Persistent nonconvulsive status epilepticus after the control of convulsive status epilepticus

Treatment of Nonconvulsive Status Epilepticus

Nonconvulsive status epilepticus (NCSE) is relatively common; it comprises at least one third of all cases of status epilepticus. NCSE may be an even more common, yet more elusive, condition in the elderly population. NCSE can be divided into complex partial status epilepticus (CPSE), NCSE in coma, and typical absence status epilepticus (TAS). The clinical manifestations may be subtle, and thus the diagnosis of these conditions is critically dependent on electroencephalography (EEG). When EEG demonstrates typical ictal patterns, the diagnosis is usually straightforward. However, in many circumstances the EEG pattern has to be differentiated from other encephalopathic patterns, and this differentiation can prove troublesome; clinical and electrographic response to treatment can prove helpful in these situations. The prognosis for NCSE in the elderly is generally poor due to the underlying etiology rather than the persistence of electrographic discharges. Whether the neuronal damage that occurs in convulsive status epilepticus and in animal models of limbic status epilepticus also occurs in NCSE in humans is still a matter of debate. Intravenous treatment is not benign, especially in the elderly, who may be at greater risk of systemic complications from hypotensive and sedative agents. Therefore, a more conservative approach to the treatment of NCSE in the elderly is warranted. Oral benzodiazepines should be used for the treatment of TAS and CPSE in noncomatose patients with a prior history of epilepsy, and in some circumstances, intravenous medication may be necessary. Generally, anesthetic coma should not be advised in either of these conditions. A more aggressive approach may be required with NCSE in coma, in the hope of improving a very poor prognosis. Treatment regimens will remain largely speculative until there are more relevant animal models and controlled trials of conservative versus aggressive treatment.

Epidemiology and outcomes of status epilepticus in the elderly

Status epilepticus (SE) is a serious condition of prolonged or repetitive seizures. The annual incidence (86/100,000) of SE in the elderly who are aged 60 and greater is almost twice that of the general population and is even higher in those who are 70 years and older. Either acute or remote symptomatic stroke causes approximately 60% of SE seen in the elderly. SE is associated with a high mortality in the elderly (38%), with a rate approaching 50% in patients older than 80 years of age. Etiology is a strong determinant of mortality in the elderly: mortality approaches 100% in patients with anoxia and 30% in patients with either metabolic disorders, hemorrhages, tumors, or systemic infections. Mortality is almost three times higher in SE associated with acute ischemic stroke than in stroke alone, indicating synergistic effects. Duration of SE is also a factor in mortality. Treatment should be initiated for any convulsive seizure that lasts at least 10 min or is repetitive. An electroencephalogram (EEG) should be promptly obtained so that a diagnosis can be made without delay. Because older patients have a greater likelihood of nondiagnostic findings on routine EEGs, prolonged EEG recordings and inpatient video-EEG monitoring significantly increase the rate of establishing a definitive diagnosis. Nonconvulsive status epilepticus in the elderly is especially difficult to diagnose and should be evaluated with an EEG. Treatment of SE is complicated by altered pharmacokinetics in the elderly. Initial treatments, usually the administration of an intravenous benzodiazepine, have overall success rates of 55% for overt convulsive SE and 14.9% for subtle SE. For refractory SE, little is gained by using additional standard drugs, and general anesthesia with continuous EEG monitoring is recommended.

Generalised convulsive status epilepticus: an overview

Generalised convulsive status epilepticus is one of the most common emergencies encountered in clinical practice. This review discusses the recent understanding of this life-threatening condition with reference to the definition, pathophysiology, evaluation, complications, refractory status and prognosis. Besides epilepsy, other neurological and medical illnesses could be associated with status epilepticus. The goals of management and pharmacological approach are outlined, considering the available evidence. Prompt recognition and timely intervention, including pre-hospital treatment, are therapeutically beneficial. Refractory status should be managed in intensive care units under close monitoring. More evidence is needed for evolving the optimal treatment. A suitable treatment protocol would guide in avoiding the pitfalls at various points along the management pathway.

Nonconvulsive status epilepticus in children: clinical and EEG characteristics

BACKGROUND

Nonconvulsive status epilepticus (NCSE) is a highly heterogeneous clinical condition that is understudied in the pediatric population.

OBJECTIVE

To analyze the epidemiological, clinical, and electroencephalograpic features in pediatric patients with NCSE.

METHODS

We identified 19 pediatric patients with NCSE from the epilepsy database of the Comprehensive Epilepsy Center at, Columbia University between June 2000 and December 2003. Continuous electroencephalographic (EEG) monitoring was analyzed and chart review was performed.

RESULTS

The patients ranged from 1 month old to 17 years of age. Five patients developed NCSE following convulsive status epilepticus (CSE), and a further 12 patients developed NCSE after brief convulsions. Two developed NCSE as the first manifestation during a comatose state following hypoxic events. Acute hypoxic-ischemic injury was the most frequent etiology of NCSE in our population (5 of 19; 26%), followed by exacerbation of underlying neurometabolic disease (4 of 19; 21%), acute infection (3 of 19; 16%), change in antiepileptic drug regimen (3 of 19;16%), refractory epilepsy (2 of 19; 11%) and intracranial hemorrhage (2 of 19; 11%). Six patients had associated periodic lateralized epileptiform discharges (PLEDs), one had generalized periodic epileptiform discharges (GPEDs). Five (5 of 19; 26%) patients died of the underlying acute medical illness. Periodic discharges were associated with worse outcome.

CONCLUSION

The majority of our patients with NCSE had preceding seizures in the acute setting prior to the diagnosis of NCSE, though most of these seizures were brief, isolated convulsions (12 patients) rather than CSE (five patients). Prolonged EEG monitoring to exclude NCSE may be warranted in pediatric patients even after brief convulsive seizures. Prompt recognition and treatment may be necessary to improve neurological outcome.

