Outcome of electroclinical, electrographic, and clinical seizures in the newborn infant

Neonatal seizures: stepping outside the comfort zone

Seizures are the most common neurological disorders in newborns. Managing neonatal seizures is challenging, especially for neurologists who are not neonatal specialists. Acute brain injury during ischemic insult is a key component of seizure occurrence, while genetic and metabolic disorders play less prevalent but more severe roles. The diagnosis of neonatal seizure is ambiguous, as the subjective differentiation between seizure and nonepileptic events is difficult; therefore, electrographic recording is the gold standard for diagnosis. The detection of electrographic seizures by neonatologists is currently facilitated by amplitude-integrated electroencephalography availability in many neonatal intensive care units. Although it is less sensitive than conventional electroencephalography, it is better to record all risky neonates to filter the abnormal events as early as possible to enable the initiation of dedicated therapy at proper dose and time and facilitate the initial response to antiepileptic drugs. This, in turn, helps maintain the balance between unnecessary drug use and their neurotoxic effects. Moreover, the early treatment of electrographic seizures plays a vital role in the suppression of subsequent abnormal brain electricity (status epilepticus) and shortening the hospital stay. An explicit understanding of seizure etiology and pathophysiology should direct attention to the proper prescription of short- and long-term antiepileptic medications to solve the challenging issue of whether neonatal seizures progress to postneonatal epilepsy and long-term cognitive deficits. This review addresses recent updates in different aspects of neonatal seizures, particularly electrographic discharge, including their definition, etiology, classification, diagnosis, management, and neurodevelopmental outcomes.

Optical Monitoring in Neonatal Seizures

BACKGROUND

Neonatal seizures remain a significant cause of morbidity and mortality worldwide. The past decade has resulted in substantial progress in seizure detection and understanding the impact seizures have on the developing brain. Optical monitoring such as cerebral near-infrared spectroscopy (NIRS) and broadband NIRS can provide non-invasive continuous real-time monitoring of the changes in brain metabolism and haemodynamics.

AIM

To perform a systematic review of optical biomarkers to identify changes in cerebral haemodynamics and metabolism during the pre-ictal, ictal, and post-ictal phases of neonatal seizures.

METHOD

A systematic search was performed in eight databases. The search combined the three broad categories: (neonates) AND (NIRS) AND (seizures) using the stepwise approach following PRISMA guidance.

RESULTS

Fifteen papers described the haemodynamic and/or metabolic changes observed with NIRS during neonatal seizures. No randomised controlled trials were identified during the search. Studies reported various changes occurring in the pre-ictal, ictal, and post-ictal phases of seizures.

CONCLUSION

Clear changes in cerebral haemodynamics and metabolism were noted during the pre-ictal, ictal, and post-ictal phases of seizures in neonates. Further studies are necessary to determine whether NIRS-based methods can be used at the cot-side to provide clear pathophysiological data in real-time during neonatal seizures.

Diagnosis and Management of Seizures in the Preterm Infant

The risk of seizure is increased in premature neonates compared to full term infants, with a distinct profile of etiologies, timing and character. Despite improvements in neonatal care, preterm infants with seizure continue to have higher risk of abnormal neurodevelopmental outcomes when compared to preterm infants without seizures, or to full term infants with seizures. Very limited evidence guides the care of this challenging population, therefore, management of the preterm neonate with seizure is largely extrapolated from the care of full-term neonates. A critical need exists for well-designed clinical trials investigating and validating the safety, efficacy, and outcomes of seizure management in this vulnerable population.

Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus

Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABA_A receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.

Treating the symptom or treating the disease in neonatal seizures: a systematic review of the literature

Aim

The existing treatment options for neonatal seizures have expanded over the last few decades, but no consensus has been reached regarding the optimal therapeutic protocols. We systematically reviewed the available literature examining neonatal seizure treatments to clarify which drugs are the most effective for the treatment of specific neurologic disorders in newborns.

Method

We reviewed all available, published, literature, identified using PubMed (published between August 1949 and November 2020), that focused on the pharmacological treatment of electroencephalogram (EEG)-confirmed neonatal seizures.

Results

Our search identified 427 articles, of which 67 were included in this review. Current knowledge allowed us to highlight the good clinical and electrographic responses of genetic early-onset epilepsies to sodium channel blockers and the overall good response to levetiracetam, whose administration has also been demonstrated to be safe in both full-term and preterm newborns.

