Refractory Epilepsy: Clinical Overview

The Phosphodiesterase 10A Inhibitor PF-2545920 Enhances Hippocampal Excitability and Seizure Activity Involving the Upregulation of GluA1 and NR2A in Post-synaptic Densities

Phosphodiesterase regulates the homeostasis of cAMP and cGMP, which increase the strength of excitatory neural circuits and/or decrease inhibitory synaptic plasticity. Abnormally, synchronized synaptic transmission in the brain leads to seizures. A phosphodiesterase 10A (PDE10A) inhibitor PF-2545920 has recently attracted attention as a potential therapy for neurological and psychiatric disorders. We hypothesized that PF-2545920 plays an important role in status epilepticus (SE) and investigated the underlying mechanisms. PDE10A was primarily located in neurons, and PDE10A expression increased significantly in patients with temporal lobe epilepsy. PF-2545920 enhanced the hyperexcitability of pyramidal neurons in rat CA1, as measured by the frequency of action potentials and miniature excitatory post-synaptic current. GluA1 and NR2A expression also increased significantly in post-synaptic densities, with or without SE in rats treated with PF-2545920. The ratio of p-GluA1/GluA1 increased in the presence of PF-2545920 in groups with SE. Our results suggest that PF-2545920 facilitates seizure activity via the intracellular redistribution of GluA1 and NR2A in the hippocampus. The upregulation of p-GluA1 may play an important role in trafficking GluA1 to post-synaptic densities. The data suggest it would be detrimental to use the drug in seizure patients and might cause neuronal hyperexcitability in non-epileptic individuals.

Budget impact of perampanel as adjunctive treatment of uncontrolled partial-onset and primary generalized tonic-clonic seizures in the United States

PURPOSE

To evaluate the budget impact (BI) of adopting perampanel for adjunctive treatment of partial-onset seizures (POS), with or without secondarily generalized seizures, and the adjunctive treatment of primary generalized tonic-clonic seizures (PGTCS) in patients 12years or older in the United States.

METHODS

A BI model was developed to estimate the potential BI of adopting adjunctive perampanel from a US payer (direct costs only) and societal (direct and indirect costs) perspective over a 5-year period. Efficacy data for perampanel and antiepileptic drug (AED) maintenance therapy were obtained from perampanel phase III clinical trials. Drug, direct medical (healthcare provider, emergency room, and hospitalizations), and indirect (productivity loss) costs were obtained from appropriate sources (e.g., AnalySource® Online [wholesale acquisition costs], 2013 Optum Insight Clinformatics Database [market share percentages, direct medical costs per unit], and 2011-2013 National Health and Wellness Survey [NHWS; healthcare resource utilization, overall work impairment, and baseline distribution of patients across the 4 health states]). Mapping of seizure frequency to medical resource utilization and work impairment was obtained from Kantar Health's NHWS.

RESULTS

In a hypothetical health plan of 1 million members, 660 (0.066%) members ≥12years old had uncontrolled POS (395 [59.8%]) or PGTCS (265 [40.2%]). During the first 5years of adoption of perampanel, absolute BI (including drug, direct medical, and indirect costs) was $852, $2124, $3855, $5318, and $6397, respectively, for a cumulative absolute BI of $18,545. Drug cost was estimated to increase by $13,888, $34,646, $62,863, $86,728, and $104,326, respectively; however, this cost would be mostly offset by decreases in direct medical ($5041, $12,576, $22,818, $31,481, and $37,869, respectively) and indirect ($7995, $19,946, $36,190, $49,929, and $60,060, respectively) costs. Total per-member-per-month cost (drug and direct medical costs) was estimated to increase by $0.0007, $0.0018, $0.0033, $0.0046, and $0.0055 from years 1 to 5.

CONCLUSIONS

Based on results of this BI model, increased cost of adopting perampanel in a health plan of 1 million members would be minimal for payers, and societal costs would be close to neutral.

The epileptic amygdala: Toward the development of a neural prosthesis by temporally coded electrical stimulation

Many patients with epilepsy do not obtain proper control of their seizures through conventional treatment. We review aspects of the pathophysiology underlying epileptic phenomena, with a special interest in the role of the amygdala, stressing the importance of hypersynchronism in both ictogenesis and epileptogenesis. We then review experimental studies on electrical stimulation of mesiotemporal epileptogenic areas, the amygdala included, as a means to treat medically refractory epilepsy. Regular high-frequency stimulation (HFS) commonly has anticonvulsant effects and sparse antiepileptogenic properties. On the other hand, HFS is related to acute and long-term increases in excitability related to direct neuronal activation, long-term potentiation, and kindling, raising concerns regarding its safety and jeopardizing in-depth understanding of its mechanisms. In turn, the safer regular low-frequency stimulation (LFS) has a robust antiepileptogenic effect, but its pro- or anticonvulsant effect seems to vary at random among studies. As an alternative, studies by our group on the development and investigation of temporally unstructured electrical stimulation applied to the amygdala have shown that nonperiodic stimulation (NPS), which is a nonstandard form of LFS, is capable of suppressing both acute and chronic spontaneous seizures. We hypothesize two noncompetitive mechanisms for the therapeutic role of amygdala in NPS, 1) a direct desynchronization of epileptic circuitry in the forebrain and brainstem and 2) an indirect desynchronization/inhibition through nucleus accumbens activation. We conclude by reintroducing the idea that hypersynchronism, rather than hyperexcitability, may be the key for epileptic phenomena and epilepsy treatment.

Recurring Functional Interactions Predict Network Architecture of Interictal and Ictal States in Neocortical Epilepsy

Human epilepsy patients suffer from spontaneous seizures, which originate in brain regions that also subserve normal function. Prior studies demonstrate focal, neocortical epilepsy is associated with dysfunction, several hours before seizures. How does the epileptic network perpetuate dysfunction during baseline periods? To address this question, we developed an unsupervised machine learning technique to disentangle patterns of functional interactions between brain regions, or subgraphs, from dynamic functional networks constructed from approximately 100 h of intracranial recordings in each of 22 neocortical epilepsy patients. Using this approach, we found: (1) subgraphs from ictal (seizure) and interictal (baseline) epochs are topologically similar, (2) interictal subgraph topology and dynamics can predict brain regions that generate seizures, and (3) subgraphs undergo slower and more coordinated fluctuations during ictal epochs compared to interictal epochs. Our observations suggest that seizures mark a critical shift away from interictal states that is driven by changes in the dynamical expression of strongly interacting components of the epileptic network.

