Ictal electrocorticographic findings related with surgical outcomes in nonlesional neocortical epilepsy

Park, S.A.; Lim, Sung Ryong; Kim, G.S.; Heo, Kyoung; Park, S.C.; Chang, Jin Woo; Chung, Sang Sup; Choi, Jina; Kim, T.S.; Lee, Ki Young

doi:10.1016/s0920-1211(02)00006-2

Cited by 46 publications

(35 citation statements)

References 16 publications

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“…Our findings are in keeping with previous studies which reported a favorable surgical outcome with ictal rapid-band activity in the intracranial EEG, compared to ictal slowing [30]; ictal rapid-band activity was found to correlate with the highest density of interictal epileptiform discharges on the electrodes involved in the seizure onset, over long periods of intracranial EEG, providing in this way a marker to identify the epileptogenic area.…”

Section: Discussionsupporting

confidence: 92%

Individually tailored extratemporal epilepsy surgery in children: Anatomo-electro-clinical features and outcome predictors in a population of 53 cases

Liava

Francione²,

Tassi³

et al. 2012

Epilepsy & Behavior

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Section: Discussionsupporting

confidence: 92%

Individually tailored extratemporal epilepsy surgery in children: Anatomo-electro-clinical features and outcome predictors in a population of 53 cases

Liava

Francione²,

Tassi³

et al. 2012

Epilepsy & Behavior

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“…This was supported by the observation that a localized seizure onset pattern on ECoG frequently consisted of sustained rhythmic oscillations of beta or faster band, while slow rhythmic oscillations of theta or delta band were noted in surrounding or remote regions [59]. A lack of sustained oscillations of beta or faster band at the ictal onset has been associated with poorer seizure outcome following resective surgery [7, 60]. …”

Section: Significance Of Ictal Discharges Consisting Of Hfos On Ecog mentioning

confidence: 95%

How to establish causality in epilepsy surgery

Asano

Brown

Juhász

2013

Brain and Development

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Focality in electro-clinical or neuroimaging data often motivates epileptologists to consider epilepsy surgery in patients with medically-uncontrolled seizures, while not all focal findings are causally associated with the generation of epileptic seizures. With the help of Hill's criteria, we have discussed how to establish causality in the context of the presurgical evaluation of epilepsy. The strengths of EEG include the ability to determine the temporal relationship between cerebral activities and clinical events; thus, scalp video-EEG is necessary in the evaluation of the majority of surgical candidates. The presence of associated ictal discharges can confirm the epileptic nature of a particular spell and whether an observed neuroimaging abnormality is causally associated with the epileptic seizure. Conversely, one should be aware that scalp EEG has a limited spatial resolution and sometimes exhibits propagated epileptiform discharges more predominantly than in situ discharges generated at the seizure-onset zone. Intraoperative or extraoperative electrocorticography (ECoG) is utilized when noninvasive presurgical evaluation, including anatomical and functional neuroimaging, fails to determine the margin between the presumed epileptogenic zone and eloquent cortex. Retrospective as well as prospective studies have reported that complete resection of the seizure-onset zone on ECoG was associated with a better seizure outcome, but not all patients became seizure-free following such resective surgery. Some retrospective studies suggested that resection of sites showing high-frequency oscillations (HFOs) at >80 Hz on interictal or ictal ECoG was associated with a better seizure outcome. Others reported that functionally-important areas may generate HFOs of a physiological nature during rest as well as sensorimotor and cognitive tasks. Resection of sites showing task-related augmentation of HFOs has been reported to indeed result in functional loss following surgery. Thus, some but not all sites showing interictal HFOs are causally associated with seizure generation. Furthermore, evidence suggests that some task-related HFOs can be transiently suppressed by the prior occurrence of interictal spikes. The significance of interictal HFOs should be assessed by taking into account the eloquent cortex, seizure-onset zone, and cortical lesions. Video-EEG and ECoG generally provide useful but still limited information to establish causality in presurgical evaluation. A comprehensive assessment of data derived from multiple modalities is ultimately required for successful management.

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“…Such incongruity may be found in central-parietal epilepsy (50) and in occipital seizure disorders (51). In a study of nonlesional patients, even sequential spikes constituting an ictal discharge failed to identify the ictal-onset region consistently (52). Thus congruency between spike field and region of principal epileptogenesis in some studies (32,53) may reflect the presence of a lesion as the essential linchpin for the relation.…”

Section: Scalp Eegmentioning

confidence: 99%

Indices of Resective Surgery Effectiveness for Intractable Nonlesional Focal Epilepsy

et al. 2003

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Summary: Among 70 patients with intractable focal epilepsy and no specific lesion, as determined by both MRI (magnetic resonance imaging) and histopathology, outcome after resective surgery was polarized: 26 (37%) became seizure free (SF), and 27 (39%) were not helped. Eighteen (42%) of 43 standard temporal resections rendered patients SF, somewhat more than eight (30%) of 27 other procedures. To seek reliable prognostic factors, the subsequent correlative data compared features of the 26 SF patients with those of the 27 not helped. Although ictal semiology guided the site of surgical resection, it and other aspects of seizure and neurologic history failed to predict surgical outcome. However, two aspects of preoperative scalp EEGs correlated with SF outcomes: (a) among 25 patients in whom >50% of clinical seizures arose from the later resected lobe and no other origins, 18 (72%) became SF compared with seven (28%) of 25 with other ictal profiles; (b) 13 (93%) of 14 temporal lobe patients whose interictal and ictal EEGs lacked features indicative of multifocal epileptogenesis became SF compared with five (33%) of 15 with such components. The considered need for subdural (SD) EEG reduced SF outcome from 18 (90%) of 20 patients without SD to eight (24%) of 33 with SD; this likely reflected an insufficient congruity of ictal semiology and interictal and ictal scalp EEG for localizing epileptogenesis. Within this SD group, >50% of clinical seizure origins from a later resected lobe increased SF outcome somewhat: from two (14%) of 14 without this attribute to six (40%) of 15 with it; 100% of such origins increased SF outcome from two (12%) of 16 to six (46%) of 13.

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Ictal electrocorticographic findings related with surgical outcomes in nonlesional neocortical epilepsy

Cited by 46 publications

References 16 publications

Individually tailored extratemporal epilepsy surgery in children: Anatomo-electro-clinical features and outcome predictors in a population of 53 cases

Individually tailored extratemporal epilepsy surgery in children: Anatomo-electro-clinical features and outcome predictors in a population of 53 cases

How to establish causality in epilepsy surgery

Indices of Resective Surgery Effectiveness for Intractable Nonlesional Focal Epilepsy

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