Acute seizures after intracerebral hemorrhage: a factor in progressive midline shift and outcome

Neonatal seizures triple the risk of a remote seizure after perinatal ischemic stroke

OBJECTIVES

To determine incidence rates and risk factors of remote seizure after perinatal arterial ischemic stroke.

METHODS

We retrospectively identified a population-based cohort of children with perinatal arterial ischemic stroke (presenting acutely or in a delayed fashion) from a large Northern Californian integrated health care system. We determined incidence and predictors of a remote seizure (unprovoked seizure after neonatal period, defined as 28 days of life) by survival analyses, and measured epilepsy severity in those with active epilepsy (≥1 remote seizure and maintenance anticonvulsant treatment) at last follow-up.

RESULTS

Among 87 children with perinatal stroke, 40 (46%) had a seizure in the neonatal period. During a median follow-up of 7.1 years (interquartile range 3.2-10.5), 37 children had ≥1 remote seizure. Remote seizure risk was highest during the first year of life, with a 20% (95% confidence interval [CI] 13%-30%) cumulative incidence by 1 year of age, 46% (CI 35%-58%) by 5 years, and 54% (CI 41%-67%) by 10 years. Neonatal seizures increased the risk of a remote seizure (hazard ratio 2.8, CI 1.3-5.8). Children with neonatal seizures had a 69% (CI 48%-87%) cumulative incidence of remote seizure by age 10 years. Among the 24 children with active epilepsy at last follow-up, 8 (33%) were having monthly seizures despite an anticonvulsant and 7 (29%) were on more than one anticonvulsant.

CONCLUSIONS

Remote seizures and epilepsy, including medically refractory epilepsy, are common after perinatal stroke. Neonatal seizures are associated with nearly 3-fold increased remote seizure risk.

Should We Treat Electroencephalographic Discharges in the Clinic or in the Intensive Care Unit, and if so When and How?

The important question that often emerges in the clinic is how aggressive the therapy for nonconvulsive status epilepticus and electrical status epilepticus in sleep ought to be and how continuous the discharges in each of these 2 entities should be before therapy is aimed at them. Additionally, as the use of electroencephalographic monitoring continues to expand to include the clinic and intensive care unit populations, it is important to identify epileptiform patterns that warrant identification and treatment. This review will present the state-of-the-art data and suggest algorithms to manage these conditions.

Baseline EEG pattern on continuous ICU EEG monitoring and incidence of seizures

PURPOSE

To identify the probability of detecting nonconvulsive seizures based on the initial pattern seen in the first 30 minutes of continuous EEG (cEEG) monitoring.

METHODS

Continuous EEG monitoring reports from 243 adult patients were reviewed, assessing the baseline cEEG monitoring pattern and the presence of seizures during the entire monitoring period. The baseline EEG patterns were classified into nine categories: seizures, lateralized periodic discharges, generalized periodic discharges, focal epileptiform discharges, burst suppression, asymmetric background, generalized slowing, generalized periodic discharges with triphasic morphology, and normal.

RESULTS

Overall, 51 patients (21%) had nonconvulsive seizures at any time during cEEG monitoring. Notably, 112 patients had generalized slowing as the initial EEG pattern, and none of these patients were noted to have seizures. Seizure rates among the types of baseline EEG findings were as follows: lateralized periodic discharges (56%, n = 9), burst suppression (50%, n = 10), generalized periodic discharges (50%, n = 2), normal (33%, n = 3), focal epileptiform discharges (31%, n = 35), and asymmetric background (11%, n = 46).

CONCLUSIONS

Patients with only generalized slowing seen on the baseline EEG recording are unlikely to develop seizures on subsequent cEEG monitoring. Depending on the clinical circumstance, the standard duration of cEEG recording (24-48 hours) may be unnecessary in patients with generalized slowing as their only cEEG abnormality.

Consensus statement on continuous EEG in critically ill adults and children, part I: indications

INTRODUCTION

Critical Care Continuous EEG (CCEEG) is a common procedure to monitor brain function in patients with altered mental status in intensive care units. There is significant variability in patient populations undergoing CCEEG and in technical specifications for CCEEG performance.

METHODS

The Critical Care Continuous EEG Task Force of the American Clinical Neurophysiology Society developed expert consensus recommendations on the use of CCEEG in critically ill adults and children.

RECOMMENDATIONS

The consensus panel recommends CCEEG for diagnosis of nonconvulsive seizures, nonconvulsive status epilepticus, and other paroxysmal events, and for assessment of the efficacy of therapy for seizures and status epilepticus. The consensus panel suggests CCEEG for identification of ischemia in patients at high risk for cerebral ischemia; for assessment of level of consciousness in patients receiving intravenous sedation or pharmacologically induced coma; and for prognostication in patients after cardiac arrest. For each indication, the consensus panel describes the patient populations for which CCEEG is indicated, evidence supporting use of CCEEG, utility of video and quantitative EEG trends, suggested timing and duration of CCEEG, and suggested frequency of review and interpretation.

CONCLUSION

CCEEG has an important role in detection of secondary injuries such as seizures and ischemia in critically ill adults and children with altered mental status.

EEG and Coma

Coma is defined as a state of extreme unresponsiveness, in which a person exhibits no voluntary movement or behavior even to painful stimuli. The utilization of EEG for patients in coma has increased dramatically over the last few years. In fact, many institutions have set protocols for continuous EEG (cEEG) monitoring for patients in coma due to potential causes such as subarachnoid hemorrhage or cardiac arrest. Consequently, EEG plays an important role in diagnosis, managenent, and in some cases even prognosis of coma patients.

