The long-term effects of neonatal seizures

An Opportunity to Fill a Gap for Newborn Screening of Neurodevelopmental Disorders

Screening newborns using genome sequencing is being explored due to its potential to expand the list of conditions that can be screened. Previously, we proposed the need for large-scale pilot studies to assess the feasibility of screening highly penetrant genetic neurodevelopmental disorders. Here, we discuss the initial experience from the GUARDIAN study and the systemic gaps in clinical services that were identified in the early stages of the pilot study.

Dysfunctional hippocampal-prefrontal network underlies a multidimensional neuropsychiatric phenotype following early-life seizure

Brain disturbances during development can have a lasting impact on neural function and behavior. Seizures during this critical period are linked to significant long-term consequences such as neurodevelopmental disorders, cognitive impairments, and psychiatric symptoms, resulting in a complex spectrum of multimorbidity. The hippocampus-prefrontal cortex (HPC-PFC) circuit emerges as a potential common link between such disorders. However, the mechanisms underlying these outcomes and how they relate to specific behavioral alterations are unclear. We hypothesized that specific dysfunctions of hippocampal-cortical communication due to early-life seizure would be associated with distinct behavioral alterations observed in adulthood. Here, we performed a multilevel study to investigate behavioral, electrophysiological, histopathological, and neurochemical long-term consequences of early-life Status epilepticus in male rats. We show that adult animals submitted to early-life seizure (ELS) present working memory impairments and sensorimotor disturbances, such as hyperlocomotion, poor sensorimotor gating, and sensitivity to psychostimulants despite not exhibiting neuronal loss. Surprisingly, cognitive deficits were linked to an aberrant increase in the HPC-PFC long-term potentiation (LTP) in a U-shaped manner, while sensorimotor alterations were associated with heightened neuroinflammation, as verified by glial fibrillary acidic protein (GFAP) expression, and altered dopamine neurotransmission. Furthermore, ELS rats displayed impaired HPC-PFC theta-gamma coordination and an abnormal brain state during active behavior resembling rapid eye movement (REM) sleep oscillatory dynamics. Our results point to impaired HPC-PFC functional connectivity as a possible pathophysiological mechanism by which ELS can cause cognitive deficits and psychiatric-like manifestations even without neuronal loss, bearing translational implications for understanding the spectrum of multidimensional developmental disorders linked to early-life seizures.

Seizure Burden and Neurologic Outcomes After Neonatal Encephalopathy

BACKGROUND AND OBJECTIVES

Seizures are common during neonatal encephalopathy (NE), but the contribution of seizure burden (SB) to outcomes remains controversial. This study aims to examine the relationship between electrographic SB and neurologic outcomes after NE.

METHODS

This prospective cohort study recruited newborns ≥36 weeks postmenstrual age around 6 hours of life between August 2014 and November 2019 from a neonatal intensive care unit (NICU). Participants underwent continuous electroencephalography for at least 48 hours, brain MRI within 3-5 days of life, and structured follow-up at 18 months. Electrographic seizures were identified by board-certified neurophysiologists and quantified as total SB and maximum hourly SB. A medication exposure score was calculated based on all antiseizure medications given during NICU admission. Brain MRI injury severity was classified based on basal ganglia and watershed scores. Developmental outcomes were measured using the Bayley Scales of Infant Development, Third Edition. Multivariable regression analyses were performed, adjusting for significant potential confounders.

RESULTS

Of 108 enrolled infants, 98 had continuous EEG (cEEG) and MRI data collected, of which 5 were lost to follow-up, and 6 died before age 18 months. All infants with moderate-severe encephalopathy completed therapeutic hypothermia. cEEG-confirmed neonatal seizures occurred in 21 (24%) newborns, with a total SB mean of 12.5 ± 36.4 minutes and a maximum hourly SB mean of 4 ± 10 min/h. After adjusting for MRI brain injury severity and medication exposure, total SB was significantly associated with lower cognitive (-0.21, 95% CI -0.33 to -0.08, p = 0.002) and language (-0.25, 95% CI -0.39 to -0.11, p = 0.001) scores at 18 months. Total SB of 60 minutes was associated with 15-point decline in language scores and 70 minutes for cognitive scores. However, SB was not significantly associated with epilepsy, neuromotor score, or cerebral palsy (p > 0.1).

DISCUSSION

Higher SB during NE was independently associated with worse cognitive and language scores at 18 months, even after adjusting for exposure to antiseizure medications and severity of brain injury. These observations support the hypothesis that neonatal seizures occurring during NE independently contribute to long-term outcomes.

The Role of Amplitude-Integrated Electroencephalography (aEEG) in Monitoring Infants with Neonatal Seizures and Predicting Their Neurodevelopmental Outcome

Newborn monitoring in neonatal intensive care units (NICU) is mandatory, but neurological and especially electroencephalographic (EEG) monitoring can be overlooked or delayed until the newborn is clinically stable. However, the neonatal period is associated with the highest risk of seizures in humans, and the clinical symptoms may often be discrete, but the evolution and long-term neurodevelopmental disorders in these patients may be important. In response to this issue, we conducted a study to evaluate newborns who experienced neonatal seizures (NS) in the NICU and monitored their long-term neurological development. We enrolled 73 term and preterm newborns who underwent EEG monitoring using amplitude-integrated electroencephalography (aEEG). We then followed their neurological development until around 18 months of age, with 59 patients remaining in the long-term study. A total of 22% of patients with NS developed epilepsy, 12% cerebral palsy, 19% severe neurodevelopmental disabilities, and 8.5% died within the first 18 months of life. Our findings indicate that aEEG background pattern is a strong predictor of unfavorable neurological outcomes, with an odds ratio of 20.4174 (p < 0.05). Additionally, higher Apgar scores were associated with better outcomes (p < 0.05), with the odds of unfavorable neurological outcomes decreasing by 0.7-fold for every point increase in Apgar score. Furthermore, we found a statistically significant association between preterm birth and unfavorable neurological outcomes (p = 0.0104). Our study highlights the importance of early EEG monitoring in the NICU and provides valuable insights into predictors of unfavorable neurological outcomes in newborns who experienced NS.

Bumetanide potentiates the anti-seizure and disease-modifying effects of midazolam in a noninvasive rat model of term birth asphyxia

Birth asphyxia and the resulting hypoxic-ischemic encephalopathy (HIE) are highly associated with perinatal and neonatal death, neonatal seizures, and an adverse later-life outcome. Currently used drugs, including phenobarbital and midazolam, have limited efficacy to suppress neonatal seizures. There is a medical need to develop new therapies that not only suppress neonatal seizures but also prevent later-life consequences. We have previously shown that the loop diuretic bumetanide does not potentiate the effects of phenobarbital in a rat model of birth asphyxia. Here we compared the effects of bumetanide (0.3 or 10 mg/kg i.p.), midazolam (1 mg/kg i.p.), and a combination of bumetanide and midazolam on neonatal seizures and later-life outcomes in this model. While bumetanide at either dose was ineffective when administered alone, the higher dose of bumetanide markedly potentiated midazolam's effect on neonatal seizures. Median bumetanide brain levels (0.47-0.53 µM) obtained with the higher dose were in the range known to inhibit the Na-K-Cl-cotransporter NKCC1 but it remains to be determined whether brain NKCC1 inhibition was underlying the potentiation of midazolam. When behavioral and cognitive alterations were examined over three months after asphyxia, treatment with the bumetanide/midazolam combination, but not with bumetanide or midazolam alone, prevented impairment of learning and memory. Furthermore, the combination prevented the loss of neurons in the dentate hilus and aberrant mossy fiber sprouting in the CA3a area of the hippocampus. The molecular mechanisms that explain that bumetanide potentiates midazolam but not phenobarbital in the rat model of birth asphyxia remain to be determined.

