Acquired aphasia, dementia, and behavior disorder with epilepsy and continuous spike and waves during sleep in a child

22q11.2 Microduplication syndrome and epilepsy with continuous spikes and waves during sleep (CSWS). A case report and review of the literature

Chromosome 22q11.2 microduplication syndrome is characterized by a variable and usually mild phenotype and by incomplete penetrance. Neurological features of the syndrome may entail intellectual or learning disability, motor delay, and other neurodevelopmental disorders. However, seizures or abnormal EEG are reported in a few cases. We describe a 6-year-old girl with microduplication of chromosome 22q11.2 and epilepsy with continuous spikes and waves during sleep (CSWS). Her behavioral disorder, characterized by hyperactivity, impulsiveness, attention deficit, and aggressiveness, became progressively evident a few months after epilepsy onset, suggesting a link with the interictal epileptic activity characterizing CSWS. We hypothesize that, at least in some cases, the neurodevelopmental deficit seen in the 22q11.2 microduplication syndrome could be the consequence of a disorder of cerebral electrogenesis, suggesting the need for an EEG recording in affected individuals. Moreover, an array-CGH analysis should be performed in all individuals with cryptogenic epilepsy and CSWS.

Continuous spike and waves during sleep and electrical status epilepticus in sleep

Continuous spike and waves during sleep is an age-related epileptic encephalopathy that presents with neurocognitive regression, seizures, and an EEG pattern of electrical status epilepticus during sleep. Patients usually present around 5 years of age with infrequent nocturnal unilateral motor seizures that progress within 1 to 2 years to a severe epileptic encephalopathy with frequent seizures of different types, marked neurocognitive regression, and an almost continuous spike-wave EEG pattern during slow-wave sleep. The pathophysiology of continuous spike and waves during sleep is not completely understood, but the corticothalamic neuronal network involved in physiologic oscillating patterns of sleep is thought to be switched into a pathologic discharging mode. Early developmental injury and/or genetic predisposition may play a role in the potentiation of age-related hyperexcitability in the immature brain. A better understanding of the mechanisms leading to electrical status epilepticus during sleep may provide additional therapeutic targets that can improve the outcome of seizures, EEG pattern, and cognitive development in patients with continuous spike and waves during sleep.

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.

Regression in autistic spectrum disorders

A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both. This paper critically reviews the phenomena of regression in autistic spectrum disorders, highlighting the characteristics of regression, age of onset, temporal course, and long-term outcome. Important considerations for diagnosis are discussed and multiple etiological factors currently hypothesized to underlie the phenomenon are reviewed. It is argued that regressive autistic spectrum disorders can be conceptualized on a spectrum with other regressive disorders that may share common pathophysiological features. The implications of this viewpoint are discussed.

Epileptic syndromes in infancy and childhood

PURPOSE OF REVIEW

The aim of this article is to review new epilepsy syndromes, acquire a new understanding of older ones and emphasize the impact of this concept on basic research regarding aetiology and treatment.

RECENT FINDINGS

In addition to those included in the classification of the International League Against Epilepsy, new epilepsy syndromes comprise febrile seizures plus, benign familial neonatal-infantile seizures (BFNIS), benign infantile focal epilepsy with midline spikes and waves during sleep (BFIS), malignant migrating partial seizures in infancy, devastating epilepsy in school age children and late onset cryptogenic spasms. Genetics played a central role in identifying some new entities (BFNIS, BFIS with choreoathetosis), to delineate older syndromes (Dravet syndrome and myoclonic astatic epilepsy) and determine their mechanisms (infantile spasms, pyridoxine dependent seizures, neonatal encephalopathy with suppression bursts).

SUMMARY

A significant number of children, mainly infants, do not fit in any of the described epilepsy syndromes. Still many patients with infantile epilepsy require the identification of cause or recognition of an epilepsy syndrome.

Cognitive and Behavioral Outcomes of Epileptic Syndromes: Implications for Education and Clinical Practice

The educational and social progress of a child with epilepsy depends not only on seizure control but also on cognitive and behavioral factors. The various epilepsy syndromes of childhood and adolescence differ greatly in terms of cognitive and behavioral outcome. A high proportion of babies who have West syndrome and children who have Dravet syndrome (severe myoclonic epilepsy in infancy) will have long-term cognitive and behavioral problems. The Lennox-Gastaut syndrome also often has a poor prognosis in this regard. Children with the Landau-Kleffner syndrome have a variable prognosis, some regain speech and others have permanent speech impairment. Benign childhood epilepsy with centrotemporal spikes is now recognised as lying on a spectrum with the Landau-Kleffner syndrome: mild cases have few if any cognitive or behavioral problems but others may have quite severe difficulties. People with juvenile myoclonic epilepsy may have characteristics suggesting frontal lobe impairment. The educational and social impairments associated with the epilepsy syndromes of childhood and adolescence are of major importance but they have been the subject of remarkably few well-performed studies. The impairments are not always necessarily permanent and it seems highly likely that the cognitive and behavioural outcome of at least some of these syndromes can be influenced greatly by early effective treatment with either antiepileptic medication or surgery.

