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Khuvis S, Hwang ST, Mehta AD. Intracranial EEG Biomarkers for Seizure Lateralization in Rapidly-Bisynchronous Epilepsy After Laser Corpus Callosotomy. Front Neurol 2021; 12:696492. [PMID: 34690909 PMCID: PMC8531267 DOI: 10.3389/fneur.2021.696492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: It has been asserted that high-frequency analysis of intracranial EEG (iEEG) data may yield information useful in localizing epileptogenic foci. Methods: We tested whether proposed biomarkers could predict lateralization based on iEEG data collected prior to corpus callosotomy (CC) in three patients with bisynchronous epilepsy, whose seizures lateralized definitively post-CC. Lateralization data derived from algorithmically-computed ictal phase-locked high gamma (PLHG), high gamma amplitude (HGA), and low-frequency (filtered) line length (LFLL), as well as interictal high-frequency oscillation (HFO) and interictal epileptiform discharge (IED) rate metrics were compared against ground-truth lateralization from post-CC ictal iEEG. Results: Pre-CC unilateral IEDs were more frequent on the more-pathologic side in all subjects. HFO rate predicted lateralization in one subject, but was sensitive to detection threshold. On pre-CC data, no ictal metric showed better predictive power than any other. All post-corpus callosotomy seizures lateralized to the pathological hemisphere using PLHG, HGA, and LFLL metrics. Conclusions: While quantitative metrics of IED rate and ictal HGA, PHLG, and LFLL all accurately lateralize based on post-CC iEEG, only IED rate consistently did so based on pre-CC data. Significance: Quantitative analysis of IEDs may be useful in lateralizing seizure pathology. More work is needed to develop reliable techniques for high-frequency iEEG analysis.
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Affiliation(s)
- Simon Khuvis
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States.,Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, United States
| | - Sean T Hwang
- Department of Neurology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States
| | - Ashesh D Mehta
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States.,Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, United States
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2
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Swarup O, Waxmann A, Chu J, Vogrin S, Lai A, Laing J, Barker J, Seiderer L, Ignatiadis S, Plummer C, Carne R, Seneviratne U, Cook M, Murphy M, D'Souza W. Long-term mood, quality of life, and seizure freedom in intracranial EEG epilepsy surgery. Epilepsy Behav 2021; 123:108241. [PMID: 34450387 DOI: 10.1016/j.yebeh.2021.108241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To determine the long-term outcomes in patients undergoing intracranial EEG (iEEG) evaluation for epilepsy surgery in terms of seizure freedom, mood, and quality of life at St. Vincent's Hospital, Melbourne. METHODS Patients who underwent iEEG between 1999 and 2016 were identified. Patients were retrospectively assessed between 2014 and 2017 by specialist clinic record review and telephone survey with standardized validated questionnaires for: 1) seizure freedom using the Engel classification; 2) Mood using the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E); 3) Quality-of-life outcomes using the QOLIE-10 questionnaire. Summary statistics and univariate analysis were performed to investigate variables for significance. RESULTS Seventy one patients underwent iEEG surgery: 49 Subdural, 14 Depths, 8 Combination with 62/68 (91.9%) of those still alive, available at last follow-up by telephone survey or medical record review (median of 8.2 years). The estimated epileptogenic zone was 62% temporal and 38% extra-temporal. At last follow-up, 69.4% (43/62) were Engel Class I and 30.6% (19/62) were Engel Class II-IV. Further, a depressive episode (NDDI-E > 15)was observed in 34% (16/47), while a 'better quality of life' (QOLIE-10 score < 25) was noted in 74% (31/42). Quality of life (p < 0.001) but not mood (p = 0.24) was associated with seizure freedom. SIGNIFICANCE Long-term seizure freedom can be observed in patients undergoing complex epilepsy surgery with iEEG evaluation and is associated with good quality of life.
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Affiliation(s)
- Oshi Swarup
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia; Department of Medicine, Royal Melbourne Hospital, 300 Grattan Street, Parkville, Melbourne, Victoria 3050, Australia.
| | - Alexandra Waxmann
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia
| | - Jocelyn Chu
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Simon Vogrin
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia; Faculty of Health Arts and Design, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia
| | - Alan Lai
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia
| | - Joshua Laing
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - James Barker
- The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia; Department of Medicine, Royal Melbourne Hospital, 300 Grattan Street, Parkville, Melbourne, Victoria 3050, Australia
| | - Linda Seiderer
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Sophia Ignatiadis
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Chris Plummer
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia; Faculty of Health Arts and Design, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia
| | - Ross Carne
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Udaya Seneviratne
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia; Department of Neurosciences, Monash Medical Centre, 246 Clayton Rd, Clayton, Victoria 3168, Australia
| | - Mark Cook
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia
| | - Michael Murphy
- Department of Surgery, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Wendyl D'Souza
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia; The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia
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Seto ES, Coorg R. Epilepsy Surgery: Monitoring and Novel Surgical Techniques. Neurol Clin 2021; 39:723-742. [PMID: 34215384 DOI: 10.1016/j.ncl.2021.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Drug-resistant epilepsy warrants referral to an epilepsy surgery center for consideration of alternative treatments including epilepsy surgery. Advances in technology now allow for minimally invasive neurophysiologic monitoring and surgical interventions, approaches that are attractive to families because large craniotomies and associated morbidity are avoided. This work reviews the presurgical evaluation process and discusses the use of invasive stereo-electroencephalography monitoring to localize seizure onset zones. Minimally invasive surgical techniques are described for the treatment of focal and generalized epilepsies. These approaches have expanded our capacity to palliate and cure epilepsy in the pediatric population.