The effects of classic ketogenic diet on serum lipid profile in children with refractory seizures

More than 25 % of children with epilepsy develop refractory seizures unresponsive to both old and new generation anticonvulsants. Since such seizures have a serious negative impact on the quality of life, other treatment options are considered. The ketogenic diet is a well-known treatment for managing refractory seizures, although its mechanism of action is unknown. Studies have shown that this diet is as good as, or better than, any of the newer medications in reducing seizure frequency. However, concerns about adverse effects have been raised. We conducted an open label trial to show the effects of this diet on serum lipid profile. Thirty-three children with refractory epilepsy were treated with the ketogenic diet and were followed for 6 months. Their serum lipid profile was assessed at baseline, and at 3 and 6 months after initiating the diet. Seizure frequency was reduced in 63 % of children (no seizures in 2/33 and reduced >50 % in 19/33). However, after 6 months of administering the diet, median triglyceride was significantly increased (from 84 to 180 mg/dl, P < 0.001), median total cholesterol was significantly increased (from 180 to 285 mg/dl, P < 0.001), median serum low-density lipoprotein (LDL) was significantly increased (from 91 to 175 mg/dl, P < 0.001), and median serum high-density lipoprotein (HDL) was significantly increased (from 51 to 58 mg/dl, P < 0.001). Results of this study indicate that a classic ketogenic diet in children with refractory seizures is effective in seizure reduction, but leads to development of hypercholesterolemia and hypertriglyceridemia.

Patient-centered design criteria for wearable seizure detection devices

INTRODUCTION

Epilepsy is a common neurological condition. Seizure diary reports and patient- or caregiver-reported seizure counts are often inaccurate and underestimated. Many caregivers express stress and anxiety about the patient with epilepsy having seizures when they are not present. Therefore, a need exists for the ability to recognize and/or detect a seizure in the home setting. However, few studies have inquired on detection device features that are important to patients and their caregivers.

METHODS

A survey instrument utilizing a population of patients and caregivers was created to obtain information on the design criteria most desired for patients with epilepsy in regard to wearable devices.

RESULTS

One thousand one hundred sixty-eight responses were collected. Respondents thought that sensors for muscle signal (61.4%) and heart rate (58.0%) would be most helpful followed by the O₂ sensor (41.4%). There was more interest in these three sensor types than for an accelerometer (25.5%). There was very little interest in a microphone (8.9%), galvanic skin response sensor (8.0%), or a barometer (4.9%). Based on a rating scale of 1-5 with 5 being the most important, respondents felt that "detecting all seizures" (4.73) is the most important device feature followed by "text/email alerts" (4.53), "comfort" (4.46), and "battery life" (4.43) as an equally important group of features. Respondents felt that "not knowing device is for seizures" (2.60) and "multiple uses" (2.57) were equally the least important device features. Average ratings differed significantly across age groups for the following features: button, multiuse, not knowing device is for seizures, alarm, style, and text ability. The p-values were all<0.002. Eighty-two point five percent of respondents [95% confidence interval: 80.0%, 84.7%] were willing to pay more than $100 for a wearable seizure detection device, and 42.8% of respondents [95% confidence interval: 39.8%, 45.9%] were willing to pay more than $200.

CONCLUSIONS

Our survey results demonstrated that patients and caregivers have design features that are important to them in regard to a wearable seizure detection device. Overall, the ability to detect all seizures rated highest among respondents which continues to be an unmet need in the community with epilepsy in regard to seizure detection. Additional uses for a wearable were not as important. Based on our results, it is important that an alert (via test and/or email) for events be a portion of the system. A reasonable price point appears to be around $200 to $300. An accelerometer was less important to those surveyed when compared with the use of heart rate, oxygen saturation, or muscle twitches/signals. As further products become developed for use in other health arenas, it will be important to consider patient and caregiver desires in order to meet the need and address the gap in devices that currently exist.

Preventive and Abortive Strategies for Stimulation Based Control of Epilepsy: A Computational Model Study

Epilepsy is a condition in which periods of ongoing normal EEG activity alternate with periods of oscillatory behavior characteristic of epileptic seizures. The dynamics of the transitions between the two states are still unclear. Computational models provide a powerful tool to explore the underlying mechanisms of such transitions, with the purpose of eventually finding therapeutic interventions for this debilitating condition. In this study, the possibility to postpone seizures elicited by a decrease of inhibition is investigated by using external stimulation in a realistic bistable neuronal model consisting of two interconnected neuronal populations representing pyramidal cells and interneurons. In the simulations, seizures are induced by slowly decreasing the conductivity of GABA[Formula: see text] synaptic channels over time. Since the model is bistable, the system will change state from the initial steady state (SS) to the limit cycle (LS) state because of internal noise, when the inhibition falls below a certain threshold. Several state-independent stimulations paradigms are simulated. Their effectiveness is analyzed for various stimulation frequencies and intensities in combination with periodic and random stimulation sequences. The distributions of the time to first seizure in the presence of stimulation are compared with the situation without stimulation. In addition, stimulation protocols targeted to specific subsystems are applied with the objective of counteracting the baseline shift due to decreased inhibition in the system. Furthermore, an analytical model is used to investigate the effects of random noise. The relation between the strength of random noise stimulation, the control parameter of the system and the transitions between steady state and limit cycle are investigated. The study shows that it is possible to postpone epileptic activity by targeted stimulation in a realistic neuronal model featuring bistability and that it is possible to stop seizures by random noise in an analytical model.

A prospective study contrasting the psychiatric outcome in drug-resistant epilepsy between patients who underwent surgery and a control group

OBJECTIVE

Psychiatric morbidity in drug-resistant epilepsy is frequent and has a negative influence on quality of life. Surgery is proven to be the best therapeutic alternative for treating seizures. However, it is inconclusive with the current evidence whether surgery, per se, is a risk factor or promotes amelioration of psychiatric disorders. Until now, most studies have been cross-sectional with small or heterogeneous groups. In addition, the few prospective studies did not have an identical control group. The present study aims to clarify the role of surgery in psychopathologic alterations.

