Article
Clinical Neurology
Robert J. Quon, Edward J. Camp, Stephen Meisenhelter, Yinchen Song, Sarah A. Steimel, Markus E. Testorf, Angeline S. Andrew, Robert E. Gross, Bradley C. Lega, Michael R. Sperling, Michael J. Kahana, Barbara C. Jobst
Summary: The study investigated the impact of interictal epileptiform discharges (IEDs) on memory performance, finding that increased IED rate, white matter propagation, and localization in the left middle temporal region were associated with poorer memory performance. Specifically for lateral temporal IEDs, there was a significant interaction between IED white matter classification and amplitude, where higher amplitude and white matter propagation were linked to reduced memory performance. Additionally, changes in alpha power after an IED were positively correlated with memory performance.
Article
Clinical Neurology
Robert J. Quon, Stephen Meisenhelter, Richard H. Adamovich-Zeitlin, Yinchen Song, Sarah A. Steimel, Edward J. Camp, Markus E. Testorf, Todd A. MacKenzie, Robert E. Gross, Bradley C. Lega, Michael R. Sperling, Michael J. Kahana, Barbara C. Jobst
Summary: This study evaluates the influence of subject-specific factors on intracranial interictal epileptiform discharge (IED) rates in patients with refractory epilepsy. Antiseizure medication status, time of testing, and seizure onset zone location were found to have the highest impact on IED rates. Factors like SOZ location and ASM status are crucial when analyzing IEDs for clinical or research purposes.
Article
Engineering, Biomedical
Elif Koksal-Ersoz, Remo Lazazzera, Maxime Yochum, Isabelle Merlet, Julia Makhalova, Borja Mercadal, Roser Sanchez-Todo, Giulio Ruffini, Fabrice Bartolomei, Pascal Benquet, Fabrice Wendling
Summary: This study investigates the generation mechanisms of IEDs in partial epilepsies through signal analysis and mathematical modeling. The researchers identify two classes of SWs and determine their distribution in epileptic and non-epileptic zones. The modeling results suggest a correlation between the morphology of IEDs and the degree of inhibition preservation.
JOURNAL OF NEURAL ENGINEERING
(2022)
Article
Clinical Neurology
Robert J. Quon, Stephen Meisenhelter, Edward J. Camp, Markus E. Testorf, Yinchen Song, Qingyuan Song, George W. Culler, Payam Moein, Barbara C. Jobst
Summary: The study utilized an automated method combining template-matching algorithm and CNN to successfully detect intracranial IEDs with high F1 score and AUC. On the external test set, it was able to identify 100% of high-amplitude IED complexes, 96.23% of high amplitude isolated IEDs, and 66.15% of IEDs with atypical morphology.
CLINICAL NEUROPHYSIOLOGY
(2022)
Article
Clinical Neurology
Radek Janca, Petr Jezdik, Matyas Ebel, Adam Kalina, Martin Kudr, Alena Jahodova, David Krysl, Katerina Mackova, Barbora Straka, Petr Marusic, Pavel Krsek
Summary: This study demonstrates that electrophysiological patterns can accurately differentiate FCD types and help predict presurgical MRI findings, providing more precise surgical plans for patients.
CLINICAL NEUROPHYSIOLOGY
(2023)
Article
Biology
Elliot H. Smith, Jyun-You Liou, Edward M. Merricks, Tyler Davis, Kyle Thomson, Bradley Greger, Paul House, Ronald G. Emerson, Robert Goodman, Guy M. McKhann, Sameer Sheth, Catherine Schevon, John D. Rolston
Summary: This study investigates the relationship between interictal epileptiform discharges (IEDs) and seizures. The findings demonstrate a spatiotemporal similarity between IEDs and ictal discharges, suggesting that the propagation of IEDs can provide useful information for localizing the seizure focus.
