CONFISEP: Impact of the Covid-19 pandemic lockdown on patients with multiple sclerosis in the north of France.

We performed an online survey to assess lockdown impact in 176 patients with multiple sclerosis (PwMS) in the north of France. Access to healthcare was reduced for 38% of PwMS, mainly in physiotherapy, general practitioners and neurologists. 49.2% have implemented self-rehabilitation programs. Medical support was maintained for 39.2% through teleconsultations. 76.2% reported a negative impact of lockdown related to worsen disability. 45.5% expressed beneficial effects like strengthening family relationships, and reduced fatigue. Previous studies have found the same results on disability and discontinuation of care. However, even if this period has been challenging for PwMS, most of them have shown excellent adaptability.

Malformations of cortical development: New surgical advances.

Epilepsy related to malformations of cortical development is frequently drug resistant or requires heavy medication, therefore surgery is key in their management. The role of stereotactic surgery has recently changed the diagnosis and treatment of focal cortical dysplasias (FCD), hypothalamic hamartomas (HH) and periventricular nodular heterotopias (PNH). In HH, radiosurgery using Gammaknife® leads to 60 % of seizure control and is associated with excellent neuropsychological results without significant endocrine function impairment. The seizure control rate is even higher (more than 80 %) with monopolar multiple stereotactic thermocoagulations and Laser interstitial Thermal Therapy (LiTT). While the first technique is associated with a 2 % complications rate (but with excellent neuropsychological outcomes), the latest has up to 22 % side effects in some series. All three of these techniques have encouraging results, but controlled studies are still lacking to provide evidence-based new therapeutic algorithms. With regard to the PNH, surgical management has long been limited by the depth of the lesions and their close anatomical relations with the functional brain connectome. Stereotactic approaches required to perform a SEEG, to locate the part of the PNH responsible for the seizure onset, are later followed by a stereotactic lesioning procedure, therefore doubling the bleeding risk. That is why SEEG-guided radiofrequency-thermocoagulation (SEEG guided-RF-TC), which makes it possible to perform these two steps in a single procedure, was considered as a promising option. A recent meta-analysis confirmed this intuition and reported 38 % of seizure-free patients and 81 % of responders with only 0.3 % of complications, making this approach the first treatment line, followed by LiTT. Among the multiple advances in the FCD identification by non-invasive investigations, a new modality of per-operative diagnostic procedure, the three-dimensional electrocorticography may lead to simplify the preoperative investigation and enhance the accuracy of FCD delineation. Evidence is nevertheless still insufficient to validate this promising concept. Conventional surgical resection has also been concerned by significant conceptual advances during the past few years, in particular with the development of the hodotopic approach, initially in oncologic surgery. Associated with a better understanding of neuroplasticity in epilepsy and the setting up of functional mapping during SEEG or during awake surgery, the possibility of surgical resections grew up. A short-term perspective in this field, when surgical resection remains impossible, would be to target crucial nodes of the epileptic network, distinct from the core functional connectome.

Semiology of insular lobe seizures.

After the early attempts of intra-operative electrocorticography and insulectomy in the 1950s, the notion of insular lobe seizures was largely forgotten for decades. It is only since the late 1990s that the recent technique of stereo-electroencephalography (SEEG) enabled preoperative diagnosis of insular origin seizures and thus gave rise to a renewed interest for this ill-defined electroclinical entity. Owing to the multiple functional roles of insula and its extensive connectivity with adjacent as well as distant brain structures, insular lobe seizures present with a combination or series of diverse subjective and objective symptoms. In this review, we summarize current knowledge on the semiology of insular origin seizures. The following two distinct forms of clinical presentation have been recognized: 1) Seizures with predominant insulo-perisylvian symptoms, most notably paraesthesia and cervico-laryngeal discomfort. The former typically involves a large/bilateral cutaneous territory and can be perceived as cold, hot, or painful sensations. The latter ranges from slight dyspnea to strong sensation of strangulation. Other symptoms include epigastric discomfort/nausea, hypersalivation, auditory, vestibular, gustatory, and aphasic symptoms. 2) Nocturnal hyperkinetic seizures with/without tonic elevation of upper limbs, masquerading as fronto-mesial seizures. Patients are usually not fully aware of their symptoms despite preserved contact and organized behavior to others. Ipsilateral eye blinking can be observed. These two patterns often occur in succession or simultaneously. This characteristic combination and progression of ictal symptoms orients us strongly towards an insular origin of seizure, a better understanding of which is a crucial key to further optimize modern SEEG strategy.

