A de novo loss-of-function GRIN2A mutation associated with childhood focal epilepsy and acquired epileptic aphasia

OBJECTIVE

N-methyl-D-aspartate receptors (NMDAR) subunit GRIN2A/GluN2A mutations have been identified in patients with various neurological diseases, such as epilepsy and intellectual disability / developmental delay (ID/DD). In this study, we investigated the phenotype and underlying molecular mechanism of a GRIN2A missense mutation identified by next generation sequencing on idiopathic focal epilepsy using in vitro electrophysiology.

METHODS

Genomic DNA of patients with epilepsy and ID/DD were sequenced by targeted next-generation sequencing within 300 genes related to epilepsy and ID/DD. The effects of one missense GRIN2A mutation on NMDAR function were evaluated by two-electrode voltage clamp current recordings and whole cell voltage clamp current recordings.

RESULTS

We identified one de novo missense GRIN2A mutation (Asp731Asn, GluN2A(D731N)) in a child with unexplained epilepsy and DD. The D731N mutation is located in a portion of the agonist-binding domain (ABD) in the GluN2A subunit, which is the binding pocket for agonist glutamate. This residue in the ABD is conserved among vertebrate species and all other NMDAR subunits, suggesting an important role in receptor function. The proband shows developmental delay as well as EEG-confirmed seizure activity. Functional analyses reveal that the GluN2A(D731N) mutation decreases glutamate potency by over 3,000-fold, reduces amplitude of current response, shortens synaptic-like response time course, and decreases channel open probability, while enhancing sensitivity to negative allosteric modulators, including extracellular proton and zinc inhibition. The combined effects reduce NMDAR function.

SIGNIFICANCE

We identified a de novo missense mutation in the GRIN2A gene in a patient with childhood focal epilepsy and acquired epileptic aphasia. The mutant decreases NMDAR activation suggesting NMDAR hypofunction may contribute to the epilepsy pathogenesis.

[Efficacy of methylprednisolone therapy for electrical status epilepticus during sleep in children]

OBJECTIVE

To evaluate the therapeutic effect of methylprednisolone for electrical status epilepticus during sleep (ESES) in children.

METHOD

The clinical and EEG data of 82 epilepsy patients with ESES, which included benign childhood epilepsy with centro temporal spikes (BECT) variants, epilepsy with continuous spikes and waves during slow sleep (CSWS) , Landau-Kleffner syndrome (LKS) collected from department of pediatrics, Peking University First Hospital were analyzed from July 2007 to September 2012. During ESES period, all patients received methylprednisolone treatment for three courses, which included methylprednisolone intravenous infusion for three days, followed by oral prednisone for four days every time. After three courses, prednisone [1-2 mg/(kg × d)] were taken by all patients for 6 months. The ESES phenomenon and seizures were observed before and after treatment. The efficacy of corticosteroid on ESES suppression, seizure control of three epilepsy syndrome were analyzed.

RESULT

Thirty-nine cases were male and 43 cases were female. The epilepsy syndromes included 49 patients diagnosed as benign childhood epilepsy with centrotemporal spike (BECT) variants, 27 patients diagnosed as epilepsy with continuous spikes and waves during slow sleep (CSWS), and 6 patients diagnosed as LKS. Age of onset ranged from 1 year and 4 months to 11 years. The age of ESES newly monitored was from 2 years to 10 years and 8 months. The total effective rate of corticosteroid was 83% (68/82) for ESES, BECT variants was 82% (40/49), CSWS was 81% (22/27), LKS was 100% (6/6). There was no statistically significant difference in effective rates between the front two (χ² = 0.09, P > 0.05). The seizures were improved in the first month after methylprednisolone treatment in 3 epilepsy syndromes. The recurrence rate of BECT variants was 47% (23/49) , CSWS was 59% (16/27) , LKS was 50% (3/6) after 1 year follow up. There was no association between disease parameters, including age at seizure onset, duration of ESES and the treatment effect of ESES examined by Kruskal-Wallis method (χ² = 3.585, 0.932, P > 0.05).

CONCLUSION

Methylprednisolone was effective for improving ESES and seizures in 3 epilepsy syndromes combined with ESES. There was no significant correlation between age at seizure onset, duration of ESES and treatment effect of ESES.

Sparse MEG source imaging in Landau-Kleffner syndrome

Epilepsy patients with Landau-Kleffner syndrome (LKS) usually have a normal brain structure, which makes it a challenge to identify the epileptogenic zone only based on magnetic resonance imaging (MRI) data. A sparse source imaging technique called variation based sparse cortical current density (VB-SCCD) imaging was adopted here to reconstruct cortical sources of magnetoencephalography (MEG) interictal spikes from an LKS patient. Realistic boundary element (BE) head and cortex models were built by segmenting structural MRI. 148-channel MEG was recorded for 10 minutes between seizures. Total 29 epileptiform spikes were selected for analysis. The primary cortical sources were observed locating at the left intra- and perisylvian cortex. Multiple extrasylvian sources were identified as the secondary sources. The spatio-temporal patterns of cortical sources provide more insights about the neuronal synchrony and propagation of epileptic discharges. Our observations were consistent with presurgical diagnosis for this patient and observation of aphasia in LKS. The present results suggest that the promising of VB-SCCD technique in assisting with presurgical planning and studying the neural network for LKS in determining the lateralization of epileptic origins. It can further be applied to non-invasively localize and/or lateralize eloquent cortex for language for epilepsy patients in general in the future.