Interpretation

Our work contributes by confirming the limited availability of evidence that can be used to guide the use of anticonvulsants to treat newborns in clinical practice and examining the efficacy and potentially harmful side effects of currently available drugs when used to treat the developing newborn brain; therefore, our work might also serve as a clinical reference for future studies.

Outcome in preterm infants with seizures

Most neonatal seizures in preterm newborns are of acute symptomatic origin with a prevalence higher than in full-term infants. To date, recommendations for management of seizures in preterm newborns are scarce and do not differ from those in full-term newborns. Mortality in preterm newborns with seizures has significantly declined over the last decades, from figures of 84%-94% in the 1970s and 1980s to 22%-45% in the last years. However, mortality is significantly higher in those with a birth weight<1000g and a gestational age<28 weeks. Seizures are a strong predictor of unfavorable outcomes, including not only cerebral palsy, epilepsy, and intellectual disability, but also vision, hearing impairment, and microcephaly. The majority of patients with developmental delay are severely affected and this is usually associated with cerebral palsy. Furthermore, the incidence of epilepsy after neonatal seizures seems to be lower in preterm than in full-term infants but the risk is approximately 40 times greater than in the general population. Clinical studies cannot disentangle the specific and independent contributions of seizure-induced functional changes and the role of etiology and brain damage severity in determining the long-term outcomes in these newborns.

Diagnosis of seizures and encephalopathy using conventional EEG and amplitude integrated EEG

Seizures are more common in the neonatal period than at any other time of life, partly due to the relative hyperexcitability of the neonatal brain. Brain monitoring of sick neonates in the NICU using either conventional electroencephalography or amplitude integrated EEG is essential to accurately detect seizures. Treatment of seizures is important, as evidence increasingly indicates that seizures damage the brain in addition to that caused by the underlying etiology. Prompt treatment has been shown to reduce seizure burden with the potential to ameliorate seizure-mediated damage. Neonatal encephalopathy most commonly caused by a hypoxia-ischemia results in an alteration of mental status and problems such as seizures, hypotonia, apnea, and feeding difficulties. Confirmation of encephalopathy with EEG monitoring can act as an important adjunct to other investigations and the clinical examination, particularly when considering treatment strategies such as therapeutic hypothermia. Brain monitoring also provides useful early prognostic indicators to clinicians. Recent use of machine learning in algorithms to continuously monitor the neonatal EEG, detect seizures, and grade encephalopathy offers the exciting prospect of real-time decision support in the NICU in the very near future.

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.

Epilepsy after neonatal seizures: literature review

INTRODUCTION

Acute neonatal seizures are the most frequent neurological complication in the neonatal intensive care units and the seizing newborns have an increased risk of long-term morbidity. However, the relationship between neonatal seizures and the development of epilepsy later in life is still unclear.

METHODS

We performed a literature review using the search terms "neonatal seizures AND outcome", "neonatal seizures AND epilepsy", "neonatal seizures AND post-neonatal epilepsy", including secondary sources of data such as reference lists of articles reviewed. From the studies in which data were available, the incidence of epilepsy was calculated by dividing the number of all subjects who developed epilepsy in the different studies considered with the number of all newborns enrolled to the studies less the number of patients lost at follow-up.

RESULTS

We found 44 studies published between 1954 and 2013, of which 4 were population-based studies and the remaining were hospital-based case series. The overall population evaluated was 4538 newborns and 17.9% developed post-neonatal epilepsy, with an onset within the first year of life in 68.5% of the patients. In 80.7%, epilepsy was associated with other neurological impairments.

CONCLUSION

Estimates on epilepsy after neonatal seizures vary widely depending on selection criteria and length of the follow-up. However, it represents a common outcome of these newborns, especially in those with severe brain injury and additional neurodevelopmental disabilities.

Electrographic seizures are associated with brain injury in newborns undergoing therapeutic hypothermia

OBJECTIVE

Seizures are common among newborns with hypoxic-ischaemic encephalopathy (HIE) but the relationship between seizure burden and severity of brain injury among neonates receiving therapeutic hypothermia (TH) for HIE is unclear. We tested the hypothesis that seizure burden is associated with cerebral tissue injury independent of amplitude-integrated EEG (aEEG) background activity.

