The role of stereoelectroencephalography (SEEG) in reevaluation of epilepsy surgery failures.

Management of patients after initial epilepsy surgical failure is challenging. In this study, we report our experience in using the stereoelectroencephalography (SEEG) method in the reevaluation of patients after initial epilepsy surgical failure. We selected 28 patients examined through SEEG in our department for drug-resistant focal epilepsy following initial epilepsy surgical failure. For each patient, the residual seizure onset zone (rSOZ) as defined by SEEG was classified as either contiguous if the seizure onset zone (SOZ) was focal and close to the surgical cavity (same lobe) or noncontiguous in cases where the SOZ included site(s) distant from the surgical cavity. The rSOZ was defined according to visual analysis of SEEG traces completed by an estimation of the epileptogenicity index (EI). A second surgical procedure was performed in 12 patients (45%). A favorable outcome (Engel class I or II) was obtained in 9/12 patients (6 in Engel class I, 50%). The proportion of patients that had reoperation was higher in the contiguous group (80%) than in the noncontiguous group (22%) (p=0.02). A rSOZ localized in close relation to the initial surgical resection zone (contiguous group) was found in 10 patients (35%). Among them, 8 have since undergone reoperation, and a good outcome (Engel class I) was achieved in 5/8 (63%). A rSOZ involving a distant region from the first surgery was observed in 18 patients (65%) (noncontiguous group). Among them, only 4 have undergone reoperation, leading to a failure in 2 (Engel class III or IV) and a good outcome in 2 (IA). Ten patients had a first standard temporal lobectomy, and in 50% of these cases, the insula was involved in the rSOZ. Stereoelectroencephalography offers a unique way to evaluate the rSOZ at the individual level and thus guide further surgical decision-making. The best results are observed in patients having a focal rSOZ close to the site of the surgical resection in the first surgery.

One step closer to a global tool for rapid screening of major depression in epilepsy: validation of the French NDDI-E.

OBJECTIVE: Depression in people with epilepsy (PWE) is underdiagnosed and undertreated. The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is a screening questionnaire used for detecting major depressive episode (MDE) in PWE, and is already validated in 10 languages. However a version in French, one of the world's widely spoken languages, was, until now, lacking. We aimed to translate and validate the French NDDI-E. METHODS: This study was performed under the auspices of the ILAE. People with epilepsy >18years of age were recruited from 2 specialist epilepsy units in Marseille, France. Two native French speakers and 2 native English speakers performed a forward-backward translation. The Mini International Neuropsychiatric Interview (MINI) was performed as the gold standard, and the Center for Epidemiological Studies Depression symptoms index (CES-D) was performed for external validity. Data were compared between PWE with MDE and PWE without MDE using the chi-square test and Student's t-test. Internal structural validity, external validity, and receiver operator characteristics were analyzed. RESULTS: Testing was performed on 116 PWE: mean age=40.39years (SD=13.83, range: [18-81]years old); 58.6% (68) were women; 87.1% had focal epilepsy. Using the MINI, we found that 33 (28.4%) patients had current MDE and that 15 (12.9%) patients had dysthymia; also, we found that 37 (31.9%) patients presented suicidal ideation and/or behavior. Cronbach's alpha coefficient was 0.838, indicating satisfactory internal consistency. Correlation between the NDDI-E and the CES-D scores was high (r(116)=0.817, p<0.0001), indicating good external validity. Receiver operator characteristic analysis showed an area under the curve of 0.958 (95% CI=0.904-0.986), (p<0.0001), indicating good capacity of the NDDI-E to detect MDE (defined by MINI). The cutoff for maximal sensitivity and specificity was 15. The mean NDDI-E score in PWE with MDE was 18.27 (SD=2.28), and the mean NDDI-E score in PWE without MDE was 10.61 (SD=3.63). SIGNIFICANCE: This study validated the French NDDI-E, with a cutoff score of 15/24 for MDE, similar to previous studies, and reinforces the NDDI-E as a global tool for detection of MDE.

Hyperkinetic motor seizures: a common semiology generated by two different cortical seizure origins.

We report a 37-year-old, right-handed patient with drug-resistant focal epilepsy whose seizures were characterized by explosive hyperkinetic behaviour. Video-SEEG revealed bifocal organization of epilepsy with two distinct cortical origins of seizures: the right temporal pole and left temporal lateral and perisylvian cortex. Irrespective of the cortical pattern of seizure onset, the hyperkinetic semiology was extremely similar. This supports a major role for "final common pathway" subcortical circuits in the genesis of the hyperkinetic semiology in this patient.

Beyond the lesion: the epileptogenic networks around cavernous angiomas.

The relationship between epileptogenic lesions and the extension of epileptogenicity is a major challenge in presurgical evaluation of drug resistant epilepsies. In this study, we aimed at quantifying the epileptogenic properties of brain structures explored by depth electrodes in patients investigated by stereoelectroencephalography (SEEG) and suffering from focal drug-resistant epilepsy associated with cavernous angioma (CA). Epileptogenicity of the perilesional region and distant brain areas was calculated according to the "epileptogenicity index" (EI), a technique that allows mathematical quantification of rapid discharges at seizure onset taking into account the time at which the discharge occurs. Thirteen seizures from 6 patients were studied. Localization of the cavernoma was the frontal lobe (two cases), the temporal lobe (three cases) or the anterior insula (one case). Visual inspection of the ictal discharge showed that in the majority of cases (5/6) the perilesional region was either not involved or involved with other distant sites. Using EI quantification, complex patterns of epileptogenicity were observed in five patients. A large number of brain regions out of the lesional region disclosed higher values than the lesion site. Mean values in the perilesional region and in the extralesional sites were not significantly different (p=0.34). Complex organization of the epileptogenic zone may be found in drug-resistant CA associated epilepsy. Thus, this result should be borne in mind when patients with CA and drug resistant epilepsy are investigated. If there is a suspicion of a larger epileptogenic zone than the lesion, intra-cerebral exploration by SEEG may be required before surgery that may be guided by the definition of the EZ.

Metabolic brain PET pattern underlying hyperkinetic seizures.

This study aims to contribute to the identification of selective brain regions involved in hyperkinetic behaviors. We studied the whole-brain voxel-based interictal metabolic 18FDG-PET pattern of 23 patients with hyperkinetic seizures, in comparison with both 15 healthy subjects similar for age and gender, and 23 patients without hyperkinetic seizures. Patients were in particular similar for the localization of the epileptogenic zone, this having been defined using stereoelectroencephalography (SEEG) when clinically indicated (15/23 patients with hyperkinetic seizures and 13/23 patients without hyperkinetic seizures). Using conjunction voxel-based analysis, patients with hyperkinetic seizures exhibited significant hypometabolism within bilateral midbrain and the right caudate head, in comparison both to healthy subjects (p<0.05, FDR-corrected for the voxel) and to patients without hyperkinetic seizures (p<0.0167, uncorrected for the voxel). Findings were secondarily confirmed separately in each subgroup of patients with frontal, temporal or posterior epilepsy. These findings argue for a specific subcortical metabolic impairment in patients with hyperkinetic seizures, within brain structures supposed to be involved in the generation of primitive motor programs.