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Intracranial EEG

Bo Jin, Wenhan Hu, Linmei Ye, Balu Krishnan, Thandar Aung, Stephen E Jones, Imad M Najm, Andreas V Alexopoulos, Kai Zhang, Junming Zhu, Jianguo Zhang, Meiping Ding, Zhong Chen, Shuang Wang, Zhong Irene Wang
Objective: To investigate the neuroimaging and clinical features associated with sleep-related epilepsy (SRE) in patients with focal cortical dysplasia (FCD) type II. Methods: Patients with histopathologically proven FCD type II were included from three epilepsy centers. SRE was defined according to the video EEG findings and seizure history. Cortical surface reconstruction and volume calculation were performed using FreeSurfer. The lesions were manually delineated on T1 volumetric MRI using the ITK-SNAP software...
2018: Frontiers in Neurology
Firas Bannout, Sheri Harder, Michael Lee, Alexander Zouros, Ravi Raghavan, Travis Fogel, Kenneth De Los Reyes, Travis Losey
The neurosurgical treatment of skull base temporal encephalocele for patients with epilepsy is variable. We describe two adult cases of temporal lobe epilepsy (TLE) with spheno-temporal encephalocele, currently seizure-free for more than two years after anterior temporal lobectomy (ATL) and lesionectomy sparing the hippocampus without long-term intracranial electroencephalogram (EEG) monitoring. Encephaloceles were detected by magnetic resonance imaging (MRI) and confirmed by maxillofacial head computed tomography (CT) scans...
March 12, 2018: Brain Sciences
Fatemeh Khadjevand, Jan Cimbalnik, Gregory A Worrell
High-frequency oscillations (HFOs: 100 - 600 Hz) have been widely proposed as biomarkers of epileptic brain tissue. In addition, HFOs over a broader range of frequencies spanning 30 - 2000 Hz are potential biomarkers of both physiological and pathological brain processes. The majority of the results from humans with focal epilepsy have focused on HFOs recorded directly from the brain with intracranial EEG (iEEG) in the high gamma (65 - 100 Hz), ripple (100 - 250 Hz), and fast ripple (250 - 600 Hz) frequency ranges...
December 2017: Current Opinion in Biomedical Engineering
Christopher S Parker, Jonathan D Clayden, M Jorge Cardoso, Roman Rodionov, John S Duncan, Catherine Scott, Beate Diehl, Sebastien Ourselin
Patients with medically-refractory focal epilepsy may be candidates for neurosurgery and some may require placement of intracranial EEG electrodes to localise seizure onset. Assessing cerebral responses to single pulse electrical stimulation (SPES) may give diagnostically useful data. SPES produces cortico-cortical evoked potentials (CCEPs), which infer effective brain connectivity. Diffusion-weighted images and tractography may be used to estimate structural brain connectivity. This combination provides the opportunity to observe seizure onset and its propagation throughout the brain, spreading contiguously along the cortex explored with electrodes, or non-contiguously...
2018: NeuroImage: Clinical
Josef Parvizi, Sabine Kastner
Intracranial electroencephalography (iEEG), also known as electrocorticography when using subdural grid electrodes or stereotactic EEG when using depth electrodes, is blossoming in various fields of human neuroscience. In this article, we highlight the potentials of iEEG in exploring functions of the human brain while also considering its limitations. The iEEG signal provides anatomically precise information about the selective engagement of neuronal populations at the millimeter scale and the temporal dynamics of their engagement at the millisecond scale...
March 5, 2018: Nature Neuroscience
Birgit Frauscher, Nicolas von Ellenrieder, Rina Zelmann, Irena Doležalová, Lorella Minotti, André Olivier, Jeffery Hall, Dominique Hoffmann, Dang Khoa Nguyen, Philippe Kahane, François Dubeau, Jean Gotman
In contrast to scalp EEG, our knowledge of the normal physiological intracranial EEG activity is scarce. This multicentre study provides an atlas of normal intracranial EEG of the human brain during wakefulness. Here we present the results of power spectra analysis during wakefulness. Intracranial electrodes are placed in or on the brain of epilepsy patients when candidates for surgical treatment and non-invasive approaches failed to sufficiently localize the epileptic focus. Electrode contacts are usually in cortical regions showing epileptic activity, but some are placed in normal regions, at distance from the epileptogenic zone or lesion...
March 1, 2018: Brain: a Journal of Neurology
Anna Witkowska-Wrobel, Kirill Aristovich, Mayo Faulkner, James Avery, David Holder
Imaging ictal and interictal activity with Electrical Impedance Tomography (EIT) using intracranial electrode mats has been demonstrated in animal models of epilepsy. In human epilepsy subjects undergoing presurgical evaluation, depth electrodes are often preferred. The purpose of this work was to evaluate the feasibility of using EIT to localise epileptogenic areas with intracranial electrodes in humans. The accuracy of localisation of the ictal onset zone was evaluated in computer simulations using 9M element FEM models derived from three subjects...
