Foramen ovale Recordings: A Presurgical Investigation in Epilepsy

Wieshmann, Udo; Denby, C.; Eldridge, Paul; Roberts, Nicky; Mackay, Clare E.; Webb, J A; Tedman, Brian; Chadwick, David; Smith, David F.

doi:10.1159/000067019

Cited by 20 publications

(8 citation statements)

References 16 publications

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“…All MRI negative patients, and patients in whom there was a concern regarding the concordance of non-invasive results had invasive EEG investigations. Until the year 2000, foramen ovale electrodes were typically used [ 39 , 40 ]. After 2000 we used bitemporal depth electrodes.…”

Section: Methodsmentioning

confidence: 99%

The long-term outcomes of epilepsy surgery

et al. 2018

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ObjectiveDespite modern anti-epileptic drug treatment, approximately 30% of epilepsies remain medically refractory and for these patients, epilepsy surgery may be a treatment option. There have been numerous studies demonstrating good outcome of epilepsy surgery in the short to median term however, there are a limited number of studies looking at the long-term outcomes. The aim of this study was to ascertain the long-term outcome of resective epilepsy surgery in a large neurosurgery hospital in the U.K.MethodsThis a retrospective analysis of prospectively collected data. We used the 2001 International League Against Epilepsy (ILAE) classification system to classify seizure freedom and Kaplan-Meier survival analysis to estimate the probability of seizure freedom.ResultsWe included 284 patients who underwent epilepsy surgery (178 anterior temporal lobe resections, 37 selective amygdalohippocampectomies, 33 temporal lesionectomies, 36 extratemporal lesionectomies), and had a prospective median follow-up of 5 years (range 1–27). Kaplan-Meier estimates showed that 47% (95% CI 40–58) remained seizure free (apart from simple partial seizures) at 5 years and 38% (95% CI 31–45) at 10 years after surgery. 74% (95% CI 69–80) had a greater than 50% seizure reduction at 5 years and 70% (95% CI 64–77) at 10 years. Patients who had an amygdalohippocampectomy were more likely to have seizure recurrence than patients who had an anterior temporal lobe resection (p = 0.006) and temporal lesionectomy (p = 0.029). There was no significant difference between extra temporal and temporal lesionectomies. Hippocampal sclerosis was associated with a good outcome but declined in relative frequency over the years.ConclusionThe vast majority of patients who were not seizure free experienced at least a substantial and long-lasting reduction in seizure frequency. A positive long-term outcome after epilepsy surgery is possible for many patients and especially those with hippocampal sclerosis or those who had anterior temporal lobe resections.

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Section: Methodsmentioning

confidence: 99%

The long-term outcomes of epilepsy surgery

et al. 2018

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“…All 114 patients underwent a standardized pre-surgical work-up including electroencephalogram (EEG), neuropsychology, magnetic resonance imaging (MRI) including quantitative measurements of the hippocampal volume and T2 relaxation time in the majority of patients [7] and Sodium Amytal (Wada) test [8]. In patients in whom the seizure onset could not be localized with scalp EEG, invasive EEG with foramen ovale electrodes was used [9,10], but invasive EEGs were not routinely performed in patients who subsequently underwent an AHE. Patients were offered ATLE if the non-dominant hemisphere was affected or if the entire temporal lobe was atrophic.…”

Section: Methodsmentioning

confidence: 99%

The seizure outcome after amygdalohippocampectomy and temporal lobectomy

Bate

Eldridge

Varma

et al. 2007

Euro J of Neurology

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The aim of this study was to compare the seizure outcome of two different types of epilepsy surgery, selective amygdalohippocampectomy (AHE) and anterior temporal lobectomy (ATLE) in patients with temporal lobe epilepsy. We included 114 patients who had mesio-temporal lobe epilepsy and hippocampal sclerosis or gliosis on histology. Patients had ATLE if the non-dominant hemisphere was affected or if the whole temporal lobe was atrophic. Patients had AHE if the dominant hemisphere was affected. Standardized seizure outcome at 1 year following surgery was used. Overall 40% of the 114 patients who had temporal lobe epilepsy surgery were seizure-free at 1-year (Engel's class Ia). A good outcome (Engel's classes I and II) was significantly more frequent in ATLE than in AHE. (66% and 44%, respectively, P = 0.03). ATLE had a better seizure outcome than AHE.

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“…Fewer contralateral spikes, especially independent ones, were a good prognostic indicator and so was the latency of transhemispheric propagation. When spread occurred within 10 seconds or more, a better outcome after surgery was seen than in patients with more rapid pr~pagation.~~ These observations have subsequently been confirmed by several authors,%-% although Wieshmann et al 57 did not observe additional useful information in patients whose MRI had been negative. Data on morbidity, which is low, were presented by WieseP as well as Pastor et aLSp Zumsteg et al59 investigated the potential use of a distributed source model (low-resolution electromagnetic tomography, LORETA) when scalp averages were time locked to the peak of a FO spike and found a high concordance.…”

Section: Semi-invasive Electrodesmentioning

confidence: 83%

Spikes and Epilepsy

et al. 2009

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Digital EEG analysis provides significantly more information to the clinical electroencephalographer (EEGer) for scalp as well as for intracranial monitoring than is currently being routinely utilized. When modern data analysis software is used, interictal spikes contain considerably more information than had previously been ascribed to them. To optimize the diagnostic value of the EEG, sleep recordings after sleep deprivation is valuable because focal spikes, unless abundant, are relatively rare in the waking state. Recording time should also be sufficiently long to allow spikes to emerge. Spikes are always pathologic and can be associated with impaired cerebral perfusion, metabolic changes and concomitant behavioral changes. They can also be separated into simple and complex forms which may allow prognostic statements. The simplest way to accomplish this is by placing a cursor on the peak of the spike and see whether or not other channels show latency differences. More precise methods are: comparisons of voltage maps with current source density maps, principal component analysis and distinctions between stationary versus moving dipoles. Averaging of spikes is valuable but care must be taken that only those spikes which have the same distribution are averaged, and when the average is obtained only from the spike peak, propagation may already have occurred. It has been recommended that the midpoint of the ascending negative phase be used as the point for averaging. In intracranial recordings the frequencies above the gamma range should also be assessed. Their small electrical field allows a differentiation between locally generated events from those which are volume conducted and can thereby more accurately reflect the epileptogenic zone(s). High frequency activity can also be recorded from foramen ovale electrodes which enhances their diagnostic utility. It is emphasized that for centers which perform pre-surgical evaluations the software supplied by instrument manufacturers is inadequate and needs to be supplemented by additional commercially available programs. Furthermore, archived data should be used for retrospective investigations and follow-up studies of patients who have undergone either excisions, resections, or multiple subpial transections to evaluate the success rates by taking into account all the properties of interictal and ictal recordings which are mentioned in this article.

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Foramen ovale Recordings: A Presurgical Investigation in Epilepsy

Cited by 20 publications

References 16 publications

The long-term outcomes of epilepsy surgery

The long-term outcomes of epilepsy surgery

The seizure outcome after amygdalohippocampectomy and temporal lobectomy

Spikes and Epilepsy

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