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https://www.readbyqxmd.com/read/28107659/high-frequency-oscillations-and-seizure-like-discharges-in-the-entorhinal-cortex-of-the-in-vitro-isolated-guinea-pig-brain
#1
Laura Uva, Davide Boido, Massimo Avoli, Marco de Curtis, Maxime Lévesque
We analyzed the patterns of seizure-like activity and associated high-frequency oscillations (HFOs) induced by the K(+) channel blocker 4-aminopyridine (4AP, 50μM) or the GABAA receptor antagonist bicuculline methiodide (BMI, 50μM) in the in vitro isolated guinea pig brain preparation. Extracellular field recordings were obtained from the medial entorhinal cortex (EC) using glass pipettes or silicon probes; 4AP or BMI were applied through the basilar artery. Ripples (80-200Hz) or fast ripples (250-500Hz) occurred at higher rates shortly before ictal events induced by 4AP or BMI, respectively...
January 6, 2017: Epilepsy Research
https://www.readbyqxmd.com/read/28063789/co-occurrence-of-high-frequency-oscillations-and-delayed-responses-evoked-by-intracranial-electrical-stimulation-in-stereo-eeg-studies
#2
Cristian Donos, Ioana Mîndruţă, Mihai Dragoş Malîia, Alin Raşină, Jean Ciurea, Andrei Barborica
OBJECTIVE: To perform a side-by-side comparison of two epileptogenicity biomarkers, high frequency oscillations (HFOs) and delayed responses (DRs), as a result of single-pulse electrical stimulation. METHODS: We have recorded stimulation-evoked HFOs and DRs in 16 epileptic patients undergoing presurgical evaluation using the stereoelectroencephalographic method. To evaluate converging and complementary information provided by the biomarkers, we analyzed them individually and for logical "and"/"or" combinations between them...
December 18, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28060325/interictal-high-frequency-oscillations-detected-with-simultaneous-magnetoencephalography-and-electroencephalography-as-biomarker-of-pediatric-epilepsy
#3
Christos Papadelis, Eleonora Tamilia, Steven Stufflebeam, Patricia E Grant, Joseph R Madsen, Phillip L Pearl, Naoaki Tanaka
Crucial to the success of epilepsy surgery is the availability of a robust biomarker that identifies the Epileptogenic Zone (EZ). High Frequency Oscillations (HFOs) have emerged as potential presurgical biomarkers for the identification of the EZ in addition to Interictal Epileptiform Discharges (IEDs) and ictal activity. Although they are promising to localize the EZ, they are not yet suited for the diagnosis or monitoring of epilepsy in clinical practice. Primary barriers remain: the lack of a formal and global definition for HFOs; the consequent heterogeneity of methodological approaches used for their study; and the practical difficulties to detect and localize them noninvasively from scalp recordings...
December 6, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28043201/physiological-ripples-associated-with-sleep-spindles-differ-in-waveform-morphology-from-epileptic-ripples
#4
Jonas C Bruder, Matthias Dümpelmann, Daniel Lachner Piza, Malenka Mader, Andreas Schulze-Bonhage, Julia Jacobs-Le Van
High frequency oscillations (HFOs, 80-500[Formula: see text]Hz) serve as novel electroencephalography (EEG) markers of epileptic tissue. The differentiation of physiological and epileptic HFO is an important challenge and is complicated by the fact that both types are generated in mesiotemporal structures. This study aimed to identify oscillation features that serve to distinguish physiological ripples associated with sleep spindles and epileptic ripples. We studied 19 patients with chronic intracranial EEG(iEEG) with mesiotemporal implantation and simultaneous scalp EEG...
