Landau-Kleffner syndrome. Treatment with subpial intracortical transection

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.

Recognition of the various expressions of anxiety, psychosis, and aggression in epilepsy

Anxiety, psychosis, and aggressive behavior are among the frequent comorbid psychiatric disorders identified in patients with epilepsy. Often the clinical manifestations of these disorders vary according to their temporal relation relative to seizure occurrence. Thus, postictal symptoms of anxiety or psychosis differ in severity, duration, and response to treatment with interictal symptomatology. Psychiatric symptomatology in epilepsy can appear concurrently with the seizure disorder and improve or remit on the abolition of epileptic activity. We refer to these as paraictal psychiatric phenomena. Such is the case of aggressive disturbances associated with gelastic seizures caused by hypothalamic hamartomas. In this article, three case studies are presented to illustrate the importance of distinguishing psychiatric symptoms of anxiety, psychosis, and aggression, with respect to their temporal relation with seizure occurrence.

Benigne epilepsietypische Potentiale des Kindesalters (Rolando-Spikes) - neurobiologische und neuropsychologische Befunde und ihre klinische Bedeutung in der Kinder- und Jugendpsychiatrie

Zusammenfassung: Einleitung: Die Rolando-Epilepsie ist das häufigste Epilepsie-Syndrom im Kindesalter. Sie ist elektroenzephalographisch charakterisiert durch das Auftreten von fokalen epilepsietypischen Potentialen, den sog. Rolando-Spikes (benigne epilepsietypische Potentiale des Kindesalters, BEPK). BEPK treten mit einer Häufigkeit von etwa 1,5 bis 2,4% bei Kindern auf; nur ein Zehntel erleidet epileptische Anfälle. Methoden: Diese Arbeit gibt einen Überblick über genetische, epidemiologische, radiologische, neurophysiologische, metabolische und neuropsychologische Befunde bei Kindern mit BEPK. Resultate: Der epileptologische Verlauf ist günstig, eventuell auftretende Anfälle sistieren spätestens mit der Pubertät; die epilepsietypischen Potentiale sind dann nicht mehr nachweisbar. Entgegen früherer Annahmen erstreckt sich das Symptomenspektrum über seltene Anfälle hinaus auf neuropsychologische Beeinträchtigungen und Verhaltensauffälligkeiten, auch bei Kindern ohne manifeste Anfälle. Der Einfluss der Rolando-Spikes auf die Entwicklung betroffener Kinder und ihr Verhalten ist unklar. Durch zwei Modelle wird versucht, den Zusammenhang von paroxysmaler EEG-Aktivität und neuropsychologischen Auffälligkeiten zu erklären. Das erste betrachtet die beobachtbaren Defizite als vorübergehende kognitive Beeinträchtigung infolge der epileptischen Aktivität; das zweite sieht als Ursache eine genetisch bedingte zerebrale Reifungsstörung mit enger Verwandtschaft zu Teilleistungsstörungen. Schlussfolgerung: Die Behandlungsnotwendigkeit neuropsychiatrischer Symptome bei Kindern mit BEPK ohne manifeste Anfälle wird derzeit kontrovers diskutiert.

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.

Epileptic encephalopathies and their relationship to developmental disorders: Do spikes cause autism?

Epileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10-15% of children with pervasive developmental disorders (PDD) and 8-10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2-3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures ("autism with epileptic regression") and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal discharges per se cause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDD without seizures; that is, there is no evidence that treatment to eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism.

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.

Cognitive impairment during epileptiform discharges: is it ever justifiable to treat the EEG?

