Efficacité à long terme de la stimulation intermittente du nerf vague dans les épilepsies pharmaco-résistantes non chirurgicales

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

The impact of epilepsy surgery on mortality.

International audiencePatients with refractory epilepsy suffer from an increased risk of death, primarily due to seizure-related fatalities including sudden unexpected death (SUDEP), which could be conceivably avoided by surgical cure of the epilepsy. Several series have addressed this issue by comparing the mortality rate between medically and surgically treated drug resistant populations, as well as between patients, seizure free and non seizure free post-operatively. Results from some studies suggest that successful temporal lobe surgery reduced the risk of death to that observed in the normal population, whereas patients who continue to suffer recurrent seizures still present an increased standardized mortality ratio (SMR). However, other series have failed to replicate this finding, or found no difference in the overall mortality and SUDEP rates between operated and medically treated patients. All the above studies suffer various types of methodological limitations, hampering any definite conclusion regarding the impact of epilepsy surgery on mortality. However, part of the apparently discordant reported findings might be reconciled through the following framework. Patients who will eventually respond favourably or unfavourably to an anterior temporal lobectomy might already differ in the risk of seizure-related death, pre-operatively. Specifically, patients whose temporal lobe epileptogenic network extends to the perisylvian region (temporal plus epilepsy) appear to be at higher risk of failed TLE surgery, secondary generalised tonic-clonic seizures, ictal apnoea or insula-driven severe cardiac arrhytmias. This population might carry most of the SUDEP burden, both pre- and post-operatively, accounting for the lack of an obvious net reduction of seizure related deaths after temporal lobe surgery. A multicentric study has recently been launched in order to test this hypothesis, and will hopefully help to conclude on the impact of epilepsy surgery on mortality outcome

Sudden unexpected death in epilepsy: from mechanisms to prevention.

International audiencePURPOSE OF REVIEW: To discuss the pathophysiology and potential prevention of sudden unexpected death in epilepsy. RECENT FINDINGS: Long-term electrocardiogram monitoring over several months has detected ictal asystole in three out of 20 (15%) patients with refractory epilepsy, suggesting that high-risk ictal arrhythmias occur in a greater proportion of patients with refractory epilepsy than previously thought. In case-control studies, sudden unexpected death in epilepsy was found to be associated with frequent generalized tonic-clonic seizures and greater ictal maximal heart rate, especially during nocturnal attacks. Conversely, supervision at night was associated with a lower risk of occurrence. The impact of epilepsy surgery on the risk of death and sudden unexpected death in epilepsy remains unclear, with comparable long-term survival in an epilepsy surgery cohort compared with a matched population of patients with refractory epilepsy who did not undergo surgery. Previous results may have been partly confounded by the association observed between preoperative decreased heart rate variability and poor postoperative seizure outcome. SUMMARY: Ictal arrhythmias may represent a more prevalent cause of sudden unexpected death in epilepsy than previously thought. No clear recommendations have emerged from the literature regarding the most appropriate therapeutic strategies to prevent the event, apart from the supervision at night of patients with refractory epilepsy

Foreign language ictal speech automatisms in nondominant temporal lobe epilepsy.

International audienceBACKGROUND: Foreign language ictal speech automatism (FLISA) is a rare ictal sign that has been hitherto reported in five unilingual patients, all right handed men with right temporal lobe epilepsy (TLE), only one of whom has benefited from an intracerebral EEG investigation. METHODS: We report three unilingual French patients who consistently presented English spoken ictal speech automatisms and were investigated with intracerebral EEG recordings. RESULTS: All three patients were right-handed men with nondominant TLE originating in the right amygdala. However, FLISA only occurred when the ictal EEG discharge spread to the ipsilateral temporal neocortex or frontal operculum. In addition, FLISA were emotionally salient, referring to the patient's parents or to the intensity of the ongoing seizure. CONCLUSION: Our findings, together with previously published data, suggest that foreign language ictal speech automatisms are more likely to occur in men with nondominant amygdala onset seizures, an observation that might reflect the sexual dimorphism observed in the right amygdala during emotional processing

Migraine with brainstem aura: Why not a cortical origin?

International audienceBackground Migraine with brainstem aura is defined as a migraine with aura including at least two of the following symptoms: dysarthria, vertigo, tinnitus, hypacusis, diplopia, ataxia and/or decreased level of consciousness. Aim The aim of this study is to review data coming from clinical observations and functional mapping that support the role of the cerebral cortex in the initiation of brainstem aura symptoms. Results Vertigo can result from a vestibular cortex dysfunction, while tinnitus and hypacusis can originate within the auditory cortex. Diplopia can reflect a parieto-occipital involvement. Dysarthria can be caused by dysfunctions located in precentral gyri. Ataxia can reflect abnormal processing of vestibular, sensory, or visual inputs by the parietal lobe. Alteration of consciousness can be caused by abnormal neural activation within specific consciousness networks that include prefrontal and posterior parietal cortices. Conclusion Any symptom of so-called brainstem aura can originate within the cortex. Based on these data, we suggest that brainstem aura could have a cortical origin. This hypothesis would explain the co-occurrence of typical and brainstem aura during attacks and would fit with the theory of cortical spreading depression. We propose that migraine with brainstem aura should be classified as a typical migraine aura

Indications and limits of stereoelectroencephalography (SEEG)

