Faculty Opinions recommendation of Value of electrical stimulation and high frequency oscillations (80-500 Hz) in identifying epileptogenic areas during intracranial EEG recordings.

Intracranial electroencephalography (iEEG) is used to localize the focus of seizures and determine vital adjacent cortex before epilepsy surgery. The two most commonly used electrode types are subdural and depth electrodes. Foramen ovale electrodes are less often used. Combinations of electrode types are possible. The choice depends on the presumed focus site. Careful planning is needed before implantation, taking into account the results of noninvasive studies. While subdural recordings allow better mapping of functional cortex, depth electrodes can reach deep structures. There are no guidelines on how to read ictal intracranial EEG recordings, but a focal onset (<5 contacts) and a high-frequency onset herald a good prognosis. High-frequency oscillations have been described as a potential biomarker of the seizure onset zone. Intracranial recordings provide a focal but magnified view of the brain, which is also exemplified by the use of microelectrodes, which allow the recording of single-unit or multi-unit activity.

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Human and automated detection of high-frequency oscillations in clinical intracranial EEG recordings

Clinical Neurophysiology ◽

10.1016/j.clinph.2006.12.019 ◽

2007 ◽

Vol 118 (5) ◽

pp. 1134-1143 ◽

Cited By ~ 158

Author(s):

Andrew B. Gardner ◽

Greg A. Worrell ◽

Eric Marsh ◽

Dennis Dlugos ◽

Brian Litt

Keyword(s):

High Frequency ◽

Automated Detection ◽

Intracranial Eeg ◽

High Frequency Oscillations ◽

Eeg Recordings

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A Neuromorphic Spiking Neural Network Detects Epileptic High Frequency Oscillations in the Scalp EEG

10.21203/rs.3.rs-1061301/v1 ◽

2021 ◽

Author(s):

Karla Burelo ◽

Georgia Ramantani ◽

Giacomo Indiveri ◽

Johannes Sarnthein

Keyword(s):

Low Power ◽

Seizure Frequency ◽

High Frequency ◽

Therapy Monitoring ◽

Non Invasive ◽

Scalp Eeg ◽

High Frequency Oscillations ◽

Eeg Recordings ◽

Active Epilepsy ◽

Wearable Electronic Devices

Abstract Background: Interictal High Frequency Oscillations (HFO) are measurable in scalp EEG. This has aroused interest in investigating their potential as biomarkers of epileptogenesis, seizure propensity, disease severity, and treatment response. The demand for therapy monitoring in epilepsy has kindled interest in compact wearable electronic devices for long- term EEG recording. Spiking neural networks (SNN) have been shown to be optimal architectures for being embedded in compact low-power signal processing hardware. Methods: We analyzed 20 scalp EEG recordings from 11 patients with pediatric focal lesional epilepsy. We designed a custom SNN to detect events of interest (EoI) in the 80-250 Hz ripple band and reject artifacts in the 500-900 Hz band. Results: We identified the optimal SNN parameters to automatically detect EoI and reject artifacts. The occurrence of HFO thus detected was associated with active epilepsy with 80% accuracy. The HFO rate mirrored the decrease in seizure frequency in 8 patients (p = 0.0047). Overall, the HFO rate correlated with seizure frequency (rho = 0.83, p < 0.0001, Spearman’s correlation).Conclusions: The fully automated SNN detected clinically relevant HFO in the scalp EEG. This is a further step towards non-invasive epilepsy monitoring with a low-power wearable device.

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ANALYSIS OF HIGH-RESOLUTION MICROELECTRODE EEG RECORDINGS IN AN ANIMAL MODEL OF SPONTANEOUS LIMBIC SEIZURES

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127409023226 ◽

2009 ◽

Vol 19 (02) ◽

pp. 605-617 ◽

Cited By ~ 6

Author(s):

C. KOMALAPRIYA ◽

M. C. ROMANO ◽

M. THIEL ◽

U. SCHWARZ ◽

J. KURTHS ◽

...

Keyword(s):

Animal Model ◽

High Resolution ◽

High Frequency ◽

Recurrence Time ◽

Very High Frequency ◽

Limbic Seizures ◽

High Frequency Oscillations ◽

Quantification Analysis ◽

Eeg Recordings

We perform a systematic data analysis on high resolution (0.5–12 kHz) multiarray microelectrode recordings from an animal model of spontaneous limbic epilepsy, to investigate the role of high frequency oscillations and the occurrence of early precursors for seizures. Results of spectral analysis confirm the importance of very high frequency oscillations (even greater than 600 Hz) in normal (healthy) and abnormal (epileptic) hippocampus. Furthermore, we show that the measures of Recurrence Quantification Analysis (RQA) and Recurrence Time Statistics (RTS) are successful in indicating, rather uniquely, the onset of ictal state and the occurrence of some warnings/precursors during the pre-ictal state, in contrast to the linear measures investigated.

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