Seizure clusters and adverse events during pre-surgical video-EEG monitoring with a slow anti-epileptic drug (AED) taper

Epilepsy monitoring unit practices and safety among NAEC epilepsy centers: A census survey

OBJECTIVE

An epilepsy monitoring unit (EMU) is a specialized unit designed for capturing and characterizing seizures and other paroxysmal events with continuous video electroencephalography (vEEG). Nearly 260 epilepsy centers in the United States are accredited by the National Association of Epilepsy Centers (NAEC) based on adherence to specific clinical standards to improve epilepsy care, safety, and quality. This study examines EMU staffing, safety practices, and reported outcomes.

METHOD

We analyzed NAEC annual report data and results from a supplemental survey specific to EMU practices reported in 2019 from 341 pediatric or adult center directors. Data on staffing, resources, safety practices and complications were collated with epilepsy center characteristics. We summarized using frequency (percentage) for categorical variables and median (inter-quartile range) for continuous variables. We used chi-square or Fisher's exact tests to compare staff responsibilities.

RESULTS

The supplemental survey response rate was 100%. Spell classification (39%) and phase 1 testing (28%) were the most common goals of the 91,069 reported admissions. The goal ratio of EEG technologist to beds of 1:4 was the most common during the day (68%) and off-hours (43%). Compared to residents and fellows, advanced practice providers served more roles in the EMU at level 3 or pediatric-only centers. Status epilepticus (SE) was the most common reported complication (1.6% of admissions), while cardiac arrest occurred in 0.1% of admissions.

SIGNIFICANCE

EMU staffing and safety practices vary across US epilepsy centers. Reported complications in EMUs are rare but could be further reduced, such as with more effective treatment or prevention of SE. These findings have potential implications for improving EMU safety and quality care.

Predicting seizure clustering in the epilepsy monitoring unit: A multivariable analysis

INTRODUCTION

Seizure clustering, is the most frequently reported adverse event in epilepsy monitoring unit (EMU) safety studies which, can also potentiate other adverse events, such as falls, status epilepticus, and increased length of stay. The purpose of this study is to determine variables associated with increased risk of seizure clustering among patients admitted to the EMU.

METHODS

A retrospective review of patients admitted to the EMU over a two-year period was completed. Data collected included patient demographics, types of epilepsy, seizure frequency, anti-seizure medications (ASMs) and hospital and EMU course including incidence of seizure clustering.

RESULTS

Two hundred seven patients were included in our study; of these, ninety patients experienced two or more seizures in a 24-hour period (24SC), and 68 patients experienced two or more seizures in a 4-hour period (4SC). Logistic regression analysis associated the absence of long-acting ASM with increased clustering within the 4SC group (p = 0.038). For every additional ASM taken by a patient at home, the odds of seizure clustering increased by 81% in the 4SC group (p = 0.009) and by 61% in the 24SC group (p = 0.022). In addition, patients with a diagnosis of temporal lobe epilepsy had some association with clustering in the 24SC group (p = 0.061).

CONCLUSION

Our data showed that long-acting ASMs can be protective against seizure clustering. Furthermore, patients with temporal lobe epilepsy, and those on increased numbers of ASMs, were more likely to experience seizure clustering when undergoing medication withdrawal during an EMU evaluation.

Safety and efficacy of rapid withdrawal of anti-seizure medication during long-term video-EEG monitoring

Objective

Anti-seizure medications (ASMs) are often withdrawn during long-term video-EEG monitoring (LTM) to allow pre-surgical evaluation. Herein, we evaluated the safety and efficacy of ultra-rapid withdrawal (URW) and rapid withdrawal (RW) of ASMs in an epilepsy monitoring unit (EMU).

Methods

This retrospective study examined all consecutive patients admitted to our EMU between May 2021 and October 2022. Patients were classified into the URW and RW groups according to the way ASMs were withdrawn. We compared the efficacy and safety of the procedures used in the groups in terms of duration of LTM, latency to the first seizure, and incidence of focal to bilateral tonic-clonic seizures (FBTCS), seizure clusters (SC), and status epilepticus (SE).

Results

Overall, 110 patients (38 women) were included. The mean age of patients at the time of LTM was 29 years. All medications were stopped on admission for monitoring in the URW group (n = 75), while in the RW group (n = 35) ASMs were withdrawn within 1 day. In both groups, the duration of LTM was approximately 3 days: URW group (2.9 ± 0.5 days) and RW group (3.1 ± 0.8 days). The latency to the first seizure was significantly different between the two groups; however, there were no differences between the two groups in terms of the distribution of FBTCS, SC, or SE, number of seizures, and the requirement for intravenous rescue medication was low.

Conclusion

The rapid withdrawal of ASMs to provoke seizures during monitoring for pre-surgical evaluation following the URW protocol was as effective and safe as with RW. Ultra-rapid ASM withdrawal has the benefits of reducing LTM duration and shortening the time to first seizure compared to rapid medication tapering.

The impact of the time to last seizure before admission to the epilepsy monitoring unit (EMU) on epilepsy classifications

INTRODUCTION AND BACKGROUND

The impact of the timing of the last seizure (TTLS) prior to admission to the epilepsy monitoring unit (EMU) on epilepsy classification is unclear for which we conducted this study.

METHODS

We reviewed patients with epilepsy admitted to EMU between January 2021 and April 2022 and identified TTLS before EMU admission. We considered EMU yield as whether; it confirmed epilepsy classification, added new knowledge to the classification, or failed to classify epilepsy.

RESULTS

We studied 156 patients. There were 72 (46%) men, with a mean age of 30. TTLS was divided according to a one- or three-month cutoff. We confirmed the pre-EMU epilepsy classification in 52 (33%) patients, learned new findings on epilepsy classification in 80 (51%) patients, and failed to classify epilepsy in 24 (15%) patients. Patients with "confirmed epilepsy classifications" reported seizures sooner to EMU admission than other groups (0.7 vs. 2.3 months, p-value = 0.02, 95% CI; -1.8, -1.3). Also, the odds of confirming epilepsy classification were more than two times in patients with TTLS within a month compared to those with TTLS of more than a month (OR = 2.4, p-value = 0.04, 95% CI; 1.1, 5.9). The odds were also higher when the 3-month TTLS cutoff was considered (OR = 6.2, p-value = 0.002, 95% CI; 1.6, 40.2). Confirming epilepsy classification was also associated with earlier seizures recorded at one- or three-month cutoff (OR = 2.1 and OR = 2.3, respectively, p-value = 0.05). We did not observe similar findings when we modified the classification or failed to reach a classification.

CONCLUSIONS

The timing of the last seizure before EMU admission appeared to influence the yield of EMU and enhanced the confirmation of epilepsy classifications. Such findings can improve the utilization of EMU in the presurgical evaluation of patients with epilepsy.

Periodic cycles of seizure clustering and suppression in children with epilepsy strongly suggest focal cortical dysplasia

AIM

We investigated characteristic seizure patterns in epilepsy caused by focal cortical dysplasia (FCD), which differ from epilepsy by other aetiologies in surgical cases with lesions on magnetic resonance imaging (MRI), then examined if these features were applicable to patients with epilepsy without any lesions on MRI.

METHOD

We retrospectively studied clinicopathological features in 291 (143 females) children with epilepsy who had undergone resective surgery after comprehensive evaluation, including 277 cases with lesions on MRI (136 females, age at resection 0-17 years [mean 6 years 10 months, SD 5 years 7 months]) and 14 cases without any lesions on MRI (seven females, age 0-16 years [mean 7 years 8 months, SD 4 years 8 months]).