Resective surgery in tuberous Sclerosis complex, from Penfield to 2018: A critical review.

Medically treated patients suffering from tuberous sclerosis complex (TSC) have less than 30% chance of achieving a sustained remission. Both the international TSC consensus conference in 2012, and the panel of European experts in 2012 and 2018 have concluded that surgery should be considered for medically refractory TSC patients. However, surgery remains currently underutilized in TSC. Case series, meta-analyses and guidelines all agree that a 50 to 60% chance of long-term seizure freedom can be achieved after surgery in TSC patients and a presurgical work-up should be done as early as possible after failure of two appropriate AEDs. The presence of infantile spasms, the second most common seizure type in TSC, had initially been a barrier to surgical planning but is now no longer considered a contraindication for surgery in TSC patients. TSC patients undergoing presurgical evaluation range from those with few tubers and good anatomo-electro-clinical correlations to patients with a significant "tuber burden" in whom the limits of the epileptogenic zone is much more difficult to define. Direct surgery is often possible in patients with a good electro-clinical and MRI correlation. For more complex cases, invasive monitoring is often mandatory and bilateral investigations can be necessary. Multiple non-invasive tools have been shown to be helpful in determining the placement of these invasive electrodes and in planning the resection scheme. Additionally, at an individual level, multimodality imaging can assist in identifying the epileptogenic zone. Increased availability of investigations that can be performed without sedation in young and/or cognitively impaired children such as MEG and HR EEG would most probably be of great benefit in the TSC population. Of those selected for invasive EEG, rates of seizure freedom following surgery are close to cases where invasive monitoring is not required, strengthening the important and efficient role of intracranial investigations in drug-resistant TSC associated epilepsy.

SEEG-guided RF-thermocoagulation of epileptic foci: a therapeutic alternative for drug-resistant non-operable partial epilepsies.

BACKGROUND: Previous literature includes numerous reports of acute stereotactic ablation for epilepsy. Most reports focus on amygdalotomies or amygdalohippocampotomies, some others focus on various extra-limbic targets. These stereotactic techniques proved to have a less favourable outcome than that of standard surgery, so that their rather disappointing benefit/risk ratio explains why they have been largely abandoned. However, depth electrode recordings may be required in some cases of epilepsy surgery to delineate the best region of cortical resection. We usually implant depth electrodes according to Talairach's stereo electroencephalography (SEEG) methodology. Using these chronically implanted depth electrodes, we are able to perform radiofrequency (RF)-thermolesions of the epileptic foci. This paper reports the technical data required to perform such multiple cortical thermolesions, as well as the results in terms of seizure outcome in a group of 41 patients. TECHNICAL DATA: Lesions are placed in the cortex areas showing either a low amplitude fast pattern or spike-wave discharges at the onset of the seizures. Interictal paroxysmal activities are not considered for planning thermocoagulation sites. All targets are first functionally evaluated using electrical stimulation. Only those showing no clinical response to stimulation are selected for thermolesion, including sites located inside or near primary functional area. Lesions are performed using 120mA bipolar current (50 V), applied for 10-30 sec. Each thermocoagulation produces a 5-7mm diameter cortical lesion. A total of 2-31 lesions were performed in each of the 41 patients. Lesions are placed without anaesthesia. RESULTS: 20 patients (48.7%) experienced a seizure frequency decrease of at least 50% that was more than 80% in eight of them. One patient was seizure free after RF thermocoagulation. In 21 patients, no significant reduction of the seizure frequency was observed. Amongst the characteristics of the disease (age and sex of the patient, lobar localization of the EZ) and the characteristics of the thermocoagulations (topography, lateralization, number, morphology of the lesions on MRI) no factor was significantly linked to the outcome. However, the best results were clearly observed in epilepsies symptomatic of a cortical development malformation (CDM), with 67% of responders in this group of 20 patients (p = 0.052). Three transient post-procedure side-effects, consisting of paraesthetic sensations in the mouth (2 cases), and mild apraxia of the hand, were observed. CONCLUSION: SEEG-guided-RF-thermolesioning is a safe technique. Our results indicate that such lesions can lead to a significant reduction of seizure frequency. Our experience suggests that SEEG-guided RF thermocoagulation should be dedicated to drug-resistant epileptic patients for whom conventional resection surgery is risky or contra-indicated on the basis of invasive pre-surgical evaluation, particularly those suffering from epilepsy symptomatic of cortical development malformation.

