Sensitivity of Compressed Spectral Arrays for Detecting Seizures in Acutely Ill Adults

Background

Continuous EEG recordings (cEEGs) are increasingly used in evaluation of acutely ill adults. Pre-screening using compressed data formats, such as compressed spectral array (CSA), may accelerate EEG review. We tested whether screening with CSA can enable detection of seizures and other relevant patterns.

Methods

Two individuals reviewed the CSA displays of 113 cEEGs. While blinded to the raw EEG data, they marked each visually homogeneous CSA segment. An independent experienced electroencephalographer reviewed the raw EEG within 60 s on either side of each mark and recorded any seizures (and isolated epileptiform discharges, periodic epileptiform discharges (PEDs), rhythmic delta activity (RDA), and focal or generalized slowing). Seizures were considered to have been detected if the CSA mark was within 60 s of the seizure. The electroencephalographer then determined the total number of seizures (and other critical findings) for each record by exhaustive, page-by-page review of the entire raw EEG.

Results

Within each of the 39 cEEG recordings containing seizures, one CSA reviewer identified at least one seizure, while the second CSA reviewer identified 38/39 patients with seizures. The overall detection rate was 89.0 % of 1,190 total seizures. When present, an average of 87.9 % of seizures were detected per individual patient. Detection rates for other critical findings were as follows: epileptiform discharges, 94.0 %; PEDs, 100 %; RDA, 97.9 %; focal slowing, 100 %; and generalized slowing, 100 %.

Conclusions

CSA-guided review can support sensitive screening of critical pathological information in cEEG recordings. However, some patients with seizures may not be identified.     

High Risk for Seizures Following Subarachnoid Hemorrhage Regardless of Referral Bias

Background

To investigate the frequency, predictors, and clinical impact of electrographic seizures in patients with high clinical or radiologic grade non-traumatic subarachnoid hemorrhage (SAH), independent of referral bias.

Methods

We compared rates of electrographic seizures and associated clinical variables and outcomes in patients with high clinical or radiologic grade non-traumatic SAH. Rates of electrographic seizure detection before and after institution of a guideline which made continuous EEG monitoring routine in this population were compared.

Results

Electrographic seizures occurred in 17.6 % of patients monitored expressly because of clinically suspected subclinical seizures. In unselected patients, seizures still occurred in 9.6 % of all cases, and in 8.6 % of cases in which there was no a priori suspicion of seizures. The first seizure detected occurred 5.4 (IQR 2.9–7.3) days after onset of subarachnoid hemorrhage with three of eight patients (37.5 %) having the first recorded seizure more than 48 h following EEG initiation, and 2/8 (25 %) at more than 72 h following EEG initiation. High clinical grade was associated with poor outcome at time of hospital discharge; electrographic seizures were not associated with poor outcome.

Conclusions

Electrographic seizures occur at a relatively high rate in patients with non-traumatic SAH even after accounting for referral bias. The prolonged time to the first detected seizure in this cohort may reflect dynamic clinical features unique to the SAH population.     

A Prospective Observational Study of Seizures After Cardiac Surgery Using Continuous EEG Monitoring

Introduction

Recently, there have been several retrospective reports suggesting an increased frequency in seizures after cardiopulmonary bypass, associated with increased patient morbidity. We sought to prospectively investigate the incidence of electrographic seizures without clear convulsive clinical correlates and subsequent neurologic injury following cardiac surgery.

Methods

This single-center, prospective, observational study used continuous subhairline electroencephalographic (cEEG) monitoring in the intensive care unit following routine cardiac surgery, ranging from coronary bypass surgery to complex aortic arch reconstruction. The primary outcome was the proportion of patients developing postoperative seizures, as confirmed on cEEG monitoring. Secondary outcomes included neurologic injury, post-operative complications, mortality, and ICU and hospital lengths of stay.

Results

101 consenting patients were included and 3 patients had seizures (2 focal and convulsive, 1 generalized and electrographic). All three patients with seizures were ≥65 years old, had “open-chamber” procedures, and had cardiopulmonary bypass times >120 min. One of the 3 patients with seizures was exposed to higher doses of tranexamic acid. None of the patients with seizures had permanent neurologic sequelae and all were doing well at 1-year follow-up. There was no increased morbidity or mortality in patients with seizures.

