De novo GABRG2 mutations associated with epileptic encephalopathies.

Epileptic encephalopathies are a devastating group of severe childhood onset epilepsies with medication-resistant seizures and poor developmental outcomes. Many epileptic encephalopathies have a genetic aetiology and are often associated with de novo mutations in genes mediating synaptic transmission, including GABAA receptor subunit genes. Recently, we performed next generation sequencing on patients with a spectrum of epileptic encephalopathy phenotypes, and we identified five novel (A106T, I107T, P282S, R323W and F343L) and one known (R323Q) de novo GABRG2 pathogenic variants (mutations) in eight patients. To gain insight into the molecular basis for how these mutations contribute to epileptic encephalopathies, we compared the effects of the mutations on the properties of recombinant α1ß2γ2L GABAA receptors transiently expressed in HEK293T cells. Using a combination of patch clamp recording, immunoblotting, confocal imaging and structural modelling, we characterized the effects of these GABRG2 mutations on GABAA receptor biogenesis and channel function. Compared with wild-type α1ß2γ2L receptors, GABAA receptors containing a mutant γ2 subunit had reduced cell surface expression with altered subunit stoichiometry or decreased GABA-evoked whole-cell current amplitudes, but with different levels of reduction. While a causal role of these mutations cannot be established directly from these results, the functional analysis together with the genetic information suggests that these GABRG2 variants may be major contributors to the epileptic encephalopathy phenotypes. Our study further expands the GABRG2 phenotypic spectrum and supports growing evidence that defects in GABAergic neurotransmission participate in the pathogenesis of genetic epilepsies including epileptic encephalopathies.

Neuronal networks in epileptic encephalopathies with CSWS.

OBJECTIVE: The aim of our study was to investigate the neuronal networks underlying background oscillations of epileptic encephalopathy with continuous spikes and waves during slow sleep (CSWS). METHODS: Sleep electroencephalography (EEG) studies before and after the treatment were investigated in 15 patients with CSWS. To investigate functional and effective connectivity within the network generating the delta activity in the background sleep EEG, the methods of dynamic imaging of coherent sources (DICS) and renormalized partial directed coherence (RPDC) were applied. RESULTS: Independent of etiology and severity of epilepsy, background EEG pattern in patients with CSWS before treatment is associated with the complex network of coherent sources in medial prefrontal cortex, somatosensory association cortex/posterior cingulate cortex, medial prefrontal cortex, middle temporal gyrus/parahippocampal gyrus/insular cortex, thalamus, and cerebellum. The analysis of information flow within this network revealed that the medial parietal cortex, the precuneus, and the thalamus act as central hubs, driving the information flow to other areas, especially to the temporal and frontal cortex. The described CSWS-specific pattern was no longer observed in patients with normalized sleep EEG. In addition, frequency of spiking showed a strong linear correlations with absolute source power, source coherence strength, and source RPDC strength at both time points: (1) Spike and wave index (SWI) versus absolute source power at EEG1 (r = 0.56; p = 0.008) and at EEG2 (r = 0.45; p = 0.009); (2) SWI versus source coherence strength at EEG1 (r = 0.71; p = 0.005) and at EEG2 (r = 0.52; p = 0.006); and (3) SWI versus source RPDC strength at EEG1 (r = 0.65; p = 0.003) and at EEG2 (r = 0.47; p = 0.009). SIGNIFICANCE: The leading role of the precuneus and thalamus in the hierarchical organization of the network underlying the background EEG points toward the significance of fluctuations of vigilance in the generation of CSWS. This hierarchical network organization appears to be specific for CSWS as it is resolved after successful treatment.

Costs of epilepsy and cost-driving factors in children, adolescents, and their caregivers in Germany.