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.

Prevalence, Risk Factors, and Impact of Preoperative Seizures in Neonates With Congenital Heart Disease

PURPOSE

The purpose of this study was to assess the prevalence, risk factors, and impact of electrographic seizures in neonates with complex congenital heart disease before cardiac surgery.

METHODS

A cohort of 31 neonates with congenital heart disease monitored preoperatively with continuous video-EEG (cEEG) was first reviewed for electrographic seizure burden and EEG background abnormalities. Second, cEEG findings were correlated with brain MRI and 18-month outcomes.

RESULTS

Continuous video-EEG was recorded preoperatively for a median duration of 20.5 hours (range, 2.5-93.5 hours). The five neonates (16%; 95% confidence interval, 5.5% to 34%) with seizures detected on cEEG in the preoperative period had a diagnosis of transposition of the great arteries or similar physiology, detected in four of five postnatally. None of the 157 recorded electrographic seizures had a clinical correlate. The median time to first seizure was 65 minutes (range, 6-300 minutes) after cEEG hookup. The median maximum hourly seizure burden was 12.4 minutes (range, 7-23 minutes). Before the first electrographic seizure, a prolonged interburst interval (>10 seconds) was not associated with seizures (coefficient 1.2; 95% confidence interval, -1.1 to 3.6). MRI brain lesions were three times more common in neonates with seizures. Sharp wave transients on cEEG were associated with delayed opercular development.

CONCLUSIONS

In this cohort, preoperative electrographic seizures were common, were all subclinical, and were associated with MRI brain injury and postnatal diagnosis of transposition of the great arteries. The findings motivate further study of the mechanisms of preoperative brain injury, particularly among neonates with a postnatal diagnosis of transposition of the great arteries.

Neuroprotective therapies in the NICU in term infants: present and future

Outcomes of neonatal encephalopathy (NE) have improved since the widespread implementation of therapeutic hypothermia (TH) in high-resource settings. While TH for NE in term and near-term infants has proven beneficial, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. There is therefore a critical need to find additional pharmacological and non-pharmacological interventions that improve the outcomes for these children. There are many potential candidates; however, it is unclear whether these interventions have additional benefits when used with TH. Although primary and delayed (secondary) brain injury starting in the latent phase after HI are major contributors to neurodisability, the very late evolving effects of tertiary brain injury likely require different interventions targeting neurorestoration. Clinical trials of seizure management and neuroprotection bundles are needed, in addition to current trials combining erythropoietin, stem cells, and melatonin with TH. IMPACT: The widespread use of therapeutic hypothermia (TH) in the treatment of neonatal encephalopathy (NE) has reduced the associated morbidity and mortality. However, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. This review details the pathophysiology of NE along with the evidence for the use of TH and other beneficial neuroprotective strategies used in term infants. We also discuss treatment strategies undergoing evaluation at present as potential adjuvant treatments to TH in NE.

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.

Newborn screening for neurodevelopmental diseases: Are we there yet?

In the US, newborn screening (NBS) is a unique health program that supports health equity and screens virtually every baby after birth, and has brought timely treatments to babies since the 1960's. With the decreasing cost of sequencing and the improving methods to interpret genetic data, there is an opportunity to add DNA sequencing as a screening method to facilitate the identification of babies with treatable conditions that cannot be identified in any other scalable way, including highly penetrant genetic neurodevelopmental disorders (NDD). However, the lack of effective dietary or drug-based treatments has made it nearly impossible to consider NDDs in the current NBS framework, yet it is anticipated that any treatment will be maximally effective if started early. Hence there is a critical need for large scale pilot studies to assess if and how NDDs can be effectively screened at birth, if parents desire that information, and what impact early diagnosis may have. Here we attempt to provide an overview of the recent advances in NDD treatments, explore the possible framework of setting up a pilot study to genetically screen for NDDs, highlight key technical, practical, and ethical considerations and challenges, and examine the policy and health system implications.

Treatment of Neonatal Seizures: Comparison of Treatment Pathways From 11 Neonatal Intensive Care Units

OBJECTIVE

Seizures are a common neonatal neurologic emergency. Many centers have developed pathways to optimize management. We evaluated neonatal seizure management pathways at level IV neonatal intensive care units (NICUs) in the United States to highlight areas of consensus and describe aspects of variability.

METHODS

We conducted a descriptive analysis of 11 neonatal seizure management pathways from level IV NICUs that specialize in neonatal neurocritical care including guidelines for electroencephalography (EEG) monitoring, antiseizure medication (ASM) choice, timing, and dose.

RESULTS

Study center NICUs had a median of 70 beds (interquartile range: 52-96). All sites had 24/7 conventional EEG initiation, monitoring, and review capability. Management pathways uniformly included prompt EEG confirmation of seizures. Most pathways included a provision for intravenous benzodiazepine administration if either EEG or loading of ASM was delayed. Phenobarbital 20 mg/kg IV was the first-line ASM in all pathways. Pathways included either fosphenytoin or levetiracetam as the second-line ASM with variable dosing. Third-line ASMs were most commonly fosphenytoin or levetiracetam, with alternatives including topiramate or lacosamide. All pathways provided escalation to continuous midazolam infusion with variable dosing for seizures refractory to initial medication trials. Three pathways also included lidocaine infusion. Nine pathways discussed ASM discontinuation after resolution of acute symptomatic seizures with variable timing.

CONCLUSIONS

Despite a paucity of data from controlled trials regarding optimal neonatal seizure management, there are areas of broad agreement among institutional pathways. Areas of substantial heterogeneity that require further research include optimal second-line ASM, dosage, and timing of ASM discontinuation.

Neonatal Seizures: Core Concepts

Seizures are the abnormal, excessive, synchronous discharge of cortical neurons that results in injury to the brain. Seizures presenting in the neonatal period may be the first and only clue to underlying neurological pathology. Despite advances in care, the mortality rate for infants experiencing neonatal seizures is still as high as 20 percent, with up to 65 percent of infants with seizures demonstrating significant morbidity. Early identification and treatment of the seizure or modifiable underlying etiology greatly reduces the extent of morbidity associated with neonatal seizures. Literature, including journal articles and relevant textbooks, was reviewed and condensed into a practical guide to neonatal seizures which includes the pathophysiology of injury associated with neonatal seizures, clinical manifestations, methods of diagnosis, and various options available for treatment.