Conclusions

Electrographic seizures occur infrequently after cardiac surgery and are generally associated with a good prognosis. Prophylactic cEEG monitoring is unlikely to be cost-effective in this population. (ClinicalTrials.gov Identifier: NCT01291992).     

Applicability of NeuroTrend as a bedside monitor in the neuro ICU

Objective

To assess whether ICU caregivers can correctly read and interpret continuous EEG (cEEG) data displayed with the computer algorithm NeuroTrend (NT) with the main attention on seizure detection and determination of sedation depth.

Levetiracetam Versus Phenytoin: A Comparison of Efficacy of Seizure Prophylaxis and Adverse Event Risk Following Acute or Subacute Subdural Hematoma Diagnosis

Background

Although both levetiracetam and phenytoin are used for seizure prophylaxis in subdural hematomas (SDHs), there is little data on their comparative efficacies. We compared the efficacy and risk of using levetiracetam versus phenytoin for seizure prophylaxis following acute or subacute SDH diagnosis.

Methods

In this retrospective cohort study, the clinical data registry at a tertiary care hospital was searched for all cases of acute or subacute SDHs that were admitted to hospital in 2002, 2003, or 2011. Risk of clinical and/or electrographic seizures, and risk of adverse drug events were compared between the two exposure arms.

Results

124 subjects in the phenytoin arm and 164 subjects in the levetiracetam arm were included. There was no significant difference in clinical and/or electrographic seizure risk, though there was a decreased risk of adverse events in the levetiracetam arm (p < 0.001). In subjects with midline shift >0 mm, levetiracetam was associated with an increased risk of electrographic seizures during hospitalization (p = 0.028) and a decreased risk of adverse drug effects (p = 0.001), compared with phenytoin use.

Conclusions

Levetiracetam generally appears to have a similar efficacy to phenytoin in preventing clinical and/or electrographic seizures following acute/subacute SDH diagnosis, though patients with midline shift >0 mm may have associated with a higher risk of electrographic seizures on levetiracetam compared with patients on phenytoin. Levetiracetam is associated with a lower risk of adverse drug effects. A prospective, randomized study would more definitively determine any difference in efficacy and risk between phenytoin and levetiracetam.     

Metabolic Correlates of the Ictal-Interictal Continuum: FDG-PET During Continuous EEG

Background

Ictal-interictal continuum (IIC) continuous EEG (cEEG) patterns including periodic discharges and rhythmic delta activity are associated with poor outcome and in the appropriate clinical context, IIC patterns may represent “electroclinical” status epilepticus (SE). To clarify the significance of IIC patterns and their relationship to “electrographic” SE, we investigated FDG-PET imaging as a complementary metabolic biomarker of SE among patients with IIC patterns.

Methods

A single-center prospective clinical database was ascertained for patients undergoing FDG-PET during cEEG. Following MRI-PET co-registration, the maximum standardized uptake value in cortical and subcortical regions was compared to contralateral homologous and cerebellar regions. Consensus cEEG review and clinical rating of etiology and treatment response were performed retrospectively with blinding. Electrographic SE was classified as discrete seizures without interictal recovery or >3-Hz rhythmic IIC patterns. Electroclinical SE was classified as IIC patterns with electrographic and clinical response to anticonvulsants; clonic activity; or persistent post-ictal encephalopathy.

Results

Eighteen hospitalized subjects underwent FDG-PET during contemporaneous IIC patterns attributed to structural lesions (44 %), neuroinflammatory/neuroinfectious disease (39 %), or epilepsy (11 %). FDG-PET hypermetabolism was common (61 %) and predicted electrographic or electroclinical SE (sensitivity 79 % [95 % CI 53–93 %] and specificity 100 % [95 % CI 51–100 %]; p = 0.01). Excluding electrographic SE, hypermetabolism also predicted electroclinical SE (sensitivity 80 % [95 % CI 44–94 %] and specificity 100 % [95 % CI 51–100 %]; p = 0.01).

