Sulthiame add-on therapy in children with focal epilepsies associated with encephalopathy related to electrical status epilepticus during slow sleep (ESES)

Purpose: In children with symptomatic or idiopathic focal epilepsies, their disease may evolve into an epileptic encephalopathy related to continuous spike and wave during slow sleep (CSWS) or electrical status epilepticus during slow sleep (ESES). ESES syndrome implies serious risks of neuropsychologic impairment, and its treatment has frequently been disappointing. The aim of this study is to present our experience using sulthiame as add‐on treatment in 53 patients with ESES syndrome that was refractory to other antiepileptic drugs (AEDs). Methods: Neurologic examinations, cerebral magnetic resonance imaging (MRI), and repeated prolonged sleep electroencephalography (EEG) studies were performed in all cases. Data about school achievements and or neuropsychological evaluations were obtained repeatedly during the follow‐up of 1.5–16 years. Sulthiame was added in doses ranging between 5 and 30 mg/kg/day. Key Findings: Since add‐on of sulthiame, 10 of 28 patients in the symptomatic group became seizure free: 4 patients with normal EEG studies and 6 with residual spikes. Nine of 28 patients showed a significant reduction in number of seizures and presented spikes but no ESES on EEG. The other nine cases showed neither clinical nor EEG improvement. A striking result was that 3 of 11 children with unilateral polymicrogyria and ESES syndrome became seizure free, and in another six a significant improvement in frequency of seizures and in EEG abnormalities seemed to be related to the add‐on of sulthiame. Twenty‐one of the 25 patients in the idiopathic group became seizure free and without ESES in <3 months after add on of sulthiame. In two of the patients the changes were seen in a few days. Significance: We understand that sulthiame may be effective as add‐on treatment in children with ESES syndrome.     

Electrical status epilepticus in sleep (ESES)/continuous spikes and waves during slow sleep (CSWS) syndrome in children: An electroclinical evaluation according to the EEG patterns

ObjectiveThe aim of this study was to describe the electroclinical spectrum in children with electrical status epilepticus in sleep (ESES)/continuous spikes and waves during slow sleep (CSWS) syndrome according to the EEG patterns.MethodsClinical data of 44 patients with ESES/CSWS syndrome who were treated and followed at least two years were analyzed. Records of EEGs of patients were reevaluated to determine two aspects of the ESES pattern: (1) the spike–wave index (SWI) on the NREM sleep EEG (Group I: typical vs. atypical ESES pattern (33/11 patients)) and (2) the area of maximum amplitude of continuous epileptic activity (Group II: anterior vs. posterior ESES pattern (33/11 patients)).ResultsSymptomatic etiology was more defined in patients with the typical ESES pattern (40%) than the group with the atypical ESES pattern (9%) by a factor of four. All patients were receiving at least two antiepileptic drug (AED) treatments. Eighteen patients (41%) received AEDs plus ACTH therapy. Complete disappearance of the ESES pattern on the EEG was observed in 18 patients (41%), more than 50% reduction was observed in five patients (11%), less than 50% reduction was observed in eight patients (18%), and no response was observed in five patients (11%). No significant difference was found when comparing the groups in terms of reduction of seizures and the SWI. Seizure outcome at the two-year follow-up was similar between the group with ESES treated with AEDs plus ACTH and the group with ESES treated with AEDs without ACTH therapy.SignificanceThis study demonstrated that the rate of the SWI (typical vs. atypical ESES) and the maximum amplitude of the ESES pattern (anterior vs. posterior) have no significant correlation with seizure control and reduction of the SWI on the EEG in children with ESES syndrome.     

Abstracts of the 38th Congress of the Japan Epilepsy Society, Shizuoka, Japan, September 30-October 1, 2004

