Stratifying sudden death risk in adults with drug-resistant focal epilepsy: The SUDEP-CARE score.

BACKGROUND AND PURPOSE: A clinical risk score for sudden unexpected death in epilepsy (SUDEP) in patients with drug-resistant focal epilepsy could help improve prevention. METHODS: A case-control study was conducted including (i) definite or probable SUDEP cases collected by the French National Sentinel Mortality Epilepsy Network and (ii) control patients from the French national research database of epilepsy monitoring units. Patients with drug-resistant focal epilepsy were eligible. Multiple logistic regressions were performed. After sensitivity analysis and internal validation, a simplified risk score was developed from the selected variables. RESULTS: Sixty-two SUDEP cases and 620 controls were included. Of 21 potential predictors explored, seven were ultimately selected, including generalized seizure frequency (>1/month vs. <1/year: adjusted odds ratio [AOR] 2.6, 95% confidence interval [CI] 1.25-5.41), nocturnal or sleep-related seizures (AOR 4.49, 95% CI 2.68-7.53), current or past depression (AOR 2.0, 95% CI 1.19-3.34) or the ability to alert someone of an oncoming seizure (AOR 0.57, 95% CI 0.33-0.98). After internal validation, a clinically usable score ranging from -1 to 8 was developed, with high discrimination capabilities (area under the receiver operating curve 0.85, 95% CI 0.80-0.90). The threshold of 3 has good sensitivity (82.3%, 95% CI 72.7-91.8), whilst keeping a good specificity (82.7%, 95% CI 79.8-85.7). CONCLUSIONS: These results outline the importance of generalized and nocturnal seizures on the occurrence of SUDEP, and show a protective role in the ability to alert someone of an oncoming seizure. The SUDEP-CARE score is promising and will need external validation. Further work, including paraclinical explorations, could improve this risk score.

Coffee consumption and seizure frequency in patients with drug-resistant focal epilepsy.

OBJECTIVE: To assess the relation between coffee consumption and seizure frequency in patients with drug-resistant focal epilepsy. METHODS: Cross-sectional analysis of data collected in the SAVE study, which included patients with drug-resistant focal epilepsy during long-term EEG monitoring. Patients in whom both coffee consumption and data about seizure frequency, including focal to bilateral tonic-clonic seizures (FBTCS), were available were selected. Coffee consumption was collected using a standardized self-report questionnaire and classified into four groups: none, rare (from less than 1 cup/week to up 3 cups/week), moderate (from 4 cups/week to 3 cups/day), and high (more than 4 cups/day). RESULTS: Six hundred and nineteen patients were included. There was no relation between coffee consumption and total seizure frequency (p = 0.902). In contrast, the number of FBTCS reported over the past year was significantly associated with usual coffee consumption (p = 0.029). Specifically, number of FBCTS in patients who reported moderate coffee consumption was lower than in others. In comparison with patients with moderate coffee consumption, the odds ratio (95%CI) for reporting at least 1 FBTCS per year was 1.6 (1.03-2.49) in patients who never take coffee, 1.62 (1.02-2.57) in those with rare consumption and 2.05 (1.24-3.4) in those with high consumption. Multiple ordinal logistic regression showed a trend toward an association between coffee consumption and number of FBTCS (p = 0.08). CONCLUSIONS AND RELEVANCE: Our data suggest that effect of coffee consumption on seizures might depend on dose with potential benefits on FBTCS frequency at moderate doses. These results will have to be confirmed by prospective studies.

Impact of recommendations on sodium valproate prescription among women with epilepsy: An interrupted time-series study.

BACKGROUND: The European Medicines Agency (EMA) has developed risk minimization measures (RMMs) to reduce the use of the teratogenic drug, sodium valproate (VPA). The objective was to assess the impact of these RMMs among females with epilepsy in France. METHODS: We used data from the French National Health Insurance Database (SNDS), including 114,936 females aged under 50, with a reimbursement claim for an antiepileptic drug from January 2011 to December 2017, and identified as people with epilepsy. We used a controlled interrupted time series stratifying on age: girls (0-14 years old) and women of childbearing age (15-49 years), and with 129,917 males as controls. RESULTS: VPA prevalent use among girls and women of childbearing age with epilepsy decreased significantly after the issue of the RMMs (trend changes of, respectively, -5 and -4 users per 1000 females at-risk per quarter in comparison to the control group). We did not detect any significant change in VPA incident use. CONCLUSIONS: VPA use decreased over the study period among females with epilepsy but there were still 317 women and 206 girls started on VPA therapy VPA in 2017 (8 per 1000 at-risk and 18 per 1000, respectively). This suggests that either the measures should be strengthened or that the lowest level of VPA use has been reached. In this context, the introduction of a new RMM (in 2018) needs to be evaluated.