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.

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.

Idiopathic epileptic syndromes and cognition

Epilepsy is frequently associated with cognitive impairments which result from various interacting factors. The present paper deals with the contribution of neuropsychology to the characterization of the type of epilepsy and the possible mechanisms underlying idiopathic epileptic syndromes. The non-lesional, so-called idiopathic epilepsies, constitute an interesting model for assessing the relationship between epileptiform EEG discharges and cognition. Among the idiopathic generalized epilepsies, disorders of social integration and personality have been frequently reported in juvenile myoclonic epilepsy (JME). Since similar disturbances are observed in frontal-lobe-lesioned patients, impairments in other frontal lobe functions (e.g. executive functions) might be expected in JME. This gives rise to speculation about the possible underlying pathophysiological mechanisms in JME. With regard to partial idiopathic epilepsies, benign childhood epilepsy with centrotemporal spikes (BCECTS) may provide a useful model for the study of the relationship between epileptiform EEG discharges in the peri-sylvian region and language functions. Furthermore, the description of mild cognitive dysfunctions in BCECTS, and their persistence into adulthood, can provide information about compensatory mechanisms and may allow for the generation of remedial strategies. Thus, 'lesional' neuropsychology has given way to 'dynamic' neuropsychology based on specific postulates. By using the cognitive profile to specify the mechanism underlying the behavioral disturbances observed in different types of epilepsy, neuropsychology may eventually contribute to a revision of the present classification of epileptic syndromes. In addition, the neuropsychological data may help predict the extent and limits of functional recovery and cerebral plasticity.

Cognitive deterioration and electrical status epilepticus during slow sleep

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

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.

Behavioral aspects of pediatric epilepsy syndromes

Apart from control of the seizures, two of the most important factors in determining how well a child with epilepsy progresses toward independence are cognition and behavior. The diagnosis of the correct epilepsy syndrome often provides information with regard to probability of good seizure control and intellectual outcome. However, relatively little has been published on the behavioral aspects of the various epilepsy syndromes. In West syndrome there is emerging evidence that early effective treatment might improve outcome in terms of both cognition and behavior. The work on this syndrome in children with tuberous sclerosis has demonstrated an association between temporal lobe tubers and autism. In Dravet syndrome, a variety of psychiatric disorders have been reported, including hyperactivity and autistic features. This is another epilepsy syndrome that tends to be resistant to treatment, implying that the prognosis has to be guarded. The behavioral problems reported with Lennox-Gastaut syndrome also include autistic features, as well as generally sluggish behavior. It is very likely that these characteristics largely reflect the effect of ongoing seizure activity. Autistic features, aggression, and hyperkinesis have been described with Landau-Kleffner syndrome. The behavior may improve dramatically with appropriate medical treatment or after multiple subpial transection. Although the syndrome of benign partial seizures with centrotemporal or rolandic spikes is said to have a very good prognosis, it is becoming increasingly evident that behavioral problems such as concentration difficulties, tempers, hyperactivity, and impulsivity might occur. Juvenile myoclonic epilepsy has been associated with very variable behavioral traits, sometimes with immature personality features and poor social adjustment suggesting frontal lobe dysfunction. Because many of the reports of behavioral disturbance associated with epilepsy syndromes are anecdotal and do not include validated measures of behavior it would be unwise to draw firm conclusions from them at this stage. Carefully conducted prospective studies, paying particular attention to any behavioral improvements that occur with successful treatment of the epilepsy, are required.

Effects of epileptiform EEG discharges on cognitive function: is the concept of "transient cognitive impairment" still valid?