February 27, 2018: NeuroImage
Mitsuyo Nishimura, Tohru Okanishi, Ayataka Fujimoto, Sotaro Kanai, Yuki Sasaki, Yoichiro Homma, Hiroshi Otsubo, Hideo Enoki
OBJECTIVE: Ictal scalp EEG patterns have been reported to vary across onset regions. We assessed the sequential EEG changes during seizure events on scalp EEG, and tested our hypothesis that patients with focal seizures arising from the cortex facing the interhemispheric fissure (IHF cortex) would be specifically characterized by 3 phase-EEG patterns (3Ph-EEG). METHODS: Patient inclusion criteria were: 1) focal epilepsy and 2) ictal onset records on scalp and intracranial video-EEG...
February 20, 2018: Epilepsy Research
Martin Völker, Lukas D J Fiederer, Sofie Berberich, Jiří Hammer, Joos Behncke, Pavel Kršek, Martin Tomášek, Petr Marusič, Peter C Reinacher, Volker A Coenen, Moritz Helias, Andreas Schulze-Bonhage, Wolfram Burgard, Tonio Ball
Error detection in motor behavior is a fundamental cognitive function heavily relying on cortical information processing. Neural activity in the high-gamma frequency band (HGB) closely reflects such local cortical processing, but little is known about its role in error processing, particularly in the healthy human brain. Here we characterize the error-related response of the human brain based on data obtained with noninvasive EEG optimized for HGB mapping in 31 healthy subjects (15 females, 16 males), and additional intracranial EEG data from 9 epilepsy patients (4 females, 5 males)...
February 19, 2018: NeuroImage
Ying Chen, Weihai Xu, Lijuan Wang, Xiaoming Yin, Jie Cao, Fang Deng, Yingqi Xing, Jiachun Feng
BACKGROUND: Neurological deterioration after intracerebral hemorrhage (ICH) is thought to be closely related to increased intracranial pressure (ICP), decreased cerebral blood flow (CBF), and brain metabolism. Transcranial Doppler (TCD) is increasingly used as an indirect measure of ICP, and quantitative EEG (QEEG) can reflect the coupling of CBF and metabolism. We aimed to combine TCD and QEEG to comprehensively assess brain function after ICH and provide prognostic diagnosis. METHODS: We prospectively enrolled patients with severe acute supratentorial (SAS)-ICH from June 2015 to December 2016...
February 20, 2018: Critical Care: the Official Journal of the Critical Care Forum
Aashit K Shah, Darren Fuerst, Sandeep Mittal
OBJECTIVE: Relationship between electrographic seizures on hippocampal electrocorticography (IH-ECoG) and presence/type of hippocampal pathology remains unclear. METHODS: IH-ECoG was recorded for 10-20 min from the ventricular surface of the hippocampus following removal of the temporal neocortex in 40 consecutive patients. Correlation between intraoperative hippocampal seizures and preoperative MRI, hippocampal histopathology, and EEG from invasive monitoring was determined...
February 2, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
D M Mateos, R Guevara Erra, R Wennberg, J L Perez Velazquez
Quantification of complexity in neurophysiological signals has been studied using different methods, especially those from information or dynamical system theory. These studies have revealed a dependence on different states of consciousness, and in particular that wakefulness is characterized by a greater complexity of brain signals, perhaps due to the necessity for the brain to handle varied sensorimotor information. Thus, these frameworks are very useful in attempts to quantify cognitive states. We set out to analyze different types of signals obtained from scalp electroencephalography (EEG), intracranial EEG and magnetoencephalography recording in subjects during different states of consciousness: resting wakefulness, different sleep stages and epileptic seizures...
February 2018: Cognitive Neurodynamics
Hannah C Glass
PURPOSE OF REVIEW: Neonatal encephalopathy is the most common condition in neonates encountered by child neurologists. The etiology is most often global hypoxia-ischemia due to failure of cerebral perfusion to the fetus caused by uterine, placental, or umbilical cord compromise prior to or during delivery. Other etiologies of neonatal encephalopathy include ischemic stroke and intracranial hemorrhage, infection, developmental anomalies, and inborn errors of metabolism. RECENT FINDINGS: Therapeutic hypothermia is standard of care for the treatment of neonatal encephalopathy presumed to be caused by hypoxia-ischemia...