METHODS

We analyzed, through a prospective case-control study, the psychopathologic outcomes of patients with drug-resistant epilepsy, comparing those who underwent surgery and those who continued with pharmacologic treatment due to not being suitable for surgery. The assessments were performed during presurgical evaluation and 6 months after surgery. We studied psychiatric changes for each group, compared differences between groups, and also analyzed de novo and remission cases. Finally, we determined associated factors for postsurgical psychiatric disturbances.

RESULTS

The surgical group experienced a significant decrease in psychopathologic alterations in comparison with the control group. In addition, distress perception of surgical patients also improved, whereas it did not decrease in the control group. Patients who underwent surgery presented a decrease in depressive and anxiety symptoms, whereas the nonsurgical group increased its anxiety levels. De novo disturbances that appeared after surgery were less frequent than in nonsurgical patients. We observed significant favorable outcomes considering de novo versus remission cases for anxiety, depression, and total symptoms only in the surgical group. The two main predictors for psychiatric disorders after surgery were presurgical psychiatric functioning and surgery.

SIGNIFICANCE

Provides evidence that surgery improves psychiatric functioning in drug-resistant epilepsy through a prospective controlled study.

Thirty Years of Orphan Drug Legislation and the Development of Drugs to Treat Rare Seizure Conditions: A Cross Sectional Analysis

BACKGROUND

Epilepsy is a serious chronic health condition with a high morbidity impairing the life of patients and afflicted families. Many epileptic conditions, especially those affecting children, are rare disorders generating an urgent medical need for more efficacious therapy options. Therefore, we assessed the output of the US and European orphan drug legislations.

METHODS

Quantitative analysis of the FDA and EMA databases for orphan drug designations according to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) criteria.

RESULTS

Within the US Orphan Drug Act 40 designations were granted delivering nine approvals, i.e. clobazam, diazepam viscous solution for rectal administration, felbamate, fosphenytoin, lamotrigine, repository corticotropin, rufinamide, topiramate, and vigabatrin. Since 2000 the EMA granted six orphan drug designations whereof two compounds were approved, i.e. rufinamide and stiripentol. In the US, two orphan drug designations were withdrawn. Orphan drugs were approved for conditions including Lennox-Gastaut syndrome, infantile spasms, Dravet syndrome, and status epilepticus. Comparing time to approval for rufinamide, which was approved in the US and the EU to treat rare seizure conditions, the process seems faster in the EU (2.2 years) than in the US (4.3 years).

CONCLUSION

Orphan drug development in the US and in the EU delivered only few molecular entities to treat rare seizure disorders. The development programs focused on already approved antiepileptic drugs or alternative pharmaceutical formulations. Most orphan drugs approved in the US are not approved in the EU to treat rare seizures although some were introduced after 2000 when the EU adopted the Orphan Drug Regulation.

Glutamate imaging (GluCEST) lateralizes epileptic foci in nonlesional temporal lobe epilepsy

When neuroimaging reveals a brain lesion, drug-resistant epilepsy patients show better outcomes after resective surgery than do the one-third of drug-resistant epilepsy patients who have normal brain magnetic resonance imaging (MRI). We applied a glutamate imaging method, GluCEST (glutamate chemical exchange saturation transfer), to patients with nonlesional temporal lobe epilepsy based on conventional MRI. GluCEST correctly lateralized the temporal lobe seizure focus on visual and quantitative analyses in all patients. MR spectra, available for a subset of patients and controls, corroborated the GluCEST findings. Hippocampal volumes were not significantly different between hemispheres. GluCEST allowed high-resolution functional imaging of brain glutamate and has potential to identify the epileptic focus in patients previously deemed nonlesional. This method may lead to improved clinical outcomes for temporal lobe epilepsy as well as other localization-related epilepsies.

Elevated basal glutamate and unchanged glutamine and GABA in refractory epilepsy: Microdialysis study of 79 patients at the yale epilepsy surgery program

OBJECTIVE

Aberrant glutamate and γ-aminobutyric acid (GABA) neurotransmission contribute to seizure generation and the epileptic state. However, whether levels of these neurochemicals are abnormal in epileptic patients is unknown. Here, we report on interictal levels of glutamate, glutamine, and GABA in epilepsy patients at seizure onset and nonepileptic sites, cortical lesions, and from patients with poorly localized neocortical epilepsies.

METHODS

Subjects (n = 79) were medically refractory epilepsy patients undergoing intracranial electroencephalogram evaluation. Microdialysis probes (n = 125) coupled to depth electrodes were implanted within suspected seizure onset sites and microdialysis samples were obtained during interictal periods. Glutamate, glutamine, and GABA were measured using high-performance liquid chromatography. Probe locations were subsequently classified by consensus of expert epileptologists.

RESULTS

Glutamate levels were elevated in epileptogenic (p = 0.03; n = 7), nonlocalized (p < 0.001), and lesional cortical sites (p < 0.001) when compared to nonepileptogenic cortex. Glutamate was also elevated in epileptogenic (p < 0.001) compared to nonepileptogenic hippocampus. There were no statistical differences in GABA or glutamine, although GABA levels showed high variability across patients and groups.

INTERPRETATION

Our findings indicate that chronically elevated extracellular glutamate is a common pathological feature among epilepsies with different etiology. Contrary to our predictions, GABA and glutamine levels were not decreased in any of the measured areas. Whereas variability in GABA levels may in part be attributed to the use of GABAergic antiepileptic drugs, the stability in glutamine across patient groups indicate that extracellular glutamine levels are under tighter metabolic regulation than previously thought. Ann Neurol 2016;80:35-45.

Lentiviral Vector-Induced Overexpression of RGMa in the Hippocampus Suppresses Seizures and Mossy Fiber Sprouting

Repulsive guidance molecule a (RGMa) is a membrane-bound protein that inhibits axon outgrowth in the central nervous system. Temporal lobe epilepsy (TLE) is a common neurological disorder characterized by recurrent spontaneous seizures. To explore the role of RGMa in epilepsy, we investigated the expression of RGMa in patients with TLE, pilocarpine-induced rat model, and pentylenetetrazol kindling model of epilepsy, and then we performed behavioral, histological, and electrophysiological analysis by lentivirus-mediated overexpression of RGMa in the hippocampus of animal model. We found that RGMa was significantly decreased in TLE patients and in experimental rats from 6 h to 60 days after pilocarpine-induced seizures. In two types of epileptic animal models, pilocarpine-induced model and pentylenetetrazol kindling model, overexpression of RGMa in the hippocampus of rats exerted seizure-suppressant effects. The reduced spontaneous seizures were accompanied by attenuation of hippocampal mossy fiber sprouting. In addition, overexpression of RGMa inhibited hyperexcitability of hippocampal neurons via suppressing NMDAR-mediated currents in Mg²⁺-free-induced organotypic slice model. Collectively, these results demonstrate that overexpression of RGMa could be an alternative strategy for epilepsy therapy.