In this article we review the existing evidence on the cognitive impact of interictal epileptiform EEG discharges. Such cognitive impairment occurs exclusively in direct relation to episodes of epileptiform EEG discharges and must be distinguished from (post) ictal seizure effects and from the nonperiodic long-term "stable" interictal effects caused by the clinical syndrome or the underlying etiology. Especially in patients with short nonconvulsive seizures, characterized often by difficult-to-detect symptoms, the ictal or postictal effects may be overlooked and the resulting cognitive effects may be erroneously related to the epileptiform EEG discharges. The existing epidemiological data show that the prevalence of cognitive impairment during epileptiform EEG discharges is low. In one study 2.2% of the patients referred to a specialized epilepsy center for EEG recording showed a definite relationship between epileptiform EEG discharges and cognitive impairments ("transient cognitive impairment"). Several studies have sought to analyze to what extent cognitive impairment can be attributed to epileptiform EEG discharges among the other epilepsy factors (such as the effect of the clinical syndrome). These studies show that epileptiform EEG discharges have an additional and independent effect, but this effect is mild and limited to transient mechanistic cognitive processes (alertness, mental speed). This finding concurs with clinical studies that also reported only mild effects. In only exceptional cases are epileptiform EEG discharges the dominant factor explaining cognitive impairment. In addition, some studies have indicated that such mild effects may accumulate over time (when frequent epileptiform EEG discharges persist over years) and consequently result in effects on stable aspects of cognitive function such as educational achievement and intelligence. Hence, the clinical relevance is that early detection of cognitive effects of epileptiform EEG discharges and subsequent treatment may prevent a definite impact on cognitive and educational development. The disruptive effects of epileptiform EEG discharges on long-term potentiation, as established in animal experiments, may be one of the neurophysiological mechanisms underlying this accumulation. In conclusion the concept of "transient cognitive impairment" is still valid, but refinement of methodology has shown that a large proportion of presumed transient cognitive impairment can be attributed to subtle seizures, while interictal epileptic activity accounts for a much smaller part of the cognitive effects than previously thought. In particular cryptogenic partial epilepsies are associated with the risk of cognitive impairment. We hope that increased clinical awareness of this need for early detection will stimulate longitudinal and prospective research that eventually also will provide an answer to the questions of when and how epileptiform discharges that are not part of a seizure need to be treated.

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.

Acquired epileptic frontal syndrome as long-term outcome in two children with CSWS

Continuous spikes and waves during slow sleep (CSWS) are a well-known EEG pattern that can be associated with cognitive and behavioural deterioration. We present the long-term clinical, neuropsychological and EEG follow-up of two patients who developed CSWS during childhood. In both the CSWS onset was followed immediately by rapid cognitive and behavioural deterioration. Later the CSWS fragmented or fluctuated and the spike-wave discharges diminished and this was associated with progressive clinical improvement. At the same time bilateral frontal EEG abnormalities appeared awake and in sleep. After the initial period of rapid cognitive and linguistic improvement both patients stabilised. The latest neuropsychological assessment showed a frontal syndrome. The presence of frontal EEG abnormalities superimposed on CSWS, their persistence after CSWS resolution and, in addition, the finding of subtle frontal-type neuropsychological alterations early in recovery may indicate poor long-term outcome.

Interactions between sleep and epilepsy

Sleep is one of the best-documented factors influencing the expression of seizures and interictal discharges. Janz studied the relation between seizures and the sleep/wake cycle and divided the epilepsies into three categories: nocturnal, awakening, and diffuse. Since then, the effect of sleep on the ictal and interictal manifestations of epilepsy has been studied extensively. Many seizures are activated by sleep or arousal from sleep. Interictal discharges are also seen more commonly during sleep, with the greatest activation seen during nonrapid eye movement sleep. Sleep not only increases the frequency of epileptiform abnormalities, but also may alter their morphology and distribution. Sleep deprivation also facilitates both epileptiform abnormalities and seizures. Seizures, on the other hand, also impact sleep. Epileptic patients demonstrate multiple sleep abnormalities, including an increased sleep latency, fragmented sleep, increased awakenings and stage shifts, and an increase in stages 1 and 2 of nonrapid eye movement sleep. These disturbances may in turn be modulated by antiepileptic treatment. This review summarizes the interactions between sleep and epilepsy, including the timing of seizures during the sleep/wake cycle, the influence of sleep on various seizure disorders, the effects of sleep deprivation, and the changes in sleep patterns caused by seizures and their treatment.

Epilepsy and epileptiform EEG: association with autism and language disorders

The relationship between epilepsy, language, behavior, and cognition is not well understood. Developmental and acquired disabilities such as autistic spectrum disorders, Landau-Kleffner Syndrome, electrical status epilepticus in sleep, and developmental dysphasias have been associated with epileptiform abnormalities. These disorders share many common features and raise important questions regarding this intricate relationship. This article reviews these disorders and discusses the proposed interaction between epileptiform abnormalities and cognitive dysfunction. Diagnostic and treatment issues will also be reviewed.

Spectrum of epileptic syndromes with electrical status epilepticus during sleep in children

There has been much debate about the nosologic forms of electrical status epilepticus during sleep (ESES) that can occur in a number of syndromes. The pathogenesis of ESES is unknown, and the natural course is variable. It is debatable whether these age-specific epileptic syndromes belong to the same spectrum of disorders with different severity but a common denominator of sleep-related hypersynchronization of generalized paroxysmal epileptic discharges. This report describes 18 children with medically refractory seizures, gradual deterioration in language skills, fine-motor incoordination, behavioral changes, psychologic and intellectual regression of different degrees, and the ESES phenomenon. Most exhibited clinical and electroencephalographic responses to intravenous or oral benzodiazepines, especially if initiated within the first 2 years of seizure onset. Seizure remission was nearly complete with cessation of seizures and marked improvement in language and fine-motor skills, behavior, and intellectual function in those with an idiopathic etiology. Therapeutic trials with benzodiazepines should be given to all children with the ESES phenomenon. Sleep electroencephalographic monitoring is recommended in all young children with epilepsy and language or psychologic deterioration so that the brain dysfunction can be reversed at a critical and vulnerable period of early life.