The concept of epileptic networks. Part 2

In this paper we investigate evidences supporting the network concept of epilepsies from different approaches. Firstly the functions of cortical networks in which most of the epileptic networks are embedded, are treated. Then the tentative characteristics of an epileptic network are enumerated and the conversion mechanisms from physiological to epileptic networks are analyzed. Later the role of neuronal oscillations in epileptic networks and aspects of epilepsies provoked by sensory and cognitive tasks is studied. Lastly new fMRI data in mapping BOLD networks underlying spike and seizure discharges are used as arguments in favour of the epileptic network hypothesis. In a second part the well-known epilepsies related, or probably related to physiological networks are shown. Finally consequences of the network approach for creating a new unified epilepsy classification are discussed.

[Neurocognitive dysfunction in electrical status epilepticus during slow-wave sleep syndrome: Can the natural course of the syndrome be modified with early pharmacological treatment?]

INTRODUCTION

Epileptic syndromes with continuous spike wave in slow-wave sleep (CSWS), including electrical status epilepticus in sleep (ESES) and Landau-Kleffner syndrome, are true epileptic encephalopathies where sustained epileptic activity is related to cognitive and behavioural decline.

AIMS

To review the natural course of ESES, to define the general principles of treatment of epileptic syndromes with CSWS, to delineate the different options that are currently available for treating these epileptic encephalopathies, and to analyze the prognostic factors linked to pharmacological treatment of ESES.

DEVELOPMENT

Epileptic syndromes with CSWS are initially treated with a pharmacologic intervention with polytherapy of antiepileptic drugs in most cases. However, due to the poor response that CSWS often have to antiepileptic drugs, non-pharmacologic treatment options are an important part of a comprehensive treatment plan for this group of children. This article discusses the use of corticosteroids, intravenous immunoglobulins, ketogenic diet, vagus nerve stimulation, and epilepsy surgery in the treatment of patients with epileptic syndromes with CSWS.

CONCLUSIONS

Treatment of ESES extends beyond just control of the seizures; amelioration of the continuous epileptiform discharge must occur to improve neuropsychological outcome. There is a significant correlation between the length of the ESES period and the extent of residual intellectual deficit at follow-up. According to this knowledge, there is a well defined therapeutic interval where our different strategies of treatment may be useful, and the upper limits of this time frame to a critical period of 12-18 months.

HEMISPHERIC INTEGRATIVE THERAPY IN LANDAU-KLEFFNER SYNDROME: APPLICATIONS FOR REHABILITATION SCIENCES

A case study is presented of a 14-year-old right-handed Caucasian female diagnosed with the Landau-Kleffner Syndrome (LKS) at the age 3 1/2 years. Her LKS symptoms presented with abrupt disruption in language after normal development, electroencephalogram (EEG) brain-wave abnormality, seizure activity, inability to read, and impairment in her motor skills. After 11 years of pharmacological and special education interventions with no significant improvement in any measurable area of function, a multimodal approach using techniques purportedly aimed at facilitating inter-hemispheric communication was provided. At completion of the program, EEG was controlled, reading, language, and auditory processing improved and objective behavioral-social measures improved significantly.

Possible involvement of the tip of temporal lobe in Landau-Kleffner syndrome

Landau-Kleffner syndrome (LKS) is a childhood disorder of unknown etiology characterized by an acquired aphasia and epilepsy. We have performed comprehensive neurofunctional studies on an 8-year-old girl with typical LKS, with the aim of identifying lesions that may be responsible for her condition. 18F-fluoro-D-glucose (FDG) positron emission computed tomography (PET), 11C-Flumazenil (FMZ) PET, 99mTc-hexamethylpropyleneamine oxime single photon emission computed tomography (SPECT) and magnetoencephalography were performed before and after changes to the patient's medication led to a clinical improvement. Interictal SPECT showed hypoperfusion in the left frontal, left temporal, and left occipital lobes. 18F-FDG PET demonstrated a decrease in glucose metabolism medially in both temporal lobes and superiorly in the left temporal lobe. 11C-FMZ PET revealed a deficit in benzodiazepine receptor binding at the tip of the left temporal lobe. Magnetoencephalography demonstrated equivalent current dipoles located superiorly in the left temporal lobe. Our results suggest that the tip of the left temporal lobe plays an important role in the pathogenesis of LKS in our patient.

[Landau-Kleffner syndrome: an analysis of 10 cases in Venezuela]

INTRODUCTION

Landau-Kleffner syndrome is characterised by acquired aphasia and encephalographic alterations that may or may not be accompanied by epileptic seizures. AIM. To analyse the clinical and encephalographic features and response to treatment of 10 patients with Landau-Kleffner syndrome.

PATIENTS AND METHODS

We reviewed the patient records, encephalograms and treatment administered to patients catalogued as having Landau-Kleffner syndrome.

RESULTS

The mean age of the patients was 44 months. Of these cases, 60% presented epilepsy when the diagnosis was established and 70% were found to have epileptic status during slow-wave sleep in the encephalographic study. Results showed that 40% corresponded to variants of Landau-Kleffner syndrome. No cause of the disease could be established in any of the patients. In the neuroimaging study, only one patient displayed abnormalities in the magnetic resonance imaging of the brain. All the patients received adrenocorticotropic hormone (ACTH)-based treatment, at a dose of 1 IU/kg/day for one month, administered together with antiepileptic drugs such as valproic acid and clobazam. Convulsive seizures and epileptic status during slow-wave sleep disappeared in all the patients. In the patients without epileptic status, epileptic activity became less frequent, although it did not completely disappear. Aphasia improved considerably, which meant that all the patients were able to enroll in normal schools.

CONCLUSIONS

We believe that early diagnosis, together with suitable and timely management of aphasic patients with encephalographic alterations that allow ACTH to be used at low doses, make it possible to offer an early education so as to provide maximum recovery from the disease.