Pathophysiology and Management of Moderate and Severe Traumatic Brain Injury in Children

Traumatic brain injury remains a leading cause of morbidity and mortality in children. Key pathophysiologic processes of traumatic brain injury are initiated by mechanical forces at the time of trauma, followed by complex excitotoxic cascades associated with compromised cerebral autoregulation and progressive edema. Acute care focuses on avoiding secondary insults, including hypoxia, hypotension, and hyperthermia. Children with moderate or severe traumatic brain injury often require intensive monitoring and treatment of multiple parameters, including intracranial pressure, blood pressure, metabolism, and seizures, to minimize secondary brain injury. Child neurologists can play an important role in acute and long-term care. Acutely, as members of a multidisciplinary team in the intensive care unit, child neurologists monitor for early signs of neurological change, guide neuroprotective therapies, and transition patients to long-term recovery. In the longer term, neurologists are uniquely positioned to treat complications of moderate and severe traumatic brain injury, including epilepsy and cognitive and behavioral issues.

Animal Models of Posttraumatic Seizures and Epilepsy

Posttraumatic epilepsy (PTE) is one of the most common and devastating complications of traumatic brain injury (TBI). Currently, the etiopathology and mechanisms of PTE are poorly understood and as a result, there is no effective treatment or means to prevent it. Antiepileptic drugs remain common preventive strategies in the management of TBI to control acute posttraumatic seizures and to prevent the development of PTE, although their efficacy in the latter case is disputed. Different strategies of PTE prophylaxis have been showing promise in preclinical models, but their translation to the clinic still remains elusive due in part to the variability of these models and the fact they do not recapitulate all complex pathologies associated with human TBI. TBI is a multifaceted disorder reflected in several potentially epileptogenic alterations in the brain, including mechanical neuronal and vascular damage, parenchymal and subarachnoid hemorrhage, subsequent toxicity caused by iron-rich hemoglobin breakdown products, and energy disruption resulting in secondary injuries, including excitotoxicity, gliosis, and neuroinflammation, often coexisting to a different degree. Several in vivo models have been developed to reproduce the acute TBI cascade of events, to reflect its anatomical pathologies, and to replicate neurological deficits. Although acute and chronic recurrent posttraumatic seizures are well-recognized phenomena in these models, there is only a limited number of studies focused on PTE. The most used mechanical TBI models with documented electroencephalographic and behavioral seizures with remote epileptogenesis include fluid percussion, controlled cortical impact, and weight-drop. This chapter describes the most popular models of PTE-induced TBI models, focusing on the controlled cortical impact and the fluid percussion injury models, the methods of behavioral and electroencephalogram seizure assessments, and other approaches to detect epileptogenic properties, and discusses their potential application for translational research.

Seizure burden in subarachnoid hemorrhage associated with functional and cognitive outcome

OBJECTIVE

To assess the relationship between seizure burden on continuous EEG (cEEG) and functional as well as cognitive outcome 3 months after subarachnoid hemorrhage (SAH).

METHODS

The study included all consecutive patients with a spontaneous SAH admitted to the Columbia University Medical Center Neurological Intensive Care Unit and monitored with cEEG between 1996 and 2013. Seizure burden was defined as the duration, in hours, of seizures on cEEG. Cognitive outcomes were measured with the Telephone Interview for Cognitive Status (TICS, ranging from 0 to 51, indicating poor to good global mental status).

RESULTS

Overall, 402 patients with SAH were included with a median age of 58 years (interquartile range [IQR] 46-68 years). The median duration of cEEG monitoring was 96 hours (IQR 48-155 hours). Seizures were recorded in 50 patients (12%), in whom the median seizure burden was 6 hours (IQR 1-13 hours). At 3 months, in multivariate analysis, seizure burden was associated with unfavorable functional and cognitive outcome. Every hour of seizure on cEEG was associated with an odds ratio of 1.10 (95% confidence interval [CI] 1.01-1.21, p = 0.04) to 3-month disability and mortality, and the TICS-score decreased, on average, by 0.16 points (adjusted coefficient -0.19, 95% CI -0.33 to -0.05, p = 0.01).

CONCLUSION

In this study, after adjusting for established predictors, seizure burden was associated with functional outcome and cognitive impairment 3 months after SAH.

Rhythmic and periodic EEG patterns of 'ictal-interictal uncertainty' in critically ill neurological patients

OBJECTIVES

To study periodic and rhythmic EEG patterns classified according to Standardized Critical Care EEG Terminology (SCCET) of the American Clinical Neurophysiology Society and their relationship to electrographic seizures.

METHODS

We classified 655 routine EEGs in 371 consecutive critically ill neurological patients into (1) normal EEGs or EEGs with non-specific abnormalities or interictal epileptiform discharges, (2) EEGs containing unequivocal ictal EEG patterns, and (3) EEGs showing rhythmic and periodic EEG patterns of 'ictal-interictal uncertainty' (RPPIIIU) according to SCCET.

RESULTS

313 patients (84.4%) showed normal EEGs, non-specific or interictal abnormalities, 14 patients (3.8%) had EEGs with at least one electrographic seizure, and 44 patients (11.8%) at least one EEG containing RPPIIIU, but no EEG with electrographic seizures. Electrographic seizures occurred in 11 of 55 patients (20%) with RPPIIIU, but only in 3 of 316 patients (0.9%) without RPPIIIU (p⩽0.001). Conversely, we observed RPPIIIU in 11 of 14 patients (78.6%) with electrographic seizures, but only in 44 of 357 patients (12.3%) without electrographic seizures (p⩽0.001).

CONCLUSIONS

On routine-EEG in critically ill neurological patients RPPIIIU occur 3 times more frequently than electrographic seizures and are highly predictive for electrographic seizures.

SIGNIFICANCE

RPPIIIU can serve as an indication for continuous EEG recordings.

Electrophysiologic monitoring in acute brain injury

To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications.