[Evacuation of chronic subdural hematomas with the Twist-Drill technique: Results of a randomized prospective study comparing 48-h and 96-h drainage duration]. / Evacuation des hématomes sous-duraux chroniques par la technique du twist-drill. Résultats d'une étude randomisée prospective entre un drainage de 48 heures et un drainage de 96 heures.

BACKGROUND AND PURPOSE: Technical modalities for the evacuation of chronic subdural hematomas are still controversial. The Twist-Drill technique with closed-system drainage is becoming more widely used, but the influence of drainage duration on outcome has not been studied yet and therefore is still being debated. METHODS: A prospective randomized study was conducted, comparing the results between two drainage durations. Forty-eight hours (Group I; n=35 patients) and 96 h (Group II; n=30 patients). RESULTS: The two groups had almost identical characteristics due to randomization. The mean volume of liquid drained was 120 ml in the first group and 285 ml in the second, a statistically significant difference. The rate of incomplete evacuation versus the rate of recurrence did not show any significant difference between Group I (5.7 % and 11.4 %, respectively) and Group II (3.3 % and 10 %, respectively). The rate of postoperative complications was 10.7 % in Group I but 26.9 % in Group II, with a respective 3.8 % and 11.4 % mortality rate, proving a statistically significant difference. Clinical improvement observed at discharge was 85.7 % and 84.6 % in Group I and Group II, respectively. CONCLUSION: With comparable recurrence and improvement rates, our study demonstrates that it is much more advantageous to remove the catheter at 48 h than leave it in for a longer duration. Not only is bed rest reduced, but the rate of morbidities is also significantly decreased.

Somatotopic organization of pain responses to direct electrical stimulation of the human insular cortex.

The question whether pain encoding in the human insula shows some somatotopic organization is still pending. We studied 142 patients undergoing depth stereotactic EEG (SEEG) exploration of the insular cortex for pre-surgical evaluation of epilepsy. 472 insular electrical stimulations were delivered, of which only 49 (10.5%) elicited a painful sensation in 38 patients (27%). Most sites where low intensity electric stimulation produced pain, without after-discharge or concomitant visually detectable change in EEG activity outside the insula, were located in the posterior two thirds of the insula. Pain was located in a body area restricted to face, upper limb or lower limb for 27 stimulations (55%) and affected more than one of these regions for all others. The insular cortex being oriented parallel to the medial sagittal plane we found no significant difference between body segment representations in the medio-lateral axis. Conversely a somatotopic organization of sites where stimulation produced pain was observed along the rostro-caudal and vertical axis of the insula, showing a face representation rostral to those of upper and lower limbs, with an upper limb representation located above that of the lower limb. These data suggest that, in spite of large and often bilateral receptive fields, pain representation shows some degree of somatotopic organization in the human insula.

SEEG-guided thermocoagulations: a palliative treatment of nonoperable partial epilepsies.

OBJECTIVE: Intracranial stereotactic EEG recordings (SEEG) in presurgical epilepsy assessment are currently carried out in our department. The SEEG method generally used for exploration can also be used to perform radiofrequency thermocoagulations (RFTC) of the epileptic foci. To assess the indications of the RFTC procedure in the therapeutic arsenal of drug-resistant epilepsies, we report the results obtained in 41 patients to whom RFTC was proposed as a first therapeutic step before surgery or as a palliative treatment when surgery was not possible. METHODS: RFTC were produced by applying a 50-volt, 110 mA current, during 10-30 seconds within the epileptogenic zone, as identified by the SEEG investigation. Two to 31 RFTC (mean, 12) were performed per patient. The median follow-up was 19 months (range: 4 to 72). RESULTS: Twenty patients (48.7%) experienced a seizure frequency decrease of at least 50%, which was over 80% in eight of them. One patient was seizure-free. The tolerance was excellent. A total of 67% of the 21 patients presenting a cortical development malformation benefited from RFTC (p = 0.052). In the group of noneligible patients for resective surgery (n = 13), six were responders to SEEG-guided RFTC and one of them was seizure-free. CONCLUSIONS: This study suggests that stereotactic EEG-guided radiofrequency thermocoagulations can be proposed only as a palliative procedure, able to bring a substantial improvement of seizure frequency, to drug-resistant patients with epilepsy for whom conventional resection surgery is risky or contraindicated on the basis of invasive presurgical evaluation.