Epileptiform EEG discharges are not confined to people with epilepsy, and their frequency is only weakly related to severity. A fundamental principle of EEG practice is, therefore, to avoid overinterpretation of epileptiform activity. Epileptiform discharges not accompanied by obvious clinical events are generally regarded as subclinical or interictal. However, in many patients sensitive methods of observation, notably continuous psychological testing, show brief episodes of impaired cognitive function during such discharges. This phenomenon of transitory cognitive impairment (TCI) is found in about 50% of patients who show discharges during testing. TCI is not simple inattention. The effects are material and site specific: lateralised discharges are associated with deficits of functions mediated by the hemisphere in which the discharges occur. Conversely, specific tasks can activate or suppress focal discharges over the brain regions that mediate the cognitive activity in question. TCI clearly contributes to the cognitive problems of some people with epilepsy and may cause deficits that pass unrecognised. TCI is demonstrable in many cases of benign partial epilepsy of childhood, a disorder once thought to have no adverse psychological effects. TCI can contribute to abnormalities of psychological test profiles and interferes with daily tasks, such as reading and driving. In children it may be associated with behavioural disorders. An important practical issue is whether TCI materially impairs psychosocial function and, if so, whether drug treatment is desirable or effective. Uncontrolled reports and two preliminary randomised controlled trials of antiepileptic treatment of TCI have suggested that suppression of discharges is associated with significant improvement in psychosocial function.

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.

Landau-Kleffner syndrome responsive to levetiracetam

A 5-year-old girl with Landau-Kleffner syndrome is discussed. The child began having seizures at age 4 associated with language deterioration despite anticonvulsant therapy. With levetiracetam monotherapy to a dose of 60 mg/kg/day and discontinuation of carbamazepine and valproic acid, her language has improved and seizures are controlled. Levetiracetam should be considered as therapy for Landau-Kleffner syndrome.

Surgical treatment of multifocal epilepsy involving eloquent cortex

PURPOSE

This report describes our long-term follow-up for combined resective surgery and multiple subpial transections (MSTs) in patients with refractory epilepsy involving eloquent and noneloquent cortex in multiple lobes. Multiple independent seizure foci made these patients poor candidates for conventional surgery.

METHODS

MST and resective surgery were used in 13 patients to treat localization-related refractory epilepsy involving eloquent and noneloquent cortex of two or more lobes. Preoperative investigation was followed by invasive monitoring.

RESULTS

Eleven patients had MST plus resection involving two different lobes, and two patients had MST plus resection involving three different lobes. MSTs were performed on the primary sensorimotor cortex (eight patients), temporal language area (two patients), Broca's area (one patient), and on both frontal motor and temporal language areas (two patients). Nine patients had a two-stage procedure, and four patients had a three-stage procedure (two consecutive subdural grid studies followed by resections). Average follow-up was 59.2 months (range, 42-98 months). With a modified Engel Outcome Scale, four patients (31%) had a class I outcome; three (23%), class II; three (23%), class III; and three (23%), class IV. Ten (77%) patients had a >50% reduction of seizure burden.

CONCLUSIONS

Combined MST and resection can meaningfully improve seizure control in patients with multifocal epilepsy involving eloquent cortex. Prospective randomized studies are needed.

Treatment considerations: role of surgery

Patients with developmental disabilities, including retardation and global developmental delay, are not ideal candidates for epilepsy surgery. Because they have an increased likelihood of diffuse brain dysfunction and multifocal or generalized epileptogenic zones, there is an increased chance that a focal cortical resection will not confer a major improvement in their seizure frequency and severity. There is also increased concern that cortical resection will lead to increase in the patient's disability. However, by applying the basic principles of epilepsy surgery selection (i.e., convergence of multiple lines of localizing evidence) to this population, patients with a reasonable likelihood of good seizure control can be identified. Various means of localizing seizure onset are reviewed, including history and examination, electroencephalography, magnetic resonance imaging, position emission tomography, single-photon-emission tomography, and magnetoencephalography.

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.

