Periodic lateralized epileptiform discharges (PLEDs) as early indicator of stroke in full-term newborns

Prognosis of Periodic and Rhythmic Patterns in Adult and Pediatric Populations

Although electrographic seizures are known to have an outcome on clinical prognosis, the implications of periodic and rhythmic patterns are less clear. The outcomes of adults with these patterns have been reported and are often poor; however, the outcomes in pediatric populations are less well characterized and may be different than in the adult population, as the etiologies of periodic and rhythmic patterns may differ in children and adults. In adults, generalized periodic discharges are highly associated with toxic-metabolic disturbances, infection, and anoxic injury; 30% to 64% of patients have poor outcomes. By contrast, in pediatric patients, generalized periodic discharges are more commonly associated with refractory status epilepticus, with good outcomes in 50% to 77%. The underlying etiology of the periodic or rhythmic pattern has a large influence on overall morbidity and mortality.

Continuous electroencephalography predicts delayed cerebral ischemia after subarachnoid hemorrhage: A prospective study of diagnostic accuracy

OBJECTIVE

Delayed cerebral ischemia (DCI) is a common, disabling complication of subarachnoid hemorrhage (SAH). Preventing DCI is a key focus of neurocritical care, but interventions carry risk and cannot be applied indiscriminately. Although retrospective studies have identified continuous electroencephalographic (cEEG) measures associated with DCI, no study has characterized the accuracy of cEEG with sufficient rigor to justify using it to triage patients to interventions or clinical trials. We therefore prospectively assessed the accuracy of cEEG for predicting DCI, following the Standards for Reporting Diagnostic Accuracy Studies.

METHODS

We prospectively performed cEEG in nontraumatic, high-grade SAH patients at a single institution. The index test consisted of clinical neurophysiologists prospectively reporting prespecified EEG alarms: (1) decreasing relative alpha variability, (2) decreasing alpha-delta ratio, (3) worsening focal slowing, or (4) late appearing epileptiform abnormalities. The diagnostic reference standard was DCI determined by blinded, adjudicated review. Primary outcome measures were sensitivity and specificity of cEEG for subsequent DCI, determined by multistate survival analysis, adjusted for baseline risk.

RESULTS

One hundred three of 227 consecutive patients were eligible and underwent cEEG monitoring (7.7-day mean duration). EEG alarms occurred in 96.2% of patients with and 19.6% without subsequent DCI (1.9-day median latency, interquartile range = 0.9-4.1). Among alarm subtypes, late onset epileptiform abnormalities had the highest predictive value. Prespecified EEG findings predicted DCI among patients with low (91% sensitivity, 83% specificity) and high (95% sensitivity, 77% specificity) baseline risk.

INTERPRETATION

cEEG accurately predicts DCI following SAH and may help target therapies to patients at highest risk of secondary brain injury. Ann Neurol 2018;83:958-969.

Analysis of Epileptic Discharges from Implanted Subdural Electrodes in Patients with Sturge-Weber Syndrome

OBJECTIVE

Almost two-thirds of patients with Sturge-Weber syndrome (SWS) have epilepsy, and half of them require surgery for it. However, it is well known that scalp electroencephalography (EEG) does not demonstrate unequivocal epileptic discharges in patients with SWS. Therefore, we analyzed interictal and ictal discharges from intracranial subdural EEG recordings in patients treated surgically for SWS to elucidate epileptogenicity in this disorder.

METHODS

Five intractable epileptic patients with SWS who were implanted with subdural electrodes for presurgical evaluation were enrolled in this study. We examined the following seizure parameters: seizure onset zone (SOZ), propagation speed of seizure discharges, and seizure duration by visual inspection. Additionally, power spectrogram analysis on some frequency bands at SOZ was performed from 60 s before the visually detected seizure onset using the EEG Complex Demodulation Method (CDM).