Article
Clinical Neurology
Peter N. Taylor, Christoforos A. Papasavvas, Thomas W. Owen, Gabrielle M. Schroeder, Frances E. Hutchings, Fahmida A. Chowdhury, Beate Diehl, John S. Duncan, Andrew W. McEvoy, Anna Miserocchi, Jane de Tisi, Sjoerd B. Vos, Matthew C. Walker, Yujiang Wang
Summary: This study investigates the detection of interictal abnormalities in intracranial EEG by constructing a normative map of brain dynamics and quantitatively accounting for the range of healthy brain dynamics. The study finds that regions spared by surgery are more abnormal than resected regions, which can differentiate patient outcomes.
Article
Clinical Neurology
Fabio A. Nascimento, Jaden D. Barfuss, Alex Jaffe, M. Brandon Westover, Jin Jing
Summary: This study designed an algorithm to quantify the six IFCN criteria for identifying interictal epileptiform discharges (IEDs) and estimate the likelihood of a candidate IED being epileptiform. The model's performance was excellent but lower than human experts or a deep neural-network model. The six features of candidate IEDs were of different importance in determining their epileptiform nature, with waveform asymmetry being the most important and duration being the least discriminative. This model may assist clinical electroencephalographers in decision-making and trainees in learning to identify IEDs.
CLINICAL NEUROPHYSIOLOGY
(2023)
Review
Clinical Neurology
Hernan Nicolas Lemus, Rani A. Sarkis
Summary: Alzheimer's disease (AD) is a common type of dementia and currently has no cure. Interictal epileptiform discharges (IEDs) in AD patients are markers of a more aggressive disease course, but there are challenges in standardizing the definition and capturing methods of IEDs. IEDs are an attractive treatment target, but there is uncertainty about when to treat them, the optimal drugs and doses, and the impact of treatment on the disease course.
FRONTIERS IN NEUROLOGY
(2023)
Article
Multidisciplinary Sciences
Marisol Soula, Anna Maslarova, Ryan E. Harvey, Manuel Valero, Sebastian Brandner, Hajo Hamer, Antonio Fernandez-Ruiz, Gyorgy Buzsaki
Summary: Interictal epileptiform discharges (IEDs) are common electrophysiological events observed in epilepsy and other neurological diseases. This study characterizes and compares IEDs in human epilepsy patients and AD transgenic mice, finding similar features and effects on the hippocampal circuit. The findings suggest that IEDs may play a role in cognitive deficits and memory interference.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Clinical Neurology
Simon Henin, Anita Shankar, Helen Borges, Adeen Flinker, Werner Doyle, Daniel Friedman, Orrin Devinsky, Gyorgy Buzsaki, Anli Liu
Summary: The spatiotemporal characteristics of cortical high-gamma activity, hippocampal ripple activity, and interictal epileptiform discharges have a significant impact on memory performance during an associative memory task, particularly in the hippocampal region. Interictal epileptiform discharges may impair associative memory by disrupting physiological activity, making them a promising therapeutic target for memory remediation in patients with epilepsy.
Article
Clinical Neurology
Anca A. Arbune, Pirgit Meritam Larsen, Stephan Wustenhagen, Daniella Terney, Elena Gardella, Sandor Beniczky
Summary: The study found that more than one third of epileptiform EEG discharges showed a decrease in spiking patterns during seizures, suggesting a potential anticonvulsive function, while the majority of discharges increased in association with seizures.
CLINICAL NEUROPHYSIOLOGY
(2021)
Article
Engineering, Biomedical
Ana Maria Amaro de Sousa, Michel J. A. M. van Putten, Stephanie van den Berg, Maryam Amir Haeri
Summary: Interictal discharges are important signatures of epilepsy and their detection can assist in epilepsy diagnostics. This study explored unsupervised and semi-supervised deep learning approaches for the automatic detection of these discharges in EEG recordings. The best performance was achieved using a semi-supervised approach, with a sensitivity of 81.9% and specificity of 91.7%.
