1
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Quon RJ, Meisenhelter S, Camp EJ, Testorf ME, Song Y, Song Q, Culler GW, Moein P, Jobst BC. AiED: Artificial intelligence for the detection of intracranial interictal epileptiform discharges. Clin Neurophysiol 2021; 133:1-8. [PMID: 34773796 DOI: 10.1016/j.clinph.2021.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/02/2021] [Accepted: 09/21/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Deep learning provides an appealing solution for the ongoing challenge of automatically classifying intracranial interictal epileptiform discharges (IEDs). We report results from an automated method consisting of a template-matching algorithm and convolutional neural network (CNN) for the detection of intracranial IEDs ("AiED"). METHODS 1000 intracranial electroencephalogram (EEG) epochs extracted randomly from 307 subjects with refractory epilepsy were annotated independently by two expert neurophysiologists. These annotated epochs were divided into 1062 two-second epochs with IEDs and 1428 two-second epochs without IEDs, which were transformed into spectrograms prior to training the neural network. The highest performing network was validated on an annotated external test set. RESULTS The final network had an F1-score of 0.95 (95% CI: 0.91-0.98) and an average Area Under the Receiver Operating Characteristic of 0.98 (95% CI: 0.96-1.00). For the external test set, it showed an overall F1-score of 0.71, correctly identifying 100% of all high-amplitude IED complexes, 96.23% of all high-amplitude isolated IEDs, and 66.15% of all IEDs of atypical morphology. CONCLUSIONS Template-matching combined with a CNN offers a fast, robust method for detecting intracranial IEDs. SIGNIFICANCE "AiED" is generalizable and achieves comparable performance to human reviewers; it may support clinical and research EEG analyses.
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Affiliation(s)
- Robert J Quon
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Department of Quantitative Biomedical Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
| | | | - Edward J Camp
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
| | - Markus E Testorf
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA; Thayer School of Engineering at Dartmouth College, Hanover, NH, USA.
| | - Yinchen Song
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
| | - Qingyuan Song
- Department of Quantitative Biomedical Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
| | - George W Culler
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
| | - Payam Moein
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
| | - Barbara C Jobst
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
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2
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Saboo KV, Balzekas I, Kremen V, Varatharajah Y, Kucewicz M, Iyer RK, Worrell GA. Leveraging electrophysiologic correlates of word encoding to map seizure onset zone in focal epilepsy: Task-dependent changes in epileptiform activity, spectral features, and functional connectivity. Epilepsia 2021; 62:2627-2639. [PMID: 34536230 DOI: 10.1111/epi.17067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Verbal memory dysfunction is common in focal, drug-resistant epilepsy (DRE). Unfortunately, surgical removal of seizure-generating brain tissue can be associated with further memory decline. Therefore, localization of both the circuits generating seizures and those underlying cognitive functions is critical in presurgical evaluations for patients who may be candidates for resective surgery. We used intracranial electroencephalographic (iEEG) recordings during a verbal memory task to investigate word encoding in focal epilepsy. We hypothesized that engagement in a memory task would exaggerate local iEEG feature differences between the seizure onset zone (SOZ) and neighboring tissue as compared to wakeful rest ("nontask"). METHODS Ten participants undergoing presurgical iEEG evaluation for DRE performed a free recall verbal memory task. We evaluated three iEEG features in SOZ and non-SOZ electrodes during successful word encoding and compared them with nontask recordings: interictal epileptiform spike (IES) rates, power in band (PIB), and relative entropy (REN; a functional connectivity measure). RESULTS We found a complex pattern of PIB and REN changes in SOZ and non-SOZ electrodes during successful word encoding compared to nontask. Successful word encoding was associated with a reduction in local electrographic functional connectivity (increased REN), which was most exaggerated in temporal lobe SOZ. The IES rates were reduced during task, but only in the non-SOZ electrodes. Compared with nontask, REN features during task yielded marginal improvements in SOZ classification. SIGNIFICANCE Previous studies have supported REN as a biomarker for epileptic brain. We show that REN differences between SOZ and non-SOZ are enhanced during a verbal memory task. We also show that IESs are reduced during task in non-SOZ, but not in SOZ. These findings support the hypothesis that SOZ and non-SOZ respond differently to task and warrant further exploration into the use of cognitive tasks to identify functioning memory circuits and localize SOZ.