Audiogenic seizure as a model of sudden death in epilepsy: A comparative study between four inbred mouse strains from early life to adulthood.

OBJECTIVE: Mouse models of sudden unexpected death in epileptic patients (SUDEP) using audiogenic seizures (AGS) are valuable because death can occur following a sound-induced seizure in the absence of any pharmacologic or electric component. However, only a few strains of mice are AGS prone, and the vast majority of studies involve DBA/2 or DBA/1 inbred strains. With the goal of characterizing the variation of AGS susceptibility with age, and of offering a larger panel of mice available for AGS studies, we performed a comparative study of the variability in AGS responses. METHODS: The variation of AGS with age was determined in two classically used inbred strains of mice, DBA/2 and DBA/1, and two additional strains, BALB/c and 129/SvTer. As AGS-stimulated tonic seizures can be lethal or nonlethal, even in the same inbred strain, in a second experiment, we addressed whether there is an innate capacity to reproduce the same response after a tonic AGS, referred to as "determinism," in the DBA/2J, DBA/1J, and 129/SvTer mouse strains. RESULTS: Results show that the 129/SvTer mouse is a more versatile model of SUDEP due to its wider age range of susceptibility compared to the DBA/2J and DBA/1J mouse strains. In addition, we show that determinism is not consistently evident in DBA/2J and 129/SvTer strains after AGS. Hence, one cannot be certain that a lethal AGS will always be lethal in successive testing after resuscitation and vice versa in these two mouse strains. SIGNIFICANCE: These studies highlight the phenotypic variability of AGS in different mouse strains, show the value of an additional mouse strain, 129/SvTer, for studies using AGS, and thus provide valuable information for future studies of AGS and SUDEP.

The landscape of epilepsy-related GATOR1 variants.

PURPOSE: To define the phenotypic and mutational spectrum of epilepsies related to DEPDC5, NPRL2 and NPRL3 genes encoding the GATOR1 complex, a negative regulator of the mTORC1 pathway METHODS: We analyzed clinical and genetic data of 73 novel probands (familial and sporadic) with epilepsy-related variants in GATOR1-encoding genes and proposed new guidelines for clinical interpretation of GATOR1 variants. RESULTS: The GATOR1 seizure phenotype consisted mostly in focal seizures (e.g., hypermotor or frontal lobe seizures in 50%), with a mean age at onset of 4.4 years, often sleep-related and drug-resistant (54%), and associated with focal cortical dysplasia (20%). Infantile spasms were reported in 10% of the probands. Sudden unexpected death in epilepsy (SUDEP) occurred in 10% of the families. Novel classification framework of all 140 epilepsy-related GATOR1 variants (including the variants of this study) revealed that 68% are loss-of-function pathogenic, 14% are likely pathogenic, 15% are variants of uncertain significance and 3% are likely benign. CONCLUSION: Our data emphasize the increasingly important role of GATOR1 genes in the pathogenesis of focal epilepsies (>180 probands to date). The GATOR1 phenotypic spectrum ranges from sporadic early-onset epilepsies with cognitive impairment comorbidities to familial focal epilepsies, and SUDEP.

Correction to: The landscape of epilepsy-related GATOR1 variants.

The original version of this Article contained an error in the author list where the corresponding author Stéphanie Baulac was repeated twice. This has now been corrected in the HTML, the PDF was correct at the time of publication.

Correction: The landscape of epilepsy-related GATOR1 variants.

The original version of this article contained an error in the spelling of the author Erik H. Niks, which was incorrectly given as Erik Niks. This has now been corrected in both the PDF and HTML versions of the article.

Long-term negative impact of an inappropriate first antiepileptic medication on the efficacy of a second antiepileptic medication in mice.