Is ESES/CSWS a strictly age-related disorder?

OBJECTIVES

We report on a case of ESES/CSWS observed in a patient of 21 years and still persisting at the age of 25. Cases of ESES/CSWS have never been previously described in adult patients. ESES/CSWS is considered to be related to the degree of maturation of the central nervous system, and therefore strictly age-related.

METHODS

Our case of ESES/CSWS was observed in a 2 1 year old woman referred for cognitive and behavioral disorders. She had previously had epileptic fits, but was seizure free at that time. The patient underwent a full-night polygraphic recording , which showed typical ESES/CSWS pattern, with a Spike-and-Wave Index >8 5%. Polysomnography was repeated 9 times in a 4 year follow-up, during which the ESES/CSWS condition persisted, despite the pharmacological treatments. The patient also underwent cerebral magnetic resonance imaging and fludeoxyglucose F 18 positron emission tomography (PET).

RESULTS

The PET study revealed reduced metabolic activity within the lower gyrus of the right parietal lobe, but no significant difference between subcortical structures and cortical mantle was seen. MRI scans were normal.

CONCLUSIONS

This observation suggests that ESES/CSWS might not always be an age-related condition. Sleep EEG recordings should always be performed in patients with behavioral disorders and a history of epileptic fits.

The influence of premorbid language skills and behavior on language recovery in children with verbal auditory agnosia

Previous studies of children with Landau-Kleffner syndrome and related language-epilepsy syndromes have focused on the relationship of seizure control to language recovery. We examined the effect of premorbid language skills and behavior, as well as some characteristics of clinical seizures and electroencephalograms, on language recovery in a retrospective study of 67 children with the severe receptive and expressive language disorder, verbal auditory agnosia. Fifty-eight percent of these children had seizures, 76% were autistic, and 24% had a history of language regression after showing previously normal language skills. The duration of language loss was not influenced by the persistence of clinical seizures. Premorbid language and behavior were more predictive of language recovery in these children. Most children with normal early language (acquired verbal auditory agnosia) had onset of language loss after age 3 years, in contrast to those with abnormal early language. Children with acquired verbal auditory agnosia were more likely to show fluctuations in language skills than those in other groups. Autistic children were more likely to begin having seizures before age 3 years, and had a longer duration of language loss and lower educational placement at time of last follow-up than those with normal behavior. This study emphasizes the importance of assessing premorbid language and behavior in predicting recovery of language skills in children with language-epilepsy syndromes.

Treatment of acquired epileptic aphasia with the ketogenic diet

Acquired epileptic aphasia remains a poorly understood entity, which is frequently difficult to treat. Previously described treatment modalities have included antiepileptic drugs, corticosteroids, intravenous immunoglobulin, and multiple subpial transections. We describe three patients with acquired epileptic aphasia refractory to traditional treatments who were successfully treated with the ketogenic diet. All three patients had lasting improvement of their language, behavior, and seizures for 26, 24, and 12 months, respectively. This is the first reported series of patients with acquired epileptic aphasia successfully treated with the ketogenic diet, and suggests a new therapeutic alternative for patients with this often difficult-to-treat disorder.

Continuous spike-waves during slow waves sleep. A clinical and electroencephalographic study in fifteen children

We report on the clinical and EEG features of 15 patients with the syndrome of "continuous spike waves during slow wave sleep" (CSWSS). The differential diagnosis of CSWSS includes benign epilepsy of childhood with centro-temporal spikes, and Landau-Kleffner and Lennox-Gastaut syndromes. We found normal CT and MRI features in 6 cases, periventricular leukomalacia with and without diffuse brain atrophy in 4 cases and hydrocephalus in 1 case. There was no association between specific neurological findings and CSWSS. Nine of our cases had relatively focal discharges, like some cases from the literature. The occurrence of CSWSS appears to be age-related, generally between the ages of 5 to 12 years, with a strong temporal relation to the neuropsychological deterioration in its nature, severity and prognosis. We believe that this striking disorder has been overlooked and that routine sleep EEG studies on epileptic children may disclose additional cases of CSWSS.