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Affiliation(s)
- Krishnakant V Saboo
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA.,Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine and Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota, USA
| | - Irena Balzekas
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine and Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota, USA
| | - Vaclav Kremen
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
| | - Yogatheesan Varatharajah
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois, Urbana, Illinois, USA
| | - Michal Kucewicz
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Faculty of Electronics, Telecommunications, and Informatics, Multimedia Systems Department, BioTechMed Center, Gdansk University of Technology, Gdansk, Poland.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Ravishankar K Iyer
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA
| | - Gregory A Worrell
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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3
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Musical components important for the Mozart K448 effect in epilepsy. Sci Rep 2021; 11:16490. [PMID: 34531410 PMCID: PMC8446029 DOI: 10.1038/s41598-021-95922-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/28/2021] [Indexed: 11/08/2022] Open
Abstract
There is growing evidence for the efficacy of music, specifically Mozart’s Sonata for Two Pianos in D Major (K448), at reducing ictal and interictal epileptiform activity. Nonetheless, little is known about the mechanism underlying this beneficial “Mozart K448 effect” for persons with epilepsy. Here, we measured the influence that K448 had on intracranial interictal epileptiform discharges (IEDs) in sixteen subjects undergoing intracranial monitoring for refractory focal epilepsy. We found reduced IEDs during the original version of K448 after at least 30-s of exposure. Nonsignificant IED rate reductions were witnessed in all brain regions apart from the bilateral frontal cortices, where we observed increased frontal theta power during transitions from prolonged musical segments. All other presented musical stimuli were associated with nonsignificant IED alterations. These results suggest that the “Mozart K448 effect” is dependent on the duration of exposure and may preferentially modulate activity in frontal emotional networks, providing insight into the mechanism underlying this response. Our findings encourage the continued evaluation of Mozart’s K448 as a noninvasive, non-pharmacological intervention for refractory epilepsy.
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4
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Quon RJ, Camp EJ, Meisenhelter S, Song Y, Steimel SA, Testorf ME, Andrew AS, Gross RE, Lega BC, Sperling MR, Kahana MJ, Jobst BC. Features of intracranial interictal epileptiform discharges associated with memory encoding. Epilepsia 2021; 62:2615-2626. [PMID: 34486107 DOI: 10.1111/epi.17060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Interictal epileptiform discharges (IEDs) were shown to be associated with cognitive impairment in persons with epilepsy. Previous studies indicated that IED rate, location, timing, and spatial relation to the seizure onset zone could predict an IED's impact on memory encoding and retrieval if they occurred in lateral temporal, mesial temporal, or parietal regions. In this study, we explore the influence that other IED properties (e.g., amplitude, duration, white matter classification) have on memory performance. We were specifically interested in investigating the influence that lateral temporal IEDs have on memory encoding. METHODS Two hundred sixty-one subjects with medication-refractory epilepsy undergoing intracranial electroencephalographic monitoring performed multiple sessions of a delayed free-recall task (n = 671). Generalized linear mixed models were utilized to examine the relationship between IED properties and memory performance. RESULTS We found that increased IED rate, IEDs propagating in white matter, and IEDs localized to the left middle temporal region were associated with poorer memory performance. For lateral temporal IEDs, we observed a significant interaction between IED white matter categorization and amplitude, where IEDs with an increased amplitude and white matter propagation were associated with reduced memory performance. Additionally, changes in alpha power after an IED showed a significant positive correlation with memory performance. SIGNIFICANCE Our results suggest that IED properties may be useful for predicting the impact an IED has on memory encoding. We provide an essential step toward understanding pathological versus potentially beneficial interictal epileptiform activity.
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Affiliation(s)
- Robert J Quon
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Edward J Camp
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Stephen Meisenhelter
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Yinchen Song
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Sarah A Steimel
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Markus E Testorf
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire, USA
| | - Angeline S Andrew
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, Georgia, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, Texas, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Barbara C Jobst
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
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5
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Li R, Plummer C, Vogrin SJ, Woods WP, Kuhlmann L, Boston R, Liley DTJ, Cook MJ, Grayden DB. Interictal spike localization for epilepsy surgery using magnetoencephalography beamforming. Clin Neurophysiol 2021; 132:928-937. [PMID: 33636608 DOI: 10.1016/j.clinph.2020.12.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/25/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Magnetoencephalography (MEG) kurtosis beamforming is an automated localization method for focal epilepsy. Visual examination of virtual sensors, which are source activities reconstructed by beamforming, can improve performance but can be time-consuming for neurophysiologists. We propose a framework to automate the method and evaluate its effectiveness against surgical resections and outcomes. METHODS We retrospectively analyzed MEG recordings of 13 epilepsy surgery patients who had one-year minimum post-operative follow-up. Kurtosis beamforming was applied and manual inspection was confined to morphological clusters. The region with the Maximum Interictal Spike Frequency (MISF) was validated against prospectively modelled sLORETA solutions and surgical resections linked to outcome. RESULTS Our approach localized spikes in 12 out of 13 patients. In eight patients with Engel I surgical outcomes, beamforming MISF regions were concordant with surgical resection at overlap level for five patients and at lobar level for three patients. The MISF regions localized to spike onset and propagation modelled by sLORETA in two and six patients, respectively. CONCLUSIONS Automated beamforming using MEG can predict postoperative seizure freedom at the lobar level but tends to localize propagated MEG spikes. SIGNIFICANCE MEG beamforming may contribute to non-invasive procedures to predict surgical outcome for patients with drug-refractory focal epilepsy.