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Affiliation(s)
- Elaine S Seto
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Department of Neurology and Developmental Neuroscience, Texas Children's Hospital, 6701 Fannin Street, Suite 1250, Houston, TX 77030, USA.
| | - Rohini Coorg
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Department of Neurology and Developmental Neuroscience, Texas Children's Hospital, 6701 Fannin Street, Suite 1250, Houston, TX 77030, USA
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Jabran Y, Mahmoudzadeh M, Martinez N, Heberlé C, Wallois F, Bourel-Ponchel E. Temporal and Spatial Dynamics of Different Interictal Epileptic Discharges: A Time-Frequency EEG Approach in Pediatric Focal Refractory Epilepsy. Front Neurol 2020; 11:941. [PMID: 33013634 PMCID: PMC7506028 DOI: 10.3389/fneur.2020.00941] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/20/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: Characterization of the spatial and temporal dynamics of interictal epileptic discharges (IED) using time-frequency analysis (TFA) and electrical-source localization (ESL). Methods: TFA was performed on IED (spikes, spike waves, and polyspike waves) recorded by high-density-EEG (HD-EEG) in 19 refractory focal epileptic children. Temporal modulations related to IEDs were analyzed in a time window around the IED peaks [−1,000 to 1,000 ms]. Spatial modulations were analyzed by ESL in the time-frequency and time domains. Results: IED were associated with complex power spectral modulations. We observed increases in power spectrum (IPS) patterns specific to IED type. For spikes, the TFA pattern consisted of an IPS (−100 to +100 ms, 4–50 Hz). For spike waves, the IPS was followed by a second IPS (+100 to +400 ms, 4–10 Hz), corresponding to the slow wave. IPS patterns were preceded (−400 to −100 ms, 4–40 Hz), and followed (+100 to +400 ms) by a decrease in the power spectrum (DPS) (n = 8). For 14 out of 19 patients, at least one ESL method was concordant with the epileptogenic area. For the remaining five patients, all of them had temporal epilepsies. ESL in the time-frequency domain (DPS/IPS) provided concordant (n = 6) or complementary (n = 4) information to the ESL in the time domain concerning the epileptogenic zone. ESL in time-frequency domain (DPS/IPS) was the only method to provide concordant information concerning the epileptogenic zone in three patients. Significance: TFA demonstrates complex time-frequency modulations of the neuronal networks around IED, suggesting that the pathological mechanisms are initiated well before onset of the classical hyper-synchronization of the IED. Combining time and time-frequency analysis of the ESL provides complementary information to define the epileptogenic zone in refractory focal epilepsy.
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Affiliation(s)
- Younes Jabran
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
| | - Mahdi Mahmoudzadeh
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
| | - Nicolas Martinez
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France
| | - Claire Heberlé
- INSERM UMR 1105, Pediatric Neurophysiology Unit, Amiens University Hospital, Amiens, France
| | - Fabrice Wallois
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France.,INSERM UMR 1105, Pediatric Neurophysiology Unit, Amiens University Hospital, Amiens, France
| | - Emilie Bourel-Ponchel
- INSERM UMR 1105, Research Group on Multimodal Analysis of Brain Function, University of Picardie Jules Verne, Amiens, France.,INSERM UMR 1105, Pediatric Neurophysiology Unit, Amiens University Hospital, Amiens, France
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5
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Job AS, David O, Minotti L, Bartolomei F, Chabardès S, Kahane P. Epileptogenicity Maps of Intracerebral Fast Activities (60-100 Hz) at Seizure Onset in Epilepsy Surgery Candidates. Front Neurol 2019; 10:1263. [PMID: 31849823 PMCID: PMC6892969 DOI: 10.3389/fneur.2019.01263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 11/13/2019] [Indexed: 11/13/2022] Open
Abstract
Fast activities (FA) at seizure onset have been increasingly described as a useful signature of the epileptogenic zone (EZ) in patients undergoing intracranial EEG recordings. Different computer-based signal analysis methods have thus been developed for objectively quantifying ictal FA. Whether these methods detect FA in all forms of focal epilepsies, whether they provide similar information than visual analysis (VA), and whether they might help for the surgical decision remain crucial issues. We thus conducted a retrospective study in 21 consecutive patients suffering from drug-resistant seizures studied by SEEG recordings. Ictal FA were quantified using the Epileptogenicity Maps (EM) method that we recently developed and which generates, by adopting a neuroimaging approach, statistical parametric maps of FA ranging from 60 to 100 Hz (FA60−100). Ictal FA were analyzed blindly using VA and EM, and the prognostic significance of removing areas exhibiting FA60−100 at seizure onset was evaluated. A significant ictal FA60−100 activation was found in all patients, and in 92.6% of all the 68 seizures recorded, whatever the epilepsy type. The overlap ratio (OR) between VA and EM was significantly better for defining the regions spared at seizure onset than those from which seizure arose (p < 0.001), especially in temporal or temporal “plus” epilepsies. EM and VA were much more discordant to define the EZ, with a mean number of electrode contacts involved at seizure onset significantly higher with EM than with VA (p = <0.0001). Seizure outcome correlated with the resection ratio for FA60−100, which was significantly higher in seizure-free (Engel's class Ia) than in non seizure-free patients (class Ic-IV) (p = 0.048). The quantification of FA at seizure onset can bring information additional to clinical expertise that might contribute to define accurately the cortical region to be resected.
