Prolonged electroencephalogram monitoring for seizures and their treatment

Neonatal Seizures

Neonatal seizures are common among patients with acute brain injury or critical illness and can be difficult to diagnose and treat. The most common etiology of neonatal seizures is hypoxic-ischemic encephalopathy, with other common causes including ischemic stroke and intracranial hemorrhage. Neonatal clinicians can use a standardized approach to patients with suspected or confirmed neonatal seizures that entails laboratory testing, neuromonitoring, and brain imaging. The primary goals of management of neonatal seizures are to identify the underlying cause, correct it if possible, and prevent further brain injury. This article reviews recent evidence-based guidelines for the treatment of neonatal seizures and discusses the long-term outcomes of patients with neonatal seizures.

EEG in neonatal seizures: where to look and what to see

INTRODUCTION

Neonatal seizures are frequent and carry a detrimental prognostic outlook. Diagnosis is based on EEG confirmation. Classification has recently changed.

AREAS COVERED

We consulted original papers, book chapters, atlases, and reviews to provide a narrative overview on EEG characteristics of neonatal seizures. We searched PubMed, without time restrictions (last visited: 31 May 2022). Additional papers were extracted from the references list of selected papers. We describe the typical neonatal ictal EEG discharges morphology, location, and propagation, together with age-dependent features. Etiology-dependent electroclinical features, when identifiable, are presented for both acute symptomatic neonatal seizures and neonatal-onset epilepsies and developmental/epileptic encephalopathies. The few ictal variables known to predict long-term outcome have been discussed.

EXPERT OPINION

Multimodal neuromonitoring in critically ill newborns, high-density EEG, and functional neuroimaging might increase our insight into the neurophysiological bases of seizures in newborns. Increasing availability of long-term monitoring with conventional video-EEG and automated detection methods will allow clinicians and researchers to gather an ever expanding bulk of clinical and neurophysiological data to enhance accuracy with deep phenotyping. The latest classification proposal represents an input for critically revising our diagnostic abilities with respect to seizure definition, duration, and semiology, possibly further promoting clinical research.

Early Electroencephalogram Background Could Guide Tailored Duration of Monitoring for Neonatal Encephalopathy Treated with Therapeutic Hypothermia

OBJECTIVE

To evaluate whether features of the early electroencephalographic (EEG) background could guide the optimal duration of continuous video EEG monitoring for seizure detection in newborn infants treated with therapeutic hypothermia for hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

Retrospective cohort study of 114 consecutive infants treated with therapeutic hypothermia for moderate to severe HIE at a level IV neonatal intensive care unit (NICU) between 2012 and 2018. All infants were monitored with continuous video EEG through cooling and rewarming. Archived samples from the first 24 hours of these EEG traces were reviewed systematically and classified by background characteristics.

RESULTS

Electrographic seizures occurred in 56 of the 114 infants (49%). Seizure onset was within the first 24 hours after initiation of continuous video EEG in 49 if these 56 infants (88%), between 24 and 48 hours in 4 infants (7%), and >72 hours in 3 infants (5%). Infants with a normal or mildly abnormal EEG background either had seizure onset within the first 24 hours or never developed seizures. Four patients with seizure onset between 24 and 48 hours had markedly abnormal EEG backgrounds. The 3 patients with seizure onset beyond 72 hours had moderate or severely abnormal early continuous video EEG backgrounds.

CONCLUSIONS

The use of early continuous video EEG background categorization may be appropriate to guide the duration of continuous video EEG for infants with HIE treated with therapeutic hypothermia. Some infants may reasonably be monitored for 24 hours rather than throughout cooling and rewarming without a significant risk of missed seizures. This could have significant implications for continuous video EEG resource utilization.

Perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke is a relatively common and serious neurologic disorder that can affect the fetus, the preterm, and the term-born infant. It carries significant long-term disabilities. Herein we describe the current understanding of its etiology, pathophysiology and classification, different presentations, and optimal early management. We discuss the role of different brain imaging modalities in defining the extent of lesions and the impact this has on the prediction of outcomes. In recent years there has been progress in treatments, making early diagnosis and the understanding of likely morbidities imperative. An overview is given of the range of possible outcomes and optimal approaches to follow-up and support for the child and their family in the light of present knowledge.