Using the language characteristics of clinical populations to understand normal language development

The overall purpose of this article is to describe the speech and language abilities of children who have selected clinical conditions, not only to characterize the outcomes of those conditions, but also to understand fundamental requirements for language learning in typically developing children. This developmental cognitive neuroscience analysis conceptualizes the clinical conditions as naturalistic experimental manipulations, selectively altering factors in the language-learning situation that could not otherwise be ethically manipulated in a research study.

The spectrum from BCECTS to LKS: The Rolandic EEG trait-impact on cognition

The laboratory hallmark of BCECTS is the rolandic discharge (RD) in the EEG of patients, occurring in a characteristic topographical, vigilance-related, event-related, and age-related pattern, disappearing during puberty. RDs are present in 2% of healthy children. About 8% of children with RDs have epilepsy. An increased prevalence rate of RDs is found in children with cognitive and behavioral disorders, with headaches and some genetic syndromes. In some patients, the cognitive disorders are transient but in others they are progressive, resulting in stable mental retardation after puberty. A recent study of 36 BCECTS patients addressed the following questions. (1) the possible relationship between the severity of RDs and the neuropsychological deficits; (2) the profile of neuropsychological deficits; (3) changes of cognition related to EEG changes; and (4) effects of therapy. No correlation was found between global IQ and the severity of the RDs. All the children had at least one specific learning disorder (sometimes long-lasting). When the children were treated, a correlation between cognitive and EEG improvement could not be demonstrated. Recently, 21 patients without epilepsy but with attention deficit and hyperactivity and/or learning disorders were studied: an open treatment trial with sulthiame resulted in improved sustained and selective attention. The neurobiology of RDs and their relationship to cognitive dysfunction and epilepsy requires further study.

Neuropsychological findings in Rolandic epilepsy and Landau-Kleffner syndrome

In an attempt to correlate neuropsychological deficits and various neurophysiological aspects of focal epileptic activity in benign childhood epilepsy, we have reviewed the findings of a longitudinal group study of benign childhood epilepsy with centrotemporal spikes (BCECTS) and several case studies of continuous spike-waves during slow sleep syndrome (CSWS). We first distinguish the temporary neuropsychological impairments often observed in the natural history of BCECTS from the more long-lasting and more specific neuropsychological deficits associated with CSWS, of which the Landau-Kleffner syndrome (LKS) is the most studied clinical form. A series of metabolic findings from (18)FDG-PET studies in BCECTS and CSWS children have shown that specific cognitive impairment is related to increased glucose uptake in cortical areas restricted to the associative cortex coincident with the focus of spike-wave discharges. From recent functional neuroimaging data of three patients recovered from LKS, we address the issue of the pathophysiology of cognitive impairment persisting after complete recovery of epilepsy. Finally, we discuss the reliability of the study of mismatch negativity to address the issue of the early effect of interictal discharges in typical and atypical BCECTS on the auditory cortex and the development of speech processing essential to verbal learning.

An in computo investigation of the Landau-Kleffner syndrome

We describe a computational model of the thalamus and the cortex able to reproduce some essential epileptiform features commonly observed in the Landau-Kleffner syndrome. Investigation with this realistic model leads us to the formulation of a cellular mechanism that could be responsible for the epileptic discharges occuring with this severe syndrome. Understanding this mechanism is of prime importance for developing new therapeutical strategies.

Episodic receptive aphasia in a child with Landau-Kleffner Syndrome: PET correlates

We report a four-year-old boy with Landau-Kleffner Syndrome (LKS) characterized by episodic receptive aphasia lasting for few weeks followed by gradual recovery of baseline language functions. Neuropsychological evaluation during an episode showed severe impairment in verbal skills and comprehension, but relative preservation of non-verbal skills. Although he could carry on a conversation during remission, neuropsychological evaluation demonstrated findings reflective of receptive language deficits. Prolonged EEG disclosed frequent sharp-wave activity in the left and right temporal regions but no electrographic seizures. Glucose metabolism PET scan during the fourth episode of aphasia revealed intense hypermetabolism in the left temporal neocortex. Awake EEG during the PET tracer uptake period showed 6.0 spikes/min in the left temporal region and 4.0 spikes/min in the right. A repeat PET scan during remission showed hypometabolism in the left temporal cortex. Awake EEG during the FDG uptake period showed 16.0 spikes/min in the right temporal region and 0.3 spikes/min in the left. During his fifth aphasic episode, EEG (without PET) showed 0.16 spikes/min in the right temporal region and none in the left. Intermittent short episodes of predominantly receptive aphasia with near-total recovery between episodes can be one of the clinical presentations of LKS. This case illustrates the dynamic changes of glucose metabolism in the temporal lobe during episodes of aphasia and remission in a case with LKS. The clinical course of our patient with transient EEG and PET findings suggest that glucose metabolism in LKS cannot be attributed solely to interictal epileptiform activities on scalp EEG.

Landau–Kleffner syndrome is not an eponymic badge of ignorance

In a 1992 editorial article, Landau expressed the hope of collective agreement in the medical community about Landau-Kleffner syndrome (LKS) in terms of diagnosis criteria, etiology, pathophysiology and rational therapy. Since then, neurophysiological and neuroimaging studies have led to the view that LKS is an acquired aphasia, secondary to an epileptic disturbance affecting a cortical area involved in verbal processing. This fits with the hypothesis of a "functional ablation" caused by epileptic activity. Under these criteria, epileptic aphasia becomes a subgroup of the continuous spike-waves syndrome in which epileptic discharges originate from the temporal cortex. Genetic predisposition for KLS could be related to hyperexcitability and synchronization of interneurons within the perisylvian cortices, which generate the spike-waves. Activation of these waves during NREM sleep, following thalamo-cortical uncoupling, might then alter the blood brain barrier and provoke an autoimmune reaction. Interneuron hyperactivity might in turn have an antiepileptic protective effect, associated with the inhibition of a specific function, and spike-waves activity over the long term might eventuate in focal atrophy. This morphological defect might explain the poor verbal outcome in some cases of LKS. From this study we recommend a multicenter control study of good design and methodology be carried out to compare the efficacies of early versus delayed (3 months) corticosteroid treatment in patients with typical LKS that is being treated by clobazam (or diazepam) monotherapy.