November 2, 2016: International Journal of Neural Systems
https://www.readbyqxmd.com/read/27965619/dynamic-changes-in-spectral-and-spatial-signatures-of-high-frequency-oscillations-in-rat-hippocampi-during-epileptogenesis-in-acute-and-chronic-stages
#5
Pan-Pan Song, Jing Xiang, Li Jiang, Heng-Sheng Chen, Ben-Ke Liu, Yue Hu
OBJECTIVE: To analyze spectral and spatial signatures of high frequency oscillations (HFOs), which include ripples and fast ripples (FRs, >200 Hz) by quantitatively assessing average and peak spectral power in a rat model of different stages of epileptogenesis. METHODS: The lithium-pilocarpine model of temporal lobe epilepsy was used. The acute phase of epilepsy was assessed by recording intracranial electroencephalography (EEG) activity for 1 day after status epilepticus (SE)...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/27913322/automatic-detection-and-classification-of-high-frequency-oscillations-in-depth-eeg-signals
#6
Nisrine Jrad, Amar Kachenoura, Isabelle Merlet, Fabrice Bartolomei, Anca Nica, Arnaud Biraben, Fabrice Wendling
GOAL: Interictal High Frequency Oscillations (HFOs [30-600 Hz]) have proven to be relevant biomarkers in epilepsy. In this paper, four categories of HFOs are considered: Gamma ([30- 80 Hz]), High-Gamma ([80-120 Hz]), Ripples ([120-250 Hz]) and Fast-Ripples ([250-600 Hz]). A universal detector of the four types of HFOs is proposed. It has the advantages of i) classifying HFOs, and thus being robust to inter- and intra-subject variability; ii) rejecting artefacts, thus being specific. METHODS: Gabor atoms are tuned to cover the physiological bands...
November 29, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/27912169/non-harmonicity-in-high-frequency-components-of-the-intra-operative-corticogram-to-delineate-epileptogenic-tissue-during-surgery
#7
Evelien E Geertsema, Maryse A van 't Klooster, Nicole E C van Klink, Frans S S Leijten, Peter C van Rijen, Gerhard H Visser, Stiliyan N Kalitzin, Maeike Zijlmans
OBJECTIVE: We aimed to test the potential of auto-regressive model residual modulation (ARRm), an artefact-insensitive method based on non-harmonicity of the high-frequency signal, to identify epileptogenic tissue during surgery. METHODS: Intra-operative electrocorticography (ECoG) of 54 patients with refractory focal epilepsy were recorded pre- and post-resection at 2048Hz. The ARRm was calculated in one-minute epochs in which high-frequency oscillations (HFOs; fast ripples, 250-500Hz; ripples, 80-250Hz) and spikes were marked...
January 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27896067/relationship-between-high-frequency-oscillations-and-spikes-in-a-case-of-temporal-lobe-epilepsy
#8
Vishwanath Sagi, M Steven Evans
OBJECTIVE: The aim of this case report was to study the relationship between high-frequency oscillations (HFOs), spikes, and seizures in a patient with temporal lobe epilepsy. INTRODUCTION: During intracranial electroencephalography (EEG), HFOs are thought to be a marker for the seizure onset zone (SOZ). High-frequency oscillations are classified into ripples with frequencies of 70-200 Hz and fast ripples with frequencies of 200-500 Hz. Although HFOs are thought to be a marker for the SOZ, their relationship to spikes has not been studied in detail, especially within the SOZ...
2016: Epilepsy & Behavior Case Reports
https://www.readbyqxmd.com/read/27882298/high-frequency-oscillations-and-high-frequency-functional-network-characteristics-in-the-intraoperative-electrocorticogram-in-epilepsy
#9
W J E M Zweiphenning, M A van 't Klooster, E van Diessen, N E C van Klink, G J M Huiskamp, T A Gebbink, F S S Leijten, P H Gosselaar, W M Otte, C J Stam, K P J Braun, G J M Zijlmans
OBJECTIVE: High frequency oscillations (HFOs; > 80 Hz), especially fast ripples (FRs, 250-500 Hz), are novel biomarkers for epileptogenic tissue. The pathophysiology suggests enhanced functional connectivity within FR generating tissue. Our aim was to determine the relation between brain areas showing FRs and 'baseline' functional connectivity within EEG networks, especially in the high frequency bands. METHODS: We marked FRs, ripples (80-250 Hz) and spikes in the electrocorticogram of 14 patients with refractory temporal lobe epilepsy...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27875125/time-frequency-strategies-for-increasing-high-frequency-oscillation-detectability-in-intracerebral-eeg
#10
Nicolas Roehri, Jean-Marc Lina, John C Mosher, Fabrice Bartolomei, Christian-George Benar
BACKGROUND: High-frequency oscillations (HFOs) are considered to be highly representative of brain tissues capable of producing epileptic seizures. The visual review of HFOs on intracerebral electroencephalography is time consuming and tedious, and it can be improved by time-frequency (TF) analysis. The main issue is that the signal is dominated by lower frequencies that mask the HFOs. Our aim was to flatten (i.e., whiten) the frequency spectrum to enhance the fast oscillations while preserving an optimal signal to noise ratio (SNR)...