RESULTS

Among 277 patients with lesions on MRI, 87 cases exhibited recurrent periodic cycles of seizure clustering (≥5 seizures/day for ≥1 week) and suppression (no seizures for ≥1 week); of these, 80 cases (92%) were pathologically diagnosed with FCD. Other pathologies included glial scar, hippocampal sclerosis, hemimegalencephaly, and cortical tuber in three, two, one, and one case respectively. All 14 patients without any lesions on MRI had significant recurrent periodic seizure cycles and FCD histopathologically.

INTERPRETATION

Periodic seizure cycles characterized by clustering and suppression in patients with epilepsy strongly suggest the presence of FCD regardless of MRI findings, and comprehensive evaluations for epilepsy surgery should be proceeded.

Prevalence and Predictors of Seizure Clusters in Pediatric Patients With Epilepsy: The Harvard-Yale Pediatric Seizure Cluster Study

BACKGROUND

Determine the prevalence of seizure clusters (two or more seizures in six hours), use of rescue medications, and adverse outcomes associated with seizure clusters in pediatric patients with a range of epilepsy severities, and identify risk factors predictive of seizure clusters.

METHODS

Prospective observational two-center study, including phone call and seizure diary follow-up for 12 months in patients with epilepsy aged one month to 18 years. We classified patients into three risk groups based on seizures within the prior year: high, seizure cluster (two or more seizures within one day); intermediate, at least one seizure but no days with two or more seizures; low, no seizures.

RESULTS

One-third (32.3%; high risk, 72.4%; intermediate risk, 30.4%; low risk, 3.1%) of 297 patients had a seizure cluster during the study, including half (46.2%) of the patients with active seizures at baseline (intermediate- and high-risk groups combined). Emergency room visits or injuries were no more likely due to a seizure cluster than an isolated seizure. Rescue medications were utilized in 15.8% of patients in the high-risk group and 19.2% in the intermediate-risk group. History of status epilepticus (adjusted odds ratio [aOR], 2.13; confidence interval [CI], 1.09 to 4.16]), seizure frequency greater than four per month (aOR, 4.27; CI, 1.92 to 9.50), and high-risk group status (aOR, 6.42; CI, 2.97 to 13.87) were associated with greater odds of seizure cluster.

CONCLUSIONS

Seizure clusters are common in pediatric patients with epilepsy. High seizure frequency was the strongest predictor of clusters. Rescue medications were underutilized. Future studies should evaluate the applicability and effectiveness of these medications for optimization of pediatric seizure cluster treatment and reduction of seizure-related emergency department visits, injuries, and mortality.

Benzodiazepines in the Management of Seizures and Status Epilepticus: A Review of Routes of Delivery, Pharmacokinetics, Efficacy, and Tolerability

Status epilepticus (SE) is an acute, life-threatening medical condition that requires immediate, effective therapy. Therefore, the acute care of prolonged seizures and SE is a constant challenge for healthcare professionals, in both the pre-hospital and the in-hospital settings. Benzodiazepines (BZDs) are the first-line treatment for SE worldwide due to their efficacy, tolerability, and rapid onset of action. Although all BZDs act as allosteric modulators at the inhibitory gamma-aminobutyric acid (GABA)_A receptor, the individual agents have different efficacy profiles and pharmacokinetic and pharmacodynamic properties, some of which differ significantly. The conventional BZDs clonazepam, diazepam, lorazepam and midazolam differ mainly in their durations of action and available routes of administration. In addition to the common intravenous, intramuscular and rectal administrations that have long been established in the acute treatment of SE, other administration routes for BZDs-such as intranasal administration-have been developed in recent years, with some preparations already commercially available. Most recently, the intrapulmonary administration of BZDs via an inhaler has been investigated. This narrative review provides an overview of the current knowledge on the efficacy and tolerability of different BZDs, with a focus on different routes of administration and therapeutic specificities for different patient groups, and offers an outlook on potential future drug developments for the treatment of prolonged seizures and SE.

Comparison of Acute Withdrawal and Slow Taper of Antiseizure Medications during Video Electroencephalographic Monitoring: Efficacy for Shortening of Hospital Stay

Antiepileptic medications (ASMs) are withdrawn at the epilepsy monitoring unit to facilitate seizure recordings. The effect of rapid tapering of ASMs on the length of hospital stay has not been well documented. We compared the mean length of hospital stay between patients who underwent acute ASM withdrawal and slow dose tapering during long-term video electroencephalography (EEG) monitoring. We retrospectively investigated 57 consecutive patients admitted to the epilepsy monitoring unit regarding the mean length of hospital stay in the acute ASM withdrawal group (n = 30) and slow-taper group (n = 27). In the acute-withdrawal group, all ASMs were discontinued once the patients were admitted. In the slow-taper group, the doses of ASMs were gradually reduced by 15–30% daily. We also evaluated the safety of the acute-withdrawal and slow-taper protocols. The mean lengths of hospital stay were 3.8 ± 1.92 and 5.2 ± 0.69 days in the acute-withdrawal and slow-taper groups, respectively (p < 0.005). No severe adverse events, including status epilepticus, were observed. Acute ASM withdrawal has the advantage of significantly reducing the length of hospital stay over slow tapering, without any severe adverse effects.

Minimum standards for inpatient long-term video-EEG monitoring: A clinical practice guideline of the international league against epilepsy and international federation of clinical neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events (see Table S1). For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and establish its clinical utility.

Minimum standards for inpatient long-term video-electroencephalographic monitoring: A clinical practice guideline of the International League Against Epilepsy and International Federation of Clinical Neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events. For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and to establish its clinical utility.

Risk of seizure clusters and status epilepticus following rapid and ultra-rapid medication discontinuation during intracranial EEG monitoring

OBJECTIVE

Anti-seizure medications (ASMs) are discontinued in the course of intracranial EEG (iEEG) monitoring for presurgical evaluation. The ASM withdrawal facilitates an emergence of seizures but may also precipitate seizure clusters (SC) and status epilepticus (SE). The aim of this study was to compare the rates of SC and SE during the ultra-rapid withdrawal (URW) and rapid withdrawal (RW) of ASMs during iEEG.

METHODS

We performed a retrospective observational study of all consecutive patients with drug resistant epilepsy who completed iEEG at our comprehensive epilepsy center from 2012-2018. SC was defined as three or more seizures in 24 h with a return to baseline between the events. SE was defined as ≥ 5 min of clinical seizure or ≥ 10 min of ictal electrographic activity or series of seizures with no return to the neurological baseline between the events.

RESULTS

Of 107 patients who completed iEEG with intracranial grid or strip electrodes, 46 (43%) were male. Median age at the time of iEEG was 35.4 years (interquartile range [IQR], 26.4 - 44.9). Ninety patients (84.1%) had all AEDs held on admission, while 16 patients (15%) underwent a rapid taper. The median time to first seizure was 15.1 (8.2 - 22.6) h. Sixty-two patients (57.9%) developed SC, while 10 (9.4%) developed SE. Twenty-six patients (36.1%) with these complications required intravenous lorazepam or other rescue ASMs, while the remaining patients had spontaneous resolution of seizures; intubations were not required. While there were differences in the proportions in patients who experienced SC, SE, or neither in the URW and RW groups, these differences were not significant at the 0.05 alpha level.