Childhood absence epilepsy (CAE) is one of the most frequent epilepsies in infancy. The first-line recommended therapy for CAE is based on the prescription of the narrow-spectrum ethosuximide and the broad-spectrum valproic acid, which have similar efficacy in the first 12 months. Nevertheless, some antiepileptic drugs (AEDs) may worsen seizure duration and type in this syndrome. In line with this, we have encountered a case of identical twins with CAE and early exposure to different antiseizure drugs leading to divergent outcomes. From this, we hypothesized that the first AED to treat CAE may determine the long-term prognosis, especially in the developing brain, and that some situations leading to drug resistance may be explained by use of an inappropriate first AED. Therefore, we investigated this hypothesis by using a genetic mouse model of absence epilepsy (BS/Orl). Mice received a first appropriate or inappropriate AED followed by the same appropriate AED. Our data demonstrate that an inappropriate first AED has a negative impact on the long-term efficacy of a second appropriate AED. This work supports the necessity to effectively diagnose epileptic syndromes prior to medication use, particularly in children, in order to prevent the deleterious effects of an inappropriate initial AED.

Psychiatric and cognitive adverse events: A pooled analysis of three phase III trials of adjunctive eslicarbazepine acetate for partial-onset seizures.

OBJECTIVE: To evaluate the nature and incidence of psychiatric and cognitive adverse events (AEs) reported with eslicarbazepine acetate (ESL) used as adjunctive treatment for refractory partial-onset seizures (POS) in adults. METHODS: This was a post-hoc analysis of data pooled from three randomized double-blind, placebo-controlled trials (BIA-2093-301, -302, -304). After an 8-week baseline period, patients received placebo or adjunctive ESL 400mg (studies 301 and 302 only), 800mg, or 1200mg once daily (QD) for 14weeks (2-week titration period, 12-week maintenance period). Psychiatric and cognitive AEs were identified from individual patient data. Suicidality was also evaluated using the Columbia-Classification Algorithm of Suicide Assessment (C-CASA), or the Columbia-Suicide Severity Rating Scale (C-SSRS). P-values were obtained using the chi-square test of independence or Fisher's exact test, without correcting for multiplicity. RESULTS: The analysis population included 1447 patients (ESL, n=1021; placebo, n = 426). Psychiatric treatment-emergent AEs (TEAEs) occurred in 10.8% of patients receiving ESL, and in a comparable proportion (10.3%) of patients receiving placebo (p=0.802). The incidence of depression and suicidality-related TEAEs was higher for ESL (7.4%) vs. placebo (3.8%) (p=0.009). The occurrence of these TEAEs differed between treatment groups (p = 0.010), but there was no notable trend between increasing ESL dose and increasing incidence of depression and suicidality-related TEAEs. Aggression/hostility-related TEAEs occurred in <0.1% of patients taking ESL vs. 0.9% taking placebo. The incidence of cognitive TEAEs was higher for ESL (7.1%) vs. placebo (4.0%) (p=0.023); incidences of memory impairment, attention disturbance, apathy, and aphasia were higher for ESL 1200mg than for other treatment groups. Incidences of psychiatric and cognitive serious AEs (SAEs) were 0.6% and 0.2% with ESL, and 0.5% and 0% with placebo, respectively. Psychiatric and cognitive TEAEs leading to discontinuation occurred in 1.9% and 1.4% of patients taking ESL, and 0.7% and 0.5% taking placebo, respectively. CONCLUSIONS: In phase III clinical trials of adjunctive ESL for treatment-refractory POS, psychiatric and cognitive TEAEs were reported infrequently with ESL and placebo. The incidences of depression and suicidality-related TEAEs and of cognitive TEAEs were higher for patients taking ESL vs. placebo. Incidences of psychiatric and cognitive SAEs, and TEAEs leading to discontinuation, were low with ESL and placebo.

[Research and epilepsy]. / Recherche et épilepsie.

Advances in electroencephalography help identify the epileptic zone. It is now possible to locate the source of abnormalities on the patient's magnetic resonance imaging. For this, high resolution electroencephalogram is required. The software for this type of reconstruction are still being developed. If it is only one tool, research is progressing through simulations.

Identification of Interictal Epileptic Networks from Dense-EEG.

