽  
Electrode Placement ◽  
Motor Deficit ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Presurgical Evaluation ◽  
Intracranial Surgery ◽  
Eloquent Areas ◽  
Drug Resistant Epilepsy

Object The authors report on the use of stereoelectroencephalography (stereo-EEG) in the presurgical electroclinical evaluation of infants and very young children with focal drug-resistant epilepsy. Methods Fifteen patients (9 girls and 6 boys, mean age 34.1 ± 7.3 months, range 21–45 months), potentially candidates to receive surgical treatment for their focal drug-resistant epilepsy, were evaluated using stereo-EEG recording for a detailed definition of the epileptogenic zone. Stereoelectroencephalography was indicated because neuroradiological (brain MRI) and video-EEG data failed to adequately localize the epileptogenic zone. Stereotactic placement of multicontact intracerebral electrodes was preceded by the acquisition of all pertinent anatomical information from structural and functional MRI and from brain angiography, enabling the accurate targeting of desired structures through avascular trajectories. Stereoelectroencephalography monitoring attempted to record habitual seizures; electrical stimulations were performed to induce seizures and for the functional mapping of eloquent areas. Stereoelectroencephalography-guided microsurgery, when indicated, pointed to removal of the epileptogenic zone and seizure control. Results Brain MRI revealed an anatomical lesion in 13 patients (lobar in 2 cases, multilobar or hemispheric in 11 cases) and was unremarkable in 2 patients. One patient underwent 2 stereo-EEG studies. The arrangement of the intracerebral electrodes was unilateral in all but 1 case. One patient died the day following electrode placement due to massive brain edema and profound hyponatremia of undetermined cause. In 8 cases intracerebral electrical stimulations allowed mapping of functionally critical areas; in 3 other cases that received purposeful placement of electrodes in presumably eloquent areas, no functional response was obtained. Of the 14 patients who completed stereo-EEG monitoring, 1 was excluded from surgery for multifocality of seizures and 13 underwent operations. Postoperatively, 2 patients exhibited an anticipated, permanent motor deficit, 3 experienced a transient motor deficit, and 2 experienced transient worsening of a preexisting motor deficit. Three patients developed a permanent homonymous hemianopia after posterior resections. Histological analysis revealed cortical malformations in 10 cases. Of the 10 patients with a postoperative follow-up of at least 12 months, 6 (60%) were seizure-free (Engel Class Ia), 2 (20%) experienced a significant reduction of seizures (Engel Class II), and 2 (20%) were unchanged (Engel Class IV). Conclusions The present study indicates that stereo-EEG plays a prominent role in the presurgical evaluation of focal epilepsies also in the first years of life and that it may offer a surgical option in particularly complex cases that would have scarcely benefitted from further medical treatment. Results of stereo-EEG–guided resective surgery were excellent, with 80% of patients exhibiting a substantial improvement in seizures. In consideration of the potentially life-threatening risks of major intracranial surgery in this specific age group, the authors recommend reserving stereo-EEG evaluations for infants with realistic chances of benefiting from surgery.

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