SIGNIFICANCE

Ultra-rapid and rapid ASM withdrawal are accompanied by SC and SE the majority of which terminate spontaneously. These data support the use of either approach of the medication taper for seizure provocation in iEEG.

The safety and efficacy of modifying the admission protocol to the epilepsy monitoring unit in response to the COVID-19 pandemic

PURPOSE

The coronavirus disease 2019 (COVID-19) pandemic has impacted admission to epilepsy monitoring units (EMUs) for classification and presurgical evaluation of patients with refractory epilepsy. We modified the EMU admission protocol via anti-seizure medications (ASM) withdrawal implemented one day before admission; thus, we aimed to evaluate the efficacy and safety of this modified protocol.

METHODS

In January 2021, we initiated ASM tapering 24 h before-rather than on the first day after-EMU admission, contrasting with the previous protocol. We retrospectively reviewed EMU admissions between January and April of 2018, 2019, and 2021, and identified the time required to record the first seizure, and EMU yield to confirm or change the epilepsy classification. We also evaluated the safety of the modified protocol, by monitoring the seizure frequency for up to 5 months after the discharge from the hospital.

RESULTS

One hundred four patients were included (mean age: 30 years, men: 43%); excluding a longer disease duration and abundance of normal routine electro-encephalogram (EEG) in patients admitted before the pandemic, no differences were observed in patients' characteristics. On average, it took 41 h and 21 h to record the first seizure using the standard and modified protocols, respectively (p < 0.001, 95% CI: 10-30). Other characteristics were investigated both before and after the COVID-19 pandemic, and epilepsy classifications were confirmed twice using the modified protocol (OR = 2.4, p = 0.04, 95% CI: 1.1-5.5). Multivariate regression analysis confirmed the shorter time to record the first seizure using the modified admission protocol (23 h less, p < 0.001; 95% CI: 12-34). Finally, 36 (86%) patients admitted during the pandemic exhibited no increase in seizure frequency after the discharge from the hospital.

CONCLUSIONS

Initiating ASM withdrawal one day before EMU admission was deemed to be an efficient and safe way to confirm epilepsy classification and significantly decrease the length of hospital stay. Ultimately, this will shorten the long waiting list for EMU admission created by the COVID-19 pandemic.

Bilateral epileptogenesis in temporal lobe epilepsy due to unilateral hippocampal sclerosis: A case series

INTRODUCTION

Bitemporal epilepsy (biTLE), a potential cause of failure in TLE surgery, is rarely associated with unilateral HS and could be suggested by not lateralizing ictal scalp EEG/interictal PET-FDG findings. We evaluated the proportion of biTLE in a population of drug-resistant TLE-HS subjects who underwent intracranial investigation for lateralizing purpose.

METHODS

We retrospectively included all consecutive refractory TLE-HS patients and not lateralizing ictal scalp EEG/interictal PET-FDG findings, investigated by intracranial bilateral longitudinal hippocampal electrodes. Demographic characteristics, electroclinical findings and seizure outcome were evaluated.

RESULTS

We identified 14 subjects (7 males; mean age 39.5 years; mean age at disease onset 14.4 years), 7 of them had biTLE diagnosed after intracranial investigations. In the remaining 7 with unilateral epileptogenesis (uniTLE) anterior temporal lobectomy was performed (6/7 were in Engel class I). Preoperative neuropsychological assessment differentiated biTLE from uniTLE, as it was normal in six uniTLE patients but only in one with biTLE (p < 0.05).

CONCLUSIONS

Not lateralizing ictal scalp EEG and functional imaging findings in TLEHS should alert about the possibility of a true biTLE also in presence of unilateral findings at MRI. Intracranial investigations with bilateral longitudinal hippocampal electrodes can localize the EZ with a good risk-benefit profile. Consistently with the warning on memory functions in TLE patients explored by using longitudinal hippocampal electrodes, further studies are needed to better define the optimal investigation strategy.

Acute withdrawal of new-generation antiepileptic drugs in epilepsy monitoring units: Safety and efficacy

INTRODUCTION

Acute withdrawal of antiepileptic drugs (AEDs) is a safe and effective approach to provoking seizures in order to complete video-electroencephalogram (V-EEG) studies in a timely manner. Previous studies have focused only on withdrawal from conventional AEDs, and the effects of withdrawal from new-generation AEDs have not been extensively studied.

MATERIALS AND METHODS

This study examined adult patients with drug-resistant epilepsy admitted to an epilepsy monitoring unit between 2015 and 2018. Patients were classified according to whether they received conventional AEDs (Con; n = 13) or new-generation AEDs (N-Gen; n = 26). We then compared the effects of withdrawing these two types of AEDs over a period of one week in terms of efficacy (time to complete V-EEG monitoring) and safety, including the incidence of cluster seizures (CS), focal to bilateral tonic-clonic seizures (FBTCS) and status epilepticus (SE).

RESULTS

In both groups, approximately one week was required to complete V-EEG analysis: N-Gen group (5.6 days) and Con group (6.3 days). No differences were observed between the two groups in terms of the median number of seizures, the onset of the 1st seizure, the distribution of CS, FBTCS, or SE. Following acute withdrawal of medication, a high percentage of patients with a history of CS or FBTCS, respectively, presented CS or FBTCS.

CONCLUSIONS

We did not observe significant differences between patients taking new-generation AEDs and those taking conventional AEDs following withdrawal during V-EEG recording. In the current study, we employed a standard protocol for the rapid withdrawal of AEDs (daily dose reduction of 50%), which was sufficient for 80% of patients to complete V-EEG monitoring within one week.

Seizure Clusters: Morbidity and Mortality

Seizure clusters, an intermediate between single seizure and status epilepticus, are associated with morbidity, impaired quality of life, and premature mortality. The relationship between seizure clusters and sudden unexplained death in epilepsy (SUDEP) is poorly understood. Here, we define seizure clusters; review comorbid psychiatric disorders and memory deficits associated with seizure clusters; and review cases of witnessed SUDEP for which seizure frequency prior to death is available. Patients with a history of seizure clusters have a 2.5 fold increased risk for SUDEP, and one third of patients with monitored in hospital SUDEP experienced a cluster of generalized tonic clonic seizures prior to death. Understanding the effects of seizure frequency and duration on SUDEP risk could yield new insights in SUDEP pathophysiology and new targets for intervention.