Diagnosis and Treatment of Idiopathic Focal Epilepsies (Benign Partial Epilepsies) in Infancy and Childhood. ¹ Tamiko Negoro ( ¹ Department of Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan ). Introduction: According to the revised classification of epilepsies and epileptic syndromes proposed by the Commission on Classification and Terminology of the International League Against Epilepsy (1989), benign childhood epilepsy with centrotemporal spikes (BCECT), childhood epilepsy with occipital paroxysms (Gastaut‐type late‐onset CEOP), and primary reading epilepsy were included in the idiopathic localization‐related epilepsies (ILRE). Since then, new epileptic syndromes such as Panayiotopoulos‐type early‐onset benign childhood occipital epilepsy (also known as benign childhood epilepsy with occipital paroxysms or BCEOP) and benign partial epilepsies in infancy (BPEI) have been additionally included as ILRE. The diagnostic criteria for benign partial epilepsies include (1) normal neurological examination; (2) normal intelligence; (3) normal neuroimaging; (4) a family history of benign‐type seizures; (5) brief stereotyped seizures; (6) frequent nocturnal occurrence; (7) easy control with antiepileptic drugs (AEDs), except ethosuximide; and (8) remission before adolescence. The EEG features include (1) normal background activity; (2) spikes with a characteristic morphology and location; (3) sleep activation; and (4) occasional generalized paroxysms. In our 114 cases of childhood onset localization‐related epilepsies (LRE) diagnosed between 1997 and 2000, 48 cases (42%) were diagnosed as ILRE and 66 were cryptogenic or symptomatic LRE. Among the 48 ILRE cases, 28 (58%) were classified as BCECT, six (13%) as BPEI, five (10%) as BCEOP, two (4%) as atypical benign partial epilepsy, and seven (15%) as unclassified. Carbamazepine (CBZ), valproate (VPA) and clonazepam (CZP) were equally effective in controlling the seizures in our ILRE patients. This review describes briefly the diagnosis and treatment of BCECT, BCEOP, and BPEI. Benign Childhood Epilepsy with Centrotemporal Spikes: BCECT is the most common ILRE (also known as idiopathic focal epilepsies) in infancy and childhood. Sylvian seizures (simple partial seizures or focal motor or sensory seizures beginning unilaterally at the lower part of the face) and EEG findings (central‐midtemporal high‐amplitude, repetitive sharp waves) are quite stereotyped, and diagnosis of typical cases is relatively easy. Frontal lobe seizures with bilateral perioral twitches or unilateral eyelid twitches may sometimes be misdiagnosed as Sylvian seizures. Since status epilepticus is very rare and many patients only have occasional seizures, many physicians choose not to treat the disorder. If treatment is necessary, the seizures are usually easily controlled with carbamazepine, valproic acid, or clonazepam. Continuation of AEDs is not necessary after the EEG has normalized around puberty. The prognosis is excellent. However, a small percentage of patients may show atypical evolutions such as atypical benign partial epilepsy, epilepsy with continuous spike‐and‐waves in slow wave sleep, or epilepsy with centrotemporal spikes and oromotor deficit. Seizure and EEG exacerbations by AEDs, especially carbamazepine, have to be considered. Early recognition and proper treatment are necessary for these conditions. Benign Childhood Epilepsy with Occipital Paroxysms: BCEOP is also known as Panayiotopoulos‐type early‐onset benign childhood occipital epilepsy. The mean age at first seizure is around 5 years. Seizures comprise an unusual constellation of autonomic, mainly emetic, syndromes with unilateral deviation of the eyes and impairment of consciousness. Visual symptoms, which are the main symptoms in Gastaut‐type, late‐onset CEOP, are exceptions in BCEOP. According to our 41 cases examined between 1984 and 1993, two‐thirds of the patients show hemi‐ or generalized convulsions and one‐fourth experience prolonged seizures for longer than 30 minutes. EEG findings (bilateral occipital paroxysms) consist of some extraoccipital abnormalities especially in the frontal area (48% of our cases) or generalized paroxysmal discharges (32% of ours cases), together with various migrations of spike foci. EEG findings seem to normalize around the age of 10 years. Many patients only have occasional seizures and these seizures are usually easy to control with carbamazepine or valproic acid. The prognosis is excellent. Prevention of status epilepticus is the major problem in this disorder. Recently, new concepts including early‐onset benign occipital seizure susceptibility syndrome (EBOSS) and Panayiotopoulos syndrome (idiopathic susceptibility to early‐onset benign childhood seizures with mainly autonomic symptoms), have been introduced for BCEOP. Benign Partial Epilepsies in Infancy: BPEI comprise two forms. One is partial epilepsy with complex partial seizures (CPS) and the other is partial epilepsy with secondarily generalized seizures (SGS). Onset is mostly during the first year of life. Seizures often occur in clusters and are characterized by motion arrest, decreased responsiveness, staring or blank eyes often with automatisms, and mild convulsive movements in the CPS form; and motion arrest or opening of eyes with staring or blank eyes followed by generalized tonic–clonic seizures in the SGS form. Interictal EEGs mostly show no abnormal findings. According to the ictal EEGs, the most frequent site of seizure origin is in the frontal or temporal area in the CPS form; and central, parietal, or occipital area in the SGS form. Treatment with carbamazepine, phenobarbital, zonisamide or valproic acid immediately stops the cluster of seizures. The prognosis is excellent. Recently, sleep‐related and low‐voltage Rolandic and vertex spikes have been reported as an EEG marker of benignity in this disorder. Most of benign infantile convulsions may belong to partial epilepsy with SGS, although confirmation with ictal EEG recording is necessary for accurate diagnosis.     