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Affiliation(s)
- Rui Li
- Department of Biomedical Engineering, The University of Melbourne, Parkville, VIC, Australia.
| | - Chris Plummer
- Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Department of Neurology, St. Vincent's Hospital, Fitzroy, VIC, Australia; School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Simon J Vogrin
- Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Department of Neurology, St. Vincent's Hospital, Fitzroy, VIC, Australia; School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - William P Woods
- School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Levin Kuhlmann
- Faculty of Information Technology, Monash University, Clayton, VIC 3168, Australia
| | - Ray Boston
- Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Department of Clinical Studies, New Bolton Centre, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA
| | - David T J Liley
- Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Mark J Cook
- Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Department of Neurology, St. Vincent's Hospital, Fitzroy, VIC, Australia; Graeme Clark Institute for Biomedical Engineering, The University of Melbourne, Parkville, VIC, Australia
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Parkville, VIC, Australia; Department of Medicine, The University of Melbourne, Fitzroy, VIC, Australia; Graeme Clark Institute for Biomedical Engineering, The University of Melbourne, Parkville, VIC, Australia
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6
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Quon RJ, Meisenhelter S, Adamovich-Zeitlin RH, Song Y, Steimel SA, Camp EJ, Testorf ME, MacKenzie TA, Gross RE, Lega BC, Sperling MR, Kahana MJ, Jobst BC. Factors correlated with intracranial interictal epileptiform discharges in refractory epilepsy. Epilepsia 2020; 62:481-491. [PMID: 33332586 DOI: 10.1111/epi.16792] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVE This study was undertaken to evaluate the influence that subject-specific factors have on intracranial interictal epileptiform discharge (IED) rates in persons with refractory epilepsy. METHODS One hundred fifty subjects with intracranial electrodes performed multiple sessions of a free recall memory task; this standardized task controlled for subject attention levels. We utilized a dominance analysis to rank the importance of subject-specific factors based on their relative influence on IED rates. Linear mixed-effects models were employed to comprehensively examine factors with highly ranked importance. RESULTS Antiseizure medication (ASM) status, time of testing, and seizure onset zone (SOZ) location were the highest-ranking factors in terms of their impact on IED rates. The average IED rate of electrodes in SOZs was 34% higher than the average IED rate of electrodes outside of SOZs (non-SOZ; p < .001). However, non-SOZ electrodes had similar IED rates regardless of the subject's SOZ location (p = .99). Subjects on older generation (p < .001) and combined generation (p < .001) ASM regimens had significantly lower IED rates relative to the group taking no ASMs; newer generation ASM regimens demonstrated a nonsignificant association with IED rates (p = .13). Of the ASMs included in this study, the following ASMs were associated with significant reductions in IED rates: levetiracetam (p < .001), carbamazepine (p < .001), lacosamide (p = .03), zonisamide (p = .01), lamotrigine (p = .03), phenytoin (p = .03), and topiramate (p = .01). We observed a nonsignificant association between time of testing and IED rates (morning-afternoon p = .15, morning-evening p = .85, afternoon-evening p = .26). SIGNIFICANCE The current study ranks the relative influence that subject-specific factors have on IED rates and highlights the importance of considering certain factors, such as SOZ location and ASM status, when analyzing IEDs for clinical or research purposes.