Seizure Clusters, Seizure Severity Markers, and SUDEP Risk

Rationale: Seizure clusters may be related to Sudden Unexpected Death in Epilepsy (SUDEP). Two or more generalized convulsive seizures (GCS) were captured during video electroencephalography in 7/11 (64%) patients with monitored SUDEP in the MORTEMUS study. It follows that seizure clusters may be associated with epilepsy severity and possibly with SUDEP risk. We aimed to determine if electroclinical seizure features worsen from seizure to seizure within a cluster and possible associations between GCS clusters, markers of seizure severity, and SUDEP risk. Methods: Patients were consecutive, prospectively consented participants with drug-resistant epilepsy from a multi-center study. Seizure clusters were defined as two or more GCS in a 24-h period during the recording of prolonged video-electroencephalography in the Epilepsy monitoring unit (EMU). We measured heart rate variability (HRV), pulse oximetry, plethysmography, postictal generalized electroencephalographic suppression (PGES), and electroencephalography (EEG) recovery duration. A linear mixed effects model was used to study the difference between the first and subsequent seizures, with a level of significance set at p < 0.05. Results: We identified 112 GCS clusters in 105 patients with 285 seizures. GCS lasted on average 48.7 ± 19 s (mean 49, range 2-137). PGES emerged in 184 (64.6%) seizures and postconvulsive central apnea (PCCA) was present in 38 (13.3%) seizures. Changes in seizure features from seizure to seizure such as seizure and convulsive phase durations appeared random. In grouped analysis, some seizure features underwent significant deterioration, whereas others improved. Clonic phase and postconvulsive central apnea (PCCA) were significantly shorter in the fourth seizure compared to the first. By contrast, duration of decerebrate posturing and ictal central apnea were longer. Four SUDEP cases in the cluster cohort were reported on follow-up. Conclusion: Seizure clusters show variable changes from seizure to seizure. Although clusters may reflect epilepsy severity, they alone may be unrelated to SUDEP risk. We suggest a stochastic nature to SUDEP occurrence, where seizure clusters may be more likely to contribute to SUDEP if an underlying progressive tendency toward SUDEP has matured toward a critical SUDEP threshold.

Effects of Vagus Nerve Stimulation on Sustained Seizure Clusters: A Case Report

Seizure clusters (SCs) are acute repetitive seizures with acute episodes of deterioration during seizure control. SCs can be defined as a series of grouped seizures with short interictal periods. Vagus nerve stimulation (VNS) is a treatment option for drug-resistant epilepsy. We present a case where VNS suppressed epileptic SCs, which had persisted for several months. A 13-year-old boy with congenital cerebral palsy and mental retardation had drug-resistant epilepsy with daily jerking movements and spasms in both sides of his body. The seizures were often clustered, and he experienced two sustained SC episodes that persisted for a few months even with prolonged use of continuous intravenous midazolam (IV-MDZ). The patient underwent VNS device placement at the second sustained SC and rapid induction of VNS. Because the tapering of IV-MDZ did not exacerbate the SC, midazolam was discontinued 4 weeks after VNS initiation. Non-refractory SCs also disappeared 10 months after VNS. The seizure severity was improved, and the frequency of seizures reduced from daily to once every few months. The epileptic activity on electroencephalography (EEG) significantly decreased. This case highlights VNS as an additional treatment option for SC. VNS may be a therapeutic option if SC resists the drugs and sustains. Additional studies are necessary to confirm our findings and to investigate how device implantation and stimulation parameters affect the efficacy of VNS.

Visuo-verbal distinction revisited: new insights from a study on temporal lobe epilepsy patients in the debate over the lateralization of material-specific and process-specific aspects of memory

Introduction: The automatic interaction between a cue and a memory trace can give rise to the vivid recollection of a purely sensory past experience. But are humans able to reach back intentionally to purely sensory experiences in the absence of any exogenous or endogenous cue? In the present study, we propose an alternative hypothesis, claiming that the retrieval of associated semantic memories, stored in the left hemisphere and acting as endogenous cues, is a prerequisite for intentionally recollecting sensory experience stored in the right hemisphere during mental time travels (MTT). Methods: To investigate this issue, we administered an MTT task to 26 epileptic patients (16 males and 10 females) who had undergone right or left temporal lobectomy and to 28 age and education matched controls. The task was devised so as to require the recollection of purely visual memories in the absence of external cues. Participants also performed two conventional recognition tasks with visual and verbal materials. The three between-subjects memory tasks were analyzed separately with the Kruskal-Wallis test and the Wilcoxon rank-sum test in order to investigate differences across groups. According to our hypothesis, we expected side asymmetries in the patients' performance on the two recognition tasks but not the MTT task. Results: While patients showed the well-known hemispheric asymmetry for visual and verbal material in the (external-cue dependent) recognition tasks, no side asymmetries emerged in the purely visual MTT task. Conclusions: In keeping with the view that visual memories cannot be targeted directly by a strategic search process, the lack of any side asymmetry in our MTT task can be interpreted as a trade-off between left-sided strategic search for associated semantic memories and right-sided storage of visual ones.

Association of cortical spreading depression and seizures in patients with medically intractable epilepsy

OBJECTIVE

Monitoring of the ultra-low frequency potentials, particularly cortical spreading depression (CSD), is excluded in epilepsy monitoring due to technical barriers imposed by the scalp ultra-low frequency electroencephalogram (EEG). As a result, clinical studies of CSD have been limited to invasive EEG. Therefore, the occurrence of CSD and its interaction with epileptiform field potentials (EFP) require investigation in epilepsy monitoring.

METHODS

Using a novel AC/DC-EEG approach, the occurrence of DC potentials in patients with intractable epilepsy presenting different symptoms of aura was investigated during long-term video-EEG monitoring.

RESULTS

Various forms of slow potentials, including simultaneous negative direct current (DC) potentials and prolonged EFP, propagated negative DC potentials, and non-propagated single negative DC potentials were recorded from the scalp of the epileptic patients. The propagated and single negative DC potentials preceded the prolonged EFP with a time lag and seizure appeared at the final shoulder of some instances of the propagated negative DC potentials. The slow potential deflections had a high amplitude and prolonged duration and propagated slowly through the brain. The high-frequency EEG was suppressed in the vicinity of the negative DC potential propagations.

CONCLUSIONS

The study is the first to report the recording of the propagated and single negative DC potentials with EFP at the scalp of patients with intractable epilepsy. The negative DC potentials preceded the prolonged EFP and may trigger seizures. The propagated and single negative DC potentials may be considered as CSD.

SIGNIFICANCE

Recordings of CSD may serve as diagnostic and prognostic monitoring tools in epilepsy.

Antiepileptic drug withdrawal and seizure severity in the epilepsy monitoring unit

OBJECTIVE

The goal of this study was to identify a strategy for antiepileptic drug (AED) reduction to allow efficient recording of focal seizures (FS) in patients undergoing video-electroencephalography (EEG) in an epilepsy monitoring unit (EMU) while avoiding the risk of complications associated with more severe seizure types.

METHODS

We retrospectively reviewed consecutive patients admitted to our institution's EMU from July 1, 2016 to December 31, 2017. We included 114 presurgical patients who had AEDs reduced and at least one seizure during the admission. We compared AED dosages at which FS versus focal to bilateral tonic-clonic seizures (f-BTCS), seizure clusters, and lorazepam administration occurred. We also examined rate of AED reduction and seizure types. We used a receiver-operating characteristic (ROC) curve to identify a dose maximizing FS and minimizing other seizure types.

RESULTS

Antiepileptic drug withdrawal rates ranged from 0 to 100% in the first 24 h (mean: 20%, standard deviation: 20%). Focal to bilateral tonic-clonic seizures and lorazepam administration occurred at a lower median AED dose than did FS (0%, 7.2%, and 43.8%, respectively, expressed as a percentage of the patient's outpatient daily AED dose; p < 0.001). A daily EMU-administered dose of one-third of the patient's outpatient AED dose allowed 55.0% of FS to occur while avoiding 82.0% of more severe seizure types. The seizure types had no difference in rate of AED withdrawal in the first 24 h of EMU stay.

CONCLUSIONS

Focal seizures occurred at a higher AED dose than did f-BTCS. This may imply that a low minimally effective dose of AED could allow FS to be recorded while providing protection against f-BTCS. This strategy could improve efficacy and safety in the EMU.