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.     

Panayiotopoulos syndrome and symptomatic occipital lobe epilepsy of childhood: a clinical and EEG study

Aim. Panayiotopoulos syndrome (PS) is an age‐related seizure susceptibility syndrome that affects the central autonomic system. Although the majority of the few ictal recordings obtained so far suggest an occipital origin, semiological and interictal EEG data appear to favour more extensive involvement. In this study, the characteristics (including those based on semiology and EEG) of children with Panayiotopoulos syndrome (n=24) and those with lesion‐related, symptomatic occipital lobe epilepsy (SOLE) (n=23) were compared. Methods. Detailed semiological information and EEG parameters including the localisation, distribution, density (n/sec), reactivity, and morphological characteristics of spike‐wave foci and their relationship with different states of vigilance were compared between the two groups. Results. The age at seizure onset was significantly younger in patients with symptomatic occipital lobe epilepsy than in those with PS (mean age at onset: 3.4 versus 5.6 years, respectively; p=0.044). Autonomic seizures (p=0.001) and ictal syncope (p=0.055) were more frequent in PS than in symptomatic occipital lobe epilepsy (87.5% and 37.5% versus 43.5% and 13%, respectively). The interictal spike‐wave activity increased significantly during non‐rapid eye movement (non‐REM) sleep in both groups. The spike waves in non‐REM seen in PS tended to spread mainly to central and centro‐temporal regions. Conclusions. The results indicate that although common features do exist, Panayiotopoulos syndrome differs from symptomatic occipital lobe epilepsy and has a unique low epileptogenic threshold related to particular brain circuits.     

A review of the relationships between Landau-Kleffner syndrome, electrical status epilepticus during sleep, and continuous spike-waves during sleep

The goal of this report is to review the relationships between Landau-Kleffner syndrome (LKS), electrical status epilepticus during sleep (ESES), and continuous spike-waves during sleep (CSWS). LKS is a clinical syndrome involving mainly acquired aphasia and sometimes seizures. Other clinical findings include cognitive impairments and global regression of behavior. The EEG may evolve from more benign conditions into ESES (or CSWS), seen in 50% of patients with LKS, or may also show focal findings. Seizures include atypical absence, generalized tonic-clonic, atonic, and partial motor attacks. Effective medications are discussed. The EEG patterns CSWS and ESES are likely equivalent terms. CSWS is used by some authors, and ESES by others. Patients with these patterns usually show mental retardation, seizures, and global regression. More benign EEG patterns, like focal discharges, may develop into these more severe generalized patterns, which are associated with atypical absences, negative myoclonus, and cognitive disturbances. Memory disorders are common, because the nearly continuous generalized discharges in sleep do not allow for the memory consolidation that also occurs during sleep. Medications and possible etiologies are discussed.     

EEG in children with early-onset benign occipital seizure susceptibility syndrome: Panayiotopoulos syndrome

PURPOSE: We analyzed sequential changes in the localization of EEG foci along with age to identify a specific EEG pattern, and the relation between the clinical manifestations and the EEG pattern in patients with Panayiotopoulos syndrome (PS). METHODS: The subjects were 76 children, who had been followed up >2 years with repeated EEG examinations at 6-month intervals. Analysis of EEG findings included the determination of localization of spike foci, as a function of age, by using cross-sectional data, and the identification of subgroups with homogeneous EEG patterns. Then we compared certain clinical features among these subgroups. RESULTS: In the cross-sectional EEG study, the occipital EEG spike focus was most frequently seen between ages 2 and 5 years. Independent and synchronous frontopolar and occipital spikes (Fp-O spikes) and centroparietotemporal (CPT) EEG spike foci had increased incidences between ages 4 and 7 years, and between ages 6 and 10 years, respectively. We subclassified the 76 patients into the following five subgroups based on the evolutional changes in epileptic EEG foci, which frequently showed shifting, multiplications, and generalization: (a) persistent occipital focus group (O group), (b) Fp-O spikes group (Fp-O pattern group), (c) generalized EEG pattern group, (d) CPT foci group (CPT group), and (e) no epileptic EEG focus group. The Fp-O group showed the latest age at onset of epilepsy. The generalized EEG pattern group had the highest frequency of seizures as well as recurrences of status epilepticus (SE), as well as the longest active seizure period among the five groups. CONCLUSIONS: These results indicated that the EEG foci in most of patients with PS are frequently shifting location, multiplying, and propagating diffusely with age, rather than persistently localizing in the occipital region. In addition, the EEG patterns showed a certain trend and roughly corresponded to certain clinical characteristics. However, the prognosis of the seizures appeared to be favorable regardless of the EEG pattern.     