RESULTS

We obtained 21 seizures from five patients for evaluation, and all seizures initiated from the cortex under the leptomeningeal angioma. Most of the patients presented with motionless staring and respiratory distress as seizure symptoms. The average seizure propagation speed and duration were 3.1 ± 3.6 cm/min and 19.4 ± 33.6 min, respectively. Significant power spectrogram changes at the SOZ were detected at 10-30 Hz from 15 s before seizure onset, and at 30-80 Hz from 5 s before seizure onset.

SIGNIFICANCE

In patients with SWS, seizures initiate from the cortex under the leptomeningeal angioma, and seizure propagation is slow and persists for a longer period. CDM indicated beta to low gamma-ranged seizure discharges starting from shortly before the visually detected seizure onset. Our ECoG findings indicate that ischemia is a principal mechanism underlying ictogenesis and epileptogenesis in SWS.

Early postnatal EEG features of perinatal arterial ischaemic stroke with seizures

Background

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

Objective

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

Design

Retrospective observational study.

Patients

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

Method

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

Results

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

Conclusions

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

Early continuous video electroencephalography in neonatal stroke

Perinatal stroke is the second most common cause of neonatal seizures, and can result in long-term neurological impairment. Diagnosis is often delayed until after seizure onset, owing to the subtle nature of associated signs. We report the early electroencephalographic (EEG) findings in a female infant with a perinatal infarction, born at 41 weeks 2 days and weighing 3.42 kg. Before the onset of seizures, the EEG from 3 hours after delivery demonstrated occasional focal sharp waves over the affected region. After electroclinical seizures, focal sharp waves became more frequent, complex, and of higher amplitude, particularly in 'quiet sleep'. In 'active sleep', sharp waves often disappeared. Diffusion-weighted imaging confirmed the infarct, demonstrating left frontal and parietal diffusion restriction. At 9 months, the infant has had no further seizures, and neurological examination is normal. To our knowledge, this report is the first to describe the EEG findings in perinatal stroke before seizures, and highlights the evolution of characteristic background EEG features.

Symptomatic epilepsy in children with poroencephalic cysts secondary to perinatal middle cerebral artery occlusion

BACKGROUND

Perinatal cerebral artery occlusion is responsible for ischemic cerebral infarction leading to brain cavitation and gliosis; the territory of the middle cerebral artery is most frequently involved. The resulting poroencephalic cysts are frequently associated with hemiplegia and epilepsy; that can be managed medically in most cases, only 6-7% of them being refractory to medical treatment. This particular subset of congenitally hemiplegic children will be possible candidates for electrophysiological investigation and eventually for resective surgery. Whatever the kind of surgical treatment, surgery should be performed as soon as possible to optimize functional brain reorganization.

CLINICAL MATERIAL

Twelve children with poroencephalic cysts and refractory epilepsy were studied and operated on at the Divisions of Child Neurology and Pediatric Neurosurgery, the Catholic University Medical School, Rome. The hemiparesis ranged from mild to moderate; the developmental delay was of mild degree in three cases, moderate in four cases and severe in the remaining five. Behavioral disorders were observed in patients with mental retardation; two of them also manifested autistic features. All the children presented with a severe epileptic syndrome (starting almost invariably during the first year of life); six patients presented with a West syndrome followed by symptomatic partial epilepsy; the other six presented with partial epilepsy, followed in two cases by continuous spike-waves during sleep. The electroencephalograph (EEG) recordings disclosed focal unilateral interictal epileptiform abnormalities that usually corresponded to the side of the cystic lesion; however, paroxysmal activity often spread synchronously over the contralateral hemisphere. The selection of candidates for surgical treatment was based on neuroimaging and video-EEG monitoring; in particular, we did not use invasive intraoperative neurophysiologic techniques. The convergence of neuroimaging and neurophysiologic findings guided us in performing a limited cortical excision corresponding to the malacic cortex (cyst "membrane").

