Continuous spike-and-wave activity during slow-wave sleep: syndrome or EEG pattern?

Reduced thalamic volume is strongly associated with electrical status epilepticus in sleep

To identify the relationship between thalamic volume and electrical status epilepticus in sleep (ESES). We analyzed subcortical gray matter volumes in patients with an ESES pattern on their electroencephalographs. All magnetic resonance imaging scans were considered within normal limits. The patients were not receiving antiepileptic drug at the time of the MRI study. High resolution T1-weighted 3-dimensional MPRAGE scans were assessed for segmentation and quantitative volumetric analysis of the brain by using the "volBrain" method. After correcting for total brain volume, volumes were compared with a group of healthy controls (HCs) and patients with benign childhood epilepsy with centrotemporal spikes (BECTS). Fifteen patients with ESES, 15 patients with BECTS, and 30 HCs were included. The median age of the patients with ESES was 8.5 (range, 5.8-13) years, 8 (range, 5-14) years for the HCs, and 7.8 (range, 4-13.5) years for the patients with BECTS. The total relative thalamic volume was significantly lower in patients with ESES than in the healthy controls (0.87 ± 0.07 vs. 0.93 ± 0.03, p = 0.002), and in patients with ESES than in those with BECTS (0.87 ± 0.07 vs. 0.93 ± 0.03, p = 0.006). There was no significant difference the HCs and patients with BECTS (0.93 ± 0.03 vs. 0.93 ± 0.03, p = 0.999). Both right and left relative thalamic volumes were lower in patients with ESES than in HCs (right thalamus: 0.43 ± 0.04 vs. 0.46 ± 0.02, p = 0.003, left thalamus: 0.44 ± 0.03 vs. 0.47 ± 0.02, p = 0.002), in patients with ESES than in patients with BECTS (right thalamus: 0.43 ± 0.04 vs. 0.46 ± 0.01, p = 0.01, left thalamus: 0.43 ± 0.04 vs. 0.47 ± 0.01, p = 0.007); however, there was no significant difference between the HCs and patients with BECTS (right thalamus: 0.46 ± 0.02 vs. 0.46 ± 0.01, p = 0.999, left thalamus: 0.47 ± 0.02 vs. 0.47 ± 0.01, p = 0.999). This study highlights the association between thalamic involvement and ESES, even when not severe enough to cause a detectable lesion on visual interpretation of MRI.

Etiological assessment of status epilepticus

Status epilepticus (SE) is a potentially serious condition that can affect vital and functional prognosis and requires urgent treatment. Etiology is a determining factor in the patient's functional outcome and in almost half of all cases justifies specific treatment to stop progression. Therefore, identifying and addressing the cause of SE is a key priority in SE management. However, the etiology can be difficult to identify among acute and remote causes, which can also be multiple and interrelated. The most common etiologies are the discontinuation of antiepileptic medication in patients with a prior history of epilepsy, and acute brain aggression in cases of new onset SE (cerebrovascular pathologies are the most common). The list of remaining possible etiologies includes heterogeneous pathological contexts. Refractory SE and especially New-Onset Refractory Status Epilepticus (NORSE) lead to an extension of the etiological assessment in the search for encephalitis of autoimmune or infectious origin in adults and in children, as well as a genetic pathology in children in particular. This is an overview of current knowledge of SE etiologies and a pragmatic approach for carrying out an etiological assessment based on the following steps: - Which etiological orientation is identified according to the field and clinical presentation?; - Which etiologies to look for in an inaugural SE?; - Which first-line assessment should be carried out? The place of the biological, EEG and imaging assessment is discussed; - Which etiologies to look for in case of refractory SE?

[Epileptiform activity index for the evaluation of treatment efficacy in patients with epileptic encephalopathy]

Continuous spike and waves during sleep (CSWS) may lead to different cognitive, motor and behavioral symptoms. CSWS is characterized by an electroencephalography (EEG) pattern of electrical status epilepticus during sleep (ESES). The article reviews the main criteria of ESES, localization of EEG-changes and main EEG-patterns. An analysis of abnormal neuroimaging findings in patients with ESES was performed. The main pathophysiologic theories of ESES pattern formation are reviewed. ESES diagnosis is usually based on rough visual assessment of the number of spikes and waves, but other methods of assessment are also utilized, including spike-wave index (SWI), which is widely used in clinical practice. SWI reflects the percentage of sleep covered with spikes and waves. Two different strategies of SWI calculation are used, but none of them is officially validated. Moreover, there is no consensus on the period of sleep to be used for the calculation of SWI. The article presents a detailed review of calculation and utilization of SWI. It is concluded that further research is needed to develop an optimal algorithm of SWI calculation.

Personality profile and health-related quality of life in adults with previous continuous spike-waves during slow sleep syndrome

INTRODUCTION

Epilepsy with continuous spike-waves during slow sleep syndrome (CSWSS) is characterized by various seizure types, a characteristic EEG pattern and neuropsychological disorders. The main purpose of this study was to evaluate the long-term outcome of CSWSS occurred in childhood and to evaluate the variables that could influence the quality of social adaptation and the personality profile.

MATERIAL AND METHODS

This is a prospective study on 24 young adults with previous CSWSS (median age 24.5 yrs) who were enrolled between January and July 2011 at the G. Gaslini Children's Hospital, Genoa, Italy. Patients were divided into two groups: twelve with previous spike-wave index (SWI > 85%) defined as typical CSWSS (T-CSWSS) and twelve with previous SWI = 50-85% defined as atypical CSWSS (A-CSWSS). All the subjects were submitted to Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Psychological General Well-Being Index (PGWBI), and to a structured interview.

RESULTS

A correlation was observed with the severity of EEG abnormalities expressed by the SWI and outcome. The T-CSWSS group showed a significantly lower perceived well-being. Similarly in the T-CSWSS group the percentage of MMPI-2 clinical scales with T-scores ≥65 was higher than in the A-CSWSS group. Finally, a significant lower schooling in the T-CSWSS group was observed.