Outcome of multiple subpial transections for autistic epileptiform regression

Treatment options for atypical forms of Landau-Kleffner syndrome (LKS) are not well delineated. Many patients with typical LKS fail to respond to antiepileptic drug treatment, but some benefit from multiple subpial transections (MSTs). The authors report seven patients with autism or autistic epileptiform regression who responded in varying degrees to MSTs after failed medical management. These patients derived from an original cohort of 36 children (29 males, seven females, ranging from 2 years, 3 months to 11 years, 3 months, mean age = 5 years, 8 months) with a history of language delay or regression, as well as varying degrees of social and behavioral abnormalities, who were evaluated with video-electroencephalogram (EEG) monitoring over a 2-year period. Fifteen patients had clinical seizures (11 of the 19 children with autistic epileptiform regression and four of 12 autistic children). Epilepsy was refractory to medication in seven. Surgical treatment variously involved MSTs of the left neocortex in temporal, parietal, and frontal regions, often including regions within the classic perisylvian language areas. One patient also had a left temporal lobectomy. In all seven patients, seizure control or EEG improved after MSTs. Language, social, and overall behavior improved to a moderate degree, although improvements were temporary in most. Autistic epileptiform regression resembles LKS in that both may respond to MST. MST is used to treat epilepsy in eloquent regions. The responsiveness of autistic epileptiform regression to MST buttresses the argument that autistic epileptiform regression is a form of focal epilepsy.

Autism and autistic epileptiform regression with occipital spikes

The electroencephalographic abnormalities seen in Landau-Kleffner syndrome (LKS) (language deterioration) are non-specific, and consist of a variety of epileptiform discharge patterns including continuous slow spike-wave discharges during sleep, focal sharp waves with spikes, and centrotemporal (rolandic) spikes. Similarly, the EEG abnormalities seen in autistic epileptiform regression (language and social/behavioral deterioration) are non-specific and overlap with those seen in LKS. By contrast, distinct epilepsy syndromes in otherwise normal children occur in the EEG-defined benign focal epilepsies of childhood. Occipital spikes or spike-wave present either in the older child with visual symptoms and headache or in the younger child with autonomic symptoms followed by brief or prolonged partial motor seizures. Seven young children (five from a consecutive series of 42) presenting clinically with autism or autistic regression and possible or definite seizures, whose EEGs revealed occipital spikes or spike-wave characteristic of the benign epilepsies, are reported. Although occipital spikes are commonly seen in young children as an age-dependent EEG-defined benign focal epilepsy, their high frequency in this population with cognitive difficulties suggests a possible causal relation. The effects of the epileptiform discharge on cognitive functioning presumably reflect extension into temporal and parietal lobes, rather than occipital disturbances per se.

Antiepileptic drugs and atypical evolution of idiopathic partial epilepsy

Six patients with classic benign epilepsy of childhood with centrotemporal spikes, treated with carbamazepine (four patients) or sodium valproate (two patients) evolved atypically because the epileptic disorder, diffusion of the electroencephalographic (EEG) discharges during wakefulness, and continuous spike-and-wave during slow sleep associated with severe neuropsychologic abnormalities worsened. These features appeared after a seizure-free interval varying for 2 weeks to 1 year 6 months after initiating therapy and remitted when the previous anticonvulsant drug was discontinued and either substituted with another drug or the patient was left without any treatment. Once the initial antiepileptic drug was discontinued and after a period roughly proportional to the duration of the clinical-EEG complication, the evolution of the patients' seizures was not unusual for this type of epilepsy, with patients eventually becoming free of both seizures and medication and reaching normal school achievement. The clinical complications cannot be attributed solely to the drugs. It must also be related to the underlying substract (i.e., the specific epileptic syndrome involved) that in some patients becomes susceptible to atypical evolution when either product is administered.

Electroencephalogram in developmental delay: specific electroclinical syndromes

The electroencephalogram (EEG) plays an important role in the evaluation of a child with developmental delay. An EEG is often required to classify seizures in children with developmental delay. Equally important is the role of the EEG in the identification of specific electroclinical syndromes in children who may or may not manifest seizures. Specific electroclinical syndromes include the acquired epileptiform aphasia syndrome, Landau-Kleffner syndrome, and electrical status epilepticus during slow wave sleep. Other clinical situations where the EEG offers diagnostic and prognostic information, such as subacute sclerosing encephalitis, progressive myoclonus epilepsies, Rett syndrome, and Lennox Gastaut syndrome are also discussed.

