Treatment with flunitrazepam of continuous spikes and waves during slow wave sleep (CSWS) in children.

We describe our treatment of two boys with continuous spikes and waves during slow wave sleep (CSWS). One of the boys was suffering from non-convulsive status epilepticus and the other from conscious disturbance with automatism. Their ictal EEG readings showed continuous diffuse spike and wave complexes, which were considered to show electrical status. The boys were diagnosed as having CSWS, and were later diagnosed with Landau-Kleffner syndrome (LKS). EEG readings returned to normal on intravenous injection of flunitazepam (FZP) at a dose of 0.02 mg/kg, suggesting that FZP is an effective treatment for CSWS.     

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.     

Scalp‐recorded high‐frequency oscillations in childhood sleep‐induced electrical status epilepticus

Because high‐frequency oscillations (HFOs) may affect normal brain functions, we examined them using electroencephalography (EEG) in epilepsy with continuous spike‐waves during slow‐wave sleep (CSWS), a condition that can cause neuropsychological regression. In 10 children between 6 and 9 years of age with epilepsy with CSWS or related disorders, we investigated HFOs in scalp EEG spikes during slow‐wave sleep through temporal expansion of the EEG traces with a low‐cut frequency filter at 70 Hz as well as through time‐frequency power spectral analysis. HFOs (ripples) concurrent with spikes were detected in the temporally expanded traces, and the frequency of the high‐frequency peak with the greatest power in each patient’s spectra ranged from 97.7 to 140.6 Hz. This is the first report on the detection of HFOs from scalp EEG recordings in epileptic patients. We speculate that epileptic HFOs may interfere with higher brain functions in epilepsy with CSWS.     

A patient with 22q13 deletion syndrome accompanied by epilepsy with continuous spike-waves during slow wave sleep (CSWS) and cerebral infarction

We describe a patient with 22q13 deletion syndrome accompanied by epilepsy with continuous spike-waves during slow wave sleep (CSWS). This patient showed central hypotonia, mental retardation, disappearance of language, multiple facial anomalies, and intractable epilepsy. Overnight EEG showed CSWS (spike & wave index = 99.2%) at seven years of age. Chromosomal analysis using G-banding revealed a deletion at the end of chromosome 22, indicative of 22q13 syndrome. In addition, subsequent magnetic resonance imaging (MRI) demonstrated cerebral infarction in the left posterior temporal area, which was probably caused by recurrent status epilepticus. Unlike previous case reports, a striking feature in this patient was the development of motor deterioration after 15 years of age. The severe EEG abnormalities and frequent status epilepticus might induce this deterioration and brain infarction.     

Encephalopathy with continuous spike‐waves during slow‐wave sleep: evolution and prognosis

Encephalopathy with continuous spike‐waves during slow‐wave sleep (CSWS) evolves over time, and three stages can be recognized: before the onset of CSWS, during CSWS, and after the CSWS period. Clinical seizures tend to remit spontaneously around puberty. This pattern is independent of the etiological lesion. The CSWS also disappears in all cases. Focal abnormalities instead, may persist for some time after the disappearance of CSWS. The disappearance of the clinical seizures and CSWS may be simultaneous or seizures may disappear before or after disappearance of the CSWS pattern on the EEG. Electroclinical parameters in the pre‐CSWS period that have been proposed to predict a poor outcome are early‐onset seizures, appearance of new seizures, and a significant increase in seizure frequency. From the electrical point of view, an increase in the frequency of the interictal EEG paroxysms while awake and during sleep and bilateral spike‐and‐wave paroxysms may also be predictive of a poor evolution in CSWS. When CSWS disappears, neurocognitive and behavioral status improve, but in most patients, residual moderate to severe neurocognitive impairments remain. In non‐lesional epilepsy, cognitive recovery after cessation of the CSWS depends on the severity and duration of the initial regression. The duration of the CSWS seems to be the most important predictor of cognitive outcome. Early recognition and effective therapy to reduce the seizures and resolve the CSWS may be crucial to improve long‐term prognosis. Cognitive recovery is observed in patients who respond well to AED treatment and outcome depends on the etiology.     