Conclusions

In hospitalized patients with IIC EEG patterns, FDG-PET hypermetabolism is common and is a candidate metabolic biomarker of electrographic SE or electroclinical SE.

     

Effects of temporal lobectomy on consciousness-impairing and consciousness-sparing seizures in children

Purpose

Most children with medically refractory temporal lobe epilepsy (TLE) become seizure free after temporal lobectomy, but some individuals continue to seize. As studies of temporal lobectomy typically focus on seizure freedom, the effect of surgery on seizure type and frequency among children with persistent seizures is poorly understood. Seizures which impair consciousness are associated with increased morbidity compared to consciousness-sparing seizures.

Methods

A retrospective cohort study was performed to evaluate the effects of temporal lobectomy on seizure type and frequency in children with intractable TLE.

Results

Among 58 pediatric TLE patients with a mean (±SEM) age of 14.0?±?0.7 years who received temporal lobectomy, 46 (79.3 %) individuals achieved an Engel class I seizure outcome, including 38 (65.5 %) children who became completely seizure free (Engel IA). Mean follow-up was 2.7?±?0.4 years. While the number of patients experiencing simple partial seizures (SPSs) (consciousness sparing) decreased by only 23 % after surgery, the number of children having complex partial seizures and generalized tonic–clonic seizures (consciousness impairing) diminished by 87 and 83 %, respectively (p?<?0.01). SPS was the predominant seizure type in only 11.3 % of patients before resection, but in 42.1 % of patients with postoperative seizures (p?<?0.01). Children with postoperative seizures experienced a 70 % reduction in overall seizure frequency compared to baseline (p?<?0.05), having consciousness-impairing seizures 94 % less frequently (p?<?0.05), but having consciousness-sparing seizures 35 % more frequently (p?=?0.73).

Conclusions

Seizure type and frequency are important considerations in the medical and surgical treatment of children with epilepsy, although complete seizure freedom remains the ultimate goal.     

Continuous Electroencephalography (cEEG) Changes Precede Clinical Changes in a Case of Progressive Cerebral Edema

Background

Continuous electroencephalogram (cEEG) is tightly linked to cerebral metabolism and is sensitive to cerebral ischemia and hypoxia. The severity of cerebral ischemia can be seen on cEEG as changes in morphology, amplitude, or frequency, and cEEG may detect neuronal dysfunction at a reversible stage.

Methods

Case report and imaging.

Results

We present a case of focal cerebral edema with changes seen on cEEG 24 h before clinical signs of increased intracranial pressure. cEEG showed developing asymmetry in the left hemisphere followed by burst suppression. The right hemisphere showed similar progression to burst suppression. Complete suppression of both hemispheres was noted 6 h before clinical signs of herniation. Computed tomography (CT) head confirmed a large left parietal intracerebral hematoma with mass effect.

Conclusions

cEEG has applications in monitoring cerebral dysfunction in addition to detecting seizure activity in the intensive care unit. It may serve a vital role in multi-modality monitoring for early recognition of neurological complications from brain injuries that may not be noticed clinically, which is paramount to early intervention.     

Do Survivors of Acute Neurologic Injury Remember Their Stay in the Neuroscience Intensive Care Unit?

Background

Patients in medical, surgical, and trauma intensive care units (ICUs) are at risk for later development of symptoms of post-traumatic stress disorder (PTSD). Because acute brain injury can impair recall; we sought to show that neuroscience patients undergoing prolonged neuroscience ICU admission have limited memory of their ICU stay and thus are less likely to develop symptoms of PTSD.

Methods

We surveyed patients >18 years admitted for 10 days or more to our neuroscience ICU over a 10-year period.

Results

The survey response rate was 50.5 % (47/93). Forty percent (19/47) of respondents presented with coma. Recall of details of the ICU admission was limited. Fewer than 10 % of patients who required mechanical ventilation recalled being on a ventilator. Only five patients (11 %) had responses suggestive of possible post-traumatic stress syndrome. The most commonly experienced symptoms following discharge were difficulty sleeping, difficulty with concentration, and memory loss.

