Scalp high frequency oscillations (HFOs) in absence epilepsy: An independent component analysis (ICA) based approach

Chaitanya, Ganne; Sinha, Sanjib; Mariyappa, N.; Satishchandra, P

doi:10.1016/j.eplepsyres.2015.06.008

Cited by 34 publications

(24 citation statements)

References 32 publications

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“…Epilepsy syndromes during childhood investigated so far are West syndrome, childhood absence epilepsy, Lennox–Gastaut syndrome, idiopathic location-related epilepsies such as rolandic epilepsy or Panayiotopoulos syndrome, electrical status epilepticus during slow wave sleep, and early infantile epileptic encephalopathy. 55–61,74,75 …”

Section: Hfos As Markers Of the Epileptogenic Zonementioning

confidence: 99%

“…Epilepsy syndromes during childhood investigated so far are West syndrome, childhood absence epilepsy, Lennox-Gastaut syndrome, idiopathic location-related epilepsies such as rolandic epilepsy or Panayiotopoulos syndrome, electrical status epilepticus during slow wave sleep, and early infantile epileptic encephalopathy. [55][56][57][58][59][60][61]74,75 A surface EEG study in children with rolandic spikes showed that absence of ripples superimposed on rolandic spikes predicts a benign clinical course, whereas in the presence of several ripples, the child is likely to have more seizures than classical rolandic epilepsy, and pharmacological treatment might be needed. 56 A scalp HFO study in childhood absence epilepsy also confirmed higher HFO rates during ictal generalized spike-wave discharges compared to interictal generalized spike-wave discharges or sporadic spike-wave discharges.…”

Section: Important Aspects Of Hfos In Childrenmentioning

confidence: 99%

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High‐frequency oscillations: The state of clinical research

et al. 2017

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Summary 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 post-surgical 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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Section: Hfos As Markers Of the Epileptogenic Zonementioning

confidence: 99%

Section: Important Aspects Of Hfos In Childrenmentioning

confidence: 99%

High‐frequency oscillations: The state of clinical research

et al. 2017

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“…Recently some groups have tried to study HFOs in scalp electroencephalography (EEG) [26], [27] and magnetoencephalography (MEG) [28]. Since the assumptions made by the Z H 0 are not relative to SEEG, one could easily apply it to EEG or MEG data since they also have a 1/ f α spectrum.…”

Section: Applicationsmentioning

confidence: 99%

Time-Frequency Strategies for Increasing High-Frequency Oscillation Detectability in Intracerebral EEG

Roehri

Lina

Mosher

et al. 2016

IEEE Trans. Biomed. Eng.

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Background High Frequency Oscillations (HFOs) are considered to be highly representative of brain tissues capable of producing epileptic seizures. The visual review of HFOs on intracerebral electroencephalography is time-consuming and tedious, and it can be improved by time-frequency (TF) analysis. The main issue is that the signal is dominated by lower frequencies that mask the HFOs. Our aim was to flatten (i.e. whiten) the frequency spectrum to enhance the fast oscillations while preserving an optimal Signal to Noise Ratio (SNR). Method We investigated 8 methods of data whitening based on either prewhitening or TF normalization in order to improve the detectability of HFOs. We detected all local maxima of the TF image above a range of thresholds in the HFO band. Results We obtained the Precision and Recall curves at different SNR and for different HFO types and illustrate the added value of whitening both in the time-frequency plane and in time domain. Conclusion The normalization strategies based on a baseline and on our proposed method (the “H0 z-score”) are more precise than the others. Significance The H0 z-score provides an optimal framework for representing and detecting HFOs, independent of a baseline and a priori frequency bands.

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“…Recent reports have shown that HFBS can also record with scalp Electrophotography (EEG) [33][34][35][36][37][38][39][40]. Scalp EEG is a non-invasive procedure as compared with intracranial recordings.…”

Section: Editorialmentioning

confidence: 99%