Ten Years after the International Committee of Medical Journal Editors' Clinical Trial Registration Initiative, One Quarter of Phase 3 Pediatric Epilepsy Clinical Trials Still Remain Unpublished: A Cross Sectional Analysis

INTRODUCTION

Although selective reporting of clinical trial results introduces bias into evidence based clinical decision making, publication bias in pediatric epilepsy is unknown today. Since there is a considerable ambiguity in the treatment of an important and common clinical problem, pediatric seizures, we assessed the public availability of results of phase 3 clinical trials that evaluated treatments of seizures in children and adolescents as a surrogate for the extent of publication bias in pediatric epilepsy.

METHODS

We determined the proportion of published and unpublished study results of phase 3 clinical trials that were registered as completed on ClinicalTrials.gov. We searched ClinicalTrials.gov, PubMed, and Google Scholar for publications and contacted principal investigators or sponsors. The analysis was performed according to STROBE criteria.

RESULTS

Considering studies that were completed before 2014 (N = 99), 75 (76%) pediatric phase 3 clinical trials were published but 24 (24%) remained unpublished. The unpublished studies concealed evidence from 4,437 patients. Mean time-to-publication was 25 SD ± 15.6 months, more than twice as long as mandated.

CONCLUSION

Ten years after the ICMJE's clinical trials registration initiative there is still a considerable amount of selective reporting and delay of publication that potentially distorts the body of evidence in the treatment of pediatric seizures.

Managing drug-resistant epilepsy: challenges and solutions

Despite the development of new antiepileptic drugs (AEDs), ~20%-30% of people with epilepsy remain refractory to treatment and are said to have drug-resistant epilepsy (DRE). This multifaceted condition comprises intractable seizures, neurobiochemical changes, cognitive decline, and psychosocial dysfunction. An ongoing challenge to both researchers and clinicians alike, DRE management is complicated by the heterogeneity among this patient group. The underlying mechanism of DRE is not completely understood. Many hypotheses exist, and relate to both the intrinsic characteristics of the particular epilepsy (associated syndrome/lesion, initial response to AED, and the number and type of seizures prior to diagnosis) and other pharmacological mechanisms of resistance. The four current hypotheses behind pharmacological resistance are the "transporter", "target", "network", and "intrinsic severity" hypotheses, and these are reviewed in this paper. Of equal challenge is managing patients with DRE, and this requires a multidisciplinary approach, involving physicians, surgeons, psychiatrists, neuropsychologists, pharmacists, dietitians, and specialist nurses. Attention to comorbid psychiatric and other diseases is paramount, given the higher prevalence in this cohort and associated poorer health outcomes. Treatment options need to consider the economic burden to the patient and the likelihood of AED compliance and tolerability. Most importantly, higher mortality rates, due to comorbidities, suicide, and sudden death, emphasize the importance of seizure control in reducing this risk. Overall, resective surgery offers the best rates of seizure control. It is not an option for all patients, and there is often a significant delay in referring to epilepsy surgery centers. Optimization of AEDs, identification and treatment of comorbidities, patient education to promote adherence to treatment, and avoidance of triggers should be periodically performed until further insights regarding causative pathology can guide better therapies.

Clinical Prediction Rule of Drug Resistant Epilepsy in Children

BACKGROUND AND PURPOSE

Clinical prediction rules (CPR) are clinical decision-making tools containing variables such as history, physical examination, diagnostic tests by developing scoring model from potential risk factors. This study is to establish clinical prediction scoring of drug-resistant epilepsy (DRE) in children using clinical manifestationa and only basic electroencephalography (EEG).

METHODS

Retrospective cohort study was conducted. A total of 308 children with diagnosed epilepsy were recruited. Primary outcome was the incidence of DRE. Independent determinants were patient characteristics, clinical manifestations and electroencephalography. CPR was performed based on multiple logistic regression.

RESULTS

The incidence of DRE was 42%. Risk factors were age onset, prior neurological deficits, and abnormal EEG. CPR can be established and stratified the prediction using scores into 3 levels such as low risk (score<6), moderate risk (score 6-12) and high risk (score>12) with positive likelihood ratio of 0.5, 1.8 and 12.5 respectively.

CONCLUSIONS

CPR with scoring risks were stratified into 3 levels. The strongest risk is prior global neurological deficits.

Prognostic factors of drug-resistant epilepsy in childhood: An Italian study

BACKGROUND

Epilepsy is drug resistant in 30-40% of cases. We studied, retrospectively, the prognostic factors of drug resistance (DR) during a 15 year period, in an Italian sample of patients with childhood epilepsy.

METHODS

A total of 117 patients were divided into two groups: one with DR, and the other without DR. The two groups were compared at the following time points: epilepsy onset (T0), and at 2, 5, 8 and 10 years after seizure onset (T2, T5, T8 and T10, respectively) using Fisher's exact test and randomization test. Multiple logistic regression analysis was then used to identify the most reliable predictive model of DR.

RESULTS

Positive neurological examination at onset, symptomatic/probable symptomatic etiology, lack of response to the first drug, seizure clustering during follow up, intelligence quotient ≤ 70, altered neuropsychological examination at onset, and presence of cerebral lesions were predominant in cases of DR. The most reliable combinations of predictors of DR included partial or no response to the first drug, presence of seizure clustering during follow up, altered neurological examination at onset, and long latency between epilepsy onset and first drug at T2; partial or absent response to the first drug and positive magnetic resonance imaging (MRI) at T5; positive MRI and absence of generalized seizures at T8; and positive MRI at T10. DR also sometimes appeared after discontinuation of an effective therapy.

CONCLUSIONS

Predictive factors of DR can be recognized in a large number of patients with epilepsy at disease onset, although the current possibility of predicting epilepsy outcome remains limited. In the long term, evidence of cerebral lesions appears to become the most significant prognostic factor.