Evaluation of gabapentin and ethosuximide for treatment of acute nonconvulsive seizures following ischemic brain injury in rats

Acute seizures following brain injury have been associated with a worsening of patient outcome, but they are often undiagnosed and untreated when they occur without motor convulsions. Here, we sought to compare the antiseizure profile of ethosuximide (EXM; 125-312.5 mg/kg i.v.) and gabapentin (GBP; 0.3-50 mg/kg. i.v.) in a rat model of nonconvulsive seizures (NCS) induced by brain ischemia. Seizures were detected by continuous electroencephalographic monitoring for 24 h following permanent middle cerebral artery occlusion (MCAo). Both "preseizure" and "postseizure" treatment effects were evaluated. Control rats experienced a 91% incidence of NCS (averaging 10-11 NCS/rat), which was significantly reduced following preseizure treatment (delivered 20 min post-MCAo) with either EXM (ED(50) = 161 mg/kg) or GBP (ED(50) = 10.5 mg/kg). In contrast to preseizure treatment effects, only GBP reduced NCS when given after the first seizure event. A further, albeit nonsignificant, 20% reduction in NCS incidence was measured when given in combination postseizure. Drug treatment also reduced infarct volume, which was positively correlated to the number of NCS events (r = 0.475; P < 0.001). EXM and GBP treatment of cultured neurons exposed to neurotoxic or ischemic insults showed no neuroprotective effects, suggesting that in vivo neuroprotection can be attributed to anti-seizure effects. We conclude that EXM and GBP significantly attenuate NCS in a dose-related manner and may help to improve patient outcome from brain ischemia-induced seizure activity.

Nonconvulsive Seizures in the Pediatric Intensive Care Unit: Etiology, EEG, and Brain Imaging Findings

PURPOSES

To determine the occurrence of nonconvulsive seizures (NCS) in the Pediatric Intensive Care Unit (PICU); to ascertain the relationship of NCS to past medical history, etiology, EEG, and brain imaging; and to determine the concordance between abnormal EEG findings and neuroimaging abnormalities.

METHODS

A retrospective review was conducted of all pediatric patients who were admitted or transferred to the PICU from January 2000 to December 2003 with an unexplained decrease in level of consciousness, no overt clinical seizures, and EEG recordings performed within the 24 h of onset of an altered state of consciousness.

RESULTS

Twenty-three of 141 patients who met criteria for inclusion in the study (16.3%) were found to have NCS. The male to female ratio was 1.9:1. The largest group of patients (43%) had no preexisting neurological condition prior to the onset of NCS. In the remainder, the etiology of NCS included: acute structural brain lesion (48%), acute nonstructural brain lesion (22%), epilepsy-related seizure (13%), and others (17%). Epileptic foci were lateralized to the right side in 39.2%, the left side in 30.4%, and were bilateral in 30.4%. Of 23 patients with NCS, 18 (78.3%) demonstrated abnormal neuroimaging. In 10 of 18 of these patients (55.6%), the findings on neuroimaging were concordant with the lateralization found on EEG (p < 0.05, Fisher's exact test).

CONCLUSIONS

NCS are not uncommon in pediatric patients with an altered state of consciousness. Almost half of the patients were previously healthy especially if they were under 6 months of age. This report highlights the importance of clinical awareness of NCS in the PICU.

[Refractory status epilepticus: diagnosis, therapy, course, and prognosis]

Status epilepticus (SE) is a frequent neurological emergency with an annual incidence of 10-20/100,000 individuals. The overall mortality is about 10-20%. Patients present with long-lasting fits or series of epileptic seizures or extended stupor and coma. Furthermore, patients with SE can suffer from a number of systemic complications possibly also due to side effects of the medical treatment. In the beginning, standardized treatment algorithms can successfully stop most SE. A minority of SE cases prove however to be refractory against the initial treatment and require intensified pharmacologic intervention with nonsedating anticonvulsive drugs or anesthetics. In some partial SE, nonpharmacological approaches (e.g., epilepsy surgery) have been used successfully. This paper reviews scientific evidence of the diagnostic approach, therapeutic options, and course of refractory SE, including nonpharmacological treatment.

Prognostic significance of continuous EEG monitoring in patients with poor-grade subarachnoid hemorrhage

INTRODUCTION

Predicting outcome in patients with poor-grade subarachnoid hemorrhage (SAH) may help guide therapy and assist in family discussions. The objective of this study was to determine if continuous electroencephalogram (cEEG) monitoring results are predictive of 3-month outcome in critically ill patients with SAH.

METHODS

We prospectively studied 756 patients with SAH over a 7-year period. Functional outcome was assessed at 3 months with the modified Rankin Scale (mRS). Patients that underwent cEEG monitoring were retrospectively identified and EEG findings were collected. Multivariate logistic regression analysis was performed to identify EEG findings associated with poor outcome, defined as mRS 4 to 6 (dead or moderately to severely disabled).

RESULTS

In 116 patients with SAH, cEEG monitoring and 3-month mRS were available. Of these patients, 88% had a Hunt & Hess grade of 3 or worse on admission. After controlling for age, Hunt & Hess grade, and presence of intraventricular hemorrhage on admission CT scan, poor outcome was associated with the absence of sleep architecture (80 versus 47%; odds ratio [OR] 4.3, 95%-confidence interval [CI] 1.1-17.2) and the presence of periodic lateralized epileptiform discharges (PLEDS) (91 versus 66% OR 18.8, 95%-CI 1.6-214.6). In addition, outcome was poor in all patients with absent EEG reactivity (n = 8), generalized periodic epileptiform discharges (n = 12), or bilateral independent PLEDs (n = 5), and in 92% (11 of 12) of patients with nonconvulsive status epilepticus.

CONCLUSIONS

cEEG monitoring provides independent prognostic information in patients with poor-grade SAH, even after controlling for clinical and radiological findings. Unfavorable findings include periodic epileptiform discharges, electrographic status epilepticus, and the absence of sleep architecture.

Future of brain support: multimodality monitoring

Multimodality monitoring of cerebral physiology encompasses the application of different monitoring techniques and integration of several measured physiological and biochemical variables into the assessment of brain metabolism, structure, perfusion and oxygenation status, in addition to clinical evaluation. Novel monitoring techniques include transcranial Doppler ultrasonography, neuroimaging, intracranial pressure, cerebral perfusion and cerebral blood flow monitors, brain tissue oxygen tension monitoring, microdialysis, evoked potentials and continuous electroencephalography. Multimodality monitoring enables the immediate detection and prevention of acute neurological events, as well as appropriate intervention based on a patient’s individual disease state in the neurocritical care unit. Simultaneous real-time analysis of cerebral physiological, metabolic and cardiovascular parameters has broadened knowledge regarding complex brain pathophysiology and cerebral hemodynamics. Integration of this information allows for a more precise diagnosis and optimization of management of patients with brain injury.