OBJECTIVE: To provide first data on the cost of epilepsy and cost-driving factors in children, adolescents, and their caregivers in Germany. METHODS: A population-based, cross-sectional sample of consecutive children and adolescents with epilepsy was evaluated in the states of Hessen and Schleswig-Holstein (total of 8.796 million inhabitants) in all health care sectors in 2011. Data on socioeconomic status, course of epilepsy, and direct and indirect costs were recorded using patient questionnaires. RESULTS: We collected data from 489 children and adolescents (mean age ± SD 10.4 ± 4.2 years, range 0.5-17.8 years; 264 [54.0%] male) who were treated by neuropediatricians (n = 253; 51.7%), at centers for social pediatrics ("Sozialpaediatrische Zentren," n = 110, 22.5%) and epilepsy centers (n = 126; 25.8%). Total direct costs summed up to €1,619 ± €4,375 per participant and 3-month period. Direct medical costs were due mainly to hospitalization (47.8%, €774 ± €3,595 per 3 months), anticonvulsants (13.2%, €213 ± €363), and ancillary treatment (9.1%, €147 ± €344). The total indirect costs amounted to €1,231 ± €2,830 in mothers and to €83 ± €593 in fathers; 17.4% (n = 85) of mothers and 0.6% (n = 3) of fathers reduced their working hours or quit work because of their child's epilepsy. Independent cost-driving factors were younger age, symptomatic cause, and polytherapy with anticonvulsants. Older age, active epilepsy, symptomatic cause, and polytherapy were independent predictors of higher antiepileptic drug (AED) costs, whereas younger age, longer epilepsy duration, symptomatic cause, disability, and parental depression were independent predictors for higher indirect costs. SIGNIFICANCE: Treatment of children and adolescents with epilepsy is associated with high direct costs due to frequent inpatient admissions and high indirect costs due to productivity losses in mothers. Direct costs are age-dependent and higher in patients with symptomatic epilepsy and polytherapy. Indirect costs are higher in the presence of a child's disability and parental depression.

Evaluation of health-care utilization in patients with Dravet syndrome and on adjunctive treatment with stiripentol and clobazam.

Dravet syndrome (DS) is a rare, severe childhood epilepsy syndrome that imposes a substantial burden on patients and their caregivers. This study evaluated health-care utilization over a 2-year period in patients with DS at an outpatient clinic of a German epilepsy center. Data on the course of epilepsy, anticonvulsant treatment, and direct costs were recorded using the electronic seizure diary Epivista and patients' files. We enrolled 13 patients with DS (6 females, mean age: 12.3±7.5 years) between 2007 and 2010 and evaluated them during a 1-year baseline. All patients had drug-resistant epilepsy and their seizures failed to improve with a mean number of 6.7±3.4 anticonvulsants. They had an overall mean seizure frequency of 102.1 seizures per year (median: 31, range: 3-538) with 43.2 GTCSs per year (median: 14, range: 0-228). We estimated the annual total direct costs at €6506±3974 (range: €1174-11,783) per patient with hospitalization (68.9% of total direct costs) as the major cost factor ahead of costs for anticonvulsants (24.0%). For the 1-year follow-up period, less severely affected patients were continued on conventional anticonvulsants (n=4) or switched to adjunctive treatment with stiripentol and clobazam (n=9). In the latter group, six patients (67%) were long-term responders, with between 25% and 100% seizure reduction with respect to either GTCSs or the overall seizure frequency. This reduction in seizure frequency was associated with a shift in the distribution of cost components towards higher medication costs and decreased hospitalization costs. The total direct costs increased by 42.7%, mainly due to the newly introduced stiripentol, with an annual cost of €6610. This study showed that direct costs of patients with DS were above the average European costs of drug-resistant epilepsy in children. Treatment with new anticonvulsants resulted in reduction of seizures and inpatient admissions.

Variability of EEG-fMRI findings in patients with SCN1A-positive Dravet syndrome.