Treatment strategies in Landau-Kleffner syndrome and paraictal psychiatric and cognitive disturbances

Psychiatric and cognitive disturbances of the peri-ictal period (i.e., the seizure prodrome and the postictal period) can be considered paraictal disturbances, as they are directly related to the ictal event. There are also certain interictal psychiatric and cognitive disturbances that become apparent concomitantly with the onset of a seizure disorder and remit and/or significantly improve upon its remission. Such disorders also fall under the classification paraictal disorders, and are exemplified by Landau-Kleffner syndrome (LKS), a disorder in which language and psychiatric disturbances begin with the onset of epileptic activity and improve upon its disappearance. In this article, we review the treatment of paraictal cognitive and psychiatric disorders presenting as preictal and postictal psychiatric disturbances and LKS.

Epilepsy in autism

There is an increased but variable risk of epilepsy in autism. Three main factors--age, cognitive level, and type of language disorder--account for variability in the reported prevalence of epilepsy. The prevalence is highest in studies that have included adolescents and young adults, individuals with moderate to severe mental retardation and those with motor deficits, and individuals with severe receptive language deficits. The association of autism with clinical or subclinical epilepsy might denote common genetic factors in some cases. Whether subclinical epilepsy has adverse effects on cognition, language, and behaviour is debated, as is the relation of autistic regression with an epileptiform electroencephalogram to Landau-Kleffner syndrome. There is no evidence-based treatment recommendation for individuals with autism, regression, and subclinical epilepsy. Double-blind studies with sufficient power to resolve this issue are urgently needed.

Language dysfunction in epileptic conditions

Epilepsy may disrupt brain functions necessary for language development by its associated intellectual disabilities or directly as a consequence of the seizure disorder. Additionally, in recent years, there has been increasing recognition of the association of epileptiform electroencephalogram (EEG) abnormalities with language disorders and autism spectrum disorders. Any process that impairs language function has long-term consequences for academic, social, and occupational adjustments in children and adolescents with epilepsy. Furthermore, impairments in specific language abilities can impact memory and learning abilities. This article reviews interictal language function in children and adults with epilepsy; epilepsy surgery and language outcome; and language disorders associated with abnormal EEGs. The relationship between epilepsy and language function is complicated as the neuroanatomic circuits common to both overlap. We demonstrate how magnetoencephalography (MEG) offers the ability to analyze the relationship of language, EEG abnormalities, and epilepsy.

Do occasional brief seizures cause detectable clinical consequences?

Seizures, particularly when prolonged or frequent, have been associated with a variety of adverse outcomes. However, epidemiological data provide little evidence for adverse effects of isolated brief seizures per se. Even the animal data is mostly for prolonged or frequent seizures. Febrile seizures lasting < 10 min have not been associated with adverse seizures or cognitive outcomes. Treating either febrile seizures or other acute symptomatic seizures does not reduce the risk of subsequent epilepsy. In subjects with a first unprovoked seizure, seizure duration does not influence recurrence risk. Furthermore, treatment after a first unprovoked seizure reduces recurrence risk, but does not alter long-term prognosis. In epidemiological studies of newly diagnosed epilepsy, the number of seizures prior to therapy does not influence prognosis. There are a variety of specific epilepsy syndromes associated with poor cognitive outcomes and with progressive loss of function. However, the poor outcomes in these syndromes do not appear to be the result of seizures per se but rather to the specific syndrome and to the frequent interictal spike activity seen in these patients. Antiepileptic drugs, while effective in reducing seizure recurrence are also associated with a variety of potential adverse effects. On a risk-benefit basis, the available epidemiologic data do not justify starting treatment after the first seizure to attempt to influence long-term prognosis.

So what can we conclude--do seizures damage the brain?

Evidence is presented, in this volume, for and against the thesis that single, self-limited seizures can damage the brain. Consideration must be given to the fact that there are many different types of seizures, which undoubtedly induce a variety of postictal consequences. Whether any of these consequences constitute brain damage depends upon the definition of damage, which could range from enduring functional changes of single neurons or circuits, to actual cell death. Although many seizure-induced mechanisms have been postulated, or even demonstrated, that can give rise to persistent neuronal disturbances, including neuronal death, they are only of clinical concern if they result in interictal neurological or cognitive dysfunction, developmental delay, or progressive epileptogenesis that makes seizures worse. Although animal studies indicate it is very likely that some seizures, under some circumstances, do, in fact, damage the brain in a clinically meaningful manner, the principal contribution of this volume is to identify areas of future basic and clinical research designed to identify those seizures which present a risk of causing enduring neuronal disruption, the circumstances under which these changes are likely to occur, their nature and effects on behavior, and, ultimately, rational approaches to prevention.