Childhood epilepsy with neuropsychological regression and continuous spike waves during sleep: epilepsy surgery in a young adult

We describe the case of a man with a history of complex partial seizures and severe language, cognitive and behavioural regression during early childhood (3.5 years), who underwent epilepsy surgery at the age of 25 years. His early epilepsy had clinical and electroencephalogram features of the syndromes of epilepsy with continuous spike waves during sleep and acquired epileptic aphasia (Landau-Kleffner syndrome), which we considered initially to be of idiopathic origin. Seizures recurred at 19 years and presurgical investigations at 25 years showed a lateral frontal epileptic focus with spread to Broca's area and the frontal orbital regions. Histopathology revealed a focal cortical dysplasia, not visible on magnetic resonance imaging. The prolonged but reversible early regression and the residual neuropsychological disorders during adulthood were probably the result of an active left frontal epilepsy, which interfered with language and behaviour during development. Our findings raise the question of the role of focal cortical dysplasia as an aetiology in the syndromes of epilepsy with continuous spike waves during sleep and acquired epileptic aphasia.

[Continuous spike-wave activity during sleep. Electroencephalographic and clinical features]

Seventeen children were retrospectively evaluated. They exhibited continuous spike-wave activity during slow wave sleep (CSWS). Five of these had only speech problems and seizures (Landau-Kleffner syndrome) (group 1). The other cases had developmental milestones acquisition delay and/or mental retardation (group 2). Epileptic seizures were present in 11 of these, tetraparesis was observed in 5, hemiparesis in 2, microcephaly in 2 and behavior disturbances in 4 cases. The electroencephalogram showed in all cases diffuse CSWS. Group 1 showed diffuse activity, at times accentuated in the centrotemporal region (4/5). Group 2 had widespread discharges, including multifocal activity (5/12), sometimes with anterior predominance (7/12). We concluded that CSWS is a non specific electrographic pattern observed in some types of epilepsy in childhood that have different clinical presentation. It has however some topographic differentiation, depending upon the lesional sites.

The Landau-Kleffner syndrome: increased understanding

The Landau-Kleffner and the continuous spike and wave discharges during slow sleep (CSWS) syndromes are described and possible links between the two are discussed. They certainly overlap, with clinical and electroencephalographic features in common. Potential causes are discussed. There is seldom a definite reason for the seizures but it way well be that the spike and wave discharges seen in the EEG, whatever their origin, may disrupt the development of language and cognitive function at a critical stage. If neurons and axons are involved in this disorganized activity they surely cannot perform normally. The evidence that these discharges in the Landau-Kleffner syndrome can have a focal origin in areas important for language supports this hypothesis. Certain variations among studies quoted may be due to factors such as age of onset, the duration of the paroxysmal activity, its intensity and especially its localization. Also, if development has been distorted subsequent progress is likely to be disturbed after the primary condition has ceased to exist. The diagnosis can sometimes present difficulties, for example from deafness, psychiatric condition, post-ical dysphasia and from progressive degenerative neurological disorders. If the possible role of the epileptic activity is accepted, there are strong reasons for advocating anti-epileptic treatment, even if overt seizures are rare. The response to drugs is varied. Fits will usually stop, but not so often the spike and wave discharges, and it is justifiable to try various regimes. Subpial resection has been reported to be successful, possibly by preventing the cortex generating seizures, and their spread.

Landau-Kleffner syndrome: much more than aphasia and epilepsy

Landau-Kleffner is currently considered a rare syndrome that combines acquired aphasia and epilepsy in children. We present two cases and discuss evidence in the literature that suggest how this syndrome is actually only part of a more generalized situation in which epilepsy (a paroxysmal disorder) produces or is accompanied by a prolonged or permanent derangement of neuronal circuits responsible for higher cortical functions, including language. This reappraisal of the identity of the syndrome could have interesting consequences not only for the study of epilepsy but also for the study of higher cortical functions.

Sleep and the epilepsies

To review the numerous works concerning sleep and epilepsy, this review considers the effects of sleep, firstly on seizures and secondly on paroxysmal interictal EEG activity (PA), in the different types of epilepsy according to the International League against Epilepsy classification. Apart from the exceptions of the definite nocturnal preponderance of seizures in idiopathic rolandic epilepsy and of the mostly nocturnal occurrence of seizures in some types of familial or sporadic frontal-lobe epilepsy, assessing a seizure according to the time of day it occurs is of no diagnostic or predictive value. In generalised idiopathic epilepsy, as in partial symptomatic or cryptogenic epilepsy, only about 20% of the patients had a sleep increase in PA. This percentage is higher (75%) in idiopathic partial epilepsy. Stereoelectroencephalography demonstrates a relative stability of spiking within the focus across the states of vigilance and an increase in transmitted discharges during stages 3 and 4. In the Landau and Kleffner syndrome, as in the syndromes of continuous spike-waves during sleep, there is a huge, unexplained increase in PA during sleep. The neuropsychological consequences of this PA have some relationship with their localisation and the patient's age at the time of occurrence. Sleep PA has also been reported in several groups of non-epileptic subjects. As regards the effect of epilepsy on sleep, sleep may be lighter and abnormally discontinuous in the absence of seizures, particularly in temporal-lobe epilepsy.