Status epilepticus: pathophysiology and management in adults

As in Clark and Prout's classic work, we identify three phases of generalised convulsive status epilepticus, which we call impending, established, and subtle. We review physiological and subcellular changes that might play a part in the transition from single seizures to status epilepticus and in the development of time-dependent pharmacoresistance. We review the principles underlying the treatment of status epilepticus and suggest that prehospital treatment is beneficial, that therapeutic drugs should be used in rapid sequence according to a defined protocol, and that refractory status epilepticus should be treated with general anaesthesia. We comment on our preference for drugs with a short elimination half-life and discuss some therapeutic choices.

Beta Activity in Status Epilepticus

Focal beta activity on scalp EEG is a rare seizure pattern that has most extensively been studied in patients undergoing evaluation for epilepsy surgery. However, ictal beta activity is uncommon beyond this population and has not been reported in human status epilepticus. We observed ictal focal beta activity as the predominant seizure pattern in a patient with refractory status epilepticus. Continuous left temporal beta activity clinically correlated with complex partial semiology on video-EEG.

Treatment of seizure emergencies: Convulsive and non-convulsive status epilepticus

Status epilepticus (SE), defined as recurrent epileptic seizures without complete recovery between seizures, is one of the most serious manifestations of epilepsy. Generalized convulsive status epilepticus (GCSE) is the most common and most life-threatening form of SE, and aging increases the mortality risk. In a recent study of treatment of GCSE, 226 of 518 evaluable patients (43.6%) were of age 65 or older. In the 157 elderly patients with overt GCSE, phenobarbital was successful as first-line treatment in 71.4%, lorazepam in 63%, diazepam and phenytoin in 53.3%, and phenytoin alone in 41.5%. Phenobarbital and lorazepam were more successful than phenytoin alone. In the 69 elderly patients with subtle GCSE, success as the first treatment was 30.8% for phenobarbital, 14.3% for lorazepam, 11.8% for phenytoin, and 7.7% for diazepam and phenytoin. Overall, the results were similar to those reported for the entire study. Lorazepam, because of ease of use, is probably the best drug for the initial treatment of overt GCSE in the elderly; phenobarbital may be the best drug for subtle GCSE in this group, but more data are needed. The term "nonconvulsive SE" has been used to include complex partial SE and absence SE - both of which present as an "epileptic twilight state" - and SE in comatose patients. The diagnosis can be challenging, particularly in the elderly, as overlapping clinical features and electroencephalogram patterns can be seen in SE and in a variety of encephalopathic conditions. There is a suggestion that aggressive treatment of elderly patients with nonconvulsive SE may worsen prognosis. Clearly, there is a need for more data to better understand management of elderly patients with both convulsive and nonconvulsive SE.

The interpretation of the EEG in stupor and coma

This review discusses a variety of causes of stupor and coma and associated electroencephalographic (EEG) findings. These include metabolic disturbances such as hepatic or renal dysfunction, which are often characterized by slowing of background rhythms and triphasic waves. Hypoxia and drug intoxications can produce a number of abnormal EEG patterns such as burst suppression, alpha coma, and spindle coma. Structural lesions, either supra- or infratentorial, are reviewed. EEGs in the former may show focal disturbances such as delta and theta activity, epileptiform abnormalities, and attenuation of faster frequencies. In infratentorial lesions, the EEG may appear normal, particularly with a pontine lesion. Some patients may be encephalopathic because of ongoing epileptic activity with minimal or no motor movements. This entity, nonconvulsive status epilepticus (NCSE), is difficult to diagnose in obtunded/comatose patients, and an EEG is required to verify the diagnosis and to monitor treatment. Several EEG patterns and their interpretation in suspected cases of NCSE such as periodic lateralized epileptiform discharges (PLEDs), bilateral independent periodic lateralized epileptiform discharges (BIPLEDs), generalized periodic epileptiform discharges (GPEDs), and triphasic waves are reviewed. Other entities discussed include the locked-in syndrome, neocortical death, persistent vegetative state, brainstem death, and brain death.

Refractory generalised convulsive status epilepticus : a guide to treatment

The patient with status epilepticus has continuous or rapidly repeating seizures. Generalised convulsive status epilepticus (GCSE) is the most common form of the disorder and is a life-threatening condition that requires prompt medical management. Status epilepticus that does not respond to first-line benzodiazepines (lorazepam or diazepam) or to second-line antiepileptic drugs (phenytoin/fosphenytoin, phenobarbital or valproate) is usually considered refractory and requires more aggressive treatment. The optimal treatment of refractory GCSE has not been defined, but patients should be treated in an intensive care unit, as artificial ventilation and haemodynamic support are required. Invasive haemodynamic monitoring is often necessary and EEG monitoring is essential. The drug treatment of refractory GCSE involves general anaesthesia with continuous intravenous anaesthetics given in doses that abolish all clinical and electrographic epileptic activity, often requiring sedation to the point of burst suppression on the EEG. Barbiturate anaesthetics, pentobarbital in the US and thiopental sodium in Europe and Australia, are the most frequently used agents and are highly effective for refractory GCSE both in children and adults. Indeed, they remain the only way to stop seizure activity with certainty in severely refractory cases. Other options are midazolam for adults and children and propofol for adults only.Regardless of the drug selected, intravenous fluids and vasopressors are usually required to treat hypotension. Once seizures have been controlled for 12-24 hours, continuous intravenous therapy should be gradually tapered off if the drug being administered is midazolam or propofol. Gradual tapering is probably not necessary with pentobarbital or thiopental sodium. Continuous EEG monitoring is required during high-dose treatment and while therapy is gradually withdrawn. During withdrawal of anaesthetic therapy, intravenous phenytoin/fosphenytoin or valproate should be continued (these agents having been administered during earlier phases of GCSE) to ensure an adequate baseline of antiepileptic medication so as to prevent the recurrence of status epilepticus. If additional medication is needed, the most appropriate antiepileptic drugs are gabapentin for focal seizures and levetiracetam and topiramate for all seizure types, as these drugs can be started at high doses with a low risk of idiosyncratic reactions. Even with current best practice, mortality in patients who experience refractory GCSE is about 50% and only the minority return to their premorbid functional baseline. Therefore, new treatment options are urgently needed. The ideal new drug for refractory GCSE would be one that has the ability to stop seizures more effectively and safely than current drugs, and that has neuroprotective properties to prevent the brain damage and neurological morbidity caused by GCSE.