The enigma of the latent period in the development of symptomatic acquired epilepsy - Traditional view versus new concepts

A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "latent period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable latent period. Even though the latent period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a latent period is spotty both for animal models and human epilepsy. Knowing whether a latent period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.

Modeling early-onset post-ischemic seizures in aging mice

Stroke is the leading cause of seizures and epilepsy in the aged population, with post-stroke seizures being a poor prognostic factor. The pathological processes underlying post-stroke seizures are not well understood and studies of these seizures in aging/aged animals remain scarce. Therefore, our primary objective was to model post-stroke seizures in aging mice (C57 black strain, 16-20 months-old), with a focus on early-onset, convulsive seizures that occur within 24-hours of brain ischemia. We utilized a middle cerebral artery occlusion model and examined seizure activity and brain injury using combined behavioral and electroencephalographic monitoring and histological assessments. Aging mice exhibited vigorous convulsive seizures within hours of the middle cerebral artery occlusion. These seizures manifested with jumping, rapid running, barrel-rolling and/or falling all in the absence of hippocampal-cortical electrographic discharges. Seizure development was closely associated with severe brain injury and acute mortality. Anticonvulsive treatments after seizure occurrence offered temporary seizure control but failed to improve animal survival. A separate cohort of adult mice (6-8 months-old) exhibited analogous early-onset convulsive seizures following the middle cerebral artery occlusion but had better survival outcomes following anticonvulsive treatment. Collectively, our data suggest that early-onset convulsive seizures are a result of severe brain ischemia in aging animals.

Steps to consider in the approach and management of critically ill patient with spontaneous intracerebral hemorrhage

Spontaneous intracerebral hemorrhage is a type of stroke associated with poor outcomes. Mortality is elevated, especially in the acute phase. From a pathophysiological point of view the bleeding must traverse different stages dominated by the possibility of re-bleeding, edema, intracranial hypertension, inflammation and neurotoxicity due to blood degradation products, mainly hemoglobin and thrombin. Neurological deterioration and death are common in early hours, so it is a true neurological-neurosurgical emergency. Time is brain so that action should be taken fast and accurately. The most significant prognostic factors are level of consciousness, location, volume and ventricular extension of the bleeding. Nihilism and early withdrawal of active therapy undoubtedly influence the final result. Although there are no proven therapeutic measures, treatment should be individualized and guided preferably by pathophysiology. The multidisciplinary teamwork is essential. Results of recently completed studies have birth to promising new strategies. For correct management it’s important to establish an orderly and systematic strategy based on clinical stabilization, evaluation and establishment of prognosis, avoiding secondary insults and adoption of specific individualized therapies, including hemostatic therapy and intensive control of elevated blood pressure. Uncertainty continues regarding the role of surgery.

Which EEG patterns in coma are nonconvulsive status epilepticus?

Nonconvulsive status epilepticus (NCSE) is common in patients with coma with a prevalence between 5% and 48%. Patients in deep coma may exhibit epileptiform EEG patterns, such as generalized periodic spikes, and there is an ongoing debate about the relationship of these patterns and NCSE. The purposes of this review are (i) to discuss the various EEG patterns found in coma, its fluctuations, and transitions and (ii) to propose modified criteria for NCSE in coma. Classical coma patterns such as diffuse polymorphic delta activity, spindle coma, alpha/theta coma, low output voltage, or burst suppression do not reflect NCSE. Any ictal patterns with a typical spatiotemporal evolution or epileptiform discharges faster than 2.5 Hz in a comatose patient reflect nonconvulsive seizures or NCSE and should be treated. Generalized periodic diacharges or lateralized periodic discharges (GPDs/LPDs) with a frequency of less than 2.5 Hz or rhythmic discharges (RDs) faster than 0.5 Hz are the borderland of NCSE in coma. In these cases, at least one of the additional criteria is needed to diagnose NCSE (a) subtle clinical ictal phenomena, (b) typical spatiotemporal evolution, or (c) response to antiepileptic drug treatment. There is currently no consensus about how long these patterns must be present to qualify for NCSE, and the distinction from nonconvulsive seizures in patients with critical illness or in comatose patients seems arbitrary. The Salzburg Consensus Criteria for NCSE [1] have been modified according to the Standardized Terminology of the American Clinical Neurophysiology Society [2] and validated in three different cohorts, with a sensitivity of 97.2%, a specificity of 95.9%, and a diagnostic accuracy of 96.3% in patients with clinical signs of NCSE. Their diagnostic utility in different cohorts with patients in deep coma has to be studied in the future. This article is part of a Special Issue entitled "Status Epilepticus".

Lacosamide in status epilepticus: Update on the TRENdS study

Many patients with critical illness have been noted to have nonconvulsive seizures (NCSs) and nonconvulsive status epilepticus (NCSE). How aggressively these seizures should be treated is unclear. Many investigators feel that the morbidity of NCSs and NCSE is different from that of generalized convulsive status epilepticus (GCSE), so treatment should be less urgent. Consequently, many nonsedating AEDs have been used to treat NCSs and NCSE in patients with critical illness. Randomized, controlled trials demonstrating the efficacy of AEDs in NCSs and NCSE are lacking. The Treatment of Recurrent Electrographic Nonconvulsive Seizures (TRENdS) study compared lacosamide to fosphenytoin in the treatment of NCSs. An update of the study is presented. This article is part of a Special Issue entitled "Status Epilepticus".

Changes in volume of giant intracranial aneurysms treated by surgical strategies other than direct clipping

BACKGROUND

Giant intracranial aneurysms (GIA) are often not eligible for direct clip occlusion. Surgical alternatives include partial clip occlusion or the placement of a cerebrovascular bypass or the combination of both. These alternative indirect strategies are expected to lead to a decrease in GIA volume over time rather than instantaneously. To examine whether this is the case, we analyzed follow-up imaging results 1 year after surgery.