Drug withdrawal in the epilepsy monitoring unit - The patsalos table

Investigation of possible candidates for epilepsy surgery will usually require inpatient EEG to capture seizures and allow full operative planning. Withdrawal of antiepileptic drugs increases the yield of this valuable diagnostic information and the benefits of this should justify any increase in the risk of harm associated with these seizures This paper outlines our opinion on what would constitute proposed best practice for management of antiepileptic drug (AED) dosing when patients are admitted for monitoring of seizures to an epilepsy monitoring unit (EMU). In the vast majority of cases EMU admissions are safe and, even if seizures occur, will pass off without complication. Previous guidance has concentrated on ensuring practice around technical aspects of EEG monitoring itself and staffing within the unit. In this guidance we aim to outline optimally safe ways of ensuring that EMUs ensure the minimisation of risk to the patients admitted under their care. We propose an algorithm for enhancing the safety of AED withdrawal in VT admissions while ensuring adequate seizure yields. Risk minimisation requires planned management of drug dosing (with reduction if appropriate), provision of adequate rescue medication, and adequate supervision to allow rapid response to generalised seizures. This algorithm is accompanied by a table which uses knowledge of the clinical and pharmacological properties of each AED to ensure dose withdrawal and reduction is timely and safe taking into account the severity and frequency of the individual's seizures.

Prevalence and predictors of seizure clusters: A prospective observational study of adult patients with epilepsy

OBJECTIVE

The purpose of this prospective observational study was to describe the prevalence and adverse outcomes associated with seizure clusters (defined as ≥2 seizures in a 6-hour period) in a large sample of adult patients with a range of epilepsy severities and to identify clinical characteristics predictive of clustering.

METHODS

Patients maintained a seizure diary and were contacted monthly to verify compliance and data accuracy. Logistic regression models were utilized to test associations between individual patient demographic/clinical characteristics and seizure clustering. Fisher's exact test was utilized to test associations between rescue medication use and adverse seizure-related outcomes.

RESULTS

A total of 300 patients were followed prospectively for one year; 247 patients qualified for final analysis. Six-hour seizure clusters occurred in 45.8% of patients with active epilepsy at enrollment, including 62.7% of those with prior day-clusters and 30.0% of those without prior day-clusters. The odds of clustering were markedly greater among patients who reported a higher seizure frequency (>4 seizures per year vs. 1-4 seizures per year) (adjusted odds ratio (OR): 8.9; 95% confidence interval (CI): 3.2-24.6; p < 0.0001) and among patients with prior day-clusters (adjusted OR: 11.0; 95% CI: 1.2-104.2; p = 0.036). Rescue medication use was associated with significantly fewer injuries and emergency department visits, but rescue medication was underutilized.

CONCLUSIONS

Seizure clusters are common, occurring in nearly half of adult patients with active epilepsy followed prospectively over one year, and are more frequent in those with higher seizure frequencies and prior day-clusters. Although underutilized, rescue medication was associated with fewer injuries and emergency department visit.

Characteristics of large patient-reported outcomes: Where can one million seizures get us?

Objective

To analyze data from Seizure Tracker, a large electronic seizure diary, including comparison of seizure characteristics among different etiologies, temporal patterns in seizure fluctuations, and specific triggers.

Methods

Zero‐inflated negative binomial mixed‐effects models were used to evaluate temporal patterns of seizure events (during the day or week), as well as group differences in monthly seizure frequency between children and adults and between etiologies. The association of long seizures with seizure triggers was evaluated using a mixed‐effects logistic model with subject as the random effect. Incidence rate ratios (IRRs) and odds ratios were reported for analyses involving zero‐inflated negative binomial and logistic mixed‐effects models, respectively.

Results

A total of 1,037,909 seizures were logged by 10,186 subjects (56.7% children) from December 2007 to January 2016. Children had more frequent seizures than adults did (median monthly seizure frequency 3.5 vs. 2.7, IRR 1.26; p < 0.001). Seizures demonstrated a circadian pattern (higher frequency between 07:00 a.m. and 10:00 a.m. and lower overnight), and seizures were reported differentially across the week (seizure rates higher Monday through Friday than Saturday or Sunday). Longer seizures (>5 or >30 min) had a higher proportion of the following triggers when compared with shorter seizures: “Overtired or irregular sleep,” “Bright or flashing lights,” and “Emotional stress” (p < 0.004).

Significance

This study explored a large cohort of patients with self‐reported seizures; strengths and limitations of large seizure diary databases are discussed. The findings in this study are consistent with those of prior work in smaller validated cohorts, suggesting that patient‐recorded databases are a valuable resource for epilepsy research, capable of both replication of results and generation of novel hypotheses.

Outcome prediction in patients with acute repetitive seizures: Application of the Status Epilepticus Severity Score

Acute repetitive seizures (ARS) pose a risk of hospital admission with status epilepticus and a mortality threat, which underscores the need for the early prediction of a clinical course. Unfortunately, little attention has been given to ARS in this context, even though we possess the appropriate predictive tools for the stages of status epilepticus. Therefore, the main aim of this study was to assess the prognostic value of the Status Epilepticus Severity Score (STESS) in the population of patients with ARS. The study included a population of 200 patients. Almost half of the patients had achieved seizure cessations after diazepam administration, whereas 19.5% progressed to status epilepticus despite antiepileptic drug treatment. Mortality reached 10.5% of the total population. The receiver operating characteristic (ROC) curve for prediction of death by the STESS had an area under the curve (AUC) of 0.901, with an optimal cutoff point for discrimination ≥2 (sensitivity 0.95, specificity 0.71, and Youden index 0.66). Hosmer-Lemeshow indicated good calibration of the STESS (chi-square goodness-of-fit test = 3.24; P = .919). The study shows excellent effectiveness of the STESS in the prognosis of the clinical course in patients with ARS. STESS may be a valuable tool for the proper planning of diagnostic and therapeutic activities in this population.

Seizure clustering during presurgical electroencephalographic monitoring in children

BACKGROUND

Presurgical evaluation with antiseizure medication tapering in patients with refractory epilepsy places them at risk for seizure clustering or prolonged seizures. We looked at the occurrence of seizure clustering (3 or more seizures within 24h) and prolonged seizures and the factors that influence seizure clustering and affect length of stay (LOS) in pediatric patients during presurgical monitoring.

METHODS

We retrospectively reviewed the medical records of all consecutive admissions to the epilepsy monitoring unit (EMU) and included patients undergoing noninvasive presurgical evaluation. Data were extracted regarding demographics, seizure history, details of the EMU admission including occurrence of seizure clusters, prolonged seizures, status epilepticus, treatment, and LOS.

RESULTS

Sixty-nine patients met our inclusion criteria. Seizure clustering during monitoring was observed in 33 patients (48%). Prolonged seizures lasting >5min was observed in 14 (20%) patients including 2 with status epilepticus (3%). Seizure clusters necessitated rescue treatment in around 30%. History of seizure clustering at home was the only factor associated with the occurrence of seizure clustering during the EMU stay (p<0.0001). The LOS did not differ significantly between patients who had seizure clustering during monitoring versus those who did not (p=0.369).

CONCLUSIONS

Seizure clustering was common in children undergoing presurgical monitoring and seen especially in those with a history of seizure clustering at home. Occurrence of seizure clustering did not prolong the LOS but necessitated the use of rescue medications in about a third of the patients with seizure clusters due to multiple seizures.