Dynamic Network Drivers of Seizure Generation, Propagation and Termination in Human Neocortical Epilepsy

The epileptic network is characterized by pathologic, seizure-generating 'foci' embedded in a web of structural and functional connections. Clinically, seizure foci are considered optimal targets for surgery. However, poor surgical outcome suggests a complex relationship between foci and the surrounding network that drives seizure dynamics. We developed a novel technique to objectively track seizure states from dynamic functional networks constructed from intracranial recordings. Each dynamical state captures unique patterns of network connections that indicate synchronized and desynchronized hubs of neural populations. Our approach suggests that seizures are generated when synchronous relationships near foci work in tandem with rapidly changing desynchronous relationships from the surrounding epileptic network. As seizures progress, topographical and geometrical changes in network connectivity strengthen and tighten synchronous connectivity near foci-a mechanism that may aid seizure termination. Collectively, our observations implicate distributed cortical structures in seizure generation, propagation and termination, and may have practical significance in determining which circuits to modulate with implantable devices.

Increased Expression of Rac1 in Epilepsy Patients and Animal Models

The mechanisms of epilepsy remain incompletely understood. Rac1 (ras-related C3 botulinum toxin substrate 1) belongs to the Rho family of small GTPases. Rac1 play important roles in cytoskeleton rearrangement and neuronal synaptic plasticity, which had also been implicated in epilepsy. However, little is known regarding the expression of Rac1 in the epileptic brain or whether Rac1-targeted interventions affect the progression of epilepsy. The aim of this study was to investigate the expression profile of Rac1 in brain tissues from patients suffering from temporal lobe epilepsy (TLE) and experimental epileptic rats and determine the possible role of Rac1 in epilepsy. We demonstrated that the expression of Rac1 is significantly increased in TLE patients and in lithium-pilocarpine epilepsy model animals compared to the corresponding controls. Rac1 inhibitor NSC23766 reduced the severity of status epilepticus during the acute stage in a lithium-pilocarpine animal model. Consistent with these results, the latent period of a PTZ kindling animal model also increased. Our results demonstrated that the increased expression of Rac1 may contribute to pathophysiology of epilepsy.

The rise and fall of felbamate as a treatment for partial epilepsy--aplastic anemia and hepatic failure to blame?

Felbamate has been approved for refractory partial seizures since the early nineties. Due to safety concerns regarding its use, namely, in aplastic anemia and hepatic failure, felbamate's use has been restricted and a 'Black Box' warning has been inserted. Nonetheless, it is a useful drug in refractory cases of partial epilepsy. There are certain precautions which can prevent and minimize the serious idiosyncratic reactions associated with felbamate, thereby providing an option in refractory cases where no other drug works.

Dock3 Participate in Epileptogenesis Through rac1 Pathway in Animal Models

Epilepsy is one of the most common and severe neurologic diseases. The mechanisms of epilepsy are still not fully understood. Dock3 (dedicator of cytokinesis 3) is one of the new kinds of guanine-nucleotide exchange factors (GEF) and plays an important role in neuronal synaptic plasticity and cytoskeleton rearrangement; the same mechanisms were also found in epilepsy. However, little is known regarding the expression of Dock3 in the epileptic brain and whether Dock3 interventions affect the epileptic process. In this study, we showed that the expression of Dock3 significantly increased in IE patients and a lithium-pilocarpine epilepsy model compared with the controls. Inhibition of Dock3 by Dock3 shRNA impaired the severity of status epilepticus in the acute stage and decreased the spontaneous recurrent seizures times in the chronic stage of lithium-pilocarpine model and decreased the expression of rac1-GTP. Consistent with decreased expression of Dock3, the latent period in a pentylenetetrazole kindling model also increased. Our results demonstrated that the increased expression of Dock3 in the brain is associated with epileptogenesis and specific inhibition of Dock3 may be a potential target in preventing the development of epilepsy in patients.

Status epilepticus induction has prolonged effects on the efficacy of antiepileptic drugs in the 6-Hz seizure model

Several factors may influence the efficacy of antiepileptic drugs (AEDs) in patients with epilepsy, and treatment resistance could be related to genetics, neuronal network alterations, and modification of drug transporters or targets. Consequently, preclinical models used for the identification of potential new, more efficacious AEDs should reflect at least a few of these factors. Previous studies indicate that induction of status epilepticus (SE) may alter drug efficacy and that this effect could be long-lasting. In this context, we wanted to assess the protective effects of mechanistically diverse AEDs in mice subjected to pilocarpine-induced SE in another seizure model. We first determined seizure thresholds in mice subjected to pilocarpine-induced SE in the 6-Hz model, 2 weeks and 8 weeks following SE. We then evaluated the protective effects of mechanistically diverse AEDs in post-SE and control animals. No major differences in 6-Hz seizure susceptibility were observed between control groups, while the seizure threshold of pilocarpine mice at 8 weeks after SE was higher than at 2 weeks and higher than in control groups. Treatment with AEDs revealed major differences in drug response depending on their mechanism of action. Diazepam produced a dose-dependent protection against 6-Hz seizures in control and pilocarpine mice, both at 2 weeks and 8 weeks after SE, but with a more pronounced increase in potency in post-SE animals at 2 weeks. Levetiracetam induced a potent and dose-dependent protection in pilocarpine mice, 2 weeks after SE, while its protective effects were observed only at much higher doses in control mice. Its potency decreased in post-SE mice at 8 weeks and was very limited (30% protection at the highest tested dose) in the control group. Carbamazepine induced a dose-dependent protection at 2 weeks in control mice but only limited effect (50% at the highest tested dose) in pilocarpine mice. Its efficacy deeply decreased in post-SE mice at 8 weeks after SE. Perampanel and phenytoin showed almost comparable protective effects in all groups of mice. These experiments confirm that prior SE may have an impact on both potency and efficacy of AEDs and indicate that this effect may be dependent on the underlying epileptogenic processes. This article is part of a Special Issue entitled "Status Epilepticus".

