Histopathology of new-onset refractory status epilepticus (NORSE) in adults.

OBJECTIVE: new-onset refractory status epilepticus (NORSE) is defined as de novo refractory seizures occurring in previously healthy adults, without a clear underlying etiology. Due to refractory seizures and insufficient understanding of pathophysiology, management of these patients remains challenging and often leads to poor clinical outcomes. Various infectious and autoimmune mechanisms have been proposed but have not been validated and a large number of patients are thus labeled 'cryptogenic'. Moreover, histopathological findings have rarely been described in NORSE and are usually autopsy evaluations. In this paper, we describe the clinical correlates and histopathological findings in patients presenting with NORSE. METHODS: A case series of five patients with NORSE who underwent neurosurgical intervention and had histopathological examination during their acute clinical course. RESULTS: In all patients,status epileptics was refractory to treatment with antiseizure drugs (ASDs) and anesthetic agents. Autoimmune work-up revealed elevated titer of anti-GAD antibody in one patient but was unremarkable in others. Empiric use of immunomodulation therapy in three patients did not lead to cessation of status epilepticus (SE). Due to failure of prolonged medical management, three patients underwent palliative surgery for resection of epileptogenic tissue whereas the other two had diagnostic brain biopsy. Histopathology obtained during biopsy revealed evidence of vasculitis in one and necrotizing vasculopathy in another. The patient with anti-GAD antibodies had evidence of lymphocytic infiltration in limbic structures. The remaining two had nonspecific histopathological findings. SIGNIFICANCE: Although our findings are limited by a small number of patients, it adds to the growing premise of NORSE being related to an underlying autoimmune process. Additional studies, especially with histopathological data are needed to better understand this devastating disorder.

Frontal lobe hypometabolism associated with Sudden Unexpected Death in Epilepsy (SUDEP) risk: An objective PET study.

OBJECTIVE: Abnormalities of brain structures and neuronal networks have been identified in MRI studies of patients with Sudden Unexpected Death in Epilepsy (SUDEP) as well as in those at elevated risk. The goal of this study was to identify common patterns of objectively detected brain glucose metabolic abnormalities associated with SUDEP patients and those at high SUDEP risk. METHODS: Patients with refractory epilepsy (n = 78, age: 16-61 years, 44 females), who underwent comprehensive presurgical evaluation, were assessed for their risk of SUDEP using the revised SUDEP-7 inventory. From the 57 patients with low SUDEP risk, 35 were selected to match their demographic and clinical characteristics to those with high SUDEP risk (n = 21). [18F]fluoro-deoxy-glucose positron emission tomography (FDG-PET) abnormalities were evaluated in the high- and low-SUDEP risk subgroups compared to FDG-PET scans of a healthy adult control group using statistical parametric mapping (SPM). Individual FDG-PET scans of 4 additional patients, who died from SUDEP, were also analyzed by SPM. RESULTS: Mean SUDEP-7 score was 6.1 in the high and 2.7 in the low SUDEP risk group. MRI showed no lesion in 36 patients (64%). Statistical parametric mapping analysis of the high SUDEP risk subgroup showed bilateral medial frontal and inferior frontal hypometabolism as a common pattern. The low-risk group showed no specific common metabolic abnormalities on SPM group analysis. Individual PET scans of all 4 patients who died from SUDEP also showed bilateral frontal lobe hypometabolism. CONCLUSIONS: These data show that bilateral frontal lobe involvement on FDG-PET, especially the medial and inferior frontal cortex, may be a common metabolic pattern associated with high SUDEP risk and SUDEP itself, in patients with refractory focal epilepsy.

Atypical representation of sensorimotor cortex in a patient with autism and epilepsy confirmed by direct electrocortical stimulation.

Prior studies have used functional neuroimaging to demonstrate that the organization of the autistic brain is different from that of the non-autistic brain. Similarly, patients with epilepsy have also shown cortical reorganization. We present a case study that provides direct confirmation of disorganized sensorimotor distribution in a patient with autism spectrum disorder and epilepsy. To our knowledge, this is the first time cortical mapping directly showing abnormal cortical organization in a patient with autism spectrum disorder and epilepsy has been reported in the literature.

Racial variations in lacosamide serum concentrations in adult patients with epilepsy.