Children with ESES: variability in the syndrome

OBJECTIVE

We undertook a retrospective study of children who present with significant activation of paroxysmal discharges during sleep to examine the clinical spectrum of disorders that present with such an EEG abnormality.

BACKGROUND

Electrical status epilepticus in sleep (ESES) is an electrographic pattern characterized by nearly continuous spike-wave discharges in slow wave sleep, usually with a frequency of 1.5-3 Hz and usually diffuse and bilateral in distribution. A variety of neurocognitive and behavioral problems have been associated with this EEG pattern.

METHODS

We conducted a retrospective review of 1497 EEG records of patients admitted to University of California, Los Angeles (UCLA) for overnight video-EEG monitoring during a 5 year interval. Demographic, clinical and electroencephalographic variables were evaluated.

RESULTS

EEG records for 102 patients meeting criteria were identified. Clinical information was available for 90 of those patients. Eighteen of these patients could be diagnosed with Landau-Kleffner syndrome (LKS). Key findings include: (1) neuroimaging abnormalities were uncommon in our LKS patients; (2) among children who do not fit the specific diagnostic criteria for LKS, a spike-wave index (SWI) >50% was more likely to be associated with global developmental disturbances than SWI < or =50% (p<0.05); (3) Children with generalized discharges were more likely to experience severe or global developmental disturbance than those with focal abnormalities, without reaching statistical significance (p=0.07).

CONCLUSIONS

Severity of ESES can vary over time between and within patients and clinical status does not always directly correlate with SWI. However, the prognosis of LKS is substantially better than CSWS and these two disorders could be classified in a dichotomous manner rather than be seen as two points along a continuum.

The pathophysiological mechanisms of cognitive and behavioral disturbances in children with Landau–Kleffner syndrome or epilepsy with continuous spike-and-waves during slow-wave sleep

Epilepsy with continuous spike- and -waves during slow-wave sleep and Landau-Kleffner syndrome are two rare childhood epilepsy syndromes. The underlying pathophysiology remains unknown. The current opinions about epidemiologic risk factors, genetic predisposition, EEG and MEG findings, influence of anti-epileptic drugs, neuroradiology, positron emission tomopgraphy, evoked potentials, auto-immunity and subpial transection are summarized.

[Clinical characteristics and long-term prognosis of Landau-Kleffner syndrome]

OBJECTIVE

To investigate the clinical and electroencephalographic (EEG) characteristics, therapeutic response and long-term prognosis of Landau Kleffner syndrome (LKS).

METHODS

The clinical and EEG data of 10 children with LKS were analyzed, and therapeutic response and long-term outcome were followed up.

RESULTS

The age of onset was from 2 to 10.5 years of age. All patients had acquired aphasia, characterized by verbal auditory agnosia. All patients had epileptic seizures. Partial motor seizures during sleep occurred in 8 patients, and other seizure type including atypical absence seizure and generalized tonic-clonic seizure were also observed. Psychological and behavioral abnormalities occurred in 9 patients. There were no abnormalities of hearing and neuro-imaging tests in all patients, and family histories were negative. All the patients had EEG abnormalities. Focal spike and waves of temporal lobe were recorded in 9 patients. Electrical status epilepticus during sleep (ESES) was observed on Video-EEG (VEEG) monitoring in 4 patients. Anti-epileptic drugs (AEDs) showed favorable effects on epileptic seizures, but no effects on aphasia. All patients responded to corticosteroid, and got language improved. Eight patients were followed up for long-term outcome. All patients were seizure free, while the level of language development was abnormal in 5 patients. The VEEG follow-up was conducted in 6 patients. Continuous epileptic discharges in slow sleep recurred in 2 patients after the discontinuation of steroid therapy.

CONCLUSIONS

LKS is one of the childhood epileptic encephalopathy, and acquired aphasia and epileptic seizures are two main clinical characteristics. Aphasia is characterized by verbal auditory agnosia. Psychological and behavioral abnormalities are very common in children with LKS. Focal epileptic discharges were often located in temporal area, and usually generalized, and could be continuous during sleep. AEDs could control seizure but had no effects on aphasia. Early use of full dose corticosteroids could improve the language significantly. Long-term follow up showed that language impairments often remained, but the outcome in terms of EEG and epileptic seizure was good.

Corticosteroids for the treatment of Landau-kleffner syndrome and continuous spike-wave discharge during sleep

Landau-Kleffner syndrome and its variants such as continuous Spike-Wave Discharge during Sleep (CSWS) are progressive epileptic encephalopathies of childhood. The treatment of this unusual group of patients is controversial. We describe our experience in treating patients with Landau-Kleffner syndrome and CSWS with corticosteroids. The patients received Prednisone 1 mg/kg/day for 6 months, 1 year, then yearly. Follow-up was for 1-10 years (mean 4 years). Ten patients, 3 females, 7 males were studied. Age of onset ranged from 2 to 11 years (mean 7.5 years). Eight patients manifested Landau-Kleffner syndrome, and two had CSWS. Most patients had seizures (8/10); however, two patients did not have clinical seizures. MRI was normal in all patients. SPECT scan was abnormal in four patients, normal in three, and not available in three. All but one patient manifested significant improvement in language, cognition, and behaviour, which continued after the corticosteroid trial. Side effects were few (4/10) and transient and consisted of weight gain (2), behavioral change (1), and hypertension (1). Corticosteroids are a safe and effective treatment for patients with Landau-Kleffner syndrome and CSWS. Most patients had improvement in language, cognition, and behaviour after treatment. Side effects are few and reversible, and benefits appear long lasting. Corticosteroids should be considered as a treatment option in children with Landau-Kleffner syndrome and CSWS.

