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1.
Epilepsy Behav ; 149: 109509, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37935078

RESUMO

Several studies have shown that the retroinsular and posterior parietal operculum regions play a central role in vestibular processing. Electrical stimulations performed during stereoelectroencephalography (SEEG) in patients with focal drug-resistant epilepsy could contribute to the analysis of this area. Among the 264 SEEGs performed in both an adult and a paediatric epilepsy surgery centre, we retrospectively identified 24 patients (9%) reporting vertigo during electrical stimulations (ES). In seven of them (29% of patients experiencing vertigo during ES), it was evoked by stimulating the retroinsular region. The reported responses were mostly not rotatory sensations but actually illusions of body, limb or limb segment movement. The involved area is limited. Moreover, two patients reported having the same symptoms at the beginning of their seizures starting in the same region. Our case study confirms the pivotal role of the retroinsular and posterior parietal operculum areas in vestibular responses, and we therefore advise the exploration of this region when patients report an illusion of body movement at the beginning of their seizures.


Assuntos
Epilepsia , Neocórtex , Adulto , Criança , Humanos , Córtex Cerebral/fisiologia , Estudos Retrospectivos , Convulsões , Epilepsia/diagnóstico por imagem , Técnicas Estereotáxicas , Vertigem , Eletroencefalografia
2.
Hum Brain Mapp ; 43(15): 4580-4588, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35703584

RESUMO

Focal seizures originating from the temporal lobe are commonly associated with peri-ictal 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 indices obtained during SEEG (stereoencephalography) recordings in 38 patients, we evaluated the epileptogenicity, the spatial propagation, and functional connectivity between those structures during seizures leading to PIH. Multivariate statistical analyses of SEEG quantitative indices showed that temporal lobe seizures leading to PIH are characterized by a strong involvement of amygdala and anterior insula during seizure propagation and a more widespread involvement of medial temporal lobe structures, lateral temporal lobe, temporal pole, and anterior cingulate at the end of the seizures. On the contrary, seizure-onset zone was not associated with PIH occurrence. During seizure propagation, anterior insula, temporal pole, and temporal lateral neocortex activities were correlated with intensity of PIH. Lastly, PIH occurrence was also related to a widespread increase of synchrony between those structures. Those results suggest that PIH occurrence during temporal lobe seizures may be related to the activation of a widespread network of cortical structures, among which amygdala and anterior insula are key nodes.


Assuntos
Eletroencefalografia , Epilepsia do Lobo Temporal , Eletroencefalografia/métodos , Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/diagnóstico por imagem , Humanos , Hipóxia/diagnóstico por imagem , Convulsões/complicações , Convulsões/diagnóstico por imagem , Lobo Temporal/diagnóstico por imagem
3.
Epilepsia ; 63(4): 769-776, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35165888

RESUMO

OBJECTIVE: Temporal plus epilepsy (TPE) represents a rare type of epilepsy characterized by a complex epileptogenic zone including the temporal lobe and the close neighboring structures. We investigated whether the complete resection of temporal plus epileptogenic zone as defined through stereoelectroencephalography (SEEG) might improve seizure outcome in 38 patients with TPE. METHODS: Inclusion criteria were as follows: epilepsy surgery performed between January 1990 and December 2001, SEEG defining a temporal plus epileptogenic zone, unilobar temporal operations ("temporal lobe epilepsy [TLE] surgery") or multilobar interventions including the temporal lobe ("TPE surgery"), magnetic resonance imaging either normal or showing signs of hippocampal sclerosis, and postoperative follow-up of at least 12 months. For each assessment of postoperative seizure outcome, at 1, 2, 5, and 10 years, we carried out descriptive analysis and classical tests of hypothesis, namely, Pearson χ2 test or Fisher exact test of independence on tables of frequency for each categorical variable of interest and Student t-test for each continuous variable of interest, when appropriate. RESULTS: Twenty-one patients underwent TPE surgery and 17 underwent TLE surgery with a follow-up of 12.4 ± 8.16 years. In the multivariate models, there was a significant effect of the time from surgery on Engel Class IA versus IB-IV outcome, with a steadily worsening trend from 5-year follow-up onward. TPE surgery was associated with better results than TLE surgery. SIGNIFICANCE: This study suggests that surgical outcome in patients with TPE can be improved by a tailored, multilobar resection and confirms that SEEG is mandatory when a TPE is suspected.