Epilepsy is a network disease. The epileptic network usually involves spatially distributed brain regions. In this context, noninvasive M/EEG source connectivity is an emerging technique to identify functional brain networks at cortical level from noninvasive recordings. In this paper, we analyze the effect of the two key factors involved in EEG source connectivity processing: (i) the algorithm used in the solution of the EEG inverse problem and (ii) the method used in the estimation of the functional connectivity. We evaluate four inverse solutions algorithms (dSPM, wMNE, sLORETA and cMEM) and four connectivity measures (r 2, h 2, PLV, and MI) on data simulated from a combined biophysical/physiological model to generate realistic interictal epileptic spikes reflected in scalp EEG. We use a new network-based similarity index to compare between the network identified by each of the inverse/connectivity combination and the original network generated in the model. The method will be also applied on real data recorded from one epileptic patient who underwent a full presurgical evaluation for drug-resistant focal epilepsy. In simulated data, results revealed that the selection of the inverse/connectivity combination has a significant impact on the identified networks. Results suggested that nonlinear methods (nonlinear correlation coefficient, phase synchronization and mutual information) for measuring the connectivity are more efficient than the linear one (the cross correlation coefficient). The wMNE inverse solution showed higher performance than dSPM, cMEM and sLORETA. In real data, the combination (wMNE/PLV) led to a very good matching between the interictal epileptic network identified from noninvasive EEG recordings and the network obtained from connectivity analysis of intracerebral EEG recordings. These results suggest that source connectivity method, when appropriately configured, is able to extract highly relevant diagnostic information about networks involved in interictal epileptic spikes from non-invasive dense-EEG data.

Familial focal epilepsy with focal cortical dysplasia due to DEPDC5 mutations.

OBJECTIVE: The DEPDC5 (DEP domain-containing protein 5) gene, encoding a repressor of the mTORC1 signaling pathway, has recently emerged as a major gene mutated in familial focal epilepsies. We aimed to further extend the role of DEPDC5 to focal cortical dysplasias (FCDs). METHODS: Seven patients from 4 families with DEPDC5 mutations and focal epilepsy associated with FCD were recruited and investigated at the clinical, neuroimaging, and histopathological levels. The DEPDC5 gene was sequenced from genomic blood and brain DNA. RESULTS: All patients had drug-resistant focal epilepsy, 5 of them underwent surgery, and 1 had a brain biopsy. Electroclinical phenotypes were compatible with FCD II, although magnetic resonance imaging (MRI) was typical in only 4 cases. Histopathology confirmed FCD IIa in 2 patients (including 1 MRI-negative case) and showed FCD I in 2 other patients, and remained inconclusive in the last 2 patients. Three patients were seizure-free postsurgically, and 1 had a worthwhile improvement. Sequencing of blood DNA revealed truncating DEPDC5 mutations in all 4 families; 1 mutation was found to be mosaic in an asymptomatic father. A brain somatic DEPDC5 mutation was identified in 1 patient in addition to the germline mutation. INTERPRETATION: Germline, germline mosaic, and brain somatic DEPDC5 mutations may cause epilepsy associated with FCD, reinforcing the link between mTORC1 pathway and FCDs. Similarly to other mTORopathies, a "2-hit" mutational model could be responsible for cortical lesions. Our study also indicates that epilepsy surgery is a valuable alternative in the treatment of drug-resistant DEPDC5-positive focal epilepsies, even if the MRI is unremarkable.

Long-term EEG in patients with the ring chromosome 20 epilepsy syndrome.

The recognizable electroencephalography (EEG) pattern of ring chromosome 20 epilepsy syndrome can be missing in patients with r(20) chromosomal anomaly, and may be found in patients with frontal lobe epilepsy of other origin. This study aims to search for more specific EEG signs by using long-term recordings and measuring the duration of paroxysmal anomalies. The series included 12 adult patients with r(20) anomaly, and 12 controls without any chromosomal aberration. We measured the duration of every paroxysmal burst and calculated the sum of their durations for each long-term EEG recording. We compared patients to controls using the Mann-Whitney U-test. Every patient showed long-lasting paroxysmal EEG bursts, up to 60 min; controls did not show any bursts longer than 60 s (p < 0.0001). The total duration of paroxysmal anomalies was significantly longer in patients (31-692 min) compared to controls (0-48 min) (p < 0.0001). Thus, long-term recordings enhance the contribution of EEG methods for characterizing the ring 20 chromosome epilepsy syndrome.