December 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/27861778/correlation-of-fdg-pet-hypometabolism-and-seeg-epileptogenicity-mapping-in-patients-with-drug-resistant-focal-epilepsy
#11
Florence Lamarche, Anne-Sophie Job, Pierre Deman, Manik Bhattacharjee, Dominique Hoffmann, Céline Gallazzini-Crépin, Sandrine Bouvard, Lorella Minotti, Philippe Kahane, Olivier David
OBJECTIVE: Interictal [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) is used in the presurgical evaluation of patients with drug-resistant focal epilepsy. We aimed at clarifying its relationships with ictal high-frequency oscillations (iHFOs) shown to be a relevant marker of the seizure-onset zone. METHODS: We studied the correlation between FDG-PET and epileptogenicity maps in an unselected series of 37 successive patients having been explored with stereo-electroencephalography (SEEG)...
December 2016: Epilepsia
https://www.readbyqxmd.com/read/27764594/fast-accurate-localization-of-epileptic-seizure-onset-zones-based-on-detection-of-high-frequency-oscillations-using-improved-wavelet-transform-and-matching-pursuit-methods
#12
Min Wu, Ting Wan, Xiongbo Wan, Yuxiao Du, Jinhua She
This letter describes the improvement of two methods of detecting high-frequency oscillations (HFOs) and their use to localize epileptic seizure onset zones (SOZs). The wavelet transform (WT) method was improved by combining the complex Morlet WT with Shannon entropy to enhance the temporal-frequency resolution during HFO detection. And the matching pursuit (MP) method was improved by combining it with an adaptive genetic algorithm to improve the speed and accuracy of the calculations for HFO detection. The HFOs detected by these two methods were used to localize SOZs in five patients...
January 2017: Neural Computation
https://www.readbyqxmd.com/read/27733815/gpi-oscillatory-activity-differentiates-tics-from-the-resting-state-voluntary-movements-and-the-unmedicated-parkinsonian-state
#13
Joohi Jimenez-Shahed, Ilknur Telkes, Ashwin Viswanathan, Nuri F Ince
Background: Deep brain stimulation (DBS) is an emerging treatment strategy for severe, medication-refractory Tourette syndrome (TS). Thalamic (Cm-Pf) and pallidal (including globus pallidus interna, GPi) targets have been the most investigated. While the neurophysiological correlates of Parkinson's disease (PD) in the GPi and subthalamic nucleus (STN) are increasingly recognized, these patterns are not well characterized in other disease states. Recent findings indicate that the cross-frequency coupling (CFC) between beta band and high frequency oscillations (HFOs) within the STN in PD patients is pathologic...
2016: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/27639348/high-frequency-oscillations-for-lateralizing-suspected-bitemporal-epilepsy
#14
Chunyan Liu, Ruihua Zhang, Guojun Zhang, Tao Yu, Junli Tai, Wei Du, Liping Li, Yuping Wang
OBJECTIVE: In some cases of single focus epilepsy, conventional video electroencephalography (EEG) cannot reveal the epileptogenic focus even when intracranial electrodes are used. Here, we tested whether analyzing high frequency oscillations (HFOs) can be used to determine the ictal onset zone in suspected bitemporal epilepsy and improve seizure outcome. METHODS: We prospectively studied 13 patients with refractory temporal seizures who were treated over a 4-year period and underwent bilateral placement of intracranial electrodes...
September 5, 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27635628/intracranial-eeg-seizure-onset-patterns-correlate-with-high-frequency-oscillations-in-patients-with-drug-resistant-epilepsy
#15
Taissa Ferrari-Marinho, Piero Perucca, Francois Dubeau, Jean Gotman
OBJECTIVE: High-frequency oscillations (80-500Hz; HFOs) have been shown to be a specific biomarker of the seizure-onset zone. The relationship of HFOs with seizures having different intracranial electroencephalography (iEEG) morphological onsets, however, has shown significant relationships in experimental animals but has not been studied in humans. We investigated how interictal and ictal HFOs relate to different seizure-onset morphological patterns. METHODS: We analyzed the most representative seizure type of 37 patients with drug-resistant focal epilepsy who underwent iEEG for diagnostic evaluation...