Brain single photon emission computed tomography imaging in Landau-Kleffner syndrome

Five right-handed children with Landau-Kleffner syndrome (LKS) who had disease onset between the ages of 3 and 9 years were studied with EEG and single-photon emission computed tomography (SPECT) before and, in four cases, after 6 months of corticosteroid treatment. EEG findings included both focal and generalized spikes as well as spike-wave discharges with bilateral temporal predominance. These increased markedly during sleep in 1 child, and continuous spike-and-wave complexes appeared during slow-wave sleep in another patient. Neuropsychological testing demonstrated verbal auditory agnosia. Magnetic resonance imaging (MRI) was performed in 4 children and was normal. Brain SPECT imaging demonstrated abnormal perfusion in the left temporal lobe in all patients. The response to corticosteroid therapy was mixed. Our findings reinforce the concept that LKS is a functional disease affecting the language-dominant brain areas. We conclude that SPECT imaging may be of diagnostic assistance in the evaluation of this syndrome of unknown etiology.

Autistic regression and disintegrative disorder: how important the role of epilepsy?

At least a third of autistic toddlers regress in language, sociability, play, and often cognition. Many fewer children undergo a similar, unexplained regression after language is fully developed (disintegrative disorder [DD]). Epilepsy or a paroxysmal electroencephalogram (EEG) with/without clinical seizures, including electrical status epilepticus in slow wave sleep (ESES), may be associated, in occasional children, with either selective loss of language (Landau-Kleffner syndrome [LKS]) or with pervasive autistic regression. Fluctuation in language and behavior deficits should raise the suspicion of epilepsy. Review of the literature and of the author's experience suggests that epilepsy probably plays a relatively minor, although non-negligible, pathogenetic role in autistic regression. Multidisciplinary, possibly multi-institutional, longitudinal studies that encompass the regression are needed to sharpen diagnostic criteria to devise more effective therapies.

Syndromes of acquired epileptic aphasia and epilepsy with continuous spike-waves during sleep: models for prolonged cognitive impairment of epileptic origin

Neuropsychological deficits are the common "hallmark" of acquired epileptic aphasia and epilepsy with continuous spike-waves during sleep. Findings from various sources (eg, clinical cases, electrophysiological and positron emission tomography studies) indicate that the aphasia or the behavioral and intellectual deterioration are closely linked to a particular sustained focal epileptic activity. This leads to a wider concept of prolonged cognitive impairment of epileptic origin.

Case study: corticosteroid treatment of language regression in pervasive developmental disorder

The authors describe a child whose language and behavior regressed at 22 months and in whom pervasive developmental disorder was later diagnosed. At 6 years, he displayed a profound receptive-expressive aphasia accompanied by behavioral disturbances characterized by hyperactivity, impaired social interactions, tantrums, gestural stereotypies, and echolalia. A single-photon emission computed tomography scan and steady-state auditory evoked potentials suggested bitemporal and left frontal pathophysiology. The overall profile resembled Landau-Kleffner syndrome, but no electroencephalographic disturbance was evident. Corticosteroid treatment resulted in amelioration of language abilities and behavior. These findings suggest that the factors underlying language regression in pervasive developmental disorder can, in special circumstances, be amenable to pharmacological treatment.

Epilepsy with continuous spike-waves during slow wave sleep: a clinical and electroencephalographic study

We report four children with epilepsy with "continuous spike-waves during slow wave sleep" (CSWSS). The main clinical features were partial motor seizures, mental retardation and motor deficit. The EEG findings were characterized by nearly continuous (> 85%) diffuse slow spike and wave activity in two patients, and localized to one hemisphere in two other cases during non-REM sleep. The treatment was effective in improving the clinical seizures, but not the EEG pattern. We believe that this epileptic syndrome has been overlooked and routine sleep EEG studies on epileptic children may disclose more cases of CSWSS.

SPECT and epilepsy with continuous spike waves during slow-wave sleep

Ten cases of epilepsy with continuous spike waves in slow-wave sleep (CSWS) were evaluated using single photon emission computed tomography (SPECT); in eight patients the EEG paroxysmal abnormalities showed a predominant localization. SPECT carried out using 99mTc-HMPAO allows study of cerebral blood flow (CBF); the examination was performed during phases of drowsiness and the results compared to the EEG data. In four cases SPECT revealed areas of low CBF in sites corresponding to those of the prevalent EEG discharges; in two cases the areas of hypoperfusion did not correspond to those indicated by the EEG; lastly, in four cases SPECT results were negative. The areas of hypoperfusion were predominantly located in the frontal, temporal, and parietal regions. Furthermore, the percentage of positive SPECT results was significantly higher (five cases out of six) in the group in which the CSWS phase was prolonged for at least 1 year, compared to the group in which this phase lasted less than 1 year. Thus, in this type of epilepsy, SPECT reveals focal cortical areas of decreased CBF which correlated generally to the predominant sites of EEG abnormalities. A longer duration of the CSWS phase seems to be associated with a more significant cortical disorder, documented by the presence of areas of hypoperfusion.