PURPOSE: Dravet syndrome (DS) or severe myoclonic epilepsy of infancy is an intractable epileptic encephalopathy of early childhood that is caused by a mutation in the SCN1A gene in most patients. The aim of this study was to identify a syndrome-specific epileptic network underlying interictal epileptiform discharges (IEDs) in patients with DS. METHODS: Ten patients with the diagnosis of DS associated with mutations in the SCN1A gene were investigated using simultaneous recording of electroencephalography and functional magnetic resonance imaging ((EEG-fMRI). Time series of IEDs were used as regressors for the statistical fMRI analysis. KEY FINDINGS: In nine patients with DS, individual blood oxygenation level-dependent (BOLD) signal changes were seen. In three patients the thalamus was involved. Furthermore, regions of the default mode network were activated in seven patients. However, a common activation pattern associated with IEDs could not be detected. SIGNIFICANCE: The study demonstrates that, despite a common genetic etiology in DS, different neuronal networks underlie the individual IEDs.

EEG-fMRI in atypical benign partial epilepsy.

Atypical benign partial epilepsy (ABPE) is a subgroup among the idiopathic focal epilepsies of childhood. Aim of this study was to investigate neuronal networks underlying ABPE and compare the results with previous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) studies of related epilepsy syndromes. Ten patients with ABPE underwent simultaneous EEG-fMRI recording. In all 10 patients several types of interictal epileptiform discharges (IEDs) were recorded. Individual IED-associated blood oxygen level-dependent (BOLD) signal changes were analyzed in a single subject analysis for each IED type (33 studies). A group analysis was also performed to determine common BOLD signal changes across the patients. IED-associated BOLD signal changes were found in 31 studies. Focal BOLD signal changes concordant with the spike field (21 studies) and distant cortical and subcortical BOLD signal changes (31 studies) were detected. The group analysis revealed a thalamic activation. This study demonstrated that ABPE is characterized by patterns similar to studies in rolandic epilepsy (focal BOLD signal changes in the spike field) as well as patterns observed in continuous spikes and waves during slow sleep (CSWS) (distant BOLD signal changes in cortical and subcortical structures), thereby underscoring that idiopathic focal epilepsies of childhood form a spectrum of overlapping syndromes.

Neuronal networks in west syndrome as revealed by source analysis and renormalized partial directed coherence.

West syndrome is a severe epileptic encephalopathy of infancy with a poor developmental outcome. This syndrome is associated with the pathognomonic EEG feature of hypsarrhythmia. The aim of the study was to describe neuronal networks underlying hypsarrhythmia using the source analysis method (dynamic imaging of coherent sources or DICS) which represents an inverse solution algorithm in the frequency domain. In order to investigate the interaction within the detected network, a renormalized partial directed coherence (RPDC) method was also applied as a measure of the directionality of information flow between the source signals. Both DICS and RPDC were performed for EEG delta activity (1-4 Hz) in eight patients with West syndrome and in eight patients with partial epilepsies (control group). The brain area with the strongest power in the given frequency range was defined as the reference region. The coherence between this reference region and the entire brain was computed using DICS. After that, the RPDC was applied to the source signals estimated by DICS. The results of electrical source imaging were compared to results of a previous EEG-fMRI study which had been carried out using the same cohort of patients. As revealed by DICS, delta activity in hypsarrhythmia was associated with coherent sources in the occipital cortex (main source) as well as the parietal cortex, putamen, caudate nucleus and brainstem. In patients with partial epilepsies, delta activity could be attributed to sources in the occipital, parietal and sensory-motor cortex. In West syndrome, RPDC showed the strongest and most significant direction of ascending information flow from the brainstem towards the putamen and cerebral cortex. The neuronal network underlying hypsarrhythmia in this study resembles the network which was described in previous EEG-fMRI and PET studies with involvement of the brainstem, putamen and cortical regions in the generation of hypsarrhythmia. The RPDC suggests that brainstem could have a key role in the pathogenesis of West syndrome. This study supports the theory that hypsarrhythmia results from ascending brainstem pathways that project widely to basal ganglia and cerebral cortex.

Concentrations of stiripentol in children and adults with epilepsy: the influence of dose, age, and comedication.

