Non-linear EEG analysis in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES)

OBJECTIVE: The objective of this work was to study the non-linear aspects of electroencephalography (EEG) in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES). METHODS: In this study, we recorded the sleep EEG in 5 subjects with ESES (4 males and one female, aged 6.5-10 years) who were also mentally retarded and affected by cerebral palsy (3 subjects) and hydrocephalus (two subjects). The signals were sampled at 128Hz and stored on hard disk. All the subsequent computational steps were performed on EEG epochs (4096 data points) selected from wakefulness and non-rapid eye movement (non-REM) (with ESES) or REM sleep. The dynamic properties of the EEG were assessed by means of the non-linear cross prediction (NLCP) test which uses 3 different 'model' time series in order to predict non-linearly the original data set (Pred, Ama and Tir). Pred is a measure of the predictability of the time series and Ama and Tir are measures of asymmetry, indicating non-linear structure. Moreover, the correlation dimension (D2) was estimated by means of the algorithm by for the epochs showing non-linear nature. RESULTS: The NLCP test provided evidence of significant non-linear dynamics in all epochs of non-REM sleep, when ESES was evident. Only during this stage, the possible presence of low-dimensional chaos could also be suspected (average D2=4.02; range 3.16-6.21). EEG without ESES could not be distinguished from linearly filtered noise. CONCLUSIONS: The results of the present study seem to indicate that subjects with ESES show a profound modification of their EEG dynamics with the occurrence, during sleep, of long periods characterized by non-linear dynamics and, probably, low-dimensional chaotic structure able to modify in a substantial way their brain functioning during sleep.     

The effect of surgery in encephalopathy with electrical status epilepticus during sleep

Purpose: We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery. Methods: All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies. Key Findings: Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one‐way interhemispheric propagation in nine patients and with two‐way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6–9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I–II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I–II outcome had SES with two‐way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch‐up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75. Significance: Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis.     

Atypical language impairment in two siblings: relationship with electrical status epilepticus during slow wave sleep

We report the case of a young girl who presented severe learning disabilities in oral and written language related to a continuous spike-waves during slow sleep (CSWS) syndrome. A sleep EEG recording obtained in her younger brother, who presented a clinical pattern suggesting developmental dysphasia, also showed a CSWS syndrome. These two clinical cases underscore the need to look for this syndrome in the siblings of an affected child when learning difficulties appear in a child who previously had normal psychomotor development.     

Predictors of refractoriness in a Turkish status epilepticus data bank

Refractory status epilepticus (RSE) is known to constitute approximately 10–50% of all cases of status epilepticus (SE) and is associated with significant morbidity and mortality. In the present study, data from a prospectively collected SE database were analyzed. Patients with RSE (defined as a SE episode requiring a second line of intravenous treatment following intravenous phenytoin) were compared with patients with nonrefractory SE (NRSE); 290 episodes of SE were identified, of which 108 (38%) were defined as RSE. Univariate analysis revealed that age, female gender, SE type, SE duration, and acute etiology were associated with refractoriness, whereas electroencephalographic patterns were not. Nonconvulsive SE, which is probably associated with delays in treatment initiation, was a predictor of RSE, although it was not retained as a predictor in multivariate analysis. In the latter analysis, female gender (odds ratio: 1.815, 95% CI: 1.053–3.126) and acute etiology (odds ratio: 0.619, 95% CI: 0.429–0.894) were shown to be the only significant independent predictors of refractoriness.     

Functional brain connectivity in electrical status epilepticus in sleep

Aims. Electrical status epilepticus in sleep (ESES) is an age‐related, self‐limited epileptic encephalopathy. The syndrome is characterized by cognitive and behavioral abnormalities and a specific EEG pattern of continuous spikes and waves during slow‐wave sleep. While spikes and sharp waves are known to result in transient cognitive impairment during learning and memory tasks performed during the waking state, the effect of epileptiform discharges during sleep on cognition and behavior is unclear. There is increasing evidence that abnormalities of coherence, a measure of the consistency of the phase difference between two EEG signals when compared over time, is an important feature of brain oscillations and plays a role in cognition and behavior. The objective of this study was to determine whether coherence of EEG activity is altered during slow‐wave sleep in children with ESES when compared to typically developing children. Methods. We examined coherence during epochs of ESES versus epochs when ESES was not present. In addition, we compared coherence during slow‐wave sleep between typically developing children and children with ESES. Results. ESES was associated with remarkably high coherences at all bandwidths and most electrode pairs. While the high coherence was largely attributed to the spikes and spike‐and‐wave discharge, activity between spikes and spike‐and‐wave discharge also demonstrated high coherence. Conclusions. This study indicates that EEG coherence during ESES is relatively high. Whether these increases in coherence correlate with the cognitive and behavioral abnormalities seen in children with this EEG pattern remains to be determined.     