Assuntos
Epilepsia do Lobo Temporal , Epilepsia , Eletroencefalografia/métodos , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/cirurgia , Humanos , Estudos Retrospectivos , Convulsões , Resultado do Tratamento
4.
Epilepsia ; 63(9): 2359-2370, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35775943

RESUMO

OBJECTIVE: Epileptic spasms (ES) are common in tuberous sclerosis complex (TSC). However, the underlying network alterations and relationship with epileptogenic tubers are poorly understood. We examined interictal functional connectivity (FC) using stereo-electroencephalography (SEEG) in patients with TSC to investigate the relationship between tubers, epileptogenicity, and ES. METHODS: We analyzed 18 patients with TSC who underwent SEEG (mean age = 11.5 years). The dominant tuber (DT) was defined as the most epileptogenic tuber using the epileptogenicity index. Epileptogenic zone (EZ) organization was quantitatively separated into focal (isolated DT) and complex (all other patterns). Using a 20-min interictal recording, FC was estimated with nonlinear regression, h2 . We calculated (1) intrazone FC within all sampled tubers and normal-appearing cortical zones, respectively; and (2) interzone FC involving connections between DT, other tubers, and normal cortex. The relationship between FC and (1) presence of ES as a current seizure type at the time of SEEG, (2) EZ organization, and (3) epileptogenicity was analyzed using a mixed generalized linear model. Spike rate and distance between zones were considered in the model as covariates. RESULTS: Six patients had ES as a current seizure type at time of SEEG. ES patients had a greater number of tubers with a fluid-attenuated inversion recovery hypointense center (p < .001), and none had TSC1 mutations. The presence of ES was independently associated with increased FC within both intrazone (p = .033) and interzone (p = .011) networks. Post hoc analyses identified that increased FC was associated with ES across tuber and nontuber networks. EZ organization and epileptogenicity biomarkers were not associated with FC. SIGNIFICANCE: Increased cortical synchrony among both tuber and nontuber networks is characteristic of patients with ES and independent of both EZ organization and tuber epileptogenicity. This further supports the prospect of FC biomarkers aiding treatment paradigms in TSC.


Assuntos
Epilepsia , Espasmos Infantis , Esclerose Tuberosa , Criança , Humanos , Eletroencefalografia , Imageamento por Ressonância Magnética , Convulsões/complicações , Espasmo , Espasmos Infantis/complicações , Esclerose Tuberosa/genética
5.
BMC Neurol ; 21(1): 363, 2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34537017

RESUMO

BACKGROUND: When MRI fails to detect a potentially epileptogenic lesion, the chance of a favorable outcome after epilepsy surgery becomes significantly lower (from 60 to 90% to 20-65%). Hybrid FDG-PET/MRI may provide additional information for identifying the epileptogenic zone. We aimed to investigate the possible effect of the introduction of hybrid FDG-PET/MRI into the algorithm of the decision-making in both lesional and non-lesional drug-resistant epileptic patients. METHODS: In a prospective study of patients suffering from drug-resistant focal epilepsy, 30 nonlesional and 30 lesional cases with discordant presurgical results were evaluated using hybrid FDG-PET/MRI. RESULTS: The hybrid imaging revealed morphological lesion in 18 patients and glucose hypometabolism in 29 patients within the nonlesional group. In the MRI positive group, 4 patients were found to be nonlesional, and in 9 patients at least one more epileptogenic lesion was discovered, while in another 17 cases the original lesion was confirmed by means of hybrid FDG-PET/MRI. As to the therapeutic decision-making, these results helped to indicate resective surgery instead of intracranial EEG (iEEG) monitoring in 2 cases, to avoid any further invasive diagnostic procedures in 7 patients, and to refer 21 patients for iEEG in the nonlesional group. Hybrid FDG-PET/MRI has also significantly changed the original therapeutic plans in the lesional group. Prior to the hybrid imaging, a resective surgery was considered in 3 patients, and iEEG was planned in 27 patients. However, 3 patients became eligible for resective surgery, 6 patients proved to be inoperable instead of iEEG, and 18 cases remained candidates for iEEG due to the hybrid FDG-PET/MRI. Two patients remained candidates for resective surgery and one patient became not eligible for any further invasive intervention. CONCLUSIONS: The results of hybrid FDG-PET/MRI significantly altered the original plans in 19 of 60 cases. The introduction of hybrid FDG-PET/MRI into the presurgical evaluation process had a potential modifying effect on clinical decision-making. TRIAL REGISTRATION: Trial registry: Scientific Research Ethics Committee of the Medical Research Council of Hungary. TRIAL REGISTRATION NUMBER: 008899/2016/OTIG . Date of registration: 08 February 2016.