CONCLUSION

There seem to be two forms of the same disease, with similar onset and clinical evolution but a different outcome regarding the social and psychological conditions. The outcome of the social adaptation and of the personality consciousness was related with the severity of the EEG abnormalities: more favorable in patients with less intense SWI activity (A-CSWSS) compared those with a more severe EEG impairment (T-CSWSS).

Stimulus-induced transitions between spike-wave discharges and spindles with the modulation of thalamic reticular nucleus

It is believed that thalamic reticular nucleus (TRN) controls spindles and spike-wave discharges (SWD) in seizure or sleeping processes. The dynamical mechanisms of spatiotemporal evolutions between these two types of activity, however, are not well understood. In light of this, we first use a single-compartment thalamocortical neural field model to investigate the effects of TRN on occurrence of SWD and its transition. Results show that the increasing inhibition from TRN to specific relay nuclei (SRN) can lead to the transition of system from SWD to slow-wave oscillation. Specially, it is shown that stimulations applied in the cortical neuronal populations can also initiate the SWD and slow-wave oscillation from the resting states under the typical inhibitory intensity from TRN to SRN. Then, we expand into a 3-compartment coupled thalamocortical model network in linear and circular structures, respectively, to explore the spatiotemporal evolutions of wave states in different compartments. The main results are: (i) for the open-ended model network, SWD induced by stimulus in the first compartment can be transformed into sleep-like slow UP-DOWN and spindle states as it propagates into the downstream compartments; (ii) for the close-ended model network, weak stimulations performed in the first compartment can result in the consistent experimentally observed spindle oscillations in all three compartments; in contrast, stronger periodic single-pulse stimulations applied in the first compartment can induce periodic transitions between SWD and spindle oscillations. Detailed investigations reveal that multi-attractor coexistence mechanism composed of SWD, spindles and background state underlies these state evolutions. What's more, in order to demonstrate the state evolution stability with respect to the topological structures of neural network, we further expand the 3-compartment coupled network into 10-compartment coupled one, with linear and circular structures, and nearest-neighbor (NN) coupled network as well as its realization of small-world (SW) topology via random rewiring, respectively. Interestingly, for the cases of linear and circular connetivities, qualitatively similar results were obtained in addition to the more irregularity of firings. However, SWD can be eventually transformed into the consistent low-amplitude oscillations for both NN and SW networks. In particular, SWD evolves into the slow spindling oscillations and background tonic oscillations within the NN and SW network, respectively. Our modeling and simulation studies highlight the effect of network topology in the evolutions of SWD and spindling oscillations, which provides new insights into the mechanisms of cortical seizures development.

Neurobehavioral consequences of continuous spike and waves during slow sleep (CSWS) in a pediatric population: A pattern of developmental hindrance

INTRODUCTION

Continuous spike and waves during slow sleep (CSWS) is a typical EEG pattern defined as diffuse, bilateral and recently also unilateral or focal localization spike-wave occurring in slow sleep or non-rapid eye movement sleep. Literature results so far point out a progressive deterioration and decline of intellectual functioning in CSWS patients, i.e. a loss of previously normally acquired skills, as well as persistent neurobehavioral disorders, beyond seizure and EEG control. The objective of this study was to shed light on the neurobehavioral impact of CSWS and to identify the potential clinical risk factors for development.

METHODS

We conducted a retrospective study involving a series of 16 CSWS idiopathic patients age 3-16years, considering the entire duration of epilepsy from the onset to the outcome, i.e. remission of CSWS pattern. All patients were longitudinally assessed taking into account clinical (sex, age at onset, lateralization and localization of epileptiform abnormalities, spike wave index, number of antiepileptic drugs) and behavioral features. Intelligent Quotient (IQ) was measured in the whole sample, whereas visuo-spatial attention, visuo-motor skills, short term memory and academic abilities (reading and writing) were tested in 6 out of 16 patients.

RESULTS

Our results showed that the most vulnerable from an intellectual point of view were those children who had an early-onset of CSWS whereas those with later onset resulted less affected (p=0.004). Neuropsychological outcome was better than the behavioral one and the lexical-semantic route in reading and writing resulted more severely affected compared to the phonological route.

CONCLUSIONS

Cognitive deterioration is one but not the only consequence of CSWS. Especially with respect to verbal skills, CSWS is responsible of a pattern of consequences in terms of developmental hindrance, including slowing of development and stagnation, whereas deterioration is rare. Behavioral and academic problems tend to persist beyond epilepsy resolution.

Should We Treat Electroencephalographic Discharges in the Clinic or in the Intensive Care Unit, and if so When and How?

The important question that often emerges in the clinic is how aggressive the therapy for nonconvulsive status epilepticus and electrical status epilepticus in sleep ought to be and how continuous the discharges in each of these 2 entities should be before therapy is aimed at them. Additionally, as the use of electroencephalographic monitoring continues to expand to include the clinic and intensive care unit populations, it is important to identify epileptiform patterns that warrant identification and treatment. This review will present the state-of-the-art data and suggest algorithms to manage these conditions.

Syndrome of Electrical Status Epilepticus During Sleep: Epileptic Encephalopathy Related to Brain Development

BACKGROUND

Epileptic encephalopathy with electrical status epilepticus during sleep is an age-related and self-limited disorder. The present study analyzed the etiology, demographics, and pathogenesis of patients with electrical status epilepticus during sleep to provide information on the diagnosis and therapy of this syndrome.

METHODS

The etiologies of epileptic encephalopathy with electrical status epilepticus during sleep in patients admitted in Chinese People's Liberation Army General Hospital from 2009 to 2014 were retrospectively analyzed. Patients were classified into the genetic, structural-metabolic, and unknown groups according to the etiology. Demographics and clinical characteristics of all the patients were then analyzed and compared among groups.

RESULTS

The etiologies of epileptic encephalopathy with electrical status epilepticus during sleep in 75 patients mainly included benign childhood epilepsy with centrotemporal spikes, Landau-Kleffner syndrome, polymicrogyria, and migration disorders. Age at onset of epilepsy did not show a specific pattern, but age at onset of epileptic encephalopathy with electrical status epilepticus during sleep was concentrated at age 6-9 years. The mean age at onset of epilepsy in the genetic group was significantly older than that in the structural-metabolic group (P < 0.05). Age at onset of epileptic encephalopathy with electrical status epilepticus during sleep did not significantly differ between the two groups.