Serum inflammatory mediators correlate with disease activity in electrical status epilepticus in sleep (ESES) syndrome

We aimed to study serum cytokine levels in 11 electrical status epilepticus in sleep (ESES) patients and 20 healthy control children. Patients showed significantly higher levels of interleukin (IL)‐1α, IL‐6, IL‐10, chemokine (C‐C motif) ligand (CCL)2 and chemokine (C‐X‐C motif) ligand (CXCL)8/IL‐8 than controls, while macrophage migration inhibitory factor (MIF) and CCL3 were significantly lower. Follow‐up analyses in five patients revealed a significant decrease of IL‐6 levels after immunomodulating treatment. IL‐6 changes were accompanied by clear improvement of electroencephalography (EEG) patterns and neuropsychological evaluation. We hypothesize that IL‐6 correlates with disease activity and immunomodulating treatment efficacy.     

Surgical management of pediatric patients with encephalopathy due to electrical status epilepticus during sleep (ESES)

Aims: ESES is a developmental epileptic disorder directly responsible for progressive encephalopathy and neurocognitive regression. The natural history, indications for surgical intervention, and predictors for favorable seizure and neuropsychological outcome remain unclear. Methods: We performed a retrospective review of children who underwent resective or disconnective surgery for ESES between January 2009 and July 2016 at a large tertiary pediatric center. Information on the patients’ demographics, seizure semiology, radiographic and electrographic findings, and surgical management was collected. The primary outcome was seizure freedom at last follow‐up visit, and secondary outcomes were neuropsychological improvement and electrographic ESES resolution. Results: We identified 11 children who underwent surgery for ESES. The mean ages were 3.2 years for seizure onset, 7.1 years for formal ESES diagnosis, and 9.4 years for surgery. Seizure etiologies included cortical malformations (four patients), encephalomalacia and gliosis from prior hemorrhage or tumor resections (three patients), developmental porencephaly (one patient), and Rasmussen's encephalitis (one patient); the etiology was unknown in two children. Preoperatively, nine children had motor deficits, seven had speech and language delay, and three had visual field defects. All children had seizures and neuropsychological regression prior to surgical consideration. Focal cortical resections were performed in seven children, and hemispherectomies in four. Post‐operatively, nine children experienced decreased seizure frequency, eight had neuropsychological improvement, and nine had resolution of electrographic ESES. Patients with poor surgical outcomes had more significant pre‐operative comorbidities, in addition to bilateral ESES activity. Conclusion: In this case series, surgery for a carefully selected group of children with ESES is safe and feasible, yielding rates of seizure freedom and neuropsychological improvement that compare favorably with previous reports for antiepileptic drugs, benzodiazepines, and steroids. As we gain greater understanding into the management of ESES, surgery is an increasingly useful tool for patients with mild or moderate neurodevelopmental delay, focal epileptogenic foci, and hemi‐ESES electrographic findings.     

抗癫癎药物对儿童临床下癎性电持续状态及认知功能的影响

目的：探讨抗癫?药物（AED）对临床发作已控制,但脑电图（EEG）上仍存在癫?性电持续状态ESES患者的认知功能的影响。方法：收集2013年3月～2015年11月本院门诊、住院治疗的儿童癫?患者,用日本光电9000型长程录像脑电图（V‐EEG）监测到的16例临床下ESES患者,临床无发作均超过半年,随访观察,调整治疗方案前后均再进行神经心理学评估和V‐EEG监测。结果：16例应用卡马西平（CBZ）、奥卡西平（OXC）临床发作均已得到控制,V‐EEG提示仍存在ESES现象,神经心理学评估均存在不同程度的认知功能障碍,治疗方案调整为丙戊酸钠／丙戊酸镁、左乙拉西坦／托吡酯,3个月后复查V‐EEG提示ESES消失,脑功能状态得到改善（P＜0．05）。结论：AED的治疗目的,不仅要控制临床发作,也要控制临床下?样放电,特别是ESES现象。     

GRIN2A mutations in epilepsy-aphasia spectrum disorders

Objective

Epilepsy-aphasia spectrum (EAS) are a group of epilepsy syndromes denoting an association between epilepsy, speech disorders and the EEG signature of centrotemporal spikes. Mutations in the GRIN2A gene, encoding the NMDA glutamate receptor α2 subunit were reported in focal epilepsy with speech disorder. We aimed to explore the role of GRIN2A mutations in patients with centrotemporal spikes related epileptic syndromes in a Chinese cohort.