STUDY DESIGN

Term neonates undergoing 72 h of TH at four centres were selected for study if they had continuous aEEG and MRI. The aEEG with corresponding 2-channel raw EEG (aEEG/EEG), was classified by severity of background and seizure burden; MR images were classified by the severity of tissue injury.

RESULTS

Of 85 neonates, 52% had seizures on aEEG/EEG. Overall, 35% had high seizure burden, 49% had abnormal aEEG background in the first 24 h and 36% had severe injury on MRI. Seizures were most common on the first day, with significant recurrence during and after rewarming. Factors associated with severe injury on MRI were high seizure burden, poor aEEG background, 10 min Apgar and the need for more than one anticonvulsant. In multivariate logistic regression, high seizure burden was independently associated with greater injury on MRI (OR 5.00, 95% CI 1.47 to 17.05 p=0.01). Neither aEEG background, nor 10 min Apgar score were significant.

CONCLUSIONS

Electrographic seizure burden is associated with severity of brain injury on MRI in newborns with HIE undergoing TH, independent of degree of abnormality on aEEG background. Seizures are common during cooling, particularly on day 1, with a significant rebound on day 4.

Risk factors and scoring system as a prognostic tool for epilepsy after neonatal seizures

BACKGROUND

Neonatal seizures may cause irreversible changes to the immature brain and. A scoring system for early prognostic information could be a useful clinical tool. The aim of the study was to analyze risk factors for epilepsy after neonatal seizures, to validate Garfinkle's scoring system, and to analyze whether a new scoring system is feasible.

METHODS

A retrospective study of 176 newborns (59.1% boys, 40.9% girls, 70.5% term, 29.5% preterm; mean birth weight 2820 g), admitted to the Department of Neonatology, Division of Pediatrics, University Medical Centre, Ljubljana, because of neonatal seizures (clinical and/or neurophysiological), was performed. Epilepsy rate between 2 and 12 years of follow-up was 18.1%. Five independent predictors from Garfinkle's study and other known predictors were entered into hierarchical binary logistic regression models and analyzed through four steps to identify independent predictors of epilepsy. We tested whether any of the predictors was an effect modifier.

RESULTS

Of five potential predictors from Garfinkle's score, electroencephalograph background findings and etiology were predictive. Etiologies, gestation, mode of delivery, duration of seizures, and other risk factors at birth were found to be independent predictors. Duration of seizures has a different effect on prognosis depending on the gestational age.

CONCLUSION

Gestational age determines the association between duration of seizures and epilepsy. Scoring systems to predict development of epilepsy after neonatal seizures need to limit interaction between important predictor variables.

Impact of amplitude-integrated electroencephalograms on clinical care for neonates with seizures

Amplitude-integrated electroencephalography (aEEG) was recently introduced into neonatal intensive care in the United States. We evaluated whether aEEG has changed clinical care for neonates with seizures. This study included all 202 neonates treated for seizures at our hospital from 2002-2007. Neonates monitored with aEEG (n = 67) were compared with contemporary control neonates who were not monitored, despite the availability of aEEG (n = 57), and a historic control group of neonates treated for seizures before our neonatal intensive care unit initiated aEEG (n = 78). Eighty-two percent of those receiving phenobarbital (137/167) continued treatment after discharge, with no difference among groups. Adjusted for gestational age and length of stay, no difference among groups was evident in number of neuroimaging studies or number of antiepileptic drugs per patient. Fewer patients undergoing aEEG, compared with contemporary (16/67 vs 29/57, respectively, P = 0.001) or historic (n = 38/78, P = 0.002) controls, were diagnosed clinically with seizures without electrographic confirmation. We conclude that aEEG did not increase neuroimaging tests, and did not alter antiepileptic drug use. However, diagnostic precision regarding neonatal seizures improved with aEEG because fewer neonates were treated for seizures based solely on clinical findings, without electrographic confirmation.

Seizures and magnetic resonance imaging-detected brain injury in newborns cooled for hypoxic-ischemic encephalopathy

OBJECTIVE

To describe the association between electrographically detected seizures and brain injury evaluated by magnetic resonance imaging in newborns treated with hypothermia.

STUDY DESIGN

A total of 56 newborns treated with hypothermia were monitored using video electroencephalography through cooling and rewarming, and then imaged at a median of 5 days. The electroencephalograms were reviewed for indications of seizure and status epilepticus. Moderate-severe injury detected on magnetic resonance imaging was measured using a classification scheme similar to one predicting abnormal outcome in an analogous population.

