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Min Wu, Ting Wan, Xiongbo Wan, Yuxiao Du, Jinhua She
This letter describes the improvement of two methods of detecting high-frequency oscillations (HFO) 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...
October 20, 2016: Neural Computation
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
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
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
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
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
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
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
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
Stephen V Gliske, William C Stacey, Kevin R Moon, Alfred O Hero
High frequency oscillations (HFOs) are a promising biomarker of epileptic brain tissue and activity. HFOs additionally serve as a prototypical example of challenges in the analysis of discrete events in high-temporal resolution, intracranial EEG data. Two primary challenges are 1) dimensionality reduction, and 2) assessing feasibility of classification. Dimensionality reduction assumes that the data lie on a manifold with dimension less than that of the features space. However, previous HFO analysis have assumed a linear manifold, global across time, space (i...
March 2016: Proceedings of the ... IEEE International Conference on Acoustics, Speech, and Signal Processing
Hisako Fujiwara, James L Leach, Hansel M Greiner, Katherine D Holland-Bouley, Douglas F Rose, Todd Arthur, Francesco T Mangano
Resective epilepsy surgery can improve seizures when the epileptogenic zone (EZ) is limited to a well-defined region. High frequency oscillations (HFO) have been recognized as having a high association with the seizure onset zone. Therefore, we retrospectively identified ictal HFOs and determined their relationship to specific intracranial features of cortical tubers in children with TSC who underwent resective surgery. We identified 14 patients with drug resistant epilepsy secondary to TSC who underwent subdural grid and strip implantation for presurgical evaluation and subsequent resection with adequate post-surgical follow-up...
October 2016: Epilepsy Research
Keith R Solomon, Guus J M Velders, Stephen R Wilson, Sasha Madronich, Janice Longstreth, Pieter J Aucamp, Janet F Bornman
Trifluoroacetic acid (TFA) is a breakdown product of several hydrochlorofluorocarbons (HCFC), regulated under the Montreal Protocol (MP), and hydrofluorocarbons (HFC) used mainly as refrigerants. Trifluoroacetic acid is (1) produced naturally and synthetically, (2) used in the chemical industry, and (3) a potential environmental breakdown product of a large number (>1 million) chemicals, including pharmaceuticals, pesticides, and polymers. The contribution of these chemicals to global amounts of TFA is uncertain, in contrast to that from HCFC and HFC regulated under the MP...
June 28, 2016: Journal of Toxicology and Environmental Health. Part B, Critical Reviews
Miguel Navarrete, Catalina Alvarado-Rojas, Michel Le Van Quyen, Mario Valderrama
High Frequency Oscillations (HFOs) in the brain have been associated with different physiological and pathological processes. In epilepsy, HFOs might reflect a mechanism of epileptic phenomena, serving as a biomarker of epileptogenesis and epileptogenicity. Despite the valuable information provided by HFOs, their correct identification is a challenging task. A comprehensive application, RIPPLELAB, was developed to facilitate the analysis of HFOs. RIPPLELAB provides a wide range of tools for HFOs manual and automatic detection and visual validation; all of them are accessible from an intuitive graphical user interface...
2016: PloS One
Bin-Ke Yuan, Yu-Feng Zang, Dong-Qiang Liu
High-frequency oscillations (HFOs, >0.1 Hz) of resting-state fMRI (rs-fMRI) signals have received much attention in recent years. Denoising is critical for HFO studies. Previous work indicated that head motion (HM) has remarkable influences on a variety of rs-fMRI metrics, but its influences on rs-fMRI HFOs are still unknown. In this study, we investigated the impacts of HM regression (HMR) on HFO results using a fast sampling rs-fMRI dataset. We demonstrated that apparent high-frequency (∼0.2-0.4 Hz) components existed in the HM trajectories in almost all subjects...