Assuntos
Epilepsia , Preparações Farmacêuticas , Eletroencefalografia , Fluordesoxiglucose F18 , Humanos , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Estudos Prospectivos
6.
Epilepsy Behav ; 122: 108125, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34144458

RESUMO

OBJECTIVE: Electrical stimulations performed in awake patients identified dura mater, venous sinuses, and arteries as pain-sensitive intracranial structures. However, cephalic pain has been only occasionally reported in patients with epilepsy undergoing stereo-electroencephalography (SEEG) stimulations. METHODS: The aim of our study was to investigate whether headache can be triggered by SEEG stimulations and might be related to specific cortical areas. Data were gathered from 16 050 stimulations collected in 266 patients who underwent a SEEG as part of a presurgical assessment of their drug-resistant epilepsy. RESULTS: Two-hundred and eight stimulations (1.3%) evoked headaches. Pain was more frequently described as bilateral (42.31%) than ipsilateral (16.83%) or contralateral (14.42%) to the stimulated hemisphere. Headache was more frequently elicited during stimulation of the insulo-limbic regions such as the anterior and medial cingulate gyrus, the mesial part of temporal lobe, and the insula. CONCLUSION: This study shows that cortical stimulation can evoke headache, mostly during stimulation of the temporo-frontal limbic regions. It suggests that brief epileptic headache can be an epileptic symptom caused by a cortical discharge involving somatic or visceral network and does not reflect only trigemino-vascular activation. Although not specific, the occurrence of a brief epileptic headache may point to a seizure origin in the temporo-frontal limbic regions.


Assuntos
Epilepsias Parciais , Estimulação Elétrica , Eletroencefalografia , Epilepsias Parciais/complicações , Cefaleia/etiologia , Humanos , Convulsões , Lobo Temporal
7.
Epilepsia ; 61(1): 81-95, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31860139

RESUMO

OBJECTIVE: In tuberous sclerosis complex (TSC)-associated drug-resistant epilepsy, the optimal invasive electroencephalographic (EEG) and operative approach remains unclear. We examined the role of stereo-EEG in TSC and used stereo-EEG data to investigate tuber and surrounding cortex epileptogenicity. METHODS: We analyzed 18 patients with TSC who underwent stereo-EEG (seven adults). One hundred ten seizures were analyzed with the epileptogenicity index (EI). In 13 patients with adequate tuber sampling, five anatomical regions of interest (ROIs) were defined: dominant tuber (tuber with highest median EI), perituber cortex, secondary tuber (tuber with second highest median EI), nearby cortex (normal-appearing cortex in the same lobe as dominant tuber), and distant cortex (in other lobes). At the seizure level, epileptogenicity of ROIs was examined by comparing the highest EI recorded within each anatomical region. At the patient level, epileptogenic zone (EZ) organization was separated into focal tuber (EZ confined to dominant tuber) and complex (all other patterns). RESULTS: The most epileptogenic ROI was the dominant tuber, with higher EI than perituber cortex, secondary tuber, nearby cortex, and distant cortex (P < .001). A focal tuber EZ organization was identified in seven patients. This group had 80% Engel IA postsurgical outcome and distinct dominant tuber characteristics: continuous interictal discharges (IEDs; 100%), fluid-attenuated inversion recovery (FLAIR) hypointense center (86%), center-to-rim EI gradient, and stimulation-induced seizures (71%). In contrast, six patients had a complex EZ organization, characterized by nearby cortex as the most epileptogenic region and 40% Engel IA outcome. At the intratuber level, the combination of FLAIR hypointense center, continuous IEDs, and stimulation-induced seizures offered 98% specificity for a focal tuber EZ organization. SIGNIFICANCE: Tubers with focal EZ organization have a striking similarity to type II focal cortical dysplasia. The presence of distinct EZ organizations has significant implications for EZ hypothesis generation, invasive EEG approach, and resection strategy.


Assuntos
Epilepsia Resistente a Medicamentos/fisiopatologia , Eletroencefalografia/métodos , Esclerose Tuberosa/fisiopatologia , Adulto , Criança , Pré-Escolar , Epilepsia Resistente a Medicamentos/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Esclerose Tuberosa/complicações
8.
Hum Brain Mapp ; 40(9): 2611-2622, 2019 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-30815964

RESUMO

Despite numerous studies suggesting the role of insular cortex in the control of autonomic activity, the exact location of cardiac motor regions remains controversial. We provide here a functional mapping of autonomic cardiac responses to intracortical stimulations of the human insula. The cardiac effects of 100 insular electrical stimulations into 47 epileptic patients were divided into tachycardia, bradycardia, and no cardiac response according to the magnitude of RR interval (RRI) reactivity. Sympathetic (low frequency, LF, and low to high frequency powers ratio, LF/HF ratio) and parasympathetic (high frequency power, HF) reactivity were studied using RRI analysis. Bradycardia was induced by 26 stimulations (26%) and tachycardia by 21 stimulations (21%). Right and left insular stimulations induced as often a bradycardia as a tachycardia. Tachycardia was accompanied by an increase in LF/HF ratio, suggesting an increase in sympathetic tone; while bradycardia seemed accompanied by an increase of parasympathetic tone reflected by an increase in HF. There was some left/right asymmetry in insular subregions where increased or decreased heart rates were produced after stimulation. However, spatial distribution of tachycardia responses predominated in the posterior insula, whereas bradycardia sites were more anterior in the median part of the insula. These findings seemed to indicate a posterior predominance of sympathetic control in the insula, whichever the side; whereas the parasympathetic control seemed more anterior. Dysfunction of these regions should be considered when modifications of cardiac activity occur during epileptic seizures and in cardiovascular diseases.