Seizure classification, etiology, and management

The first weeks of life are a time of heightened risk for seizures due to age-dependent physiologic features of the developing brain that lead to increased neuronal excitation and decreased inhibition. Usually, seizures in neonates are a symptom of an acute brain injury; seizures are only rarely due to neonatal-onset epilepsy syndromes. Neonatal seizures are harmful to the developing brain; early and accurate diagnosis is critical. For suspected seizures, EEG monitoring should be initiated as soon as is feasible, in order to evaluate for events of concern, screen for subclinical seizures, and assess the EEG background. Amplitude-integrated EEG can provide excellent complementary data, particularly with regard to evolution of background patterns, but has limited sensitivity to detect individual neonatal seizures. An urgent and systematic approach to precise etiologic diagnosis is key for optimal management and estimates of prognosis. Evaluation of the seizure etiology must occur in parallel with initiation of appropriate treatment. It is critical that neonatologists and neurologists develop hospital-specific, consensus-based practice pathways for neonatal seizure evaluation and treatment. Such practice pathways can streamline medical decision making, facilitate rapid medication administration, and potentially decrease seizure burden and optimize outcomes. Herein, the pathophysiology, epidemiology, treatment, and long-term management considerations for neonatal seizures are presented.

Symptomatic seizures in preterm newborns: a review on clinical features and prognosis

Neonatal seizures are the most common neurological event in newborns, showing higher prevalence in preterm than in full-term infants. In the majority of cases they represent acute symptomatic phenomena, the main etiologies being intraventricular haemorrhage, hypoxic-ischemic encephalopathy, central nervous system infections and transient metabolic derangements.Current definition of neonatal seizures requires detection of paroxysmal EEG-changes, and in preterm newborns the incidence of electrographic-only seizures seems to be particularly high, further stressing the crucial role of electroencephalogram monitoring in this population. Imaging work-up includes an integration of serial cranial ultrasound and brain magnetic resonance at term-equivalent age. Unfavourable outcomes following seizures in preterm infants include death, neurodevelopmental impairment, epilepsy, cerebral palsy, hearing and visual impairment. As experimental evidence suggests a detrimental role of seizures per se in determining subsequent outcome, they should be promptly treated with the aim to reduce seizure burden and long-term disabilities. However, neonatal seizures show low response to conventional anticonvulsant drugs, and this is even more evident in preterm newborns, due to intrinsic developmental factors. As a consequence, as literature does not provide any specific guidelines, due to the lack of robust evidence, off-label medications are often administered in clinical practice.

Short-Term Effects of Phenobarbitone on Electrographic Seizures in Neonates

BACKGROUND

Phenobarbitone is the most common first-line anti-seizure drug and is effective in approximately 50% of all neonatal seizures.

OBJECTIVE

To describe the response of electrographic seizures to the administration of intravenous phenobarbitone in neonates using seizure burden analysis techniques.

METHODS

Multi-channel conventional EEG, reviewed by experts, was used to determine the electrographic seizure burden in hourly epochs. The maximum seizure burden evaluated 1 h before each phenobarbitone dose (T-1) was compared to seizure burden in periods of increasing duration after each phenobarbitone dose had been administered (T+1, T+2 to seizure offset). Differences were analysed using linear mixed models and summarized as means and 95% CI.

RESULTS

Nineteen neonates had electrographic seizures and met the inclusion criteria for the study. Thirty-one doses were studied. The maximum seizure burden was significantly reduced 1 h after the administration of phenobarbitone (T+1) [-14.0 min/h (95% CI: -19.6, -8.5); p < 0.001]. The percentage reduction was 74% (IQR: 36-100). This reduction was temporary and not significant within 4 h of administrating phenobarbitone. Subgroup analysis showed that only phenobarbitone doses at 20 mg/kg resulted in a significant reduction in the maximum seizure burden from T-1 to T+1 (p = 0.002).

CONCLUSIONS

Phenobarbitone significantly reduced seizures within 1 h of administration as assessed with continuous multi-channel EEG monitoring in neonates. The reduction was not permanent and seizures were likely to return within 4 h of treatment.

Continuous Video Electroencephalographic (EEG) Monitoring for Electrographic Seizure Diagnosis in Neonates: A Single-Center Study

The objective of this study was to determine the diagnostic yield of continuous video electroencephalographic (EEG) monitoring in critically ill neonates in the setting of a novel, university-based Neonatal Neurocritical Care Service. Patient demographic characteristics, indication for seizure monitoring, and presence of electrographic seizures were obtained by chart review. Among 595 patients cared for by the Neonatal Neurocritical Care Service, 400 (67%) received continuous video EEG. The median duration of continuous video EEG monitoring was 49 (interquartile range = 22-87) hours. Electrographic seizures were captured in 105 of 400 (26% of monitored patients) and of those, 25 of 105 (24%) had no clinical correlate. In addition, 52 of 400 subjects (13%) were monitored due to paroxysmal events concerning for seizures, but never had electrographic seizures. Continuous video EEG monitoring helped confirm or rule out ongoing seizures in more than one-third of the cases. This finding helps to support the use of continuous video EEG in critically ill neonates.