Multiple subpial transections: outcome and complications in 20 patients who did not undergo resection

OBJECT

The authors describe patient characteristics, surgical methods, complications, and outcome over time in a cohort of patients who underwent multiple subpial transection (MST) without concomitant cortical resection.

METHODS

Twenty consecutive patients in whom drug-resistant epilepsy had been diagnosed a mean of 16 +/- 9 years earlier (mean +/- standard deviation [SD]) were treated with MST without cortical resection. The mean follow-up period was 49.3 +/- 18.3 months (mean +/- SD, median 58 months). At 12 months of follow up, two of the 20 patients were Engel Class I, one was Class II, six were Class III, and 11 were Class IV. At latest follow up, one patient was Engel Class I, one was Class II, seven were Class III, and 11 were Class IV. According to an alternative five-tiered classification system, two outcomes were excellent, seven were good, one was fair, nine were poor, and one was worse. Outcome was found to be better in patients with no lesions observed on magnetic resonance (MR) imaging, and worse in those with large MST areas. Outcome had a tendency to change (this occurred in 13 of 20 cases). Five patients (25%) improved and seven (35%) deteriorated in Engel outcome class, and in one (5%) both developments occurred over time. Most outcome class changes occurred before the end of the 2nd year (nine), and four were observed in the 5th year. There where seven transient neurological deficits and four surgical complications. There was no permanent significant morbidity, and there were no deaths.

CONCLUSIONS

Forty-five percent of patients achieved a worthwhile improvement after pure MST, if Engel outcome Class III is deemed a worthwhile improvement. The alternative five-tiered classification resulted in 50% with worthwhile improvement (excellent, good, or fair outcome), 45% with poor, and 5% with worse outcome. Lesions that are detectable on MR imaging, and large MST areas are predictive of worse results. Significant intraoperative problems may arise, but this happens infrequently. There is a notable rate of transient morbidity but the rate of permanent morbidity is not significant.

Intravenous immunoglobulin in neurological disease: a specialist review

Treatment of neurological disorders with intravenous immunoglobulin (IVIg) is an increasing feature of our practice for an expanding range of indications. For some there is evidence of benefit from randomised controlled trials, whereas for others evidence is anecdotal. The relative rarity of some of the disorders means that good randomised control trials will be difficult to deliver. Meanwhile, the treatment is costly and pressure to "do something" in often distressing disorders considerable. This review follows a 1 day meeting of the authors in November 2000 and examines current evidence for the use of IVIg in neurological conditions and comments on mechanisms of action, delivery, safety and tolerability, and health economic issues. Evidence of efficacy has been classified into levels for healthcare interventions (tables 1 and 2).

Multiple subpial transection for intractable partial epilepsy: an international meta-analysis

PURPOSE

Because the number and variety of patients at any single facility is not sufficient for clinical or statistical analysis, data from six major epilepsy centers that performed multiple subpial transections (MSTs) for medically intractable epilepsy were collected.

METHODS

A meta-analysis was performed to elucidate the indications and outcome, and to assess the results of the procedure. Overall, 211 patients were represented with data regarding preoperative evaluation, procedures, seizure types and frequencies before and after surgery, postoperative deficits, and demographic information. Fifty-three patients underwent MST without resection.