A Clinical and EEG Study on Idiopathic Partial Epilepsies with Evolution into ESES Spectrum Disorders

PURPOSE

Questioning the presence of any possible prognostic predictors, this study includes a long-term follow-up of clinical and EEG characteristics of 16 patients with idiopathic partial epilepsy (IPE) who subsequently developed epilepsy with electrical status epilepticus during slow sleep (ESES) spectrum disorders.

METHODS

Epilepsy, cognitive and behavioral parameters, and waking and non-rapid eye movement (NREM) EEG data were evaluated and scored for initial stage (i.e., IPE stage), preESES, ESES, and ESES remission periods, individually, on a chronologic basis. Data from 25 healthy subjects who had had IPE at the appropriate ages served for comparison with the patients' data during the IPE stage.

RESULTS

Results revealed a higher incidence in seizure frequency and variability in the ESES group and a resistance to a single antiepileptic drug (AED), as compared with controls, during the IPE stage. Mean age at onset of epilepsy was younger in the ESES group versus controls (5.5 and 7.3 years, respectively). At least one of the premonitory clinical features for development of ESES [an increase in the seizure frequency and/or addition of new types of seizures (93%), appearance of cognitive and/or behavioural changes (81.2%), or a progression in EEG abnormalities (66%)] was present in all patients. Epilepsy remitted in patients within the ESES spectrum at a similar age as in controls in 81.2%, as ESES findings in the EEG disappeared by age 13 years in 94%. Seizure prognosis proved to be the most favorable among the questioned parameters.

CONCLUSIONS

An increase in seizure frequency or development of new seizure types, a deviance in behavior or decrease in cognitive performance, or a spreading tendency of the previously focal abnormalities in control EEGs may be premonitory features of a developing ESES and necessitate close follow-ups with sleep EEGs in children with IPEs.

The perisylvian epileptic network. A unifying concept

In this work the authors provide evidences for a unifying concept of the syndromes of benign focal childhood epilepsies, Landau-Kleffner syndrome, and electrical status epilepticus in sleep treating them as a spectrum of disorders with a common transient, age dependent, non lesional, genetically based epileptogenic abnormality, the nature of which is still not known. The electro-clinical features of these syndromes are congruent with the different degree involvement of the perisylvian cognitive network and with the involvement of the thalamo-cortical associative system of variable degree. These epilepsies are characterized by the abundance of regional epileptiform discharges in sharp contrast with the rare and in several cases lacking seizures. The nature and severity of interictal cognitive symptoms are closely related to localization within the network and amount of epileptic interictal discharges. Spike-wave discharges are attributed to an alternation of overexcitation (spikes) and overinhibition (waves). The recurrent overinhibition represented by the wave of the discharges may interfere with the continuous depolarization of the cells of a large population of neurons, which is a requirement of the overt seizures. The overinhibition also interfere with cognitive processes which are correlated with the continuous presence of the fast (gamma) activity, binding the required cortical areas. Hence the recurrent inhibition works against the existence of the binding fast frequency activity. This is the assumed reason for the co-existence of the relative lack of overt seizures and in the same time for the frequently observed epileptogenic cognitive deficit symptoms ("cognitive epilepsies"). The time course of these syndromes overlaps with important developmental milestones. The frequent epileptic discharges alters the evolution of the perisylvian network developing late after early childhood and is very vulnerable for any interference in this imprinting time for speech and other cognitive functions. This spectrum of disorders represents a type of age linked, mild to severe 'epileptic encephalopathy' limited to the perisylvian network, where the cognitive impairment is caused by epileptic discharges interfering with cognitive development.

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.

Outcome at adulthood of the continuous spike-waves during slow sleep and Landau-Kleffner syndromes

PURPOSE

The aim of this study was to determine the clinical, social, and/or professional and cognitive outcomes in adulthood of the continuous spike-waves during slow sleep (CSWS) and Landau-Kleffner syndromes, which are two rare epileptic syndromes occurring in children.

METHODS

We enrolled seven young adults, five who had a CSWS syndrome, and two, a Landau-Kleffner syndrome in childhood. We evaluated their intellectual level as well as their oral and written language and executive functions.

RESULTS

This study confirmed that the epilepsy associated with these syndromes has a good prognosis. Only one patient still had active epilepsy. However, the neuropsychological disorders particular to each syndrome persisted. Only two patients had followed a normal pathway in school. Three of the five patients with a CSWS syndrome during childhood remained globally and nonselectively mentally deficient. We found no evidence of the persistence of a dysexecutive syndrome in this study group. The intellectual functions of the two patients with Landau-Kleffner syndrome were normal; however, their everyday lives were disrupted by severe, disabling language disturbances. We discuss the role of some prognostic factors such as the location of the interictal electric focus and the age at onset of CSWS.

CONCLUSIONS

These two epileptic syndromes of childhood are very similar in many respects, but their clinical outcomes in adulthood are different.

Sleep and arousal mechanisms in experimental epilepsy: Epileptic components of NREM and antiepileptic components of REM sleep

Neural generators related to different sleep components have different effects on seizure discharge. These sleep-related systems can provoke seizure discharge propagation during nonrapid eye movement (NREM) sleep and can suppress propagation during REM sleep. Experimental manipulations of discrete physiological components were conducted in feline epilepsy models, mostly in the systemic penicillin epilepsy model of primary generalized epilepsy and the amygdala kindling model of the localization-related seizure disorder, temporal lobe epilepsy. The sleep-wake state distribution of seizures was quantified before and after discrete lesions, systemic and localized drug administration, and/or photic stimulation, as well as in relation to microdialysis of norepinephrine. We found that (1) neural generators of synchronous EEG oscillations--including tonic background slow waves and phasic "arousal" events (sleep EEG transients such as sleep spindles and k-complexes)--combine to promote electrographic seizure propagation during NREM and drowsiness, and antigravity muscle tone permits seizure-related movement; (2) neural generators of asynchronous neuronal discharge patterns reduce electrographic seizures during alert waking and REM sleep, and skeletal motor paralysis blocks seizure-related movement during REM; (3) there are a number of similarities between amygdala-kindled kittens and children with Landau-Kleffner Syndrome (LKS) that suggest a link among seizures, sleep disorders, and behavioral abnormalities/regression.