Prognostic Significance of Cyclic Seizures in Status Epilepticus

PURPOSE

Status epilepticus (SE) is a commonly encountered neurologic condition associated with high mortality rates. Cyclic seizures (CS) are a common form of SE, but its prognostic significance has not been well established. In this retrospective study, the mortality of cyclic versus noncyclic forms (NCSs) of SE are compared.

METHODS

A total of 271 patients were identified as having seizures or SE on EEG reports, of which 65 patients were confirmed as having SE. Based on EEG characteristics, the patients were then classified as cyclic or noncyclic patterns. Cyclic seizures were defined as recurrent seizures occurring at nearly regular and uniform intervals. Noncyclic form included all other patterns of SE. Pertinent clinical data were collected and reviewed for each case.

RESULTS

Of the 65 patients with SE, 25 patients had CS and 40 patients had NCS. Patients with CS showed a lower rate of in-hospital mortality although not statistically significant (P = 0.19). When looking at patients younger than 75 years, the CS group had significantly lower in-hospital mortality rate (P = 0.007).

CONCLUSIONS

The findings of this study suggest that CS may have a more favorable outcome compared with NCS in patients younger than 75 years. This study is also the first to report the rate of CS among all cases of confirmed SE (38%). Future studies with a larger sample size are needed to further evaluate the difference in outcome between CS and NCS.

PACS1-Neurodevelopmental disorder: clinical features and trial readiness

Background

PACS1-Neurodevelopmental Disorder (PACS1-NDD) is an ultra-rare condition due to a recurrent mutation in the PACS1 gene. Little systematically collected data exist about the functional abilities and neurodevelopmental morbidities in children with PACS1-NDD

Methods

Parents of individuals with PACS1-NDD completed an on-line survey designed collaboratively by researchers, parents, and clinicians. Analyses focused on those with a confirmed R203W variant.

Results

Of 35 individuals with confirmed variants, 18 (51%) were female. The median age was 8 years (interquartile range 4.5–15). Seventeen (49%) had a diagnosis of epilepsy. Twelve (40%, of 30 responding to the question) reported autism and (N = 11/30, 37%) reported features of autism. Most children walked independently (N = 29/32, 91%), had a pincer grasp (N = 23/32, 72%), could feed themselves independently (N = 15/32, 47%), and used speech (N = 23/32, 72%). Sixteen of twenty-nine (55%) had simple pre-academic skills. Neither epilepsy nor autism was associated with functional abilities or other clinical features (all P > 0.05).

Conclusions

PACS1-NDD is a moderately-severe intellectual disability syndrome in which seizures occur but are not a defining or primary feature. Successful precision medicine clinical trials for this ultra-rare disorder must target important core features of this disorder and utilize assessment tools commensurate with the level of function in this clinical population.

Management of seizures in neonates with neonatal encephalopathy treated with hypothermia

Neonatal encephalopathy (NE) is the most common etiology of acute neonatal seizures - about half of neonates treated with therapeutic hypothermia for NE have EEG-confirmed seizures. These seizures are best identified with continuous EEG monitoring, as clinical diagnosis leads to under-diagnosis of subclinical seizures and over-treatment of events that are not seizures. High seizure burden, especially status epilepticus, is thought to augment brain injury. Treatment, therefore, is aimed at minimizing seizure burden. Phenobarbital remains the mainstay of treatment, as it is more effective than levetiracetam and easier to administer than fosphenytoin. Emerging evidence suggests that, for many neonates, it is safe to discontinue the phenobarbital after acute seizures resolve and prior to hospital discharge.

Treating Seizures after Hypoxic-Ischemic Encephalopathy-Current Controversies and Future Directions

Seizures are common in newborn infants with hypoxic-ischemic encephalopathy and are highly associated with adverse neurodevelopmental outcomes. The impact of seizure activity on the developing brain and the most effective way to manage these seizures remain surprisingly poorly understood, particularly in the era of therapeutic hypothermia. Critically, the extent to which seizures exacerbate brain injury or merely reflect the underlying evolution of injury is unclear. Current anticonvulsants, such as phenobarbital and phenytoin have poor efficacy and preclinical studies suggest that most anticonvulsants are associated with adverse effects on the developing brain. Levetiracetam seems to have less potential neurotoxic effects than other anticonvulsants but may not be more effective. Given that therapeutic hypothermia itself has significant anticonvulsant effects, randomized controlled trials of anticonvulsants combined with therapeutic hypothermia, are required to properly determine the safety and efficacy of these drugs. Small clinical studies suggest that prophylactic phenobarbital administration may improve neurodevelopmental outcomes compared to delayed administration; however, larger high-quality studies are required to confirm this. In conclusion, there is a distinct lack of high-quality evidence for whether and to what extent neonatal seizures exacerbate brain damage after hypoxia-ischemia and how best to manage them in the era of therapeutic hypothermia.

A Pilot Randomized, Controlled, Double-Blind Trial of Bumetanide to Treat Neonatal Seizures

OBJECTIVE

In the absence of controlled trials, treatment of neonatal seizures has changed minimally despite poor drug efficacy. We tested bumetanide added to phenobarbital to treat neonatal seizures in the first trial to include a standard-therapy control group.

METHODS

A randomized, double-blind, dose-escalation design was employed. Neonates with postmenstrual age 33 to 44 weeks at risk of or with seizures were eligible. Subjects with electroencephalography (EEG)-confirmed seizures after ≥20 and <40mg/kg phenobarbital were randomized to receive additional phenobarbital with either placebo (control) or 0.1, 0.2, or 0.3mg/kg bumetanide (treatment). Continuous EEG monitoring data from ≥2 hours before to ≥48 hours after study drug administration (SDA) were analyzed for seizures.

RESULTS

Subjects were randomized to treatment (n = 27) and control (n = 16) groups. Pharmacokinetics were highly variable among subjects and altered by hypothermia. The only statistically significant adverse event was diuresis in treated subjects (48% vs 13%, p = 0.02). One treated (4%) and 3 control subjects died (19%, p = 0.14). Among survivors, 2 of 26 treated subjects (8%) and 0 of 13 control subjects had hearing impairment, as did 1 nonrandomized subject. Total seizure burden varied widely, with much higher seizure burden in treatment versus control groups (median = 3.1 vs 1.2 min/h, p = 0.006). There was significantly greater reduction in seizure burden 0 to 4 hours and 2 to 4 hours post-SDA (both p < 0.01) compared with 2-hour baseline in treatment versus control groups with adjustment for seizure burden.

INTERPRETATION

Although definitive proof of efficacy awaits an appropriately powered phase 3 trial, this randomized, controlled, multicenter trial demonstrated an additional reduction in seizure burden attributable to bumetanide over phenobarbital without increased serious adverse effects. Future trials of bumetanide and other drugs should include a control group and balance seizure severity. ANN NEUROL 2021;89:327-340.

