Non-harmonicity in high-frequency components of the intra-operative corticogram to delineate epileptogenic tissue during surgery

Geertsema, Evelien E.; Klooster, Maryse A. van ‘t; Klink, Nicole E.C. van; Leijten, Frans S.S.; Rijen, Peter C. van; Visser, Gerhard H.; Kalitzin, Stiliyan; Zijlmans, Maeike

doi:10.1016/j.clinph.2016.11.007

Cited by 14 publications

(22 citation statements)

References 49 publications

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“…46 Poor seizure outcome was associated with high "nonharmonicity" on the postresection electrocorticogram, which implies that residual tissue can generate epileptiform activity. 47 Good seizure outcome has been predicted by a combination of low interictal EEG synchrony outside the seizure onset zone (SOZ) and low delta power (0-4Hz) inside the SOZ. 48 Good seizure outcome was predicted by removal of highly epileptogenic areas derived from mathematical models of interictal EEG functional connectivity.…”

Section: D Visualizationmentioning

confidence: 99%

Getting the best outcomes from epilepsy surgery

Vakharia

Duncan

Witt

et al. 2018

Annals of Neurology

193

139

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Neurosurgery is an underutilized treatment that can potentially cure drug‐refractory epilepsy. Careful, multidisciplinary presurgical evaluation is vital for selecting patients and to ensure optimal outcomes. Advances in neuroimaging have improved diagnosis and guided surgical intervention. Invasive electroencephalography allows the evaluation of complex patients who would otherwise not be candidates for neurosurgery. We review the current state of the assessment and selection of patients and consider established and novel surgical procedures and associated outcome data. We aim to dispel myths that may inhibit physicians from referring and patients from considering neurosurgical intervention for drug‐refractory focal epilepsies. Ann Neurol 2018;83:676–690

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Section: D Visualizationmentioning

confidence: 99%

Getting the best outcomes from epilepsy surgery

Vakharia

Duncan

Witt

et al. 2018

Annals of Neurology

193

139

View full text Add to dashboard Cite

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“…36 HFOs can be distinguished intraoperatively if anesthetics like propofol are temporarily stopped. [42][43][44] Scalp EEG Some EEG textbooks taught us that the skull filters away higher frequencies and it was not expected to find epileptic HFOs with scalp EEG. [38][39][40] Recording and interpreting fast ripples during surgery is feasible, and a first trial testing of the use of HFOs during epilepsy surgery has started.…”

Section: Intraoperative Electrocorticographymentioning

confidence: 99%

“…The speed of review could be increased with the use of (online) automatic HFO detectors (see below), other signal analysis methods, or by evoking high frequency responses with single pulse stimulation. [42][43][44] Scalp EEG Some EEG textbooks taught us that the skull filters away higher frequencies and it was not expected to find epileptic HFOs with scalp EEG. This is not correct, as the skull does not have low-pass filter capacities.…”

Section: Intraoperative Electrocorticographymentioning

confidence: 99%

How to record high‐frequency oscillations in epilepsy: A practical guideline

et al. 2017

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“…The auto-regressive residual modulation (ARRm) provides the amount of non-harmonicity in the signal quantified as the high residual variation after auto-regressive modelling 30,31 . It has been shown that brain tissue with high non-harmonicity corresponds to areas with high frequency oscillations (HFOs) which in turn may be an indication of epileptogenic tissue [38][39][40][41][42] .…”

Section: Auto-regressive Residual Modulationmentioning

confidence: 99%

“…We investigated, in our ground-truth scenario, the performances of different biomarkers that were already used in previous studies [23][24][25][27][28][29][30][31][32][33][34][35] . We defined our biomarker pool with the attempt to be exhaustive according to the three different categories univariate, bivariate and multivariate biomarkers.…”

Section: Introductionmentioning

confidence: 99%

To resect or not to resect? Unbiased performances of single and combined biomarkers in intra-operative corticography for tailoring during epilepsy surgery

Demuru

Kalitzin

Zweiphenning

et al. 2019

Preprint

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Objective:Signal analysis biomarkers, in an intra-operative setting, may be complementary tools to guide and tailor the resection in drug-resistant epilepsy patients. Unbiased assessment of biomarker performances are needed to evaluate their clinical usefulness and translation. We defined a realistic ground-truth scenario and compared the effectiveness of different biomarkers alone and combined to localize epileptogenic tissue. Methods:We investigated the performances of univariate, bivariate and multivariate signal biomarkers applied to 1 minute inter-ictal intra-operative electrocorticography to discriminate between electrodes covering normal or pathologic activity in 47 drug-resistant people with epilepsy (temporal and extra-temporal) who had been seizure-free one year after the operation. Results:The best result using a single biomarker was obtained using the phase-amplitude coupling measure for which the epileptogenic tissue was localized in 16 out of 47 patients. Combining the whole set of biomarkers provided an improvement of the performances: 20 out of 47 patients. Repeating the analysis only on the temporal-lobe resections we reached a sensitivity of 93% (28 out of 30) combining all the biomarkers. Conclusion:We suggest that the assessment of biomarker performances on a ground-truth scenario is required to have a proper estimate on how biomarkers translate into clinical use. Phase-amplitude coupling seems the best performing single biomarker and combining biomarkers improves localization of epileptogenic tissue. However, sensitivity achieved is not adequate for the usage as a tool in the operation theater, but it can improve the understanding of pathophysiological process.

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Non-harmonicity in high-frequency components of the intra-operative corticogram to delineate epileptogenic tissue during surgery

Cited by 14 publications

References 49 publications

Getting the best outcomes from epilepsy surgery

Getting the best outcomes from epilepsy surgery

How to record high‐frequency oscillations in epilepsy: A practical guideline

To resect or not to resect? Unbiased performances of single and combined biomarkers in intra-operative corticography for tailoring during epilepsy surgery

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