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Affiliation(s)
- Anne-Sophie Job
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Olivier David
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France.,INS, Inserm, U1106, Marseille, France
| | - Lorella Minotti
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Fabrice Bartolomei
- INS, Inserm, U1106, Marseille, France.,Neurophysiology Departement, La Timone Hospital, Marseille, France
| | - Stephan Chabardès
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
| | - Philippe Kahane
- Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Université Grenoble Alpes, Grenoble, France
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6
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Müller M, Caporro M, Gast H, Pollo C, Wiest R, Schindler K, Rummel C. Linear and nonlinear interrelations show fundamentally distinct network structure in preictal intracranial EEG of epilepsy patients. Hum Brain Mapp 2019; 41:467-483. [PMID: 31625670 PMCID: PMC7268049 DOI: 10.1002/hbm.24816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/24/2022] Open
Abstract
Resection of the seizure generating tissue can be highly beneficial in patients with drug-resistant epilepsy. However, only about half of all patients undergoing surgery get permanently and completely seizure free. Investigating the dependences between intracranial EEG signals adds a multivariate perspective largely unavailable to visual EEG analysis, which is the current clinical practice. We examined linear and nonlinear interrelations between intracranial EEG signals regarding their spatial distribution and network characteristics. The analyzed signals were recorded immediately before clinical seizure onset in epilepsy patients who received a standardized electrode implantation targeting the mesiotemporal structures. The linear interrelation networks were predominantly locally connected and highly reproducible between patients. In contrast, the nonlinear networks had a clearly centralized structure, which was specific for the individual pathology. The nonlinear interrelations were overrepresented in the focal hemisphere and in patients with no or only rare seizures after surgery specifically in the resected tissue. Connections to the outside were predominantly nonlinear. In all patients without worthwhile improvement after resective treatment, tissue producing strong nonlinear interrelations was left untouched by surgery. Our findings indicate that linear and nonlinear interrelations play fundamentally different roles in preictal intracranial EEG. Moreover, they suggest nonlinear signal interrelations to be a marker of epileptogenic tissue and not a characteristic of the mesiotemporal structures. Our results corroborate the network-based nature of epilepsy and suggest the application of network analysis to support the planning of resective epilepsy surgery.
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Affiliation(s)
- Michael Müller
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland.,Department of Neurology, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland
| | - Matteo Caporro
- Department of Neurology, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland
| | - Heidemarie Gast
- Department of Neurology, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland
| | - Claudio Pollo
- Department of Neurosurgery, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland
| | - Roland Wiest
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Kaspar Schindler
- Department of Neurology, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland
| | - Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
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Ren S, Gliske SV, Brang D, Stacey WC. Redaction of false high frequency oscillations due to muscle artifact improves specificity to epileptic tissue. Clin Neurophysiol 2019; 130:976-985. [PMID: 31003116 DOI: 10.1016/j.clinph.2019.03.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/04/2019] [Accepted: 03/16/2019] [Indexed: 11/17/2022]
Abstract
OBJECTIVE High Frequency Oscillations (HFOs) are a promising biomarker of epilepsy. HFOs are typically acquired on intracranial electrodes, but contamination from muscle artifacts is still problematic in HFO analysis. This paper evaluates the effect of myogenic artifacts on intracranial HFO detection and how to remove them. METHODS Intracranial EEG was recorded in 31 patients. HFOs were detected for the entire recording using an automated algorithm. When available, simultaneous scalp EEG was used to identify periods of muscle artifact. Those markings were used to train an automated scalp EMG detector and an intracranial EMG detector. Specificity to epileptic tissue was evaluated by comparison with seizure onset zone and resected volume in patients with good outcome. RESULTS EMG artifacts are frequent and produce large numbers of false HFOs, especially in the anterior temporal lobe. The scalp and intracranial EMG detectors both had high accuracy. Removing false HFOs improved specificity to epileptic tissue. CONCLUSIONS Evaluation of HFOs requires accounting for the effect of muscle artifact. We present two tools that effectively mitigate the effect of muscle artifact on HFOs. SIGNIFICANCE Removing muscle artifacts improves the specificity of HFOs to epileptic tissue. Future HFO work should account for this effect, especially when using automated algorithms or when scalp electrodes are not present.
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Affiliation(s)
- Sijin Ren
- Department of Neurology, University of Michigan, USA.
| | - Stephen V Gliske
- Department of Neurology, University of Michigan, USA; Department of Biomedical Engineering, Biointerfaces Institute, University of Michigan, USA.
| | - David Brang
- Department of Psychology, University of Michigan, USA.
| | - William C Stacey
- Department of Neurology, University of Michigan, USA; Department of Biomedical Engineering, Biointerfaces Institute, University of Michigan, USA.
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8
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Abstract
Removing High-Frequency Oscillations: A Prospective Multicenter Study on Seizure Outcome Jacobs J, Wu JY, Perucca P, et al. Neurology. 2018;91(11):e1040-e1052. doi:10.1212/WNL.0000000000006158 Objective: To evaluate the use of interictal high-frequency oscillations (HFOs) in epilepsy surgery for prediction of postsurgical seizure outcome in a prospective multicenter trial. Methods: We hypothesized that a seizure-free outcome could be expected in patients in whom the surgical planning included the majority of HFO-generating brain tissue, while a poor seizure outcome could be expected in patients in whom only a few such areas were planned to be resected. Fifty-two patients were included from 3 tertiary epilepsy centers during a 1-year period. Ripples (80-250 Hz) and fast ripples (250-500 Hz) were automatically detected during slow-wave sleep with chronic intracranial EEG in 2 centers and acute intraoperative electrocorticography in 1 patient. Results: There was a correlation between the removal of HFO-generating regions and seizure-free outcome at the group level for all patients. No correlation was found, however, for the center-specific analysis, and an individual prognostication of seizure outcome was true in only 36 (67%) patients. Moreover, some patients became seizure-free without removal of the majority of HFO-generating tissue. The investigation of influencing factors, including comparisons of visual and automatic analysis, using a threshold analysis for areas with high HFO activity, and excluding contacts bordering the resection, did not result in improved prognostication. Conclusions: On an individual patient level, a prediction of outcome was not possible in all patients. This may be due to the analysis techniques used. Alternatively, HFOs may be less specific for epileptic tissue than earlier studies have indicated.