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.     

Clinical implications of preceding positive spikes in patients with benign partial epilepsy and febrile seizures

Purpose: To clarify the clinical implications of the preceding positive spikes (PPSs) observed primarily in rolandic spikes, we analyzed PPSs in the rolandic and occipital spikes observed in the electroencephalograms (EEGs) of patients with two types of benign partial epilepsies (benign childhood epilepsy with centro-temporal spikes [BECT] and Panayiotopoulos syndrome [PS]) and febrile seizures (FS). Subjects and methods: We identified patients from our outpatient EEG database that were seen between 2006 and 2008 that had BECT, PS, and FS with rolandic or occipital spikes. We generated an averaged spike for each patient from the rolandic and occipital spikes that were detected using an automatic spike detection and clustering system. We compared the presence rate of the averaged spikes with the PPS among the three groups (BECT vs. PS vs. FS) using sequential mapping. Results: We identified 25 BECT, 18 PS, and 15 FS patients with rolandic spikes. Fifteen BECT and nine PS patients exhibited a PPS in their averaged rolandic spikes, whereas only four FS patients did. Three of these four FS patients later developed afebrile seizures, and one of them was diagnosed as having PS. We analyzed eight PS and six FS patients with occipital spikes. Five PS patients exhibited a PPS in their averaged occipital spikes, whereas only one FS patient did. This FS patient later developed prolonged autonomic febrile seizures. Conclusion: PPSs are observed not only in rolandic spikes associated with BECT that is related strictly to sylvian seizures, but also in rolandic and occipital spikes associated with PS. Although PPSs are rare in such spikes observed in FS, patients with FS and PPSs may have an increased risk of developing afebrile seizures or prolonged autonomic febrile seizures. Further studies are warranted to determine the diagnostic utility of PPSs as a marker of the future development of epilepsy when they are observed in FS patients.     

Epileptic encephalopathy with continuous spikes and waves during sleep in children with shunted hydrocephalus: a study of nine cases

Purpose: We present a series of nine patients with early‐onset hydrocephalus who had seizures and continuous spikes and waves during slow sleep (CSWS) associated with neurocognitive and motor deterioration. Methods: Six boys and three girls aged 9–16 years (mean 11.3 years) were studied. [Correction added after online publication 12‐Apr‐2008: Number of girls and boys has been updated.] All patients underwent clinical examinations, electroencephalographic evaluations, neuroradiological imaging and neuropsychological assessment at first examination. Antiepileptic drugs (AEDs) were given in all cases and changed according to clinical and EEG evolution. Results: Onset of epilepsy occurred from age 8 to 60 months (mean 19.6 months and median 14 months) with focal seizures with or without secondary generalized tonic–clonic seizures. Between ages 6 and 13 years (mean 10.4 years and median 8 years), hyperkinesia, aggressiveness, and poor socialization appeared in all nine cases. Reduced attention span, deterioration of language, and temporospatial disorientation were found in three of them. Negative myoclonus was found in two patients. The EEG showed CSWS. Response to change in treatment was good in all patients. None of the patients had relapses, seven of them have remained seizure free, and two continued having sporadic focal motor seizures during 2–5 years (mean 3 years) of follow‐up. Conclusion: In children with early‐onset hydrocephalus, particularly with behavioral and language disturbances and/or motor deterioration, CSWS should be considered. Periodic EEG recordings during sleep should be done in these children. The early identification of this particular electroclinical picture is crucial to start adequate treatment to avoid progressive cognitive deterioration.     