Neonatal seizures in hypoxic-ischaemic encephalopathy--risks and benefits of anticonvulsant therapy

The risk of seizures is at its highest during the neonatal period, and the most common cause of neonatal seizures is hypoxic-ischaemic encephalopathy (HIE). This enhanced vulnerability is caused by an imbalance in the expression of receptors for excitatory and inhibitory neurotransmission, which is age dependent. There has been progress in detecting the electrophysiological abnormalities associated with seizures using amplitude-integrated electroencephalography (aEEG). Data from animal studies indicate a variety of risk factors for seizures, but there are limited clinical data looking at the long-term neurodevelopmental consequences of seizures alone. Neonatal seizures are also associated with increased risk of further epileptic seizures; however, it is less clear whether or not this results from an underlying pathology, and whether or not seizures confer additional risk. Phenobarbital and phenytoin are still the first-line antiepileptic drugs (AEDs) used to treat neonatal seizures, although they are effective in only one-third of affected infants. Furthermore, based on findings from animal studies, there are concerns regarding the risks associated with using these AEDs. Clinicians face a difficult challenge because, although seizures can be easily identified using aEEG, treatment options are limited, and there are uncertainties regarding treatment outcomes. There is a need to obtain long-term follow-up data, comparing groups of infants treated with or without current therapies. If these analyses indicate a definite benefit of treating neonatal seizures, then novel therapeutic approaches should be developed.

Early postnatal EEG features of perinatal arterial ischaemic stroke with seizures

Background

Stroke is the second most common cause of seizures in term neonates and is associated with abnormal long-term neurodevelopmental outcome in some cases.

Objective

To aid diagnosis earlier in the postnatal period, our aim was to describe the characteristic EEG patterns in term neonates with perinatal arterial ischaemic stroke (PAIS) seizures.

Design

Retrospective observational study.

Patients

Neonates >37 weeks born between 2003 and 2011 in two hospitals.

Method

Continuous multichannel video-EEG was used to analyze the background patterns and characteristics of seizures. Each EEG was assessed for continuity, symmetry, characteristic features and sleep cycling; morphology of electrographic seizures was also examined. Each seizure was categorized as electrographic-only or electroclinical; the percentage of seizure events for each seizure type was also summarized.

Results

Nine neonates with PAIS seizures and EEG monitoring were identified. While EEG continuity was present in all cases, the background pattern showed suppression over the infarcted side; this was quite marked (>50% amplitude reduction) when the lesion was large. Characteristic unilateral bursts of theta activity with sharp or spike waves intermixed were seen in all cases. Sleep cycling was generally present but was more disturbed over the infarcted side. Seizures demonstrated a characteristic pattern; focal sharp waves/spike-polyspikes were seen at frequency of 1–2 Hz and phase reversal over the central region was common. Electrographic-only seizure events were more frequent compared to electroclinical seizure events (78 vs 22%).

Conclusions

Focal electrographic and electroclinical seizures with ipsilateral suppression of the background activity and focal sharp waves are strong indicators of PAIS. Approximately 80% of seizure events were the result of clinically unsuspected seizures in neonates with PAIS. Prolonged and continuous multichannel video-EEG monitoring is advocated for adequate seizure surveillance.

Diagnosing neonatal seizures and status epilepticus

Continuous electroencephalographic (CEEG) monitoring is often applied in the Neonatal Intensive Care Unit to aid in the diagnosis and management of seizures. Neonatal seizures are particularly difficult to identify on the basis of clinical observation alone; diagnosis is greatly facilitated by CEEG monitoring. There is building evidence to suggest which neonates are at highest risk for seizures, and how CEEG can aid diagnosis. For the neurophysiologist, the unique features of neonatal seizures can distinguish them from nonictal patterns. These features include duration, location, morphology, and evolution. At the extreme, very frequent or prolonged neonatal seizures constitute status epilepticus. There is no consensus definition for neonatal status epilepticus, although the proposed criteria share some features. This article reviews available evidence to guide the application and interpretation of CEEG in the diagnosis of neonatal seizures and status epilepticus.

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

PURPOSE

To evaluate amplitude-integrated EEG (aEEG) in comparison with conventional (cEEG) for the identification of electrographic seizures in neonates with acute neonatal encephalopathies.