Efficacy and Safety of Phenobarbitone as First-Line Treatment for Neonatal Seizure: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Phenobarbitone is used as a first-line drug for neonatal seizures. However, its poor short- and long-term safety profile is concerning. We aim to systematically synthesize the data on the efficacy and safety of phenobarbitone as a first-line agent and compare it against other anti-epileptic drugs (AEDs) in neonates.

METHODS

Using keywords related to the study population (neonatal seizure) and intervention (phenobarbitone), we searched CENTRAL, Embase, PubMed and Web of Science until 15 December 2020. Randomized controlled trials (RCTs) comparing phenobarbitone with any other AED as first-line therapy for seizure control in the neonates were considered eligible. The random-effect meta-analysis was done using RevMan 5.3 software.

RESULTS

We screened through 443 records and identified nine eligible studies (719 participants). Five RCTs comparing phenobarbitone with levetiracetam did not find any difference in seizure control with the first dose [risk ratio (RR) 1.43, 95% CI 0.79-2.57] or adverse effects (RR 4.66; 95% CI 0.33-65.83). Two trials comparing phenobarbitone and phenytoin also did not find any difference in seizure control with the first dose (RR 2.09; 95% CI 0.31-14.03) and other outcomes. Only one RCT compared phenobarbitone and lorazepam and found lorazepam to be more efficacious in seizure control with the first dose (RR 0.71; 95% CI 0.53-0.94). Three trials compared neurodevelopmental outcomes, in which levetiracetam was better in two, whereas one did not find any difference.

CONCLUSION

Phenobarbitone is at least as efficacious and safe as other drugs like phenytoin and levetiracetam. The data over the long-term neurodevelopmental outcome are lacking. The existing evidence is insufficient to recommend other drugs over phenobarbitone.

Linking acute symptomatic neonatal seizures, brain injury and outcome in preterm infants

Neonatal seizures (NS) are the most frequent sign of neurological dysfunction in newborn infants. With increased survival of preterm neonates, the current clinical focus has shifted from preventing death to improving long-term neurological outcome. In the context of acute symptomatic NS, the main negative prognostic factors include etiology, and severity of brain injury, but also prolonged seizures and especially status epilepticus. However, the reasons for the detrimental contribution of seizures to outcome are still unclear, and evidence has been collected both in favor of seizures being an epiphenomenon of brain injury and of independently contributing to further damage. In this narrative focused review, we will discuss both hypotheses, with special emphasis on data relating to preterm infants. We will also identify present controversies and possible future lines of research.

Expression Pattern of ALOXE3 in Mouse Brain Suggests Its Relationship with Seizure Susceptibility

Arachidonic acid (AA), a polyunsaturated fatty acid, is involved in the modulation of neuronal excitability in the brain. Arachidonate lipoxygenase 3 (ALOXE3), a critical enzyme in the AA metabolic pathway, catalyzes the derivate of AA into hepoxilins. However, the expression pattern of ALOXE3 and its role in the brain has not been described until now. Here we showed that the levels of Aloxe3 mRNA and protein kept increasing since birth and reached the highest level at postnatal day 30 in the mouse hippocampus and temporal cortex. Histomorphological analyses indicated that ALOXE3 was enriched in adult hippocampus, somatosensory cortex and striatum. The distribution was restricted to the neurites of function-specific subregions, such as mossy fibre connecting hilus and CA3 neurons, termini of Schaffer collateral projections, and the layers III and IV of somatosensory cortex. The spatiotemporal expression pattern of ALOXE3 suggests its potential role in the modulation of neural excitability and seizure susceptibility. In fact, decreased expression of ALOXE3 and elevated concentration of AA in the hippocampus was found after status epilepticus (SE) induced by pilocarpine. Local overexpression of ALOXE3 via adeno-associated virus gene transfer restored the elevated AA level induced by SE, alleviated seizure severities by increasing the latencies to myclonic switch, clonic convulsions and tonic hindlimb extensions, and decreased the mortality rate in the pilocarpine-induced SE model. These results suggest that the expression of ALOXE3 is a crucial regulator of AA metabolism in brain, and potentially acts as a regulator of neural excitability, thereby controlling brain development and seizure susceptibility.

High-Dose Levetiracetam for Neonatal Seizures: A Retrospective Review

BACKGROUND

Neonatal seizures are frequently encountered in the neonatal intensive care unit and may be associated with serious long-term neurological sequelae. Response to treatment continues to be modest, and treatment guidelines remain unclear. The use of levetiracetam has been on the rise in the past several years due to its favorable safety profile in the face of limited data on its efficacy and optimal dosing regimens. Unlike the older age groups, the benefit of escalating to high-dose levetiracetam of 80-100 mg/kg/day in neonates not responding to the standard used dosing regimen (40-60 mg/kg/day) is not studied. We sought to investigate the safety and efficacy of levetiracetam escalation to high dose regimens for neonatal seizures.

METHODS

A retrospective chart review over a 7-year period was conducted at the American University of Beirut to identify neonates with electrographically proven seizures treated with levetiracetam. Data was collected on electroclinical seizure characteristics, underlying etiology, seizure control, other anti-seizure medications, and adverse effects.

RESULTS

Electronic chart review revealed a total of 15 neonates with electrographically confirmed seizures treated with levetiracetam, with escalation to high doses in seven. As a first line drug, levetiracetam monotherapy terminated seizures in six out 10 neonates, two of whom had complete seizure cessation only after escalation to high doses of 80 or 100 mg/kg/day. When used in combination with other anti-seizure medications, four out of five neonates achieved complete seizure cessation upon escalation to high doses of levetiracetam. No adverse effects were noted.

CONCLUSIONS

In neonates not responding to the standard used levetiracetam doses, incremental increases to 80-100 mg/kg/day may be considered. Prospective studies are needed to confirm the promising role of such high dosing regimens, and to better elucidate the role of levetiracetam in neonatal seizures.

2-Deoxyglucose terminates pilocarpine-induced status epilepticus in neonatal rats

OBJECTIVE

Neonatal status epilepticus (SE) is a life-threatening medical emergency. Unfortunately, up to 50% of neonates with SE are resistant to current antiseizure drugs, highlighting the need for better treatments. This study aims to explore a novel metabolic approach as a potential alternative treatment to control neonatal SE, using the glycolytic inhibitor 2-deoxyglucose (2-DG).

METHODS

SE was induced by pilocarpine (300 mg/kg, intraperitoneally [ip]) in neonatal Sprague Dawley rats (postnatal day 10 [P10]-P17) and was monitored by video-electroencephalography (V-EEG). After 30 minutes of SE, 2-DG or one of two conventional antiseizure drugs with different mechanisms of action, phenobarbital or levetiracetam, was administrated ip, and V-EEG recording was continued for ~60 additional minutes. The time to seizure cessation after drug injection, EEG scores, and power spectra before and after drug or saline treatment were used to assess drug effects.