Lacosamide (LCM) is a third-generation anti-epileptic drug (AED) for partial-onset epilepsy with minimal hepatic metabolism and drug-drug interactions. The impact of individual patient variables such as race on drug metabolism have been under-reported in AEDs and LCM has not been specifically investigated. Our aim was to assess the role race plays on serum LCM levels in the management of epilepsy. Thus, we retrospectively reviewed patients with focal seizures who received LCM and had LCM levels as part of their routine clinical care in our Level IV Epilepsy Center. Variables including age, race, gender, LCM serum levels, LCM daily dose, and concomitant AEDs were collected and analyzed. A total of 93 patients with 1-3 clinic visits yielded 122 LCM serum levels. African Americans (AA) comprised 62.3% of our serum samples. Daily LCM doses averaged 350 mg/day (range 50-1000 mg/day). Eighty-nine percent of patients took 1-2 other AEDs. Overall, AA patients had lower LCM levels (mean 6.8 µg/mL) compared to White patients (mean of 7.1 µg/mL) (p = .017) even when considering for the daily dose effect (p = .007). Analysis of co-variables did not have significant effect on LCM levels. Overall, AA patients had a weaker relationship between LCM daily dose (adjusted for weight) and serum levels as compared to White patients and require a higher LCM dose per weight to achieve similar levels. Differences in pharmacogenetics may play an important role in these findings and focus on how these variations impact seizure burden.

Seizure-related injury and postictal aggression in refractory epilepsy patients.

OBJECTIVE: In the general population, injury related to seizures often involves falls, head trauma, soft tissue injuries, burns and fractures. Additionally, postictal deleterious behavior changes can by experienced by patients. We seek to identify the risk for seizure-related injury (SRI) and postictal aggression (PIA) in patients with refractory epilepsy. METHODS: Self-reported SRI and PIA were gathered through a seizure questionnaire as part of the epilepsy center's seizure safety protocol. Retrospective review of questionnaire, clinical course, and demographic data was completed. Statistical analysis of variables of interest was done using nonparametric methods. RESULTS: 126 patient questionnaires were completed over a one-year duration. Most patients reported seizure related injury (56.3 %) and postictal aggression (52.4 %). Increased disease duration was associated with seizure related injury and its severity (Kwallis p = 0.025), with number of antiepileptic drugs (AEDs) as significant factors (p = 0.012). Postictal aggression was also associated with a longer duration of epilepsy (Ranksum p = 0.037, t-test p = 0.04) and higher seizure frequency (p = 0.017). Patients who reported seizure related injury and postictal aggression were on more AEDs (p = 0.0003, p = 0.01, respectively), with first-generation AEDs being most contributory. CONCLUSION: The majority of patients with seizures report seizure-related injuries and postictal aggression. Duration and AED regimen are significant risk factors and screening practices can potentially guide safety measures and recommendations.

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

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

Intraoperative hippocampal electrocorticography frequently captures electrographic seizures and correlates with hippocampal pathology.

OBJECTIVE: Relationship between electrographic seizures on hippocampal electrocorticography (IH-ECoG) and presence/type of hippocampal pathology remains unclear. METHODS: IH-ECoG was recorded for 10-20 min from the ventricular surface of the hippocampus following removal of the temporal neocortex in 40 consecutive patients. Correlation between intraoperative hippocampal seizures and preoperative MRI, hippocampal histopathology, and EEG from invasive monitoring was determined. RESULTS: IH-ECoG captured electrographic seizures in 15/40 patients (in 8/23 with abnormal hippocampal signal on MRI and 7/17 patients without MRI abnormality). Hippocampal neuronal loss was observed in 22/40 (Group 1), while 18/40 had no significant neuronal loss (Group 2). In Group 1, 4/22 had seizures on IH-ECoG, while 11/18 had electrographic seizures in Group 2. In 24/40 patients who underwent prolonged extraoperative intracranial EEG (IC-EEG) recording, hippocampal seizures were captured in 14. Of these, 7 also had seizures during IH-ECoG. In 10/24 IC-EEG patients without seizures, 3 had seizures on IH-ECoG. CONCLUSIONS: IH-ECoG frequently captures spontaneous electrographic seizures. These are more likely to occur in patients with pathologic processes that do not disrupt/infiltrate hippocampus compared to patients with intractable epilepsy associated with disrupted hippocampal architecture. SIGNIFICANCE: Intraoperative hippocampal seizures may result from deafferentation from the temporal neocortex and disinhibition of the perforant pathway.