METHODS

Thirty-one conventional cEEG/aEEG long-term recordings from twenty-eight newborns were reviewed in order to assess the electrographic seizure detection rate and recurrence in newborns. Two paediatric neurologists and one neonatologist, blinded to the raw full array cEEG, were asked to mark any events suspected to be an electrographic seizures on aEEG. They were asked to decide if the displayed aEEG trace showed the pattern of a single seizure (SS), repetitive seizures (RS) or status epilepticus (SE). Their ability to recognize electrographic seizures on aEEG was compared to seizures identified on full array cEEG.

RESULTS

25 of the 31 long-term cEEGs recordings showed electrographic seizures. The two paediatric neurologists and the neonatologist identified SE in 100% of the reviewed traces using aEEG alone while they identified 49.4% and 37.5% of electrographic seizures using aEEG alone. Overall, the correct identification ranged from 23.5% to 30.7% for SS and 66% for RS. The inter-observer agreement (k) for the identification of SE for the two paediatric neurologists and the neonatologist was 1.0. Overall the inter-observer agreement (k) for the detection of SS, RS and SE of the two paediatric neurologists was 0.91.

CONCLUSIONS

In our study the observers identified SE in 100% of the reviewed traces using raw aEEG alone, thus aEEG might represent a useful tool to detect SE in the setting of NICU. SS may not be reliably identified using aEEG alone. Simultaneous recording of the raw cEEG/aEEG provides a good level of sensitivity for the detection of neonatal electrographic seizures.

Neonatal seizures and status epilepticus

Neonatal seizures are common, often require EEG monitoring for diagnosis and management, may be associated with worse neurodevelopmental outcome, and can often be treated with existing anticonvulsants. A neonatal electrographic seizure is defined as a sudden, repetitive, evolving, and stereotyped event of abnormal electrographic pattern with amplitude of at least 2 μV and a minimum duration of 10 seconds. The diagnosis of neonatal seizures relies heavily on the neurophysiologist's interpretation of EEG. Consideration of specific criteria for the definition of a neonatal seizure, including seizure duration, location, morphology, evolution, semiology, and overall seizure burden, has utility for both the clinician and the researcher. The importance of EEG in the diagnosis and management of neonatal seizures, the electrographic characteristics of neonatal seizures, the impact of neonatal seizures on outcome, and tools to aid in the identification of neonatal seizures are reviewed.

Clinical management of seizures in newborns : diagnosis and treatment

Neonatal seizures can be classified as tonic, clonic, myoclonic, and subtle. A clinical diagnosis is not easy as seizures are usually subtle in neonates. In the majority of newborn infants seizures are subclinical. On the other hand, not all abnormal movements identified by clinicians as clinical seizures are accompanied by electroencephalographic seizure discharges in the EEG. Precise incidence is difficult to delineate and depends on study population and criteria used for diagnosis of seizures. Controversy exists as to whether neonatal seizures themselves cause damage to the developing brain, or if the damage is primarily due to the underlying cause of the seizures. As a result of this controversy there is ongoing discussion whether all seizures (both clinical and subclinical) should be treated. In addition, when (sub)clinical seizures are treated, there is no consensus about the most appropriate treatment for neonatal seizures and how to assess the efficacy of treatment. Current therapeutic options to treat neonatal seizures (i.e. primarily first-generation antiepileptic drugs [AEDs]) are relatively ineffective. In practice, phenobarbital still remains the drug of first choice for EEG confirmed or suspected seizures. Benzodiazepines are also used in (phenobarbital) refractory cases. Several (small) studies indicate that lidocaine is an effective drug for refractory seizures as second- or third-line treatment. Although data are scarce, some AEDs with a wide acceptance in adult and pediatric neurology practice are being used to treat neonatal seizures (i.e. second-generation AEDs). These drugs are chemically different from all first-generation AEDs and they have an effect on other pathways so they provide new pharmacological targets for controlling seizures in newborns. Levetiracetam, topiramate, felbamate, bumetanide, lamotrigine and vigabatrin are examples of these second-generation AEDs. There is an urgent need for prospective, randomized, controlled trials to assess the efficacy and safety of these second-generation AEDs in neonates. The aim of this review is to provide an overview of the current knowledge of diagnosis, the effect on brain injury, and the treatment of neonatal seizures.