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9
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Thomschewski A, Hincapié AS, Frauscher B. Localization of the Epileptogenic Zone Using High Frequency Oscillations. Front Neurol 2019; 10:94. [PMID: 30804887 PMCID: PMC6378911 DOI: 10.3389/fneur.2019.00094] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/23/2019] [Indexed: 01/22/2023] Open
Abstract
For patients with drug-resistant focal epilepsy, surgery is the therapy of choice in order to achieve seizure freedom. Epilepsy surgery foremost requires the identification of the epileptogenic zone (EZ), defined as the brain area indispensable for seizure generation. The current gold standard for identification of the EZ is the seizure-onset zone (SOZ). The fact, however that surgical outcomes are unfavorable in 40-50% of well-selected patients, suggests that the SOZ is a suboptimal biomarker of the EZ, and that new biomarkers resulting in better postsurgical outcomes are needed. Research of recent years suggested that high-frequency oscillations (HFOs) are a promising biomarker of the EZ, with a potential to improve surgical success in patients with drug-resistant epilepsy without the need to record seizures. Nonetheless, in order to establish HFOs as a clinical biomarker, the following issues need to be addressed. First, evidence on HFOs as a clinically relevant biomarker stems predominantly from retrospective assessments with visual marking, leading to problems of reproducibility and reliability. Prospective assessments of the use of HFOs for surgery planning using automatic detection of HFOs are needed in order to determine their clinical value. Second, disentangling physiologic from pathologic HFOs is still an unsolved issue. Considering the appearance and the topographic location of presumed physiologic HFOs could be immanent for the interpretation of HFO findings in a clinical context. Third, recording HFOs non-invasively via scalp electroencephalography (EEG) and magnetoencephalography (MEG) is highly desirable, as it would provide us with the possibility to translate the use of HFOs to the scalp in a large number of patients. This article reviews the literature regarding these three issues. The first part of the article focuses on the clinical value of invasively recorded HFOs in localizing the EZ, the detection of HFOs, as well as their separation from physiologic HFOs. The second part of the article focuses on the current state of the literature regarding non-invasively recorded HFOs with emphasis on findings and technical considerations regarding their localization.
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Affiliation(s)
- Aljoscha Thomschewski
- Department of Neurology, Christian Doppler Medical Center, Paracelsus Medical University, Salzburg, Austria,Department of Psychology, Paris-Lodron University of Salzburg, Salzburg, Austria
| | - Ana-Sofía Hincapié
- Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Birgit Frauscher
- Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada,*Correspondence: Birgit Frauscher
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10
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Alter AS, Dhamija R, McDonough TL, Shen S, McBrian DK, Mandel AM, McKhann GM, Feldstein NA, Akman CI. Ictal onset patterns of subdural intracranial electroencephalogram in children: How helpful for predicting epilepsy surgery outcome? Epilepsy Res 2018; 149:44-52. [PMID: 30476812 DOI: 10.1016/j.eplepsyres.2018.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/26/2018] [Accepted: 10/21/2018] [Indexed: 11/28/2022]
Abstract
AIMS We aimed to classify ictal onset patterns (IOPs) in pediatric patients undergoing intracranial electroencephalography (IEEG) to guide surgery for refractory epilepsy. We aimed to determine if morphology of IOPs can predict surgical outcome. MATERIALS AND METHODS We performed a retrospective review of pediatric patients who underwent epilepsy surgery guided by subdural IEEG from 2007 to 2016. IEEG seizures were reviewed by a blinded epileptologist. Data was collected on outcomes. RESULTS Twenty-three patients with 784 seizures were included. Age at seizure onset was 0.2-11 (mean 4.3, standard deviation 3.2) years. Age at time of IEEG was 4-20 (mean 13.5, standard deviation 4.4) years. Five distinct IOPs were seen at seizure onset: A) Low voltage fast activity (LVFA) with spread to adjacent electrodes (n = 7 patients, 30%), B) Burst of LVFA followed by electrodecrement (n = 12 patients, 52%), C) Burst of rhythmic spike waves (RSW) followed by electrodecrement (n = 9 patients, 39%), D) RSW followed by LVFA (n = 7 patients, 30%), E) Rhythmic spikes alone (n = 10 patients, 43%). Twelve patients (52%) had the same IOP type with all seizures. When the area of the IOP was resected, 14 patients (61%) had Engel I outcomes. Patients who had LVFA seen within their predominant IOP type were more likely to have good surgical outcomes (odds ratio 7.50, 95% confidence interval 1.02-55.0, p = 0.05). Patients who had only one IOP type were more likely to have good outcomes than patients who had multiple IOP types (odds ratio 12.6, 95% confidence interval 1.19-134, p = 0.04). Patients who had LVFA in their predominant IOP type were older than patients who did not have LVFA (mean age 15.0 vs. 9.9 years, p = 0.02). CONCLUSIONS LVFA at ictal onset and all seizures having the same IOP morphology are associated with increased likelihood of surgical success in children, but LVFA is less common in children who are younger at the time of IEEG.
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Affiliation(s)
- Aliza S Alter
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Ravi Dhamija
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Tiffani L McDonough
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Stephie Shen
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Danielle K McBrian
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Arthur M Mandel
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, 710 West 168th Street, New York, New York, USA.
| | - Neil A Feldstein
- Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, 710 West 168th Street, New York, New York, USA.
| | - Cigdem I Akman
- Department of Neurology, Division of Child Neurology, New York-Presbyterian Hospital/ Columbia University College of Physicians and Surgeons, 180 Fort Washington Avenue, New York, New York, USA.