Assuntos
Bradicardia/fisiopatologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiologia , Eletrocorticografia , Frequência Cardíaca/fisiologia , Sistema Nervoso Parassimpático/fisiologia , Sistema Nervoso Simpático/fisiologia , Taquicardia/fisiopatologia , Adulto , Estimulação Elétrica , Eletrocardiografia , Epilepsia/cirurgia , Feminino , Humanos , Masculino
9.
Ann Neurol ; 82(3): 360-370, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28796326

RESUMO

OBJECTIVE: Despite numerous studies suggesting the role of insular cortex in the processing of gustatory and olfactory inputs, the exact location of olfactogustatory representation in the insula remains controversial. Here we provide a functional mapping of olfactory-gustatory responses to stimulation of the human insular cortex. METHODS: We reviewed 651 electrical stimulations of the insula that were performed in 221 patients, using stereotactically implanted depth electrodes, during the presurgical evaluation of drug-refractory epilepsy. RESULTS: Gustatory sensations were evoked in 15 (2.7%) of the 550 stimulations that elicited a clinical response. They were exclusively obtained after stimulation of a relatively delimited zone of insula, located in its mid-dorsal part (posterior short gyrus). Six olfactory sensations (1.1%) could be obtained during stimulations of an insular region that partially overlapped with the gustatory representation. INTERPRETATION: Our study provides a functional mapping of gustatory representation in the insular posterior short gyrus and the first detailed description of olfactory sensations obtained by direct stimulation of mid-dorsal insula. Our data also show a spatial overlap between gustatory, olfactory, and oral somatosensory representation in the mid-dorsal insula, and suggest that this part of the insula may be an integrated oral sensory region that plays a key role in flavor perception. It also indicates that dysfunction in this region should be considered during the evaluation of gustatory and olfactory epileptic seizures. Ann Neurol 2017;82:360-370.


Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiopatologia , Paladar/fisiologia , Adulto , Epilepsia Resistente a Medicamentos/fisiopatologia , Epilepsia Resistente a Medicamentos/cirurgia , Estimulação Elétrica , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Adulto Jovem
10.
Epilepsia ; 59(12): 2296-2304, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30345535

RESUMO

OBJECTIVE: Despite the increasing number of studies reporting results of stereo-electroencephalography (SEEG)-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC) in the treatment of patients with drug-resistant focal epilepsy, the exact efficacy of this approach remains unclear. The seizure-freedom rate varies greatly across studies and the factors associated with efficacy have not been formally investigated. METHODS: All prospective or retrospective studies reporting efficacy and/or safety of SEEG-guided RF-TC in patients with drug-resistant focal epilepsy were included. The primary outcome was the seizure-free rate 1 year after the procedure. Secondary outcomes were (1) the responder rate 1 year after the procedure and (2) the proportion of patients with permanent neurologic deficit 1 year after the procedure. Each outcome was assessed in all patients and in 4 groups of patients defined by the etiology of epilepsy. Each outcome was pooled using inverse variance weighting, logit transformation of proportion, and a random-effects model. RESULTS: No prospective study was identified and a total of 6 retrospective studies, reporting efficacy and safety data of 296 patients, were included. The pooled rate of permanent neurologic deficit was 2.5% (95% confidence interval [CI] 1.2%-5.3%), without heterogeneity across studies. In contrast, both the seizure-free and responder rates varied greatly across studies, and statistical heterogeneity was high. The pooled seizure-free and responder rates were 23% (95% CI 8%-50%) and 58% (95% CI 36%-77%), respectively. Both for the seizure-free and responder rates, the greatest efficacy was observed in patients with periventricular nodular heterotopia and the lowest in patients with normal magnetic resonance imaging (MRI) findings. SIGNIFICANCE: SEEG-guided RF-TC is a safe procedure with low risk of complications. In contrast, the level of evidence regarding its efficacy remains low. Better identification of factors associated with seizure outcome are needed.


Assuntos
Eletrocoagulação/métodos , Eletroencefalografia/métodos , Epilepsias Parciais/cirurgia , Procedimentos Neurocirúrgicos/métodos , Cirurgia Assistida por Computador/métodos , Eletrocoagulação/efeitos adversos , Humanos , Procedimentos Neurocirúrgicos/efeitos adversos , Cirurgia Assistida por Computador/efeitos adversos , Resultado do Tratamento
11.
Epilepsy Behav ; 85: 76-84, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29909256