[Epilepsy surgery in France]. / La chirurgie de l'épilepsie en France Evaluation de l'activité

We report here the results of the first survey on epilepsy surgery activity in France. Data from a questionnaire sent to 17 centers practicing epilepsy surgery were analyzed. All centers responded; however, all items were not completely documented. Over 50 years, more than 5000 patients have been operated on for drug-resistant epilepsy and more than 3000 patients underwent some invasive monitoring, most often SEEG. Currently, nearly 400 patients (including more than 100 children) are operated on yearly for epilepsy in France. Over a study period varying among centers (from two to 20 years; mean, 9.5 years), results from more than 2000 patients including one-third children were analyzed. Important differences between adults and children, respectively, were observed in terms of location (temporal: 72% versus 4.3%; frontal: 12% versus 28%; central: 2% versus 11%), etiology (hippocampal sclerosis: 41% versus 2%; tumors 20% versus 61%); and procedures (cortectomy: 50% versus 23%; lesionectomy: 8% versus 59%), although overall results were identical (seizure-free rates following temporal lobe surgery: 80.6% versus 79%; following extratemporal surgery: 65.9% versus 65%). In adults, the best results were observed following temporomesial (TM) resection associated with hippocampal sclerosis or other lesions (class I: 83% and 79%, respectively), temporal neocortical (TNC) lesional (82%), while resections for cryptogenic temporal resections were followed by 69% (TM) and 63% (TNC) class I outcome. Extratemporal lesional resections were associated with 71% class I outcome and cryptogenic 43%. In children, the best results were obtained in tumor-associated epilepsy regardless of location (class I: 80%). A surgical complication occurred in 8% after resective surgery - with only 2.5% permanent morbidity - and 4.3% after invasive monitoring (mostly hemorrhagic). Overall results obtained by epilepsy surgery centers were in the higher range of those reported in the literature, along with a low rate of major surgical complications. Growing interest for epilepsy surgery is clearly demonstrated in this survey and supports further development to better satisfy the population's needs, particularly children. Activity should be further evaluated, while existing epilepsy surgery centers as well as healthcare networks should be expanded.

[Epilepsy and insula]. / Epilepsie et insula.

The insula is the only cortical part of the brain that is not visible on the surface of the hemisphere, because it is totally covered by the frontoparietal and temporal opercula. The insula is triangular in shape and is separated from the opercula by the anterior, superior, and inferior peri-insular sulci. It is morphologically divided into two parts by the central insular sulcus. The anterior part of the insula bears three short gyri, and its posterior part contains two long gyri. The vascular supply of the insula is mainly provided by the M2 segment of the middle cerebral artery, a substantial obstacle to any open or stereotactic procedure aiming at the insular region. The insula is functionally involved in cardiac rhythm and arterial blood pressure control, as well as in visceromotor control and in viscerosensitive functions. There is substantial evidence that the insula is involved as a somesthetic area, including a major role in the processing of nociceptive input. The role of the insula in some epilepsies was recently investigated by means of depth electrode recordings made following Talairach's stereoelectroencephalography (SEEG) methodology. It appears that ictal signs associated with an insular discharge are very similar to those usually attributed to mesial temporal lobe seizures. Ictal symptoms associated with insular discharges are mainly made up of respiratory, viscerosensitive (chest or abdominal constriction), or oroalimentary (chewing or swallowing) manifestations. Unpleasant somatosensory manifestations, always opposite the discharging side, are also frequent. Ictal signs arising from the insula occur in full consciousness; these are always simple partial seizures. Seizures arising from the temporal lobe always invade the insular region, but in approximately 10% of cases, the seizures originate in the insular cortex itself. These data explain that there has been a rebirth of interest in the insula from a surgical perspective over the past few years. The literature contains no reports of cases of resection of insular cortex alone; most insular resections are performed in the context of temporal resection, when there is some evidence of seizures originating in the insula itself. Such procedures are risky and their efficacy, in terms of postoperative surgical outcome, has not yet been clearly assessed. In this context, less invasive procedures, such as SEEG-guided radiofrequency thermolesions of the insular cortex, are under investigation.

[Multiple SEEG-guided RF-thermolesions of epileptogenic foci]. / La thermocoagulation multiple de foyers épileptogènes guidée par la SEEG (thermo-SEEG).

