1
|
Ye H, Ye L, Hu L, Yang Y, Ge Y, Chen R, Wang S, Jin B, Ming W, Wang Z, Xu S, Xu C, Wang Y, Ding Y, Zhu J, Ding M, Chen Z, Wang S, Chen C. Widespread slow oscillations support interictal epileptiform discharge networks in focal epilepsy. Neurobiol Dis 2024; 191:106409. [PMID: 38218457 DOI: 10.1016/j.nbd.2024.106409] [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: 09/24/2023] [Revised: 01/01/2024] [Accepted: 01/09/2024] [Indexed: 01/15/2024] Open
Abstract
Interictal epileptiform discharges (IEDs) often co-occur across spatially-separated cortical regions, forming IED networks. However, the factors prompting IED propagation remain unelucidated. We hypothesized that slow oscillations (SOs) might facilitate IED propagation. Here, the amplitude and phase synchronization of SOs preceding propagating and non-propagating IEDs were compared in 22 patients with focal epilepsy undergoing intracranial electroencephalography (EEG) evaluation. Intracranial channels were categorized into the irritative zone (IZ) and normal zone (NOZ) regarding the presence of IEDs. During wakefulness, we found that pre-IED SOs within the IZ exhibited higher amplitudes for propagating IEDs than non-propagating IEDs (delta band: p = 0.001, theta band: p < 0.001). This increase in SOs was also concurrently observed in the NOZ (delta band: p = 0.04). Similarly, the inter-channel phase synchronization of SOs prior to propagating IEDs was higher than those preceding non-propagating IEDs in the IZ (delta band: p = 0.04). Through sliding window analysis, we observed that SOs preceding propagating IEDs progressively increased in amplitude and phase synchronization, while those preceding non-propagating IEDs remained relatively stable. Significant differences in amplitude occurred approximately 1150 ms before IEDs. During non-rapid eye movement (NREM) sleep, SOs on scalp recordings also showed higher amplitudes before intracranial propagating IEDs than before non-propagating IEDs (delta band: p = 0.006). Furthermore, the analysis of IED density around sleep SOs revealed that only high-amplitude sleep SOs demonstrated correlation with IED propagation. Overall, our study highlights that transient but widely distributed SOs are associated with IED propagation as well as generation in focal epilepsy during sleep and wakefulness, providing new insight into the EEG substrate supporting IED networks.
Collapse
Affiliation(s)
- Hongyi Ye
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Nanhu Brain-computer Interface Institute, Hangzhou, China
| | - Lingqi Ye
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lingli Hu
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuyu Yang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Ge
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ruotong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shan Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bo Jin
- Department of Neurology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjie Ming
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhongjin Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Sha Xu
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cenglin Xu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yao Ding
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junming Zhu
- Department of Neurosurgery and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Meiping Ding
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shuang Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Nanhu Brain-computer Interface Institute, Hangzhou, China.
| | - Cong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| |
Collapse
|
2
|
Yang AI, Raghu ALB, Isbaine F, Alwaki A, Gross RE. Sensing with deep brain stimulation device in epilepsy: Aperiodic changes in thalamic local field potential during seizures. Epilepsia 2023; 64:3025-3035. [PMID: 37607249 DOI: 10.1111/epi.17758] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
OBJECTIVE Thalamic deep brain stimulation (DBS) is an effective therapeutic option in patients with drug-resistant epilepsy. Recent DBS devices with sensing capabilities enable chronic, outpatient local field potential (LFP) recordings. Whereas beta oscillations have been demonstrated to be a useful biomarker in movement disorders, the clinical utility of DBS sensing in epilepsy remains unclear. Our aim was to determine LFP features that distinguish ictal from inter-ictal states, which may aid in tracking seizure outcomes with DBS. METHODS Electrophysiology data were obtained from DBS devices implanted in the anterior nucleus (N = 12) or centromedian nucleus (N = 2) of the thalamus. Power spectra recorded during patient/caregiver-marked seizure events were analyzed with a method that quantitatively separates the oscillatory and non-oscillatory/aperiodic components of the LFP using non-parametric statistics, without the need for pre-specification of the frequency bands of interest. Features of the LFP parameterized using this algorithm were compared with those from inter-ictal power spectra recorded in clinic. RESULTS Oscillatory activity in multiple canonical frequency bands was identified from the power spectra in 86.48% of patient-marked seizure events. Delta oscillations were present in all patients, followed by theta (N = 10) and beta (N = 9). Although there were no differences in oscillatory LFP features between the ictal and inter-ictal states, there was a steeper decline in the 1/f slope of the aperiodic component of the LFP during seizures. SIGNIFICANCE Our work highlights the potential and shortcomings of chronic LFP recordings in thalamic DBS for epilepsy. Findings suggest that no single frequency band in isolation clearly differentiates seizures, and that features of aperiodic LFP activity may be clinically-relevant biomarkers of seizures.