BACKGROUND: Stiripentol (STP) was approved as an orphan drug in 2007 in Europe as adjunctive therapy with valproic acid (VPA) and clobazam (CLB) for Dravet syndrome. Dravet syndrome is a highly pharmacoresistant form of epilepsy, which starts in early childhood. Data about STP pharmacokinetics and interactions are still limited and in part inconsistent. The aim of our study was to analyze the effect of age, gender, daily STP dose per body weight (milligrams per kilogram), VPA, CLB, and enzyme-inducing antiepileptic drugs on STP concentration-to-dose ratio (CDR), STP clearance, and STP trough concentrations. METHODS: Retrospectively, 220 STP serum concentrations in 75 patients from 3 German Epilepsy Centers were analyzed. Analysis of variance, regression analysis, and generalized estimating equations were used for statistical analysis. RESULTS: Our findings confirm the nonlinear STP pharmacokinetics. At steady state, STP CDR increased with daily STP doses. Compared with patients older than 12 years, STP concentrations were decreased by 39.6% in children aged 6-12 years (P < 0.001) and by 57.5% in children younger than 6 years (P < 0.001). Phenobarbital and phenytoin decreased STP concentrations by 63.2%. This effect was highly significant (P < 0.001), despite the small number of patients (n = 7) treated with phenobarbital or phenytoin. VPA had no significant effect on STP serum concentrations, whereas STP serum concentrations were moderately but significantly increased by CLB (24.6%, P = 0.011). CONCLUSIONS: Therapeutic drug monitoring of STP seems to be useful because of the wide variation of STP CDR, the nonlinear concentration-to-dose relationship, age-dependent pharmacokinetics, and drug-drug interactions.

EEG-fMRI reveals activation of brainstem and thalamus in patients with Lennox-Gastaut syndrome.

PURPOSE: Even if etiologies of Lennox-Gastaut syndrome (LGS) are diverse, the multiple causes converge into a final common pathway that results in this specific epilepsy phenotype. There is little knowledge, however, about neuronal networks that may be a part of this pathway. METHODS: To investigate these networks, 11 children with LGS and 9 control children with multifocal epileptic activity were investigated using simultaneous recordings of EEG and functional MRI (EEG-fMRI) in a 3 Tesla scanner. KEY FINDINGS: Individual and group analyses revealed significant activation of brainstem and thalamus (especially centromedian and anterior thalamus) associated with epileptiform discharges in patients with LGS. None of the patients with multifocal epileptic activity presented with the same hemodynamic activation pattern. SIGNIFICANCE: Because brainstem activation has been associated with infantile spasms, which often evolve into LGS, and thalamus activation has been observed in patients with primary (idiopathic generalized syndromes) and secondary (focal epilepsies) bilateral synchrony, the described network in LGS may represent the common pathogenetic pathway of these different conditions.

Valproate reduces spontaneous generalized spikes and waves but not photoparoxysmal reactions in patients with idiopathic generalized epilepsies.

PURPOSE: Patients with idiopathic generalized epilepsies (IGEs) often present with interictal spike-wave discharges (SWDs) at rest (spontaneous SWDs), during hyperventilation, and in response to photic stimulation (photoparoxysmal response or PPR). Valproic acid (VPA) is a first-line antiepileptic drug for therapy of patients with IGE. Herein we investigated the effect of VPA on all three types of SWDs in children and adolescents with IGE. METHODS: Routine electroencephalography (EEG) during wakefulness, which was recorded before VPA monotherapy and up to four times during the first year of the VPA treatment, was analyzed retrospectively. For the analysis of the VPA effect on spontaneous SWDs and SWDs under hyperventilation, the number and duration of SWDs were counted. SWDs under intermittent photo stimulation (IPS) were classified according to the extent of propagation (grading). Response to VPA treatment (rest/hyperventilation) was defined as a disappearance of SWDs within the year after VPA introduction. KEY FINDINGS: Eighty-four patients (37 male and 47 female, mean age 9.5 ± 4.1 years) exhibited spontaneous SWDs or SWDs under hyperventilation. From this sample, 34 patients exhibited the PPR (7 male and 27 female, mean age 10.1 ± 3.9 years). A significant reduction in the number and duration of spontaneous SWDs and SWDs under hyperventilation was observed in the first 6 weeks of treatment (p ≤ 0.001, corrected, 87.3% responders). This effect remained stable over the 1 year observation period. Concerning PPR, only 4 (12.9%) of 31 patients were classified as responders. The difference between groups of patients with spontaneous/induced SWDs and PPR according to the number of responders was significant (p<0.001). SIGNIFICANCE: This study provides evidence that the effect of VPA on SWDs differs dependent on the types of SWDs. In the majority of patients, spontaneous SWDs and SWDs induced by hyperventilation disappeared, whereas the PPR mostly remained under VPA treatment. These results point to different pathogenetic mechanisms underlying the spontaneous and the evoked generalized epileptic activity in the EEG.