CONCLUSIONS

Electrical status epilepticus during sleep is an epileptic encephalopathy related to brain development and presents an age-dependent occurrence.

Thalamic abnormalities in children with continuous spike-wave during slow-wave sleep: An F-18-fluorodeoxyglucose positron emission tomography perspective

OBJECTIVE

Thalamic injury has been implicated in the development of continuous spike-wave during slow-wave sleep (CSWS) in children with epilepsy. We studied thalamic abnormalities in children with CSWS using F-18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging.

METHODS

Twenty-three patients (12 male; mean age 9 years) with CSWS and normal thalami on brain magnetic resonance imaging (MRI) underwent FDG-PET. Thalamic glucose metabolism, represented by standardized uptake value normalized to whole brain (nSUV, RT for right thalamus and LT for left thalamus), and its asymmetry--absolute asymmetry index (AAI): ¦(RT-LT)¦*100/[(RT+LT)/2]--was calculated. These values were compared with those from 10 normal healthy controls (five female; mean age 11.1 years).

RESULTS

Thalamic glucose metabolism was abnormal in 18 patients (78.3%). Thalamic nSUV was decreased (n = 6) or increased (n = 1) bilaterally in seven children without any asymmetry. Abnormal thalamic symmetry [AAI = 3.7-31.5% (0.8-3.3% in controls)] was seen in 11 children. Of these, six children had a unilateral thalamic metabolic abnormality (increased metabolism, n = 3 and decreased metabolism, n = 3), whereas 5 of 14 children had abnormal asymmetry index with bilaterally normal (n = 4) or increased (n = 1) thalamic metabolism. No clear association of thalamic metabolic abnormalities was seen with the stage of evolution of CSWS (prodromal, acute, or residual) or with the cortical FDG abnormalities.

SIGNIFICANCE

Functional thalamic abnormalities, both unilateral and bilateral, are frequently seen in patients with CSWS. FDG-PET is a sensitive and quantifiable modality to detect these changes.

Lack of Prominent Cognitive Regression in the Long-term Outcome of Patients Having Electrical Status Epilepticus During Sleep With Different Types of Epilepsy Syndromes

The purpose was to document 4 patients with different epilepsy syndromes, showing electrical status epilepticus during sleep (ESES), without marked cognitive and behavioral regression in the long-term follow-up. The mean age at onset of seizures was 8 years. Absences, myoclonic, focal motor, or generalized tonic - clonic seizures and drop attacks were the prominent seizure types. The neurological examination and neuroimaging findings revealed no abnormality. Focal epileptiform electroencephalographic (EEG) activity was seen in 3 cases, whereas generalized photosensitive epileptic discharges were detected in 1 patient with juvenile myoclonic epilepsy. Neuropsychological evaluations of all cases were within the normal range, and deterioration in mental status was not observed during their mean follow-up duration of 14 years. Our data support the view that ESES can emerge along with different types of childhood epilepsy syndromes, including idiopathic generalized epilepsies, and may not always be a poor prognostic factor.

Electrical status epilepticus during sleep: a study of 22 patients

OBJECTIVE

The aim of this study was to evaluate the clinical and imaging characteristics, treatment results, and prognosis of patients with electrical status epilepticus during sleep (ESES).

METHOD

A total of 22 patients with ESES pattern on EEG were retrospectively studied.

RESULTS

The first neurological symptoms were seen at a mean age of 4.4years. The first symptoms in 77% of the patients were seizures. Other symptoms were hyperactivity, restlessness, insomnia, disinhibition, autistic behavior, speech retardation and deterioration in school performance. Diagnosis of ESES was made at a mean age of 7.45years, approximately 3years after the first symptom. Magnetic resonance imaging (MRI) was abnormal in 36% of the patients. Single photon emission computed tomography (SPECT) showed focal hypoperfusion after resolution of ESES involving left temporoparietal and right posterior temporal areas in four patients including three with normal MRI, and one with periventricular leukomalacia without focal cortical lesion. First line treatment with valproic acid monotherapy was not effective. Electrical status epilepticus during sleep disappeared in 82% of the patients on clobazam and 70% of the patients on clonazepam in combination with valproic acid within a few months. Topiramate was not found to be effective. A significant decrease in intelligence quotient (IQ) scores was found in 66% of the patients compared to the baseline.

CONCLUSIONS

ESES should be considered in children with new onset behavioral, cognitive, and speech problems with or without seizures. The high frequency of focal seizures and focal findings on SPECT suggest a focal origin. Clonazepam and clobazam were most effective in our cohort.

Encephalopathy with Electrical Status Epilepticus in Slow Wave Sleep – a review with an emphasis on regional (perisylvian) aspects

Aim.The aim of this article is to review criticaly the Electrical Status Epilepticus in Slow Sleep (ESES) phenomenon from a neurophysiological mechanisms aspect as well as terminological and classification issues.

Methods.The review includes all the relevant papers published during the last 43 years on the subject of ESES and Continous Spike – Wave in Sleep (CSWS).These papers were identified in various large databases via the internet.

Rewiev and remarks.ESES/CSWS phenomena can be held as a common final pathway originating from different etiologies, including patients with early brain damage (probably involving thalamic structures), but also patients without structural pathology as in atypical evolution of idiopathic regional childhood hyperexcitability syndromes (with Rolandic epilepsy as a prototype). There are hints that genetic predisposition might be an important factor in the development of this process. The two large patient groups (lesional and non-lesional) show the same EEG evolution and encephalopathic cognitive consequences. The sleep EEG activation can be held as a common endophenotype. ESES represents an extreme sleep activation/potentiation of the local/regional interictal discharges, enhancing them in frequency, territorial extension, intra and trans-hemispherial propagation, synchrony and continuity. This process is most probably not identical with the development of bilateral spike-wave pattern in „generalized” epilepsies which involves primarily or secondarily the thalamocortical system as it had been explored by Gloor (1979) for idiopathic generalized rpilepsy and Steriade and Amzica (2003) for different types of generalized spike and wave discharges.