RESUMO

OBJECTIVE: Few data are available about the functionality of type II focal cortical dysplasia (FCD). Identification of high-frequency activities (HFAs) induced by cognitive tasks has been proposed as an additional way to map cognitive functions in patients undergoing presurgical evaluation using stereoelectroencephalography (SEEG). However, the repetitive subcontinuous spiking pattern which characterizes type II FCD might limit the reliability of this approach, and its feasibility in these patients remains to be evaluated. METHODS: Seven patients whose magnetic resonance imaging (MRI) data, SEEG data, and/or pathological data were consistent with the diagnosis of type II FCD were included. All patients performed standardized cognitive tasks specifically designed to map task-induced increase of HFA (50 Hz to 150 Hz) at the recorded sites. Electrode contacts which showed an interictal SEEG pattern typical of type II FCD were considered to be localized within the FCD. A site was considered responsive if it was significantly different from baseline in at least one cognitive task. RESULTS: Three of the seven patients (43%) had significant task-induced increase of HFA in the FCD for a total of 15 sites with an interictal SEEG pattern typical of type II FCD. These sites were always localized at the external border of the FCD whereas no HFA response was in the core of FCD. In three of the four other patients, a significant task-induced increase of HFA was observed in a cortical site immediately adjacent to the dysplastic cortex. SIGNIFICANCE: Detection of task-induced HFA remains feasible despite the repetitive subcontinuous spiking pattern which characterizes type II FCD. Depending on the localization of the FCD, some sites of the dysplastic cortex were included in large-scale functional networks. However, these sites were always those closest to the nondysplastic cortex suggesting that persistence of cortical functions might be restricted to a limited part of the FCD.


Assuntos
Epilepsia/diagnóstico por imagem , Epilepsia/fisiopatologia , Ritmo Gama/fisiologia , Malformações do Desenvolvimento Cortical do Grupo I/diagnóstico por imagem , Malformações do Desenvolvimento Cortical do Grupo I/fisiopatologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Adulto , Eletroencefalografia/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Técnicas Estereotáxicas
12.
Epilepsia ; 58(1): 85-93, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27859033

RESUMO

OBJECTIVE: Stereo electroencephalography (SEEG)-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) has been proposed since 2004 as a possible treatment of some focal drug-resistant epilepsy. The aim of this study is to provide extensive data about efficacy and safety of SEEG-guided RF-TC. METHODS: Over a 10-year period, 162 patients with drug-resistant focal epilepsy were eligible for SEEG-guided RF-TG during phase II invasive investigation by SEEG. All follow-up and safety data were collected prospectively. The primary outcome was seizure freedom at 2 months and at 1 year after SEEG-guided RF-TC. Secondary outcomes were the responders' rate (patient with at least 50% decrease in seizure frequency) and their long-term follow-up. RESULTS: Twenty-five percent of patients were seizure-free at 2 months and 7% at 1 year. We reported 67% of responders at 2 months and 48% at 1 year; 58% of responders maintained their status during the long-term follow-up. The seizure outcome was significantly better when the SEEG-guided RF-TC involved the occipital region (p = 0.007). When surgery followed an SEEG-guided RF-TC, the positive predictive value of being a responder 2 months after an SEEG-guided RF-TC and to be Engel's class I or II after surgery was 93%. We reported 1.1% of permanent deficit and 2.4% of transient side effects. SIGNIFICANCE: Our results, gathered in a large population over a 10-year period, confirm that SEEG-guided RF-TC is a safe technique, being efficient in many cases. More than two thirds of patients showed a short-term improvement, and almost half of them were responders at 1-year follow-up. The technique appears to be especially interesting for limited epileptic zone inaccessible to surgery and when epilepsy is related to a large unilateral network (network disruption by multiple RF-TC). Furthermore, SEEG-guided RF-TC effect is a predictor of outcome after conventional cortectomy in patients eligible for surgery.


Assuntos
Epilepsia Resistente a Medicamentos/terapia , Eletrocoagulação/métodos , Eletroencefalografia , Epilepsias Parciais/terapia , Técnicas Estereotáxicas , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Epilepsias Parciais/diagnóstico por imagem , Feminino , Humanos , Estimativa de Kaplan-Meier , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Neuroimagem , Resultado do Tratamento , Adulto Jovem
13.
Brain ; 139(Pt 4): 1295-309, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26811252

RESUMO

The orbitofrontal cortex is known to carry information regarding expected reward, risk and experienced outcome. Yet, due to inherent limitations in lesion and neuroimaging methods, the neural dynamics of these computations has remained elusive in humans. Here, taking advantage of the high temporal definition of intracranial recordings, we characterize the neurophysiological signatures of the intact orbitofrontal cortex in processing information relevant for risky decisions. Local field potentials were recorded from the intact orbitofrontal cortex of patients suffering from drug-refractory partial epilepsy with implanted depth electrodes as they performed a probabilistic reward learning task that required them to associate visual cues with distinct reward probabilities. We observed three successive signals: (i) around 400 ms after cue presentation, the amplitudes of the local field potentials increased with reward probability; (ii) a risk signal emerged during the late phase of reward anticipation and during the outcome phase; and (iii) an experienced value signal appeared at the time of reward delivery. Both the medial and lateral orbitofrontal cortex encoded risk and reward probability while the lateral orbitofrontal cortex played a dominant role in coding experienced value. The present study provides the first evidence from intracranial recordings that the human orbitofrontal cortex codes reward risk both during late reward anticipation and during the outcome phase at a time scale of milliseconds. Our findings offer insights into the rapid mechanisms underlying the ability to learn structural relationships from the environment.