Landau-Kleffner syndrome, electrical status epilepticus in slow wave sleep, and language regression in children

The Landau-Kleffner syndrome (LKS) and electrical status epilepticus in slow wave sleep (ESES) are rare childhood-onset epileptic encephalopathies in which loss of language skills occurs in the context of an epileptiform EEG activated in sleep. Although in LKS the loss of function is limited to language, in ESES there is a wider spectrum of cognitive impairment. The two syndromes are distinct but have some overlap. The relationship between the epileptiform EEG abnormalities and the loss of cognitive function remains controversial, even in LKS which is the most widely accepted as an acquired epileptic aphasia. Language regression also occurs in younger children, frequently in the context of a more global autistic regression. Many of these children have epileptiform EEGs. The term autistic regression with epileptiform EEG has been proposed for these children. Whether these children are part of an extended LKS spectrum is very controversial, because there are differences in age of onset, clinical phenotype, and EEG findings. An understanding of the available data on clinical characteristics, EEG findings, pathology, prognosis, and treatment of these syndromes is essential for further progress in this area.

Epileptic Encephalopathy of Late Childhood

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.

Phonological short-term memory networks following recovery from Landau and Kleffner syndrome

Landau-Kleffner syndrome (LKS) is a rare acquired aphasia occurring in otherwise healthy children, together with spike-wave discharges predominating over superior temporal regions and activated by sleep. Although the outcome of language abilities is variable, a residual impairment in verbal short-term memory (STM) is frequent. This STM deficit might be related to the persistent dysfunction of those temporal lobe regions where epileptic discharges were observed during the active phase of the disorder. We tested this hypothesis by measuring brain activation during immediate serial recall of lists of 4 words, compared to single word repetition, using H(2) (15)O positron emission tomography (PET), in 3 LKS patients after recovery and in 14 healthy controls. The patients (TG, JPH, and DC) had shown abnormally increased or decreased glucose metabolism in left or right superior temporal gyrus (STG) at different stages during the active phase of their disease. At the time of this study, the patients were 6-10 years from the active phase of LKS. Results showed that Patients JPH and DC had impaired performance in the STM condition, whereas TG showed near normal performance. PET data showed that JPH and DC activated significantly less than controls left and right posterior STG. TG, having near normal STM performance, showed increased activity in the posterior part of the right STG. These data suggest that impaired verbal STM at late outcome of LKS might indeed be related to a persistent decrease of activity in those posterior superior temporal gyri that were involved in the epileptic focus during the active phase.

[Landau-Kleffner syndrome (acquired epileptic aphasia)]

Landau-Kleffner syndrome is characterized by a complex group of symptoms including deterioration in language skills, seizures, and abnormal electroencephalography findings. A six-year-old male patient had aphasia for three years and generalized tonic-clonic epileptic seizures for two years. Pure-tone audiometry and auditory brain-stem response audiometry findings were normal. He had verbal auditory agnosia rather than true aphasia. Cranial computed tomography and magnetic resonance imaging studies did not show any abnormal findings. Single-photon emission computed tomography showed hypoperfusion in the right hemispheric temporal lobe. Despite treatment with corticosteroids and intravenous immunoglobulins, multiple exacerbations were interspersed in a four-year follow-up period.

[Electroclinical characteristics of Landau-Kleffner syndrome]

The study aimed at investigating epileptic attack's semiology and other electroclinical characteristics in Landau-Kleffner syndrome as well as therapeutic efficacy. Six patients with Landau--Kleffner syndrome, 5 boys, 1 girl, aged 6-10 years, mean age 7.5 years, have been analyzed. Epileptic attacks were observed only in 3 patients with debut at the age of 2.5-6 years (mean 4 years). In 50% of the cases, the attacks were not detected. The types of epileptic attacks were specified as follows: atypical absences--3 patients; pharyngo-oral--2; secondary generalized--2; atonic falls--1; hemiconvulsive--1. In routine EEG study, regional epileptiform activity was observed in all the patients, being localized in central temporal (3 cases), posterior temporal (1) and fronto-temporal (1) leads. In 3 cases (50%), diffusive epiactivity was also detected. During sleep, emergence of prolonged diffuse epiactivity was revealed for all the patients, with appearance of electrical status epilepticus during slow sleep in 50%. Valproates in dosage 30-60 mg/kg daily were highly effective for stopping epileptic seizures. Significant improvement of speech functions was observed only if antiepileptics sulthiame (ospolot) or clobasam (frizium) were used in addition to basic therapy. Clobasam in dosage 0.5-0.75 mg/kg daily was the most efficient in blockade of EEG diffuse epileptiform activity, reduction of aphasia symptoms and behavior improvement.