Conclusions and syndromological embedding of ESES.In an overwhelming majority of the investigated cases, the maps of the single discharges constituting sleep activation are identical; with focal/regional interictal spikes followed by slow closing wave, as it is seen in childhood regional age dependent hyperexcitability syndromes (prototype of the centro-temporal spikes of Rolandic epilepsy). The main mechanism of the developing cognitive impairment is most probably the consequence of interference with plastic function of slow wave sleep by obliterating synaptic decline during sleep. Presently, the consensus and co-operative research is highly obstacled by the terminological chaos, the controversial definitions and views around this still striking and enigmatic phenomenon.

Episodic epileptic verbal auditory agnosia in Landau Kleffner syndrome treated with combination diazepam and corticosteroids

We report 2 pediatric patients who presented initially with seizures followed by subacute language regression characterized by a verbal auditory agnosia. These previously normal children had no evidence of expressive aphasia during their symptomatic periods. Further, in both cases, auditory agnosia was associated with sleep-activated electroencephalographic (EEG) epileptiform activity, consistent with Landau-Kleffner syndrome. However, both cases are unique since the episodic auditory agnosia and sleep-activated EEG epileptiform activity rapidly responded to combination therapy with pulse benzodiazepine and corticosteroids. Further, in each case, recurrences were characterized by similar symptoms, EEG findings, and beneficial responses to the pulse benzodiazepine and corticosteroid therapy. These observations suggest that pulse combination high-dose corticosteroid and benzodiazepine therapy may be especially effective in Landau-Kleffner syndrome.

Efficacy of levetiracetam in electrical status epilepticus during sleep of children: a multicenter experience

BACKGROUND

Electrical status epilepticus during sleep is characterized by epilepsy, a specific electroencephalographic pattern, and neuropsychological impairment. This study aims to evaluate the efficacy and safety of levetiracetam in treating children with electrical status epilepticus during sleep.

METHODS

A multicenter, retrospective, open-label study enrolled 73 children (mean age: 8 years) affected by electrical status epilepticus during sleep. The efficacy was rated according to the seizure frequency and electroencephalography response.

RESULTS

After a mean treatment period of 19 months (range: 6 to 24 months), 33 (63.5%) of 52 patients became seizure-free or had experienced remarkable reduction in seizures. The electrical status epilepticus of 41 (56.2%) of 73 patients disappeared off their electroencephalography. The electroencephalography efficacy of levetiracetam treatment was noted in the monotherapy (61.9%) and add-on (53.9%) groups. The clinical (67.7%) and electroencephalography (64.3%) response rates of the idiopathic group were better than those of the symptomatic group (57.1% and 45.2%, respectively). No patient discontinued the trial because of intolerability of side effects.

CONCLUSIONS

Levetiracetam is effective in individuals with electrical status epilepticus during sleep with tolerable side effects.

Continuous Spikes and Waves during Sleep: Electroclinical Presentation and Suggestions for Management

Continuous spikes and waves during sleep (CSWS) is an epileptic encephalopathy characterized in most patients by (1) difficult to control seizures, (2) interictal epileptiform activity that becomes prominent during sleep leading to an electroencephalogram (EEG) pattern of electrical status epilepticus in sleep (ESES), and (3) neurocognitive regression. In this paper, we will summarize current epidemiological, clinical, and EEG knowledge on CSWS and will provide suggestions for treatment. CSWS typically presents with seizures around 2-4 years of age. Neurocognitive regression occurs around 5-6 years of age, and it is accompanied by subacute worsening of EEG abnormalities and seizures. At approximately 6-9 years of age, there is a gradual resolution of seizures and EEG abnormalities, but the neurocognitive deficits persist in most patients. The cause of CSWS is unknown, but early developmental lesions play a major role in approximately half of the patients, and genetic associations have recently been described. High-dose benzodiazepines and corticosteroids have been successfully used to treat clinical and electroencephalographic features. Corticosteroids are often reserved for refractory disease because of adverse events. Valproate, ethosuximide, levetiracetam, sulthiame, and lamotrigine have been also used with some success. Epilepsy surgery may be considered in a few selected patients.

Patients with electrical status epilepticus in sleep share similar clinical features regardless of their focal or generalized sleep potentiation of epileptiform activity

The study objective was to compare qualitatively the clinical features of patients with electrical status epilepticus in sleep with focal versus generalized sleep potentiated epileptiform activity. We enrolled patients 2 to 20 years of age, studied between 2001 and 2009, and with sleep potentiated epileptiform activity defined as an increase of epileptiform activity of 50% or more during non-rapid eye movement sleep compared with wakefulness. Eighty-five patients met the inclusion criteria, median age was 7.3 years, and 54 (63.5%) were boys. Sixty-seven (78.8%) patients had focal sleep potentiated epileptiform activity, whereas 18 (21.2%) had generalized sleep potentiated epileptiform activity. The 2 groups did not differ with respect to sex, age, presence of a structural brain abnormality, epilepsy, or other qualitative cognitive, motor, or behavioral problems. Our data suggest that there are no qualitative differences in the clinical features of patients with focal versus generalized sleep potentiated epileptiform activity.

Safety and efficacy of levetiracetam for the treatment of partial onset seizures in children from one month of age

Epilepsy is a common neurological disorder in the pediatric population, affecting up to one percent of children, and for which the mainstay of treatment is anticonvulsant medication. Despite the frequent use of anticonvulsant drugs, remarkably little is known about the safety and efficacy of most of these medications in the pediatric epilepsy population. Of 34 anticonvulsants currently approved for use by the US Food and Drug Administration (FDA), only 13 have been approved for use in children. Although infants and young children are disproportionately affected by epilepsy, there are currently only three anticonvulsant medications that have been specifically evaluated and approved for use in children younger than 2 years of age. In 2012, the FDA approved levetiracetam as an adjunctive treatment for partial onset seizures in infants and children from one month of age. Here we review the available data on levetiracetam in the pediatric epilepsy population. We first discuss the pharmacological profile of levetiracetam, including its mechanism of action, formulations and dosing, and pharmacokinetics in children. We then review the available efficacy, safety, and tolerability data in children from one month of age with partial onset seizures. We conclude that the current data leading to the approval of levetiracetam for use in infants and children with partial onset seizures is encouraging, although more work needs to be done before definitive conclusions can be drawn about the efficacy of levetiracetam across different pediatric age groups.