Collapse
Affiliation(s)
- Andrew I Yang
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ashley L B Raghu
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Faical Isbaine
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Abdulrahman Alwaki
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
| |
Collapse
|
3
|
Villamar MF, Ayub N, Koenig SJ. Automated Seizure Detection in Patients with Cardiac Arrest: A Retrospective Review of Ceribell™ Rapid-EEG Recordings. Neurocrit Care 2023; 39:505-513. [PMID: 36788179 DOI: 10.1007/s12028-023-01681-w] [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: 08/10/2022] [Accepted: 01/23/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND In patients with cardiac arrest who remain comatose after return of spontaneous circulation, seizures and other abnormalities on electroencephalogram (EEG) are common. Thus, guidelines recommend urgent initiation of EEG for the evaluation of seizures in this population. Point-of-care EEG systems, such as Ceribell™ Rapid Response EEG (Rapid-EEG), allow for prompt initiation of EEG monitoring, albeit through a reduced-channel montage. Rapid-EEG incorporates an automated seizure detection software (Clarity™) to measure seizure burden in real time and alert clinicians at the bedside when a high seizure burden, consistent with possible status epilepticus, is identified. External validation of Clarity is still needed. Our goal was to evaluate the real-world performance of Clarity for the detection of seizures and status epilepticus in a sample of patients with cardiac arrest. METHODS This study was a retrospective review of Rapid-EEG recordings from all the patients who were admitted to the medical intensive care unit at Kent Hospital (Warwick, RI) between 6/1/2021 and 3/18/2022 for management after cardiac arrest and who underwent Rapid-EEG monitoring as part of their routine clinical care (n = 21). Board-certified epileptologists identified events that met criteria for seizures or status epilepticus, as per the 2021 American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology, and evaluated any seizure burden detections generated by Clarity. RESULTS In this study, 4 of 21 patients with cardiac arrest (19.0%) who underwent Rapid-EEG monitoring had multiple electrographic seizures, and 2 of those patients (9.5%) had electrographic status epilepticus within the first 24 h of the study. None of these ictal abnormalities were detected by the Clarity seizure detection system. Clarity showed 0% seizure burden throughout the entirety of all four Rapid-EEG recordings, including the EEG pages that showed definite seizures or status epilepticus. CONCLUSIONS The presence of frequent electrographic seizures and/or status epilepticus can go undetected by Clarity. Timely and careful review of all raw Rapid-EEG recordings by a qualified human EEG reader is necessary to guide clinical care, regardless of Clarity seizure burden measurements.
Collapse
Affiliation(s)
- Mauricio F Villamar
- Department of Neurology, The Warren Alpert Medical School of Brown University, Providence, RI, USA.
- Department of Medicine, Kent Hospital, Warwick, RI, USA.
| | - Neishay Ayub
- Department of Neurology, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Seth J Koenig
- Department of Medicine, Kent Hospital, Warwick, RI, USA
| |
Collapse
|
4
|
Gupta S, Kadam SD. Interictal Discharges: All Roads Lead to Rome? Epilepsy Curr 2022; 22:252-254. [PMID: 36187148 PMCID: PMC9483753 DOI: 10.1177/15357597221098809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human Interictal Epileptiform Discharges Are Bidirectional Traveling Waves
Echoing Ictal Discharges Smith EH, Liou J-Y, Merricks EM, et al. Elife. 2022;11:e73541.
Published 2022 Jan 20. doi:10.7554/eLife.73541. Interictal epileptiform discharges (IEDs), also known as interictal spikes, are large
intermittent electrophysiological events observed between seizures in patients with
epilepsy. Although they occur far more often than seizures, IEDs are less studied, and
their relationship to seizures remains unclear. To better understand this
relationship, we examined multi-day recordings of microelectrode arrays implanted in
human epilepsy patients, allowing us to precisely observe the spatiotemporal
propagation of IEDs, spontaneous seizures, and how they relate. These recordings
showed that the majority of IEDs are traveling waves, traversing the same path as
ictal discharges during seizures, and with a fixed direction relative to seizure
propagation. Moreover, the majority of IEDs, like ictal discharges, were
bidirectional, with 1 predominant and a second, less frequent antipodal direction.
These results reveal a fundamental spatiotemporal similarity between IEDs and ictal
discharges. These results also imply that most IEDs arise in brain tissue outside the
site of seizure onset and propagate toward it, indicating that the propagation of IEDs
provides useful information for localizing the seizure focus.
Collapse
|
5
|
Westin K, Cooray G, Beniczky S, Lundqvist D. Interictal epileptiform discharges in focal epilepsy are preceded by increase in low-frequency oscillations. Clin Neurophysiol 2022; 136:191-205. [PMID: 35217349 DOI: 10.1016/j.clinph.2022.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Interictal epileptiform discharges (IEDs) constitute a diagnostic signature of epilepsy. These events reflect epileptogenic hypersynchronization. Previous studies indicated that IEDs arise from slow neuronal activation accompanied by metabolic and hemodynamic changes. These might induce cortical inhibition followed hypersynchronization at IED onset. As cortical inhibition is mediated by low-frequency oscillations, we aimed to analyze the role of low-frequency oscillations prior the IED using magnetencephalography (MEG). METHODS Low-frequency (1-8 Hz) oscillations pre-IED ([-1000 milliseconds (ms), IED onset]) were analyzed using MEG in 14 focal epilepsy patients (median age = 23 years, range = 7-46 age). Occurrence of local pre-IED oscillations was analyzed using Beamformer Dynamical Imaging of Coherent Sources (DICS) and event-related desynchronization/synchronization (ERD-ERS) maps constructed using cluster-based permutation tests. The development of pre-IED oscillations was characterized using Hilbert transformation. RESULTS All patients exhibited statistically significant increase in delta (1-4 Hz) and/or theta (4-8 Hz) oscillations pre-IED compared to baseline [-2000 ms, -1000 ms]. Furthermore, all patients exhibited low-frequency power increase up to IED onset. CONCLUSIONS We demonstrated consistently occurring, low-frequency oscillations prior to IED onset. SIGNIFICANCE As low-frequency activity mediates cortical inhibition, our study demonstrates that a focal inhibition precedes hypersynchronization at IED onset.
Collapse
Affiliation(s)
- Karin Westin
- NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden.
| | - Gerald Cooray
- Clinical Neurophysiology, Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Neurophysiology, Great Ormand Street Hospital for Children, London, UK
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark and Danish Epilepsy Centre, Dianalund, Denmark
| | - Daniel Lundqvist
- NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|