Neonatal seizures: treatment practices among term and preterm infants

Neonatal seizures are common clinical conditions in both term and preterm neonates, yet no clinical management guidelines for direct care exist. We surveyed 193 international neurologists, neonatologists, and specialists in neonatal neurology or neonatal neurocritical care to assess management practices for seizures in preterm and term neonates. We found high reported rates of electroencephalogram and amplitude-integrated electroencephalogram (aEEG) monitoring to detect neonatal seizures, prevalent use of older anticonvulsant agents, and high rates of neuroimaging. Overall, responses were similar for term and preterm neonates. However, term neonates were likelier to be more heavily investigated, with higher use of magnetic resonance imaging and of electroencephalogram and aEEG monitoring of at-risk neonates. Continuous monitoring and cranial imaging of neonatal seizures now comprise the standard of care in many centers, although management practices vary widely. Early recognition and management of neonatal seizures and possible underlying injury may lead to increased opportunities for stopping seizures, protecting the brain, and improving developmental outcomes in at-risk neonates. The need for collaboration among neonatologists and neurologists is urgent, to address gaps in knowledge regarding management of neonatal seizures in term and preterm neonates.

Diagnostic value of amplitude-integrated electroencephalogram in neonatal seizures

OBJECTIVE To investigate the accuracy of amplitude-integrated electroencephalography (aEEG) in detecting full-term neonatal seizures. METHODS Conventional EEG (cEEG) and aEEG were simultaneously applied to 62 full-term newborns with seizures and results were analyzed with different methods. RESULTS Of 876 seizures confirmed by cEEG, 21% were detected by clinical observation, 44.4% by aEEG and 85.7% by aEEG plus C3/C4 raw EEG. Of 531 seizures with a frequency higher than 5 times/h, 52.5% were detected by aEEG and 96.8% by aEEG plus C3/C4 raw EEG. Of 510 seizures lasting longer than 60 s, 50.6% were diagnosed by aEEG and 84.1% by aEEG plus C3/C4 raw EEG. Of 509 seizures originating in the central region, 57.9% were detected by aEEG and 90.9% by aEEG plus C3/C4 raw EEG. CONCLUSION Combination of aEEG with cEEG offers more accurate diagnosis, especially for detecting high-frequency, long-lasting and central region-generated seizures.

Brief electroencephalography rhythmic discharges (BERDs) in the neonate with seizures: their significance and prognostic implications

We aimed to explore the significance and prognostic implications of paroxysmal brief electroencephalography (EEG) rhythmic discharges (BERDs) in neonatal seizures. The 52 neonates in this study were divided into 3 groups: (1) BERDs only: 9 neonates, (2) BERDs + conventional EEG seizures: 11 babies, (3) Conventional EEG seizures only: 32 babies. We analyzed the BERDs and compared outcomes in the 3 groups: there was no significant difference in mortality and neurodevelopmental or background EEG impairment. Similar to conventional EEG seizures, BERDs are also associated with an increased mortality, morbidity, and EEG background abnormalities. Fewer babies with BERDS appear to develop postneonatal seizures suggesting their epileptogenic potential is less. In the appropriate clinical context, BERDs should be considered as miniseizures.

Neurocritical care for neonates

OPINION STATEMENT

Neurocritical care is an emerging subspecialty that combines expertise in neurology, critical care medicine, neuroradiology, and neurosurgery. Increasing evidence from the adult literature suggests that specialized neurocritical care can lead to improved outcomes following acute brain injury. Critically ill neonates with neurologic conditions may also benefit from specialized neurocritical care. Adherence to guidelines and managing patients in intensive care nurseries with dedicated, multidisciplinary neurocritical care personnel may optimize outcomes. This goal may be achieved by more quickly recognizing neurologic impairment, preventing secondary brain injury by maintaining basic physiologic functions, and rapidly implementing therapies. Nurseries that care for neonates with suspected acute brain injury should be prepared to adequately support multiorgan involvement, monitor the brain to detect seizures, evaluate for brain injury using MRI, and follow development through school age.

Treatment of hypoxic-ischemic encephalopathy in newborns

Hypoxic-ischemic (HI) brain injury is the most common cause of encephalopathy and seizures in term newborn infants. There is no single, valid test for birth asphyxia leading to HI brain injury, and thus this disorder is often poorly characterized, and the timing and etiology of the injury can be difficult to ascertain. Optimal management of HI brain injury involves prompt resuscitation, careful supportive care including prevention of hyperthermia and hypoglycemia, and treatment of clinical and frequent or prolonged subclinical seizures. Recent evidence suggests that therapeutic hypothermia by selective head or whole-body cooling administered within 6 hours of birth reduces the incidence of death or moderate/severe disability at 12 to 22 months. Hypothermia is a promising new therapy that physicians should consider within the context of a registry or study. Optimal seizure treatment remains controversial because the most widely used drug, phenobarbital, has limited efficacy, and the value of monitoring and treating subclinical seizures is uncertain. There is compelling need for well-designed clinical trials to address treatment of ongoing brain injury in the setting of hypoxia-ischemia and seizures. Emerging evidence from preclinical studies suggests that future therapy for HI brain injury and neonatal encephalopathy will combine novel neuroprotective and anti-seizure agents. Pilot clinical trials of newer anticonvulsants are ongoing and will provide critical information for care of neonatal seizures.