RESULTS

Seizures were recorded in 17 newborns (30%), 5 with status epilepticus. Moderate-severe injury was more common in newborns with seizures (relative risk, 2.9; 95% CI, 1.2-4.5; P=.02), and was present in all 5 newborns with status epilepticus. Newborns with moderate-severe injury had seizures that were multifocal and of later onset, and they were more likely to experience recurrent seizures after treatment with 20 mg/kg phenobarbital. Newborns with only subclinical seizures were as likely to have injury as those with seizures with a clinical correlate (57% vs 60%).

CONCLUSION

Seizures represent a risk factor for brain injury in the setting of therapeutic hypothermia, especially in neonates with status epilepticus, multifocal-onset seizures, and a need for multiple medications. However, 40% of our neonates were spared from brain injury, suggesting that the outcome after seizures is not uniformly poor in children treated with therapeutic hypothermia.

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.

The relationship of neonatal subclinical electrographic seizures to neurodevelopmental outcome at 1 year of age

OBJECTIVE

To evaluate the influence of 'only electroencephalographic (EEG)' and 'EEG plus clinical' seizures during neonatal period on neurodevelopment of the infants.

PATIENTS AND METHODS

The long-term digital-video- EEG tracings of the first 3 days of life of 30 neonates were assessed. The babies were subdivided into three groups: Group 1 had neither EEG nor clinical seizures. Group 2 had EEG seizures but no clinical seizures. Group 3 experienced both EEG and clinical seizures. The groups were compared in regard to psychomotor retardation and epilepsy at corrected age of 1 year.

RESULTS

The mean birthweight was 1952.50 +/- 978.74 (685-4103) g. The mean gestational age was 32.53 +/- 4.26 (24-40) weeks. In regard to sex, gestational age and birth weight, there was no significant difference between the three groups. Ten percent of newborns in Group 1 and 53.8% of newborns in Group 3 had psychomotor retardation. No babies in Group 2 experienced psychomotor retardation. The differences between the Groups 1 and 3 and Groups 2 and 3 were found statistically significant. Only one baby in Group 3 had epilepsy. In Groups 1 and 2, no babies had epilepsy. The differences between the groups were not significant.

CONCLUSION

Neonatal seizures, but not silent EEG seizures are in relationship with poor neurodevelopmental outcome evaluated at corrected age of 1 year in newborns.

Differences in cortical versus subcortical GABAergic signaling: a candidate mechanism of electroclinical uncoupling of neonatal seizures

Electroclinical uncoupling of neonatal seizures refers to electrographic seizure activity that is not clinically manifest. Uncoupling increases after treatment with Phenobarbital, which enhances the GABA(A) receptor (GABA(A)R) conductance. The effects of GABA(A)R activation depend on the intracellular Cl(-) concentration ([Cl(-)](i)) that is determined by the inward Cl(-) transporter NKCC1 and the outward Cl(-) transporter KCC2. Differential maturation of Cl(-) transport observed in cortical versus subcortical regions should alter the efficacy of GABA-mediated inhibition. In perinatal rat pups, most thalamic neurons maintained low [Cl(-)](i) and were inhibited by GABA. Phenobarbital suppressed thalamic seizure activity. Most neocortical neurons maintained higher [Cl(-)](i), and were excited by GABA(A)R activation. Phenobarbital had insignificant anticonvulsant responses in the neocortex until NKCC1 was blocked. Regional differences in the ontogeny of Cl(-) transport may thus explain why seizure activity in the cortex is not suppressed by anticonvulsants that block the transmission of seizure activity through subcortical networks.

Neonatal seizures: do they damage the brain?

Seizures are an early sign of brain injury in newborns. These seizures are in most cases repetitive or associated with asymptomatic electrographic seizures. Despite the relative resistance of the immature brain to seizure-induced brain damage, there is more and more evidence that neonatal seizures impair normal brain development. This review addresses the changes associated with neonatal seizures and discusses current and future potential neuroprotective strategies.