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Affiliation(s)
- Robert J Quon
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Stephen Meisenhelter
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | | | - Yinchen Song
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Sarah A Steimel
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Edward J Camp
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Markus E Testorf
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire, USA
| | - Todd A MacKenzie
- Department of Biomedical Data Science, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Dartmouth Institute, Dartmouth College, Hanover, New Hampshire, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, Georgia, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, Texas, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Barbara C Jobst
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
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7
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Antiepileptic drugs induce subcritical dynamics in human cortical networks. Proc Natl Acad Sci U S A 2020; 117:11118-11125. [PMID: 32358198 DOI: 10.1073/pnas.1911461117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cortical network functioning critically depends on finely tuned interactions to afford neuronal activity propagation over long distances while avoiding runaway excitation. This importance is highlighted by the pathological consequences and impaired performance resulting from aberrant network excitability in psychiatric and neurological diseases, such as epilepsy. Theory and experiment suggest that the control of activity propagation by network interactions can be adequately described by a branching process. This hypothesis is partially supported by strong evidence for balanced spatiotemporal dynamics observed in the cerebral cortex; however, evidence of a causal relationship between network interactions and cortex activity, as predicted by a branching process, is missing in humans. Here this cause-effect relationship is tested by monitoring cortex activity under systematic pharmacological reduction of cortical network interactions with antiepileptic drugs. This study reports that cortical activity cascades, presented by the propagating patterns of epileptic spikes, as well as temporal correlations decline precisely as predicted for a branching process. The results provide a missing link to the branching process theory of cortical network function with implications for understanding the foundations of cortical excitability and its monitoring in conditions like epilepsy.
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8
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Seizure prediction and intervention. Neuropharmacology 2019; 172:107898. [PMID: 31839204 DOI: 10.1016/j.neuropharm.2019.107898] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/26/2019] [Accepted: 11/30/2019] [Indexed: 12/29/2022]
Abstract
Epilepsy treatment is challenging due to a lack of essential diagnostic tools, including methods for reliable seizure detection in the ambulatory setting, to assess seizure risk over time and to monitor treatment efficacy. This lack of objective diagnostics constitutes a significant barrier to better treatments, raises methodological concerns about the antiseizure medication evaluation process and, to patients, is a main issue contributing to the disease burden. Recent years have seen rapid progress towards better diagnostics that meet these needs of epilepsy patients and clinicians. Availability of comprehensive data and the rise of more powerful computational analysis methods have driven progress in this area. Here, we provide an overview on data- and theory-driven approaches aimed at identifying methods to reliably detect and forecast seizures as well as to monitor brain excitability and treatment efficacy in epilepsy. We provide a particular account on neural criticality, the hypothesis that cortical networks may be poised in a critical state at the boundary between different types of dynamics, and discuss its role in informing diagnostics to track cortex excitability and seizure risk in recent experiments. With the further expansion of digitalization in medicine, tele-medicine and long-term, ambulatory monitoring, these computationally based methods may gain more relevance in epilepsy in the future. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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9
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Kuhlmann L, Lehnertz K, Richardson MP, Schelter B, Zaveri HP. Seizure prediction - ready for a new era. Nat Rev Neurol 2019; 14:618-630. [PMID: 30131521 DOI: 10.1038/s41582-018-0055-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epilepsy is a common disorder characterized by recurrent seizures. An overwhelming majority of people with epilepsy regard the unpredictability of seizures as a major issue. More than 30 years of international effort have been devoted to the prediction of seizures, aiming to remove the burden of unpredictability and to couple novel, time-specific treatment to seizure prediction technology. A highly influential review published in 2007 concluded that insufficient evidence indicated that seizures could be predicted. Since then, several advances have been made, including successful prospective seizure prediction using intracranial EEG in a small number of people in a trial of a real-time seizure prediction device. In this Review, we examine advances in the field, including EEG databases, seizure prediction competitions, the prospective trial mentioned and advances in our understanding of the mechanisms of seizures. We argue that these advances, together with statistical evaluations, set the stage for a resurgence in efforts towards the development of seizure prediction methodologies. We propose new avenues of investigation involving a synergy between mechanisms, models, data, devices and algorithms and refine the existing guidelines for the development of seizure prediction technology to instigate development of a solution that removes the burden of the unpredictability of seizures.
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Affiliation(s)
- Levin Kuhlmann
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, Victoria, Australia.,Department of Medicine - St. Vincent's, The University of Melbourne, Parkville, Victoria, Australia.,Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Klaus Lehnertz
- Department of Epileptology, University of Bonn, Bonn, Germany. .,Interdisciplinary Center for Complex Systems, University of Bonn, Bonn, Germany.