Effect of sleep on epilepsy

There is an extremely intimate relationship between sleep and epilepsy. In this manuscript I will review the influence that sleep has on epilepsy. Sleep is a potent activator of interictal epileptiform discharges. Sharp waves are infrequent during wakefulness in benign focal epilepsy of childhood, but may occur in runs of several discharges per page in sleep. The interictal discharges become almost continuous in non-REM sleep in the syndrome of encephalopathy with electrical status epilepticus during slow wave sleep. In some patients with West syndrome a hypsarrhythmia pattern may only appear in sleep whereas in others there may be an increase in discharges in a semiperiodic fashion resulting in a burst-suppression like pattern. Seizures appear to have a very close relationship with sleep in certain epilepsy syndromes. In benign focal epilepsy of childhood the seizures occur almost exclusively in sleep, while supplementary sensorimototor area seizures tend to occur in clusters during sleep. Juvenile myoclonic epilepsy has a close relationship with the sleep-wake cycle with seizures tending to occur predominantly on awakening. I also discuss the role of sleep and sleep deprivation in the EEG evaluation of epilepsy.

The Landau-Kleffner syndrome

Landau-Kleffner Syndrome is a rare childhood disorder which involves seizures and acquired aphasia. Anticonvulsants, or the passage of time, may control the seizures, but speech recovery is variable, and the aphasia may persist.

Landau-Kleffner syndrome beginning with stuttering: case report

Landau-Kleffner syndrome is marked by an acquired aphasia in children who have had normal language and motor development. A 3.5-year-old girl was referred to our clinic with stuttering. She was diagnosed as having benign myoclonic epilepsy of infancy at 3.5 months of age and treated with valproic acid. Her electroencephalogram (EEG) returned to normal at the end of the first year. The therapy was stopped after a 2-year seizure-free period. She started to stutter prominently 3 months after the discontinuation of antiepilepsy drugs. She had no verbal agnosia. Her EEG revealed multiple spike and wave discharges. She was diagnosed as having Landau-Kleffner syndrome. Her previous epilepsy history had contributed to her having obtained an EEG in the early period. We suggest that if a child with normal language function starts to stutter, Landau-Kleffner syndrome must be considered in the differential diagnosis.

Characteristics of the epilepsies

Epilepsy is not a specific disease but rather a heterogeneous group of disorders that have in common the characteristic of recurrent, usually unprovoked seizures. Epileptic seizures represent the intermittent and self-limited clinical manifestations (signs and symptoms) that result from abnormally excessive and synchronous activity of neurons. Seizures are categorized as partial (with the initial activation of a limited number of neurons in a part of 1 hemisphere) or generalized (with the initial activation of neurons throughout both hemispheres). Epilepsy, however, is more than just recurrent seizures. It includes a specific etiology, associated neurologic abnormalities, a genetic background, environmental factors, responses to various therapies, and other factors. The disability and the effect on quality of life may be different for each individual. A variety of epileptic conditions have associated clinical and electroencephalographic (EEG) features that can be categorized as syndromes. Many of the syndromes have different etiologies in different patients yet share common characteristics such as the age at seizure onset; seizure type(s); intellectual development; and findings on neurologic examinations, EEGs, and neuroimaging. The epilepsies are categorized into 3 groups (idiopathic, cryptogenic, and symptomatic) on the basis of the presumed etiologies. Understanding the characteristics of the epilepsy syndromes provides a powerful tool for the prognosis and treatment of individuals experiencing seizures. In this article, we discuss characteristic features of the epilepsies.

Acquired epileptiform aphasia: a dimensional view of Landau-Kleffner syndrome and the relation to regressive autistic spectrum disorders

Acquired epileptiform aphasia (AEA) is characterized by deterioration in language in childhood associated with seizures or epileptiform electroencephalographic abnormalities. Despite an extensive literature, discrepancies and contradictions surround its definition and nosological boundaries. This paper reviews current conceptions of AEA and highlights variations in the aphasic disturbance, age of onset, epileptiform EEG abnormalities, temporal course, and long-term outcome. We suggest that AEA, rather than being a discrete entity, is comprised of multiple variants that have in common the features of language regression and epileptiform changes on EEG. Viewed this way, we argue that AEA can be conceptualized on a spectrum with other epileptiform neurocognitive disorders that may share pathophysiological features. The implications of this viewpoint are discussed, with emphasis on parallels between the AEA variants and regressive autistic spectrum disorders.

The use of immunoglobulins in the treatment of human epilepsy

The use of immunoglobulin (IVIg) in intractable epilepsy is one of its oldest applications in medicine, starting from the empirical observation of its beneficial effect on seizures. Immune system dysfunction may play a role in epilepsy by triggering, maintaining or, unexpectedly, improving intractable seizures. Several laboratory and clinical investigations are in favor of an immunological basis for different forms of experimental and human epilepsies. A wide range of immune abnormalities have been reported, suggesting the existence of different subtypes of epileptic syndromes with different abnormalities of the immune system. In this view, IVIg with its broad immunomodulatory mechanism of action could be effective in different forms of immune-dysregulated intractable epilepsies. Non-immunological mechanisms of action have been also suggested, based either on human epilepsy data or on animal experimental data. The possible anticonvulsant properties and the ability of IVIg to interfere with the final common pathway of seizures at a cellular level, with a significant increase in seizure threshold, have been demonstrated in different experimental epilepsy model. Although IVIg may represent a valuable resource in some drug-refractory epilepsies and its effectiveness has important pathogenetic implications, controlled studies with the systematic monitoring of immunological markers are needed to define more precise indications and to optimize the administration protocols.

Efficacy of intravenous immunoglobulin in Landau-Kleffner syndrome

We administered 2 gm/kg of intravenous gamma globulin (IVIG) to each of five consecutive patients with Landau-Kleffner syndrome, over 4 days. We compared the 1-month baseline to that following IVIG using a severity score assessing speech, comprehension, behavior, seizures, and electroencephalography. There was a significant drop in this score after IVIG (P = 0.025). Two patients had a dramatic response to IVIG, with complete resolution of symptoms. This finding suggests that IVIG has at least some efficacy for the therapy of Landau-Kleffner syndrome.