A retrospective study of the relation between vaccination and occurrence of seizures in Dravet syndrome.

Dravet syndrome is a severe epileptic encephalopathy starting in the first year of life. Mutations in SCN1A can be identified in the majority of patients, and epileptic seizures in the setting of fever are a clinical hallmark. Fever is also commonly seen after vaccinations and provocation of epileptic seizures by vaccinations in patients with Dravet syndrome has been reported, but not systematically assessed. In a retrospective evaluation of 70 patients with Dravet syndrome and SCN1A mutations, seizures following vaccinations were reported in 27%. In 58% of these patients vaccination-related seizures represented the first clinical manifestation. The majority of seizures occurred after DPT vaccinations and within 72 h after vaccination. Two-thirds of events occurred in the context of fever. Our findings highlight seizures after vaccinations as a common feature in Dravet syndrome and emphasize the need for preventive measures for seizures triggered by vaccination or fever in these children.

Serum concentrations of rufinamide in children and adults with epilepsy: the influence of dose, age, and comedication.

Rufinamide (RUF) is an orphan drug for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome in persons aged 4 years and older. Several studies have investigated the pharmaconkinetics of RUF, but information about interactions is still limited and the results are in part inconsistent. The aim of our study was to analyze the effect of age, gender, daily RUF dose per body weight (mg/kg), valproic acid (VPA), and enzyme-inducing antiepileptic drugs (EIAEDs) on RUF concentration-to-dose ratio (RUF serum concentration/RUF dose per body weight), RUF clearance (RUF dose/RUF serum concentration), and RUF trough concentrations. Different statistical methods were used to evaluate 292 blood samples from 119 patients who fulfilled the inclusion criteria. In summary, the results using generalized estimating equation regression models confirm a moderate but statistically significant nonlinear RUF concentration-dose relationship. At steady state, the trough concentrations of RUF increase in a less than dose proportional manner. Children (younger than 12 years) had significantly lower RUF concentrations (19.0%, P < 0.001) than adults (18 years or older) on comparable RUF doses per body weight. VPA was the most frequent comedication (51%) in our patient group. Mean RUF concentrations were 86.6% higher when VPA concentrations were greater than 90 µg/mL (P < 0.001) and 45.4% higher when VPA concentrations were between 50 and 90 µg/mL (P < 0.001) but not significantly different at VPA concentrations less than 50 µg/mL (4.4%, P > 0.1) compared with combinations without VPA. In combination with EIAEDs, mean RUF concentrations were 21.8% lower (P = 0.002) compared with combinations without EIAEDs. However, the group of AEDs classified as EIAEDs was heterogeneous and the number of patients, especially of children with EIAEDs, was relatively small. Our data indicate that oxcarbazepine and, especially, methsuximide decrease RUF concentrations as well. Therapeutic drug monitoring might be helpful because RUF concentrations differ markedly in patients on comparable RUF doses.

Neuronal networks in children with continuous spikes and waves during slow sleep.