RESULTS

Once SE became sustained, administration of 2-DG (50, 100, or 500 mg/kg, ip) consistently stopped behavioral and electrographic seizures within 10-15 minutes; lower doses took longer (25-30 minutes) to stop SE, demonstrating a dose-dependent effect. Administration of phenobarbital (30 mg/kg, ip) or levetiracetam (100 mg/kg, ip) also stopped SE within 10-15 minutes in neonatal rats.

SIGNIFICANCE

Our results suggest that the glycolysis inhibitor 2-DG acts quickly to reduce neuronal hyperexcitability and effectively suppress ongoing seizure activity, which may provide translational value in the treatment of neonatal SE.

Levetiracetam Versus Phenobarbital for Neonatal Seizures: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

There are no US Food and Drug Administration-approved therapies for neonatal seizures. Phenobarbital and phenytoin frequently fail to control seizures. There are concerns about the safety of seizure medications in the developing brain. Levetiracetam has proven efficacy and an excellent safety profile in older patients; therefore, there is great interest in its use in neonates. However, randomized studies have not been performed. Our objectives were to study the efficacy and safety of levetiracetam compared with phenobarbital as a first-line treatment of neonatal seizures.

METHODS

The study was a multicenter, randomized, blinded, controlled, phase IIb trial investigating the efficacy and safety of levetiracetam compared with phenobarbital as a first-line treatment for neonatal seizures of any cause. The primary outcome measure was complete seizure freedom for 24 hours, assessed by independent review of the EEGs by 2 neurophysiologists.

RESULTS

Eighty percent of patients (24 of 30) randomly assigned to phenobarbital remained seizure free for 24 hours, compared with 28% of patients (15 of 53) randomly assigned to levetiracetam (P < .001; relative risk 0.35 [95% confidence interval: 0.22-0.56]; modified intention-to-treat population). A 7.5% improvement in efficacy was achieved with a dose escalation of levetiracetam from 40 to 60 mg/kg. More adverse effects were seen in subjects randomly assigned to phenobarbital (not statistically significant).

CONCLUSIONS

In this phase IIb study, phenobarbital was more effective than levetiracetam for the treatment of neonatal seizures. Higher rates of adverse effects were seen with phenobarbital treatment. Higher-dose studies of levetiracetam are warranted, and definitive studies with long-term outcome measures are needed.

Amplitude-integrated electroencephalography for neonatal seizure detection. An electrophysiological point of view

Seizures in the newborn are associated with high morbidity and mortality, making their detection and treatment critical. Seizure activity in neonates is often clinically obscured, such that detection of seizures is particularly challenging. Amplitude-integrated EEG is a technique for simplified EEG monitoring that has found an increasing clinical application in neonatal intensive care. Its main value lies in the relative simplicity of interpretation, allowing nonspecialist members of the care team to engage in real-time detection of electrographic seizures. Nevertheless, to avoiding misdiagnosing rhythmic artifacts as seizures, it is necessary to recognize the electrophysiological ictal pattern in the conventional EEG trace available in current devices. The aim of this paper is to discuss the electrophysiological basis of the differentiation of epileptic seizures and extracranial artifacts to avoid misdiagnosis with amplitude-integrated EEG devices.

Acute Symptomatic Seizures in Neonates

Seizures are an important sign of neurologic dysfunction in neonates, and they most often represent acute brain injury such as hypoxic-ischemic encephalopathy, stroke, or intracranial hemorrhage (acute symptomatic seizures). Clinical identification of seizures is not reliable since seizures in neonates often do not have an apparent clinical correlate; therefore, electroencephalography should be used to accurately diagnose and manage neonatal seizures. Seizures are refractory to initial loading doses of standard medications in >50% of cases. Since seizures are commonly associated with adverse acute and long-term outcomes, and the seizures themselves may result in additional brain injury, it is important to quickly recognize, diagnose, and treat seizures in neonates. Local practice pathways may optimize efficiency in assessment and treatment for affected newborns. Herein, we review the etiology, methods of diagnosis, treatment, and current knowledge gaps for neonatal seizures.

Assessing the Feasibility of Providing a Real-Time Response to Seizures Detected With Continuous Long-Term Neonatal Electroencephalography Monitoring

PURPOSE

Continuous video electroencephalography (cEEG) monitoring is the recommended gold standard of care for at-risk neonates but is not available in many Neonatal Intensive Care Units (NICUs). To conduct a randomized treatment trial of levetiracetam for the first-line treatment of neonatal seizures (the NEOLEV2 trial), we developed a monitoring infrastructure at five NICUs, implementing recent technological advancements to provide continuous video EEG monitoring and real-time response to seizure detection. Here, we report on the feasibility of providing this level of care.

METHODS

Twenty-five key informant interviews were conducted with study neurologists, neonatologists, coordinators, and EEG technicians from the commercial EEG monitoring company Corticare. A general inductive approach was used to analyze these qualitative data.

RESULTS

A robust infrastructure for continuous video EEG monitoring, remote review, and real-time seizure detection was established at all sites. At the time of this survey, 260 babies had been recruited and monitored for 2 to 6 days. The EEG technician review by the commercial EEG monitoring company was reassuring to families and neonatologists and led to earlier detection of seizures but did not reduce work load for neurologists. Neurologists found the automated neonatal seizure detector algorithm provided by the EEG software company Persyst useful, but the accuracy of the algorithm was not such that it could be used without review by human expert. Placement of EEG electrodes to initiate monitoring, especially after hours, remains problematic.

CONCLUSIONS

Technological advancements have made it possible to provide at-risk neonates with continuous video EEG monitoring, real-time detection of and response to seizures. However, this standard of care remains unfeasible in usual clinical practice. Chief obstacles remain starting a recording and resourcing the real-time specialist review of suspect seizures.

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.

Conventional MRI scan and DTI imaging show more severe brain injury in neonates with hypoxic-ischemic encephalopathy and seizures

BACKGROUND

Neonates with hypoxic-ischemic encephalopathy (HIE) and seizures have poorer outcome for undetermined reasons.

AIMS

Our aim was to determine if brain imaging was more abnormal in neonates with HIE and electrographically confirmed seizures and whether this was impacted by seizure burden.

STUDY DESIGN

Single center retrospective review.

SUBJECTS

Forty-eight term neonates with HIE (with and without seizures) underwent MRI brain scans before age 14 days between the years 2008 and 2013.

OUTCOME MEASURES

Images were rated using a MRI injury score and fractional anisotropy (FA) values were extracted from diffusion tensor imaging (DTI).

RESULTS

The seizure group (n = 25) had significantly more injury within white matter, basal ganglia, posterior limb of internal capsule, and watershed areas compared to the group without seizures (n = 23). The severity of injury in all measured areas increased with increasing seizure severity. The seizure group also had lower FA values in posterior limb of the internal capsule and the splenium of corpus callosum.

CONCLUSIONS

Neonates with HIE and seizures had more brain injury that occurred in areas typically affected by HIE and was greater with higher seizure burden. Seizures may be a marker of more severe brain injury or seizures themselves may amplify brain damage from HIE.