| | - Mark P Richardson
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Björn Schelter
- Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen, UK
| | - Hitten P Zaveri
- Department of Neurology, Yale University, New Haven, CT, USA
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10
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Diamond JM, Chapeton JI, Theodore WH, Inati SK, Zaghloul KA. The seizure onset zone drives state-dependent epileptiform activity in susceptible brain regions. Clin Neurophysiol 2019; 130:1628-1641. [PMID: 31325676 DOI: 10.1016/j.clinph.2019.05.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 04/05/2019] [Accepted: 05/14/2019] [Indexed: 01/14/2023]
Abstract
OBJECTIVE Due to variability in the patterns of propagation of interictal epileptiform discharges (IEDs), qualitative definition of the irritative zone has been challenging. Here, we introduce a quantitative approach toward exploration of the dynamics of IED propagation within the irritative zone. METHODS We examined intracranial EEG (iEEG) in nine participants undergoing invasive monitoring for seizure localization. We used an automated IED detector and a community detection algorithm to identify populations of electrodes exhibiting IED activity that co-occur in time, and to group these electrodes into communities. RESULTS Within our algorithmically-identified communities, IED activity in the seizure onset zone (SOZ) tended to lead IED activity in other functionally coupled brain regions. The tendency of pathological activity to arise in the SOZ, and to spread to non-SOZ tissues, was greater in the asleep state. CONCLUSIONS IED activity, and, by extension, the variability observed between the asleep and awake states, is propagated from a core seizure focus to nearby less pathological brain regions. SIGNIFICANCE Using an unsupervised, computational approach, we show that the spread of IED activity through the epilepsy network varies with physiologic state.
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Affiliation(s)
- Joshua M Diamond
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, United States
| | - Julio I Chapeton
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, United States
| | - William H Theodore
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD 20892, United States
| | - Sara K Inati
- Epilepsy Service and EEG Section, NINDS, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, United States.
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11
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Janca R, Krsek P, Jezdik P, Cmejla R, Tomasek M, Komarek V, Marusic P, Jiruska P. The Sub-Regional Functional Organization of Neocortical Irritative Epileptic Networks in Pediatric Epilepsy. Front Neurol 2018; 9:184. [PMID: 29628910 PMCID: PMC5876241 DOI: 10.3389/fneur.2018.00184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/09/2018] [Indexed: 11/13/2022] Open
Abstract
Between seizures, irritative network generates frequent brief synchronous activity, which manifests on the EEG as interictal epileptiform discharges (IEDs). Recent insights into the mechanism of IEDs at the microscopic level have demonstrated a high variance in the recruitment of neuronal populations generating IEDs and a high variability in the trajectories through which IEDs propagate across the brain. These phenomena represent one of the major constraints for precise characterization of network organization and for the utilization of IEDs during presurgical evaluations. We have developed a new approach to dissect human neocortical irritative networks and quantify their properties. We have demonstrated that irritative network has modular nature and it is composed of multiple independent sub-regions, each with specific IED propagation trajectories and differing in the extent of IED activity generated. The global activity of the irritative network is determined by long-term and circadian fluctuations in sub-region spatiotemporal properties. Also, the most active sub-region co-localizes with the seizure onset zone in 12/14 cases. This study demonstrates that principles of recruitment variability and propagation are conserved at the macroscopic level and that they determine irritative network properties in humans. Functional stratification of the irritative network increases the diagnostic yield of intracranial investigations with the potential to improve the outcomes of surgical treatment of neocortical epilepsy.
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Affiliation(s)
- Radek Janca
- Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia
| | - Pavel Krsek
- Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czechia
| | - Petr Jezdik
- Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia
| | - Roman Cmejla
- Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia
| | - Martin Tomasek
- Department of Neurology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czechia
| | - Vladimir Komarek
- Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czechia
| | - Petr Marusic
- Department of Neurology, 2nd Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czechia
| | - Premysl Jiruska
- Department of Developmental Epileptology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czechia
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12
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Lambert I, Roehri N, Giusiano B, Carron R, Wendling F, Benar C, Bartolomei F. Brain regions and epileptogenicity influence epileptic interictal spike production and propagation during NREM sleep in comparison with wakefulness. Epilepsia 2017; 59:235-243. [PMID: 29205292 DOI: 10.1111/epi.13958] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Non-rapid eye movement (NREM) sleep is known to be a brain state associated with an activation of interictal epileptic activity. The goal of this work was to quantify topographic changes occurring during NREM sleep in comparison with wakefulness. METHOD We studied intracerebral recordings of 20 patients who underwent stereo-electroencephalography (SEEG) during presurgical evaluation for pharmacoresistant focal epilepsy. We measured the number of interictal spikes (IS) and quantified the co-occurrence of IS between brain regions during 1 hour of NREM sleep and 1 hour of wakefulness. Co-occurrence is a method to estimate IS networks based on a temporal concordance between IS of different brain regions. Each studied region was labeled as "seizure-onset zone" (SOZ), "propagation zone" (PZ), or "not involved region" (NIR). RESULTS During NREM sleep, the number of interictal spikes significantly increased in all regions (mean of 68%). This increase was higher in medial temporal regions than in other regions, whether involved in the SOZ. Spike co-occurrence increased significantly in all regions during NREM sleep in comparison with wakefulness but was greater in neocortical regions. Spike co-occurrence in medial temporal regions was not higher than in other regions, suggesting that the increase of the number of spikes in this region was in great part a local effect. SIGNIFICANCE This study demonstrated that medial temporal regions show a greater propensity to spike production or propagation during NREM sleep compared to other brain regions, even when the medial temporal lobe is not involved in the SOZ.