Electrical status epilepticus in sleep: clinical presentation and pathophysiology

Electrical status epilepticus in sleep involves an electroencephalographic pattern where interictal epileptiform activity is potentiated in the transition from wakefulness to sleep. Near-continuous spikes and waves that occupy a significant proportion of nonrapid eye movement sleep appear as a result of sleep-potentiated epileptiform activity. This electroencephalographic pattern appears in different electroclinical syndromes that present three common characteristics with different degrees of severity: seizures, sleep-potentiated epileptiform activity, and neuropsychologic regression. Continuous spikes and waves during sleep comprise the severest epileptic encephalopathy in the electroclinical spectrum. Landau-Kleffner syndrome presents with intermediate severity. Some "benign" pediatric focal epileptic syndromes represent the mildest end of this continuum. Based on published data, we provide a framework for clinical and electrical events. The underlying mechanisms leading to sleep potentiation of epileptiform activity in electrical status epilepticus in sleep are incompletely understood. A genetic basis or acquired early developmental insult may disrupt the normal maturation of neuronal networks. These factors may dynamically alter normal processes of brain development, leading to an age-related pattern of electroclinical expression of electrical status epilepticus in sleep.

Neuropsychiatric impairment in children with continuous spikes and waves during slow sleep: a long-term follow-up study

A long-term follow-up study was conducted in patients affected by Continuous Spikes and Waves during slow Sleep (CSWS) to evaluate the long-term outcomes. Twenty-five patients (19 males, 6 females), from 2 to 16 years of age (mean age 6 years±3 SD), affected by CSWS syndrome, as defined by the International League Against Epilepsy (ILAE, 1989), were enrolled and followed for 11 years (mean duration of follow-up: 3.9 years). At the time of the appearance of CSWS, one or more neuropsychiatric disorders were present in 96% of the patients, such as behavioral problems in 54%, mental retardation in 37.5%, learning disabilities in 33%, developmental coordination disorder in 17%, language disorder in 12.5%, and pervasive developmental disorder in 8%. During the follow-up, neuropsychiatric dysfunctions remained unaltered in 52% of the patients, worsened in 24%, and improved in only 24%. Our data confirm that CSWS may be associated with a broad spectrum of neuropsychiatric disorders and may promote their worsening over time. Moreover, the findings cannot be generalized to all cases of children with CSWS because most of the children in the subgroups with no change in outcome and worse outcome had symptomatic CSWS.

Epileptic encephalopathies (including severe epilepsy syndromes)

Epileptic encephalopathies represent a group of devastating epileptic disorders that appear early in life and are characterized by pharmacoresistant generalized or focal seizures, persistent severe electroencephalography (EEG) abnormalities, and cognitive dysfunction or decline. The ictal and interictal epileptic discharges are age-specific and are the main etiologic factors causing cognitive deterioration. This is most obvious in the idiopathic group. In the symptomatic group, the most common causes are structural, congenital, or acquired and rarely some metabolic disorders. In certain cases, clinical and EEG abnormalities persist and may evolve from one type to another as the child grows older. Various factors trigger and sustain the underlying pathophysiologic process and the ongoing epileptic and epileptiform activity during the most critical periods of brain maturation, perpetuating their deleterious effect on the brain. Immune-mediated mechanisms may have a role, suggested by certain encephalopathies responding to immune-modulating treatments and by the finding of various autoimmune antibodies. The chance of a better cognitive outcome improves with early diagnosis and treatment that is appropriate and effective. Current antiepileptic drugs are, in general, not effective: we urgently need new trials in this very special epileptic category. This article briefly reviews the most common epileptic encephalopathies and analyzes the most important clinical issues.

Epileptic Encephalopathies with Status Epilepticus during Sleep: New Techniques for Understanding Pathophysiology and Therapeutic Options

Encephalopathy with status epilepticus during sleep (ESES) is an epileptic encephalopathy, as defined by the International League Against Epilepsy (ILAE) Task Force on Classification and Terminology, that is, a condition in which the epileptic processes themselves are believed to contribute to the disturbance in cerebral function. Clinical manifestations of ESES are heterogeneous: apart from different seizure types, they consist in combinations of cognitive, motor, and behavioural disturbances associated with a peculiar electroencephalographic pattern of paroxysmal activity significantly activated during slow sleep, which culminates in a picture of continuous spikes and waves during sleep (CSWS). The pathophysiological mechanisms underlying this condition are still incompletely understood. Establishing a clear-cut correlation between EEG abnormalities and clinical data, though interesting, is very complex. Computer-assisted EEG analyses especially if combined with functional magnetic resonance imaging (EEG-fMRI) and metabolic neuroimaging have recently emerged as useful approaches to better understand the pathophysiological processes underlying ESES. Treatment of ESES is not just limited to seizures control but it should be focused on controlling neuropsychological outcome through an improvement of the continuous epileptiform activity. General agreement on treatment guidelines is still lacking. Implementation of new techniques might allow a better understanding of the pathophysiology of ESES and could enhance therapeutics options.

Early thalamic lesions in patients with sleep-potentiated epileptiform activity

OBJECTIVE

To compare the prevalence and type of early developmental lesions in patients with a clinical presentation consistent with electrical status epilepticus in sleep either with or without prominent sleep-potentiated epileptiform activity (PSPEA).

METHODS

We performed a case-control study and enrolled patients with 1) clinical features consistent with electrical status epilepticus in sleep, 2) ≥1 brain MRI scan, and 3) ≥1 overnight EEG recording. We quantified epileptiform activity using spike percentage, the percentage of 1-second bins in the EEG tracing containing at least 1 spike. PSPEA was present when spike percentage during non-REM sleep was ≥50% than spike percentage during wakefulness.