Epileptic encephalopathy with continuous spikes and waves during slow sleep is an age-related disorder characterized by the presence of interictal epileptiform discharges during at least >85% of sleep and cognitive deficits associated with this electroencephalography pattern. The pathophysiological mechanisms of continuous spikes and waves during slow sleep and neuropsychological deficits associated with this condition are still poorly understood. Here, we investigated the haemodynamic changes associated with epileptic activity using simultaneous acquisitions of electroencephalography and functional magnetic resonance imaging in 12 children with symptomatic and cryptogenic continuous spikes and waves during slow sleep. We compared the results of magnetic resonance to electric source analysis carried out using a distributed linear inverse solution at two time points of the averaged epileptic spike. All patients demonstrated highly significant spike-related positive (activations) and negative (deactivations) blood oxygenation-level-dependent changes (P < 0.05, family-wise error corrected). The activations involved bilateral perisylvian region and cingulate gyrus in all cases, bilateral frontal cortex in five, bilateral parietal cortex in one and thalamus in five cases. Electrical source analysis demonstrated a similar involvement of the perisylvian brain regions in all patients, independent of the area of spike generation. The spike-related deactivations were found in structures of the default mode network (precuneus, parietal cortex and medial frontal cortex) in all patients and in caudate nucleus in four. Group analyses emphasized the described individual differences. Despite aetiological heterogeneity, patients with continuous spikes and waves during slow sleep were characterized by activation of the similar neuronal network: perisylvian region, insula and cingulate gyrus. Comparison with the electrical source analysis results suggests that the activations correspond to both initiation and propagation pathways. The deactivations in structures of the default mode network are consistent with the concept of epileptiform activity impacting on normal brain function by inducing repetitive interruptions of neurophysiological function.

Febrile infection-related epilepsy syndrome (FIRES): a nonencephalitic encephalopathy in childhood.

Encephalitis is generally presumed, even when seizures follow banal febrile infection, and pathogen detection in cerebrospinal fluid fails. This retrospective multicenter case series reports on 22 previously healthy children aged 3-15 years (median 6.5 years) with prolonged or recurrent seizures occurring 2-14 days (median 5 days) after fever onset (19 children with respiratory or nonspecific infections). Cerebrospinal fluid studies revealed 2-42 cells/microl (median 5 cells/microl) and no pathogens. Electroencephalography showed diffuse slowing or multifocal discharges. Neuroimaging demonstrated normal findings in 10 children. Brain biopsies were performed in seven children showing gliosis but no inflammation. Anesthetic barbiturates were used in 14 children with refractory status epilepticus, and immunotherapy in 9. Two children died, eight remained in a state of impaired consciousness, eight developed therapy-refractory epilepsies, two had behavioral disturbances, and two recovered. The lack of evidence for encephalitis suggests another infection-related pathogenesis of this disastrous epileptic encephalopathy. Therefore, we propose the term "febrile infection-related epilepsy syndrome" (FIRES).

Deletions in 16p13 including GRIN2A in patients with intellectual disability, various dysmorphic features, and seizure disorders of the rolandic region.

Seizure disorders of the rolandic region comprise a spectrum of different epilepsy syndromes ranging from benign rolandic epilepsy to more severe seizure disorders including atypical benign partial epilepsy/pseudo-Lennox syndrome,electrical status epilepticus during sleep, and Landau-Kleffner syndrome. Centrotemporal spikes are the unifying electroencephalographic hallmark of these benign focal epilepsies, indicating a pathophysiologic relationship between the various epilepsies arising from the rolandic region. The etiology of these epilepsies is elusive, but a genetic component is assumed given the heritability of the characteristic electrographic trait. Herein we report on three patients with intellectual disability, various dysmorphic features, and epilepsies involving the rolandic region, carrying previously undescribed deletions in 16p13. The only gene located in the critical region shared by all three patients is GRIN2A coding for the alpha-2 subunit of the neuronal N-methyl-D-aspartate(NMDA) receptor.

First European long-term experience with the orphan drug rufinamide in childhood-onset refractory epilepsy.