RESULTS

In patients with MST plus resection, excellent outcome (>95% reduction in seizure frequency) was obtained in 87% of patients for generalized seizures, 68% for complex partial seizures, and 68% for simple partial seizures. For the patients who underwent MST without resection, the rate of excellent outcome was only slightly lower, at 71% for generalized, 62% for complex partial, and 63% for simple partial seizures. EEG localization, age at epilepsy onset, duration of epilepsy, and location of MST were not significant predictors of outcome for any kinds of seizures after MST, with or without resection. New neurologic deficits were found in 47 patients overall, comparable in MST with resection (23%) or without (19%).

CONCLUSIONS

These preliminary results suggest that MST has efficacy by itself, with minimal neurologic compromise, in cases in which resective surgery cannot be used to treat uncontrolled epilepsy. MST should be investigated as a stand-alone procedure to allow further development of criteria and predictive factors for outcome.

Diagnosis and treatment of nonconvulsive status epilepticus

Nonconvulsive status epilepticus (SE) is not uncommon and comprises at least one-third of all cases of SE. However, nonconvulsive SE consists of very different syndromes, a common feature being the difficulty in making the diagnosis. In this review, nonconvulsive SE is divided into typical absence SE, complex partial SE, nonconvulsive SE in patients with learning difficulties (including electrical SE during sleep, atypical absence SE and tonic SE), and nonconvulsive SE in coma. These conditions have different prognoses and treatments. The diagnosis of these conditions is critically dependent on EEG. When the EEG demonstrates typical ictal patterns, the diagnosis is usually straightforward. However, in many circumstances the EEG has to be differentiated from encephalopathic patterns, and this differentiation can prove troublesome, although the clinical and electrographic response to treatment can prove helpful. Nonconvulsive SE in patients with learning difficulties possibly provides the greatest diagnostic difficulty; the clinical presentation can be subtle resulting in the diagnosis being frequently missed. Whether the neuronal damage that occurs in convulsive SE and in animal models of limbic SE also occurs in nonconvulsive SE in humans is still a matter of debate. There are critical differences between the animal models and the human condition. Indeed, the prognosis of nonconvulsive SE is usually dependent on the underlying aetiology rather than the persistence of electrographic discharges. Because of these doubts, a more conservative approach to the treatment of particular types of nonconvulsive SE (those with a better prognosis) has been taken in this article. Thus, in most instances, oral benzodiazepines for the treatment of typical absence SE and complex partial SE are recommended. In some circumstances intravenous medication is necessary, but in neither condition is anaesthetic coma recommended. This contrasts with nonconvulsive SE in coma in which a more aggressive approach is suggested. Until there are more relevant animal models, and controlled trials of conservative versus more aggressive treatment, treatment regimens for nonconvulsive SE will remain largely speculative.

Childhood epilepsy in relation to mental handicap and behavioural disorders

Epidemiological studies indicate that there is a high rate of mental retardation and behavioural problems in children with epilepsy. In some cases both the epilepsy and the mental retardation will have a common cause, such as a metabolic disorder or brain trauma. However, in other children, the epilepsy itself may cause either temporary or permanent learning problems. When permanent learning disability can be prevented it is important to treat the epilepsy early and effectively. Children with specific learning difficulties and memory problems can benefit greatly from appropriate management. There are many causes of behavioural disturbance in children with epilepsy. These causes include the epilepsy itself, treatment of the epilepsy, reactions to the epilepsy, associated brain damage/dysfunction and causes that are equally applicable to children who do not have epilepsy. Identifying the cause or causes in each child allows rational management to be provided. Antiepileptic treatment with medication or surgery can either improve the situation or make matters worse. The treatment should be tailored to the needs of the individual child. If surgery is required, there is a strong argument for performing this early in life, both to allow the greatest opportunity for brain plasticity and also to allow the child full benefit from the important developmental and educational years, without the problems that can be associated with the epilepsy. Skilled management of children with epilepsy who have mental retardation and/or behavioural problems can be very rewarding both for the family and for the professionals involved.