Acquired cognitive dysfunction with focal sleep spiking activity

The syndrome of continuous spike-waves during slow sleep (CSWS) is considered an epileptic encephalopathy in which the epileptiform abnormalities may contribute to progressive cognitive dysfunction. The characteristic electroencephalographic feature of the syndrome occurs during non-REM sleep, and takes the form of continuous bilateral and diffuse slow spike-waves that persist through all slow sleep stages. Using a case study design including clinical, neuropsychological, electroencephalographic, and positron emission tomography with 18F-fluorodeoxyglucose (PET-FDG) investigations, we describe the clinical and electroencephalographic findings in two patients who presented with nonsymptomatic epilepsy with unilateral spike-waves during sleep. Both patients presented with a left unilateral motor neglect of the upper limb that was associated with unilateral CSWS activity over the right hemisphere, predominantly in the centrotemporal region. PET-FDG studies during the active phase of CSWS showed right centrotemporal hypermetabolism in both cases. After treatment, a regression of the CSWS activity and an improvement of the cerebral FDG pattern were paralleled by a remission of the motor neglect. These cases demonstrate that the electroencephalographic pattern of CSWS in nonsymptomatic epilepsies is not necessarily diffuse and bilateral, and that focal unilateral CSWS activity can be associated with focal neuropsychological deficits. These findings add further evidence that the spectrum of clinical conditions associated with the electroencephalographic pattern of CSWS can include different forms of acquired cognitive disturbances that may be focal in nature.     

The ketogenic diet can be used successfully in combination with corticosteroids for epileptic encephalopathies

Hormonal therapy or ketogenic diet often permits overcoming the challenging periods of many epileptic encephalopathies (West and Lennox–Gastaut syndromes and encephalopathy with continuous spike–waves in slow sleep), but relapse affects over 20% of patients. We report here a monocenter pilot series of 42 consecutive patients in whom we combined oral steroids with the ketogenic diet for corticosteroid-resistant or -dependent epileptic encephalopathy. We retrospectively evaluated the effect on seizure frequency, interictal spike activity, neuropsychological course, and steroid treatment course.Twenty-three patients had West syndrome (WS), 13 had encephalopathy with continuous spike–waves in slow sleep (CSWS), and six others had miscellaneous epileptic encephalopathies. All patients succeeded to reach 0.8 to 1.6 g/l ketone bodies in the urine following the usual KD regimen. For at least 6 months, 14/42 responded to the addition of the ketogenic diet: 4/23 with WS, 8/13 with CSWS, and 2/6 with miscellaneous epileptic encephalopathies. The addition of the KD allowed withdrawing steroids in all responders. Among them, 10/15 had been patients with steroid-dependent epileptic encephalopathy and 4/27 patients with steroid-resistant epileptic encephalopathy.Therefore, the ketogenic diet can be used successfully in combination with corticosteroids for epileptic encephalopathies. Patients presenting with steroid-dependent CSWS seem to be the best candidates.     

Continuous spikes and waves during slow sleep in an adult

Continuous spikes and waves during slow wave sleep (CSWS) is rare and is considered to be an age-related epileptic syndrome occurring only in children. We report the case of a 21-year-old patient diagnosed with this syndrome. The patient had a history of seizures since the age of 3 and was admitted for continuous video/EEG monitoring to evaluate seizure exacerbation and unprovoked outbursts of anger. During 3 days of monitoring, awake EEG recordings showed focal slow wave activity in the right temporal region. CSWS were observed. After a change in his antiepileptic drug regimen, subsequent EEG recordings showed resolution of CSWS. As shown in our patient, CSWS can be observed in adults. In addition, continuous video/EEG monitoring including sleep is important in the evaluation of patients with sudden deterioration of seizure control accompanied by behavioral changes.     