Acetazolamide for electrical status epilepticus in slow‐wave sleep

Electrical status epilepticus in slow‐wave sleep (ESES) is characterized by nearly continuous spike–wave discharges during non–rapid eye movement (REM) sleep. ESES is present in Landau‐Kleffner syndrome (LKS) and continuous spike and wave in slow‐wave sleep (CSWS). Sulthiame has demonstrated reduction in spike–wave index (SWI) in ESES, but is not available in the United States. Acetazolamide (AZM) is readily available and has similar pharmacologic properties. Our aims were to assess the effect of AZM on SWI and clinical response in children with LKS and CSWS. Children with LKS or CSWS treated with AZM at our institution were identified retrospectively. Pre‐ and posttherapy electroencephalography (EEG) studies were evaluated for SWI. Parental and teacher report of clinical improvement was recorded. Six children met criteria for inclusion. Three children (50%) demonstrated complete resolution or SWI <5% after AZM. All children had improvement in clinical seizures and subjective improvement in communication skills and school performance. Five of six children had subjective improvement in hyperactivity and attention. AZM is a potentially effective therapy for children with LKS and CSWS. This study lends to the knowledge of potential therapies that can be used for these disorders, which can be challenging for families and providers.     

Clinical spectrum and medical treatment of children with electrical status epilepticus in sleep (ESES)

Purposes:   To describe the clinical spectrum and to evaluate the efficacy of different therapeutic agents in children with electrical status epilepticus in sleep (ESES).
Methods:   Clinical data of all patients with ESES (not including patients with Landau-Kleffner syndrome) in four pediatric neurology outpatient clinics were analyzed. Thirty patients with ESES had been treated between 1994 and 2007.
Results:   Eleven (37%) children had benign partial epilepsies of childhood, five (17%) had cerebral palsy, five (17%) had hydrocephalus, one (3%) had schizencephaly, one (3%) had prenatal parenchymal bleeding, and the etiology was unclear in seven (23%). The duration of ESES ranged between 2 and 60 months. The antiepileptic drugs that were found to be efficacious were: levetiracetam (41%), clobazam (31%), and sulthiame (17%). Valproic acid, lamotrigine, topiramate, and ethosuximide showed no efficacy. Steroids were efficacious in 65%; immunoglobulins were efficacious in 33%. High-dose diazepam was efficacious in 37%, but all the children had temporary response. Seventeen patients (57%) had cognitive deterioration, whereas the rest presented with regression in attention, speech, communication, and behavior. Fourteen children had permanent cognitive deficit. There was a significant correlation (p = 0.029) between the duration of ESES and residual intellectual deficit at follow-up.
Conclusions:   ESES reflects an evolution of benign partial epilepsy of childhood in more than one-third of the patients, whereas there is an underlying structural brain anomaly in another one-third. The most efficacious antiepileptic drugs (AEDs) are levetiracetam and clobazam. The duration of ESES correlated significantly with residual intellectual deficit at follow-up.     

Measuring spike strength in patients with continuous spikes and waves during sleep: Comparison of methods for prospective use as a clinical index

ObjectiveTo compare methods of estimating spike strength as a potential index in the assessment of continuous spikes and waves during sleep (CSWS).MethodsSpikes were searched and averaged automatically from pre- and postoperative EEGs of ten patients with CSWS who underwent corpus callosotomy (eight) or resective epilepsy surgery (two). From the most prominent spike, we measured peak amplitude and root mean square (RMS) over ±150 ms window around the peak. In order to compensate for spatiotemporal instability of spikes, the cumulative amplitude and RMS were computed from the highest quartile of electrodes (Ampl-Q and RMS-Q, respectively). The stability of parameters was studied by comparing two ten minute epochs during the first hour of NREM sleep, as well as by analyzing overnight variation of indices in further ten patients with CSWS. The Ampl-Q and RMS-Q were compared between pre- and postoperative recordings.ResultsAll four measures, amplitude, RMS, Ampl-Q and RMS-Q, were correlated with each other and highly dependent on NREM/REM-sleep stage and arousals. Expectedly, Ampl-Q and RMS-Q had the greatest intra-individual stability. The amplitude had up to 71% intra-individual variation making it unhelpful for clinical use. Ampl-Q and RMS-Q were comparable in assessing change following surgical treatment.ConclusionsComputing an integrated RMS over multiple electrodes during steady NREM sleep offers a stable and reliable parameter for evaluating the strength of spikes in CSWS.SignificanceAnalyzing spike strength with RMS-Q may offer a clinically useful, supplementary index for EEG monitoring of CSWS where spike index has been of limited value.     