The Landau-Kleffner Syndrome

Landau-Kleffner syndrome (LKS), or acquired epileptiform aphasia, is an epilepsy syndrome involving progressive neuropsychological impairment related to the appearance of paroxysmal electroencephalograph (EEG) activity. LKS appears to share a common pathophysiologic mechanism with continuous spike-wave of sleep (CSWS), acquired epileptic opercular syndrome (AEOS), and even benign childhood epilepsy with centrotemporal spikes (BECTS), with differentiating factors including age of onset, area of primary epileptogenicity, and severity of clinical presentation. This article covers the clinical, diagnostic, therapeutic, and prognostic features of LKS. In a child with autistic spectrum disorder, the presence of a fluctuating clinical course or regression should raise suspicion for the presence of associated epilepsy.

Acquired epileptiform opercular syndrome: a case report and results of single photon emission computed tomography and computer-assisted electroencephalographic analysis

We report here a girl aged 5 years 3 months with cryptogenic localization-related epilepsy who showed a prolonged episode characterized by dysarthria, dysphagia, drooling and paresis of the right arm associated with almost continuous diffuse sharp-slow wave complexes during sleep. These symptoms were not directly related to seizures or to each sharp-slow wave complex revealed by examination during the video electroencephalographic (EEG) recording. The interictal single photon emission compute tomography showed a localized high perfusion area in the left posterior frontal region. The introduction of clonazepam completely controlled the clinical symptoms as well as the EEG abnormality within 2 weeks. After 4 months of remission, a similar episode recurred which was associated with aggravation of EEG. The clinical and EEG characteristics of this patient were identical to those of acquired epileptiform opercular syndrome (AEOS), a newly proposed epileptic syndrome, in which a transient operculum syndrome develops in association with continuous spike-and-wave activity during slow sleep (CSWS). Computer-assisted EEG analysis demonstrated that the epileptic EEG focus was located in the left sylvian fissure, and produced secondary bilateral synchronous sharp-slow complexes. The present study further supports the hypothesis that the electrical interference by CSWS creates bilateral opercular dysfunction through the mechanism of secondary bilateral synchrony, thus producing AEOS.

Surgical treatment of medically refractory epilepsy in childhood

Twenty-five percent of children with epilepsy continue to seize despite the best medical management and may be defined as medically refractory. Many children with medically refractory localization-related epilepsy, i.e. seizures which originate in a particular area of the brain and secondarily spread to involve other brain regions, may benefit from a variety of surgical treatments including hemispherectomy, corpus callosotomy, focal cortical resection of the temporal lobe, focal cortical resection of extratemporal regions of the brain, and multiple subpial resections. A successful outcome from epilepsy surgery is generally defined as a seizure-free state with no imposition of neurologic deficit. In order to achieve these twin goals two criteria must be fulfilled. First, precise localization of the epileptogenic zone in the brain is necessary. The epileptogenic zone may be defined as the region of epileptogenic cerebral cortex whose removal will result in a seizure-free state. Second, one must determine the anatomic localization of eloquent cortex in the brain in order to spare these areas during any planned cortical excision of epileptogenic cortex. Several diagnostic measures may be used to achieve a successful surgical outcome. A clinical history to ascertain the earliest symptom in the clinical progression of the seizure (semiology) is imperative as is ictal and interictal scalp EEG, neuropsychological testing, magnetic resonance imaging, positron emission tomography, single photon emission computerized tomography, and interictal magnetoencephalography. In the typical child undergoing evaluation for epilepsy surgery, if the clinical, neuropsychological, EEG, and radiological data are all concordant and point to the same area of epileptogenicity in the brain, cortical excision of the suspected epileptogenic zone is undertaken. However, if the data are discordant, and/or the epileptogenic zone resides wholly or in part within eloquent cortex, invasive intracranial monitoring from depth and/or subdural electrodes during a seizure is required to map out the areas of epileptogenicity in the brain. The assessment of potential risks and benefits for this type of epilepsy surgery in children involves complex age-related issues, including the possible impact of uncontrolled seizures, medication, or surgery on learning and development.