Ictal electroencephalograms in neonatal seizures: characteristics and associations

The characteristics of ictal electroencephalograms in 160 neonatal seizures of 43 babies were correlated with mortality and neurodevelopmental outcomes. Neonatal seizures are focal at onset, most frequently temporal, and often occur during sleep. Twenty-one percent of babies with seizures died, and 76% of survivors manifested neurodevelopmental impairment during 2-6-year follow-up. A low-amplitude ictal electroencephalogram discharge was associated with increased mortality, and a frequency of <2 Hz with increased morbidity. Status epilepticus, ictal fractions, multiple foci, and bihemispheric involvement did not influence outcomes. Of 160 seizures, 99 exhibited no associated clinical features (electrographic seizures). Neonatal seizures with clinical correlates (electroclinical seizures) exhibited a higher amplitude and frequency of ictal electroencephalogram discharge than electrographic seizures. During electroclinical seizures, the ictal electroencephalogram was more likely to involve larger areas of the brain and to cross the midline. Mortality and morbidity were similar in babies with electroclinical and electrographic seizures, emphasizing the need to diagnose and treat both types. Ictal electroencephalogram topography has implications for electrode application during limited-channel, amplitude-integrated electroencephalograms. We recommend temporal and paracentral electrodes. Video electroencephalograms are important in diagnosing neonatal seizures and providing useful information regarding ictal electroencephalogram characteristics.

Risk of later seizure after perinatal arterial ischemic stroke: a prospective cohort study

OBJECTIVE

Although acute seizures are common among neonates with arterial ischemic stroke (AIS), the incidence of subsequent seizures is unknown. The goals of this study were to determine the incidence of seizures following hospital discharge after perinatal acute AIS, and to assess lesion characteristics associated with later seizure occurrence.

METHODS

Neonates with confirmed acute AIS on MRI were identified through a prospective stroke registry. Clinic visits and telephone follow-up identified occurrence of seizures after hospital discharge. MRI scans were graded for size and characteristics of infarct, and associations with seizures after stroke were analyzed.

RESULTS

At a mean (SD) follow-up of 31.3 (16.1) months, 11 of 46 (23.9%) patients with perinatal AIS had at least 1 seizure. Five patients had a single episode of seizure, and 6 developed epilepsy. The Kaplan-Meier probability of remaining seizure-free at 3 years was 73%. Stroke size on MRI was significantly associated with development of later seizures, with an incidence rate of later seizures 6.2 times higher among those with larger stroke size.

CONCLUSIONS

Seizures occurred in <25% of patients during initial follow-up after perinatal AIS. Of those with seizures, nearly half had a single episode of seizure and not early epilepsy. Larger stroke size was associated with higher risk of seizure. These data suggest that prolonged treatment with anticonvulsant agents may not be indicated for seizure prophylaxis after perinatal AIS. These findings may help guide clinicians in counseling families and could form the basis for much-needed future research in this area.

Neurodevelopmental outcomes in neonates with seizures: a numerical score of background encephalography to help prognosticate

There is a high incidence of mortality and neurodevelopmental sequelae in babies with neonatal seizures. The electroencephalography (EEG) background has been shown to be an excellent predictor of outcome by most studies, with a few suggesting limited value in prognostication. Previous studies suggest poor prognosis with severely abnormal backgrounds, but prediction was difficult with moderate abnormalities. The proposed numerical scoring system for the EEG background provides an objective method of evaluation with improved reproducibility, categorization, and prognostication. Our study showed that the numerical score of EEG background was a good predictor of outcome. Higher numerical scores reflecting greater abnormality of background EEG were associated with increasing incidence of mortality, neurodevelopmental impairment, cerebral palsy, vision and hearing impairment, and epilepsy. The numerical score also correlated with neuroimaging abnormalities. A numerical EEG score can help target interventional strategies for neonatal seizures.