Conclusion

Patients requiring prolonged neuroscience ICU admission do not appear to be traumatized by their ICU stay.     

Interrater agreement in visual scoring of neonatal seizures based on majority voting on a web-based system: The Neoguard EEG database

Objective

To assess interrater agreement based on majority voting in visual scoring of neonatal seizures.

Continuous Video EEG for Patients with Acute Encephalopathy in a Pediatric Intensive Care Unit

Objectives

In this study, we aimed to determine the incidence of electrographic seizures among patients in a pediatric intensive care unit (PICU) presenting with acute encephalopathy. Risk factors and duration of continuous EEG monitoring needed to capture electrographic seizures were also assessed.

Study Design

Based on a NeuroICU clinical care pathway, all patients with acute encephalopathy admitted to the PICU are monitored with continuous video electroencephalogram (cVEEG) for 48?h or until the encephalopathy improves. Ninety-four consecutive patients included on the pathway over a year were identified. Mean age was 6.7?years (range 32?days?C17.9?years). Data pertaining to patient clinical information and electrographic seizures, including non-convulsive seizures (NCS) and non-convulsive status epilepticus (NCSE), were extracted from a prospective database.

Results

Thirty percent (28/94) had seizures captured on cVEEG including 17 patients (18?%) with NCSE. Variables associated with electrographic seizures were age <24?months and clinical seizure(s) prior to EEG placement. The first seizure captured on cVEEG occurred in the first 24?h for the majority of patients (97?%). Acute brain injury and electrographic seizures were associated with worse outcome.

Conclusions

Electrographic seizures are common in pediatric patients with acute encephalopathy. This study supports the practice of cVEEG monitoring for at least 24?h in pediatric patients with acute encephalopathy, particularly if they are less then 24?months of age and/or if a clinical event suspicious for seizure precedes the encephalopathy.     

Reduced electrode arrays for the automated detection of rhythmic and periodic patterns in the intensive care unit: Frequently tried,frequently failed?

Objective

To investigate the effect of systematic electrode reduction from a common 10-20 EEG system on pattern detection sensitivity (SEN).

The Use of Continuous EEG Monitoring in Intensive Care Units in The Netherlands: A National Survey

Background

Currently, continuous electroencephalographic monitoring (cEEG) is the only available diagnostic tool for continuous monitoring of brain function in intensive care unit (ICU) patients. Yet, the exact relevance of routinely applied ICU cEEG remains unclear, and information on the implementation of cEEG, especially in Europe, is scarce. This study explores current practices of cEEG in adult Dutch ICU departments focusing on organizational and operational factors, development over time and factors perceived relevant for abstaining its use.

Methods

A national survey on cEEG in adults among the neurology and adult intensive care departments of all Dutch hospitals (n?=?82) was performed.

Results

The overall institutional response rate was 78%. ICU cEEG is increasingly used in the Netherlands (in 37% of all hospitals in 2016 versus in 21% in 2008). Currently in 88% of university, 55% of teaching and 14% of general hospitals use ICU cEEG. Reasons for not performing cEEG are diverse, including perceived non-feasibility and lack of data on the effect of cEEG use on patient outcome. Mostly, ICU cEEG is used for non-convulsive seizures or status epilepticus and prognostication. However, cEEG is never or rarely used for monitoring cerebral ischemia and raised intracranial pressure in traumatic brain injury. Review and reporting practices differ considerably between hospitals. Nearly all hospitals perform non-continuous review of cEEG traces. Methods for moving toward continuous review of cEEG traces are available but infrequently used in practice.

Conclusions

cEEG is increasingly used in Dutch ICUs. However, cEEG practices vastly differ between hospitals. Future research should focus on uniform cEEG practices including unambiguous EEG interpretation to facilitate collaborative research on cEEG, aiming to provide improved standard patient care and robust data on the impact of cEEG use on patient outcome.