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11
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Sumsky SL, Santaniello S. Decision Support System for Seizure Onset Zone Localization Based on Channel Ranking and High-Frequency EEG Activity. IEEE J Biomed Health Inform 2018; 23:1535-1545. [PMID: 30176615 DOI: 10.1109/jbhi.2018.2867875] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Interictal high-frequency oscillations (HFO) are a promising biomarker that can help define the seizure onset zone (SOZ) and predict the surgical outcome after the epilepsy surgery. The utility of HFO in planning the surgery, though, is unclear. Reasons include the variability of the HFO across patients and brain regions and the influence of the sleep-wake cycle, which causes large fluctuations in the ratio between the HFO observed in SOZ and non-SOZ regions. To cope with these limitations, a rank-based solution is proposed to identify the SOZ by using the HFO in multichannel intracranial EEG. A time-varying index of the epileptic susceptibility of the different brain areas is derived from the HFO rate and a support vector machine is applied on this index to identify the SOZ. The solution is trained and tested on separate groups of patients to avoid the use of patient-specific information and provides optimal SOZ prediction using as little as 30 min of recordings per channel (window). Tested on 14 patients with various combinations of seizure type, epilepsy etiology, and SOZ arrangement (172.7 ± 90.1 h/channel per patient and 75.6 ± 23.5 channels/patient, mean ± S.D.), our solution identified the SOZ with 0.92 ± 0.03 accuracy and 0.91 ± 0.03 area under the ROC curve (mean ± S.D.) across patients. For each patient, the window onset time was varied over 72 continuous hours and the prediction of the SOZ remained insensitive to the onset time, thus showing potential for surgery planning.
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Jacobs J, Wu JY, Perucca P, Zelmann R, Mader M, Dubeau F, Mathern GW, Schulze-Bonhage A, Gotman J. Removing high-frequency oscillations: A prospective multicenter study on seizure outcome. Neurology 2018; 91:e1040-e1052. [PMID: 30120133 DOI: 10.1212/wnl.0000000000006158] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 06/12/2018] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate the use of interictal high-frequency oscillations (HFOs) in epilepsy surgery for prediction of postsurgical seizure outcome in a prospective multicenter trial. METHODS We hypothesized that a seizure-free outcome could be expected in patients in whom the surgical planning included the majority of HFO-generating brain tissue while a poor seizure outcome could be expected in patients in whom only a few such areas were planned to be resected. Fifty-two patients were included from 3 tertiary epilepsy centers during a 1-year period. Ripples (80-250 Hz) and fast ripples (250-500 Hz) were automatically detected during slow-wave sleep with chronic intracranial EEG in 2 centers and acute intraoperative electrocorticography in 1 patient. RESULTS There was a correlation between the removal of HFO-generating regions and seizure-free outcome at the group level for all patients. No correlation was found, however, for the center-specific analysis, and an individual prognostication of seizure outcome was true in only 36 patients (67%). Moreover, some patients became seizure-free without removal of the majority of HFO-generating tissue. The investigation of influencing factors, including comparisons of visual and automatic analysis, using a threshold analysis for areas with high HFO activity, and excluding contacts bordering the resection, did not result in improved prognostication. CONCLUSIONS On an individual patient level, a prediction of outcome was not possible in all patients. This may be due to the analysis techniques used. Alternatively, HFOs may be less specific for epileptic tissue than earlier studies have indicated.
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Affiliation(s)
- Julia Jacobs
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada.
| | - Joyce Y Wu
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Piero Perucca
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Rina Zelmann
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Malenka Mader
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Francois Dubeau
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Gary W Mathern
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Andreas Schulze-Bonhage
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
| | - Jean Gotman
- From the Department of Neuropediatrics and Muscular Diseases (J.J., M.M.) and Epilepsy Center (J.J., A.S.-B.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Division of Pediatric Neurology (J.Y.W., G.W.M.), David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA; and Montreal Neurological Institute (P.P., R.Z., F.D., J.G.), McGill University, Quebec, Canada
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13
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Abstract
BACKGROUND Epilepsy is a serious brain disorder characterized by recurrent unprovoked seizures. Approximately two-thirds of seizures can be controlled with antiepileptic medications (Kwan 2000). For some of the others, surgery can completely eliminate or significantly reduce the occurrence of disabling seizures. Localization of epileptogenic areas for resective surgery is far from perfect, and new tools are being investigated to more accurately localize the epileptogenic zone (the zone of the brain where the seizures begin) and improve the likelihood of freedom from postsurgical seizures. Recordings of pathological high-frequency oscillations (HFOs) may be one such tool. OBJECTIVES To assess the ability of HFOs to improve the outcomes of epilepsy surgery by helping to identify more accurately the epileptogenic areas of the brain. SEARCH METHODS For the latest update, we searched the Cochrane Epilepsy Group Specialized Register (25 July 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 25 July 2016), MEDLINE (Ovid, 1946 to 25 July 2016), CINAHL Plus (EBSCOhost, 25 July 2016), Web of Science (Thomson Reuters, 25 July 2016), ClinicalTrials.gov (25 July 2016), and the World Health Organization International Clinical Trials Registry Platform ICTRP (25 July 2016). SELECTION CRITERIA We included studies that provided information on the outcomes of epilepsy surgery for at least six months and which used high-frequency oscillations in making decisions about epilepsy surgery. DATA COLLECTION AND ANALYSIS The primary outcome of the review was the Engel Class Outcome System (class I = no disabling seizures, II = rare disabling seizures, III = worthwhile improvement, IV = no worthwhile improvement). Secondary outcomes were responder rate, International League Against Epilepsy (ILAE) epilepsy surgery outcome, frequency of adverse events from any source and quality of life outcomes. We intended to analyse outcomes via an aggregated data fixed-effect model meta-analysis. MAIN RESULTS Two studies representing 11 participants met the inclusion criteria. Both studies were small non-randomised trials, with no control group and no blinding. The quality of evidence for all outcomes was very low. The combination of these two studies resulted in 11 participants who prospectively used ictal HFOs for epilepsy surgery decision making. Results of the postsurgical seizure freedom Engel class I to IV outcome were determined over a period of 12 to 38 months (average 23.4 months) and indicated that six participants had an Engel class I outcome (seizure freedom), two had class II (rare disabling seizures), three had class III (worthwhile improvement). No adverse effects were reported. Neither study compared surgical results guided by HFOs versus surgical results guided without HFOs. AUTHORS' CONCLUSIONS No reliable conclusions can be drawn regarding the efficacy of using HFOs in epilepsy surgery decision making at present.