Early onset epilepsy and inherited metabolic disorders: diagnosis and management

Epileptic encephalopathies presenting in early life present a diagnostic and therapeutic challenge. These disorders present with multiple seizure types that are treatment resistant and associated with significant abnormalities on electroencephalographic studies. The underlying etiology in many cases may be related to an inborn error of metabolism. Efforts to establish the specific diagnosis of a genetic defect or an inborn error of metabolism often results in requests for a vast array of biochemical and molecular tests leading to an expensive workup. In this review, we present the clinician with information that provides a rationale for a selective and nuanced approach to biochemical assays, and initial treatment strategies while waiting for a specific diagnosis to be established. A careful consideration of the presentation, identification of potentially treatable conditions, and consultation with the biochemical genetics laboratory can lead to a greater measure of success while limiting cost overruns. Such a targeted approach is hoped will lead to an early diagnosis and appropriate interventions.

Use of amplitude integrated electroencephalography (aEEG) in patients with inborn errors of metabolism - a new tool for the metabolic geneticist

Patients with metabolic disorders often, especially as newborns, present with encephalopathy and seizures, frequently requiring intensive care during metabolic crises. Cerebral function monitoring using amplitude integrated electroencephalography (aEEG) can be utilized to supplement clinical assessment and other monitoring already in use in the intensive care setting. In this technique, a one or two-channel EEG tracing is obtained, processed, compressed and displayed. Use of aEEG is well established in evaluation and treatment of newborns with hypoxic ischemic encephalopathy. The basis of aEEG interpretation is the recognition of patterns which have been defined for different degrees of encephalopathy. Seizures are identified on the compressed tracing in combination with analysis of the corresponding raw EEG tracing. This review discusses the experience, although limited at this time, with use of aEEG in infants with inborn errors of metabolism. Through an international collaborative, the International Registry for Cerebral Function Monitoring in Patients with Genetics Disorders and Brain Malformations, aEEG tracings of patients with inborn errors of metabolism were collected. The features of 25 traces are included in this review. This collection includes patients with hyperammonemia (HA, n=4), disorders of energy metabolism (DEM, n=9), disorders of amino and organic acid metabolism (DAOAM, n=7), and peroxisomal disorders (PD, n=5). Fifteen of 25 patients demonstrated encephalopathic changes, including patients with HA, DEM and DAOAM, but not PD. In 15 of 25 patients seizure potentials were identified. In HA, DEM, and DAOAM both encephalopathy and seizures may coincide, while in peroxisomal disorders seizures were seen without background patterns indicating encephalopathy, likely due to neuronal migration defects as the underlying cause. The current experience with the use of aEEG in these patients, while limited, indicates that cerebral function monitoring techniques have a role in treatment of patients with metabolic disorders, especially during metabolic crises. Use of aEEG in this patient group is encouraged if locally available, and collaborative efforts to collect data on aEEG use in patients with metabolic disorders are encouraged to further define the scope and utility of this procedure.

Seizures are associated with brain injury severity in a neonatal model of hypoxia-ischemia

Hypoxia-ischemia is a significant cause of brain damage in the human newborn and can result in long-term neurodevelopmental disability. The loss of oxygen and glucose supply to the developing brain leads to excitotoxic neuronal cell damage and death; such over-excitation of nerve cells can also manifest as seizures. The newborn brain is highly susceptible to seizures although it is unclear what role they have in hypoxic-ischemic (H/I) injury. The aim of this study was to determine an association between seizures and severity of brain injury in a piglet model of perinatal H/I and, whether injury severity was related to type of seizure, i.e. sub-clinical (electrographic seizures only) or clinical (electrographic seizures+physical signs). Hypoxia (4% O(2)) was induced in anaesthetised newborn piglets for 30 min with a final 10 min period of hypotension; animals were recovered and survived to 72 h. Animals were monitored daily for seizures both visually and with electroencephalogram (EEG) recordings. Brain injury was assessed with magnetic resonance imaging (MRI), (1)H-MR spectroscopy ((1)H-MRS), EEG and by histology (haematoxylin and eosin). EEG seizures were observed in 75% of all H/I animals, 46% displayed clinical seizures and 29% sub-clinical seizures. Seizure animals showed significantly lower background amplitude EEG across all post-insult days. Presence of seizures was associated with lower cortical apparent diffusion coefficient (ADC) scores and changes in (1)H-MRS metabolite ratios at both 24 and 72 h post-insult. On post-mortem examination animals with seizures showed the greatest degree of neuropathological injury compared to animals without seizures. Furthermore, clinical seizure animals had significantly greater histological injury compared with sub-clinical seizure animals; this difference was not apparent on MRI or (1)H-MRS measures. In conclusion we report that both sub-clinical and clinical seizures are associated with increased severity of H/I injury in a term model of neonatal H/I.