METHODS

We retrospectively screened the prospective GIA Registry's imaging database for anterior circulation GIA treated by surgical strategies other than direct clipping. We measured pre- and 1-year post-treatment GIA volume, lateral ventricle volume (LVV), and mid-line shift (MLS) in 19 cases.

RESULTS

After a mean follow-up of 466 days (standard deviation ±171) GIA volumes decreased from 9.6 cm(3) (interquartile range (IQR) 6.1-14.1) to 4.3 cm(3) (IQR 2.9-5.7; p < 0.01). Ipsilateral LVV increased from 8.6 cm(3) (IQR 6.4-24.9) to 16.0 cm(3) (IQR 9.1-27.2; p < 0.01) while contralateral LVV increased from 10.3 cm(3) (IQR 7.3-20.1) to 11.7 cm(3) (IQR 8.2-19.4; p = 0.02). MLS changed from 0.1 mm (IQR -1.9 to 2.0) to -0.9 mm (IQR -1.8 to 0.4; p = 0.03). The decrease in GIA volume correlated with the increase in ipsilateral LVV (rs = 0.60; p = 0.01) but not with the changes in MLS (rs = 0.41; p = 0.08).

CONCLUSIONS

In our patient cohort, surgical strategies other that direct clipping for the treatment of anterior circulation GIA lead to a significant decrease in GIA volume over time. The resulting decrease in mass effect was more sensitively monitored by the measurement of changes in ipsilateral LVV than changes in MLS.

CLINICAL TRIAL REGISTRATION-URL

http://www.clinicaltrials.gov . Unique identifier: NCT02066493.

Dual Therapeutic Effects of C-10068, a Dextromethorphan Derivative, Against Post-Traumatic Nonconvulsive Seizures and Neuroinflammation in a Rat Model of Penetrating Ballistic-Like Brain Injury

Post-traumatic seizures can exacerbate injurious outcomes of severe brain trauma, yet effective treatments are limited owing to the complexity of the pathology underlying the concomitant occurrence of both events. In this study, we tested C-10068, a novel deuterium-containing analog of (+)-N-methyl-3-ethoxymorphinan, in a rat model of penetrating ballistic-like brain injury (PBBI) and evaluated the effects of C-10068 on PBBI-induced nonconvulsive seizures (NCS), acute neuroinflammation, and neurofunctional outcomes. NCS were detected by electroencephalographic monitoring. Neuroinflammation was evaluated by immunohistochemical markers, for example, glial fibrillary acidic protein and major histocompatibility complex class I, for activation of astrocytes and microglia, respectively. Neurofunction was tested using rotarod and Morris water maze tasks. Three infusion doses of C-10068 (1.0, 2.5, and 5.0 mg/kg/h × 72 h) were tested in the antiseizure study. Neuroinflammation and neurofunction were evaluated in animals treated with 5.0 mg/kg/h × 72 h C-10068. Compared to vehicle treatment, C-10068 dose dependently reduced PBBI-induced NCS incidence (40-50%), frequency (20-70%), and duration (30-82%). The most effective antiseizure dose of C-10068 (5.0 mg/kg/h × 72 h) also significantly attenuated hippocampal astrocyte activation and perilesional microglial reactivity post-PBBI. Within C-10068-treated animals, a positive correlation was observed in reduction in NCS frequency and reduction in hippocampal astrocyte activation. Further, C-10068 treatment significantly attenuated astrocyte activation in seizure-free animals. However, C-10068 failed to improve PBBI-induced motor and cognitive functions with the dosing regimen used in this study. Overall, the results indicating that C-10068 exerts both potent antiseizure and antiinflammatory effects are promising and warrant further investigation.

Acute brain failure in severe sepsis: a prospective study in the medical intensive care unit utilizing continuous EEG monitoring

PURPOSE

Investigate the prevalence, risk factors and impact of continuous EEG (cEEG) abnormalities on mortality through the 1-year follow-up period in patients with severe sepsis.

METHODS

Prospective, single-center, observational study of consecutive patients admitted with severe sepsis to the Medical ICU at an academic medical center.

RESULTS

A total of 98 patients with 100 episodes of severe sepsis were included; 49 patients (50%) were female, median age was 60 (IQR 52-74), the median non-neuro APACHE II score was 23.5 (IQR 18-28) and median non-neuro SOFA score was 8 (IQR 6-11). Twenty-five episodes had periodic discharges (PD), of which 11 had nonconvulsive seizures (NCS). No patient had NCS without PD. Prior neurological history was associated with a higher risk of PD or NCS (45 vs. 17%; CI 1.53-10.43), while the non-neuro APACHE II, non-neuro SOFA, severity of cardiovascular shock and presence of sedation during cEEG were associated with a lower risk of PD or NCS. Clinical seizures before cEEG were associated with a higher risk of nonconvulsive status epilepticus (24 vs. 6%; CI 1.42-19.94) while the non-neuro APACHE II and non-neuro SOFA scores were associated with a lower risk. Lack of EEG reactivity was present in 28% of episodes. In the survival analysis, a lack of EEG reactivity was associated with higher 1-year mortality [mean survival time 3.3 (95% CI 1.8-4.9) vs. 7.5 (6.4-8.7) months; p = 0.002] but the presence of PD or NCS was not [mean survival time 3.3 (95% CI 1.8-4.9) vs. 7.5 (6.4-8.7) months; p = 0.592]. Lack of reactivity was more frequent in patients on continuous sedation during cEEG. In patients with available 1-year data (34% of the episodes), 82% had good functional outcome (mRS ≤ 3, n = 27). There were no significant predictors of functional outcome, late cognition, and no patient with complete follow-up data developed late seizure or new epilepsy.