Cost-effectiveness analysis of epilepsy surgery in a controlled cohort of adult patients with intractable partial epilepsy: A 5-year follow-up study.

OBJECTIVE: Despite its well-known effectiveness, the cost-effectiveness of epilepsy surgery has never been demonstrated in France. We compared cost-effectiveness between resective surgery and medical therapy in a controlled cohort of adult patients with partial intractable epilepsy. METHODS: A prospective cohort of adult patients with surgically remediable and medically intractable partial epilepsy was followed over 5 years in the 15 French centers. Effectiveness was defined as 1 year without a seizure, based on the International League Against Epilepsy (ILAE) classification. Clinical outcomes and direct costs were compared between surgical and medical groups. Long-term direct costs and effectiveness were extrapolated over the patients' lifetimes with a Monte-Carlo simulation using a Markov model, and an incremental cost-effectiveness ratio (ICER) was computed. Indirect costs were also evaluated. RESULTS: Among the 289 enrolled surgery candidates, 207 were operable-119 in the surgical group and 88 in the medical group-65 were not operable and not analyzed here, 7 were finally not eligible, and 10 were not followed. The proportion of patients completely seizure-free during the last 12 months (ILAE class 1) was 69.0% in the operated group and 12.3% in the medical group during the second year (p < 0.001), and it was respectively 76.8% and 21% during the fifth year (p < 0.001). Direct costs became significantly lower in the surgical group the third year after surgery, as a result of less antiepileptic drug use. The value of the discounted ICER was 10,406 (95% confidence interval [CI] 10,182-10,634) at 2 years and 2,630 (CI 95% 2,549-2,713) at 5 years. Surgery became cost-effective between 9 and 10 years after surgery, and even earlier if indirect costs were taken into account as well. SIGNIFICANCE: Our study suggests that in addition to being safe and effective, resective surgery of epilepsy is cost-effective in the medium term. It should therefore be considered earlier in the development of epilepsy.

Eslicarbazepine acetate as adjunctive therapy in patients with uncontrolled partial-onset seizures: Results of a phase III, double-blind, randomized, placebo-controlled trial.

OBJECTIVE: To evaluate the efficacy and safety of adjunctive eslicarbazepine acetate (ESL) in patients with refractory partial-onset seizures. METHODS: This randomized, placebo-controlled, double-blind, parallel-group, phase III study was conducted at 173 centers in 19 countries, including the United States and Canada. Eligible patients were aged ≥16 years and had uncontrolled partial-onset seizures despite treatment with 1-2 antiepileptic drugs (AEDs). After an 8-week baseline period, patients were randomized to once-daily placebo (n = 226), ESL 800 mg (n = 216), or ESL 1,200 mg (n = 211). Following a 2-week titration period, patients received ESL 800 or 1,200 mg once-daily for 12 weeks. Seizure data were captured and documented using event-entry or daily entry diaries. RESULTS: Standardized seizure frequency (SSF) during the maintenance period (primary end point) was reduced with ESL 1,200 mg (p = 0.004), and there was a trend toward improvement with ESL 800 mg (p = 0.06), compared with placebo. When data for titration and maintenance periods were combined, ESL 800 mg (p = 0.001) and 1,200 mg (p < 0.001) both reduced SSF. There were no statistically significant interactions between treatment response and geographical region (p = 0.38) or diary version (p = 0.76). Responder rate (≥50% reduction in SSF) was significantly higher with ESL 1,200 mg (42.6%, p < 0.001) but not ESL 800 mg (30.5%, p = 0.07) than placebo (23.1%). Incidence of treatment-emergent adverse events (TEAEs) and TEAEs leading to discontinuation increased with ESL dose. The most common TEAEs were dizziness, somnolence, nausea, headache, and diplopia. SIGNIFICANCE: Adjunctive ESL 1,200 mg once-daily was more efficacious than placebo in adult patients with refractory partial-onset seizures. The once-daily 800 mg dose showed a marginal effect on SSF, but did not reach statistical significance. Both doses were well tolerated. Efficacy assessment was not affected by diary format used.

An instrument to assess patient satisfaction with epilepsy treatment.