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Affiliation(s)
- Isabelle Lambert
- Inserm, INS, Institute of Neurosciences of Systems, Aix Marseille Univ, Marseille, France.,Clinical Neurophysiology, Timone Hospital, APHM, Marseille, France
| | - Nicolas Roehri
- Inserm, INS, Institute of Neurosciences of Systems, Aix Marseille Univ, Marseille, France
| | - Bernard Giusiano
- Inserm, INS, Institute of Neurosciences of Systems, Aix Marseille Univ, Marseille, France
| | - Romain Carron
- Functional and Stereotactic Neurosurgery, Timone Hospital, APHM, Marseille, France
| | | | - Christian Benar
- Inserm, INS, Institute of Neurosciences of Systems, Aix Marseille Univ, Marseille, France
| | - Fabrice Bartolomei
- Inserm, INS, Institute of Neurosciences of Systems, Aix Marseille Univ, Marseille, France.,Clinical Neurophysiology, Timone Hospital, APHM, Marseille, France
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13
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Ung H, Cazares C, Nanivadekar A, Kini L, Wagenaar J, Becker D, Krieger A, Lucas T, Litt B, Davis KA. Interictal epileptiform activity outside the seizure onset zone impacts cognition. Brain 2017; 140:2157-2168. [PMID: 28666338 DOI: 10.1093/brain/awx143] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 05/07/2017] [Indexed: 02/01/2023] Open
Abstract
See Kleen and Kirsch (doi:10.1093/awx178) for a scientific commentary on this article.Cognitive deficits are common among epilepsy patients. In these patients, interictal epileptiform discharges, also termed spikes, are seen routinely on electroencephalography and believed to be associated with transient cognitive impairments. In this study, we investigated the effect of spikes on memory encoding and retrieval, taking into account the spatial distribution of spikes in relation to the seizure onset zone as well as anatomical regions of the brain. Sixty-seven patients with medication refractory epilepsy undergoing continuous intracranial electroencephalography monitoring engaged in a delayed free recall task to test short-term memory. In this task, subjects were asked to memorize and recall lists of common nouns. We quantified the effect of each spike on the probability of successful recall using a generalized logistic mixed model. We found that in patients with left lateralized seizure onset zones, spikes outside the seizure onset zone impacted memory encoding, whereas those within the seizure onset zone did not. In addition, spikes in the left inferior temporal gyrus, middle temporal gyrus, superior temporal gyrus, and fusiform gyrus during memory encoding reduced odds of recall by as much as 15% per spike. Spikes also reduced the odds of word retrieval, an effect that was stronger with spikes outside of the seizure onset zone. These results suggest that seizure onset regions are dysfunctional at baseline, and support the idea that interictal spikes disrupt cognitive processes related to the underlying tissue.
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Affiliation(s)
- Hoameng Ung
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Christian Cazares
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ameya Nanivadekar
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lohith Kini
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Joost Wagenaar
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Danielle Becker
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Abba Krieger
- Department of Statistics, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian Litt
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn A Davis
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
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14
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Lévesque M, Salami P, Shiri Z, Avoli M. Interictal oscillations and focal epileptic disorders. Eur J Neurosci 2017. [DOI: 10.1111/ejn.13628] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Maxime Lévesque
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Pariya Salami
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Zahra Shiri
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
| | - Massimo Avoli
- Department of Neurology & Neurosurgery; Montreal Neurological Institute; McGill University; 3801 University Street Montréal QC Canada H3A 2B4
- Dipartimento di Medicina Sperimentale; Sapienza University of Rome; Roma Italy
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15
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Abou-Khalil B. The ambiguous relationship between spikes and seizures. Clin Neurophysiol 2016; 127:3176-3177. [PMID: 27401610 DOI: 10.1016/j.clinph.2016.06.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 06/20/2016] [Indexed: 01/11/2023]
Affiliation(s)
- Bassel Abou-Khalil
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA.