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Affiliation(s)
- David Gloss
- Charleston Area Medical CenterCAMC Neurology415 Morris StSuite 300CharlestonUSAWV 25301
| | - Sarah J Nevitt
- University of LiverpoolDepartment of BiostatisticsBlock F, Waterhouse Building1‐5 Brownlow HillLiverpoolUKL69 3GL
| | - Richard Staba
- University of CaliforniaDepartment of NeurologyReed Neurologic Research Center710 Westwood Plaza, Suite 1‐250Los AngelesCaliforniaUSA90095
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14
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Frauscher B, Bartolomei F, Kobayashi K, Cimbalnik J, van 't Klooster MA, Rampp S, Otsubo H, Höller Y, Wu JY, Asano E, Engel J, Kahane P, Jacobs J, Gotman J. High-frequency oscillations: The state of clinical research. Epilepsia 2017; 58:1316-1329. [PMID: 28666056 DOI: 10.1111/epi.13829] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2017] [Indexed: 01/03/2023]
Abstract
Modern electroencephalographic (EEG) technology contributed to the appreciation that the EEG signal outside the classical Berger frequency band contains important information. In epilepsy, research of the past decade focused particularly on interictal high-frequency oscillations (HFOs) > 80 Hz. The first large application of HFOs was in the context of epilepsy surgery. This is now followed by other applications such as assessment of epilepsy severity and monitoring of antiepileptic therapy. This article reviews the evidence on the clinical use of HFOs in epilepsy with an emphasis on the latest developments. It highlights the growing literature on the association between HFOs and postsurgical seizure outcome. A recent meta-analysis confirmed a higher resection ratio for HFOs in seizure-free versus non-seizure-free patients. Residual HFOs in the postoperative electrocorticogram were shown to predict epilepsy surgery outcome better than preoperative HFO rates. The review further discusses the different attempts to separate physiological from epileptic HFOs, as this might increase the specificity of HFOs. As an example, analysis of sleep microstructure demonstrated a different coupling between HFOs inside and outside the epileptogenic zone. Moreover, there is increasing evidence that HFOs are useful to measure disease activity and assess treatment response using noninvasive EEG and magnetoencephalography. This approach is particularly promising in children, because they show high scalp HFO rates. HFO rates in West syndrome decrease after adrenocorticotropic hormone treatment. Presence of HFOs at the time of rolandic spikes correlates with seizure frequency. The time-consuming visual assessment of HFOs, which prevented their clinical application in the past, is now overcome by validated computer-assisted algorithms. HFO research has considerably advanced over the past decade, and use of noninvasive methods will make HFOs accessible to large numbers of patients. Prospective multicenter trials are awaited to gather information over long recording periods in large patient samples.
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Affiliation(s)
- Birgit Frauscher
- Department of Medicine and Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Fabrice Bartolomei
- National Institute of Health and Medical Research, Institute of Neurosciences of Systems, Aix Marseille University, Marseille, France
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Hospital, Kita-ku, Okayama, Japan
| | - Jan Cimbalnik
- International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
| | - Maryse A van 't Klooster
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stefan Rampp
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - Hiroshi Otsubo
- Division of Neurology, Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yvonne Höller
- Department of Neurology, Christian Doppler Medical Center and Center for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Joyce Y Wu
- Division of Pediatric Neurology, Mattel Children's Hospital at UCLA, Los Angeles, California, U.S.A
| | - Eishi Asano
- Departments of Pediatrics and Neurology, Detroit Medical Center, Children's Hospital of Michigan, Wayne State University, Detroit, Michigan, U.S.A
| | - Jerome Engel
- Departments of Neurology, Neurobiology, and Psychiatry, Brain Research Institute, University of California, Los Angeles, Los Angeles, California, U.S.A
| | - Philippe Kahane
- Department of Neurology, Grenoble-Alpes University Hospital and Grenoble-Alpes University, Grenoble, France
| | - Julia Jacobs
- Department of Neuropediatrics and Muscular Diseases, University Medical Center Freiburg, Freiburg, Germany
| | - Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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15
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Navarrete M, Pyrzowski J, Corlier J, Valderrama M, Le Van Quyen M. Automated detection of high-frequency oscillations in electrophysiological signals: Methodological advances. ACTA ACUST UNITED AC 2017; 110:316-326. [PMID: 28235667 DOI: 10.1016/j.jphysparis.2017.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 01/31/2017] [Accepted: 02/19/2017] [Indexed: 01/17/2023]
Abstract
In recent years, new recording technologies have advanced such that oscillations of neuronal networks can be identified from simultaneous, multisite recordings at high temporal and spatial resolutions. However, because of the deluge of multichannel data generated by these experiments, achieving the full potential of parallel neuronal recordings also depends on the development of new mathematical methods capable of extracting meaningful information related to time, frequency and space. In this review, we aim to bridge this gap by focusing on the new analysis tools developed for the automated detection of high-frequency oscillations (HFOs, >40Hz) in local field potentials. For this, we provide a revision of different aspects associated with physiological and pathological HFOs as well as the several stages involved in their automatic detection including preprocessing, selection, rejection and analysis through time-frequency processes. Beyond basic research, the automatic detection of HFOs would greatly assist diagnosis of epilepsy disorders based on the recognition of these typical pathological patterns in the electroencephalogram (EEG). Also, we emphasize how these HFO detection methods can be applied and the properties that might be inferred from neuronal signals, indicating potential future directions.