     

Acute neonatal encephalopathy and seizures recurrence: A combined aEEG/EEG study

PurposeTo evaluate amplitude-integrated EEG (aEEG) in comparison with conventional (cEEG) for the identification of electrographic seizures in neonates with acute neonatal encephalopathies.MethodsThirty-one conventional cEEG/aEEG long-term recordings from twenty-eight newborns were reviewed in order to assess the electrographic seizure detection rate and recurrence in newborns. Two paediatric neurologists and one neonatologist, blinded to the raw full array cEEG, were asked to mark any events suspected to be an electrographic seizures on aEEG. They were asked to decide if the displayed aEEG trace showed the pattern of a single seizure (SS), repetitive seizures (RS) or status epilepticus (SE). Their ability to recognize electrographic seizures on aEEG was compared to seizures identified on full array cEEG.Results25 of the 31 long-term cEEGs recordings showed electrographic seizures. The two paediatric neurologists and the neonatologist identified SE in 100% of the reviewed traces using aEEG alone while they identified 49.4% and 37.5% of electrographic seizures using aEEG alone. Overall, the correct identification ranged from 23.5% to 30.7% for SS and 66% for RS. The inter-observer agreement (k) for the identification of SE for the two paediatric neurologists and the neonatologist was 1.0. Overall the inter-observer agreement (k) for the detection of SS, RS and SE of the two paediatric neurologists was 0.91.ConclusionsIn our study the observers identified SE in 100% of the reviewed traces using raw aEEG alone, thus aEEG might represent a useful tool to detect SE in the setting of NICU. SS may not be reliably identified using aEEG alone. Simultaneous recording of the raw cEEG/aEEG provides a good level of sensitivity for the detection of neonatal electrographic seizures.     

Impact of Prolonged Periodic Epileptiform Discharges on Coma Prognosis

Background

Periodic epileptiform discharges (PEDs) are a frequent finding in comatose patients undergoing continuous EEG (cEEG) monitoring, but their clinical significance is unclear. PET and SPECT studies indicate that PEDs can be associated with focal hypermetabolism and hyperemia, suggesting that in some cases this pattern may be ictal and potentially harmful. We hypothesized that frequent PED activity in comatose patients is associated with reduced likelihood of recovery of consciousness.

Methods

We identified all comatose patients treated in the Columbia neuro-ICU between June 2008 and August 2009 who underwent ten or more consecutive days of video cEEG monitoring (N?=?67), and classified them into three groups: those with (1) prolonged PEDs (five or more consecutive days), (2) intermittent PEDs (at least one but fewer than five consecutive days), and (3) no PEDs. Outcome at discharge was assessed by the Glasgow Outcome Scale and classified as dead (GOS 1), vegetative (GOS 2), and command-following (GOS 3?C5).

Results

Mean age was 56?years, mean admission Glasgow Coma Scale score was seven, and the median duration of cEEG monitoring was 18 (range 10?C111) days. The most common diagnoses were hypoxic-ischemic encephalopathy (18?%), subarachnoid hemorrhage (16?%), epilepsy (15?%), encephalitis (15?%), metabolic encephalopathy (13?%), and intracerebral hemorrhage (12?%). 37?% of patients (N?=?25) had prolonged PEDs, 31?% (N?=?21) had intermittent PEDs, and 31?% (N?=?21) had no PEDs. Prolonged PEDs were associated with the presence of SIRPIDS (P?=?0.009), electrographic seizures (P?=?0.019), and number of AEDs administered (P?Conclusion Persistent spontaneous PED activity in comatose patients is associated with SIRPIDs and electrographic seizures, but has no impact on the likelihood of survival or recovery of consciousness.     

The surgical management of pediatric brain tumors causing epilepsy: consideration of the epileptogenic zone

Objective

Children suffering from epilepsy with suspected low-grade tumors may benefit from a surgical approach that considers the epileptogenic zone, which can be more extensive than the tumor region. This study aimed to determine the prevalence of epilepsy in children undergoing supratentorial tumor resection and the factors predictive of postoperative seizure freedom in children with low-grade tumors.