MicroRNA-132 aggravates epileptiform discharges via suppression of BDNF/TrkB signaling in cultured hippocampal neurons

MicroRNAs (miRs) are increasingly recognized as targets to prevent or disrupt epilepsy as well as serve as diagnostic biomarkers of epileptogenesis. Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin related kinase type B (TrkB) also contribute to the pathophysiology of epilepsy. However, the possible involvement of miRs in BDNF-mediated molecular basis for epileptogenesis is less understood. In the present study, we found a dramatic upregulation of miR-132 and BDNF mRNA in the hippocampal neuronal culture model of status epilepticus (SE) obtained by Mg(2+)-free treatment. To investigate the role of miR-132 in the pathogenesis of epilepsy mediated by BDNF/TrkB signaling, we used a transfection approach to overexpress miR-132, and then detected a consequential decrease in BDNF mRNA and BDNF-dependent full-length TrkB receptor (TrkB.FL) signaling activity in the epileptic neurons. We investigated the alterations of epileptiform discharges in the hippocampal neuronal culture model of SE using the whole-cell patch-clamp technique. Activation of TrkB.FL by pretreatment with BDNF partly inhibited the Mg(2+)-free induced continuous high-frequency epileptiform discharges, while overexpression of miR-132 exacerbated epileptiform discharges. MiR-132 was also implicated in the postepileptic enhancement of high voltage dependent calcium channel. These results suggest that miR-132 promotes epileptogenesis through regulating BDNF/TrkB signaling in the hippocampal neuronal culture model of SE.

Health care charges for youth with newly diagnosed epilepsy

OBJECTIVES

To estimate first-year health care charges for youth with newly diagnosed epilepsy seen within an interdisciplinary pediatric epilepsy team and examine demographic, clinical, and psychosocial predictors of annual charges.

METHODS

Retrospective chart review was conducted to extract medical, hospital, and physician billing data from the year following an epilepsy diagnosis for 258 patients (aged 2-18 years) seen in a New Onset Seizure Clinic between July 2011 and December 2012. Descriptive statistics were used to estimate per-patient total first-year charges and health care utilization patterns (e.g., hospitalizations, emergency department visits, outpatient visits). Univariate analyses examined differences in health care charges between demographic, clinical, and psychosocial factors. Predictors of health care charges were examined using hierarchical multiple regression analysis.

RESULTS

The estimated per-patient total first-year health care charge was $20,084 (95% confidence interval [CI] $16,491-$23,677). Charges were higher for patients who reported having seizures since diagnosis ($25,509; 95% CI $20,162-$30,856) and were associated with more antiepileptic drug side effects (r = 0.18; 95% CI 0.03-0.32). Controlling for demographic and clinical factors, poorer baseline health-related quality of life was associated with higher per-patient health care charges (B = -445.40; 95% CI -865 to -25).

CONCLUSIONS

The economic impact of pediatric epilepsy in the year following diagnosis is substantial. Cost reduction efforts would be optimized by improving seizure control and targeting health-related quality of life, an outcome amenable to behavioral intervention.

Evaluation of the Effects of Charged Amino Acids on Uncontrolled Seizures

Introduction. Epilepsy is one of the most common diseases of the central nervous system. The prevalence of epilepsy throughout the world is 0.5 to 1%, and the same rate is 7.8 per 1000 in Kerman. Almost 20 to 30% of epileptic patients do not respond properly to common medications. The present study investigated patients who did not respond to common and, even in some cases, adjuvant therapies, with two seizures or more per week, regardless of the type of the inflicted epilepsy. Methodology. The participants of the present double-blind study were randomly selected into three 10-member groups of uncontrolled epileptic patients (arginine, glutamic acid, and lysine). The patients used amino acid powder dissolved in water (three times the daily need) every day for two weeks before breakfast. The number of seizures was recorded one week prior to commencing amino acid use, as well as the first and the second weeks subsequent to use. Results. A total of 32 patients were studied in three groups. The decline rates of seizures were 53%, 41%, and 13%, and the P value was 0.013, 0.027, and 0.720, respectively. Conclusion. Administration of the charged amino acids, arginine, and glutamic acid can decrease the seizures of patients suffering from uncontrolled epilepsy.

Management of epilepsy in patients with Rett syndrome: perspectives and considerations

Rett syndrome (RTT) is a common neurodevelopmental disorder that appears in infancy with regression of acquired motor skills, loss of purposeful activity, hand stereotypies, loss of acquired spoken language, and seizures. Epilepsy affects the majority of patients in a specific clinical stage of the disease and is drug resistant in approximately one-third of cases. The association of epilepsy and even drug-resistant epilepsy has been reported in certain genotypes of the methyl-CpG-binding protein 2 mutation, which is present in a majority of patients with classical RTT. The evolution of electroencephalographic abnormalities accompanying the clinical development of the syndrome is well described, but much less is known about the seizure semiology and the effectiveness of specific antiepileptic drugs. The aim of this review is to present the clinical and electrophysiological aspects of epilepsy in RTT and the current treatment approach.

Effects of JIP3 on epileptic seizures: Evidence from temporal lobe epilepsy patients, kainic-induced acute seizures and pentylenetetrazole-induced kindled seizures

JNK-interacting protein 3 (JIP3), also known as JNK stress-activated protein kinase-associated protein 1 (JSAP1), is a scaffold protein mainly involved in the regulation of the pro-apoptotic signaling cascade mediated by c-Jun N-terminal kinase (JNK). Overexpression of JIP3 in neurons in vitro has been reported to lead to accelerated activation of JNK and enhanced apoptosis response to cellular stress. However, the occurrence and the functional significance of stress-induced modulations of JIP3 levels in vivo remain elusive. In this study, we investigated the expression of JIP3 in temporal lobe epilepsy (TLE) and in a kainic acid (KA)-induced mouse model of epileptic seizures, and determined whether down-regulation of JIP3 can decrease susceptibility to seizures and neuron damage induced by KA. We found that JIP3 was markedly increased in TLE patients and a mouse model of epileptic seizures; mice underexpressing JIP3 through lentivirus bearing LV-Letm1-RNAi showed decreased susceptibility, delayed first seizure and decreased seizure duration response to the epileptogenic properties of KA. Subsequently, a decreased activation of JNK following seizure induction was observed in mice underexpressing JIP3, which also exhibited less neuronal apoptosis in the CA3 region of the hippocampus, as assessed three days after KA administration. We also found that mice underexpressing JIP3 exhibited a delayed pentylenetetrazole (PTZ)-induced kindling seizure process.