CONCLUSIONS

NCS and PD are common in patients with severe sepsis and altered mental status. They were less frequent among the most severely sick patients and were not associated with outcome in this study. Lack of EEG reactivity was more frequent in patients on continuous sedation and was associated with mortality up to 1 year after discharge. Larger studies are needed to confirm these findings in a broader population and to further evaluate long-term cognitive outcome, risk of late seizure and epilepsy.

Nonconvulsive seizures and status epilepticus in pediatric head trauma: A national survey

OBJECTIVES

It remains uncertain whether nonconvulsive seizures and nonconvulsive status epilepticus in pediatric traumatic brain injury are deleterious to the brain and/or impact the recovery from injury. Consequently, optimal electroencephalographic surveillance and management is unknown. We aimed to determine specialists' opinion regarding the detection and treatment of nonconvulsive seizures or nonconvulsive status epilepticus in pediatric traumatic brain injury, regardless of their practice.

METHODS

In 2012, 183 surveys were sent to all 93 neurologists, 27 neurosurgeons, and 63 intensivists in the14 tertiary pediatric hospitals across Canada. The survey included an initial scenario of pediatric TBI that evolved into three further scenarios. Each scenario had required responses and an embedded branching logic algorithm ascertaining clinical management. The survey instrument assimilated data about the importance of nonconvulsive status epilepticus and nonconvulsive seizures detection and treatment, and whether they are a cause of brain injury that adversely affects neurologic outcomes.

RESULTS

Of the 79 specialists who replied (43% response rate), 68%-78% elected to order an electroencephalographic across all four scenarios, and one-third (31%-36%; scenario dependent) would request an urgent electroencephalographic (within the hour) in the comatose pediatric traumatic brain injury patient. In the absence of pharmacologic paralysis or intracranial pressure spikes, half-hour electroencephalographic (41%-55%) was preferred over ⩾24-h continuous electroencephalographic monitoring (29%-40%). Finally, nonconvulsive status epilepticus (81%-87%) and nonconvulsive seizures (61%-73%) were considered to be a cause of poor neurologic outcomes warranting aggressive pharmacologic management.

CONCLUSION

The Canadian specialists' opinion is that nonconvulsive seizures and nonconvulsive status epilepticus are biomarkers of brain injury and contribute to worsened outcomes. This suggests the urgency of future outcome-oriented research in the identification and management of nonconvulsive seizures or nonconvulsive status epilepticus.

Continuous EEG monitoring in adults in the intensive care unit (ICU)

Continuous EEG monitoring in the ICU is different from planned EEG due to the rather urgent nature of the indications, explaining the fact that recording is started in certain cases by the clinical team in charge of the patient's care. Close collaboration between neurophysiology teams and intensive care teams is essential. Continuous EEG monitoring can be facilitated by quantified analysis systems. This kind of analysis is based on certain signal characteristics, such as amplitude or frequency content, but raw EEG data should always be interpreted if possible, since artefacts can sometimes impair quantified EEG analysis. It is preferable to work within a tele-EEG network, so that the neurophysiologist has the possibility to give an interpretation on call. Continuous EEG monitoring is thus useful in the diagnosis of non-convulsive epileptic seizures or purely electrical discharges and in the monitoring of status epilepticus when consciousness disorders persist after initial treatment. A number of other indications are currently under evaluation.

Association between seizures and outcomes among intracerebral hemorrhage patients: the China National Stroke Registry

BACKGROUND

To determine whether the presence of seizures in patients with spontaneous intracerebral hemorrhage (ICH) was associated with in-hospital complications and measured outcomes.

METHODS

This prospective cohort study from the China National Stroke Registry included consecutive patients with ICH between August 2007 and September 2008. In-hospital complications, functional outcomes, and mortality at 3, 6, and 12 months were compared between patients with seizures and those without seizures occurring at ICH onset and during hospitalization. Poor functional outcome was defined as a modified Rankin Scale score between 3 and 6. Poor functional outcome and mortality were stratified by stroke severity using Glasgow Coma Scale scores on admission.

RESULTS

The study included 3216 patients with ICH and 139 of them (4.3%) experienced seizures. The presence of seizures was associated with high in-hospital complications including atrial fibrillation (P = .004), pneumonia (P = .001), as well as lower rehabilitation assessment rates (P = .033) compared with patients without seizures. ICH patients with seizures had poorer functional outcome at 3-month (P = .012), 6-month (P = .007), and 12-month (P = .001) follow-up. They also had higher mortality at 3 months (P = .045), 6 months (P = .005), and 12 months (P = .002). Patients with mild strokes had poorer functional outcome and higher mortality (P < .005) if seizures occurred.

CONCLUSIONS

The presence of seizures in patients with ICH was associated with high in-hospital complications and indicates poor outcomes at 3-, 6-, and 12-month follow-up. Quality improvement strategies targeting ICH patients with seizures especially mild stroke may help improve prognoses.

Intracranial haemorrhage: therapeutic interventions and anaesthetic management

Intracranial haemorrhage (ICH) is a devastating cause of stroke. Although the total incidence of ICH has remained stable worldwide, the proportion associated with the use of anticoagulant medications is increasing. Innovative interventions developed to improve patient outcomes often require peri-procedure anaesthetic management. This non-systematic review examines the pathophysiology of ICH at a clinical level, reports on novel therapeutic interventions, many of which are currently in clinical trials, and reviews the current published recommendations for the management of patients with ICH.

Inter-rater agreement on identification of electrographic seizures and periodic discharges in ICU EEG recordings

OBJECTIVE

This study investigated inter-rater agreement (IRA) among EEG experts for the identification of electrographic seizures and periodic discharges (PDs) in continuous ICU EEG recordings.