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Affiliation(s)
- Miguel Navarrete
- Department of Biomedical Engineering, University of Los Andes, Bogotá D.C., Colombia
| | - Jan Pyrzowski
- Institut du Cerveau et de la Moelle Epinière, UMR S 1127, CNRS UMR 7225, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Juliana Corlier
- Institut du Cerveau et de la Moelle Epinière, UMR S 1127, CNRS UMR 7225, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Mario Valderrama
- Department of Biomedical Engineering, University of Los Andes, Bogotá D.C., Colombia
| | - Michel Le Van Quyen
- Institut du Cerveau et de la Moelle Epinière, UMR S 1127, CNRS UMR 7225, Hôpital de la Pitié-Salpêtrière, Paris, France.
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16
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Asano E. High-frequency oscillations are under your control. Don't chase all of them. Clin Neurophysiol 2017; 128:841-842. [PMID: 28283356 DOI: 10.1016/j.clinph.2017.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 10/20/2022]
Affiliation(s)
- Eishi Asano
- Departments of Pediatrics and Neurology, Children's Hospital of Michigan, Wayne State University, Detroit Medical Center, Detroit, MI 48201, USA.
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17
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Tamilia E, Madsen JR, Grant PE, Pearl PL, Papadelis C. Current and Emerging Potential of Magnetoencephalography in the Detection and Localization of High-Frequency Oscillations in Epilepsy. Front Neurol 2017; 8:14. [PMID: 28194133 PMCID: PMC5276819 DOI: 10.3389/fneur.2017.00014] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/11/2017] [Indexed: 01/19/2023] Open
Abstract
Up to one-third of patients with epilepsy are medically intractable and need resective surgery. To be successful, epilepsy surgery requires a comprehensive preoperative evaluation to define the epileptogenic zone (EZ), the brain area that should be resected to achieve seizure freedom. Due to lack of tools and methods that measure the EZ directly, this area is defined indirectly based on concordant data from a multitude of presurgical non-invasive tests and intracranial recordings. However, the results of these tests are often insufficiently concordant or inconclusive. Thus, the presurgical evaluation of surgical candidates is frequently challenging or unsuccessful. To improve the efficacy of the surgical treatment, there is an overriding need for reliable biomarkers that can delineate the EZ. High-frequency oscillations (HFOs) have emerged over the last decade as new potential biomarkers for the delineation of the EZ. Multiple studies have shown that HFOs are spatially associated with the EZ. Despite the encouraging findings, there are still significant challenges for the translation of HFOs as epileptogenic biomarkers to the clinical practice. One of the major barriers is the difficulty to detect and localize them with non-invasive techniques, such as magnetoencephalography (MEG) or scalp electroencephalography (EEG). Although most literature has studied HFOs using invasive recordings, recent studies have reported the detection and localization of HFOs using MEG or scalp EEG. MEG seems to be particularly advantageous compared to scalp EEG due to its inherent advantages of being less affected by skull conductivity and less susceptible to contamination from muscular activity. The detection and localization of HFOs with MEG would largely expand the clinical utility of these new promising biomarkers to an earlier stage in the diagnostic process and to a wider range of patients with epilepsy. Here, we conduct a thorough critical review of the recent MEG literature that investigates HFOs in patients with epilepsy, summarizing the different methodological approaches and the main findings. Our goal is to highlight the emerging potential of MEG in the non-invasive detection and localization of HFOs for the presurgical evaluation of patients with medically refractory epilepsy (MRE).
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Affiliation(s)
- Eleonora Tamilia
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Joseph R. Madsen
- Division of Epilepsy Surgery, Department of Neurosurgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Patricia Ellen Grant
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Phillip L. Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Christos Papadelis
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
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18
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Jin P, Wu D, Li X, Ren L, Wang Y. Towards precision medicine in epilepsy surgery. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:24. [PMID: 26889477 DOI: 10.3978/j.issn.2305-5839.2015.12.65] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Up to a third of all patients with epilepsy are refractory to medical therapy even in the context of the introduction of new antiepileptic drugs (AEDs) with considerable advantages in safety and tolerability over the last two decades. It has been widely accepted that epilepsy surgery is a highly effective therapeutic option in a selected subset of patients with refractory focal seizure. There is no doubt that accurate localization of the epileptogenic zone (EZ) is crucial to the success of resection surgery for intractable epilepsy. The pre-surgical evaluation requires a multimodality approach wherein each modality provides unique and complimentary information. Accurate localization of EZ still remains challenging, especially in patients with normal features on MRI. Whereas substantial progress has been made in the methods of pre-surgical assessment in recent years, which widened the applicability of surgical treatment for children and adults with refractory seizure. Advances in neuroimaging including voxel-based morphometric MRI analysis, multimodality techniques and computer-aided subtraction ictal SPECT co-registered to MRI have improved our ability to identify subtle structural and metabolic lesions causing focal seizure. Considerable observations from animal model with epilepsy and pre-surgical patients have consistently found a strong correlation between high frequency oscillations (HFOs) and epileptogenic brain tissue that suggest HFOs could be a potential biomarker of EZ. Since SEEG emphasizes the importance to study the spatiotemporal dynamics of seizure discharges, accounting for the dynamic, multidirectional spatiotemporal organization of the ictal discharges, it has greatly deep our understanding of the anatomo-electro-clinical profile of seizure. In this review, we focus on some state-of-the-art pre-surgical investigations that contribute to the precision medicine. Furthermore, advances also provide opportunity to achieve the minimal side effects and maximal benefit individually, which meets the need for the current concept of precision medicine in epilepsy surgery.