In many patients with drug-resistant partial epilepsy, depth electrode recordings may be required to delineate the best region for cortical resection. We usually implant depth electrodes according to Talairach's stereoelectroencephalography (SEEG) methodology. Using these chronically-implanted depth electrodes, it is possible to generate radiofrequency (RF) thermolesions of the epileptic foci and networks. The advantages of this type of technique are supported by several lines of evidence, in particular, the high number of implanted electrodes makes it possible to generate several thermolesions, whereas the bleeding risk is null, since no additional electrode trajectory is required. Lesions are generated using 100- to 120-mA bipolar current (50V), applied for 10-40s within the epileptogenic zone, as identified by the SEEG recordings. No general or neurological complication occurred during the procedures. Forty-three patients investigated with video-SEEG recordings for presurgical assessment of drug-resistant partial epilepsy were treated using SEEG-guided RF-thermolesions of the epileptic foci between 2001 and 2006, with a follow-up ranging from 12 to 66 months. Three patients were seizure-free and 52% of the patients had a decrease in their seizure frequency of at least 50%. Of the patients presenting a malformation of cortical development etiology (i.e. dysplasia or heterotopia), 70% were classified as responders (at least a 50% decrease in seizure frequency) (p=0.052), whereas the results were less favorable in patients with a cryptogenic and hippocampal sclerosis etiology. Twenty patients underwent conventional cortectomy in a second step, 18 of whom are in Engel class I. In conclusion, SEEG-guided RF-thermolesions of the epileptic foci and networks proved to be a safe therapeutic procedure capable of providing an immediate benefit in terms of seizure control, especially in patients with epilepsy symptomatic of cortical development malformation. Such thermolesions do not preclude subsequent conventional surgery in case of failure, which can be proposed as an alternative procedure if no resective surgery is possible.

[Long-term efficiency of vagus nerve stimulation (VNS) in non-surgical refractory epilepsies in adolescents and adults]. / Efficacité de la stimulation intermittente du nerf vague dans les épilepsies pharmaco-résistantes non chirurgicales de l'adolescent et de l'adulte.

Vagus Nerve Stimulation (VNS) is recognized as an efficient procedure for controlling seizures in patients with drug-refractory epilepsies. It is used as a palliative procedure as a complement to conventional treatment by antiepileptic (AE) drugs and, according to literature, 40 to 50p.cent of patients report a decrease in seizures frequency >or=50p.cent, which is usually accepted to classify patients as responders in add on AE drug trials. The objectives of this study based on retrospective analysis of 50 consecutive patients with partial (39) or generalized (11) refractory epilepsy non eligible for surgery were; firstly to evaluate the global long term VNS efficacy and secondly to identify potential predictors of the VNS effects on seizure frequency. No patient has been seizure free at any moment of the follow up (2.8+/-1.8 years, max: 6 years) and the AE has been maintained in all. During follow up 44, 66, 61 and 58p.cent of patients were classified as responders at 6 months, 1, 2 and 3 years, respectively. Logistic regression analysis showed that: the percentage of responders at 6 months of follow up and later was significantly higher than that before 6 months (p=0.002); generalized epilepsy was predictive of a better outcome as compared to partial epilepsy (p=0.03); there was a trend for a better outcome in partial epilepsies symptomatic of a focal lesion than in those with normal brain MRI (p=0.06). These results are in line with previously published data in terms of global efficiency and confirm that seizures control does not reach its maximal level before at least one year of VNS. In severe generalized epilepsies (either secondary or cryptogenic) manifesting by frequent falls due to atonic or tonic-clonic generalized seizures VNS is a useful palliative procedure, which entails much les of surgical risk than callosotomy. The better VNS effects in patients with partial epilepsy possibly reflect the high incidence in our series of Malformations of Cortical Development, which have been identified as one the few variables possibly predictive of a response over 50p.cent of seizures frequency reduction.

Subthalamic nucleus stimulation in Parkinson's disease : anatomical and electrophysiological localization of active contacts.