Characterisation of heart rate changes and their correlation with EEG during neonatal seizures

The effect of seizures on instantaneous HR (iHR) in 12 neonates is investigated here. HR can be readily extracted from the ECG and can be employed as an additional signal in seizure detection algorithms. The change in instantaneous HR and its correlation with the change in RMS EEG amplitude were examined. Two methods were employed to classify significant iHR changes. Significant correlation (p 0.05) during seizure was observed in 100% of patients (83.33% of seizures). Overall, significant iHR changes (classified by either method) were found in 83% of patients (50% of seizures). It was found that a markedly higher iHR was observed in patients whose seizures were not classified as having significant iHR changes.

Cerebral monitoring of the term infant

Continuously monitoring brain ftinction at the bedside in the NICU for term infants at risk of brain injury has become part of routine clinical practice in many countries. These monitors offer invaluable information about the sick infant's neurologic status by providing real-time measurements of the brain's electrical activity and identifring or confirming seizure activity. With the increasing availability of bedside electroencephalogram technology, it is essential for neonatal intensive care nursing staff to understand the rationale for its use, as well as the fundamentals of application and interpretation of this new technology.

Neonatal seizures: dilemmas in workup and management

There is a pressing need for consistent, evidence-based guidelines in the management of neonatal seizures by pediatric neurologists and neonatologists. Israeli pediatric neurologists and neonatologists completed a 20-item, self-administered questionnaire on choices of antiepileptic drugs, treatment of intractable neonatal seizures (unremitting seizures after 3 medications), treatment duration, and recommended workup. The responding 36/55 (65%) neurologists and 66/112 (59%) neonatologists made similar antiepileptic drug choices (phenobarbital as first line, phenytoin as second line, and benzodiazepines as third line). Antiepileptic treatment duration was similar for both groups, but varied considerably within them (range, 1-52 weeks). Neurologists tended to recommend longer treatment for seizures secondary to asphyxia or hemorrhage. Neurologists and neonatologists recommended different antiepileptic drugs for intractable neonatal seizures: valproic acid and topiramate by neurologists, vs lidocaine and benzodiazepines by neonatologists (P = 0.0023). Fewer neurologists recommended continuous electroencephalography monitoring after asphyxia than neonatologists (40% vs 70.5%, P = 0.013). These responses reflect both similarities and inconsistencies of the two groups in diagnosing and treating neonatal seizures. Our findings call for controlled clinical trials to establish protocols for (1) diagnosing neonatal seizures, (2) studying the efficacy and safety of new-generation antiepileptic drugs, and (3) determining optimal duration of drug administration.

Prediction of seizures in asphyxiated neonates: correlation with continuous video-electroencephalographic monitoring

BACKGROUND

After perinatal asphyxia, predicting which infants will develop significant hypoxic-ischemic encephalopathy and neonatal seizures remains a difficult task. High-risk markers (Apgar score, acidosis, nucleated red blood cells, and resuscitation) have been used to predict neonatal seizures with varying success. The "3 strikes" of Apgar score of <5 at 5 minutes, pH <7.00, and need for intubation have been cited as having a positive predictive value of 80%. We examined whether the predictive values of these markers would be increased if early continuous electroencephalographic monitoring allowed us to accurately identify all neonatal seizures and to grade the encephalopathy.

METHOD

We recruited term infants with perinatal asphyxia. Continuous video electroencephalography was commenced soon after birth and continued for 24 to 72 hours. The abilities of high-risk markers to predict electroencephalographic seizures, background electroencephalographic activity, and Sarnat grade were examined.

RESULTS

Forty-nine infants were suitable for analysis. Electrographic seizures occurred in 11 of the 49 infants. Encephalopathy was scored by using Sarnat grade (6, severe; 18, moderate; 25, mild) and electroencephalographic findings (4 inactive, 4 major abnormalities, 16 moderate abnormalities, and 25 normal/mildly abnormal). Apgar score of <5 at 5 minutes, pH <7.0, and the need for intubation had positive predictive values for neonatal seizures of 18%, 16%, and 21%, respectively. Combining these markers gave a positive predictive value of 25% and a negative predictive value of 77%. Substituting base deficit or lactate for pH in the 3-strikes model did not improve its predictive value. Apgar score of <5 at 5 minutes, nucleated red blood cells, and a base deficit less than -15 mEq/L showed some association with Sarnat grade. Only 5-minute Apgar score was significantly associated with both Sarnat grade and electroencephalographic grade.

CONCLUSION

After perinatal asphyxia, neither the condition at birth nor the degree of metabolic acidosis reliably predict neonatal seizures.