Direct nose-to-brain delivery of lamotrigine following intranasal administration to mice

Pharmacoresistance is considered one of the major causes underlying the failure of the anticonvulsant therapy, demanding the development of alternative and more effective therapeutic approaches. Due to the particular anatomical features of the nasal cavity, intranasal administration has been explored as a means of preferential drug delivery to the brain. The purpose of the present study was to assess the pharmacokinetics of lamotrigine administered by the intranasal route to mice, and to investigate whether a direct transport of the drug from nose to brain could be involved. The high bioavailability achieved for intranasally administered lamotrigine (116.5%) underscored the fact that a substantial fraction of the drug has been absorbed to the systemic circulation. Nonetheless, the heterogeneous biodistribution of lamotrigine in different brain regions, with higher concentration levels attained in the olfactory bulb comparatively to the frontal cortex and the remaining portion of the brain, strongly suggest that lamotrigine was directly transferred to the brain via the olfactory neuronal pathway, circumventing the blood-brain barrier. Therefore, it seems that intranasal route can be assumed as a suitable and valuable drug delivery strategy for the chronic treatment of epilepsy, also providing a promising alternative approach for a prospective management of pharmacoresistance.

Adjunctive brivaracetam for patients with refractory partial seizures: A meta-analysis of randomized placebo-controlled trials

OBJECTIVE

To evaluate the clinical efficacy and safety of the newer antiepileptic drug (AED), brivaracetam (BRV), as adjunctive therapy for adults with refractory partial seizures.

METHODS

Randomized-controlled trials (RCTs) of BRV in the treatment of refractory partial seizure were systematically reviewed and quantified using fixed- or random-effects meta-analysis. 50% responder rate, seizure free rate and adverse events in the treatment period were analyzed as outcomes for measuring efficacy and safety. Pooled effects of risk ratio (RR) and 95% confidence interval (CI) were derived from meta-analysis implemented in RevMan 5.2.

RESULTS

Five RCTs were identified for inclusion, and included a total of 1639 patients. The pooled RR of BRV vs. placebo as adjunctive therapy for adults with refractory partial seizure was 1.80 (95% CI 1.43-2.26, P < 0.00001) for 50% responder rates, 4.11 (95% CI 1.39-12.21, P = 0.01) for seizure free rates, 1.08 (95% CI 0.73-1.59; P = 0.70) for withdrawal rates. There was no evidence of a statistically significant association between the use of BRV and most adverse events, except somnolence (RR 1.63, 95% CI 1.08-2.45, P = 0.02) and fatigue (RR 2.05, 95% CI 1.19-3.53, P = 0.009).

CONCLUSION

This study confirmed significant effects of BRV as adjunctive treatment of refractory partial seizures. This study also demonstrated the good tolerability profile of adjunctive BRV for patients with epilepsy. Further large clinical and pharmacovigilance studies are needed to investigate the long-term efficacy and safety of BRV and, furthermore, to suggest an optimal BRV dosage for clinical use.

Perampanel efficacy and tolerability with enzyme-inducing AEDs in patients with epilepsy

OBJECTIVE

Evaluate the impact of concomitant enzyme (CYP3A4)-inducer antiepileptic drugs (EIAEDs) on the efficacy and safety of perampanel in patients from the 3 phase-III clinical trials.

METHODS

Patients with pharmacoresistant partial-onset seizures in the 3 phase-III clinical studies were aged 12 years and older and receiving 1 to 3 concomitant antiepileptic drugs. Following 6-week baseline, patients were randomized to once-daily, double-blind treatment with placebo or perampanel 8 or 12 mg (studies 304 and 305) or placebo or perampanel 2, 4, or 8 mg (study 306).

RESULTS

Treatment response assessed by median percent reduction in seizure frequency and responder rates improved with perampanel compared with placebo. However, at 8 and 12 mg, the treatment response was significantly greater in patients receiving non-EIAEDs. The treatment effect (perampanel-placebo) also demonstrated a dose-dependent increase in all patients. The overall incidence of treatment-emergent adverse events was similar regardless of the presence of EIAEDs. Occurrence of some adverse events, such as fatigue, somnolence, dizziness, irritability, was greater in patients receiving non-EIAEDs, as was discontinuation because of adverse events.

CONCLUSIONS

Perampanel shows efficacy and safety in the presence and absence of EIAEDs. As systemic exposure to perampanel increases, so does efficacy. Given the extensive metabolism of perampanel, systemic exposure is clearly reduced with concomitant administration of CYP3A4 inducers. This supports the strategy of dosing perampanel to clinical effect. Recognition of these pharmacokinetic interactions will be important in the optimization of this novel medication.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that 2 to 12 mg/d doses of perampanel reduced seizure frequency and improved responder rate in the presence and absence of EIAEDs.

Catamenial epilepsy: Update on prevalence, pathophysiology and treatment from the findings of the NIH Progesterone Treatment Trial

PURPOSE

To extend our knowledge and practical application of the concept of catamenial epilepsy.

METHODS

The review focuses on the impact of the NIH Progesterone Trial on our understanding of the pathophysiology and treatment of catamenial epilepsy.

RESULTS

Catamenial epilepsy refers to the cyclic exacerbation of seizures in relation to the menstrual cycle. An interaction between seizures and the menstrual cycle is suggested by variations in seizure frequency according to the day, phase and ovulatory status of the menstrual cycle. There are three commonly recognized patterns: perimenstrual (C1: Day -3 to +3), peri-ovulatory (C2: Day 10 to 3) and entire luteal phase in anovulatory cycles (C3: Day 10 to 3). Pathophysiological determinants include 1) the neuroactive properties of reproductive steroids, 2) the variation of neuroactive steroid levels across the menstrual cycle and 3) the differential susceptibility of epileptic substrates to neuroactive steroid effects. Perimenstrual seizure exacerbation may result from the premenstrual withdrawal of progesterone which is accompanied by withdrawal of allopregnanolone, a potent positive allosteric modulator of the GABAA receptor, and changes in the subunit composition of the GABAA receptor to the α4 subtype which is insensitive to benzodiazepine and GABA. Bioidentical progesterone supplement is no better than placebo in the treatment of women with focal onset epilepsy overall but shows superior efficacy in women whose seizures show robust perimenstrual exacerbation.

CONCLUSION

There is sound evidence for the existence of catamenial epilepsy and class 3 evidence for adjunctive progesterone treatment of the perimenstrually exacerbated subtype.