RESULTS

One hundred patients with PSPEA (cases) and 47 patients without PSPEA (controls) met the inclusion criteria during a 14-year period. Both groups were comparable in terms of clinical and epidemiologic features. Early developmental lesions were more frequent in cases (48% vs 19.2%, p = 0.002). Thalamic lesions were more frequent in cases (14% vs 2.1%, p = 0.037). The main types of early developmental lesions found in cases were vascular lesions (14%), periventricular leukomalacia (9%), and malformation of cortical development (5%). Vascular lesions were the only type of early developmental lesions that were more frequent in cases (14% vs 0%, p = 0.005).

CONCLUSIONS

Patients with PSPEA have a higher frequency of early developmental lesions and thalamic lesions than a comparable population of patients without PSPEA. Vascular lesions were the type of early developmental lesions most related to PSPEA.

Short-term response of sleep-potentiated spiking to high-dose diazepam in electric status epilepticus during sleep

We describe the short-term effects of high-dose oral diazepam on sleep-potentiated epileptiform activity in patients with electric status epilepticus during sleep. We enrolled patients treated with high-dose oral bedtime diazepam from 2001-2009. We defined spike percentage as the percentage of 1-second bins containing at least one spike, and calculated it during three randomly selected 5-minute samples of wakefulness throughout the day and during the first 5 minutes of every hour of non-rapid eye movement sleep at night. In this study, patients were considered to demonstrate sleep-potentiated epileptiform activity when their spike percentage during sleep was increased by ≥50% compared with wakefulness. Twenty-nine children (18 boys) were included (median age, 7.4 years). Twenty-four hours after receiving high-dose diazepam, epileptiform activity was significantly reduced (76.7% at baseline vs 40.8% 24 hours after high-dose diazepam; Wilcoxon signed ranks test, Z = -4.287, P < 0.0001). Seven patients (24.1%) manifested mild, reversible side effects during the first 48 hours after diazepam administration. High-dose oral diazepam effectively and safely reduced epileptiform activity in patients with electric status epilepticus during sleep.

Long-term outcome of 32 children with encephalopathy with status epilepticus during sleep, or ESES syndrome

PURPOSE

To prospectively evaluate the efficacy of drug treatment and long-term cognitive outcome in children with encephalopathy with status epilepticus during sleep (ESESS).

METHODS

Thirty-two children were diagnosed and prospectively followed up for at least 3 years at our unit between 1991 and 2007. Twenty-seven children were included in the prospective treatment study with valproate (VPA) and 17 with VPA combined with ethosuximide (ESM). Treatment response of disappearance of electrical status epilepticus during sleep (SES) was documented with overnight EEG recordings. Neuropsychological follow up for at least 5 years was available in 18 patients.

RESULTS

Six children had atypical rolandic (AR) epilepsy, nine Landau-Kleffner syndrome (LKS), and 17 symptomatic epilepsy. Before ESESS, 20 children were cognitively normal. Prospective treatment with VPA and ESM was effective in 3 of the 17 children (18%) treated. Abolition of SES with drug treatment was observed in 16 patients. In all, 10 children (31%), 4 with AR (67%), 3 with LKS (33%), and 3 with symptomatic etiology (19%), including 9 with treatment response regained the pre-ESESS cognitive level. Unfavorable cognitive outcome was predicted by younger age at ESESS diagnosis, lower IQ at the time of the diagnosis, and no response to drug treatment when compared with those with favorable cognitive outcome. Eight of the 16 nonresponders underwent epilepsy surgery.

DISCUSSION

Treatment response with VPA combined with ESM was observed more often than with other drug combinations. Most children with ESESS experienced permanent cognitive impairment. Cognitive outcome depends on treatment response on electroencephalography (EEG) and seizures, and on underlying etiology.

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.

Electrical status epilepticus in sleep

Electrical status epilepticus in sleep (ESES) describes an electroencephalographic pattern showing significant activation of epileptiform discharges in sleep. The terms continuous spike wave in slow-wave sleep (CSWS) and Landau-Kleffner syndrome (LKS) describe the clinical epileptic syndromes seen with ESES. Although there is an overlap between these 2 syndromes, children with CSWS present with a more global regression have more problematic epilepsy and have EEG foci located predominantly in frontotemporal or frontocentral regions. In contrast, children with LKS present with an acquired auditory agnosia, fewer seizures, and EEG foci in the posterotemporal regions. ESES requires a high degree of clinical suspicion because slow-wave sleep must be recorded to confirm this diagnosis. Treatment of ESES extends beyond just control of the seizures; amelioration of the continuous epileptiform discharge must occur to improve neuropsychological outcome. Although there is little evidence to guide treatment, conventional antiepileptic drugs play only a minimal role. Steroid therapy and high-dose benzodiazepines are most commonly used, but other therapies including intravenous gamma-globulin, the ketogenic diet, and surgical therapy with multiple subpial transaction have shown efficacy in small case series. Although epilepsy resolves with time in most cases, many children are left with significant cognitive or language impairment. Longer duration of ESES appears to be the major predictor of poor outcome; markedly abnormal neuronal activity during a critical period for synaptogenesis may result in aberrant synapse formation, explaining the poorer neuropsychological outcome. Early recognition and effective therapy are necessary to improve long-term prognosis in this condition.

