Epilepsy is a common neurologic disorder resulting in spontaneous, recurrent seizures. About 30–40% of patients are not responsive to pharmacologic therapies. This may be due to the differences between individual patients such as etiology, underlying pathophysiology, and seizure focus, and it highlights the importance of new drug discovery and testing in this field. Our goal was to determine the efficacy of lacosamide (LCM), a drug approved for the treatment of focal seizures, in a model of generalized epilepsy with cortical dysplasia (CD). We sought to compare LCM to levetiracetam (LEV), a drug that is currently used for the treatment of both partial and generalized epilepsy and to test its proficiency.Methods
Pregnant rats were irradiated to produce pups with malformed cortices in a model of CD, which will be referred to as the “first hit.” Adult animals, developed normally (NL) and irradiated (XRT), were surgically implanted with electroencephalography (EEG) electrodes. Baseline EEG was recorded on all rats prior to pretreatments with either LCM, LEV, or placebo (PBO). After 30 min, all rats were injected with a subconvulsive dose of pentylenetetrazole (PTZ), a γ-aminobutyric acid receptor A (GABAA) antagonist used to provoke generalized seizures as a “second hit.”Results
LCM and LEV were both effective against seizures induced by PTZ. XRT rats had a higher seizure incidence with longer and more severe seizures than NL rats. Seizure duration was decreased with both LCM and LEV in all animals. In XRT rats, there was a significant reduction in acute seizure incidence and severity with both LCM and LEV after PTZ injection.Significance
Our results suggest that LCM could be used as a potential treatment option for generalized epilepsy with CD as the underlying pathology.
MicroRNA and mesial temporal lobe epilepsy with hippocampal sclerosis: Whole miRNome profiling of human hippocampus
Mesial temporal lobe epilepsy (mTLE) is a severe neurological disorder characterized by recurrent seizures. mTLE is frequently accompanied by neurodegeneration in the hippocampus resulting in hippocampal sclerosis (HS), the most common morphological correlate of drug resistance in mTLE patients. Incomplete knowledge of pathological changes in mTLE+HS complicates its therapy. The pathological mechanism underlying mTLE+HS may involve abnormal gene expression regulation, including posttranscriptional networks involving microRNAs (miRNAs). miRNA expression deregulation has been reported in various disorders, including epilepsy. However, the miRNA profile of mTLE+HS is not completely known and needs to be addressed.Methods
Here, we have focused on hippocampal miRNA profiling in 33 mTLE+HS patients and nine postmortem controls to reveal abnormally expressed miRNAs. In this study, we significantly reduced technology-related bias (the most common source of false positivity in miRNA profiling data) by combining two different miRNA profiling methods, namely next generation sequencing and miRNA-specific quantitative real-time polymerase chain reaction.Results
These methods combined have identified and validated 20 miRNAs with altered expression in the human epileptic hippocampus; 19 miRNAs were up-regulated and one down-regulated in mTLE+HS patients. Nine of these miRNAs have not been previously associated with epilepsy, and 19 aberrantly expressed miRNAs potentially regulate the targets and pathways linked with epilepsy (such as potassium channels, γ-aminobutyric acid, neurotrophin signaling, and axon guidance).Significance
This study extends current knowledge of miRNA-mediated gene expression regulation in mTLE+HS by identifying miRNAs with altered expression in mTLE+HS, including nine novel abnormally expressed miRNAs and their putative targets. These observations further encourage the potential of microRNA-based biomarkers or therapies.
Lacosamide in the treatment of patients with epilepsy and intellectual disabilities: A long-term study of 136 patients
This study aimed to analyze the retention rate of lacosamide (LCM) in patients with epilepsy and intellectual disabilities (IDs), to identify factors influencing retention rate, and to investigate the LCM retention rate with and without concomitant sodium channel blocker (SCB). We hypothesized that the retention rate of LCM with concomitant SCB would be lower than without SCB.Methods
Using the Kaplan-Meier estimator, we conducted a monocentric, retrospective, observational, open-label study to evaluate LCM retention rates in patients with IDs and drug-resistant epilepsy. In addition, the impact of therapy-related variables on the long-term retention of LCM was evaluated.Results
One hundred thirty-six subjects with IDs and drug-resistant epilepsy were included (age 2–66 years); most patients had focal epilepsy. Long-term retention rates were 62.0% at 1 year, 43.7% at 2 years, and 29.1% at 3 and 4 years. Reasons for LCM discontinuation included insufficient therapeutic benefits (69%), adverse events (11%), or a combination of both factors (8%). The LCM retention rate was influenced by the number of background antiepileptic drugs (AEDs). An additional and independent influence of concomitant therapy with SCB on retention rate could not be confirmed.Significance
One of the major challenges in medically caring for patients with epilepsy and IDs is the high rate of drug resistance. However, there is a lack of evidence-based information about the efficacy and tolerability of AEDs in this population. It has been shown that concomitant SCB use is a key factor in increasing the risk of LCM failure in children with epilepsy. This finding has not been replicated in our predominantly adult sample of patients with IDs.