RESULTS

All the patients underwent excision of the cyst wall. Careful attention was paid not to enter the body of the lateral ventricle to avoid ventriculo-subarachnoid fistulas, eventually responsible for subdural hygroma or cerebrospinal fluid leak. There was one surgery-related death secondary to disseminated intravascular coagulation, following an otherwise uneventful surgical procedure. An elevated systemic blood pressure, secondary to repeated adrenocorticotropic hormone therapy, can represent a possible concurrent factor for this event. No major complications were recorded among the remaining 11 children. Seizure control was excellent in all the 11 survivors in the early postoperative period. Two children presented a relapse of seizures, after an initial improvement, respectively 3 and 4 years after the operation. These two children underwent subsequently a functional hemispherectomy. Overall, seizure outcome was excellent in all the cases. Seven patients (including the two who underwent functional hemispherectomy) are seizure-free (Engel's class Ia), and in one of them antiepileptic therapy has been weaned. In the remaining five children, seizures are sporadic and definitely improved (Engel's class II). An improvement of developmental delay, in particular of cognitive competence, was registered in 8 out of the 11 patients. Two of the four severely retarded children, who also presented behavioral abnormalities, did not show any cognitive improvement, whereas some mild improvement of their basal abilities was demonstrated in the other two. All the remaining children, even though maintaining a moderate retardation, definitely improved their abilities; in particular, one of them reached an almost borderline level. The three patients with unchanged neurodevelopmental delay presented also persistent seizures. On the other hand, two children with persistent seizures presented neurodevelopmental improvement.

CONCLUSIONS

Simple surgical excision of the cyst "membrane" of epileptogenic poroencephalic cysts can represent an excellent means to control epilepsy in affected children. However, postoperative seizure persistence and late recurrences, although rare, do not allow to exclude that hemispherectomy or partial resections (based on electrocorticography findings) might represent the good answer at least in some cases.

The clinical outcomes of neonatal and childhood stroke: review of the literature and implications for future research

A detailed assessment of clinical outcomes after ischemic stroke in childhood is necessary to evaluate prognostic factors. Previous studies are difficult to compare because of differences in test instruments, study design, heterogeneity of cohorts and number of included cases. Depending on neurodevelopmental assessment methods, major and subtle/minor disabilities, especially in infants, may not have been detected. Most outcome studies reveal only limited information about behavioral changes and quality of life in children with ischemic stroke. Thus the assumption that children make a better recovery from stroke than adults due to the immature brain's capacity to reorganize function is not evidence-based. We systematically review the current literature with regard to the neurological and psychosocial development of affected children as well as their quality of life. Implications for future research strategies follow the review to encourage further clinical study of the neurobehavioral trajectory of childhood stroke.

Indications de l'électroencéphalogramme en période néonatale

The electroencephalogram (EEG), an easy-to-use and non invasive cerebral investigation, is a useful tool for diagnosis and early prognosis in newborn babies. In newborn full term babies manifesting abnormal clinical signs, EEG can point focal lesions or specific aetiology. EEG background activity and sleep organization have a high prognostic value. Tracings recorded over long period can detect seizures, with or without clinical manifestations, and differentiate them from paroxysmal non epileptic movements. The EEG should therefore be recorded at the beginning of the first symptoms, and if possible before any seizure treatment. When used as a neonatal prognostic tool, EEG background activity is classified as normal, abnormal (type A and type B discontinuous and hyperactive rapid tracing) or highly abnormal (inactive, paroxysmal, low voltage plus theta tracing). In such cases, the initial recording must be made between 12 and 48 h after birth, and then between 4 and 8 days of life. Severe EEG abnormalities before 12 h of life have no reliable prognostic value but may help in the choice of early neuroprotective treatment of acute cerebral hypoxia-ischemia. During presumed hypoxic-ischemic encephalopathy, unusual EEG patterns may indicate another diagnosis. In premature newborn babies (29-32 w GA) with neurological abnormalities, EEG use is the same as in term newborns. Without any neurological abnormal sign, EEG requirements depend on GA and the mother's or child's risk factors. Before 28 w GA, when looking for positive rolandic sharp waves (PRSW), EEG records are to be acquired systematically at D2-D3, D7-D8, 31-32 and 36 w GA. It is well known that numerous and persistent PRSW are related to periventricular leukomalacia (PVL) and indicate a bad prognosis. In babies born after 32 GA with clinically severe symptoms, an EEG should be performed before D7. Background activity, organization and maturation of the tracing are valuable diagnosis and prognosis indicators. These recommendations are designed (1) to get a maximum of precise informations from a limited number of tracings and (2) to standardize practices and thus facilitate comparisons and multicenter studies.