METHODS

Eight board-certified EEG experts independently identified seizures and PDs in thirty 1-h EEG segments which were selected from ICU EEG recordings collected from three medical centers. IRA was compared between seizure and PD identifications, as well as among rater groups that have passed an ICU EEG Certification Test, developed by the Critical Care EEG Monitoring Research Consortium (CCEMRC).

RESULTS

Both kappa and event-based IRA statistics showed higher mean values in identification of seizures compared to PDs (k=0.58 vs. 0.38; p<0.001). The group of rater pairs who had both passed the ICU EEG Certification Test had a significantly higher mean IRA in comparison to rater pairs in which neither had passed the test.

CONCLUSIONS

IRA among experts is significantly higher for identification of electrographic seizures compared to PDs. Additional instruction, such as the training module and certification test developed by the CCEMRC, could enhance this IRA.

SIGNIFICANCE

This study demonstrates more disagreement in the labeling of PDs in comparison to seizures. This may be improved by education about standard EEG nomenclature.

[French guidelines on electroencephalogram]

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

Risk factors for post-stroke seizures: a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis to identify risk factors associated with early seizure (ES) or late seizure (LS) onset in adults following stroke.

DATA SOURCES

Electronic databases (MEDLINE and EMBASE), archives of stroke or epilepsy patients, and bibliographies of relevant articles, which were written in English.

STUDY SELECTION

We included studies published since 1990 that reported the stroke and seizure outcomes of adult patients during follow-up. We independently performed title, abstract and full-text screening and resolved disagreements through discussion.

DATA EXTRACTION

Two authors performed the data extraction. We recorded all possible risk factors predictive of seizure onset.

DATA SYNTHESIS

We used odds ratios (ORs) or the mean difference (MD) to compare the pooled rates of seizure onset between the exposed group and the non-exposed group. All meta-analyses were performed with Review Manager Software.

RESULTS

Intracerebral hemorrhage (OR=1.88, 95% CI=1.43-2.47), cerebral infarction with hemorrhagic transformation (OR=3.28, 95% CI=2.09-5.16), stroke severity (OR=3.10, 95% CI=2.00-4.81, p<0.01, I(2)=0%; MD=3.98, 95% CI=1.06-6.90, p<0.01), and alcoholism (OR=1.70, 95% CI=1.23-2.34, p<0.01) were associated with a significantly greater probability of ES occurrence. There were significant effects of cortical involvement (OR=2.50, 95% CI=1.93-3.23) and stroke severity (MD=5.72, 95% CI=4.23-7.22, p<0.01, I(2)=0) on LS onset. However, there was no significant difference in the probability of single LS episode between patients with intracerebral hemorrhage and infarction stroke (OR=1.20, 95% CI=0.92-1.55).

CONCLUSIONS

Evidence suggests that cortical involvement, stroke subtypes and stroke severity are significant predictors of seizure onset following stroke. However, we did not find a significant difference in the rate of onset of single LS episodes between patients with intracerebral hemorrhage and cerebral infarction.

Clinical practice guidelines for the medical and surgical management of primary intracerebral hemorrhage in Korea

The purpose of this clinical practice guideline (CPG) is to provide current and comprehensive recommendations for the medical and surgical management of primary intracerebral hemorrhage (ICH). Since the release of the first Korean CPGs for stroke, evidence has been accumulated in the management of ICH, such as intracranial pressure control and minimally invasive surgery, and it needs to be reflected in the updated version. The Quality Control Committee at the Korean Society of cerebrovascular Surgeons and the Writing Group at the Clinical Research Center for Stroke (CRCS) systematically reviewed relevant literature and major published guidelines between June 2007 and June 2013. Based on the published evidence, recommendations were synthesized, and the level of evidence and the grade of the recommendation were determined using the methods adapted from CRCS. A draft guideline was scrutinized by expert peer reviewers and also discussed at an expert consensus meeting until final agreement was achieved. CPGs based on scientific evidence are presented for the medical and surgical management of patients presenting with primary ICH. This CPG describes the current pertinent recommendations and suggests Korean recommendations for the medical and surgical management of a patient with primary ICH.

Continuous EEG monitoring: a survey of neurophysiologists and neurointensivists

OBJECTIVE

Continuous EEG monitoring (cEEG) of critically ill adults is being used with increasing frequency, and practice guidelines on indications for cEEG monitoring have recently been published. However, data describing the current practice of cEEG in critically ill adults is limited. We aimed to describe the current practice of cEEG monitoring in adults in the United States.

METHODS

A survey assessing cEEG indications and procedures was sent to one intensivist and one neurophysiologist responsible for intensive care unit (ICU) cEEG at 151 institutions in the United States. At some institutions only one physician could be identified.

RESULTS

One hundred thirty-seven physicians from 97 institutions completed the survey. Continuous EEG is utilized by nearly all respondents to detect nonconvulsive seizures (NCS) in patients with altered mental status following clinical seizures, intra cerebral hemorrhage (ICH), traumatic brain injury, and cardiac arrest, as well as to characterize abnormal movements suspected to be seizures. The majority of physicians monitor comatose patients for 24-48 h. In an ideal situation with unlimited resources, 18% of respondents would increase cEEG duration. Eighty-six percent of institutions have an on-call EEG technologist available 24/7 for new patient hookups, but only 26% have technologists available 24/7 in-house. There is substantial variability in who reviews EEG and how frequently it is reviewed as well as use of quantitative EEG.

SIGNIFICANCE

Although there is general agreement regarding the indications for ICU cEEG, there is substantial interinstitutional variability in how the procedure is performed.

Subarachnoid extension of hemorrhage is associated with early seizures in primary intracerebral hemorrhage

BACKGROUND

Seizures are common in patients with subarachnoid hemorrhage, potentially by inciting cortical irritability. Seizures are also commonly seen after intracerebral hemorrhage (ICH), although the mechanisms and risk factors within that population are not well understood. The objective of this study is to evaluate whether subarachnoid hemorrhage extension (SAHE) is associated with early seizures in patients with primary ICH.