Assuntos
Sinais (Psicologia) , Córtex Pré-Frontal/fisiologia , Recompensa , Adulto , Eletrodos Implantados , Eletroencefalografia/métodos , Epilepsias Parciais/diagnóstico , Epilepsias Parciais/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Fatores de Risco , Adulto Jovem
14.
Brain ; 139(Pt 2): 444-51, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26700686

RESUMO

Reasons for failed temporal lobe epilepsy surgery remain unclear. Temporal plus epilepsy, characterized by a primary temporal lobe epileptogenic zone extending to neighboured regions, might account for a yet unknown proportion of these failures. In this study all patients from two epilepsy surgery programmes who fulfilled the following criteria were included: (i) operated from an anterior temporal lobectomy or disconnection between January 1990 and December 2001; (ii) magnetic resonance imaging normal or showing signs of hippocampal sclerosis; and (iii) postoperative follow-up ≥ 24 months for seizure-free patients. Patients were classified as suffering from unilateral temporal lobe epilepsy, bitemporal epilepsy or temporal plus epilepsy based on available presurgical data. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom over time. Predictors of seizure recurrence were investigated using Cox proportional hazards model. Of 168 patients included, 108 (63.7%) underwent stereoelectroencephalography, 131 (78%) had hippocampal sclerosis, 149 suffered from unilateral temporal lobe epilepsy (88.7%), one from bitemporal epilepsy (0.6%) and 18 (10.7%) from temporal plus epilepsy. The probability of Engel class I outcome at 10 years of follow-up was 67.3% (95% CI: 63.4-71.2) for the entire cohort, 74.5% (95% CI: 70.6-78.4) for unilateral temporal lobe epilepsy, and 14.8% (95% CI: 5.9-23.7) for temporal plus epilepsy. Multivariate analyses demonstrated four predictors of seizure relapse: temporal plus epilepsy (P < 0.001), postoperative hippocampal remnant (P = 0.001), past history of traumatic or infectious brain insult (P = 0.022), and secondary generalized tonic-clonic seizures (P = 0.023). Risk of temporal lobe surgery failure was 5.06 (95% CI: 2.36-10.382) greater in patients with temporal plus epilepsy than in those with unilateral temporal lobe epilepsy. Temporal plus epilepsy represents a hitherto unrecognized prominent cause of temporal lobe surgery failures. In patients with temporal plus epilepsy, anterior temporal lobectomy appears very unlikely to control seizures and should not be advised. Whether larger resection of temporal plus epileptogenic zones offers greater chance of seizure freedom remains to be investigated.


Assuntos
Lobectomia Temporal Anterior/tendências , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/cirurgia , Lobo Temporal/cirurgia , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Temporal/patologia , Falha de Tratamento , Resultado do Tratamento , Adulto Jovem
15.
Ann Neurol ; 76(4): 609-19, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25142204

RESUMO

OBJECTIVE: The present study provides a functional mapping of vestibular responses in the human insular cortex. METHODS: A total of 642 electrical stimulations of the insula were performed in 219 patients, using stereotactically implanted depth electrodes, during the presurgical evaluation of drug-refractory partial epilepsy. We retrospectively identified 41 contacts where stimulation elicited vestibular sensations (VSs) and analyzed their location with respect to (1) their stereotactic coordinates (for all contacts), (2) the anatomy of insula gyri (for 20 vestibular sites), and (3) the probabilistic cytoarchitectonic maps of the insula (for 9 vestibular sites). RESULTS: VSs occurred in 7.6% of the 541 evoked sensations after electrical stimulations of the insula. VSs were mostly obtained after stimulation of the posterior insula, that is, in the granular insular cortex and the postcentral insular gyrus. The data also suggest a spatial segregation of the responses in the insula, with the rotatory and translational VSs being evoked at more posterior stimulation sites than other less definable VSs. No left-right differences were observed. INTERPRETATION: These results demonstrate vestibular sensory processing in the insula that is centered on its posterior part. The present data add to the understanding of the multiple sensory functions of the insular cortex and of the cortical processing of vestibular signals. The data also indicate that lesion or dysfunction in the posterior insula should be considered during the evaluation of vestibular epileptic seizures.