OBJECTIVES: 1 - To assess the anatomical localization of the active contacts of deep brain stimulation targeted to the subthalamic nucleus (STN) in Parkinson's disease patients. 2 - To analyze the stereotactic spatial distribution of the active contacts in relation to the dorsal and the ventral electrophysiologically-defined borders of the STN and the stereotactic theoretical target. METHODS: Twenty-eight patients underwent bilateral high-frequency stimulation of the STN (HFS-STN). An indirect anatomical method based on ventriculography coupled to electrophysiological techniques were used to localize the STN. Clinical improvement was evaluated by Unified Parkinson's Disease Rating Scale motor score (UPDRS III). The normalized stereotactic coordinates of the active contact centres, dorsal and ventral electrophysiologically-defined borders of the STN were obtained from intraoperative X-rays images. These coordinates were represented in a three-dimensional stereotactic space and in the digitalized atlas of the human basal ganglia. RESULTS: HFS-STN resulted in significant improvement of motor function (62.8%) in off-medication state and levodopa-equivalent dose reduction of 68.7% (p < 0.05). Most of the active contacts (78.6%) were situated close to (+/- 1.6 mm) the dorsal border of the STN (STN-DB), while 16% were dorsal and 5.4% were ventral to it. Similar distribution was observed in the atlas. The euclidean distance between the STN-DB distribution center and the active contacts distribution center was 0.31 mm, while the distance between the active contacts distribution center and the stereotactic theoretical target was 2.15 mm. Most of the space defined by the active contacts distribution (53%) was inside that defined by the STN-DB distribution. CONCLUSION: In our series, most of the active electrodes were situated near the STN-DB. This suggests that HFS-STN could influence not only STN but also the dorsal adjacent structures (zona incerta and/or Fields of Forel).

Temporo-mesial epilepsy surgery: outcome and complications in 100 consecutive adult patients.

BACKGROUND: We studied the surgical outcome, and the complications in a group of 100 consecutive adult patients with medically refractory epilepsy arising from the temporo-mesial structures. METHODS: Hundred patients were treated surgically between 1994 and 2003 for drug-resistant epilepsy involving the temporo-mesial structures. All of them underwent a comprehensive noninvasive presurgical evaluation. Fourty-eight of them underwent depth electrodes recordings (according to the Talairach's StereoElectroEncephaloGraphic (SEEG) methodology) because the noninvasive investigations were not congruent enough to identify the epileptic zone. The patients presenting with any space-occupying lesion, or with a cavernoma, or with a strictly lateral neocortical epileptic focus, were excluded. The MRI-examination was abnormal in 87 cases, displaying a hippocampal atrophy in 69 cases. The extent of temporal resection was planned according to the results of the presurgical investigation in each particular patient. Consequently, this "tailored" resection varied from selective amygdalo-hippocampectomy (6 cases), to anterior temporal lobectomy (76 cases), or to total temporal lobectomy (18 cases). FINDINGS: The mean post-operative follow-up period was 53 months. 85 patients were found to be in Engel's class I post-operatively (free of disabling seizures), among them 74 were in class Ia (totally seizure free). Nine patients were in Engel's class II and six were in Engel's class III or IV (failures). There was no surgical mortality. Three patients had a postoperative hematoma; two patients required a shunt insertion; in three patients meningitis occurred; and two patients had postoperative ischaemia of the anterior choroidal artery territory, which resulted in a mild permanent hemiparesis. Neuropsychological complications are not addressed in detail in this article. CONCLUSIONS: These data indicate that "tailored" resective surgery for temporo-mesial epilepsy can be performed with a low rate of morbidity, and is highly efficacious. The use of invasive presurgical investigation (SEEG) may explain this high rate of success.

Hippocampal-orbitofrontal connectivity in human: an electrical stimulation study.

OBJECTIVE: The identification of the pathways involved in seizure propagation remains poorly understood in humans. For instance, the respective role of the orbitofrontal cortex (OFC) and of the commissural pathways in the interhemispheric propagation of mesial temporal lobe seizures (mTLS) is a matter of debate. In order to address this issue, we have directly tested the functional connectivity between the hippocampus and the OFC in 3 epileptic patients undergoing an intra-cranial stereotactic EEG investigation. METHODS: Bipolar electrical stimulations, consisting of two series of 25 pulses of 1 ms duration, 0.2 Hz frequency, and 3 mA intensity, were delivered in the hippocampus. Evoked potentials (EPs) were analysed for each series, separately. Grand average of reproducible EPs was then used to calculate latency of the first peak of each individual potential. RESULTS: Hippocampal stimulations evoked reproducible responses in the OFC in all 3 patients, with a mean latency of the first peak of 222 ms (range: 185-258 ms). CONCLUSIONS: Our data confirm a functional connectivity between the hippocampus and the OFC in human. SIGNIFICANCE: This connectivity supports the potential role of the OFC in the propagation of mTLS.