METHODS

Patients with primary ICH were enrolled into a prospective registry between December 2006 and July 2012. Patients were managed per a structured protocol. SAHE was identified on imaging by expert reviewers blinded to outcomes. Electroencephalograms were routinely obtained in patients with unexplained, poor level of arousal. Seizure was determined by clinically observed convulsions or traditional electroencephalographic criteria. Early seizures were defined as occurring within 3 days of hemorrhage. A binary logistic regression model was developed to test whether the occurrence of SAHE was independently associated with seizures.

RESULTS

A total of 234 patients were studied. Of these, 93 (40%) had SAHE and 9 (4%) had early seizures. SAHE was associated with early seizures (P = .03). No additional variables were identified by regression modeling to mediate the association between SAHE and early seizures (odds ratio 5.62 [95% confidence interval 1.14-27.7], P = .034).

CONCLUSIONS

SAHE is associated with early seizures in patients with primary ICH. Further study is needed to confirm these findings and determine whether modifications to routine care based on the presence of SAHE would be of benefit.

Diagnostic yield of electroencephalography in the medical and surgical intensive care unit

BACKGROUND

To determine the incidence of electrographic seizures during continuous electroencephalography (cEEG) in the medical and surgical ICU.

METHODS

We retrospectively reviewed the records of all adults who underwent cEEG in our medical and surgical ICU over a 4.5 year period. Patients with acute brain injury were excluded. Our primary outcome was cEEG documentation of an electrographic seizure, defined as a rhythmic discharge or spike and wave pattern demonstrating definite evolution and lasting at least 10 s. To assess inter-rater variability in cEEG interpretation, two electrophysiologists independently reviewed all available cEEGs of subjects with electrographic seizures documented on their clinical cEEG report and those of an equal number of randomly selected subjects from the remaining cohort.

RESULTS

Kappa analysis showed a value of 0.88, indicating excellent inter-rater agreement. Electrographic seizures were identified in 12 of 105 patients (11 %, 95 % CI 5-18 %). This rate did not change after excluding patients with a history of seizure, remote brain injury, or seizure-like events before cEEG. In an ordinal logistic regression model controlling for age, sex, and SOFA score, electrographic seizures were associated with lower odds of good outcomes on the Glasgow Outcome Scale at discharge (OR 0.3, 95 % CI 0.1-0.8).

CONCLUSION

In a tertiary care medical and surgical ICU, electrographic seizures were seen on 11 % of cEEGs ordered for the evaluation of encephalopathy, and were associated with worse functional outcomes at discharge. Our findings confirm the results of a prior study suggesting a substantial burden of electrographic seizures in critically ill encephalopathic patients.

The probability of seizures during EEG monitoring in critically ill adults

OBJECTIVE

To characterize the risk for seizures over time in relation to EEG findings in hospitalized adults undergoing continuous EEG monitoring (cEEG).

METHODS

Retrospective analysis of cEEG data and medical records from 625 consecutive adult inpatients monitored at a tertiary medical center. Using survival analysis methods, we estimated the time-dependent probability that a seizure will occur within the next 72-h, if no seizure has occurred yet, as a function of EEG abnormalities detected so far.

RESULTS

Seizures occurred in 27% (168/625). The first seizure occurred early (<30min of monitoring) in 58% (98/168). In 527 patients without early seizures, 159 (30%) had early epileptiform abnormalities, versus 368 (70%) without. Seizures were eventually detected in 25% of patients with early epileptiform discharges, versus 8% without early discharges. The 72-h risk of seizures declined below 5% if no epileptiform abnormalities were present in the first two hours, whereas 16h of monitoring were required when epileptiform discharges were present. 20% (74/388) of patients without early epileptiform abnormalities later developed them; 23% (17/74) of these ultimately had seizures. Only 4% (12/294) experienced a seizure without preceding epileptiform abnormalities.

CONCLUSIONS

Seizure risk in acute neurological illness decays rapidly, at a rate dependent on abnormalities detected early during monitoring. This study demonstrates that substantial risk stratification is possible based on early EEG abnormalities.

SIGNIFICANCE

These findings have implications for patient-specific determination of the required duration of cEEG monitoring in hospitalized patients.

The CAVE score for predicting late seizures after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Seizures are a common complication of intracerebral hemorrhage (ICH). We developed a novel tool to quantify this risk in individual patients.

METHODS

Retrospective analysis of the observational Helsinki ICH Study (n=993; median follow-up, 2.7 years) and the Lille Prognosis of InTra-Cerebral Hemorrhage (n=325; 2.2 years) cohorts of consecutive ICH patients admitted between 2004 and 2010. Helsinki ICH Study patients' province-wide electronic records were evaluated for early seizures occurring within 7 days of ICH and among 7-day survivors (n=764) for late seizures (LSs) occurring >7 days from ICH. A Cox regression model estimating risk of LSs was used to derive a prognostic score, validated in the Prognosis of InTra-Cerebral Hemorrhage cohort.

RESULTS

Of the Helsinki ICH Study patients, 109 (11.0%) had early seizures within 7 days of ICH. Among the 7-day survivors, 70 (9.2%) patients developed LSs. The cumulative risk of LSs was 7.1%, 10.0%, 10.2%, 11.0%, and 11.8% at 1 to 5 years after ICH, respectively. We created the CAVE score (0-4 points) to estimate the risk of LSs, with 1 point for each of cortical involvement, age<65 years, volume>10 mL, and early seizures within 7 days of ICH. The risk of LSs was 0.6%, 3.6%, 9.8%, 34.8%, and 46.2% for CAVE scores 0 to 4, respectively. The c-statistic was 0.81 (0.76-0.86) and 0.69 (0.59-0.78) in the validation cohort.