[EEG and ischemic stroke in full-term newborns]

The aims of this study were to describe EEG anomalies in unilateral neonatal ischemic stroke without hypoxic-ischemic encephalopathy, and to determine possible links between these abnormalities and long-term outcome. In 6 full-term newborns without severe fetal distress ischemic stroke was confirmed by computed tomography and/or magnetic resonance imaging. Twenty EEGs were recorded during the neonatal period, 5 in acute stage and 15 later. The duration of the follow-up ranged from 3 to 9 years. All newborns developed unilateral clonic seizures, right-sided (5 cases) or left-sided (1 case); seizures began between 14 and 48 h of life. At follow-up, 3 children were normal at 2 and 6 years of age, while the 3 others had sequelae: epilepsy at 9 years of age in one, and unilateral mild cerebral palsy in the 2 others (3 and 4 years of age), with behavioral problems in one of them. Critical EEG discharges, rhythmic sharp waves and/or slow waves were recorded on the injured side. Abnormalities of interictal activity were excess of alpha or theta rhythms, transitory EEG discontinuity or low voltage. The 2 children with cerebral palsy had numerous unilateral post-ictal positive rolandic slow sharp waves (PRSSWs), which were similar to the positive rolandic sharp waves of premature infants; the child with behavioral problems had numerous positive left-sided temporal fast sharp waves. PRSSWs could be associated with contralateral motor sequelae, while positive left temporal fast sharp waves were associated with long term behavioral problems. These findings may be used for future prospective studies aimed at specifying the relation between EEG abnormalities and long-term outcome.

Periodic lateralized epileptiform discharges of pediatric patients in Taiwan

Periodic lateralized epileptiform discharges are special electroencephalographic abnormalities present in adults with stroke, brain tumor, intracranial hemorrhage, or other rare etiologies. Few reports focused on the etiologies in pediatric patients. We retrospectively reviewed 8002 of our pediatric electroencephalographic records for the past 12 years and listed all associated illness and their outcomes. Forty-four children with periodic lateralized epileptiform discharges were collected. We found that there was an obvious difference in etiologies of our pediatric patients from those reported in the literature. Nearly two thirds of our patients (28 children) were associated with central nervous system infections. The other etiologies included head injury, encephalopathy, epilepsy, and others. Herpes simplex virus was responsible for two thirds (12) of the 18 children with identified pathogens causing a central nervous system infection. Ten patients failed to have a defined pathogen. Periodic lateralized epileptiform discharges have a different clinical significance in pediatric patients than in adults. In Taiwan, central nervous system infection is the most common etiology of periodic lateralized epileptiform discharges in pediatric patients. Herpes simplex virus, although the most common pathogen, should not be considered to be the only cause of encephalitis in children with periodic lateralized epileptiform discharges.

Epidemiology of perinatal stroke

Perinatal stroke has become increasingly recognized, but the incidence is probably underestimated because of variation in the presentation, evaluation, and diagnosis. Based on estimates from population-based studies of infants with seizures, perinatal stroke occurs in approximately 1 in 4000 term births. Most perinatal strokes involve the middle cerebral artery and are caused by thromboembolism from an intracranial or extracranial vessel, the heart, or the placenta. Cardiac disorders, coagulation abnormalities, and infection are risk factors for stroke in the perinatal period. This article discusses the epidemiology of ischemic stroke occurring in the perinatal and neonatal period, including cerebrovascular events that are diagnosed during the perinatal period and those diagnosed retrospectively, when evidence of hemiparesis or postneonatal seizures leads to later evaluation and neuroimaging.