Intracranial EEG study of seizure-associated nose wiping.

The authors studied the relation between seizure-associated nose wiping (NW) and intracerebral EEG data in 32 patients. NW was more frequent in mesial temporal lobe seizures (TLSs; 65%) than in other TLSs (36%; p < 0.05) and in frontal lobe seizures (3%; p < 0.0001). It was associated with the presence of an amygdala discharge at seizure onset (p < 0.05) and with the recording of an ictal low-voltage fast activity within that structure (p < 0.05), supporting the role of an amygdala dysfunction in the pathophysiology of NW.

[Indications and risk of neurosurgical techniques in the adult presenting with drug-resistant partial epilepsy (radiosurgery included)]. / Indications et risques des techniques neuro-chirurgicales chez l'adulte présentant une épilepsie partielle pharmaco-résistante (radio-chirurgie comprise).

To be considered for resective (curative) surgery, most seizures have to been proved to arise exclusively from one area of the brain that is functionally silent. The drug-resistance must be certain, and the patient must be strongly motivated to undergo surgery. Temporal lobectomy for drug-resistant temporo-mesial epilepsy is now scientifically validated by a randomized controlled trial. Hemispherotomy, which consists in complete disconnection of one hemisphere, is a curative technique, which may be considered where there is a pre-existing hemiplegia associated with a structural abnormality of the contralateral hemisphere. Therefore, it is rarely performed in adult patients. Stereotactic radiosurgery is also a curative technique, which shares most of its indications with those of temporo-mesial resections. Callosotomy is a palliative technique, which consists in disconnecting the hemispheres, one from the other. It may be considered in individuals having frequent atonic seizures (drop attacks). Multiple subpial transection involves transection of transverse fibers, leaving longitudinal fibers intact. It may be performed if the epileptogenic focus is located in an eloquent brain area. The complication rate of resective surgery is low. Controlateral motor impairement is the main permanent complication related to cortical resection. It is a rare occurrence (1 to 2 percent of cases) due to peroperative lesions of the sylvian vasculature, or of the anterior choroidal artery, or even of the motor area. Postoperative hematomas, infections, or hydrocephalus may also occur in 2 to 6 percent of cases, depending on the authors. Some postoperative neuropsychological complications are reported in the literature, especially after surgery on the dominant side. Hydrocephalus and infection are the most frequent complications occurring after hemispherotomy (10 percent of cases). Dysconnexion syndrome is a rare complication, which can be seen after total callosotomy. It is unusual for the effects of disconnection after anterior callosotomy to represent significant handicap. Permanent postoperative worsening of a pre-existing neurological impairement, as well as hematomas, are seen in less than 10 percent of the cases after multiple subpial transection. In conclusion, surgery is an important therapeutic option, which has to be considered as soon as the epileptic disease appears to be drug-resistant, particularly in case of temporo-mesial epilepsy.

[Surgical treatment for epilepsy in children: indications and complications]. / Indications et risques des techniques neuro-chirurgicales chez l'enfant présentant une épilepsie partielle pharmaco-résistante.

The main etiologies of epilepsy are somewhat different in the pediatric population, from those found in the adults. This explains why temporal resections are less frequently performed in children than in adults. To be considered for resective (curative) surgery, most seizures have to been proved to arise exclusively from one area of the brain that is functionally silent. The drug-resistance must be certain, and the patient, or his family, must be strongly motivated to undergo surgery. Hemispherotomy, which consists in complete disconnection of one hemisphere, is a curative technique, which may be considered where there is a pre-existing hemiplegia associated with a structural abnormality of the contralateral hemisphere. Callosotomy is a palliative technique, which consists in disconnecting the hemispheres, one from the other. It may be considered in individuals having frequent atonic seizures (drop attacks). Multiple subpial transection involves transection of transverse fibers, leaving longitudinal fibers intact. It may be performed if the epileptogenic focus is located in an eloquent brain area. It may also be performed in case of Landau-Kleffner syndrome. The complication rate of resective surgery is low. Contralateral motor impairement is the main permanent complication related to cortical resection. It is a rare occurrence (1 to 2 percent of cases) due to peroperative lesions of the sylvian vasculature, or of the anterior choroidal artery, or even of the motor area. Postoperative hematomas, infections, or hydrocephalus may also occur in 2 to 6 percent of cases, depending on the authors. Some postoperative neuropsychological complications are reported in the literature, especially after surgery on the dominant side. Hydrocephalus and infection are the most frequent complications occurring after hemispherotomy (10 percent of cases). Dysconnexion syndrome is a rare complication, which can be seen after total callosotomy. It is unusual for the effects of disconnection after anterior callosotomy to represent significant handicap. Permanent postoperative worsening of a pre-existing neurological impairement is seen in less than 10 percent of the cases after multiple subpial transection. In conclusion, surgery has to be considered without unnecessary delay in the children presenting with drug-resistant epilepsy, before any cognitive or psychosocial deterioration, due to the epileptic disease, occurs.