Safety and efficiency of medication withdrawal at home prior to long-term EEG video-monitoring

PURPOSE

Long-term video-EEG monitoring (LTM) is frequently used for diagnostic purposes and in the workup of epilepsy surgery to determine the seizure onset zone. Different strategies are applied to provoke seizures during LTM, of which withdrawal of anti-epileptic drugs (AED) is most effective. Remarkably, there is no standardized manner of AED withdrawal. For instance, the majority of clinics taper medication during clinical admission, whereas we prefer to taper medication at home prior to admission. Our aim was to study the advantages (efficiency and diagnostic yield) and disadvantages (safety and complication rates) of predominantly tapering of medication at home.

METHOD

We report a retrospective observational cohort of 273 patients who had a LTM at our tertiary epilepsy center from 2005 until 2011. Provocation methods to induce seizures were determined on individual basis. Success rate (duration of admittance, time to first seizure, efficiency and diagnostic yield) and complications and serious adverse events were assessed.

RESULTS

AED were tapered in 180 (66%) patients, in 93 (24%) of these patients with additional (partial) sleep deprivation. In all of these patients tapering started at home one to four weeks prior to admission. In the other patients, only (partial) sleep deprivation or none provocation method at all was applied. Seizure recordings were successful in 79,9% of patients. Complications occurred in 19 patients (10.9%) of which 3 had (1.7%) serious adverse events (status epilepticus (SE)) with AED withdrawal. These complications only occurred during admittance, not at home.

CONCLUSIONS

AED withdrawal at home prior to LTM is an efficient and convenient method to increase the diagnostic yield of LTM and appears relatively safe.

Identifying seizure clusters in patients with psychogenic nonepileptic seizures

The present study explored how seizure clusters may be defined for those with psychogenic nonepileptic seizures (PNES), a topic for which there is a paucity of literature. The sample was drawn from a multisite randomized clinical trial for PNES; seizure data are from participants' seizure diaries. Three possible cluster definitions were examined: 1) common clinical definition, where ≥3 seizures in a day is considered a cluster, along with two novel statistical definitions, where ≥3 seizures in a day are considered a cluster if the observed number of seizures statistically exceeds what would be expected relative to a patient's: 1) average seizure rate prior to the trial, 2) observed seizure rate for the previous seven days. Prevalence of clusters was 62-68% depending on cluster definition used, and occurrence rate of clusters was 6-19% depending on cluster definition. Based on these data, clusters seem to be common in patients with PNES, and more research is needed to identify if clusters are related to triggers and outcomes.

Effective withdrawal of antiepileptic drugs in premonitoring admission to capture seizures during limited video-EEG monitoring

Objective

Withdrawal of antiepileptic drugs (AEDs) is commonly applied to capture seizures in video‐EEG (vEEG) monitoring for patients with infrequent but intractable seizures. Because of the half‐life of AEDs, AED withdrawal during only vEEG tends to be inadequate to provoke seizures within the vEEG admission. We hypothesize that prewithdrawal of long‐half‐life AEDs in premonitoring admission (PMA) is safe and effective to capture seizures in the limited time of vEEG. We determined the effect of half‐life on the interval between AED withdrawal and seizure occurrence.

Methods

We collected 87 patients with three criteria: (1) seizure occurrence ≤3 per month; (2) AEDs ≥2; (3) AED withdrawal during their admission, among 126 consecutive patients who underwent vEEG in the Department of Neurosurgery, Hiroshima University Hospital between 2011 and 2014. We divided patients into two groups on the basis of half‐life of AED: Group A (23 patients) with phenobarbital (PB) and/or zonisamide (ZNS); Group B (64 patients) with other AEDs. In Group A, PB and ZNS were withdrawn during 4‐day PMA before vEEG started. Further AED withdrawal was performed during vEEG, depending on the seizure occurrence.

Results

The number of AEDs on admission was significantly higher in Group A (2–6, 3.5 ± 0.9; range, mean ±SD) than in Group B (2–5, 2.8 ± 0.8) (p < 0.01). All 23 Group A patients and 13 (20%) Group B patients underwent AED withdrawal during PMA. Seizures occurred during PMA in two patients in both Group A (9%) and Group B (15%). The first seizure occurred significantly longer after the start of withdrawal in Group A (6.1 ± 2.0 days) than in Group B (2.8 ± 1.3 days) (p < 0.01). Seizures were equally captured between both groups: 96% in Group A and 92% in Group B during vEEG.

Significance

For epilepsy patients who are treated with PB and/or ZNS, we recommend the planning of AED withdrawal during PMA before the start of vEEG to succeed in capturing seizures during the limited time of vEEG monitoring.

Drug taper during long-term video-EEG monitoring: efficiency and safety

OBJECTIVES

Anti-epileptic drugs (AED) are often tapered to reduce the time needed to record a sufficient number of seizure during long-term video-EEG monitoring (LTM). Fast AED reduction is considered less safe, but few studies have examined this. Our goal is to examine whether the rate of AED reduction affects efficiency and safety.

MATERIALS & METHODS

We performed a retrospective observational study of patients referred for presurgical evaluation. Each patient was categorized by two dichotomous parameters of AED tapering: (i) fast vs slow AED reduction the first 24 h of LTM and (ii) complete vs partial AED discontinuation during LTM.

RESULTS

Of 79 patients, 51% underwent a fast AED reduction and 58% ended up with AEDs completely discontinued. Complete AED discontinuation was associated with three times increased likelihood of receiving rescue therapy during LTM and double risk of having secondary generalized tonic-clonic seizures (sGTCS) compared to the group partially discontinued. Fast vs slow AED reduction had no effect on the safety of LTM. The fast AED reduction group and the complete AED discontinuation group had a significantly longer time to first seizure and total recording time compared to the slow AED reduction and partial discontinuation groups, respectively.

CONCLUSIONS

Fast AED reduction was found safe in patients undergoing presurgical video-EEG monitoring. Patients completely discontinued from AEDs had more sGTCS than patients partially discontinued. Further studies are suggested to confirm this finding and to evaluate whether fast reduction is safe and efficient in other subgroups of patients referred for LTM.

Efficacy of naloxone in reducing postictal central respiratory dysfunction in patients with epilepsy: study protocol for a double-blind, randomized, placebo-controlled trial

Background

Generalized tonic-clonic seizures (GTCSs) are the main risk factor for sudden unexpected death in epilepsy (SUDEP). Experimental and clinical data strongly suggest that the majority of SUDEP results from a postictal respiratory dysfunction progressing to terminal apnea. Postictal apnea could partly derive from a seizure-induced massive release of endogenous opioids. The main objective of this study is to evaluate the efficacy of an opioid antagonist, naloxone, administered in the immediate aftermath of a GTCS, in reducing the severity of the postictal central respiratory dysfunction.

Methods/design

The Efficacy of Naloxone in Reducing Postictal Central Respiratory Dysfunction in Patients with Epilepsy (ENALEPSY) study is a multicenter, double-blind, randomized, placebo-controlled trial conducted in patients with drug-resistant focal epilepsy who are undergoing long-term video-electroencephalogram (EEG) monitoring (LTM) in an epilepsy monitoring unit (EMU). We plan to randomize 166 patients (1:1) to receive intravenous naloxone (0.4 mg) or placebo in the immediate aftermath of a GTCS. Because inclusion in the study needs to take place prior to the occurrence of the GTCS, and because such occurrence is observed in about one-fourth of patients undergoing LTM, we plan to include a maximum of 700 patients upon admission in the EMU. The primary endpoint will be the proportion of patients whose oxygen saturation is <90 % between 1 and 3 min after the end of a GTCS. Secondary outcomes will include the following: the proportion of patients who show postictal apnea, the occurrence and duration of postictal generalized EEG suppression, the total duration of the postictal coma, postictal pain, and the number of patients who have a second GTCS within 120 min after the intravenous injection.