International audienceEpilepsy surgery is now an accepted treatment to achieve seizure control in carefully selected patients, both children and adults, suffering from drug-resistant focal epilepsy. Although surgical strategies can often be defined on the basis of non-invasive diagnostic procedures, and despite the recent advances in this field, an increasing number of more complex cases requires invasive EEG (iEEG) to provide precise information on the localization of the epileptogenic zone (EZ), its relationships with eloquent cortex (EC), and the feasibility of a tailored surgical resection. Stereoelectroencephalography (SEEG) is one of the iEEG techniques currently used in the presurgical work-up, and it is well-distinguished from other invasive techniques, such as subdural grids and strips. SEEG depth electrodes enable exploration of deeply located structures and lesions, and of buried cortex, which are not easily assessable by subdural or other iEEG methods. Simultaneous recording of SEEG signals from deep and superficial brain structures allows, when the position of each electrode is precisely determined, delineation of a three-dimensional, spatial and temporal organization of epileptic activities. In the following chapter we discuss some specific indications (temporal or extra-temporal, lesional or non-lesional epilepsies) as well as the limits of the SEEG technique, with respect to some epileptological issues during presurgical evaluation

Surgical techniques: Stereoelectroencephalography-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC)

International audienceStereoelectroencephalography-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC) consists of coupling SEEG investigation with RF-TC stereotactic lesioning directly through the recording electrodes. In this systematic review the surgical technique, indications, and outcomes are described. Maximum accuracy is reached when a frame-based procedure with a robotic assistance and a per-operative vascular X-ray imaging are performed. Monitoring of the lesioning procedure based on the impedance, a sharp modification of which indicates that the thermocoagulation has reached its maximum volume, allows the optimization of the lesion size. The first indication concerns patients in whom a SEEG is required to determine whether surgery is feasible and in whom resection is indeed possible. Even if surgery is performed owing to insufficient efficacy of SEEG-guided RF-TC, the procedure remains interesting owing to its high positive predictive value for good outcome after surgery. The second indication concerns patients in whom phase I non-invasive investigations have concluded to surgical contraindication and who may still undergo SEEG in a purely therapeutic perspective (small deep zones inaccessible to surgery and network nodes of large epileptic networks). Lastly, SEEG-guided RF-TC can be considered as a first-line treatment for periventricular nodular heterotopia (PNH). Independently of indication, the overall seizure-free rate is 23% and the responder rate is 58%. The best results are obtained for PNH (38% seizure-free and 81% responders), while the worst results have been reported for temporal lobe-epilepsy in a dedicated study. The overall complication rate is 2.5%. More evidence is needed to help determine the exact place of SEEG-guided RF-TC in the surgical management algorithm

Peri‐ictal hypoxemia during temporal lobe seizures: A <scp>SEEG</scp> study

International audienceFocal seizures originating from the temporal lobe are commonly associated with periictal hypoxemia (PIH). During the course of temporal lobe seizures, epileptic discharges often not only spread within various parts of the temporal lobe but also possibly insula and frontal lobe. The link between spatial propagation of the seizure discharges and PIH is still unclear. The present study investigates the involvement of several brain structures including medial temporal structures, temporal pole, anterior insula, and frontal cortex in the occurrence of PIH. Using quantitative indice

Visceral and emotional responses to direct electrical stimulations of the cortex

Abstract Objective Visceral sensations are bodily symptoms which are component manifestations of emotions frequently reported during epileptic seizures. Nowadays, the underlying mechanism and location of brain areas involved in the processing of these sensations remain unclear. Our objectives were to characterize the type and frequency of visceral and emotional responses evoked by electrical stimulations, to produce a mapping of brain structures involved in their processing, and to assess the link between visceral sensations and emotional feelings. Methods We reviewed 12,088 bipolar stimulations performed in 203 patients during the presurgical evaluation of drug refractory epilepsy. Responses to stimulation were divided into viscero‐sensitive, viscero‐vegetative, and emotional sensations. Univariate analysis and conditional logistic regression were used to assess the association between visceral and emotional sensations and localization of the stimulated contacts. Results In total, 543 stimulations evoked visceral and emotional sensations. Stimulations of operculo‐insulolimbic structures (amygdala, anterior and posterior insula, anterior and mid‐cingulate cortex, hippocampus, parahippocampus, temporal pole, frontal and parietal operculum) were significantly more associated with visceral and emotional sensations than all other cortical regions. Preferential implication of certain brain structures, depending on the type of visceral responses was evidenced: temporo‐mesial structures, insula, and frontoparietal operculum for viscero‐sensitive sensations; amygdala, insula, anterior and mid‐cingulate cortex, and temporal pole for viscero‐vegetative sensations; temporo‐mesial structures, anterior cingulate cortex, and frontal operculum for emotional sensations. Interpretation Our data can help to guide SEEG explorations when visceral or emotional symptoms are part of the ictal semiology. They also bring some insights into the mechanisms of visceroception and the functional significance of the co‐localization of visceral and emotional representations in the human brain

Peri‐ictal hypoxemia during temporal lobe seizures: A <scp>SEEG</scp> study

International audienceFocal seizures originating from the temporal lobe are commonly associated with periictal hypoxemia (PIH). During the course of temporal lobe seizures, epileptic discharges often not only spread within various parts of the temporal lobe but also possibly insula and frontal lobe. The link between spatial propagation of the seizure discharges and PIH is still unclear. The present study investigates the involvement of several brain structures including medial temporal structures, temporal pole, anterior insula, and frontal cortex in the occurrence of PIH. Using quantitative indice