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Affiliation(s)
- Pingping Jin
- 1 Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China ; 2 Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China ; 3 Department of Neurology, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Dongyan Wu
- 1 Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China ; 2 Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China ; 3 Department of Neurology, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xiaoxuan Li
- 1 Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China ; 2 Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China ; 3 Department of Neurology, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Liankun Ren
- 1 Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China ; 2 Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China ; 3 Department of Neurology, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Yuping Wang
- 1 Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China ; 2 Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China ; 3 Department of Neurology, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
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Jacobs J, Vogt C, LeVan P, Zelmann R, Gotman J, Kobayashi K. The identification of distinct high-frequency oscillations during spikes delineates the seizure onset zone better than high-frequency spectral power changes. Clin Neurophysiol 2016; 127:129-142. [DOI: 10.1016/j.clinph.2015.04.053] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 03/12/2015] [Accepted: 04/04/2015] [Indexed: 10/23/2022]
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20
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Höller Y, Kutil R, Klaffenböck L, Thomschewski A, Höller PM, Bathke AC, Jacobs J, Taylor AC, Nardone R, Trinka E. High-frequency oscillations in epilepsy and surgical outcome. A meta-analysis. Front Hum Neurosci 2015; 9:574. [PMID: 26539097 PMCID: PMC4611152 DOI: 10.3389/fnhum.2015.00574] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/02/2015] [Indexed: 01/14/2023] Open
Abstract
High frequency oscillations (HFOs) are estimated as a potential marker for epileptogenicity. Current research strives for valid evidence that these HFOs could aid the delineation of the to-be resected area in patients with refractory epilepsy and improve surgical outcomes. In the present meta-analysis, we evaluated the relation between resection of regions from which HFOs can be detected and outcome after epilepsy surgery. We conducted a systematic review of all studies that related the resection of HFO-generating areas to postsurgical outcome. We related the outcome (seizure freedom) to resection ratio, that is, the ratio between the number of channels on which HFOs were detected and, among these, the number of channels that were inside the resected area. We compared the resection ratio between seizure free and not seizure free patients. In total, 11 studies were included. In 10 studies, ripples (80-200 Hz) were analyzed, and in 7 studies, fast ripples (>200 Hz) were studied. We found comparable differences (dif) and largely overlapping confidence intervals (CI) in resection ratios between outcome groups for ripples (dif = 0.18; CI: 0.10-0.27) and fast ripples (dif = 0.17; CI: 0.01-0.33). Subgroup analysis showed that automated detection (dif = 0.22; CI: 0.03-0.41) was comparable to visual detection (dif = 0.17; CI: 0.08-0.27). Considering frequency of HFOs (dif = 0.24; CI: 0.09-0.38) was related more strongly to outcome than considering each electrode that was showing HFOs (dif = 0.15; CI = 0.03-0.27). The effect sizes found in the meta-analysis are small but significant. Automated detection and application of a detection threshold in order to detect channels with a frequent occurrence of HFOs is important to yield a marker that could be useful in presurgical evaluation. In order to compare studies with different methodological approaches, detailed and standardized reporting is warranted.
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Affiliation(s)
- Yvonne Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Raoul Kutil
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Lukas Klaffenböck
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Aljoscha Thomschewski
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Peter M Höller
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Arne C Bathke
- Department of Mathematics, Paris Lodron University Salzburg, Austria
| | - Julia Jacobs
- Department of Neuropediatrics and Muscular Diseases and Epilepsy Center, University Medical Center Freiburg, Germany
| | - Alexandra C Taylor
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
| | - Raffaele Nardone
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria ; Department of Neurology, Franz Tappeiner Hospital Merano, Italy
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, Paracelsus Medical University Salzburg, Austria
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Leiken K, Xiang J, Zhang F, Shi J, Tang L, Liu H, Wang X. Magnetoencephalography detection of high-frequency oscillations in the developing brain. Front Hum Neurosci 2014; 8:969. [PMID: 25566015 PMCID: PMC4264504 DOI: 10.3389/fnhum.2014.00969] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/13/2014] [Indexed: 11/13/2022] Open
Abstract
Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG) methods. Twenty healthy children were studied with a high-sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (>1000 Hz) in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI) revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.
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Affiliation(s)
- Kimberly Leiken
- Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA
| | - Jing Xiang
- Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA
| | - Fawen Zhang
- Department of Communication Sciences and Disorders, University of Cincinnati , Cincinnati, OH , USA
| | - Jingping Shi
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China
| | - Lu Tang
- Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China
| | - Hongxing Liu
- Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China
| | - Xiaoshan Wang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China
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22
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Abstract
In patients being evaluated for epilepsy and in animal models of epilepsy, electrophysiological recordings are carried to capture seizures to determine the existence of epilepsy. Electroencephalography recordings from the scalp, or sometimes directly from the brain, are also used to locate brain areas where seizure begins, and in surgical treatment help plan the area for resection. As seizures are unpredictable and can occur infrequently, ictal recordings are not ideal in terms of time, cost, or risk when, for example, determining the efficacy of existing or new anti-seizure drugs, evaluating potential anti-epileptogenic interventions, or for prolonged intracerebral electrode studies. Thus, there is a need to identify and validate other electrophysiological biomarkers of epilepsy that could be used to diagnose, treat, cure, and prevent epilepsy. Electroencephalography recordings in the epileptic brain contain other interictal electrophysiological disturbances that can occur more frequently than seizures, such as interictal spikes (IIS) and sharp waves, and from invasive studies using wide bandwidth recording and small diameter electrodes, the discovery of pathological high-frequency oscillations (HFOs) and microseizures. Of IIS, HFOs, and microseizures, a significant amount of recent research has focused on HFOs in the pathophysiology of epilepsy. Results from studies in animals with epilepsy and presurgical patients have consistently found a strong association between HFOs and epileptogenic brain tissue that suggest HFOs could be a potential biomarker of epileptogenicity and epileptogenesis. Here, we discuss several aspects of HFOs, as well as IIS and microseizures, and the evidence that supports their role as biomarkers of epilepsy.
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Affiliation(s)
- Richard J Staba
- David Geffen School of Medicine at UCLA, Department of Neurology, Room 2-155, 710 Westwood Plaza, Los Angeles, CA, 90095, USA,
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