BIOMEDICAL SIGNAL PROCESSING AND CONTROL
(2024)
Article
Clinical Neurology
Noa Cohen, Yoram Ebrahimi, Mordekhay Medvedovsky, Guy Gurevitch, Orna Aizenstein, Talma Hendler, Firas Fahoum, Tomer Gazit
Summary: Polymicrogyria is a common brain malformation that can lead to epileptic seizures. By tracking BOLD activations over time, researchers have found that early hemodynamic activity may provide important information to help localize the source of epileptic activity in patients with PMG. The development of IEDs within a small area of the PMG lesion with subsequent wider engagement of brain structures may explain the difficulty in detecting them on scalp EEG.
FRONTIERS IN NEUROLOGY
(2021)
Article
Clinical Neurology
Sulaiman I. Abuhaiba, Isabel C. Duarte, Joo Castelhano, Ana Dionisio, Francisco Sales, Richard Edden, Miguel Castelo-Branco
Summary: This study investigated the antiepileptic effects of cathodal transcranial direct current stimulation (c-tDCS) and its mechanisms of action on neurotransmitters and brain metabolites. The results showed that real c-tDCS decreased the number of epileptiform discharges and reduced GABA concentration in the epileptogenic zone. These findings provide insights into the mechanisms of action of tDCS for epilepsy treatment.
FRONTIERS IN NEUROLOGY
(2022)
Article
Clinical Neurology
Vikram R. Rao, Marc Leguia, Thomas K. Tcheng, Maxime O. Baud
Summary: This study examines the factors influencing seizure timing from a modern perspective, demonstrating that seizures are organized over multiple timescales and presenting new evidence for circadian, multidien, and circannual variation in seizure activity at different periods. The modulation of seizure timing by multiscale temporal variables has significant implications for diagnosis and therapy in clinical epilepsy. Uncovering the mechanistic basis for seizure cycles, especially factors governing multidien periodicity, will be a major focus of future research.
Article
Mathematics, Applied
Marc G. Leguia, Vikram R. Rao, Jonathan K. Kleen, Maxime O. Baud
Summary: Research shows that only time frequency analysis of continuous recordings of a related bio-marker reveals the full extent of cyclical behavior in events. By testing the sensitivity of both methods to non-stationarity in the underlying cycle, the second method demonstrates greater robustness when tested against surrogate time-series.
Article
Clinical Neurology
Jonathan K. Kleen, Benjamin A. Speidel, Maxime O. Baud, Vikram R. Rao, Simon G. Ammanuel, Liberty S. Hamilton, Edward F. Chang, Robert C. Knowlton
Summary: This study introduces a new approach to translate intracranial EEG recordings of seizure activity into 3D videos, aiding medical professionals in better understanding the location and spread of epileptic foci with high accuracy. The method can be applied in patients with medically refractory epilepsy, serving as a valuable tool for surgical planning.
Article
Clinical Neurology
Timothee Proix, Wilson Truccolo, Marc G. Leguia, Thomas K. Tcheng, David King-Stephens, Vikram R. Rao, Maxime O. Baud
Summary: This study demonstrates the feasibility of forecasting seizure probabilities days in advance using implanted device-recorded multidien IEA cycles. It provides a basis for prospective clinical trials to determine how individuals with epilepsy can benefit from long-term seizure forecasting.
Article
Clinical Neurology
Alexa Pappas, Sanjay Kubsad, Maxime O. Baud, Kyla E. Wright, Devon M. Kollmyer, Nicole M. Warner, Alan M. Haltiner, Ryder P. Gwinn, Michael J. Doherty
Summary: The study on a T1D patient showed a 40-day cycle of interictal and ictal activities, but no similar cycle in glucose levels. Glucose elevations were associated with increases in IEA but not seizures. Frequent seizures did not correlate with obvious glucose level changes.
SEIZURE-EUROPEAN JOURNAL OF EPILEPSY
(2021)
Article
Clinical Neurology
Marc G. Leguia, Ralph G. Andrzejak, Christian Rummel, Joline M. Fan, Emily A. Mirro, Thomas K. Tcheng, Vikram R. Rao, Maxime O. Baud
Summary: This study aimed to establish the prevalence, strength, and temporal patterns of seizure cycles in focal epilepsy patients over timescales of hours to years. The results revealed different types of seizure cycles, with high prevalence of circadian, multidien, and circannual cycles, which can help explain the natural variability in seizure timing.