OBJECTIVE: Recently, we published the first postmarketing European experience with rufinamide (RUF) in a retrospective 12-week observational study. This follow-up report summarizes the long-term effectiveness and tolerability of RUF after 18 months for the same patient sample. METHODS: In total, 52 of 60 initially included patients from eight centers in Germany and Austria (45 children and 15 adults aged 1-50 years) with various severe and inadequately controlled epilepsy syndromes continued treatment with RUF after the initial 3-month observation period (mean final dose: 38.2+/-17.3mg/kg/day). Efficacy was assessed by seizure frequency evaluated by comparison with baseline frequency. Tolerability was evaluated by analysis of parental report of adverse events and laboratory tests. Responders were defined as patients who achieved a 50% or greater decrease in countable seizures within 18 months of initiating RUF therapy. RESULTS: Mean overall duration of RUF treatment was 14.5 months (range: 3-18 months). Retention rate, defined as the percentage of patients still taking RUF after 18 months, was 41.7% (n=25/60). The overall response rate after 18 months was 26.7% (16/60 patients). The highest response rates were found in the subgroup of patients with Lennox-Gastaut syndrome (LGS, 35.5%) and in patients with other generalized epilepsy syndromes. Complete seizure control was maintained in one patient (1.6%). A total of 73 adverse events were reported in 37 of 60 patients. The most frequently occurring adverse events were fatigue (18.3%), vomiting (15.0%), and loss of appetite (10.0%). Only 4 new adverse events were reported after week 12. No serious adverse events were observed. CONCLUSIONS: The present data suggest that RUF is efficacious and well tolerated in the long-term treatment of children and adults with various epilepsy syndromes and difficult-to-control seizures.

Hemodynamic changes preceding the interictal EEG spike in patients with focal epilepsy investigated using simultaneous EEG-fMRI.

EEG-fMRI is a non-invasive technique that allows the investigation of epileptogenic networks in patients with epilepsy. Lately, BOLD changes occurring before the spike were found in patients with generalized epilepsy. The study of metabolic changes preceding spikes might improve our knowledge of spike generation. We tested this hypothesis in patients with idiopathic and symptomatic focal epilepsy. Eleven consecutive patients were recorded at 3 T: five with idiopathic focal and 6 with symptomatic focal epilepsy. Thirteen spike types were analyzed separately. Statistical analysis was performed using the timing of spikes as events, modeled with HRFs peaking between -9 s and +9 s around the spike. HRFs were calculated the most focal BOLD response. Eleven of the thirteen studies showed prespike BOLD responses. Prespike responses were more focal than postspike responses. Three studies showed early positive followed by later negative BOLD responses in the spike field. Three had early positive BOLD responses in the spike field, which remained visible in the later maps. Three others had positive BOLD responses in the spike field, later propagating to surrounding areas. HRFs peaked between -5 and +6 s around the spike timing. No significant EEG changes could be identified prior to the spike. BOLD changes prior to the spike frequently occur in focal epilepsies. They are more focal than later BOLD changes and strongly related to the spike field. Early changes may result from increased neuronal activity in the spike field prior to the EEG spike and reflect an event more localized than the spike itself.

Combination of EEG-fMRI and EEG source analysis improves interpretation of spike-associated activation networks in paediatric pharmacoresistant focal epilepsies.

Simultaneous recording of EEG and functional MRI (EEG-fMRI) is a promising tool that may be applied in patients with epilepsy to investigate haemodynamic changes associated with interictal epileptiform discharges (IED). As the yield of the EEG-fMRI technique in children with epilepsy is still unclear, the aim of this study was to evaluate whether the combination of EEG-fMRI and EEG source analysis could improve localization of epileptogenic foci in children. Six children with an unambiguous focus localization were selected based on the criterion of the consistency of ictal EEG, PET and ictal SPECT. IEDs were taken as time series for fMRI analysis and as averaged sweeps for the EEG source analysis based on the distributed linear local autoregressive average (LAURA) solution. In four patients, the brain area with haemodymanic changes corresponded to the epileptogenic zone. However, additional distant regions with haemodynamic response were observed. Source analysis located the source of the initial epileptic activity in all cases in the presumed epileptogenic zone and revealed propagation in five cases. In three cases there was a good correspondence between haemodynamic changes and source localization at both the beginning and the propagation of IED. In the remaining three cases, at least one area of haemodynamic changes corresponded to either the beginning or the propagation. In most children analysed, EEG-fMRI revealed extended haemodynamic response, which were difficult to interpret without an appropriate reference, i.e. a priori hypothesis about epileptogenic zone. EEG source analysis may help to differentiate brain areas with haemodynamic response.

fMRI activation during spike and wave discharges evoked by photic stimulation.