Epileptic encephalopathy of late childhood: Landau-Kleffner syndrome and the syndrome of continuous spikes and waves during slow-wave sleep.

Landau-Kleffner syndrome (LKS) and the syndrome of continuous spikes and waves during slow wave sleep (CSWS) are two points on the spectrum of functional childhood epileptic encephalopathies. They are characterized by a severe paroxysmal EEG disturbance that may permanently alter the critical synaptogenesis by strengthening synaptic contacts that should have been naturally "pruned." The much more common benign epilepsy with centrotemporal spikes is also related to LKS and CSWS by a common pathophysiology. Although prognosis in LKS and CSWS for seizure control is good, cognitive function declines and permanent neuropsychologic dysfunction is seen in many cases. This permanent damage is most evident in those patients who had early-onset EEG abnormality and a prolonged active phase of continuous spike-and-wave discharges during sleep. If the active phase of paroxysmal activity persists for over 2 to 3 years, even successful treatment does not resolve neuropsychologic sequelae. In LKS, the paroxysmal activity permanently affects the posterior temporal area and results in auditory agnosia and language deficits; in CSWS, the frontal lobes are more involved and other cognitive disturbances predominate. Aggressive treatment should include high-dose antiepileptic drugs, corticosteroids, and surgery in specific cases.     

Encephalopathy related to status epilepticus during slow sleep (ESES) as atypical evolution of Panayiotopoulos syndrome: an EEG and neuropsychological study

Aim: We report two patients with Panayiotopoulos syndrome (PS) who developed encephalopathy related to status epilepticus during slow sleep (ESES) at the peak of their clinical course. Methods: Clinical charts and EEG data were reviewed. Results: The patients exhibited nocturnal autonomic seizures and occipital EEG foci, the latter of which later evolved into multifocal EEG foci with synchronous frontopolar and occipital spikes (Fp‐O EEG foci), and finally into continuous spikes‐waves during sleep (CSWS; spike‐wave index >85% based on whole‐night sleep recording) at eight years and seven years of age, respectively. The occipital spikes always preceded frontopolar spikes by 30～50 mseconds based on the analysis of CSWS. Neuropsychological ability, including IQ, deteriorated during the CSWS period in both patients. The autonomic seizures and focal to bilateral tonic‐clonic seizures were initially resistant to antiepileptic drugs (AEDs), and occurred more than 10 times in both patients. However, the seizures and EEG findings gradually resolved, and AEDs were successfully terminated in both patients. Conclusion: PS can progress to ESES if the clinical course exhibits atypical evolution. The initial autonomic symptom of the seizures and interictal Fp‐O EEG foci should be carefully monitored in patients with CSWS or ESES.     

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

IntroductionContinuous 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.MethodsWe conducted a retrospective study involving a series of 16 CSWS idiopathic patients age 3–16 years, 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.ResultsOur 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.ConclusionsCognitive 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.     

The spectrum of neuropsychiatric abnormalities associated with electrical status epilepticus in sleep

Electrical status epilepticus in sleep (ESES) is an electrographic pattern consisting of an almost continuous presence of spike-wave discharges in slow wave sleep. ESES is frequently encountered in pediatric syndromes associated with epilepsy or cognitive and language dysfunction. It can be present in various evolutionary stages of a spectrum of diseases, the prototypes of which are the 'continuous spikes and waves during slow wave sleep' syndrome (CSWS), the Landau-Kleffner syndrome (LKS), as well as in patients initially presenting as benign childhood epilepsy with centrotemporal spikes (BECTS). The purpose of this article is to review the literature data on the semiology, electrographic findings, prognosis, therapeutic options, as well as the current theories on the pathophysiology of these disorders. The frequent overlap of CSWS, LKS, and BECTS urges an increased level of awareness for the occasional transition from benign conditions such as BECTS to more devastating syndromes such as LKS and CSWS. Identification of atypical signs and symptoms, such as high discharge rates, prolonged duration of ESES, neuropsychiatric and cognitive dysfunction, lack of responsiveness to medications, and pre-existing neurologic conditions is of paramount importance in order to initiate the appropriate diagnostic measures. Prolonged and if needed repetitive sleep electroencephalographs (EEGs) are warranted for proper diagnosis.     