A de novo GABRB2 variant associated with myoclonic status epilepticus and rhythmic high‐amplitude delta with superimposed (poly) spikes (RHADS)

We report a child who developed myoclonic status epilepticus (MSE) at four months of age, associated with rhythmic high‐amplitude delta and superimposed (poly) spikes (RHADS), harbouring a GABRB2 (β2 subunit of the GABA A receptor) variant. The patient was treated under a presumptive diagnosis of neonatal‐onset alpers syndrome (AS) and underwent targeted sequence analysis for POLG1 (polymerase gamma 1) and subsequent whole‐exome sequence analysis (WES). The patient is currently a 10‐year, eight‐month‐old boy, suffering from daily MSE associated with RHADS and severe global developmental delay from early infancy. Although POLG1 mutation was negative, WES revealed a de novo missense variant of GABRB2 (NM_021911.2: c.784G>T, p.[Val262Phe]). Based on a review of case series with GABRB2 variants, we found that five of the 18 cases shared the clinical and EEG characteristics associated with our patient. In summary, this de novo GABRB2 variant was associated with an AS phenotype, characterized by treatment‐resistant MSE and RHADS, and may represent an alternative aetiology for neonatal‐onset AS without POLG1 mutation [Published with video sequence].     

Gaps and opportunities in refractory status epilepticus research in children: A multi-center approach by the Pediatric Status Epilepticus Research Group (pSERG)

PurposeStatus epilepticus (SE) is a life-threatening condition that can be refractory to initial treatment. Randomized controlled studies to guide treatment choices, especially beyond first-line drugs, are not available. This report summarizes the evidence that guides the management of refractory convulsive SE (RCSE) in children, defines gaps in our clinical knowledge and describes the development and works of the ‘pediatric Status Epilepticus Research Group’ (pSERG).MethodsA literature review was performed to evaluate current gaps in the pediatric SE and RCSE literature. In person and online meetings helped to develop and expand the pSERG network.ResultsThe care of pediatric RCSE is largely based on extrapolations of limited evidence derived from adult literature and supplemented with case reports and case series in children. No comparative effectiveness trials have been performed in the pediatric population. Gaps in knowledge include risk factors for SE, biomarkers of SE and RCSE, second- and third-line treatment options, and long-term outcome.ConclusionThe care of children with RCSE is based on limited evidence. In order to address these knowledge gaps, the multicenter pSERG was established to facilitate prospective collection, analysis, and sharing of de-identified data and biological specimens from children with RCSE. These data will allow identification of treatment strategies associated with better outcomes and delineate evidence-based interventions to improve the care of children with SE.     

Propofol-associated fatal myocardial failure and rhabdomyolysis in an adult with status epilepticus

Propofol is increasingly used for the treatment of status epilepticus due to the ease of use and tolerability, even if safety data from randomized clinical trials are lacking. An association of high infusion rates of propofol (>5 mg/kg/h) for more than 48 h and constellation of acidosis, rhabdomyolysis, and cardiovascular collapse has been reported in children, but has only been described in a few adult cases. We report a case and autopsy findings of an adult who developed rhabdomyolysis and cardiac failure after receiving propofol for status epilepticus. The patient became symptomatic within 55 h after initiation of propofol infusion. The maximal infusion rate did not exceed 7.2 mg/kg/h, and propofol in excess of 5mg/kg/h was infused for less than 20 h. Preexisting antiepileptic medication may have exacerbated acidosis. Propofol infusion for the treatment of status epilepticus should be carefully weighted against its real risk to develop propofol infusion syndrome, and alternative agents such as benzodiazepines or barbiturates should be considered for first line therapy. If necessary, prolonged propofol infusion at high doses for the treatment of status epilepticus should be used with caution, and in all cases careful monitoring for rhabdomyolysis and acidosis must be performed.