Acute Resective Surgery for the Treatment of Refractory Status Epilepticus.

BACKGROUND: To identify the role of acute surgical intervention in the treatment of refractory status epilepticus (RSE). METHODS: Retrospective review of consecutive patients who underwent epilepsy surgery from 2006 to 2015 was done to identify cases where acute surgical intervention was employed for the treatment of RSE. In addition, the adult and pediatric RSE literature was reviewed for reports of surgical treatment of RSE. RESULTS: Nine patients, aged 20-68 years, with various etiologies were identified to have undergone acute surgical resection for the treatment of RSE, aided by electrocorticography. Patients required aggressive medical therapy with antiepileptic drugs and intravenous anesthetic drugs for 10-54 days and underwent extensive neurodiagnostic testing prior to resective surgery. Eight out of nine patients survived and five patients were seizure-free at the last follow-up. The literature revealed 13 adult and 48 pediatric cases where adequate historical detail was available for review and comparison. CONCLUSIONS: We present the largest cohort of consecutive adult patients who underwent resective surgery in the setting of RSE. We also reveal that surgery can be efficacious in aborting status and in some can lead to long-term seizure freedom. Acute surgical intervention is a viable option in prolonged RSE and proper evaluation for such intervention should be conducted, although the timing and type of surgical intervention remain poorly defined.

Management of brain tumor-related epilepsy.

Seizures are common in both primary and metastatic brain tumors, although the rate of seizures differ significantly between the different types of neoplasms. Patients with brain tumor-associated seizures need treatment with antiepileptic drugs (AEDs) to prevent recurrence, whereas strong clinical data exists to discourage routine prophylaxis in patients who have not had seizures. The newer AEDs, such as levetiracetam, lamotrigine, lacosamide, topiramate, or pregabalin, are preferable for various reasons, primarily related to the side-effect profile and limited interactions with other drugs. If seizures persist despite initiation of an appropriate monotherapy (in up to 30-40% of cases), additional anticonvulsants may be necessary. Early surgical intervention improves seizure outcomes in individuals with medically refractory epilepsy, especially in patients with a single lesion that is epileptogenic. Data for this review article were compiled by searching for scholarly articles using the following keywords: brain tumor, epilepsy, seizure, tumor-related epilepsy, central nervous system, epidemiology, review, clinical trial, and surgery. Articles were screened for relevance by title and abstract, and selected for review and inclusion based on significant contribution to the topics discussed.

Effects of Marijuana on Ictal and Interictal EEG Activities in Idiopathic Generalized Epilepsy.

Marijuana-based treatment for refractory epilepsy shows promise in surveys, case series, and clinical trials. However, literature on their EEG effects is sparse. Our objective is to analyze the effect of marijuana on EEG in a 24-year-old patient with idiopathic generalized epilepsy treated with cannabis. We blindly reviewed 3 long-term EEGs-a 24-hour study while only on antiepileptic drugs, a 72-hour EEG with Cannabis indica smoked on days 1 and 3 in addition to antiepileptic drugs, and a 48-hour EEG with combination C indica/sativa smoked on day 1 plus antiepileptic drugs. Generalized spike-wave discharges and diffuse paroxysmal fast activity were categorized as interictal and ictal, based on duration of less than 10 seconds or greater, respectively. Data from three studies concatenated into contiguous time series, with usage of marijuana modeled as time-dependent discrete variable while interictal and ictal events constituted dependent variables. Analysis of variance as initial test for significance followed by time series analysis using Generalized Autoregressive Conditional Heteroscedasticity model was performed. Statistical significance for lower interictal events (analysis of variance P = 0.001) was seen during C indica use, but not for C indica/sativa mixture (P = 0.629) or ictal events (P = 0.087). However, time series analysis revealed a significant inverse correlation between marijuana use, with interictal (P < 0.0004) and ictal (P = 0.002) event rates. Using a novel approach to EEG data, we demonstrate a decrease in interictal and ictal electrographic events during marijuana use. Larger samples of patients and EEG, with standardized cannabinoid formulation and dosing, are needed to validate our findings.