New antiepileptic medication linked to blue discoloration of the skin and eyes

Ezogabine is an antiepileptic medication approved in June 2011 by the US Food and Drug Administration (FDA) as an adjunctive treatment for partial seizures. Minimal drug interactions and a novel mechanism of action made ezogabine an appealing new treatment option. However, adverse effects reported during clinical trials and following drug approval have been alarming. A Risk Evaluation Mitigation Strategy (REMS) program has been established for urinary retention. A safety alert was published in April 2013 warning ezogabine may cause retinal pigment abnormalities and/or blue-gray discoloration, most notably on or near the lips, nail beds, sclera and conjunctiva with long-term use. In October 2013, the FDA announced a formal label change to ezogabine to include a black boxed warning emphasizing the previously reported warnings of eye and skin discoloration and permanent vision changes. Given the unknown nature of the pathophysiology, consequences and potential for reversibility of these effects, GlaxoSmithKline and the FDA have published recommendations for patients currently receiving ezogabine. Further data from published case reports and long-term safety trials in the future may lend additional insight into these concerning effects.

Clinical outcomes and quality of life following surgical treatment for refractory epilepsy: a systematic review and meta-analysis

Surgery for refractory epilepsy is widely used but the efficacy of this treatment for providing a seizure-free outcome and better quality of life remains unclear.This study aimed to update current evidence and to evaluate the effects of surgery on quality of life in patients with refractory epilepsy.A systematic review and meta-analysis of the literature were conducted and selected studies included 2 groups of refractory epilepsy patients, surgical and nonsurgical.The studies were assessed using the Newcastle-Ottawa Scale. The primary outcome was the seizure-free rate. The secondary outcome was quality of life. Adverse events were also reviewed.After screening, a total of 20 studies were selected: 8 were interventional, including 2 randomized controlled trials, and 12 were observational. All of the studies comprised 1959 patients with refractory epilepsy. The seizure-free rates were significantly higher for patients who received surgery compared with the patients who did not; the combined odds ratio was 19.35 (95% CI = 12.10-30.95, P < 0.001). After adjusting for publication bias the combined odds ratio was 10.25 (95% CI = 5.84-18.00). In both the interventional and observational studies, patients treated surgically had a significantly better quality of life compared with the patients not treated surgically. Complications were listed in 3 studies and the rates were similar in surgical and nonsurgical patients.Our meta-analysis found that for patients with refractory epilepsy, surgical treatment appears to provide a much greater likelihood of seizure-free outcome than nonsurgical treatment, although there is a need for more studies, particularly randomized studies, to confirm this conclusion. Based on more limited data, surgical treatment also appeared to provide a better quality of life and did not seem to increase complications.

Elevated Expression of Acid-Sensing Ion Channel 3 Inhibits Epilepsy via Activation of Interneurons

Recent studies have indicated that acid-sensing ion channels may play a significant role in the termination of epilepsy. In particular, acid-sensing ion channel 3 (ASIC3) is expressed in the central nervous system and is most sensitive to extracellular pH. However, whether ASIC3 plays a role in epilepsy is unknown. In this study, qRT-PCR, Western blot, immunohistochemistry, double immunofluorescence labeling, and slice recordings were used. We first detected elevated ASIC3 expression patterns in the brains of temporal lobe epilepsy patients and epileptic rats. ASIC3 was expressed in neurons and glia in both humans and in an experimental model of epilepsy, and ASIC3 was colocalized with inhibitory GABAergic interneurons. By blocking ASIC3 with its antagonist APETx2, we observed that injected APETx2 shortened the latency to seizure and increased the incidence of generalized tonic clonic seizure compared to the control group in models of both pilocarpine- and pentylenetetrazole (PTZ)-induced seizures. Additionally, blocking ASIC3 significantly decreased the frequency of action potential (AP) firing in interneurons. Moreover, APETx2 significantly reduced the amplitudes and frequencies of miniature inhibitory postsynaptic currents (mIPSCs) while showed no differences with the APETx2 + bicuculline group and the bicuculline group. These findings suggest that elevated levels of ASIC3 may serve as an anti-epileptic mechanism via postsynaptic mechanisms in interneurons. It could represent a novel therapeutic strategy for epilepsy treatment.

Synthesis of new perhydropyrrolo[1,2-a]pyrazine derivatives and their evaluation in animal models of epilepsy

A series of novel stereochemically pure derivatives of the investigative broad-spectrum anticonvulsant ADD408003 was designed and synthesized. Five-center four-component (U-5C-4CR) and four-center three-component (U-4C-3CR) variants of Ugi reaction were used in the key step of the synthetic pathways. The compounds obtained were evaluated for the anticonvulsant activitiy in the maximal electroshock seizure (MES), subcutaneous Metrazole (scMET) and minimal clonic seizure (6 Hz) animal models of epilepsy. The efficacies of most derivatives in the 6 Hz model of pharmacoresistant partial seizures were markedly higher than in the ‘classical’ MES and scMET models. The most active compounds, (4R,8aR)-3a, and (4S,8aS)-6 displayed median effective doses (ED₅₀) of 47.90 and 126.19 mg/kg, respectively, for the 6 Hz test.

Non-pharmacologic management of epilepsy

Non pharmacological treatment, in addition to pharmacological treatment is indicated in patients with refractory/pharmacoresistant epilepsy and includes ketogenic diet, deep brain stimulator, vagal nerve stimulator, transcranial magnetic stimulation and epilepsy surgery. Ketogenic diet has been recommended since 1921 and has been proved to be a safe and effective treatment for intractable epilepsy. Deep brain stimulator, has been used in the treatment of movement disorders for many years and recently been tried in the treatment of pharmacoresistant epilepsy. Vagus nerve stimulator is increasingly being used as an effective seizure aborting technique in patients not responding to anticonvulsants. Transcranial magnetic stimulation is a noninvasive brain stimulation technique which is being increasingly researched for use in patients with medication-refractory seizures who are not suitable candidates for surgery. Evolution of epilepsy surgery including Vagal nerve stimulator and Deep brain stimulator, as a successful treatment modality for intractable epilepsy has been influenced over the last decade by substantial advancement in imaging and operative/device related technology. The current article reviews the indications, mechanism of action, technological aspects and efficacy of the aforementioned modalities in the treatment of intractable/pharmacoresistant epilepsy in pediatric age group.