February 2018: Continuum: Lifelong Learning in Neurology
Josephine Cruzat, Gustavo Deco, Adrià Tauste-Campo, Alessandro Principe, Albert Costa, Morten L Kringelbach, Rodrigo Rocamora
Cognitive processing requires the ability to flexibly integrate and process information across large brain networks. How do brain networks dynamically reorganize to allow broad communication between many different brain regions in order to integrate information? We record neural activity from 12 epileptic patients using intracranial EEG while performing three cognitive tasks. We assess how the functional connectivity between different brain areas changes to facilitate communication across them. At the topological level, this facilitation is characterized by measures of integration and segregation...
February 6, 2018: NeuroImage
Michal T Kucewicz, Brent M Berry, Vaclav Kremen, Laura R Miller, Fatemeh Khadjevand, Youssef Ezzyat, Joel M Stein, Paul Wanda, Michael R Sperling, Richard Gorniak, Kathryn A Davis, Barbara C Jobst, Robert E Gross, Bradley Lega, S Matt Stead, Daniel S Rizzuto, Michael J Kahana, Gregory A Worrell
Direct electrical stimulation of the brain has emerged as a powerful treatment for multiple neurological diseases, and as a potential technique to enhance human cognition. Despite its application in a range of brain disorders, it remains unclear how stimulation of discrete brain areas affects memory performance and the underlying electrophysiological activities. Here, we investigated the effect of direct electrical stimulation in four brain regions known to support declarative memory: hippocampus (HP), parahippocampal region (PH) neocortex, prefrontal cortex (PF), and lateral temporal cortex (TC)...
January 2018: ENeuro
Su Liu, Candan Gurses, Zhiyi Sha, Michael M Quach, Altay Sencer, Nerses Bebek, Daniel J Curry, Sujit Prabhu, Sudhakar Tummala, Thomas R Henry, Nuri F Ince
High-frequency oscillations in local field potentials recorded with intracranial EEG are putative biomarkers of seizure onset zones in epileptic brain. However, localized 80-500 Hz oscillations can also be recorded from normal and non-epileptic cerebral structures. When defined only by rate or frequency, physiological high-frequency oscillations are indistinguishable from pathological ones, which limit their application in epilepsy presurgical planning. We hypothesized that pathological high-frequency oscillations occur in a repetitive fashion with a similar waveform morphology that specifically indicates seizure onset zones...
January 30, 2018: Brain: a Journal of Neurology
Gonzalo Alarcón, Diego Jiménez-Jiménez, Antonio Valentín, David Martín-López
OBJECTIVES: To model cortical connections in order to characterize their oscillatory behavior and role in the generation of spontaneous electroencephalogram (EEG). METHODS: We studied averaged responses to single pulse electrical stimulation (SPES) from the non-epileptogenic hemisphere of five patients assessed with intracranial EEG who became seizure free after contralateral temporal lobectomy. Second-order control system equations were modified to characterize the systems generating a given response...
November 23, 2017: International Journal of Neural Systems
Arturo G Sámano, José D Ochoa Mena, Silvana P Padilla, Gerardo R Acevedo, José M Orenday Barraza, Daniel San-Juan
PURPOSE: The purpose of this study was to describe the characteristics and preferences of clinical neurophysiology (CN) fellows, as well as the resources available for their training, in a developing country such as Mexico. METHODS: An online survey (25 questions) was given to Mexican CN fellows from May to June 2017, covering their reasons for choosing the CN subspecialty, their activities, future plans, institutional resources, and administrative staff. Descriptive statistics were used...
January 23, 2018: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
Hari Guragain, Jan Cimbalnik, Matt Stead, David M Groppe, Brent M Berry, Vaclav Kremen, Daniel Kenney-Jung, Jeffrey Britton, Gregory A Worrell, Benjamin H Brinkmann
OBJECTIVE: To assess the variation in baseline and seizure onset zone interictal high-frequency oscillation (HFO) rates and amplitudes across different anatomic brain regions in a large cohort of patients. METHODS: Seventy patients who had wide-bandwidth (5 kHz) intracranial EEG (iEEG) recordings during surgical evaluation for drug-resistant epilepsy between 2005 and 2014 who had high-resolution MRI and CT imaging were identified. Discrete HFOs were identified in 2-hour segments of high-quality interictal iEEG data with an automated detector...
February 20, 2018: Neurology
Adam C Snyder, Deepa Issar, Matthew A Smith
Long-range interactions between cortical areas are undoubtedly a key to the computational power of the brain. For healthy human subjects, the premier method for measuring brain activity on fast timescales is electroencephalography (EEG), and coherence between EEG signals is often used to assay functional connectivity between different brain regions. However, the nature of the underlying brain activity that is reflected in EEG coherence is currently the realm of speculation, because seldom have EEG signals been recorded simultaneously with intracranial recordings near cell bodies in multiple brain areas...
January 24, 2018: European Journal of Neuroscience
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