Acute or chronic use of lacosamide does not alter its distribution between serum and cerebrospinal fluid.

OBJECTIVE: The site of action for antiepileptic drugs (AEDs) is within the brain; however, cerebrospinal fluid (CSF) concentration is highly variable. Lacosamide (LCM) is approved by the U.S. Food and Drug Administration (FDA) for treatment of partial-onset seizures in adults, and has linear pharmacokinetics in serum. Penetration across the blood-brain barrier (BBB) is unknown. This study aims to provide additional insights into the pharmacokinetics of LCM. METHODS: Thirty adults undergoing craniotomy for treatment of intractable epilepsy or brain tumor were recruited and were either taking LCM long term (group 1, n = 15), or were LCM naive, receiving LCM as prophylaxis for surgery (group 2, n = 15). All patients received one intravenous (IV) dose (15 min infusion) immediately prior to craniotomy. CSF and arterial blood were collected simultaneously following craniotomy. LCM concentrations were measured in serum and CSF. RESULTS: LCM concentration differences between groups 1 and 2 for both CSF and serum were statistically significant (p ≤ 0.0005), but there was no statistically significant difference in CSF/serum ratios (group 1 = 0.726 ± 0.231; group 2 = 0.556 ±0.241; p = 0.0585). LCM concentration in serum correlated positively with CSF concentration in group 1 (Pearson r = 0.8527, p < 0.0001). The time interval between the end of dose delivery and sample collection correlated positively with the CSF/serum ratio for the drug-naive group (Pearson r = 0.6525; p = 0.0084). Treatment with other AEDs did not affect LCM distribution between serum and CSF. SIGNIFICANCE: Although chronic dosing resulted in higher LCM concentrations in serum and CSF compared to drug-naive patients, the CSF/serum ratio was not affected by LCM pretreatment. These data suggest that LCM serum concentration may reliably predict CSF concentration.

Drug-induced EEG pattern predicts effectiveness of ketamine in treating refractory status epilepticus.

Refractory status epilepticus (RSE) can lack overt clinical manifestation and is usually treated with continuous infusion of intravenous anesthetic drugs (IVADs), where the use of continuous electroencephalography (cEEG) is imperative. Ketamine has recently been shown to be effective in the treatment of RSE. We retrospectively review a cohort of 11 patients receiving ketamine as part of their treatment regimen for RSE. We report on the presence of a characteristic EEG rhythm consisting of a generalized archiform theta to beta rhythms (7-20 Hz) appearing after ketamine administration. This pattern was seen in five patients, four of whom achieved successful resolution of RSE. Ketamine-induced EEG pattern may serve as a biomarker predictive of successful treatment outcome in RSE.

Evaluation of magnetic resonance imaging-negative drug-resistant epilepsy.

A structural brain lesion in patients with drug-resistant epilepsy (DRE) greatly increases the likelihood of identification of the seizure focus and ultimately seizure-free outcome following resective epilepsy surgery. In contrast, surgical outcomes of true non-lesional DRE are less favorable. Therefore, discovery of an underlying lesion is paramount in the pre-surgical work-up of patients with DRE. Over the years, the surgical treatment of pharmacoresistant epilepsy has evolved from straightforward lesional cases to include cases with hippocampal sclerosis. With the advent of magnetic resonance imaging (MRI), most cases of mesial temporal sclerosis became more easily identifiable on pre-operative neuroimaging. With the widespread use of high-resolution MRI with epilepsy protocols over the last two decades, our ability to visualize subtle structural changes has been greatly enhanced. However, there are some cases of lesional epilepsy, which remain unidentified on these routine MRIs. In such "non-lesional" refractory epilepsies, further investigation with advanced neuroimaging techniques, including metabolic imaging, as well as electrophysiological studies may help to identify the previously non-visualized focal brain abnormalities. In this review, we outline the current status for evaluation of MRI-negative DRE.

Invasive electroencephalography monitoring: Indications and presurgical planning.