Prolonged refractory status epilepticus following acute traumatic brain injury: a case report of excellent neurological recovery

Introduction

Refractory status epilepticus (RSE) secondary to traumatic brain injury (TBI) may be under-recognized and is associated with significant morbidity and mortality.

Methods

This case report describes a 20 year old previously healthy woman who suffered a severe TBI as a result of a motor vehicle collision and subsequently developed RSE. Pharmacological coma, physiological support and continuous electroencephalography (cEEG) were undertaken.

Results

Following 25 days of pharmacological coma, electrographic and clinical seizures subsided and the patient has made an excellent cognitive recovery.

Conclusion

With early identification, aggressive physiological support, appropriate monitoring, including cEEG, and an adequate length of treatment, young trauma patients with no previous seizure history and limited structural damage to the brain can have excellent neurological recovery from prolonged RSE.

Continuous EEG monitoring in comatose intensive care patients: epileptiform activity in etiologically distinct groups

INTRODUCTION

It is unclear whether patients or subpopulations of patients might benefit from EEG monitoring.

METHODS

We conducted a prospective trial of continuous electroencephalogram monitoring (CEEG; 48 hours).

RESULTS

Eleven of 55 (20%) patients who underwent CEEG monitoring recorded seizures. Of patients with acute structural brain lesions (ASBLs), 10 of 31 (32%) patients experiences recorded seizures, whereas only 24 (4%) patients with metabolic encephalopathies experienced recorded seizures (p < 0.01). Six patients with ASBLs (11%) and one patient with metabolic encephalopathy (4%) had spikes/interictal epileptiform discharges (p = 0.087).

CONCLUSION

Our study suggests that CEEG monitoring may be more valuable for detection of seizures in patients with ASBLs than in patients with metabolic encephalopathies.

Nonconvulsive status epilepticus: clinical features and diagnostic challenges

NCSE, once thought to be a rare disorder, should be considered in any patient presenting with an alteration in mental status of indeterminate cause. The psychiatrist needs to be aware of the different clinical characteristics of this disorder as well as similarities and differences from psychiatric disorders. A history of seizure is not necessary for the diagnosis, nor is motor activity necessarily associated with NCSE. An EEG is required to confirm the diagnosis and should be performed when possible, because early recognition and treatment may improve outcome. There is usually a good response to an intravenous benzodiazepine; when response has been delayed, other anticonvulsants have been used as adjuncts. The EEG is necessary to distinguish AS from CPS so that, when indicated, the proper long-term antiepileptic drug therapy can be started. Although NCSE has been described in the literature for many years, there is still a great need for carefully designed prospective studies to help define clear guidelines to assist in clinical and management decision making and, ultimately, to improve outcomes.

Continuous electroencephalogram monitoring in critically ill patients

The past few years have witnessed remarkable advances in continuous EEG monitoring (cEEG). The indications and applications for cEEG are broadening, including detection of nonconvulsive seizures, spell characterization, and prognostication. Seizures are common in the critically ill, are usually nonconvulsive, and can easily be missed without cEEG. Interpretation and clinical management of the complex periodic and rhythmic EEG patterns commonly identified in these patients require further study. With the use of quantitative analysis techniques, cEEG can detect cerebral ischemia very early, before permanent neuronal injury occurs. This article reviews the indications and recent advances in cEEG in critically ill patients. Continuous brain monitoring with cEEG is rapidly becoming the standard of care in critically ill patients with neurologic impairment.

Treatment of convulsive and nonconvulsive status epilepticus

Status epilepticus (SE) should be treated as quickly as possible with full doses of medications as detailed in a written hospital protocol. Lorazepam is the drug of choice for initial treatment. If intravenous access is not immediately available, then rectal diazepam or nasal or buccal midazolam should be given. Prehospital treatment of seizures by emergency personnel is effective and safe, and may prevent cases of refractory SE. Home treatment of prolonged seizures or clusters with buccal, nasal, or rectal benzodiazepines should be considered for all at-risk patients. Nonconvulsive SE is underdiagnosed. An electroencephalogram should be obtained immediately in anyone with unexplained alteration of behavior or mental status and after convulsive SE if the patient does not rapidly awaken. Delay in diagnosis of SE is associated with a worse outcome and a higher likelihood of poor response to treatment. For refractory SE, continuous intravenous midazolam and propofol (alone or in combination) are rapidly effective. Randomized trials are needed to determine the best treatment for SE after lorazepam.

Postneonatal epilepsy following amplitude-integrated EEG-detected neonatal seizures

To assess the incidence of postneonatal epilepsy in term infants treated with antiepileptic drugs for neonatal seizure discharges that were detected with amplitude-integrated electroencephalography (aEEG), 206 term infants were monitored using this modality. They received antiepileptic drugs for clinical as well as subclinical neonatal seizures. Follow-up data were analyzed for the development of postneonatal epilepsy and for their neurodevelopmental outcome, assessed at 3, 9, 18 months, and 3 and 5 years of age. A total of 169 (82%) neonates received two or more antiepileptic drugs. Overall mortality was 39% (n = 80). Forty-one of the 126 survivors (33%) were abnormal at follow-up, and 12 of them developed postneonatal epilepsy (9.4%). Eighty-four children survived after hypoxic-ischemic encephalopathy grade II (n = 92), and 6 (7%) developed postneonatal epilepsy. In this subgroup, no postneonatal epilepsy was observed if seizures were controlled within 48 hours after birth and when not more than two antiepileptic drugs were required. Twenty-four children survived after an intracranial hemorrhage (n = 28), and only 1 (4%) developed postneonatal epilepsy. Eleven children survived after perinatal arterial stroke (n = 13), and 2 (18%) developed postneonatal epilepsy. In conclusion, the incidence of postneonatal epilepsy after treatment of clinical and subclinical neonatal seizures detected with continuous amplitude-integrated electroencephalography was 9.4%; This figure is lower than previously reported in children who only received treatment for clinical seizures.

Continuous electroencephalogram monitoring in the critically ill

The use of continuous electroencephalogram (cEEG) monitoring in the intensive care unit is becoming more widespread, with improvements in data storage capability and networking and the increasing awareness of nonconvulsive seizures. Current and potential uses for this technology include seizure detection, ischemia detection, and prognostication. Nonconvulsive seizures are common in the critically ill, particularly those with acute brain injury and those who are comatose. The implications of some of the electrographical patterns observed in critically ill patients are not yet clear. This article discusses findings with cEEG to date, pitfalls in performing and interpreting these studies, and where we should turn our attention with this underutilized brain monitoring technique.