[Surgical treatment of epilepsy: outcome of various surgical procedures in adults and children]. / Evaluation des résultats de la chirurgie de l'épilepsie.

Surgical treatment of drug-resistant epilepsy is being performed in a growing number of adults and children. The objective of this report is to review and evaluate the published literature related to the outcome of epilepsy surgery. Surgical procedures were classified as "curative", which included temporal and extratemporal resections, as well as hemispherotomy and stereotactic radiosurgery, and as "palliative", which mainly included callosotomy and multiple subpial transections. Data obtained from the literature suggest that after temporal lobe surgery, 68 percent of the adult patients, on average, are seizure-free. This result may vary, according to the authors, from 50 to 93 percent. One randomized controlled study concludes that 58 percent of patients treated surgically become seizure-free, compared to only 8 percent in the group of patients who do not receive surgery. This suggests that temporal lobe surgery is an efficient treatment of drug-refractory temporal lobe surgery. Seizure outcome is similar in the pediatric population. Studies of frontal lobe surgery report that an average of 60 percent of patients are seizure-free after surgery, in adults as well as in children. These results may vary considerably, depending on how the seizure outcome is defined. Too few studies are available to allow for an evaluation of parietal or occipital lobe surgery. Hemispherotomy is mostly performed in the pediatric population. Studies of this procedure report that 60 percent of patients become seizure free after surgery, whereas 80 percent are improved in terms of seizure outcome and in terms of behavior. Stereotactic radiosurgery may be performed in case of hypothalamic hamartoma, and in some cases of temporal lobe epilepsy. In this later case, the reported results are similar to those obtained with temporal resections. Seizure outcome after corpus callosotomy is difficult to summarize, because of the many variations, according to the authors, of the definition of a good or poor seizure outcome. However, it can be stated that 65 to 85 percent of patients achieve a significant reduction in overall seizure frequency. The best reduction in seizure frequency is achieved in patients with atonic. Reported percentages of patients who benefit from multiple subpial transection, varies between 50 and 70 percent. In conclusion, our report shows that temporal resection is an efficient and scientifically validated treatment of drug-resistant temporal lobe epilepsy. Extra-temporal resections, hemispherotomy, and palliative surgery often allow cure of epilepsy, or a decrease of seizure frequency, however, prospective studies of these surgical procedures are needed.

Surgical anatomy of the insula.

The insula is the only cortical part of the brain which is not visible on the surface of the hemisphere. This is due to the fact that it is totally covered by the fronto-parietal and temporal opercula. The insula has a triangular shape, and is separated from the opercula by the anterior, superior, and inferior periinsular sulci. The limen insulae is the antero-inferiorly located insular cortical surface which conjoins the inferior insular point, the anterior perforated surface, and the temporo-mesial surface. The insula is morphologically divided into two parts by the central insular sulcus. The anterior part of the insula bears 3 gyri: the anterior, middle, and posterior short insular gyri, separated by the anterior and precentral insular sulcus. The posterior part of the insula contains the anterior and posterior long insular gyri, separated by the postcentral insular sulcus. The vascular supply of the insula is mainly provided by the M2 segment of the middle cerebral artery, which constitutes a substantial obstacle to any open or stereotactic procedure aiming at the insular region. Histologically, the insula is a part of the paralimbic cortex, as it bears in its antero-inferior part an allo and mesocortical area. The insula is functionally involved in cardiac rhythm and arterial blood pressure control, as well as in viscero-motor control and in viscero-sensitive functions. There is considerable evidence for the involvement of the insula as a somesthetic area, including a major role in the processing of nociceptive inputs. Its possible role in some epilepsies may explain some failures of temporal lobe resection. Surgery of the insular lobe is a technical challenge, whose risks can be minimized by the use of intra-operative direct cerebral stimulation.