Discussion

The demonstration of naloxone’s efficacy on the severity of postictal hypoxemia will have two primary consequences. First, naloxone would be the first and only therapeutic approach that could be delivered immediately to reverse postictal apnea. Second, demonstration that an opioid antagonist can effectively reduce postictal apnea would pave the way for an assessment of a preventive therapy for SUDEP targeting the same pathophysiological pathway using oral administration of naltrexone.

Trial registration

ClinicalTrials.gov identifier: NCT02332447. Registered on 5 January 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1653-1) contains supplementary material, which is available to authorized users.

Reasons for prolonged length of stay in the epilepsy monitoring unit

Epilepsy monitoring unit (EMU) admissions are essential for the classification/localization of epileptic seizures (ES) and psychogenic non-epileptic seizures (PNES). However, the duration of admissions is highly variable. Accordingly, we evaluated the duration of 596 EMU admissions and reasons for prolonged (>7 days) lengths of stay (LOS). The average LOS was longer for patients diagnosed with ES (8.0 days, SD 4.1 days) than all others (6.0 days, SD 3.9 days, p<0.001). Of the 596 admissions, 231 (38.8%) had prolonged LOS. The most commonly reported reason for prolonged stay was need to record additional seizures (33%). Other contributors included complications such as seizure clusters (6.9%), status epilepticus (1.6%), test complications (3.7%), psychiatric concerns (4.3%), and medication side effects (1.6%). Our results suggest multiple factors produce prolonged LOS with no factor accounting for the majority. Recording an insufficient number of all habitual seizures was the leading cause, which was over twice the percentage of reported complications (17.6%). However, being able to prolong admissions when necessary resulted in only 14.9% of admissions being inconclusive, potentially justifying the extra expense. Efforts to shorten LOS may be best directed at faster recording of seizures, but this may increase LOS due to complications. Our results may be helpful when assessing whether efforts to shorten LOS are useful in improving the quality and cost of care.

Safety in the epilepsy monitoring unit: A retrospective study of 524 consecutive admissions

The yield of monitoring patients at an epilepsy monitoring unit (EMU) depends on the recording of paroxysmal events in a timely fashion, however, increasing the risk of safety adverse events (AEs). We aimed to retrospectively study the frequency and risk factors for AE occurrences in all consecutive admissions to an adult EMU in a tertiary medical center. We also compared our findings with published data from other centers. Between January 2011 and June 2014, there were 524 consecutive admissions to the adult EMU at the Tel Aviv Sourasky Medical Center. Adverse events were recorded in 47 (9.0%) admissions. The most common AE was 4-hour seizure cluster (58.7% of AEs) and, in decreasing frequency, AEs related to antiepileptic drugs (AEDs, 11.1%), falls and traumatic injuries (9.5%), intravenous line complications (9.5%), electrode-related (4.8%), status epilepticus (SE, 3.2%), and cardiac (1.6%) and psychiatric (1.6%) complications. There were significantly more AEs among patients with a younger age at disease onset (p=0.005), a history of temporal lobe epilepsy (p=0.046), a history of focal seizures with altered consciousness (p=0.008), a history of SE (p=0.022), use of a vagal nerve stimulator (p=0.039), and intellectual disability (p=0.016) and when the indication for EMU monitoring was noninvasive or invasive presurgical evaluation (p=0.001). Adverse events occurred more frequently when patients had more events in the EMU (p=0.001) and among those administered carbamazepine (p=0.037), levetiracetam (p=0.004), clobazam (p=0.008), and sulthiame (p=0.016). Patients with a history of psychogenic nonepileptic seizures (PNESs) had significantly fewer AEs (p=0.013). Adverse events were not associated with the age, gender, duration of hospitalization or monitoring, AED withdrawal and renewal, seizure frequency by history, presence of major psychiatric comorbidities, abnormal neurological exam, or the presence of a lesion as on brain magnetic resonance imaging. In conclusion, this study reveals that AEs are not unusual in the EMU and that seizure clustering is the most common among them. Adverse events occur more frequently in patients with more severe epilepsy and intellectual disability and in patients undergoing presurgical evaluations and less frequently in patients with PNESs.

Temporal pole abnormalities in temporal lobe epilepsy with hippocampal sclerosis: Clinical significance and seizure outcome after surgery

PURPOSE

To assess the clinical significance of temporal pole abnormalities (temporopolar blurring, TB, and temporopolar atrophy, TA) in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS) with a long post-surgical follow-up.

METHODS

We studied 60 consecutive patients with TLE-HS and 1.5 preoperative MRI scans who underwent surgery and were followed up for at least 5 years (mean follow-up 7.3 years). Based on findings of pre-surgical MRI, patients were classified according to the presence of TB or TA. Groups were compared on demographic, clinical, neuropsychological data, and seizure outcome.

RESULTS

TB was found in 37 (62%) patients, while TA was found in 35 (58%) patients, always ipsilateral to HS, with a high degree of overlap (83%) between TB and TA (p<0.001). Patients with TB did not differ from those without TB with regard to history of febrile convulsions, GTCSs, age of epilepsy onset, side of surgery, seizure frequency, seizure outcome, and neuropsychological outcome. On the other hand, they were significantly older, had a longer duration of epilepsy, and displayed lower preoperative scores on several neuropsychological tests. Similar findings were observed for TA. Multivariate analysis corroborated the association between temporopolar abnormalities and age at onset, age at surgery (for TB only), and lower preoperative scores on some neuropsychological tests.

CONCLUSIONS

Temporopolar abnormalities are frequent in patients with TLE-HS. Our data support the hypothesis that TB and TA are caused by seizure-related damages. These abnormalities did not influence seizure outcome, even after a long-term post-surgical follow-up.

Use of an online epilepsy diary to characterize repetitive seizures

SIGNIFICANCE

Little is known about patterns of seizures that occur multiple times a day, sometimes called clusters or serial seizures.

OBJECTIVE

The online diary, My Epilepsy Diary (MED), provided self-reported data from community-based patients to describe the characteristics of clusters.

METHODS

We used MED data to define a population of 5098 community outpatients, including 1177 who specified time of multiple seizures in a 24-hour period. Outcomes included cluster prevalence and frequency, distribution of interseizure time intervals, as well as the types of triggers commonly reported.

RESULTS

One-fourth of days with any seizures included clusters for these patients. Most days with clusters included 2 seizures, with >5 events occurring in only 10% of days. One-third of seizures occurred within 3h of the initial event and two-thirds within 6h. When more than 2 seizures occurred, the time to the next seizure decreased from an average of over 2h (to the 3rd event) to a quarter-hour (from the 4th to the 5th event).

CONCLUSION

My Epilepsy Diary data have provided the first overview of cluster seizures in a large community-based population. Treatments with less than 3-hour duration of action would be bioavailable at the time of only one-third of subsequent seizures. Although limited by the self-reported and observational nature of the diary data, some general patterns emerge and can help to focus questions for future studies.