Outcomes After Acute Symptomatic Seizures in Children Admitted to a Neonatal Neurocritical Care Service

BACKGROUND

Neonatal seizures due to acute brain injury are associated with high rates of death, disability, and epilepsy. Our objective was to examine incidence of and risk factors for epilepsy among survivors of acute symptomatic neonatal seizures who were cared for by a neonatal neurocritical care service.

METHODS

Neonates with acute symptomatic seizures who were admitted to UCSF Benioff Children's Hospital Neuro-Intensive Care Nursery from July 2008 to June 2014 were considered for inclusion.

RESULTS

A total of 144 children with acute symptomatic seizures met study criteria and 37 (26%) died before age one. Eighty-seven children (85% of eligible survivors) were followed up to one year or longer. Epilepsy was diagnosed in eight children at median age 4.9 (interquartile range 1.7, 6.1) years. The cumulative incidence risk of epilepsy at one year was 2% (95% confidence interval 0.6% to 9%) and at five years was 7% (95% confidence interval 3% to 20%). Cerebral palsy was diagnosed in 21%. Bayley-III cognitive subscale less than 85 was present in 13%. Children with epilepsy were more likely to be preterm, have brain injury, and be discharged home on antiseizure medication, although the results were not significant after adjusted analysis.

CONCLUSIONS

The risk of epilepsy was lower and age at onset was older than in previous reports, which may be related to multiple factors including a neurocritical care approach, treatment of hypoxic-ischemic encephalopathy with hypothermia, high rate of neonatal transition to palliative care, and the exclusion of neonatal onset epilepsies. Continuation of antiseizure medications in infancy did not decrease the risk of epilepsy. Long-term, multicenter studies are needed to understand whether neonatal seizure management can alter the risk of epilepsy.

Outcomes after acute symptomatic seizures in neonates

Acute symptomatic seizures are a common sign of neurological dysfunction and brain injury in neonates and occur in approximately one to three per 1000 live births. Seizures in neonates are usually a sign of underlying brain injury and, as such, are commonly associated with adverse outcomes. Neurological morbidities in survivors often co-occur; epilepsy, cerebral palsy, and intellectual disability often occur together in the most severely affected children. Risk factors for adverse outcome include prematurity, low Apgar scores, low pH on the first day of life, seizure onset <24 or >72 h after birth, abnormal neonatal neurological examination, abnormal neonatal electroencephalographic background, status epilepticus, and presence and pattern of brain injury (particularly deep gray or brainstem injury). Despite this list of potential indicators, accurate prediction of outcome in a given child remains challenging. There is great need for long-term, multicenter studies to examine risk factors for, and pathogenesis of, adverse outcomes following acute symptomatic seizures in neonates.

Acute symptomatic seizures in term neonates: Etiologies and treatments

Acute symptomatic seizures caused by either diffuse or focal perinatal hypoxic-ischemic insults and intracranial hemorrhage in term newborns make up the large majority of all neonatal seizures. Acute seizures are one of the most common neurological disorders in term newborns who require admission to the neonatal intensive care unit. Despite elucidation of seizure pathogenesis in this population using animal models, treatment is limited by a lack of good evidence-based guidelines because of a paucity of rigorously conducted clinical trials or prospective studies in human newborns. A result of this knowledge gap is that management, particularly drug choice, is guided by clinical experience rather than by data informing drug efficacy and safety. This review summarizes the common etiologies and pathogenesis of acute symptomatic seizures, and the current data informing their treatment, including potential novel drugs, together with a suggested treatment algorithm.

Variability in Preferred Management of Electrographic Seizures in Neonatal Hypoxic Ischemic Encephalopathy

BACKGROUND

Seizures may cause added harm in neonates with hypoxic-ischemic encephalopathy (HIE). Specific recommendations about seizure treatment in this context are lacking. We sought to determine the scope of practice regarding management of non-status epilepticus electrographic-only seizures in this setting.

METHODS

A case-based survey was distributed to members of the Child Neurology Society. Providers were asked about their preferred management strategy for sequential clinical scenarios.

RESULTS

A total of 177 child neurologists responded to the survey. Seventy-seven percent of providers would treat 20 seconds or less of electrographic seizure activity. In a neonate with mild HIE and an electrographic-only seizure, there was no agreement among providers regarding whether to start maintenance therapy in addition to a one-time anti-seizure drug load. In a neonate with moderate HIE on phenobarbital for early electro-clinical seizures, most providers would escalate treatment for ongoing electrographic-only seizures by increasing phenobarbital dosing. In a neonate with severe HIE complicated by status epilepticus on phenobarbital who subsequently develops recurrent electrographic-only seizures, providers varied substantially in their management preferences. For all three cases, 75% to 85% of providers would not change their management preferences based on the absence of a clinical correlate with the electrographic seizure.

CONCLUSIONS

We found marked variability among providers regarding preferred management of non-status epilepticus electrographic-only seizures after HIE. Our results identified specific aspects of electrographic-only seizure management in neonatal HIE where there is limited consensus. These discrepancies may serve as opportunities for future investigation.

Ganaxolone: A New Treatment for Neonatal Seizures

Neonatal seizures are amongst the most common neurologic conditions managed by a neonatal care service. Seizures can exacerbate existing brain injury, induce “de novo” injury, and are associated with neurodevelopmental disabilities in post-neonatal life. In this mini-review, we present evidence in support of the use of ganaxolone, a GABA^A agonist neurosteroid, as a novel neonatal therapy. We discuss evidence that ganaxolone can provide both seizure control and neuroprotection with a high safety profile when administered early following birth-related hypoxia, and show evidence that it is likely to prevent or reduce the incidence of the enduring disabilities associated with preterm birth, cerebral palsy, and epilepsy. We suggest that ganaxolone is an ideal anti-seizure treatment because it can be safely used prospectively, with minimal or no adverse effects on the neonatal brain.

Efficacy and safety of levetiracetam in the management of seizures in neonates

OBJECTIVE

To evaluate the efficacy and safety of levetiracetam (LEV) in the management of seizures in neonates.

METHODS

A prospective non-blind, single arm clinical trial conducted in the Department of Neonatology and Pediatric Intensive Care, Mohamad Kermanshahi, and Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran from May 2014 to December 2014. Fifty out of 60 newborns with gestational age >/=30 weeks with clinically diagnosed seizures were included. Levetiracetam was administered orally with an initial dose of 10 mg/kg twice a day. The patients were observed continuously by Neuro Intensive Care nurses, and visited daily by a neuropediatrician in the first 7 days and then at days 14, 30, and 90 after the start of LEV administration. Clinical examination was performed for every patient, and seizure number, antiepileptic medication, and adverse events were detailed at every visit.

RESULTS

47 infants were seizure free under LEV at the end of the first week, 47 remained seizure free at 4 weeks, and 46 remained seizure free at 11 weeks. No immediate and long-term side effects were noted in our patients.

CONCLUSION

This study investigated the efficacy and safety of LEV in neonatal seizure control but confirmation with further randomized controlled trials is required.