AIMS: Patient satisfaction with antiepileptic drugs is an important component in the management of epilepsy. This study aimed to develop a visual analog scale (VAS) to evaluate patient satisfaction with the effectiveness and tolerability of the current antiepileptic treatment and to identify the most appropriate threshold scores of patient dissatisfaction predictive of a decision to change the antiepileptic drugs. METHODS: This observational study was conducted among patients with epilepsy consulting a neurologist in France. Two anonymous questionnaires were used, one for patients and one for neurologists. The patients' questionnaire assessed satisfaction using a four-point Likert scale and a 10-centimeter VAS. The neurologists' questionnaire evaluated whether the neurologist decided to change the current treatment or not. The determination of the threshold scores predictive of patient dissatisfaction correlated with a change of the medication was performed using analyses of receiver operating characteristic curves. Visual analogue scale scores collected from the patient questionnaire were tested against the responses collected from the neurologist questionnaire. RESULTS: Five hundred eighteen patient questionnaires and five hundred seven neurologist questionnaires were completed. For the satisfaction with effectiveness and tolerability, the mean VAS scores were 6.7±2.8 and 7.0±2.8, respectively and were, respectively, 6.9±1.7 and 7.0±1.6 for patients who declared to be satisfied with their current antiepileptic drugs and were, respectively, 3.4±1.7 and 3.3±1.9 for those who declared to be dissatisfied. The neurologist decided to change the current antiepileptic drugs in 41.1% (n=208) of the cases principally because of inadequate effectiveness. With respect to the receiver operating characteristic curves, a VAS threshold of 6 would correctly predict the decision to change the current antiepileptic drugs with sensitivity and specificity values over 73% for both effectiveness and tolerability. CONCLUSIONS: The VAS developed in this study can help patients to evaluate their antiepileptic drugs and to facilitate timely treatment modification when the current treatment is unsatisfactory.

Brand name to generic substitution of antiepileptic drugs does not lead to seizure-related hospitalization: a population-based case-crossover study.

PURPOSE: There is still controversy on brand-to-generic (B-G) antiepileptic drugs (AEDs) substitution. METHODS: To assess association between B-G AED substitution and seizure-related hospitalization, we designed a case crossover using the French National Health Insurance Database. We identified a cohort of adult patients who filled a prescription in 2009-2011 for AEDs with at least one brand name and one generic form. The outcome date was defined as the date of hospitalization, coded G40.x or G41.x, with a G40/G41 hospitalization-free period of at least 1 year. Patients with a medical history of cancer and women who gave birth in 2009-2011 were excluded. We required individuals to have regular dispensations of AEDs within the year preceding the outcome date. Free patients were defined as patients who had only brand name dispensations before the control period. RESULTS: Eight thousand three hundred seventy nine patients (mean age ± standard deviation, 52.7 ± 18.8 years; sex ratio male/female, 1.27) were analyzed. Discordant pairs were 491 with B-G substitution in the control period only and 478 with B-G substitution in the case period only; odds ratio (95% confidence interval) 0.97 (0.86-1.10). No statistically significant interaction was detected among the four prespecified subgroup analyses (gender, age strata, free or non-free, and strict AED monotherapy or not). Controlling for non-seizure-related hospitalizations made no material difference. Sensitivity analyses yielded similar results. CONCLUSIONS: Brand-to-generic AED substitution was not associated with an elevated risk of seizure-related hospitalization.

Distinct hyperexcitability mechanisms underlie fast ripples and epileptic spikes.

OBJECTIVE: In partial epilepsies, interictal epileptic spikes (IESs) and fast ripples (FRs) represent clinically relevant biomarkers characteristic of epileptogenic networks. However, their specific significance and the pathophysiological changes leading to either FRs or IESs remain elusive. The objective of this study was to analyze the conditions in which hyperexcitable networks can generate either IESs or FRs and to reveal shared or distinct mechanisms that underlie both types of events. METHODS: This study is the first to comparatively analyze mechanisms that induce either IESs or FRs using an approach that combines computational modeling and experimental data (in vivo and in vitro). A detailed CA1 hippocampal network model is introduced. A parameter sensitivity analysis was conducted to determine which model parameters (cell related and network related) allow the most accurate simulation of FRs and IESs. RESULTS: Our model indicates that although FRs and IESs share certain common mechanisms (shifted gamma-aminobutyric acid [GABA]A reversal potential, altered synaptic transmission), there are also critical differences in terms of number of pyramidal cells involved (small vs large), spatial distribution of hyperexcitable pyramidal cells (clustered vs uniform), and firing patterns (weakly vs highly synchronized). In vitro experiments verified that subtle changes in GABAergic and glutamatergic transmission favor either FRs or IESs, as predicted by the model. INTERPRETATION: This study provides insights into the interpretation of 2 interictal markers observed in intracerebral electroencephalographic data. Depending on the degree and spatiotemporal features of hyperexcitability, not only IESs or FRs are generated but also transitions between both types of events.