[French guidelines on electroencephalogram]

Electroencephalography allows the functional analysis of electrical brain cortical activity and is the gold standard for analyzing electrophysiological processes involved in epilepsy but also in several other dysfunctions of the central nervous system. Morphological imaging yields complementary data, yet it cannot replace the essential functional analysis tool that is EEG. Furthermore, EEG has the great advantage of being non-invasive, easy to perform and allows control tests when follow-up is necessary, even at the patient's bedside. Faced with the advances in knowledge, techniques and indications, the Société de Neurophysiologie Clinique de Langue Française (SNCLF) and the Ligue Française Contre l'Épilepsie (LFCE) found it necessary to provide an update on EEG recommendations. This article will review the methodology applied to this work, refine the various topics detailed in the following chapters. It will go over the summary of recommendations for each of these chapters and underline proposals for writing an EEG report. Some questions could not be answered by the review of the literature; in those cases, an expert advice was given by the working and reading groups in addition to the guidelines.

Patients' safety in the epilepsy monitoring unit: time for revising practices

PURPOSE OF REVIEW

Long-term video-electroencephalography monitoring (LTM) in epilepsy monitoring units (EMUs) exposes patients to a variety of serious adverse events (SAEs) and safety issues, which have recently caught attention and are summarized in this review.

RECENT FINDINGS

SAEs observed during LTM affect about 10% of patients and include secondary generalized tonic-clonic seizures, seizure clusters and status epilepticus, unusual for the patient; seizure-related falls, injuries, fractures, and aspiration; postictal psychosis; and cardiorespiratory distress, including sudden unexpected death in epilepsy (SUDEP) and near-SUDEP, which were encountered by more than 10% of European and Australian EMUs. Accordingly, 3% of US-based EMUs suffer a death within a 1-year duration census. Many of these SAEs might be promoted by antiepileptic drugs (AEDs) withdrawal, for which no specific guideline is currently available. Current recommendations regarding optimal organization of EMUs, and in particular continuous supervision by a dedicated staff, are not followed by respectively 20 and 26% of European and US-based EMUs.

SUMMARY

SAEs during LTM are a significant concern and might be aggravated by suboptimal EMU organization and staff education. Lack of high-level evidence stands out as the main limiting factor to the development and dissemination of appropriate guidelines.

Withdrawal of antiepileptic drugs during presurgical video-EEG monitoring: an observational study for evaluation of current practice at a referral center for epilepsy

OBJECTIVES

Withdrawal of antiepileptic drugs (AEDs) before and during video-EEG-monitoring is commonly implemented to reduce time needed to register a sufficient number of seizures during presurgical evaluation. There are, however, few guidelines regarding withdrawal rate and observation time.

MATERIAL AND METHODS

We performed an observational study including sixty patients admitted to the national Norwegian epilepsy centre and registered tapering of AEDs and their effect on seizure rate and possible complications.

RESULTS

The mean daily seizure rate before admission to the EMU was 0.4 (range 0.02-4) increasing to 1.1 (range 0-8) at the EMU. 29 patients (48%) followed a slow tapering rate whereas 31 (52%) had an intermediate tapering rate. There was no significant difference between the patients with a daily seizure rate during LTM of more or <0.7 seizures per day, an increase of seizure frequency from habitual to during LTM of more or <3.3 or 6.9 with regard to rate of tapering (slow vs intermediate) etiology or AED monotherapy vs polytherapy. Twenty-six patients (43%) had a sufficient number of seizures registered within 3 days to conclude regarding the presurgical evaluation. Two patients received escape treatment while 25 patients did have 24 h-seizure-clusters. There was no serious event.

CONCLUSIONS

Less than 50% of the patients got a sufficient number of seizures for a conclusive result within 3 days. An increase in the registration period could increase the number of successful registrations.

Is rapid withdrawal of anti-epileptic drug therapy during video EEG monitoring safe and efficacious?

PURPOSE

Video electroencephalographic monitoring (VEM) is used to record ictal and interictal epileptiform activity and to ascertain the level of concordance between the two. Often, taper or discontinuation of anti-epileptic (AED) therapy is needed to facilitate seizure occurrence. The safety of this practice is unclear and long-term sequelae have yet to be elucidated.

METHODS

This is a prospective study of 158 patients subjected to combined sleep-deprived VEM with rapid AED withdrawal, for evaluation of seizure-like episodes over 24 months under the care of an epileptologist with direct nursing observation and EEG technician support in our telemetry unit. In most cases, AEDs were discontinued within 24h of admission. We assessed the diagnostic yield and safety of VEM as well as epilepsy surgery outcomes.

RESULTS

VEM answered the study question in 90.5% of cases but failed to record ictal events in 9.5%. This diagnostic yield was achieved over a mean VEM duration of 4.53±1.44 days, with no benefit of longer monitoring. These findings improved quality of life by optimizing medical and surgical therapeutic planning, leading to improved seizure control. Overall, 32.9% of the cohort received epilepsy surgery. The complication rate was 5.06%, characterized largely by musculoskeletal pain secondary to clinical seizure activity, with no mortality observed. In the first month following VEM 2.5% of patients received emergency-room admission for seizure clustering.

CONCLUSIONS

VEM with combined sleep deprivation and protocolized rapid AED withdrawal is a safe and effective investigative technique with no adverse long-term sequelae. It is a reliable strategy for therapeutic planning and can be used to determine candidacy for surgical treatment.

Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study

BACKGROUND

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in people with chronic refractory epilepsy. Very rarely, SUDEP occurs in epilepsy monitoring units, providing highly informative data for its still elusive pathophysiology. The MORTEMUS study expanded these data through comprehensive evaluation of cardiorespiratory arrests encountered in epilepsy monitoring units worldwide.

METHODS

Between Jan 1, 2008, and Dec 29, 2009, we did a systematic retrospective survey of epilepsy monitoring units located in Europe, Israel, Australia, and New Zealand, to retrieve data for all cardiorespiratory arrests recorded in these units and estimate their incidence. Epilepsy monitoring units from other regions were invited to report similar cases to further explore the mechanisms. An expert panel reviewed data, including video electroencephalogram (VEEG) and electrocardiogram material at the time of cardiorespiratory arrests whenever available.

FINDINGS

147 (92%) of 160 units responded to the survey. 29 cardiorespiratory arrests, including 16 SUDEP (14 at night), nine near SUDEP, and four deaths from other causes, were reported. Cardiorespiratory data, available for ten cases of SUDEP, showed a consistent and previously unrecognised pattern whereby rapid breathing (18-50 breaths per min) developed after secondary generalised tonic-clonic seizure, followed within 3 min by transient or terminal cardiorespiratory dysfunction. Where transient, this dysfunction later recurred with terminal apnoea occurring within 11 min of the end of the seizure, followed by cardiac arrest. SUDEP incidence in adult epilepsy monitoring units was 5·1 (95% CI 2·6-9·2) per 1000 patient-years, with a risk of 1·2 (0·6-2·1) per 10,000 VEEG monitorings, probably aggravated by suboptimum supervision and possibly by antiepileptic drug withdrawal.

INTERPRETATION

SUDEP in epilepsy monitoring units primarily follows an early postictal, centrally mediated, severe alteration of respiratory and cardiac function induced by generalised tonic-clonic seizure, leading to immediate death or a short period of partly restored cardiorespiratory function followed by terminal apnoea then cardiac arrest. Improved supervision is warranted in epilepsy monitoring units, in particular during night time.

FUNDING

Commission of European Affairs of the International League Against Epilepsy.