Metabolic evidence for remote inhibition in epilepsies with continuous spike-waves during sleep

Epileptic syndromes with continuous spikes and waves during sleep (CSWS) are characterized by an acute phase with the emergence of psychomotor deficits and CSWS activity and by a recovery phase in which patients' clinical condition improves together with the remission of CSWS activity. The pathophysiological mechanisms of how CSWS activity induces psychomotor regression are still poorly understood. PET studies using [18F]-fluorodeoxyglucose (FDG) were performed in 9 children during acute and recovery phases of CSWS. PET data were analyzed at individual and group levels using statistical parametric mapping via subtractive, exclusive masking and variance analyses. Pathophysiological interaction analyses were conducted to determine the evolution of changes in effective connectivity between hypermetabolic and hypometabolic brain areas. At the individual level, CSWS recovery was characterized by a complete or almost complete regression of both hypermetabolic and hypometabolic abnormalities observed during the acute phase. Similar evolution was observed at the group level. Indeed, altered effective connectivity between focal hypermetabolism (centro-parietal regions and right fusiform gyrus) and widespread hypometabolism (prefrontal and orbitofrontal cortices, temporal lobes, left parietal cortex, precuneus and cerebellum) was found at the acute phase and markedly regressed at recovery. This study shows that the neurophysiological effects of CSWS activity are not restricted to the epileptic foci but spread via the inhibition of remote neurons within connected brain areas. The present study suggests that these reversible remote effects participate to the psychomotor repercussions of CSWS activity.

The spectrum of idiopathic Rolandic epilepsy syndromes and idiopathic occipital epilepsies: from the benign to the disabling

Benign childhood epilepsy with centrotemporal spikes (BCECTS) is an idiopathic focal epilepsy syndrome, the benign characteristics of which are debated; in fact, stable or intermittent specific neuropsychological deficits are frequent and may affect scholastic or adaptive abilities. Cognitive dysfunction may be related to a marked increment of the interictal epileptic discharges in NREM sleep: different degrees of neuropsychological deficits depend on the extent of awake and sleep activity and the predominant discharge localization. The age of onset and duration of atypical sleep EEG patterns may correlate with permanent cognitive impairments. These atypical clinical and EEG evolutions have been reported in the literature as different syndromes that constitute the spectrum of idiopathic rolandic epilepsy. Moreover, a clinical link between BCECTS and early-onset benign childhood occipital epilepsy has been demonstrated. According to the neurobiological approach, the spectrum of Idiopathic Rolandic Epilepsy is based on an age-dependent, idiopathic predisposition to focal seizures and sharp-wave discharges, as an expression of nonlesional cortical excitability. The involvement of a given area of the cerebral cortex may depend on the brain maturational stage.

Coexistence of Idiopathic Rolandic Epilepsy and CSWS in Two Families

PURPOSE

To report two families combining benign childhood epilepsy with centrotemporal spikes (BCECS) and cryptogenic epilepsy with continuous spike-waves during sleep (CSWS) in first-degree relatives.

METHODS

Clinical, EEG, and cerebral imaging data are described.

RESULTS

FAMILY 1: The proband was 3 years old at epilepsy onset. First seizures were convulsive, with centrotemporal spikes on EEG. At age 5 years, he had complex partial seizures, psychomotor regression, and centrotemporal CSWS. [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) showed left parietal hypermetabolism. After several antiepileptic drug (AED) trials, valproate (VPA) and ethosuximide (ESM) induced seizure remission, CSWS disappearance, and psychomotor improvement. Learning disabilities, however, persisted. Family history was remarkable for BCECS in his father. FAMILY 2: The proband was 2 years old at epilepsy onset. First seizures were convulsive, with centrotemporal CSWS on EEG. Despite several AED trials including corticosteroids, focal negative myoclonia, atypical absences, and psychomotor regression occurred, leading to severe mental retardation. FDG-PET showed bilateral parietal hypermetabolism. Vagus nerve stimulator was implanted. Her family history was remarkable for BCECS in her father and febrile convulsions in infancy in her mother.

CONCLUSIONS

These data suggest the existence of a common genetic basis between BCECS and cryptogenic epilepsies with CSWS. The higher expression in patients with CSWS could be related to other genetic or acquired factors. These data suggest that these epileptic syndromes constitute edges of a continuum.

Misleading effects of clonazepam in symptomatic electrical status epilepticus during sleep syndrome

Electrical status epilepticus during sleep syndrome and its variants are age-dependent epileptic encephalopathies associated with a sleep-related electroencephalographic pattern of continuous spike-waves, combined with motor or cognitive impairment. These epileptic encephalopathies are usually not responsive to conventional antiepileptic drugs. This report describes two children in whom clonazepam had no effect on cognitive and motor disorders but controlled spike activity, preventing a proper diagnosis. Withdrawal of clonazepam was accompanied by the recurrence of continuous spike-waves in slow sleep, permitting the diagnosis of electrical status epilepticus during sleep syndrome and appropriate therapeutic decisions. These two cases of the misleading effect of clonazepam in electrical status epilepticus during sleep syndrome illustrate the puzzling situation that can occur when therapeutic options only consider the electroencephalographic features without prior syndromic diagnosis.

Epilepsy in chromosomal abnormalities: an Italian sample

Epilepsy is common in chromosomal abnormalities, but systematic studies are scanty. We describe an Italian sample of patients with chromosomopathies to establish epilepsy occurrence and clinical electroencephalographic (EEG) features. Forty-five patients with different types of chromosomal abnormalities were analyzed to examine different variables in patients with epilepsy (group 1) and without (group 2) and to compare the types of epilepsy in our cases with respect to a nonselected sample of Italian people with epilepsy. Epilepsy occurred in 51.1% (group 1) of cases and prevailed in autosomal abnormalities but without a statistical significance (P > .05). There was a prevalence of EEG paroxysmal abnormalities in group 1 (P < .0001); continuous spike-waves during sleep were observed in three cases. Profound mental retardation prevailed in group 1 (P < .001) and mild mental retardation in group 2 (P < .05). Generalized epilepsies prevailed significantly (P < .00001). A high-resolution karyotype should be undertaken in all patients with epilepsy presenting with mental retardation when an obvious etiology is not available.

Anti-brain but not celiac disease antibodies in Landau-Kleffner Syndrome and related epilepsies

The Landau-Kleffner syndrome, the continuous spikes-waves during slow sleep syndrome and the benign epilepsy of childhood with rolandic spikes are rare childhood epilepsies with unknown etiology. Improvement in patients treated with immunoglobulin suggests an involvement of the immune system. We provide immunohistochemical evidence of autoantibodies against rat brain auditory cortex, brainstem and cerebellum, in children suffering with one or more of these syndromes. Only 1/14 patient was celiac.