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16
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Goncharova II, Alkawadri R, Gaspard N, Duckrow RB, Spencer DD, Hirsch LJ, Spencer SS, Zaveri HP. The relationship between seizures, interictal spikes and antiepileptic drugs. Clin Neurophysiol 2016; 127:3180-3186. [PMID: 27292227 DOI: 10.1016/j.clinph.2016.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 05/01/2016] [Accepted: 05/16/2016] [Indexed: 01/09/2023]
Abstract
OBJECTIVE A considerable decrease in spike rate accompanies antiepileptic drug (AED) taper during intracranial EEG (icEEG) monitoring. Since spike rate during icEEG monitoring can be influenced by surgery to place intracranial electrodes, we studied spike rate during long-term scalp EEG monitoring to further test this observation. METHODS We analyzed spike rate, seizure occurrence and AED taper in 130 consecutive patients over an average of 8.9days (range 5-17days). RESULTS We observed a significant relationship between time to the first seizure, spike rate, AED taper and seizure occurrence (F (3,126)=19.77, p<0.0001). A high spike rate was related to a longer time to the first seizure. Further, in a subset of 79 patients who experienced seizures on or after day 4 of monitoring, spike rate decreased initially from an on- to off-AEDs epoch (from 505.0 to 382.3 spikes per hour, p<0.00001), and increased thereafter with the occurrence of seizures. CONCLUSIONS There is an interplay between seizures, spikes and AEDs such that spike rate decreases with AED taper and increases after seizure occurrence. SIGNIFICANCE The direct relationship between spike rate and AEDs and between spike rate and time to the first seizure suggests that spikes are a marker of inhibition rather than excitation.
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Affiliation(s)
- Irina I Goncharova
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Rafeed Alkawadri
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Nicolas Gaspard
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Robert B Duckrow
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Lawrence J Hirsch
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susan S Spencer
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Hitten P Zaveri
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.
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17
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Liu B, Li H, Gao C, Zhang Y, Wang C, Wu H, Dong S, Tao Y, Zhang H. Occurrence predictors of the temporal interictal epileptic discharges in epilepsy patients with extratemporal lesions: A prospective cohort study. Int J Surg 2016; 31:52-7. [PMID: 27216454 DOI: 10.1016/j.ijsu.2016.05.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 04/30/2016] [Accepted: 05/14/2016] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Electrical kindling models of epilepsy suggest that medial temporal structures are more prone to be irritated. The aim of this study is to investigate the occurrence rate of temporal interictal epileptic discharges (TIEDs) in the epilepsy patients with extratemporal lesions (ETLs), and to determine the predictive factors for TIEDs in this cohort. METHODS Totally 221 patients were admitted for presurgical evaluation, and focal ETL were found in all of them by MRI examination. The occurrence rates of TIEDs in several groups with different brain lobe locations, durations; of epilepsy, seizure frequencies, and onset ages stages were assessed. We also evaluated the surgical outcome of; resection in this cohort. RESULTS The total occurrence rate of TIEDs in this cohort was 29.9%. The occurrence rate of TIEDs in the patients with longer durations (>5 or 10 years) was significantly higher than those with shorter duration (<1 year). These; patients with lower seizure frequency (<1 seizure/month) had a significantly decreased incidence of TIEDs; compared with those with higher frequency (>1 seizure/month or week). In the terms of the brain lobe locations; and age at onset, there were no differences between the groups. Furthermore, there were no differences in terms of the surgical outcomes between the patients with TIEDs and other patients in this series. CONCLUSIONS TIEDs were frequently recorded in these patients with ETLs, and the predictive factors for TIEDs included the epilepsy duration and seizure frequency. SIGNIFICANCE This study is instrumental for the presurgical EEG interpretationand the counseling of these ETLs patients considered for epilepsy surgery.
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Affiliation(s)
- Bei Liu
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Huanfa Li
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Chen Gao
- Department of Neurosurgery, AnNing Branch Hospital, Lanzhou General Hospital, Lanzhou Command, Lanzhou, Gansu Province, China
| | - Yu Zhang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Chao Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Hao Wu
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Shan Dong
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Ye Tao
- Department of Ophthalmology, General Hospital of Chinese PLA, Ophthalmology & Visual Science Key Lab of PLA, Beijing, China.
| | - Hua Zhang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China.