Place de l’EEG dans l’épilepsie

Diagnosis of epilepsy is based upon clinical data. But the electroencephalogram (EEG) remains absolutely necessary for proper management of epileptic patients by the neurologist both in consultation and in hospital practice. Nevertheless, it is very important to keep in mind the actions limit of EEG, especially its sensitivity and specificity. In this paper, we will emphasize the value of EEG in epilepsy, its interest for the management of patients in consultation, the situations when the neurologist can use EEG-monitoring, and what it can bring to the emergency management of epileptic patients in hospital. We will thus see that, in each of these situations, EEG must be interpreted with full knowledge of clinical data.

Emergent electroencephalogram in the intensive care unit: indications and diagnostic yield

Our aim was to study the frequency and reasons an emergent electroencephalogram (EmEEG) is ordered in the ICUs compared to the hospital ward, examine its usefulness and find predictive variables for its results. We retrospectively identified all electroencephalograms ordered between December 1997 and March 2002 and performed within 1 hour. The tests ordered from four ICUs were compared with those ordered from the Ward beds, and predictive models were developed for the results based on clinical variables. We also compared the EmEEGs ordered by the Neuro-ICU to those from the other Units. The ICUs ordered 129 (49.4%) of all EmEEGs during the study period. The NICU ordered 32 tests. The most frequent reason for obtaining the test was to rule out status epilepticus (68.2%). The NICU ordered more frequently the test to exclude non-convulsive status than the other ICUs. Compared to non-ICU, ICU patients with head trauma or post cardiopulmonary arrest had more tests and patients with stroke fewer. Convulsive status epilepticus and generalized slowing were found more frequently in the ICUs, and normal EEG, interictal epileptiform activity or focal non-epileptic slowing were more frequent in the non-ICU cases. In at least 12.4% of ICU patients, the test was expected to lead to an anti-epileptic management change. Cardiopulmonary arrest and age were predictive of any epileptic activity on the EEG in ICU patients. In conclusion, in our institution EmEEG is ordered by the ICUs in two thirds of the cases to exclude status epilepticus. Although status epilepticus is confirmed more frequently in the ICUs than on the Ward, the most frequent finding remains generalized slowing, which is found in half of the ICU-ordered EmEEGs. A conservative estimation is that EmEEG will lead to medication change in at least 1 out of 8 ICU patients. Cardioopulmonary arrest is predictive of epileptic activity and a prolonged EmEEG may also increase the yield.

Antiepileptic drug treatment of nonconvulsive seizures induced by experimental focal brain ischemia

Nonconvulsive seizures (NCSs) after traumatic and ischemic brain injury are often refractory to antiepileptic drug therapy and are associated with a decline in patient outcome. We recently characterized an in vivo rat model of focal brain ischemia-induced NCS and here sought to evaluate potential pharmacological treatments. Electroencephalographic activity was recorded continuously for 24 h in freely behaving rats subjected to permanent middle cerebral artery occlusion (MCAo). Rats were treated with an antiepileptic drug from one of seven different drug classes at ED(50) and 2x ED(50) doses (as reported in other rat seizure models), delivered as a single i.v. injection 20 min post-MCAo. Vehicle-treated rats (n = 9) had an 89% incidence of NCS with an average number of NCS of 8.6 +/- 1.9. The latency to onset of NCS was 32.5 +/- 3.4 min post-MCAo with an average duration of 49.1 +/- 8.2 s/event. The high doses of ethosuximide, gabapentin, fos-phenytoin, and valproate significantly reduced the incidence of NCS (11, 14, 14, and 38%, respectively), whereas midazolam, phenobarbital, and dextromethorphan had no significant effect at either dose. Across treatment groups, there was a low but significant correlation between the number of NCS events per animal and volume of brain infarction (r = 0.352). Antiepileptic drug therapy that prevented the occurrence of NCS also reduced mortality from 26 to 7%. Based on combined effects on NCS, infarction, neurological recovery, and mortality, ethosuximide and gabapentin were identified as having the best therapeutic profile.

The Management of Status Epilepticus

Status epilepticus is a major medical emergency associated with significant morbidity and mortality. Status epilepticus is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. Lorazepam in a dose of 0.1 mg/kg is the drug of first choice for terminating status epilepticus. Patients who continue to have clinical or EEG evidence of seizure activity after treatment with lorazepam should be considered to have refractory status epileptics and should be treated with a continuous infusion of propofol or midazolam. This article reviews current information regarding the management of status epilepticus in adults.

The treatment of status epilepticus

Status epilepticus (SE) is a life-threatening emergency that requires prompt treatment, including basic neuroresuscitation principles (the ABCs), antiepileptic drugs to stop the seizure, and identification of etiology. Symptomatic SE is more common in younger children. Treating the precipitating cause may prevent ongoing neurologic injury and facilitates seizure control. A systematic treatment regimen, planned in advance, is needed, including one for refractory status epilepticus (RSE). Here we emphasize definitions, clinical and electroencephalography stages, early treatment, special circumstances that may require immediate seizure control, and treatment of RSE. Because much clinical research in SE has been done in adults, we indicate the patient population studied.

Clinical policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with seizures

This clinical policy focuses on critical issues in the evaluation and management of adult patients with seizures. The medical literature was reviewed for articles that pertained to the critical questions posed. Subcommittee members and expert peer reviewers also supplied articles with direct bearing on this policy. This clinical policy focuses on 6 critical questions: What laboratory tests are indicated in the otherwise healthy adult patient with a new-onset seizure who has returned to a baseline normal neurologic status?Which new-onset seizure patients who have returned to a normal baseline require a head computed tomography (CT) scan in the emergency department (ED)?Which new-onset seizure patients who have returned to normal baseline need to be admitted to the hospital and/or started on an antiepileptic drug?What are effective phenytoin or fosphenytoin dosing strategies for preventing seizure recurrence in patients who present to the ED after having had a seizure with a subtherapeutic serum phenytoin level?What agent(s) should be administered to a patient in status epilepticus who continues to seize after having received benzodiazepine and phenytoin?When should electroencephalographic (EEG) testing be performed in the ED? Recommendations for patient management are provided for each 1 of these topics on the basis of strength of evidence (Level A, B, or C). Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies based on preliminary, inconclusive, or conflicting evidence, or based on consensus of the members of the Clinical Policies Committee. This clinical policy is intended for physicians working in hospital-based EDs.