Photoparoxysmal response (PPR) is an electroencephalographic (EEG) trait characterized by the occurrence of epileptiform discharges in response to visual stimulation. Studying this trait helps to learn about mechanisms of epileptogenicity. While simultaneous recordings of EEG and functional MRI (EEG-fMRI) in patients with spontaneous generalised spike-wave discharges (GSW) have revealed activation of the thalamus and deactivation in frontoparietal areas, EEG-fMRI studies on evoked GSW such as PPR are lacking. In this EEG-fMRI study, 30 subjects with reported generalised PPR underwent intermittent photic stimulation (IPS) in a 3 T MR scanner. PPR was elicited in 6 subjects, four diagnosed with idiopathic generalised epilepsy and two with tension-type headache. Because PPR is preceded by synchronization of cortical gamma oscillations, blood oxygenation level-dependent (BOLD) signal changes were analysed at the onset of the PPR (standard regressor) and 3 s before the onset of PPR (early regressor) in one model. In all subjects, IPS led to a significant activation of the visual cortex. Based on the early regressor, PPR associated activation was found in the parietal cortex adjacent to the intraparietal sulcus in five and in the premotor cortex in all 6 subjects. The standard regressor revealed deactivation in early activated areas in all subjects and thalamic activation in one subject. In contrast to spontaneous GSW, these results suggest that PPR is a cortical phenomenon with an involvement of the parietal and frontal cortices. Pronounced haemodynamic changes seen with the early regressor could mirror gamma activity that is known to precede PPR.

Effectiveness and tolerability of rufinamide in children and adults with refractory epilepsy: first European experience.

OBJECTIVE: The aim of the study was to explore the effectiveness and tolerability of rufinamide in a heterogeneous group of patients with refractory epilepsies in Europe, immediately after the drug became available as an orphan drug for the adjunctive treatment of Lennox-Gastaut syndrome (LGS). METHODS: This observational study was conducted as a collection of retrospective data from multiple centers in Germany and Austria. Clinical course in patients treated with rufinamide was documented. Initial dosage and titration schedule of rufinamide were at the discretion of the treating physician according to medical need. The observation period was 12 weeks. Effectiveness was evaluated by comparing the frequency of seizures with limitations to the countability between baseline and the last 4-week period of observation. RESULTS: The study population consisted of 45 children and 15 adults (mean age: 14.5+/-11.6 years, range: 1-50) with various severe and inadequately controlled epilepsy syndromes, that is, LGS (n=31), idiopathic generalized epilepsy syndromes (n=5), cryptogenic unclassified generalized epilepsy (n=7), and partial epilepsy (n=17). The response rate (50% reduction in countable seizures) was 46.7% (28 of 60 patients) in total; 25.0% experienced a 75% reduction in seizure frequency and 21.7% experienced a 50-75% reduction. Complete seizure control was achieved by 8.3%. The highest response rate was observed in patients with LGS (17/31, 54.8%), and the lowest in patients with partial epilepsy (4/17, 23.5%). Response rate in patients with unclassified generalized epilepsy was 42.8% (3/7 patients). A total of 67 adverse events were reported by 35 of 60 patients. The most frequently occurring adverse events were fatigue (18.3%), vomiting (13.3%), and loss of appetite (10.0%). No serious adverse events were observed. CONCLUSIONS: These preliminary data suggest that rufinamide may be effective and well tolerated in the treatment of children and adults with various epilepsy syndromes and difficult-to-control seizures. The results of our study suggest that the efficacy of rufinamide in patients with generalized epilepsy might be comparable to that in patients with LGS, whereas rufinamide was less effective in patients with partial epilepsy.