Review
Clinical Neurology
Philippa J. Karoly, Vikram R. Rao, Nicholas M. Gregg, Gregory A. Worrell, Christophe Bernard, Mark J. Cook, Maxime O. Baud
Summary: This Review provides an overview of the evidence for daily, multi-day, and yearly cycles in epileptic brain activity, discussing the potential clinical applications and highlighting technological advances. The authors address the question of why seizures occur when they occur, synthesizing historical, modern, and animal studies to uncover the mechanistic underpinnings of these cycles.
NATURE REVIEWS NEUROLOGY
(2021)
Article
Biochemistry & Molecular Biology
Liberty S. Hamilton, Yulia Oganian, Jeffery Hall, Edward F. Chang
Summary: This study demonstrates that cortical processing in the human auditory cortex is not serially hierarchical, but instead exhibits parallel and independent information processing. The primary and nonprimary auditory cortices have distinct roles in speech perception, with the nonprimary cortex playing an essential independent role.
Article
Neurosciences
Manuel R. Mercier, Anne-Sophie Dubarry, Francois Tadel, Pietro Avanzini, Nikolai Axmacher, Dillan Cellier, Maria Del Vecchio, Liberty S. Hamilton, Dora Hermes, Michael J. Kahana, Robert T. Knight, Anais Llorens, Pierre Megevand, Lucia Melloni, Kai J. Miller, Vitoria Piai, Aina Puce, Nick F. Ramsey, Caspar M. Schwiedrzik, Sydney E. Smith, Arjen Stolk, Nicole C. Swann, Mariska J. Vansteensel, Bradley Voytek, Liang Wang, Jean-Philippe Lachaux, Robert Oostenveld
Summary: Intracranial electroencephalography (iEEG) provides a detailed understanding of the human brain. This article critically reviews iEEG research practices, provides guidelines for newcomers, and addresses issues faced by experienced researchers. The paper covers data collection, electrode localization, preprocessing steps, signal analysis methods, statistical approaches, and unique perspectives on iEEG research. A glossary is also provided for consistent terminology.
Article
Clinical Neurology
Alexander B. Silva, Matthew K. Leonard, Yulia Oganian, Emma D'Esopo, Devon Krish, Brandon Kopald, Edwina B. Tran, Edward F. Chang, Jonathan K. Kleen
Summary: This study highlights the significant role of interictal discharges in word-finding difficulties in patients with epilepsy, acting through multiple cognitive mechanisms. The spikes in the medial temporal lobe are particularly notable for adult focal epilepsy patients. In addition to treating seizures, modulating interictal discharges may be an opportunity to address memory and language impairments in epilepsy.
Editorial Material
Clinical Neurology
Jonathan K. Kleen, Kathryn A. Davis
Summary: Do transient bursts of interictal epileptiform activity have a clinically relevant effect on cognition? This study examines the impact of such bursts on cognitive impairment and reaction times. Scalp EEG has demonstrated focal effects of discharges within a particular hemisphere or lobe, while recent intracranial work has provided more functional-anatomic detail and mechanistic studies. However, most clinicians still hesitate to treat the interictal EEG without clear quantitative guidance.
Review
Neurosciences
Maxime O. Baud, Kaspar Schindler, Vikram R. Rao
Summary: The cyclical structure of epilepsy has been recently rediscovered through long-term intracranial electroencephalography obtained with implanted devices, providing new insights into the practice and interpretation of conventional EEG. There are caveats to counting epileptiform discharges in short-duration EEG recordings and the limitations of conventional EEG have practical implications for titrating anti-seizure medications and allowing patients to drive. Chronic monitoring of brain activity could greatly improve epilepsy care, and utilizing next-generation devices for chronic EEG could leverage known biomarkers of disease state in an impending paradigm shift in epilepsy care.
CLINICAL NEUROPHYSIOLOGY PRACTICE
(2021)