Assuntos
Córtex Cerebral/fisiologia , Estimulação Elétrica , Potenciais Evocados Auditivos/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/anatomia & histologia , Eletrodos Implantados , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
16.
Brain ; 136(Pt 10): 3176-86, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24014520

RESUMO

Surgical treatment of epilepsy is a challenge for patients with non-contributive brain magnetic resonance imaging. However, surgery is feasible if the seizure-onset zone is precisely delineated through intracranial electroencephalography recording. We recently described a method, volumetric imaging of epileptic spikes, to delineate the spiking volume of patients with focal epilepsy using magnetoencephalography. We postulated that the extent of the spiking volume delineated with volumetric imaging of epileptic spikes could predict the localizability of the seizure-onset zone by intracranial electroencephalography investigation and outcome of surgical treatment. Twenty-one patients with non-contributive magnetic resonance imaging findings were included. All patients underwent intracerebral electroencephalography investigation through stereotactically implanted depth electrodes (stereo-electroencephalography) and magnetoencephalography with delineation of the spiking volume using volumetric imaging of epileptic spikes. We evaluated the spatial congruence between the spiking volume determined by magnetoencephalography and the localization of the seizure-onset zone determined by stereo-electroencephalography. We also evaluated the outcome of stereo-electroencephalography and surgical treatment according to the extent of the spiking volume (focal, lateralized but non-focal or non-lateralized). For all patients, we found a spatial overlap between the seizure-onset zone and the spiking volume. For patients with a focal spiking volume, the seizure-onset zone defined by stereo-electroencephalography was clearly localized in all cases and most patients (6/7, 86%) had a good surgical outcome. Conversely, stereo-electroencephalography failed to delineate a seizure-onset zone in 57% of patients with a lateralized spiking volume, and in the two patients with bilateral spiking volume. Four of the 12 patients with non-focal spiking volumes were operated upon, none became seizure-free. As a whole, patients having focal magnetoencephalography results with volumetric imaging of epileptic spikes are good surgical candidates and the implantation strategy should incorporate volumetric imaging of epileptic spikes results. On the contrary, patients with non-focal magnetoencephalography results are less likely to have a localized seizure-onset zone and stereo electroencephalography is not advised unless clear localizing information is provided by other presurgical investigation methods.


Assuntos
Mapeamento Encefálico , Epilepsias Parciais/cirurgia , Magnetoencefalografia , Convulsões/cirurgia , Adolescente , Adulto , Criança , Pré-Escolar , Eletrodos Implantados , Epilepsias Parciais/diagnóstico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Magnetoencefalografia/métodos , Masculino , Pessoa de Meia-Idade , Convulsões/diagnóstico , Resultado do Tratamento , Adulto Jovem
17.
Cereb Cortex ; 23(10): 2437-47, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22875860

RESUMO

The feeling of being excluded from a social interaction triggers social pain, a sensation as intense as actual physical pain. Little is known about the neurophysiological underpinnings of social pain. We addressed this issue using intracranial electroencephalography in 15 patients performing a ball game where inclusion and exclusion blocks were alternated. Time-frequency analyses showed an increase in power of theta-band oscillations during exclusion in the anterior insula (AI) and posterior insula, the subgenual anterior cingulate cortex (sACC), and the fusiform "face area" (FFA). Interestingly, the AI showed an initial fast response to exclusion but the signal rapidly faded out. Activity in the sACC gradually increased and remained significant thereafter. This suggests that the AI may signal social pain by detecting emotional distress caused by the exclusion, whereas the sACC may be linked to the learning aspects of social pain. Theta activity in the FFA was time-locked to the observation of a player poised to exclude the participant, suggesting that the FFA encodes the social value of faces. Taken together, our findings suggest that theta activity represents the neural signature of social pain. The time course of this signal varies across regions important for processing emotional features linked to social information.


Assuntos
Encéfalo/fisiologia , Giro do Cíngulo/fisiologia , Percepção da Dor/fisiologia , Distância Psicológica , Ritmo Teta , Adulto , Eletroencefalografia , Sincronização de Fases em Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
18.
Epilepsia ; 54(2): 296-304, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22988886