[Landau kleffner syndrome]

INTRODUCTION

The Landau Kleffner syndrome (SLK) is associated with paroxystic alterations of the electroencephalogram which are intensified during sleep, with acquired aphasia and epilepsy, in 75 83% of the cases. The syndrome is associated with other features, such as personality disorders presenting as autistic behaviour, cognitive regression and in some cases, motor dysfunction. The epileptic activity appears to be responsible for the disorder. Treatment with anti epileptic drugs is ineffective in many cases, although there may be periods of spontaneous improvement, or there may be permanent sequelas of language. Design. A systematic revision of one case.

CASE REPORT

A five year old boy with no previous clinical history had, at the age of four years, presented with behaviour changes and aphasia, accompanied by paroxystic changes on the EEG and nocturnal polysomnogram. On cranial CT there was a mid line cyst. He had had no seizures. Treatment. Treatment with carbamazepine led to clinical improvement in behaviour, reduction in the paroxysms and appearance of sleep spindles, but little effect on the degree of aphasia.

CONCLUSIONS

The case described is a variant of SLK, with no epileptic seizures, some improvement on carbamazepine and a mid line cyst.

The relationship between sleep and epilepsy

Seizures occur extensively during sleep or on awakening in a substantial proportion of patients with epilepsy. Interictal epileptiform discharges are also influenced by sleep and sleep deprivation. Continuous spike-waves in slow-wave sleep are the hallmark of Landau-Kleffner syndrome and ESES (Electrical Status in Slow Sleep). Sleep deprivation is known to influence not only the occurrence but also the symptomatology of epileptic seizures. Sleep architecture and daytime alertness are influenced by seizures and antiepileptic medications. This review examines the clinical and basic science aspects of this relationship between sleep and epilepsy.

Short-term memory impairment and unilateral dichotic listening extinction in a child with Landau-Kleffner syndrome: auditory or phonological disorder?

The neuropsychological profile of a child with a Landau-Kleffner syndrome is presented here. The observed cognitive difficulties included verbal short-term memory and seemed partially compensated for when the experimental assessments bypassed the auditory channel. This case study is especially challenging since the child, whose phonological skills were quite efficient and who exhibited a dichotic listening unilateral extinction, had developed average reading and spelling abilities. The fact that B.E.'s performance on memory tasks was quite poor when the stimuli were presented auditorily and more efficient when the stimuli were presented visually, strongly suggests that the observed memory impairment was due to a deficit at the level of cortical auditory processing. B.E.'s phonological skills were efficient, suggesting a neuropsychological dissociation between phonological ability and auditory processing. The fact that B.E. dramatically recovered language and easily acquired reading and spelling accounts for the hypothesis that compensatory strategies allowed him to develop phonological skills from predominantly visual input.

Accessibility of spoken, written, and sign language in Landau-Kleffner syndrome: a linguistic and functional MRI study

Landau-Kleffner syndrome (LKS) is an acquired aphasia which begins in childhood and is thought to arise from an epileptic disorder within the auditory speech cortex. Although the epilepsy usually subsides at puberty, a severe communication impairment often persists. Here we report on a detailed study of a 26-year old, left-handed male, with onset of LKS at age 5 years, who is aphasic for English but who learned British Sign Language (BSL) at age 13. We have investigated his skills in different language modalities, recorded EEGs during wakefulness, sleep, and under conditions of auditory stimulation, measured brain stem auditory-evoked potentials (BAEP), and performed functional MRI (fMRI) during a range of linguistic tasks. Our investigation demonstrated severe restrictions in comprehension and production of spoken English as well as lip-reading, while reading was comparatively less impaired. BSL was by far the most efficient mode of communication. All EEG recordings were normal, while BAEP showed minor abnormalities. fMRI revealed: 1) powerful and extensive bilateral (R > L) activation of auditory cortices in response to heard speech, much stronger than when listening to music; 2) very little response to silent lip-reading; 3) strong activation in the temporo-parieto-occipital association cortex, exclusively in the right hemisphere (RH), when viewing BSL signs. Analysis of these findings provides novel insights into the disturbance of the auditory speech cortex which underlies LKS and its diagnostic evaluation by fMRI, and underpins a strategy of restoring communication abilities in LKS through a natural sign language of the deaf (with Video)

Atypical semiology of rolandic epilepsy in some related syndromes

Atypical seizures, especially generalized or focal atonic attacks and atypical absences may occur in association with the classical seizures of rolandic epilepsy. They are often associated with unusual EEG features, especially a marked activation of paroxysms during sleep that may amount to continuous spike-wave complexes of slow sleep. These electroclinical features are often accompanied by cognitive and/or behavioral disturbances and may belong to several syndromes (atypical benign partial epilepsy, syndrome of continuous spike-waves during sleep, Landau-Kleffner syndrome and status of rolandic epilepsy) whose relationship with typical rolandic epilepsy and among themselves remains to be clarified.

Multiple subpial transection in Landau-Kleffner syndrome

We have considered multiple subpial transection (MST) as a treatment option for Landau-Kleffner syndrome (LKS) for the past 6 years. The effect of this technique on language and cognitive ability, behaviour, seizures, and EEG abnormalities is analysed here. Five children (4 males, 1 female; aged 5.5 to 10 years) underwent MST with sufficiently detailed pre- and postoperative data for analysis. Behaviour and seizure frequency improved dramatically after surgery in all children. Improvement in language also occurred in all children, although none improved to an age-appropriate level. All five had electrical status epilepticus in sleep (ESES) before surgery, which was eliminated by the procedure. One child has had an extension of his MST due to the recurrence of ESES and accompanying clinical deterioration with good effect. An attempt is made to set the effect of MST against the natural history of the condition. MST is an important treatment modality in LKS, although the timing of this intervention and its effect on final language outcome remains to be defined.