Early thalamic injury associated with epilepsy and continuous spike-wave during slow sleep

PURPOSE: Mechanisms inducing continuous spike-wave during slow sleep (CSWS) in encephalopathy with electrical status epilepticus during sleep are still unclear. Recently, some sporadic cases with early thalamic injury associated with CSWS have been reported. The aim of the study was to investigate in a population of patients with an early thalamic injury the presence of an activation of paroxysmal activities during sleep, their characteristics, and possible relations to neuroimaging and neuropsychological features. METHODS: Thirty-two patients with prenatal or perinatal thalamic injuries, mostly due to a vascular mechanisms, were fully examined, including neuroimaging, EEG monitoring, and cognitive follow-up. RESULTS AND CONCLUSIONS: Twenty-nine of 32 patients showed major sleep EEG activation. Among these 29 patients, two different groups were distinguished: the first included the more or less typical CSWS (12 cases), generally with symmetry of spike and waves (SWs) and often with no spindle at all. The other cases had an usual asymmetry of SWs and presence or reduction of spindles, plus other atypical features concerning synchronism and morphology of SWs. Behavioral disorders were significantly more present in patients with a true CSWS; their improvement (and in one case of the three thoroughly followed the improvement of cognitive competence) paralleled the disappearance of CSWS. The generally predominant injury of the lateral aspect of the thalamus included reticular nucleus and ventral nuclei. An imbalance of gamma-aminobutyric acid (GABA)(B)--versus GABA(A)--mediated receptors may be evoked as a cofactor predisposing to CSWS.     

Congenital hydrocephalus and continuous spike wave in slow-wave sleep--a common association?

Early-onset hydrocephalus was identified as the common denominator in 5 of 12 consecutive patients with Landau-Kleffner syndrome or continuous spike wave in slow-wave sleep who presented during the last 6 years. This association seems to be more common than expected, and the course of epileptic disease and outcome differs from that of previous reports. We present the clinical cases and discuss the possible connection between early hydrocephalus and epilepsy, especially continuous spike wave in slow-wave sleep. A retrospective analysis was undertaken of the clinical course and electroencephalographic (EEG) data before and after the development of continuous spike wave in slow-wave sleep in a group of five children with early-onset hydrocephalus identified in three epilepsy clinics in Israel. Landau-Kleffner syndrome or continuous spike wave in slow-wave sleep was identified in 12 patients during 6 years (1995-2000). Five patients had a history of early-onset hydrocephalus. Three patients had ventriculoperitoneal shunts; two of them were never shunted. Patients' seizures and continuous spike wave in slow-wave sleep epileptiform activity was resistant to appropriate anticonvulsant treatment. Pediatric neurologists and neurosurgeons should be aware of the association between continuous spike wave in slow-wave sleep and early-onset hydrocephalus. When a child with hydrocephalus presents with behavioral, cognitive, or motor deterioration, he or she should undergo sleep EEG in addition to investigation of shunt function. Our series demonstrated the presence of continuous spike wave in slow-wave sleep and localization-related epilepsy that did not originate from the shunt site. This group of patients is heterogeneous, and the exact trigger for continuous spike wave in slow-wave sleep development is still unclear.     

Motor impairment on awakening in a patient with an EEG pattern of "unilateral, continuous spikes and waves during slow sleep".