Neonatal seizures: an update on mechanisms and management

The lifespan risk of seizures is highest in the neonatal period. Current therapies have limited efficacy. Although the treatment of neonatal seizures has not changed significantly in the last several decades, there has been substantial progress in understanding developmental mechanisms that influence seizure generation and responsiveness to anticonvulsants. This article provides an overview of current approaches to the diagnosis and treatment of neonatal seizures, and some of the recent insights about the pathophysiology of neonatal seizures that may provide the foundation for better treatment are identified.

Decreased seizure activity in a human neonate treated with bumetanide, an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1

Neonatal seizures have devastating consequences for brain development and are inadequately treated by available antiepileptics. In neonates, gamma-aminobutyric acid (GABA) is an excitatory neurotransmitter due to elevated levels of intraneuronal chloride achieved by robust activity of the Na(+)-K(+)-2Cl( -) cotransporter (NKCC1). This depolarizing action of GABA likely contributes to the lowered seizure threshold, increased seizure propensity, and poor efficacy of GABAergic anticonvulsants among infants. The diuretic bumetanide inhibits NKCC1 and silences seizure activity in rodent models of neonatal seizures, but its effect on seizures in human neonates is unknown. Continuous electroencephalography (EEG) monitoring was used to quantify the number, duration, and frequency of seizures 2 hours before and after the administration of bumetanide in a neonate with intractable multifocal seizures. Significant reductions in mean seizure duration and frequency were noted following treatment, with no associated clinical side effects or metabolic imbalances. These results suggest bumetanide may exert antiepileptic effects in human neonates.

Controversies in neonatal seizure management

Seizures in the newborn period are common and frequently indicate serious underlying brain injury. Although accumulating evidence suggests that they may impair brain development, there are currently no evidence-based guidelines for evaluation and management of neonatal seizures. In this review, we will address some of the current controversies facing child neurologists and neonatologists, including how to define, monitor, and treat neonatal seizures.

Treatment of the term newborn with brain injury: simplicity as the mother of invention

Neonatal brain injury remains a common cause of developmental disability, despite tremendously enhanced obstetrical and neonatal care. The timing of brain injury occurs throughout gestation, labor, and delivery, providing an evolving form of brain injury and a moving target for therapeutic intervention. Nonetheless, markedly improved methods are available to identify those infants injured at birth, via clinical presentation with neonatal encephalopathy and neuroimaging techniques. Postischemic hypothermia has been shown to be of tremendous clinical promise in several completed and ongoing trials. As part of this approach to the treatment of the newborn, other parameters of physiologic homeostasis can and should be attended to, with strong animal and clinical evidence that their correction will have dramatic influence on the outcome of the newborn infant. This review addresses aspects of newborn care to which we can direct our attention currently, and which should result in a safe and efficacious improvement in the prognosis of the newborn with neonatal encephalopathy.

Factors associated with adverse neurodevelopmental outcomes in infants with congenital heart disease

OBJECTIVE

To review reported neurodevelopmental outcome data for patients with congenital heart disease, identify risk factors for adverse neurodevelopmental sequelae and summarize potential neuromonitoring strategies that have been described.

METHODS

A Medline search was performed utilizing combinations of the keywords congenital heart, cardiac, neurologic, neurodevelopment, neuromonitoring, quality of life, and outcome. All prospective and longitudinal follow-up studies of patients with congenital heart disease were included. Additionally, studies that examined neuroimaging, neuromonitoring, and clinical factors in relation to outcome were examined. Case reports and editorials were excluded. Additional references were retrieved from selected articles if the abstract described an evaluation of neurodevelopmental outcomes and/or predictors of outcome in patients with congenital heart disease.

RESULTS

Overall, patients with CHD have increased rates of neurodevelopmental impairments, although intelligence appears to be in the normal range. Preoperative risk stratification, intraoperative techniques, postoperative care, and neuromonitoring strategies may all contribute to ultimate long-term neurodevelopmental outcomes in patients with CHD postsurgical repair.

CONCLUSIONS

As advances in the medical and surgical management improves survival in patients with CHD, increasing knowledge about neurodevelopmental outcomes and the factors that affect them will provide for strategies to optimize long-term outcome in this high-risk population.

Seizure detection in neonates: Improved classification through supervised adaptation

The goal of neonatal seizure detection is the development of a patient independent system to alert staff in the neonatal intensive care unit of ongoing seizures. This study demonstrates the potential in adapting a patient independent classifier using patient specific data. Supervised adaptation is investigated using the basic gradient descent algorithm and least mean squares procedures. An increase in mean ROC area of 3% is obtained for the best performing learning algorithm, yielding an increase in mean accuracy of 7.7% compared to the patient independent algorithm.