[Sleep and intra-ictal epileptic electroencephalographic activities]

From this review it appears that the slow wave sleep (SWS) increases the mean density of electroencephalographic paroxysmal activities (PA) whatever the epileptic syndrome. This pattern is not marked according to a bell curve among the epileptic population: about half the patients exhibit few or no PA during SWS, 20% show an increase during waking and another 20% during SWS. Begnin epilepsy with centro-temporal spikes is associated with an important sleep PA increase. In partial epilepsy, stage 3 and 4 sleep should increase the PA transmission. In children, a large increase in PA during SWS defines the continuous spike-wave during sleep syndrome, which is also observed in the syndrome of acquired aphasia with epilepsy of Landau-Kleffner; both conditions raise the issue of the neuropsychological consequences of the sleep PA. The sleep effect on the various epileptic models is analysed, showing a mean increase in PA during SWS and during transition between sleep and waking. This evidence is in agreement with the fact that during light sleep thalamocortical loops are functioning with an oscillatory pattern which facilitates PA expression. More hypothetic is the effect of sleep on the discharge rate of epileptic focus and on the cortical diffusion of the epileptic discharges. Gaba certainly participates in the thalamic influence, but its role on PA by the cortical and brain stem inhibition is speculative. Noradrenaline and acetylcholine, implicated in waking, reduce PA activity. Interindividual variations suggest that each epileptic has his own pathological neuronal organisation in which cortex and thalamocortical connexions are variously sensitive to the neurotransmitters implicated in sleep and waking.

A correlated fluctuation of language and EEG abnormalities in a case of the Landau-Kleffner syndrome

Despite growing interest in the Landau-Kleffner syndrome there have been few reports dealing with language disorders in recent years. The authors present a clinical case of a child with Landau-Kleffner syndrome focusing particularly on the relationship between language disorders and electroencephalographic abnormalities. The authors emphasize that the language disorders primarily affect the receptive sphere and that there seems to be a relationship between abnormalities during sleep with a deterioration in verbal comprehension.

Epilepsy, language, and behavior: clinical models in childhood

The complex relationship between epilepsy, language, and behavior is not well understood. Neurologic disorders such as Landau-Kleffner syndrome, electrical status epilepticus during slow-wave sleep, infantile spasms, Lennox-Gastaut syndrome, tuberous sclerosis, autism, and developmental language disorders are useful clinical models in the investigation of this complex relationship. These disorders are reviewed in terms of their contribution to our present knowledge of the relationship between epilepsy, language, and behavior. Present management issues and directions for future research are discussed.

Mental and behavioural deterioration of children with epilepsy and CSWS: acquired epileptic frontal syndrome

Four children with 'epilepsy and continuous spike-wave sleep' syndrome and mental and behavioural regression were followed prospectively with neuropsychological tests, behavioural questionnaires and sleep EEG performed at regular intervals between 1 1/2 and four years of age. The children showed a pattern of behavioural and cognitive disturbances similar to that found in some developmental autistic-like disorders, but also in adult frontal syndrome. Deterioration was probably due to an unusual long-standing epileptic dysfunction involving the frontal lobes. The process is potentially reversible and seems to be the same as postulated for acquired epileptic aphasia, but in a different localization.

Intracranial EEG monitoring in Landau-Kleffner syndrome associated with left temporal lobe astrocytoma

A 3 1/2-year-old boy developed partial complex seizures with right-sided motor activity, occasionally secondarily generalized at age 18 months. Initial EEG showed left-sided focal epileptiform discharges. Seizures became refractory to antiepileptic drugs (AEDs). At age 3 years, there was severe language deterioration consistent with Landau-Kleffner syndrome (LKS). At that time, an EEG showed almost continual generalized spikes and polyspikes, worse during sleep. Video-EEG showed generalized tonic seizures associated with generalized EEG ictal activity. Magnetic resonance imaging (MRI) showed a cystic and solid lesion of the left hippocampal and parahippocampal gyri without surrounding edema. Subdural strip electrodes under the left temporal and overlying the left frontal lobes demonstrated interictal spikes simultaneously in all recording contacts. Ictal EEG activity occurred in the temporal electrodes 0.2-1 s before appearing in the frontal electrodes. After left temporal lobectomy with subtotal resection of a low-grade astrocytoma, he had an immediate marked decrease in seizures. In 1 month he was seizure-free, and in 6 months had no further seizures and markedly improved language. These findings provide further evidence that left temporal structural epileptogenic lesions may contribute significantly to the pathophysiology of LKS.