Treatment Duration After Acute Symptomatic Seizures in Neonates: A Multicenter Cohort Study

We aimed to define determinants of duration of treatment for acute symptomatic neonatal seizures in a contemporary multicenter observational cohort study. After adjustment for potential confounders, only study site and seizure etiology remained significantly associated with the chance of continuing antiseizure medication after discharge to home.

Selective head cooling during neonatal seizures prevents postictal cerebral vascular dysfunction without reducing epileptiform activity

Epileptic seizures in neonates cause cerebrovascular injury and impairment of cerebral blood flow (CBF) regulation. In the bicuculline model of seizures in newborn pigs, we tested the hypothesis that selective head cooling prevents deleterious effects of seizures on cerebral vascular functions. Preventive or therapeutic ictal head cooling was achieved by placing two head ice packs during the preictal and/or ictal states, respectively, for the ∼2-h period of seizures. Head cooling lowered the brain and core temperatures to 25.6 ± 0.3 and 33.5 ± 0.1°C, respectively. Head cooling had no anticonvulsant effects, as it did not affect the bicuculline-evoked electroencephalogram parameters, including amplitude, duration, spectral power, and spike frequency distribution. Acute and long-term cerebral vascular effects of seizures in the normothermic and head-cooled groups were tested during the immediate (2-4 h) and delayed (48 h) postictal periods. Seizure-induced cerebral vascular injury during the immediate postictal period was detected as terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive staining of cerebral arterioles and a surge of brain-derived circulating endothelial cells in peripheral blood in the normothermic group, but not in the head-cooled groups. During the delayed postictal period, endothelium-dependent cerebral vasodilator responses were greatly reduced in the normothermic group, indicating impaired CBF regulation. Preventive or therapeutic ictal head cooling mitigated the endothelial injury and greatly reduced loss of postictal cerebral vasodilator functions. Overall, head cooling during seizures is a clinically relevant approach to protecting the neonatal brain by preventing cerebrovascular injury and the loss of the endothelium-dependent control of CBF without reducing epileptiform activity.

Neonatal seizures are associated with redistribution and loss of GABAA α-subunits in the hypoxic-ischaemic pig

Seizures are a common manifestation of hypoxic-ischaemic brain injury in the neonate. In status epilepticus models alterations to GABA_A R subunit expression have been suggested to contribute to (i) abnormal development of the GABAergic system, (ii) why seizures become self-sustaining and (iii) the development of pharmacoresistance. Detailed investigation of GABA_A R subunit protein expression after neonatal hypoxia-ischaemia (HI) is currently insufficient. Using our pig model of HI and subsequent spontaneous neonatal seizures, we investigated changes in protein expression of the three predominant α-subunits of the GABA_A R; α₁ , α₂ and α₃ . Anaesthetized, ventilated newborn pigs (< 24 h old) were subjected to 30 min HI and subsequently recovered to 24 or 72 h. Amplitude-integrated electroencephalography was used to monitor brain activity and identify seizure activity. Brain tissue was collected post-mortem and GABA_A R α-subunit protein expression was analysed using western blot and immunohistochemistry. GABA_A R α₁ and α₃ protein expression was significantly reduced in animals that developed seizures after HI; HI animals that did not develop seizures did not exhibit the same reductions. Immunohistochemistry revealed decreased α₁ and α₃ expression, and α₁ redistribution from the cell membrane to the cytosol, in the hippocampus of seizure animals. Multivariate analyses, controlling for HI severity and neuronal injury, revealed that seizures were independently associated with significant GABA_A R α₃ reduction. This is the first study to show loss and redistribution of GABA_A R α-subunits in a neonatal brain experiencing seizures. Our findings are similar to those reported in models of SE and in chronic epilepsy.

Intellectual abilities in tuberous sclerosis complex: risk factors and correlates from the Tuberous Sclerosis 2000 Study

BACKGROUND

Tuberous sclerosis complex (TSC) is associated with intellectual disability, but the risk pathways are poorly understood.

METHOD

The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of the natural history of TSC. One hundred and twenty-five UK children age 0-16 years with TSC and born between January 2001 and December 2006 were studied. Intelligence was assessed using standardized measures at ≥2 years of age. The age of onset of epilepsy, the type of seizure disorder, the frequency and duration of seizures, as well as the response to treatment was assessed at interview and by review of medical records. The severity of epilepsy in the early years was estimated using the E-Chess score. Genetic studies identified the mutations and the number of cortical tubers was determined from brain scans.

RESULTS

TSC2 mutations were associated with significantly higher cortical tuber count than TSC1 mutations. The extent of brain involvement, as indexed by cortical tuber count, was associated with an earlier age of onset and severity of epilepsy. In turn, the severity of epilepsy was strongly associated with the degree of intellectual impairment. Structural equation modelling supported a causal pathway from genetic abnormality to cortical tuber count to epilepsy severity to intellectual outcome. Infantile spasms and status epilepticus were important contributors to seizure severity.

CONCLUSIONS

The findings support the proposition that severe, early onset epilepsy may impair intellectual development in TSC and highlight the potential importance of early, prompt and effective treatment or prevention of epilepsy in tuberous sclerosis.

Continuous long-term electroencephalography: the gold standard for neonatal seizure diagnosis

Newborn infants at risk for cerebral dysfunction, such as those with acute brain injury or with disorders of brain development, often have encephalopathy and seizures. Conventional electroencephalography (EEG) monitoring can enhance the care of these highly vulnerable patients, through identification of prognostically significant EEG background patterns and accurate diagnosis of seizures and non-seizure paroxysmal events. Neonatal seizures are usually subclinical, and abnormal neonatal movements are often not the result of seizures. Judicious use of conventional EEG monitoring can provide precise diagnosis, quantify seizures, and guide treatment--neonates with EEG-proven seizures should receive appropriate medications and those whose events are not seizures may be spared unnecessary exposure to medications that have potentially important side-effects.

An in vivo screen to identify candidate neurogenic genes in the developing Xenopus visual system

Neurogenesis in the brain of Xenopus laevis continues throughout larval stages of development. We developed a 2-tier screen to identify candidate genes controlling neurogenesis in Xenopus optic tectum in vivo. First, microarray and NanoString analyses were used to identify candidate genes that were differentially expressed in Sox2-expressing neural progenitor cells or their neuronal progeny. Then an in vivo, time-lapse imaging-based screen was used to test whether morpholinos against 34 candidate genes altered neural progenitor cell proliferation or neuronal differentiation over 3 days in the optic tectum of intact Xenopus tadpoles. We co-electroporated antisense morpholino oligonucleotides against each of the candidate genes with a plasmid that drives GFP expression in Sox2-expressing neural progenitor cells and quantified the effects of morpholinos on neurogenesis. Of the 34 morpholinos tested, 24 altered neural progenitor cell proliferation or neuronal differentiation. The candidates which were tagged as differentially expressed and validated by the in vivo imaging screen include: actn1, arl9, eif3a, elk4, ephb1, fmr1-a, fxr1-1, fbxw7, fgf2, gstp1, hat1, hspa5, lsm6, mecp2, mmp9, and prkaca. Several of these candidates, including fgf2 and elk4, have known or proposed neurogenic functions, thereby validating our strategy to identify candidates. Genes with no previously demonstrated neurogenic functions, gstp1, hspa5 and lsm6, were identified from the morpholino experiments, suggesting that our screen successfully revealed unknown candidates. Genes that are associated with human disease, such as such as mecp2 and fmr1-a, were identified by our screen, providing the groundwork for using Xenopus as an experimental system to probe conserved disease mechanisms. Together the data identify candidate neurogenic regulatory genes and demonstrate that Xenopus is an effective experimental animal to identify and characterize genes that regulate neural progenitor cell proliferation and differentiation in vivo.