Poststroke Epilepsy

Seizures and status epilepticus can be a presenting feature of acute stroke. They may occur in its early (<7 days) clinical course or be a remote (>7 days) complication. Most seizures are single, either partial or generalised. Early and remote seizures seem to have different predictors and pathogenesis. Seizures are more frequent in severe and disabling strokes, haemorrhagic strokes and those with cortical involvement. The risk of epilepsy is higher for patients with early seizures, cortical infarctions and lobar haemorrhages and in dependent patients. Early or remote seizures do not have a significant influence on dependency or mortality, although seizures and status epilepticus can be a direct cause of death. Treatment can be started after a first or a recurrent seizure. Treatment options include phenytoin, carbamazepine, valproic acid (valproate sodium) and the new antiepileptic drugs (AEDs). New AEDs can be used to decrease the likelihood of drug interactions and adverse effects in patients who do not tolerate the classic AEDs and in treatment failures with classic AEDs. Large observational studies to define prognostic factors for poststroke seizures in specific stroke subtypes are needed. Randomised controlled trials of AED prophylaxis for acute and remote seizures are essential to improve the evidence level of current guidelines and recommendations.

Emergent EEG: indications and diagnostic yield

The authors reviewed the reports of all emergent EEG (EmEEG) performed in our hospital within 1 hour of the test being ordered over a period of 52 months. Two hundred sixty-one EmEEG (12.8% of all EEG) were performed. The most common reason to order the test was a change in mental status or coma (17.6%). Although EmEEG was ordered to rule out status epilepticus (SE) in 60.2% of cases, this diagnosis was made in only 10.7% of patients. The only independent predictor for SE was a history of cardiac or respiratory arrest (odds [95% CI], 6.8 [2.7 to 16.9]).

Analysis of clinical characteristics and risk factors for mortality in human status epilepticus

PURPOSE

To analyse clinical data including aetiology, age, antecedents, classification and mortality in human status epilepticus (SE), and to assess prognostic factors for mortality.

METHODS

A prospective study was performed, including detailed analysis of clinical and laboratorial data of SE in individuals of any age, except neonates.

RESULTS

One hundred and eleven SE were included, with patients' age ranging from 3 months to 98 years. SE incidence peaked in the first year of life, and 59.4% of the individuals had previous epilepsy while 40.6% had not. The main underlying causes were noncompliance to treatment in the first group, and CNS infection, stroke and metabolic disturbances in the second group. Overall mortality was 19.8%, and deaths were correlated to aetiology and patient's age. Refractory SE affected 11.7% of the cases. Clinical types included focal, secondarily generalised and generalised SE. Clinical and clinicoelectrographic classifications were convergent, but EEG was essential for the diagnosis in 4.5% of the cases.

CONCLUSIONS

Epileptic patients are at greater risk to develop SE, however, individuals with no prior history of epilepsy and acute neurological problems can also present SE. Aetiology varies with patient's age, and mortality is high and related to age and underlying causes. Clinical and clinicoelectrographic classifications are usually convergent, but in some cases the diagnosis of SE would not be established without the EEG.

Treatment of status epilepticus: a survey of neurologists

BACKGROUND

New antiepileptic drugs (AEDs) have provided alternatives to traditional treatment paradigms for status epilepticus (SE).

METHODS

To determine current treatment preferences for generalized convulsive status epilepticus (GCSE), we surveyed 106 members of the Critical Care or Epilepsy sections of the American Academy of Neurology.

RESULTS

Most respondents initially treat patients with intravenous (IV) lorazepam (76%), followed by phenytoin or fosphenytoin (95%) if first-line therapy fails. Preferences for GCSE refractory to two AEDs (RSE) varied: 43% would give phenobarbital, 19% would give one of three continuous-infusion (cIV) AEDs (pentobarbital, midazolam, propofol), and 16% would give IV valproic acid. About half indicated "burst suppression" (56%) and half indicated "elimination of seizures" (41%) as the titration goal for cIV-AED therapy. About half (42%) would add a new cIV-AED, and the other half (41%) would not add another agent to treat electrographic SE refractory to four AEDs.

DISCUSSION

In accordance with published trials and general guidelines, neurologists most often use lorazepam followed by phenytoin or fosphenytoin as first-line and second-line therapies for GCSE. There is no consensus for third-line or fourth-line treatment for RSE. The treatment of RSE needs to be studied in a large, prospective, randomized, multicenter trial.

Clinical neurophysiology of epilepsy

Electroencephalography (EEG) continues to be the most important diagnostic tool in the management of patients with epilepsy. In particular, the high specificity of interictal epileptiform discharges makes scalp EEG a valuable tool in the evaluation of patients with a history of seizures or seizure-like episodes. Advances in technology, most notably the development of digital video-EEG, have significantly expanded the utility of EEG. In addition to the routine EEG, long-term monitoring studies including video-EEG, ambulatory EEG, and continuous EEG monitoring play important roles in various aspects of the diagnosis and treatment of epilepsy. Recent developments in computerized seizure detection and prediction algorithms, particularly those utilizing intracranial EEG electrodes, hold promise for future development of novel treatment strategies.

New management strategies in the treatment of status epilepticus

Status epilepticus is a neurologic emergency associated with high mortality and long-term disability. Recent advances in our understanding of the pathophysiological mechanisms involved in the initiation and perpetuation of seizure activity have revealed that status epilepticus is a dynamic and evolving process. Alterations at the cellular level parallel physiological, physical, and electrical changes at the bedside. Loss of cerebral autoregulation and neuronal damage begin after 30 minutes of continuous seizure activity. This understanding has led to changes in treatments of status epilepticus, which must be multidisciplinary and occur simultaneously in many different areas. The goals of pharmacological therapy are to terminate seizures early and prevent recurrence. Two recent large clinical studies have shown the benefit of early administration of benzodiazepines to control status epilepticus. Pharmacological algorithms designed to focus medical management have trended toward earlier and more aggressive treatment. The hope is that continued exploration into the basic mechanisms involved in status epilepticus and future controlled clinical trials defining optimal medical management will produce further advances.

