Occurrence of scalp-fast oscillations among patients with different spiking rate and their role as epileptogenicity marker

Melani, Federico; Zelmann, Rina; Dubeau, François; Gotman, Jean

doi:10.1016/j.eplepsyres.2013.06.003

Cited by 77 publications

(94 citation statements)

References 22 publications

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“…However, recent work has detected spontaneous ripple-frequency HFOs associated with spikes in scalp EEG from children with continuous spike and wave during slow wave sleep [115]. Two subsequent studies detected gamma-and ripple-frequency HFOs in the scalp EEG of adults with epilepsy [116,117]. In these studies, HFOs were often associated with IIS, but some occurred independently of IIS, and rates of HFO and IIS were higher inside than outside the SOZ.…”

Section: Interictal Hfosmentioning

confidence: 99%

Electrophysiological Biomarkers of Epilepsy

2014

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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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Section: Interictal Hfosmentioning

confidence: 99%

Electrophysiological Biomarkers of Epilepsy

2014

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“…A recent study showed that interictal surface ripples decrease after treatment with ACTH in children with West Syndrome (Kobayashi et al, 2015). Co-occurrence of ripples with epileptic spikes is reported in 44-64% of all ripples in intracranial and surface recordings (Melani et al, 2013;Andrade-Valenca et al, 2011;Urrestarazu et al, 2007;Jacobs et al, 2009;Wang et al, 2013). Ripples co-occurring with a spike are more related to the seizure onset zone than ripples without a spike (Wang et al, 2013).…”

Section: Introductionmentioning

confidence: 96%

“…This increases the population for whom HFO analysis is available, beyond the small group of drug-resistant focal epilepsy patients who are candidates for surgery with intracerebral electrodes. Reports describe 50-100 Hz activity in ictal recordings (Kobayashi et al, 2004(Kobayashi et al, , 2009, ripples in interictal EEG in adults with focal epilepsy (Andrade-Valenca et al, 2011;Melani et al, 2013;Zelmann et al, 2013), in children with continuous spike and wave in slow-wave sleep (Kobayashi et al, 2010), and idiopathic partial epilepsy (Kobayashi et al, 2011). A recent study showed that interictal surface ripples decrease after treatment with ACTH in children with West Syndrome (Kobayashi et al, 2015).…”

Section: Introductionmentioning

confidence: 96%

Relationships between interictal epileptic spikes and ripples in surface EEG

Klink

Frauscher

Zijlmans

et al. 2016

Clinical Neurophysiology

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“…Then, interictal HFOs were identified in the scalp EEG of patients with focal epilepsy with higher rates inside the SOZ 28 . Interestingly, HFOs were more frequent in patients with high numbers of interictal epileptiform discharges (IEDs), and they were found to be more specific than IEDs for the SOZ 29 , highlighting the relation of HFOs with epileptogenicity.…”

Section: Introductionmentioning

confidence: 99%

“…A recent study proposed that HFOs recorded non-invasively with scalp EEG represent the sum of activity of multiple spatially distributed focal and coherent sources 60 . So far, few studies 28,29,37,38,60 managed to show that HFOs can be detected non-invasively using scalp EEG and MEG; even fewer localized this activity by solving the inverse problem [37][38] .…”

Section: Significance Of the Technique With Respect To Existing/altermentioning

confidence: 99%

Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy

Papadelis

Tamilia

Stufflebeam

et al. 2016

JoVE

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Crucial to the success of epilepsy surgery is the availability of a robust biomarker that identifies the Epileptogenic Zone (EZ). High Frequency Oscillations (HFOs) have emerged as potential presurgical biomarkers for the identification of the EZ in addition to Interictal Epileptiform Discharges (IEDs) and ictal activity. Although they are promising to localize the EZ, they are not yet suited for the diagnosis or monitoring of epilepsy in clinical practice. Primary barriers remain: the lack of a formal and global definition for HFOs; the consequent heterogeneity of methodological approaches used for their study; and the practical difficulties to detect and localize them noninvasively from scalp recordings. Here, we present a methodology for the recording, detection, and localization of interictal HFOs from pediatric patients with refractory epilepsy. We report representative data of HFOs detected noninvasively from interictal scalp EEG and MEG from two children undergoing surgery.The underlying generators of HFOs were localized by solving the inverse problem and their localization was compared to the Seizure Onset Zone (SOZ) as this was defined by the epileptologists. For both patients, Interictal Epileptogenic Discharges (IEDs) and HFOs were localized with source imaging at concordant locations. For one patient, intracranial EEG (iEEG) data were also available. For this patient, we found that the HFOs localization was concordant between noninvasive and invasive methods. The comparison of iEEG with the results from scalp recordings served to validate these findings. To our best knowledge, this is the first study that presents the source localization of scalp HFOs from simultaneous EEG and MEG recordings comparing the results with invasive recordings. These findings suggest that HFOs can be reliably detected and localized noninvasively with scalp EEG and MEG. We conclude that the noninvasive localization of interictal HFOs could significantly improve the presurgical evaluation for pediatric patients with epilepsy.

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Occurrence of scalp-fast oscillations among patients with different spiking rate and their role as epileptogenicity marker

Cited by 77 publications

References 22 publications

Electrophysiological Biomarkers of Epilepsy

Electrophysiological Biomarkers of Epilepsy

Relationships between interictal epileptic spikes and ripples in surface EEG

Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy

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