RESUMO

PURPOSE: To define the relationship between the epileptogenic zone and the polymicrogyric area using intracranial electroencephalography (EEG) recordings in patients with structural epilepsy associated with regional infrasylvian polymicrogyria (PMG). METHODS: We retrospectively reviewed the medical charts, scalp, and intracranial video-EEG recordings, neuroimaging findings, and neuropsychological evaluations of four patients with refractory temporal lobe epilepsy related to PMG who consequently underwent resective surgery. KEY FINDINGS: High-resolution magnetic resonance imaging (MRI) revealed temporal lobe PMG in all cases, accompanied by hippocampal malrotation and closed lip schizencephaly in 3/4 cases, respectively. In intracranial recordings, interictal spike activity was localized within the PMG in only 2/4 and within the amygdala, hippocampus, and entorhinal cortex in all cases. In the first patient, two epileptogenic networks coexisted: the prevailing network initially involved the mesial temporal structures with spread to the anterior PMG; the secondary network successively involved the anterior part of the PMG and later the mesial temporal structures. In the second patient, the epileptogenic network was limited to the mesial temporal structures, fully sparing the PMG. In the third patient, the epileptogenic network first involved the mesial temporal structures and later the PMG. Conversely, in the last case, part of the PMG harbored an epileptogenic network that propagated to the mesial temporal structures. Consistent with these findings a favorable outcome (Engel class I in three of four patients; Engel class II in one of four) at last follow-up was obtained by a resection involving parts of the PMG cortex in three of four and anteromesial temporal lobe structures in another three of four cases. SIGNIFICANCE: Infrasylvian PMG displays a heterogeneous epileptogenicity and is occasionally and partially involved in the epileptogenic zone that commonly includes the mesial temporal structures. Our results highlight the intricate interrelations between the MRI-detectable lesion and the epileptogenic zone as delineated by intracranial recordings. Seizure freedom can be accomplished as a result of a meticulous intracranial study guiding a tailored resection that may spare part of the PMG.


Assuntos
Encéfalo/patologia , Epilepsia/patologia , Malformações do Desenvolvimento Cortical/patologia , Adolescente , Adulto , Encéfalo/cirurgia , Criança , Eletroencefalografia , Epilepsia/cirurgia , Feminino , Hipocampo/anormalidades , Hipocampo/patologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Malformações do Desenvolvimento Cortical/cirurgia , Rede Nervosa/patologia , Procedimentos Neurocirúrgicos/métodos , Tomografia por Emissão de Pósitrons , Lobo Temporal/patologia , Lobo Temporal/cirurgia , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem
19.
Brain ; 135(Pt 2): 631-40, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22036962

RESUMO

Thanks to the seminal work of Wilder Graves Penfield (1891-1976) at the Montreal Neurological Institute, electrical stimulation is used worldwide to localize the epileptogenic cortex and to map the functionally eloquent areas in the context of epilepsy surgery or lesion resections. In the functional map of elementary and experiential responses he described through >20 years of careful exploration of the human cortex via stimulation of the cortical surface, Penfield did not identify any 'pain cortical area'. We reinvestigated this issue by analysing subjective and videotaped behavioural responses to 4160 cortical stimulations using intracerebral electrodes implanted in all cortical lobes that were carried out over 12 years during the presurgical evaluation of epilepsy in 164 consecutive patients. Pain responses were scarce (1.4%) and concentrated in the medial part of the parietal operculum and neighbouring posterior insula where pain thresholds showed a rostrocaudal decrement. This deep cortical region remained largely inaccessible to the intraoperative stimulation of the cortical surface carried out by Penfield after resection of the parietal operculum. It differs also from primary sensory areas described by Penfield et al. in the sense that, with our stimulation paradigm, pain represented only 10% of responses. Like Penfield et al., we obtained no pain response anywhere else in the cortex, including in regions consistently activated by pain in most functional imaging studies, i.e. the first somatosensory area, the lateral part of the secondary somatosensory area, anterior and mid-cingulate gyri (mid-cingulate cortex), anterior frontal, posterior parietal and supplementary motor areas. The medial parietal operculum and posterior insula are thus the only areas where electrical stimulation is able to trigger activation of the pain cortical network and thus the experience of somatic pain.


Assuntos
Percepção da Dor/fisiologia , Dor/fisiopatologia , Córtex Somatossensorial/fisiopatologia , Adulto , Mapeamento Encefálico , Estimulação Elétrica , Eletrodos Implantados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
Epilepsy Behav ; 28(3): 408-12, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23872083

RESUMO

Four patients with refractory epilepsy and hypermotor seizures (HMS) benefited from an intracerebral investigation after a presurgical evaluation and demonstrated an ictal onset zone primarily involving the posterior cortex, specifically the posterior cingulate gyrus in two patients. At seizure onset, these two patients reported a falling sensation, followed by HMSs characterized by swinging movements of the trunk with intense grasping of the bed railing. The two other patients with lateral parietal seizure onset reported blurred vision and dizziness, followed by a mixed pattern of the previously described type 1 and 2 HMSs. Three patients have been operated on, including two class I of Engel after 36 and 52months of follow-up. One patient developed a postoperative infection and continues to suffer seizures. Pathological findings disclosed a type IIa focal cortical dysplasia in all the patients. The last patient is awaiting surgery. Posterior cortex epilepsies, including those originating from the posterior cingulate cortex, can be responsible for HMSs.


Assuntos
Epilepsias Parciais/complicações , Extremidades/fisiopatologia , Transtornos dos Movimentos/etiologia , Convulsões/etiologia , Adulto , Pré-Escolar , Eletroencefalografia , Feminino , Fluordesoxiglucose F18 , Humanos , Imageamento por Ressonância Magnética , Masculino , Transtornos dos Movimentos/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Adulto Jovem
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