CONCLUSIONS

One in 10 patients will develop seizures after ICH. The risk of this adverse outcome can be estimated by a simple score based on baseline variables.

Nonconvulsive seizures in subarachnoid hemorrhage link inflammation and outcome

OBJECTIVE

Nonconvulsive seizures (NCSz) are frequent following acute brain injury and have been implicated as a cause of secondary brain injury, but mechanisms that cause NCSz are controversial. Proinflammatory states are common after many brain injuries, and inflammation-mediated changes in blood-brain barrier permeability have been experimentally linked to seizures.

METHODS

In this prospective observational study of aneurysmal subarachnoid hemorrhage (SAH) patients, we explored the link between the inflammatory response following SAH and in-hospital NCSz studying clinical (systemic inflammatory response syndrome [SIRS]) and laboratory (tumor necrosis factor receptor 1 [TNF-R1], high-sensitivity C-reactive protein [hsCRP]) markers of inflammation. Logistic regression, Cox proportional hazards regression, and mediation analyses were performed to investigate temporal and causal relationships.

RESULTS

Among 479 SAH patients, 53 (11%) had in-hospital NCSz. Patients with in-hospital NCSz had a more pronounced SIRS response (odds ratio [OR]=1.9 per point increase in SIRS, 95% confidence interval [CI]=1.3-2.9), inflammatory surges were more likely immediately preceding NCSz onset, and the negative impact of SIRS on functional outcome at 3 months was mediated in part through in-hospital NCSz. In a subset with inflammatory serum biomarkers, we confirmed these findings linking higher serum TNF-R1 and hsCRP to in-hospital NCSz (OR=1.2 per 20-point hsCRP increase, 95% CI=1.1-1.4; OR=2.5 per 100-point TNF-R1 increase, 95% CI=2.1-2.9). The association of inflammatory biomarkers with poor outcome was mediated in part through NCSz.

INTERPRETATION

In-hospital NCSz were independently associated with a proinflammatory state following SAH as reflected in clinical symptoms and serum biomarkers of inflammation. Our findings suggest that inflammation following SAH is associated with poor outcome and that this effect is at least in part mediated through in-hospital NCSz.

Seizures in the acute stroke setting

Stroke is one of the leading causes of long-term disability. One in six people in the world will suffer a stroke in their lifetime, with the annual incidence about 117 per 100,000 person-years in developing countries. It has also been shown to be the cause of 10-15% of epilepsies, more prevalent in patients above 60 years of age. The incidence of early seizures in acute stroke ranges 3-33%, with 50-78% of the seizures occurring within the first 24 hours. Occurrence of seizures within 24 hours of stroke is associated with higher 30-day mortality, which may be a reflection of severe neuronal damage. Alteration in intracellular ion concentrations and hyper-excitability are thought to be etiologies for early seizures in acute stroke, and the increased stress on already vulnerable tissues may result in worsening of stroke symptoms. Early detection of seizures and subsequent effective treatment can prevent additional metabolic burden and damage to the blood-brain barrier, which may improve recovery and overall outcome. Clinical seizures can be recognized readily at bedside and lead to prompt medical intervention. In contrast, electrographic seizures with subtle or no clinical sign and non-convulsive status epilepticus (NCSE) may escape clinical observation and be left untreated. With the use of continuous electroencephalogram monitoring (cEEG), patients with electrographic seizures can be better identified and medically treated more quickly. In addition to electrographic seizures, the presence of isolated and periodic epileptiform patterns on electroencephalogram (EEG) suggests the need for medical treatment since up to 75% of these patients have been found to develop early post-stroke seizures. Newer anti-epileptic medications with intravenous formulation, together with traditional regimen and barbiturate, have shown promise in controlling early post-stroke seizures and possibly improving outcome.

Rhythmical and periodic EEG patterns do not predict short-term outcome in critically ill patients with subarachnoid hemorrhage

INTRODUCTION

Nonconvulsive seizures and nonconvulsive status epilepticus commonly occur in patients with aneurysmal subarachnoid hemorrhages. When continuous EEG is used in patients in the neuro-intensive care unit, rhythmical and periodic patterns of uncertain significance are frequently encountered. It is unknown how these findings impact patient outcome.

METHODS

Patients were enrolled from a single tertiary care center with subarachnoid hemorrhages secondary to ruptured intracranial aneurysm, and either a witnessed seizure or significantly impaired mental status. Prospective clinical, laboratory, imaging, and short-term outcome data were collected. Continuous EEG monitoring was performed and scored according to American Clinical Neurophysiology Society (ACNS) Subcommittee on Research Terminology for Continuous EEG Monitoring.

RESULTS

Sixty-eight patients were enrolled. Fifty-four had a poor-grade subarachnoid hemorrhage upon admission. Fifty-one patients had rhythmical or periodic patterns: 33 with periodic discharges and 38 with rhythmic delta activity. Four patients had unequivocal electrographic seizures. Patients did poorly in the short term: 14 died and 42 were severely disabled at discharge. In hospital, mortality was 19.6% in patients with rhythmical or periodic patterns and 23.5% in patients without. Age, female gender, and endovascular treatment had a positive correlation with the occurrence of periodic discharges. However, there was no correlation between rhythmical and periodic patterns and outcome.

DISCUSSION

Using the ACNS Research Terminology, it is shown that rhythmical and periodic patterns are very common in critically ill patients with subarachnoid hemorrhage. However, the presence and the abundance of these patterns did not predict short-term outcome in this prospective, single-center observational study. We were unable to show that rhythmical and periodic EEG patterns are an independent predictor for outcome relative to other clinical features. Large multicenter studies will be required to determine if these patterns independently predict outcome and to demonstrate the impact of treatment interventions that are directed at rhythmical and periodic continuous EEG patterns.