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18
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Joshi RB, Gaspard N, Goncharova II, Pavlova M, Duckrow RB, Gerrard JL, Spencer DD, Hirsch LJ, Zaveri HP. Progressive change in sleep over multiple nights of intracranial EEG monitoring. Clin Neurophysiol 2016; 127:2302-7. [DOI: 10.1016/j.clinph.2016.02.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/31/2016] [Accepted: 02/23/2016] [Indexed: 12/17/2022]
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19
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Lesser RP. Small worlds. Clin Neurophysiol 2015; 126:221-2. [DOI: 10.1016/j.clinph.2014.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 06/16/2014] [Indexed: 11/30/2022]
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20
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Sleep affects cortical source modularity in temporal lobe epilepsy: A high-density EEG study. Clin Neurophysiol 2014; 126:1677-83. [PMID: 25666728 DOI: 10.1016/j.clinph.2014.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 12/04/2014] [Accepted: 12/05/2014] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Interictal epileptiform discharges (IEDs) constitute a perturbation of ongoing cerebral rhythms, usually more frequent during sleep. The aim of the study was to determine whether sleep influences the spread of IEDs over the scalp and whether their distribution depends on vigilance-related modifications in cortical interactions. METHODS Wake and sleep 256-channel electroencephalography (EEG) data were recorded in 12 subjects with right temporal lobe epilepsy (TLE) differentiated by whether they had mesial or neocortical TLE. Spikes were selected during wake and sleep. The averaged waking signal was subtracted from the sleep signal and projected on a bidimensional scalp map; sleep and wake spike distributions were compared by using a t-test. The superimposed signal of sleep and wake traces was obtained; the rising phase of the spike, the peak, and the deflections following the spike were identified, and their cortical generator was calculated using low-resolution brain electromagnetic tomography (LORETA) for each group. RESULTS A mean of 21 IEDs in wake and 39 in sleep per subject were selected. As compared to wake, a larger IED scalp projection was detected during sleep in both mesial and neocortical TLE (p<0.05). A series of EEG deflections followed the spike, the cortical sources of which displayed alternating activations of different cortical areas in wake, substituted by isolated, stationary activations in sleep in mesial TLE and a silencing in neocortical TLE. CONCLUSION During sleep, the IED scalp region increases, while cortical interaction decreases. SIGNIFICANCE The interaction of cortical modules in sleep and wake in TLE may influence the appearance of IEDs on scalp EEG; in addition, IEDs could be proxies for cerebral oscillation perturbation.
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21
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Gaspard N, Alkawadri R, Farooque P, Goncharova II, Zaveri HP. Automatic detection of prominent interictal spikes in intracranial EEG: validation of an algorithm and relationsip to the seizure onset zone. Clin Neurophysiol 2013; 125:1095-103. [PMID: 24269092 DOI: 10.1016/j.clinph.2013.10.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 10/21/2013] [Accepted: 10/27/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To develop an algorithm for the automatic quantitative description and detection of spikes in the intracranial EEG and quantify the relationship between prominent spikes and the seizure onset zone. METHODS An algorithm was developed for the quantification of time-frequency properties of spikes (upslope, instantaneous energy, downslope) and their statistical representation in a univariate generalized extreme value distribution. Its performance was evaluated in comparison to expert detection of spikes in intracranial EEG recordings from 10 patients. It was subsequently used in 18 patients to detect prominent spikes and quantify their spatial relationship to the seizure onset area. RESULTS The algorithm displayed an average sensitivity of 63.4% with a false detection rate of 3.2 per minute for the detection of individual spikes and an average sensitivity of 88.6% with a false detection rate of 1.4% for the detection of intracranial EEG contacts containing the most prominent spikes. Prominent spikes occurred closer to the seizure onset area than less prominent spikes but they overlapped with it only in a minority of cases (3/18). CONCLUSIONS Automatic detection and quantification of the morphology of spikes increases their utility to localize the seizure onset area. Prominent spikes tend to originate mostly from contacts located in the close vicinity of the seizure onset area rather than from within it. SIGNIFICANCE Quantitative analysis of time-frequency characteristics and spatial distribution of intracranial spikes provides complementary information that may be useful for the localization of the seizure-onset zone.
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Affiliation(s)
- Nicolas Gaspard
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA.
| | - Rafeed Alkawadri
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Pue Farooque
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Irina I Goncharova
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Hitten P Zaveri
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
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22
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On the nature of interictal epileptiform discharges. Clin Neurophysiol 2013; 124:2073-4. [DOI: 10.1016/j.clinph.2013.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 06/14/2013] [Indexed: 11/22/2022]
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