Status epilepticus: a review of different syndromes, their current evaluation, and treatment

BACKGROUND

Status epilepticus (SE) encompasses a wide range of seizure types with different clinical presentations, pathophysiologies, treatment imperatives, and outcomes. The most dramatic and life-threatening form, generalized convulsive status epilepticus, has been reviewed in all of these aspects, but other less common types of SE have been described less extensively.

REVIEW SUMMARY

Definitions of generalized convulsive SE and its pathophysiology are reviewed briefly. Defining SE by a specific duration of seizures is controversial and has implications for studies and for clinical management. Several types of SE are different in their causes, presentations, and outcomes. Many are underdiagnosed. This article focuses on the pharmacology and clinical studies of several anticonvulsant medications used to treat SE. A protocol approach is not detailed. Rather, the clinical evaluation begins with meticulous diagnosis of the type of SE. Establishing the SE syndrome diagnosis and use of anticonvulsants with demonstrated effectiveness facilitate an appropriate treatment plan for individual patients. Recent developments in the basic science of SE raise the possibility of better treatments in the future.

CONCLUSIONS

As there are many types of seizures, there are also many types of SE. Each has unique presentations and treatment considerations. Review of actual clinical data from SE treatment studies should be helpful in devising the best treatment for an individual patient.

Non-convulsive status epilepticus: usefulness of clinical features in selecting patients for urgent EEG

BACKGROUND

Non-convulsive status epilepticus (NCSE) is status epilepticus without obvious tonic-clonic activity. Patients with NCSE have altered mental state. An EEG is needed to confirm the diagnosis, but obtaining an EEG on every patient with altered mental state is not practical.

OBJECTIVE

To determine whether clinical features could be used to predict which patients were more likely to be in NCSE and thus in need of an urgent EEG.

METHODS

Over a six month period, all patients for whom an urgent EEG was ordered to identify NCSE were enrolled. Neurology residents examined the patients and filled out a questionnaire without knowledge of the EEG results. The patients were divided into two groups, NCSE and non-NCSE, depending on the EEG result. The clinical features were compared between the two groups. The sensitivity and specificity of the features were calculated.

RESULTS

48 patients were enrolled, 12 in NCSE and 36 not in NCSE. Remote risk factors for seizures, severely impaired mental state, and ocular movement abnormalities were seen significantly more often in the NCSE group. The combined sensitivity of remote risk factors for seizures and ocular movement abnormalities was 100%.

CONCLUSIONS

There are certain clinical features that are more likely to be present in patients in NCSE compared with other types of encephalopathy. Either remote risk factors for seizures or ocular movement abnormalities were seen in all patients in NCSE. These features may be used to select which patients should have an urgent EEG.

Clinical and radiologic correlates of frontal intermittent rhythmic delta activity

To assess the clinical and radiologic correlates of frontal intermittent rhythmic delta activity (FIRDA), the authors reviewed the hospital charts of patients whose EEGs depicted this EEG finding, and recorded their past medical and neurologic history, the reason for hospital admission, and their neurologic status both on admission and during EEG recordings. Laboratory results on admission and concomitant to the EEG recording, computed tomography, or MRI findings during hospital admission were also reviewed. Sixty-eight patients were assessed. The gender ratio was 1:1; mean age was 56 years. Chronic disease occurred in 78% of patients, including hypertension (34%), diabetes (32%), and renal failure (18%). On admission, renal failure (n = 34) and hyperglycemia (n = 22) were most prominent. The majority of patients had at least one abnormal laboratory result. Thirty-eight of 51 patients in whom the level of consciousness was stated during EEG were described as awake. More than half of 58 patients whose EEG background activity was stipulated demonstrated diffuse slowing, mostly in the theta range. MRI was abnormal in 15 of 17 patients. Intrahemispheric lesions, particularly ischemic and hemorrhagic, were most common (n = 10), followed by basal ganglia lacunae (n = 4). Computed tomography was abnormal in 29 of 44 patients. Hemispheric pathology, diffuse or localized, occurred in 22 patients. Frontal intermittent rhythmic delta activity is associated with mild to moderate encephalopathy and is detected principally in awake patients. Most patients in this series had chronic systemic illness. Old ischemic structural brain lesions may predispose some patients to develop FIRDA during acute metabolic derangement, such as uremia and hyperglycemia. Frontal intermittent rhythmic delta activity was not associated with EEG epileptiform activity. Deep midline lesions, posterior fossa tumors, and hydrocephalus were not detected in this series of patients with FIRDA.

Adult patient perceptions of emergency rectal medications for refractory seizures

Background. Rectally administered benzodiazepine antiepilepsy drugs (AEDs) are a safe and effective therapy for acute repetitive seizures in patients on stable maintenance AEDs. Such medication provides an earlier treatment option for seizure control prior to emergency department (ED) visitation and may be administered outside of the hospital in carefully selected patients. The use of rectal medications, however, has a perceived association with fear and embarrassment. This study sought to address patient attitudes toward rectally delivered AEDs. Methods. A written, eight-question survey regarding adult patient attitudes toward rectal medication and ED visits was prospectively administered to 91 consecutive epilepsy patients in an epilepsy-based practice setting. Primary caretakers responded when patients were unable to do so. RESULTS: Forty-eight female and thirty-two male survey responses were analyzed. The mean patient population was age 42.7 years with epilepsy for 23.7 years on 1.7 AEDs with a seizure frequency of 6.6/month. The majority had partial and generalized tonic-clonic seizures and had obtained at least a high school education. Three patients (6%) had symptomatic generalized epilepsy and required caretaker responses. Eleven of ninety-one (12.1%) surveys were incomplete for analysis. Seventy-six of eighty (95%) respondents completed at least 50% of the survey questions. Forty-three of sixty-four (67.2%) respondents were not embarrassed by rectal AEDs, and did not fear being teased by others. Additionally, most felt rectal AEDs were a good option in epilepsy management, yet would prefer a private setting for administration. Both seizures and rectal AED use appeared to be equally embarrassing to patients. While 53 of 76 (69.7%) reported ED visitation for seizures at some time, the vast majority (56/60, 93.3%) reported they would prefer treatment outside the hospital, as opposed to ED transport. Conclusions. The results from this adult patient survey suggest that individuals with epilepsy do not object to earlier administration of emergency rectal seizure medication relative to ED visitation. An undesirable perception of rectal medications in seizure emergencies does not appear to be limited by patient acceptance.