Early continuous video-EEG in acute near-total intrauterine asphyxia

The evolution of electroencephalographic changes after acute hypoxic-ischemic injury is poorly understood, as a clear time of insult is often absent and continuous electroencephalographic monitoring in the first 3 days after such injury has not been previously reported. Infants who suffer sudden profound asphyxia, often termed "acute near-total intrauterine asphyxia", have evidence of damage to the deep gray matter. In these infants it is possible to time the onset and duration of cerebral ischemia. This report describes early continuous video-electroencephalography from 3 hours after birth in an infant with the characteristic clinical and radiologic features of acute near-total intrauterine asphyxia.

Epileptic seizures, epilepsy and epileptic syndromes in newborns: A nosological approach to 94 new cases by the 2001 proposed diagnostic scheme for people with epileptic seizures and with epilepsy

PURPOSE

To assess the advantages of the 2001 ILAE proposed diagnostic scheme for classification of newborns with epileptic seizures over the 1989 ILAE classification.

METHOD

Clinical features, seizure semiology and duration, neurological evaluation, ictal and interictal EEG, brain imaging and outcome at the end of the neonatal period (44 weeks post-conceptional age) of 94 newborns with EEG confirmed seizures were analyzed. The 2001 ILAE classification was applied where possible.

RESULTS

Twenty patients died before the end of the neonatal period. In the remaining patients, applying axis 3, we classified 54 newborns as having epileptic seizures that do not require a diagnosis of epilepsy; 14 as symptomatic partial epilepsy; 5 within the neonatal epileptic syndromes and one as benign neonatal seizures (NS). Axis 4 in all newborns provided a valuable tool in order to better define the individual patient.

CONCLUSIONS

Compared to the 1989 ILAE classification, which allowed a syndromic diagnosis in only 6/94 patients, the remaining being classified as Epilepsies and Syndromes undetermined whether focal or generalized, the 2001 ILAE diagnostic scheme, applied at the end of the neonatal period, offers a variety of approaches to classification, allowing an early distinction between epilepsy and single or isolated clusters of seizures, with therapeutic and prognostic implications.

The relationship between the onset of electrographic seizure activity after birth and the time of cerebral injury in utero

In the fetal lamb model of hypoxic-ischaemic injury, the insult is followed by EEG depression, after which seizures emerge at 7-13 hours. We explored the relationship between the emergence of electrographic seizures and our estimate of the time of the cerebral injury in nine babies who underwent continuous video-EEG monitoring from soon after birth. Babies with prelabour insults had their first seizures before 12 hours of age, whereas those whose insult was peripartum had seizure onset at 18-20 hours of age. EEG seizure onset time could have important clinical and medico-legal applications, and be related to the time or severity of the insult, or both.

Recovery of amplitude integrated electroencephalographic background patterns within 24 hours of perinatal asphyxia

OBJECTIVE

To assess the time course of recovery of severely abnormal initial amplitude integrated electroencephalographic (aEEG) patterns (flat trace (FT), continuous low voltage (CLV), or burst suppression (BS)) in full term asphyxiated neonates, in relation to other neurophysiological and neuroimaging findings and neurodevelopmental outcome.

METHODS

A total of 190 aEEGs of full term infants were reviewed. The neonates were admitted within 6 hours of birth to the neonatal intensive care unit because of perinatal asphyxia, and aEEG recording was started immediately. In all, 160 infants were included; 65 of these had an initial FT or CLV pattern and 25 an initial BS pattern. Neurodevelopmental outcome was assessed using a full neurological examination and the Griffiths' mental developmental scale.

RESULTS

In the FT/CLV group, the background pattern recovered to continuous normal voltage within 24 hours in six of the 65 infants (9%). All six infants survived the neonatal period; one had a severe disability, and five were normal at follow up. In the BS group, the background pattern improved to normal voltage in 12 of the 25 infants (48%) within 24 hours. Of these infants, one died, five survived with moderate to severe disability, two with mild disability, and four were normal. The patients who did not recover within 24 hours either died in the neonatal period or survived with a severe disability.

CONCLUSION

In this study there was a small group of infants who presented with a severely abnormal aEEG background pattern within six hours of birth, but who achieved recovery to a continuous normal background pattern within the first 24 hours. Sixty one percent of these infants survived without, or with a mild, disability.