Methods

Subjects 3 months to 21 years undergoing supratentorial brain tumor resection between 2007 and 2011 were included in this retrospective study. Children with supratentorial, cortically based tumors and a preoperative diagnosis of epilepsy were considered epilepsy surgery candidates. Pre- and postoperative MRI were reviewed and scored for extent of resection, adjacent dysplasia, and remaining abnormal cortex postoperatively.

Results

The prevalence of seizures in all cases of supratentorial tumors was 46/87 (53 %). Eighteen were epilepsy surgery candidates. Eight of 18 (44 %) were seizure-free postoperatively with a mean follow-up of 39 months. Children who were seizure free postoperatively had tried fewer anticonvulsants than those with continued seizures (1.7 v. 2.9, p?=?0.01). Presurgical evaluation was nonstandardized, and a more extensive workup and resection were performed in children who continued to have seizures postoperatively.

Conclusions

All epilepsy surgery candidates had low-grade tumors on histological evaluation, indicating that a surgical approach that takes into consideration the epileptogenic zone is reasonable in this population. Gross total resection should be the goal, with additional attention to resection of the epileptogenic zone when located in the noneloquent cortex.     

Pediatric temporal low-grade glial tumors: epilepsy outcome following resection in 48 children

Purpose

This paper summarizes our experience with surgical treatment of pediatric low-grade glial temporal lobe tumors focusing on the long-term outcome of seizures and identifying factors associated with seizure control and failure.

Methods

We reviewed all medical records of pediatric patients that underwent temporal lobe surgery due to seizures at our institution between 1997 and 2009. Only patients with temporal lobe tumors were included in this series. The files were retrospectively reviewed for seizure history. All children had undergone pre- and postoperative evaluation, neurological examination, EEG, and MRI.

Results

The cohort includes 48 children with mean follow-up time of 5.15?years (1?C12?years). The mean age at surgery was 8.2?years (1?C18.1) and the mean seizure duration until surgery was 2.6?years. All lesions in the cohort were low-grade tumors; pilocytic astrocytoma was the most common (41%). Eighty-three percent of the patients were classified as Engel class I following surgery. There was no correlation between Engel score and the preoperative epilepsy duration, age of seizure onset or type of seizures, and pathology. The surgical complication rate was 4.1% (2/48).

Conclusions

Surgical treatment for seizure control in children and adolescents with low-grade temporal tumors provides excellent long-term results.     

Management des Status epilepticus im Kindesalter

Background

Status epilepticus (SE) in children is not frequent but life-threatening. The prognosis depends on the etiology and duration of SE; therefore, prompt diagnostics and therapy are necessary.

Material and methods

A questionnaire on the current management of SE was sent to all pediatric clinics and departments in Germany.

Results

Of the 368 questionnaires sent out a total of 30 were returned (8?%). There was a non-uniform definition of SE. Therapy protocols existed in most cases (86?%). For enteral use rectal diazepam (87?%) was preferred as first choice and buccal lorazepam (40?%) was the second choice. Of the responders 31?% would give more than 2 doses of benzodiazepines. For parenteral use diazepam (50?%) and lorazepam (47?%) were ranked first and the second choice was phenobarbital (40?%). Antiepileptic drugs were given at an interval of more than 5 min in 57?%. Valproate and levetiracetam were non-uniformly infused. In the intensive care unit (ICU) midazolam (83?%) was the medication of choice and thiopental (50?%) the first alternative. Primary therapeutic targets were no clinical seizures (83?%), no electrographic seizures (33?%), burst-suppression pattern (16?%) and complete electroencephalogram (EEG) suppression (6?%). Physicians treated focal SE and absence status differently from generalized tonic-clonic SE in 63?% and 43?% would use enteral or immune therapy during ICU treatment. A ketogenic diet was possible in 53?% of hospitals. In 87?% of the ICUs SE was treated together with neuropediatricians. Magnetic resonance imaging (MRI) was available in all units, continuous EEG (cEEG) in 50?% and amplitude integrated EEG (aEEG) in 66?%. Neuronal antibodies as a possible cause of SE was known to 60?% of responders.

Conclusion

The response rate was low. Responses to definition, diagnostics and therapy of SE were not uniform. It was therefore concluded that multicenter studies and changes in current management are urgently needed to improve the prognosis of SE in childhood.     