Movement disorders are rarely described in association with the "continuous spikes and waves during slow sleep (CSWS)" EEG pattern. We report the case of a young girl affected by an epileptic encephalopathy who, from the age of seven years and four months, has twice presented a movement disorder affecting the right arm, manifesting on awakening and disappearing by early afternoon. Sleep EEG during these periods showed continuous, high-amplitude, diphasic spikes and slow waves over the left hemisphere. Association of clobazam, valproic acid and, on the second occasion, ethosuccimide led to disappearance of the above-described EEG picture and associated motor symptoms. Neurophysiological investigations excluded other possible aetiologies. In view of this, and of the close relationship between the EEG picture and clinical course, we interpret the patient's impairment as "motor neglect" secondary to the continuous electrical activity recorded during sleep over the left hemisphere and involving the associative areas. This electrical activity in sleep, may be regarded as a "functional lesion" whose clinical consequences can be correlated with the site of the abnormalities.[Published with video sequences].     

CSWS-related autistic regression versus autistic regression without CSWS

Continuous spike-waves during slow-wave sleep (CSWS) and Landau-Kleffner syndrome (LKS) are two clinical epileptic syndromes that are associated with the electroencephalography (EEG) pattern of electrical status epilepticus during slow wave sleep (ESES). Autistic regression occurs in approximately 30% of children with autism and is associated with an epileptiform EEG in approximately 20%. The behavioral phenotypes of CSWS, LKS, and autistic regression overlap. However, the differences in age of regression, degree and type of regression, and frequency of epilepsy and EEG abnormalities suggest that these are distinct phenotypes. CSWS with autistic regression is rare, as is autistic regression associated with ESES. The pathophysiology and as such the treatment implications for children with CSWS and autistic regression are distinct from those with autistic regression without CSWS.     

Long-term outcome after cognitive and behavioral regression in nonlesional epilepsy with continuous spike-waves during slow-wave sleep

Purpose: To present the long‐term follow‐up of 10 adolescents and young adults with documented cognitive and behavioral regression as children due to nonlesional focal, mainly frontal, epilepsy with continuous spike‐waves during slow wave sleep (CSWS). Methods: Past medical and electroencephalography (EEG) data were reviewed and neuropsychological tests exploring main cognitive functions were administered. Key Findings: After a mean duration of follow‐up of 15.6 years (range, 8–23 years), none of the 10 patients had recovered fully, but four regained borderline to normal intelligence and were almost independent. Patients with prolonged global intellectual regression had the worst outcome, whereas those with more specific and short‐lived deficits recovered best. The marked behavioral disorders resolved in all but one patient. Executive functions were neither severely nor homogenously affected. Three patients with a frontal syndrome during the active phase (AP) disclosed only mild residual executive and social cognition deficits. The main cognitive gains occurred shortly after the AP, but qualitative improvements continued to occur. Long‐term outcome correlated best with duration of CSWS. Significance: Our findings emphasize that cognitive recovery after cessation of CSWS depends on the severity and duration of the initial regression. None of our patients had major executive and social cognition deficits with preserved intelligence, as reported in adults with early destructive lesions of the frontal lobes. Early recognition of epilepsy with CSWS and rapid introduction of effective therapy are crucial for a best possible outcome.     

Is sleep-related consolidation impaired in focal idiopathic epilepsies of childhood? A pilot study

We investigated sleep-related declarative memory consolidation in four children with focal idiopathic epilepsy. In a population of healthy control children, recall of learned pairs of words was increased after a night of sleep, but not after a daytime wakefulness period. In children with epilepsy (1 case of benign epilepsy with centro-temporal spikes, 1 case of benign childhood epilepsy with occipital paroxysms, and 2 cases of epileptic encephalopathy (EE) with continuous spike and waves during slow-wave sleep, CSWS), recall performance significantly decreased overnight, suggesting impairment in sleep-related declarative memory consolidation. Hydrocortisone treatment in one patient with EE with CSWS resulted in normalization of the sleep EEG together with normalization of overnight memory performance, which was not the case in the other EE/CSWS patient whose sleep EEG was only partially improved. These preliminary results suggest that interictal epileptiform discharges in idiopathic focal epilepsies may disrupt the brain processes underlying sleep-related memory consolidation.