Postneonatal epilepsy following amplitude-integrated EEG-detected neonatal seizures

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

Non-expert use of the cerebral function monitor for neonatal seizure detection

BACKGROUND

The cerebral function monitor (CFM) is widely used to detect neonatal seizures, but there are very few studies comparing it with simultaneous electroencephalography (EEG).

OBJECTIVE

To determine the accuracy of non-expert use of the CFM and to assess interobserver agreement of CFM seizure detection.

PATIENTS

Babies admitted to the neonatal intensive care unit at King's College Hospital who were at high risk of seizure and had video-EEG monitoring.

METHODS

Video-EEG was used to detect seizures. Each baby had CFM recordings at speeds of 6, 15, and 30 cm/h during the EEG. Four neonatologists, trained in CFM seizure recognition, independently rated one hour CFM samples at three speeds from each baby. Interobserver agreement was quantified using Cohen's kappa.

RESULTS

CFM traces from 19 babies with EEG seizures and 21 babies without EEG seizures were analysed. Overall non-expert interpretation of the CFM performed poorly as a seizure detector compared with simultaneous EEG (sensitivities 38% at 6 cm/h; 54% at 15 cm/h; 55% at 30 cm/h). Although babies with seizures were more likely to be correctly classified at higher speeds (p = 0.02), babies without seizures were also more likely to be misclassified (p < 0.001). Agreement between observers was not good at any speed (kappa values from 0.01 to 0.39). The observers usually detected generalised seizures but often missed seizures that were focal, low amplitude, or lasted less than one minute.

CONCLUSION

Approximately half of all neonatal seizures may be missed using CFM alone. Neonatal seizures need to be diagnosed, characterised, and quantified first using EEG. The CFM may then be useful for long term monitoring.

Phenobarbitone, neonatal seizures, and video-EEG

AIMS

To evaluate the effectiveness of phenobarbitone as an anticonvulsant in neonates.

METHODS

An observational study using video-EEG telemetry. Video-EEG was obtained before treatment was started, for an hour after treatment was given, two hours after treatment was given, and again between 12 and 24 hours after treatment was given. Patients were recruited from all babies who required phenobarbitone (20-40 mg/kg intravenously over 20 minutes) for suspected clinical seizures and had EEG monitoring one hour before and up to 24 hours after the initial dose. An EEG seizure discharge was defined as a sudden repetitive stereotyped discharge lasting for at least 10 seconds. Neonatal status epilepticus was defined as continuous seizure activity for at least 30 minutes. Seizures were categorised as EEG seizure discharges only (electrographic), or as EEG seizure discharges with accompanying clinical manifestations (electroclinical). Surviving babies were assessed at one year using the Griffiths neurodevelopmental score.

RESULTS

Fourteen babies were studied. Four responded to phenobarbitone; these had normal or moderately abnormal EEG background abnormalities and outcome was good. In the other 10 babies electrographic seizures increased after treatment, whereas electroclinical seizures reduced. Three babies were treated with second line anticonvulsants, of whom two responded. One of these had a normal neurodevelopmental score at one year, but the outcome for the remainder of the whole group was poor.

CONCLUSION

Phenobarbitone is often ineffective as a first line anticonvulsant in neonates with seizures in whom the background EEG is significantly abnormal.

Winner of the young physician's section of the Gowers' prize 2000. Too good to be true? Thomas Willis--neonatal convulsions, childhood stroke and infanticide in seventeenth century England

A case of neonatal convulsion reported by Thomas Willis (1621-1675) together with its post mortem findings is quoted as being congenital intracerebral haemorrhage or strongly suggested as being the earliest pathological description of childhood cerebrovascular disease. However these authors only reviewed the incomplete written record left by Willis, describing how this case was the fourth consecutive child that the mother had lost to neonatal convulsions. The medical record is completed by notes taken by John Locke from a lecture delivered by Willis 3 or 4 years before the case was first published. Here, Locke relates how the mother subsequently had three further children who were all treated by Willis soon after birth and all survived uneventfully. Reviewing the post mortem findings and the full case histories modern medical science gives a different interpretation. Instead, I suggest that the case history given and pathological features described are more in keeping with a whiplash shaking injury than with cerebrovascular disease or a stroke. I believe that this is the earliest pathological description of shaking injury in childhood. We can never know why Willis did not publish the full success of his management of the subsequent children but it may have been due to his dramatic experience of a similar mother early on in his medical career.