2016: Frontiers in Human Neuroscience
Ida A Nissen, Nicole E C van Klink, Maeike Zijlmans, Cornelis J Stam, Arjan Hillebrand
OBJECTIVE: Previous studies have associated network hubs and epileptiform activity, such as spikes and high frequency oscillations (HFOs), with the epileptogenic zone. The epileptogenic zone is approximated by the area that generates interictal epileptiform activity: the irritative zone. Our aim was to determine the relation between network hubs and the irritative zone. METHODS: Interictal resting-state MEG recordings of 12 patients with refractory epilepsy were analysed...
July 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Christian Endisch, Gunnar Waterstraat, Christian Storm, Christoph J Ploner, Gabriel Curio, Christoph Leithner
OBJECTIVE: Following cardiac arrest (CA), hypoxic encephalopathy (HE) frequently occurs and hence reliable neuroprognostication is crucial to decide on the extent of intensive care. Several investigations predict severe HE leading to persistent unresponsive wakefulness or death, with high specificity. Only few studies attempted to predict absence of severe HE. Cortical somatosensory evoked high-frequency (600Hz) oscillation (HFO) bursts indicate the presence of highly synchronized spiking activity in the primary somatosensory cortex...
July 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Stefan Fuertinger, Kristina Simonyan, Michael R Sperling, Ashwini D Sharan, Farid Hamzei-Sichani
OBJECTIVE: Cortical high-frequency oscillations (HFOs; 100-500 Hz) play a critical role in the pathogenesis of epilepsy; however, whether they represent a true epileptogenic process remains largely unknown. HFOs have been recorded in the human cortex but their network dynamics during the transitional period from interictal to ictal phase remain largely unknown. We sought to determine the high-frequency network dynamics of these oscillations in patients with epilepsy who were undergoing intracranial electroencephalographic recording for seizure localization...
July 2016: Epilepsia
Nicolás von Ellenrieder, Birgit Frauscher, François Dubeau, Jean Gotman
OBJECTIVE: To characterize the interaction between physiologic and pathologic high-frequency oscillations (HFOs) and slow waves during sleep, and to evaluate the practical significance of these interactions by automatically classifying channels as recording from normal or epileptic brain regions. METHODS: We automatically detected HFOs in intracerebral electroencephalography (EEG) recordings of 45 patients. We characterized the interaction between the HFOs and the amplitude and phase of automatically detected slow waves during sleep...
June 2016: Epilepsia
Yutaka Nonoda, Makoto Miyakoshi, Alejandro Ojeda, Scott Makeig, Csaba Juhász, Sandeep Sood, Eishi Asano
OBJECTIVE: High-frequency oscillations (HFOs) can be spontaneously generated by seizure-onset and functionally-important areas. We determined if consideration of the spectral frequency bands of coupled slow-waves could distinguish between epileptogenic and physiological HFOs. METHODS: We studied a consecutive series of 13 children with focal epilepsy who underwent extraoperative electrocorticography. We measured the occurrence rate of HFOs during slow-wave sleep at each electrode site...
June 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Massimo Avoli, Marco de Curtis, Vadym Gnatkovsky, Jean Gotman, Rüdiger Köhling, Maxime Lévesque, Frédéric Manseau, Zahra Shiri, Sylvain Williams
Low-voltage fast (LVF) and hypersynchronous (HYP) patterns are the seizure-onset patterns most frequently observed in intracranial EEG recordings from mesial temporal lobe epilepsy (MTLE) patients. Both patterns also occur in models of MTLE in vivo and in vitro, and these studies have highlighted the predominant involvement of distinct neuronal network/neurotransmitter receptor signaling in each of them. First, LVF-onset seizures in epileptic rodents can originate from several limbic structures, frequently spread, and are associated with high-frequency oscillations in the ripple band (80-200 Hz), whereas HYP onset seizures initiate in the hippocampus and tend to remain focal with predominant fast ripples (250-500 Hz)...
June 1, 2016: Journal of Neurophysiology
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