Prophylactic treatment with melatonin before recurrent neonatal seizures: Effects on long-term neurobehavioral changes and the underlying expression of metabolism-related genes in rat hippocampus and cerebral cortex

Although it has been suggested that the protective effect of melatonin against seizure-induced neurotoxicity involves inhibition of neuronal lipid peroxidation, current data concerning the exact molecular mechanism are still limited. This study was undertaken to investigate the changes in neurobehavioral, cognitive and lipid metabolism-related gene expressions in both hippocampus and cerebral cortex of rats subjected to recurrent neonatal seizures, and the effects of melatonin treatment before seizure (55mg/kg, 1mg/ml). 6-day-old (P6) SD rats were randomly divided into four groups of control (CONT, the same below), melatonin treated control (Mel), recurrent neonatal seizure (RS) and melatonin and RS combination treatment (Mel+RS). Neurological behavioral parameters of brain damage (plane righting reflex, negative geotaxis reaction reflex, Cliff avoidance reflex, forelimb suspension reflex) were observed on P31. Morris water maze test was performed during P29-P35. Then the protein levels of ACAT1, Cathepsin-E and Ca(2+)/calmodulin-dependent protein kinase II (CAMK II) in hippocampus and cerebral cortex were detected by western blot method. As expected, RS group showed a significant delay or reduce of the four reflexes, as well as bad performance in the Morris water maze test. Flurothyl-induced neurobehavioral toxicology was blocked by pre-treatment with melatonin. In parallel with these behavioral changes, gene expression by western blot method demonstrated that rats pretreated with melatonin (Mel+RS) showed a significant down-regulated expression of ACAT-1, Cathepsin-E and up-regulated CAMK II in hippocampus and cerebral cortex when compared with RS group. Our findings provide support for ACAT-1/Cathepsin-E as well as CaMK II being potential targets for the treatment of neonatal seizure-induced brain damage by melatonin.

Enteral supplements of a carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by neonatal seizures

Cerebral blood flow dysregulation caused by oxidative stress contributes to adverse neurologic outcome of seizures. A carbon monoxide (CO) donor CORM-A1 has antioxidant and cytoprotective properties. We investigated whether enteral supplements of CORM-A1 can improve cerebrovascular outcome of bicuculline-induced seizures in newborn piglets. CORM-A1 (2 mg/kg) was given to piglets via an oral gastric tube 10 minutes before or 20 minutes after seizure onset. Enteral CORM-A1 elevated CO in periarachnoid cerebrospinal fluid and produced a dilation of pial arterioles. Postictal cerebral vascular responses to endothelium-, astrocyte-, and vascular smooth muscle-dependent vasodilators were tested 48 hours after seizures by intravital microscopy. The postictal responses of pial arterioles to bradykinin, glutamate, the AMPA receptor agonist quisqualic acid, ADP, and heme were greatly reduced, suggesting that seizures cause injury to endothelial and astrocyte components of the neurovascular unit. In contrast, in the two groups of piglets receiving enteral CORM-A1, the postictal cerebral vascular responsiveness to these dilators was improved. Overall, enteral supplements of CORM-A1 before or during seizures offer a novel effective therapeutic option to deliver cytoprotective mediator CO to the brain, reduce injury to endothelial and astrocyte components of cerebral blood flow regulation and to improve the cerebrovascular outcome of neonatal seizures.

Age-dependent long-term structural and functional effects of early-life seizures: evidence for a hippocampal critical period influencing plasticity in adulthood

Neural activity promotes circuit formation in developing systems and during critical periods permanently modifies circuit organization and functional properties. These observations suggest that excessive neural activity, as occurs during seizures, might influence developing neural circuitry with long-term outcomes that depend on age at the time of seizures. We systematically examined long-term structural and functional consequences of seizures induced in rats by kainic acid, pentylenetetrazol, and hyperthermia across postnatal ages from birth through postnatal day 90 in adulthood (P90). Magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and electrophysiological methods at ⩾P95 following seizures induced from P1 to P90 demonstrated consistent patterns of gross atrophy, microstructural abnormalities in the corpus callosum (CC) and hippocampus, and functional alterations in hippocampal circuitry at ⩾P95 that were independent of the method of seizure induction and varied systematically as a function of age at the time of seizures. Three distinct epochs were observed in which seizures resulted in distinct long-term structural and functional outcomes at ⩾P95. Seizures prior to P20 resulted in DTI abnormalities in CC and hippocampus in the absence of gross cerebral atrophy, and increased paired-pulse inhibition (PPI) in the dentate gyrus (DG) at ⩾P95. Seizures after P30 induced a different pattern of DTI abnormalities in the fimbria and hippocampus accompanied by gross cerebral atrophy with increases in lateral ventricular volume, as well as increased PPI in the DG at ⩾P95. In contrast, seizures between P20 and P30 did not result in cerebral atrophy or significant imaging abnormalities in the hippocampus or white matter, but irreversibly decreased PPI in the DG compared to normal adult controls. These age-specific long-term structural and functional outcomes identify P20-30 as a potential critical period in hippocampal development defined by distinctive long-term structural and functional properties in adult hippocampal circuitry, including loss of capacity for seizure-induced plasticity in adulthood that could influence epileptogenesis and other hippocampal-dependent behaviors and functional properties.

Lower incidence of seizure among neonates treated with therapeutic hypothermia

Animal studies suggest that hypothermia decreases seizure burden, whereas limited human data are inconclusive. This retrospective cohort study examines the relationship between therapeutic hypothermia and seizure in neonates with hypoxic-ischemic encephalopathy. Our center admitted 224 neonates from July 2004 to December 2011 who met institutional cooling criteria. Seventy-three neonates were born during the pre-cooling era, prior to November 2007, and 151 were born during the cooling era. Among neonates with moderate encephalopathy, the incidence of seizure in cooled infants was less than half the incidence in those not cooled (26% cooling, 61% pre-cooling era; risk ratio = 0.43, 95% confidence interval = 0.30-0.61). Among neonates with severe encephalopathy, there was no difference in the incidence (83% vs. 87%; risk ratio = 1.05, 95% confidence interval = 0.78-1.39). These results support animal data and suggest a mechanism by which neonates with moderate encephalopathy can benefit more from cooling than neonates with severe encephalopathy.