Continuous electroencephalographic monitoring in neurocritical care

This article reviews current and future applications of continuous electroencephalography (cEEG) to monitor brain function and physiology in the neurologic intensive care unit. In comatose patients, cEEG may provide otherwise unobtainable information and influence therapeutic management, and also help determine the prognosis of patients with acute brain injury. This technique is best used for the detection of subclinical seizures, which may frequently occur during or after treatment of convulsive status epilepticus and after many types of acute brain injury, particularly trauma. The other main application of cEEG is as a primary monitor of brain function. cEEG can detect focal cerebral ischemia, such as that caused by vasospasm after subarachnoid hemorrhage, as well as global ischemia related to intracranial pressure elevation and insufficient cerebral perfusion pressure. Other potential applications include prognostication in coma and titration of continuous infusion sedative therapy. New technologic developments include continuous digital video EEG, automated seizure-detection software, and user-friendly online quantitative EEG analysis.

Nonconvulsive status epilepticus after subarachnoid hemorrhage

OBJECTIVE

Although in-hospital seizures have been reported for 3 to 24% of patients with aneurysmal subarachnoid hemorrhage (SAH), nonconvulsive status epilepticus (NCSE) has not been previously described. We sought to determine the frequency and clinical features of NCSE among comatose patients with SAH.

METHODS

Between November 1997 and February 2000, we performed continuous electroencephalographic (cEEG) monitoring for at least 24 hours for all patients with aneurysmal SAH who were treated in our neurological intensive care unit and exhibited unexplained coma or neurological deterioration. NCSE was diagnosed when cEEG monitoring demonstrated continuous or repetitive electrographic seizures exceeding 1 hour in duration. Refractory NCSE was treated aggressively with intravenous anticonvulsant administration and continuous-infusion midazolam therapy.

RESULTS

Of 233 patients with SAH who survived the first 48 hours of hospitalization, 101 were stuporous or comatose at some point during their hospitalization. Twenty-six of those patients underwent cEEG monitoring, and eight were diagnosed as having NCSE, an average of 18 days (range, 5-38 d) after SAH. All eight patients were receiving prophylactic anticonvulsant therapy. Four patients were persistently comatose and four demonstrated deterioration to stupor or coma; only one exhibited overt tonicoclonic activity. A worst Hunt and Hess grade of IV or V, older age, ventricular drainage, and cerebral edema on computed tomographic scans were identified as risk factors for NCSE (all P < 0.01). NCSE was successfully terminated for five patients (63%), but only one experienced clinical improvement, which was transient; all eight patients eventually died after a period of prolonged coma.

CONCLUSION

cEEG monitoring detected NCSE for 8% of patients with SAH and otherwise unexplained coma or neurological deterioration. The seizures were highly refractory to therapy, and the prognosis for these patients was extremely poor. Routine postoperative cEEG monitoring of patients with SAH who are at high risk for NCSE, allowing earlier diagnosis and treatment, offers the best chance of improving the outcomes for patients with this disorder.

Nonconvulsive status epilepticus with frontal features: quantitating severity of subclinical epileptiform discharges provides a marker for treatment efficacy, recurrence and outcome

Nonconvulsive status epilepticus (NCSE) is difficult to diagnose but is an important cause of cognitive impairment. Electroencephalogram (EEG) monitoring is required for diagnosis and treatment. Little is known regarding the stability of subclinical epileptiform discharges (SEDs) preceding NCSE nor what strategies may optimize patient outcomes. We report extended follow-up of patients with recurrent frontal SEDs, integrating EEG and cognitive findings before and following treatment of NCSE, and show that quantitating SED severity provides an objective marker of treatment efficacy and recurrence.

Progress in clinical neurosciences: Status epilepticus: a critical review of management options

Although generalized tonic-clonic status epilepticus (SE) is frequently seen, an evidence-based approach to management is limited by a lack of randomized clinical studies. Clinical practice, therefore, relies on a combination of expert recommendations, local hospital guidelines and dogma based on individual preference and past successes. This review explores selected and controversial aspects of SE in adults and provides a critical appraisal of currently recommended management strategies.

Is it status?

Nonconvulsive status epilepticus (NCSE) is difficult to diagnose in the obtunded/comatose patient. Such patients often have other serious medical conditions, and the diagnosis is frequently delayed. We review criteria for diagnosis, treatment, and prognosis of NCSE in this setting. Terms that have been used to describe SE in obtunded/comatose patients without tonic-clonic convulsions include subtle generalized SE, electrographic SE, SE in comatose patients, generalized electrographic SE, non-tonic-clonic SE, subclinical SE, and NCSE. Sometimes the same term has been used when describing different disorders, and different terms are often applied for the same entity. The incidence of NCSE in obtunded/comatose patients is uncertain. Clinically they may display subtle, intermittent focal or multifocal rhythmic movements suggestive of seizures; there may not be movements. NCSE can occur in a variety of disorders, including hypoxia, metabolic disturbances, and after convulsive seizures. A number of EEG patterns have been described in NCSE, and many of these are controversial, particularly as to whether they are ictal. These include periodic lateralized epileptiform discharges (PLEDS), bilateral independent PLEDS (BIPLEDS), periodic epileptiform discharges (PEDS), which can be either focal or generalized, and generalized triphasic waves (TWs). The diagnostic criteria for NCSE also are controversial, and there are no agreed-on criteria to diagnose NCSE in obtunded/comatose patients, nor is there consensus on how it should it be treated. Furthermore, outcome is poor, and several studies suggest that treatment may not be helpful.

Continuous EEG monitoring in the intensive care unit

Continuous EEG (CEEG) monitoring allows uninterrupted assessment of cerebral cortical activity with good spatial resolution and excellent temporal resolution. Thus, this procedure provides a means of constantly assessing brain function in critically ill obtunded and comatose patients. Recent advances in digital EEG acquisition, storage, quantitative analysis, and transmission have made CEEG monitoring in the intensive care unit (ICU) technically feasible and useful. This article summarizes the indications and methodology of CEEG monitoring in the ICU, and discusses the role of some quantitative EEG analysis techniques in near real-time remote observation of CEEG recordings. Clinical examples of CEEG use, including monitoring of status epilepticus, assessment of ongoing therapy for treatment of seizures in critically ill patients, and monitoring for cerebral ischemia, are presented. Areas requiring further development of CEEG monitoring techniques and indications are discussed.