Panayiotopoulos-type benign childhood occipital epilepsy: a prospective study

OBJECTIVE: To characterize the clinical and EEG features of the syndrome of benign childhood partial seizures with ictal vomiting and EEG occipital spikes (Panayiotopoulos syndrome [PS]). METHODS: Prospective study of children with normal general and neurologic examinations who had seizures with ictal vomiting and EEG with occipital spikes. RESULTS: From February 1990 to 1997, the authors found 66 patients with PS and 145 children with benign childhood epilepsy with centrotemporal spikes. Peak age at onset of PS was 5 years. Ictal deviation of the eyes and progression to generalized seizures were common. One-third had partial status epilepticus. During sleep, all had seizures. While awake, one-third also had seizures. Five children with PS had concurrent symptoms of rolandic epilepsy and another five developed rolandic seizures after remission of PS. Prognosis was excellent: one-third had a single seizure, one-half had two to five seizures, and only 4.5% had frequent seizures. CONCLUSIONS: Panayiotopoulos-type benign childhood occipital epilepsy is less common than benign childhood epilepsy with centrotemporal spikes but is well defined and recognizable by clinical and EEG features.     

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。     

The tower of Babel: Survey on concepts and terminology in electrical status epilepticus in sleep and continuous spikes and waves during sleep in North America

Purpose: The terms “electrical status epilepticus during sleep (ESES)” and “continuous spikes and waves during sleep (CSWS)” have been used interchangeably when referring to related but different concepts. In addition, the quantification of epileptiform activity has not been standardized, and different approaches to quantification have been used. The aim of this study was to evaluate the extent to which pediatric neurologists and epileptologists use a homogeneous terminology and conceptualization in CSWS and ESES and to characterize the current understanding of these conditions. Methods: A survey addressing the use of terminology in “ESES” and “CSWS” and the understanding of related concepts was distributed online to all members of the Child Neurology Society and the American Epilepsy Society mailing lists. Surveys were self‐administered and collected using an online survey website ( http://www.surveymonkey.com ). Key Findings: Two hundred nineteen surveys were completed, 137 from the Child Neurology Society mailing list and 82 from the American Epilepsy Society mailing list. ESES and CSWS were considered synonymous by 117 respondents, not synonymous by 61, 21 respondents did not know, and 20 did not respond. Most respondents (63.1%) considered CSWS as a devastating epileptic encephalopathy with severe sequelae even if treated correctly, but 25.1% of respondents indicated that it does not leave sequelae if epilepsy was treated early and another 11.8% noted that cognitive difficulties resolved with age. Cognitive and/or language regression were considered mandatory for the diagnosis of CSWS by only 27% of the respondents. The diagnosis of CSWS was based on electroencephalography (EEG) assessment alone by 31% of respondents. Respondents used different methods for calculation of the epileptiform activity, different EEG samples for calculation, and considered differently the lateralized epileptiform activity. The cut‐off values for percentage of the sleep record occupied by spike‐waves were variable depending on the respondent. There was no agreement on whether these cutoff values were mandatory for the diagnosis of ESES and CSWS. Significance: Our data show that the professionals caring for children with ESES and CSWS in North America use the terms, concepts, and defining features heterogeneously. The lack of a common language may complicate communication among clinicians and jeopardize research in this field. We anticipate that our data will fuel the development of much needed common terminology and conceptualization of ESES and CSWS.     

Role of interictal epileptiform abnormalities in cognitive impairment

The epileptic encephalopathies are conditions in which neurological deterioration is attributable entirely or partly to epileptic activity and is due to very frequent or severe seizures or severely abnormal electroencephalograms (EEGs), or both. Evidence for the concept that seizures or the abnormal EEGs are responsible for the cognitive deterioration is the observation that patients can improve dramatically when therapy eliminates or reduces seizure frequency and improves or normalizes the EEG. For example, children with the syndrome of continuous spike-wave of sleep (CSWS) have electrical status epilepticus during sleep (ESES) and cognitive regression. Although seizures often occur in the disorder, there are indications that the EEG abnormalities are responsible for the cognitive regression. Interictal spikes, which correspond to a large intracellular depolarization with evoked action potentials, in many ways mimic a "miniseizure." Interictal spikes can result in transitory cognitive impairment with the type of deficit dependent on where in the cortex the spike arises. We suggest that interictal spikes, particularly if frequent and widespread, can impair cognitive abilities, through interference with waking learning and memory, and memory consolidation during sleep.     

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.     