Shape features of epileptic spikes are a marker of epileptogenesis in mice.

PURPOSE: To identify reliable biomarkers for quantitatively assessing the development of epilepsy in brain. METHODS: In a kainate mouse model of temporal lobe epilepsy, we performed long-term video-electroencephalography (EEG) monitoring (several weeks) of freely moving animals, from kainic acid injection to chronic epileptic stage. Using signal processing techniques, we automatically detected single epileptic spikes (ESs), and we quantified the evolution of shape features during the epileptogenesis process. Using a computational model of hippocampal activity (neuronal population level), we investigated excitatory-related and inhibitory-related parameters involved in morphologic changes of ESs. KEY FINDINGS: The frequency of ESs increases during epileptogenesis. Regarding shape features, we found that both the initial spike component and the wave component of opposite polarity of ESs gradually increase during epileptogenesis. These very specific alterations of the shape of ESs were reproduced in a computational physiologically relevant neuronal population model. Using this model, we disclosed some key parameters (related to glutamatergic and γ-aminobutyric acid [GABA]ergic synaptic transmission) that explain the shape features of simulated ESs. Of interest, the model predicted that the decrease of GABAergic inhibition is responsible for the increase of the wave component of ESs. This prediction (at first sight counterintuitive) was verified in both in vivo and in vitro experiments. Finally, from aforementioned electrophysiologic features, we devised a novel and easily computable index (wave area/spike amplitude ratio) indicative of the progression of the disease (early vs. late stage). SIGNIFICANCE: Results suggest that dendritic inhibition in hippocampal circuits undertake dramatic changes over the latent period. These changes are responsible for observed modifications in the shape of ESs recorded in local field potential (LFP) signals. The proposed index may constitute a biomarker of epileptogenesis.

Management and monitoring of patients treated with zonisamide: the OZONE study.

AIM: To characterise patients treated with zonisamide in everyday practice and describe the effectiveness and tolerability of treatment. METHODS: This was an observational, longitudinal, naturalistic study, conducted by neurologists in France. Patients who had started zonisamide treatment at least three months prior to inclusion were eligible. Data were collected at routine consultations at inclusion (Visit 1) and three to six months later (Visit 2). At Visit 1, investigators documented epilepsy-related variables based on patient records before initiation of zonisamide and at inclusion. At Visit 2, the investigators re-evaluated seizure activity and rated effectiveness. Adverse events were also documented. RESULTS: A total of 428 patients were included in the study based on evaluation by 132 neurologists. Zonisamide was initiated at a daily dose of 50 mg and 25 mg in 61% and 31.8% of patients, respectively. The median maintenance dose was 300 mg/day. Prior to initiation of zonisamide, the mean seizure frequency was 16.0 seizures/month. This was reduced to 8.7 seizures/month at Visit 1 and to 7.1 seizures/month at Visit 2. The response rate and proportion of seizure-free patients was 61.9 and 31.1% at Visit 1 and 65.9 and 25.6% at Visit 2, respectively. The frequency of seizures at Visit 2 decreased significantly (p<0.05) for all seizure type subgroups, except for simple partial seizures. Responder rates were >60% for all analysed subgroups. The proportion of seizure-free patients was significantly higher in patients receiving bitherapy, compared to the others (p=0.007). The most frequently reported adverse event was somnolence (5.1%); three serious adverse events were reported. CONCLUSION: In everyday practice, zonisamide is principally used in association with other antiepileptic drugs for the treatment of focal epilepsy in adults. It is effective in improving seizure control and quality of life, and is generally well-tolerated.