Does early postoperative drug regimen impact seizure control in patients undergoing temporal lobe resections?

Objective

To evaluate the impact of postoperative antiepileptic drug (AED) load on seizure control in patients who underwent surgical treatment for pharmacoresistant mesiotemporal lobe epilepsy during the first two postoperative years.

Patients and methods

532 consecutive patients (48.7% males and 51.7% females) who underwent surgical treatment for mesiotemporal lobe epilepsy were retrospectively evaluated regarding effects of AED load on seizures control during the first 2 years following epilepsy surgery. We analyzed whether postoperative increases in postoperative AED load are associated with better seizure control in patients initially not seizure free, and if postoperative decreases in postoperative AED load would increase the risk for seizure persistence or recurrence. For statistical analyses, Fisher’s exact and Wilcoxon test were applied.

Results

68.9, 64.0 and 59.1% of patients were completely seizure free (Engel Ia) at 3, 12 and 24 months after surgery, respectively. Patients in whom daily drug doses were increased did not have a higher rate of seizure freedom at any of the three follow-up periods. Of 16 patients achieving secondary seizure control at 12 months after surgery, only one did so with an increase in drug load in contrast to 15 patients who experienced a running down of seizures independent of drug load increases. Decreases in drug load did not significantly increase the risk for seizure recurrence. Of postoperatively seizure free patients at 3 months after surgery in whom AED were consequently reduced, 85% remained completely seizure free at 1 year and 76% at 1 year after surgery, respectively, as opposed to 86% each when AED was not reduced (differences n.s.). Mean daily drug load was significantly lower in seizure free patients at 12 and 24 months compared to patients with ongoing seizures.

Conclusion

In this large patient cohort stratified to the epilepsy syndrome neither did a postoperative reduction in drug load significantly increase the risk for seizure relapse nor did increases in drug dosages lead to improved seizure control. Mean drug load was on average lower in seizure free- than non-seizure free patients at 12 and 24 months of follow-up. Secondary seizure control after initial postoperative seizures in > 90% of cases occurred as a running down, independent of an AED increase. Thus, the effect of the surgical intervention rather than the postoperative drug regimen was the key determinant for seizure control. This finding supports a curative role of temporal lobe surgery rather than an effect rendering the majority of patients’ pharmacoresponsive with a critical role of the antiepileptic drug regime for seizure control.

     

The Prognostic Value of 48-h Continuous EEG During Therapeutic Hypothermia After Cardiac Arrest

Background

The aim of this study was to evaluate the prognostic value of continuous electroencephalogram (cEEG) during the first 48 h following cardiac arrest (CA) in patients treated with targeted temperature management (TTM).

Methods

We reviewed data from 92 comatose post-CA patients over a 6 year-period; cEEG recordings were performed during TTM and restoration of normothermia. EEG findings were divided into four time-periods: 0–8, 8–16, 16–24, and 24–48 h after CA. Background EEG findings were defined as moderate encephalopathy (diffuse slowing with reactivity/variability), severe encephalopathy (diffuse slowing without reactivity/variability), burst suppression or suppression, and dichotomized as malignant (suppression/burst suppression/severe encephalopathy) or benign (moderate encephalopathy). Epileptiform activity was defined as the presence of seizures, sporadic epileptiform discharges, or periodic discharges. Neurological outcome was assessed at 3 months using the cerebral performance categories (CPC) score (good outcome: CPC 1–2).

Results

26/92 (28 %) patients had a good outcome. Malignant patterns were associated with a poor outcome at all time-points, with a high positive predictive value (94–97 %) but a poor negative predictive value (44–56 %). Epileptiform activity did not influence the prognostic value of EEG patterns. All patients with moderate encephalopathy and seizures or generalized periodic discharges had a poor outcome.

Conclusions

cEEG can identify patients with poor outcome from the first hours following CA, with limited predictive value for good outcome. Epileptiform activity did not improve the prognostic accuracy of EEG, but seizures and generalized periodic discharges were associated with poor outcome even when developing on a benign EEG pattern.