Cognitive deterioration and electrical status epilepticus during slow sleep

The results of long-term follow-up of 10 children with global or specific cognitive deterioration and, on the electroencephalogram, electrical status epilepticus during sleep (ESES) are described. They were referred because of cognitive deterioration and underwent repeated neurological and neuropsychological examinations and all-night electroencephalography. A previous cognitive level was known or could be estimated in all. Seven children had a continuous spikes and waves during sleep (CSWS) syndrome, with global cognitive deterioration in four and more specific cognitive decline in three, and another three children had Landau-Kleffner syndrome (LKS). Of the last three, two children never had seizures, while the other had localization-related epilepsy. No children experienced aggravation of clinical seizures. However, therapy was disappointing. Cognitive dysfunction did not respond to valproate and/or benzodiazepines in 9 of the 10 children. A frontal epileptic focus was found in 5 of 7 children with CSWS, and a left temporal focus in 2 of 3 children with LKS. The ESES persisted in CSWS for 5-9 years and in LKS for 1-5 years, and disappeared at puberty. Good cognitive recovery after disappearance of ESES occurred in only one child, and partial recovery in four. An unfavorable prognosis of cognitive deterioration seems to be related to long-duration ESES and/or early onset epileptic activity. The authors are of the opinion that cognitive deterioration in children, with or without manifest epileptic seizures, should mandate electroencephalographic investigation during sleep.

Prise en charge des états de mal épileptiques de l'enfant épileptique

The treatment of status epilepticus (SE) in children with epilepsy depends on the epilepsy syndrome, in order to avoid worsening drugs such as IV barbiturates in severe myoclonic epilepsy in infancy (SMEI) (Dravet's syndrome) or IV benzodiazepam in tonic SE of Lennox-Gastaut syndrome. Intensive care procedures should not be systematical in convulsive SE (CSE) and are not indicated in non-convulsive SE (NCSE). Generalized CSE mostly involve SMEI before 3 years of age, symptomatic generalized epilepsy and partial lesional epilepsy. Treatment is an emergency and relies on IV benzodiazepines and, if necessary, IV phenytoine using plasmatic concentrations for an optimal management. The partial CSE of partial lesional epilepsy can result in focal deficit and need the same treatment as generalized CSE. NCSE consist in absence and/or myoclonic SE and are often unrecognised during a long time until EEG is performed. They mostly involve myoclonic epilepsies and can be controlled by IV benzodiazepines. The frequency of partial NCSE is underestimated, particularly in infants. Diagnosis relies on video EEG and treatment is the same as that used in partial CSE.

Efficacy of levetiracetam in pharmacoresistant continuous spikes and waves during slow sleep

OBJECTIVE

To evaluate the efficacy of levetiracetam (LEV) in continuous spikes and waves during slow sleep (CSWS). Despite first description dates back to 1971, no agreement exists about CSWS treatment. The condition is rare and controlled clinical trials are very difficult to perform, so the reports about efficacy of different drugs are anecdotal.

PATIENTS AND METHODS

We introduced LEV in three children affected by symptomatic focal epilepsy and pharmacoresistant CSWS and evaluated clinical, neuropsychological and electroencephalographic outcome.

RESULTS

Two cases responded completely, one case showed only a mild reduction of spikes and waves during slow sleep.

CONCLUSION

Even if our report is anecdotal, LEV expands the spectrum of antiepileptic drugs that can be used for the treatment of CSWS. LEV efficacy should be confirmed in larger series.

Seizures and epilepsy among children with language regression and autistic spectrum disorders

Clinical and subclinical seizures occur frequently among children with autistic spectrum disorders. Electrographic status epilepticus in sleep, or continuous spike-wave in slow-wave sleep, is a typical feature of acquired epileptic aphasia and Landau-Kleffner syndrome. Seizures and epilepsy are more common among children with autistic spectrum disorder who experience language regression, especially those who experience language regression after the age of 2 years. Although the seizures associated with Landau-Kleffner syndrome and with acquired epileptic aphasia can be easily treated, improvement in language function often does not follow successful treatment of seizures. There are no published randomized clinical trials of treatments for Landau-Kleffner syndrome or for autistic language regression. Broad-spectrum antiepileptic drugs not associated with cognitive slowing are probably the treatment of choice for epilepsy among children with autistic spectrum disorder. Large multisite trials are needed to determine treatment efficacy among children with Landau-Kleffner syndrome and acquired epileptic aphasia and to establish whether there is a cause-effect relationship between electrographic status epilepticus in sleep or continuous spike-wave in slow-wave sleep and autistic language regression.

Epileptic encephalopathies: a brief overview

Epileptic encephalopathies are conditions in which neurologic deterioration is attributable entirely or partly to epileptic activity. It can be due to very frequent or severe seizures and/or to subcontinuous paroxysmal interictal activity. The former mainly consists of Dravet syndrome, in which patients have seizures from the middle of the first year of life and repeat episodes of severe febrile status epilepticus and migrating partial epilepsy in infancy, in which from the first trimester of life, partial seizures affect various areas of the cortex randomly and in a subcontinuous fashion. In Rasmussen syndrome, also, epileptic activity contributes at least partly to the neurologic deterioration. Subcontinuous paroxysmal interictal activity affects newborn infants with suppression bursts, thus consisting in either Ohtahara syndrome or neonatal myoclonic encephalopathy. In infants, it is either myoclonic epilepsy of nonprogressive encephalopathy or West syndrome. In school-age children, it consists of various types of generalized seizures combined with slow spike waves of the Lennox-Gastaut syndrome, myoclonic-astatic epilepsy, and continuous spike waves in slow sleep combined with various motor or cognitive deficits including negative myoclonus, orofacial dyspraxia, Landau-Kleffner syndrome, and frontal lobe syndrome. Treatment differs for all of these syndromes. It is important to avoid potential drug-induced worsening, and valproate is preferred when a definitive diagnosis is not reached in children and especially infants.