Epilepsy surgery of “low grade epilepsy associated neuroepithelial tumors”: A retrospective nationwide Italian study
To analyze the attitude and results of Italian epilepsy surgery centers in the surgical management of “low grade epilepsy associated neuroepithelial tumors” (LEATs).Methods
We conducted a retrospective study enrolling 339 consecutive patients with LEATs who underwent surgery between January 2009 and June 2015 at eight Italian epilepsy surgery centers. We compared demographic, clinical, pathologic, and surgical features of patients with favorable (Engel class I) and unfavorable (Engel class II, III, and IV) seizure outcome. In addition, we compared patients with tumor-associated focal cortical dysplasia (FCD) and patients with solitary tumors to identify factors correlated with FCD diagnosis.Results
Fifty-five (98.2%) of 56 patients with medically controlled epilepsy were seizure-free after surgery, compared to 249 (88.0%) of 283 patients with refractory epilepsy. At multivariate analysis, three variables independently predict unfavorable seizure outcome in the drug-resistant group. Age at surgery is largely the most significant (p = 0.001), with an odds ratio (OR) of 1.04. This means that the probability of seizure recurrence grows by 4% for every waited year. The resection site is also significant (p = 0.039), with a relative risk (RR) of 1.99 for extratemporal tumors. Finally, the completeness of tumor resection has a trend toward significance (p = 0.092), with an RR of 1.82 for incomplete resection. Among pediatric patients, a longer duration of epilepsy was significantly associated with preoperative neuropsychological deficits (p < 0.001). A statistically significant association was observed between FCD diagnosis and the following variables: tailored surgery (p < 0.001), temporal resection (p = 0.001), and surgical center (p = 0.012).Significance
Our nationwide LEATs study gives important insights on factors predicting seizure outcome in refractory epilepsy and determining variability in FCD detection. Timely surgery, regardless of pharmacoresistance and oriented to optimize epileptologic, neuropsychological, and oncologic outcomes should be warranted.
Cognitive functioning in children with self-limited epilepsy with centrotemporal spikes: A systematic review and meta-analysis
It is now well appreciated that benign epilepsy with centrotemporal spikes (BECTS, or more recently, ECTS) is associated with a range of cognitive and behavioral disturbances. Despite our improved understanding of cognitive functioning in ECTS, there have been to date no efforts to quantitatively synthesize the available literature within a comprehensive cognitive framework.Methods
The present systematic review and meta-analysis was conducted according to PRISMA guidelines. Forty-two case–control samples met eligibility criteria comprising a total of 1,237 children with ECTS and 1,137 healthy control children. Univariate, random-effects meta-analyses were conducted on eight cognitive factors in accordance with the Cattell–Horn–Carroll model of intelligence.Results
Overall, children with ECTS demonstrated significantly lower scores on neuropsychological tests across all cognitive factors compared to healthy controls. Observed effects ranged from 0.42 to 0.81 pooled standard deviation units, with the largest effect for long-term storage and retrieval and the smallest effect for visual processing.Significance
The results of the present meta-analysis provide the first clear evidence that children with ECTS display a profile of pervasive cognitive difficulties and thus challenge current conceptions of ECTS as a benign disease or of limited specific or localized cognitive effect.