September 6, 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27579546/scalp-recorded-high-frequency-oscillations-in-atypical-benign-partial-epilepsy
#16
Ping Qian, Hui Li, Jiao Xue, Zhixian Yang
OBJECTIVE: To investigate how high-frequency oscillations (HFOs) were affected by methylprednisolone treatment and the clinical significance of HFOs in patients with atypical benign partial epilepsy (ABPE). METHODS: In 14 ABPE patients with methylprednisolone treatment, we measured interictal HFOs and spikes during sleep in pre- and post-methylprednisolone scalp electroencephalography (EEG). Patients with benign childhood epilepsy with centrotemporal spikes (BECTS) were taken as control...
October 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27517349/spontaneous-ripples-in-the-hippocampus-correlate-with-epileptogenicity-and-not-memory-function-in-patients-with-refractory-epilepsy
#17
Julia Jacobs, Sarah Banks, Rina Zelmann, Maeike Zijlmans, Marilyn Jones-Gotman, Jean Gotman
INTRODUCTION: High-frequency oscillations (HFOs, 80-500Hz) are newly-described EEG markers of epileptogenicity. The proportion of physiological and pathological HFOs is unclear, as frequency analysis is insufficient for separating the two types of events. For instance, ripples (80-250Hz) also occur physiologically during memory consolidation processes in medial temporal lobe structures. We investigated the correlation between HFO rates and memory performance. METHODS: Patients investigated with bilateral medial temporal electrodes and an intellectual capacity allowing for memory testing were included...
September 2016: Epilepsy & Behavior: E&B
https://www.readbyqxmd.com/read/27472542/automatic-detection-of-high-frequency-oscillations-during-epilepsy-surgery-predicts-seizure-outcome
#18
Tommaso Fedele, Maryse van 't Klooster, Sergey Burnos, Willemiek Zweiphenning, Nicole van Klink, Frans Leijten, Maeike Zijlmans, Johannes Sarnthein
OBJECTIVE: High frequency oscillations (HFOs) and in particular fast ripples (FRs) in the post-resection electrocorticogram (ECoG) have recently been shown to be highly specific predictors of outcome of epilepsy surgery. FR visual marking is time consuming and prone to observer bias. We validate here a fully automatic HFO detector against seizure outcome. METHODS: Pre-resection ECoG dataset (N=14 patients) with visually marked HFOs were used to optimize the detector's parameters in the time-frequency domain...
September 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27472539/effect-of-sampling-rate-and-filter-settings-on-high-frequency-oscillation-detections
#19
Stephen V Gliske, Zachary T Irwin, Cynthia Chestek, William C Stacey
OBJECTIVE: High Frequency Oscillations (HFOs) are being studied as a biomarker of epilepsy, yet it is unknown how various acquisition parameters at different centers affect detection and analysis of HFOs. This paper specifically quantifies effects of sampling rate (FS) and anti-aliasing filter (AAF) positions on automated HFO detection. METHODS: HFOs were detected on intracranial EEG recordings (17 patients) with 5kHz FS. HFO detection was repeated on downsampled and/or filtered copies of the EEG data, mimicking sampling rates and low-pass filter settings of various acquisition equipment...
September 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27456267/a-decrease-of-ripples-precedes-seizure-onset-in-mesial-temporal-lobe-epilepsy
#20
Cenglin Xu, Shuang Wang, Yi Wang, Kang Lin, Gang Pan, Zhenghao Xu, Jorge Gonzalez-Martinez, Feng Gao, Xiaohua Wu, Shihong Zhang, Juan C Bulacio, Imad M Najm, Jianhong Luo, Weiwei Hu, Zhaohui Wu, Norman K So, Zhong Chen
High-frequency oscillations (HFOs) are promising biomarkers for epileptic foci; however, their characteristic changes during the preictal period remain unclear. Here, the preictal HFOs were recorded and detected by an automated HFOs detection method in the mouse pilocarpine model as well as in patients with mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy. A total of sixteen low-voltage fast (LVF) and fifty-three hypersynchronous-onset (HYP) seizures were recorded in ten mice. The rate of ripples (80-250Hz) decreased during 1min before the onset of LVF and HYP seizures, which was primarily due to the reduction of type II (independent of epileptiform discharges) rather than type I ripples (superimposed on epileptiform activities)...
July 22, 2016: Experimental Neurology
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