Electroencephalography (EEG) remains a "gold standard" for defining seizures; hence identification of epileptogenic zone for surgical treatment of epilepsy requires precise electrographic localization of the seizures. Routine scalp EEG recording is not sufficient in many instances, such as extratemporal lobe epilepsy or non-lesional temporal lobe epilepsy. In these individuals EEG recording from proximity of the seizure focus is necessary, which can be achieved by placing electrodes on the surface or in the substance of the brain. As this process requires invasive procedures (usually necessitating surgical intervention) EEG obtained via these electrodes is defined as invasive electroencephalography (iEEG). As only limited areas of the brain can be covered by these electrodes in an individual, precise targeting of the presumed seizure onset location is crucial. The presurgical planning includes where to place electrodes, which type of the electrodes to choose and planned duration of the intracranial recording. Though there are general principles that guide such endeavor, each center does it slightly differently depending upon the various technologies available to them and expertise and preferences of the epilepsy surgery team. Here we describe our approach to iEEG recording. We briefly describe the background, types of iEEG recording and rationale for each, various electrode types, and scenarios where iEEG might be useful. We also describe planning of iEEG recording once the need has been established as well as our decision making process of deciding about location of electrode placement, type of electrodes to use, length of recording, choice of arrays, mapping of eloquent cortex and finally surgical planning and decisions.

Evaluating signal-correlated noise as a control task with language-related gamma activity on electrocorticography.

OBJECTIVE: Our recent electrocorticography (ECoG) study suggested reverse speech, a widely used control task, to be a poor control for non-language-related auditory activity. We hypothesized that this may be due to retained perception as a human voice. We report a follow-up ECoG study in which we contrast forward and reverse speech with a signal-correlated noise (SCN) control task that cannot be perceived as a human voice. METHODS: Ten patients were presented 90 audible stimuli, including 30 each of corresponding forward speech, reverse speech, and SCN trials, during ECoG recording with evaluation of gamma activity between 50 and 150 Hz. RESULTS: Sites of the lateral temporal gyri activated throughout speech stimuli were generally less activated by SCN, while some temporal sites seemed to process both human and non-human sounds. Reverse speech trials were associated with activities across the temporal lobe similar to those associated with forward speech. CONCLUSIONS: Findings herein externally validate functional neuroimaging studies utilizing SCN as a control for non-language-specific auditory function. Our findings are consistent with the notion that stimuli perceived as originating from a human voice are poor controls for non-language auditory function. SIGNIFICANCE: Our findings have implications in functional neuroimaging research as well as improved clinical mapping of auditory functions.

Systems biology of human epilepsy applied to patients with brain tumors.

Epilepsy is a disease of recurrent seizures that can be associated with a wide variety of acquired and developmental brain lesions. Current medications for patients with epilepsy can suppress seizures; they do not cure or modify the underlying disease process. On the other hand, surgical removal of focal brain regions that produce seizures can be curative. This surgical procedure can be more precise with the placement of intracranial recording electrodes to identify brain regions that generate seizure activity as well as those that are critical for normal brain function. The detail that goes into these surgeries includes extensive neuroimaging, electrophysiology, and clinical data. Combined with precisely localized tissues removed, these data provide an unparalleled opportunity to learn about the interrelationships of many "systems" in the human brain not possible in just about any other human brain disorder. Herein, we describe a systems biology approach developed to study patients who undergo brain surgery for epilepsy and how we have begun to apply these methods to patients whose seizures are associated with brain tumors. A central goal of this clinical and translational research program is to improve our understanding of epilepsy and brain tumors and to improve diagnosis and treatment outcomes of both.

Histopathological evidence that hippocampal atrophy following status epilepticus is a result of neuronal necrosis.

Medial temporal lobe epilepsy is commonly associated with hippocampal atrophy on MRI and hippocampal sclerosis on histopathological examination of surgically-resected specimens. Likewise, it is well-established that prolonged seizures and status epilepticus can lead to hippocampal edema as noted on MRI. In this paper, the authors present an unusual patient with prolonged refractory status epilepticus, due to limbic encephalitis associated with anti-GAD antibody, who underwent palliative epilepsy surgery. Bilateral hippocampal edema was noted on preoperative MRI. Histologic evaluation confirmed presence of acute necrosis and neuronal loss in the left hippocampal formation. Follow-up MRI several months after surgery demonstrated severe atrophy of the contralateral right hippocampus. This is the first clear histopathological evidence that hippocampal atrophy following status epilepticus is the result of acute neuronal necrosis and cell loss.