The new epilepsy definition adopted by the International League Against Epilepsy (ILAE) includes patients with one unprovoked seizure with a probability of further seizures, similar to the general recurrence risk after two unprovoked seizures, occurring in a 10-year period. Long-term follow-up of patients diagnosed after a single seizure is needed to assess the applicability of the new epilepsy definition in clinical practice.Methods
Patients with newly diagnosed epilepsy were recruited retrospectively with a minimum follow-up of 10 years. Patients were stratified in two groups depending on the occurrence of one (new definition, ND) or two or more unprovoked seizures (traditional definition, TD) at the time of epilepsy diagnosis and compared for disease characteristics and factors predicting seizure recurrence. The primary outcome was the occurrence of a new unprovoked seizure during follow-up in the ND group. The secondary outcome was the achievement of an early remission in both groups.Results
Among 1,006 patients with newly diagnosed epilepsy, 152 (15.1%) were diagnosed after a single seizure. Compared to patients diagnosed using the TD, patients diagnosed according to the ND showed a higher proportion of subjects with an abnormal neurologic examination (19.9% vs. 13.7%, p = 0.0504) and with focal seizures (69.3% vs. 60.4%, p = 0.0021). The two samples differed in the presence of at least one of the factors predicting seizure recurrence (focal seizures or abnormal findings in at least one among the following: neurologic examination, electroencephalography [EEG], and neuroimaging) (94.6% vs. 89.1%, p = 0.0376). Long-term recurrence in patients diagnosed with the new definition was 83.6% at 10 years and 89.1% at 15 years. The probability of early remission did not differ between the two groups.Significance
Our results support the applicability of the new epilepsy definition in clinical practice. Individual patient characteristics and a personalized diagnostic approach can justify treatment after a single unprovoked seizure.
To identify potential pharmacokinetic interactions between the pharmaceutical formulation of cannabidiol (CBD; Epidiolex) and the commonly used antiepileptic drugs (AEDs) through an open-label safety study. Serum levels were monitored to identify interactions between CBD and AEDs.Methods
In 39 adults and 42 children, CBD dose was started at 5 mg/kg/day and increased every 2 weeks by 5 mg/kg/day up to a maximum of 50 mg/kg/day. Serum AED levels were obtained at baseline prior to CBD initiation and at most study visits. AED doses were adjusted if it was determined that a clinical symptom or laboratory result was related to a potential interaction. The Mixed Procedure was used to determine if there was a significant change in the serum level of each of the 19 AEDs with increasing CBD dose. AEDs with interactions seen in initial analysis were plotted for mean change in serum level over time. Subanalyses were performed to determine if the frequency of sedation in participants was related to the mean serum N-desmethylclobazam level, and if aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were different in participants taking concomitant valproate.Results
Increases in topiramate, rufinamide, and N-desmethylclobazam and decrease in clobazam (all p < 0.01) serum levels were seen with increasing CBD dose. Increases in serum levels of zonisamide (p = 0.02) and eslicarbazepine (p = 0.04) with increasing CBD dose were seen in adults. Except for clobazam and desmethylclobazam, all noted mean level changes were within the accepted therapeutic range. Sedation was more frequent with higher N-desmethylclobazam levels in adults (p = 0.02), and AST/ALT levels were significantly higher in participants taking concomitant valproate (p < 0.01).Significance
Significantly changed serum levels of clobazam, rufinamide, topiramate, zonisamide, and eslicarbazepine were seen. Abnormal liver function test results were noted in participants taking concomitant valproate. This study emphasizes the importance of monitoring serum AED levels and LFTs during treatment with CBD.
Specific changes in the functional connectivity of brain networks occur in patients with epilepsy. Yet whether such changes reflect a stable disease effect or one that is a function of active seizure burden remains unclear. Here, we longitudinally assessed the connectivity of canonical cognitive functional networks in patients with intractable temporal lobe epilepsy (TLE), both before and after patients underwent epilepsy surgery and achieved seizure freedom.Methods
Seventeen patients with intractable TLE who underwent epilepsy surgery with Engel class I outcome and 17 matched healthy controls took part in the study. The functional connectivity of a set of cognitive functional networks derived from typical cognitive tasks was assessed in patients, preoperatively and postoperatively, as well as in controls, using stringent methods of artifact reduction.Results
Preoperatively, functional networks in TLE patients differed significantly from healthy controls, with differences that largely, but not exclusively, involved the default mode and temporal/auditory subnetworks. However, undergoing epilepsy surgery and achieving seizure freedom did not lead to significant changes in network connectivity, with postoperative functional network abnormalities closely mirroring the preoperative state.Significance
This result argues for a stable chronic effect of the disease on brain connectivity, with changes that are largely “burned in” by the time a patient with intractable TLE undergoes epilepsy surgery, which typically occurs years after the initial diagnosis. The result has potential implications for the treatment of intractable epilepsy, suggesting that delaying surgical intervention that may achieve seizure freedom may lead to functional network changes that are no longer reversible by the time of epilepsy surgery.