Epilepsy and sleep: with special reference to nonconvulsive status epilepticus with continuous diffuse spike-waves during slow-wave sleep

There are numerous important problems concerning relationship between epilepsy and sleep. To clarify the clinical significance and pathophysiology of the nonconvulsive status epilepticus with continuous diffuse spike-waves during slow-wave sleep (CSWS) in EEG, this study was carried out on seven cases each of epilepsies with electrical status epilepticus during slow sleep (ESES) and with peculiar type of nonconvulsive status epilepticus in childhood (PNSE) and four cases of atypical benign partial epilepsy (ABPE). Mental deterioration was most frequently observed in ESES, less in PNSE but none in ABPE. In both ESES and PNSE, mentally deteriorated cases showed suppression of CSWS at significantly later ages than those without deterioration. And spike-wave indices during slow-wave sleep, which were the highest in ESES and lower in PNSE and ABPE, also had a strong relation to mental deterioration. In these three disorders, both clinical seizures and CSWS were suppressed at or before 16 years of age, although they were intractable before adolescence. This finding indicated age dependent evolutions of the three disorders. Coherence and phase analysis of CSWS was undertaken to differentiate primary and secondary bilateral synchrony in seven cases of these three disorders, which have both features of generalized and partial epilepsies. This analysis disclosed secondary bilateral synchrony as the nature of CSWS in six cases. And this analysis method was considered to provide a clue to their pathophysiology. Thus, in these disorders, importance of early diagnosis by EEG including deep sleep and early treatment was recognized.     

High‐frequency oscillations in idiopathic partial epilepsy of childhood

Purpose: We explored high‐frequency oscillations (HFOs) in scalp sleep electroencephalography (EEG) studies of patients with idiopathic partial epilepsy (IPE) of childhood in order to obtain a better understanding of the pathologic mechanisms underlying IPE. Methods: The subjects were 45 patients, including 32 with benign childhood epilepsy with centrotemporal spikes (BCECTS) and 13 with Panayiotopoulos syndrome (PS). A total of 136 EEG records were investigated through temporal expansion and filtering of traces and time‐frequency spectral analysis. Key Findings: HFOs with frequency of 93.8–152.3 Hz (mean 126.2 ± 13.6 Hz) in the band of ripples were detected in association with spikes in 97 records (71.3%). Time from last seizure to the EEG recording was significantly shorter in those with spike‐related HFOs than in the EEG recordings with spikes without HFOs (p = 0.006). Although time from last seizure reflects age, age at the time of recording was not significantly different between EEG studies with and without HFOs. Peak‐power values of the high‐frequency spots in time‐frequency spectra were significantly negatively correlated with time from last seizure (R² = 0.122, p < 0.001) but not with age at the time of recording. Peak frequencies of the high‐frequency spectral spots were not significantly correlated with age at the time of recording or with time from last seizure. Significance: The close relationship between the generation of spike‐related HFOs and the period of active seizure occurrence indicated that HFOs may tell us more about epileptogenicity in IPE than the spikes themselves. Because there is a spectrum of pediatric epileptic disorders extending from the benign end of BCECTS to the encephalopathic end of epilepsy with continuous spike‐waves during slow‐wave sleep (CSWS), and HFOs that have already been detected in association with CSWS were more prominent than HFOs in IPE, intense spike‐related HFOs may indicate poor prognosis.     

Epilepsy with Electrical Status Epilepticus During Slow Sleep and Secondary Bilateral Synchrony

Summary: In 3 children with "epilepsy with electrical status epilepticus during slow sleep" (ESES), we estimated interhemispheric small time differences (TDs) during spike-wave activity in EEG by coherence and phase analysis by the two-dimensional autoregressive model to differentiate their continuous diffuse spike-waves during slow-wave sleep (CSWS) between primary bilateral synchrony and secondary bilateral synchrony (SBS). Maximal TDs at onset of apparently bilateral synchronous spike-wave bursts (BSSWs) during slow-wave sleep were 12·0–26·5 ms (mean 20·3 ms) with consistent leading hemispheres in eight bursts of the 3 patients, indicating SBS as pathophysiology of their CSWS. This suggestion was supported by their clinico-EEG findings, including the effect of a single oral dose of clobazam (CLB) on EEG. Three ictal BSSWs of atypical absence seizures in 2 patients were also analyzed to obtain maximal TDs of 17·9–41·7 ms (mean 26·3 ms) at onset, with the same leading sides as in sleep, also indicating SBS. Examination of intraburst TD variations showed no consistent disappearance of TDs during the latter part of the bursts, in either sleep or the ictal EEGs of atypical absences, and a role of the corpus callosum was suggested in the generation of SBS in ESES.