Treatment of Childhood Idiopathic Language Deterioration with Valproate

Childhood idiopathic language deterioration is a rare condition in which children lose previously gained language skills. In some children this language deterioration occurs in association with behavioral seizures or EEG epileptiform activity. The effectiveness of antiepileptic drugs in this patient population is not known. Here we retrospectively reviewed records of 57 children with childhood idiopathic language deterioration associated with seizures or epileptiform activity on their EEG who received valproate for the purpose of treating their language impairment. In 22 of the children improvement in language skills was observed. In two children language returned to normal while in the other 20 the improvement was modest. Children who responded to valproate had an earlier age of onset of the aphasia than children who were nonresponders. Seizure type, EEG findings, developmental status, and presence or absence of a frequency-modulated auditory evoked potential were not related to response. This study demonstrates that valproate can be helpful in improving language function in some children with idiopathic language deterioration associated with seizures or epileptiform activity on the EEG.

Landau-Kleffner Syndrome: Localization of Epileptogenic Lesion Using Wavelet- Cross-Correlation Analysis

Magnetoencephalographic findings in a 6-year-old patient suffering from acquired aphasia with convulsive disorder (Landau-Kleffner Syndrome, LKS) are presented. The data were analyzed using wavelet-cross-correlation analysis, a nonstationary analysis method developed to analyze the localization of an epileptogenic lesion and the propagation of epileptiform discharges. The results indicate that LKS might be a disorder of the primary temporal cortex, and that the auditory neural network may function as the circuit for the epileptic discharge propagation.

Magnetoencephalography and magnetic source imaging in children

Magnetoencephalography is a technique that detects the magnetic fields associated with the intracellular current flow within neurons, unlike electroencephalography, which measures extracellular volume currents. Superconducting quantum interference devices are used to amplify these very small magnetic field signals. Magnetic source imaging is the combination of functional data derived from magnetoencephalographic recordings coregistered with structural magnetic resonance imaging (MRI). The utility of magnetic source imaging lies in the combination of the submillisecond temporal resolution of magnetoencephalography with the precise anatomic images provided by magnetic resonance imaging. As such, magnetic source imaging is a useful tool for noninvasive localization of the epileptogenic zone in children who are candidates for epilepsy surgery. Similarly, using magnetoencephalographic recordings with evoked and event-related potentials, magnetic source imaging holds great promise as a noninvasive method for precise localization of somatosensory, motor, language, visual, and auditory cortex. Finally, magnetic source imaging is proving a valuable research tool in the investigation of epilepsy, head trauma, brain plasticity, and disorders of language, memory, cognition, and executive function in children.

Language regression in childhood

Language regression is observed both in autistic regression and as part of acquired epileptic aphasia (Landau-Kleffner Syndrome). We prospectively identified 177 children with language regression at four major medical centers, and their clinical characteristics were recorded. Their mean age at regression was 22.8 months. The mean time-to-specialist referral was 38 months of age. Most children (88%) met criteria for autism or manifested autistic features. Males (P = 0.02) and children less than 3 years of age who regressed (P = 0.016) had a higher probability of developing autistic behaviors. Seizures were more common in children who regressed after they reached 3 years of age (P < 0.001), and children with seizures were less likely to have associated autistic regression (P < 0.001). Electroencephalogram abnormalities were reported in 37% of patients and were more common in children with seizures (P < 0.001). At last follow-up, language function was impaired in 88% of the children, although some improvement was noted in 57%. We conclude that the loss of previously acquired language at any age, even if that language only includes a few words or communicative gestures, is often associated with a more global regression in cognition and/or behavior and has serious implications for future function. Early identification and referral of these children is necessary to allow for diagnosis and intervention.

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.

Cognitive and behavioral problems in children with centrotemporal spikes

Atypical features in benign epilepsy of childhood with centrotemporal spikes (BECTS) are not uncommon. There are children with BECTS who do not have a benign outcome in terms of neuropsychologic functioning. BECTS have been linked with Landau-Kleffner syndrome (LKS) and continuous spikes and waves during slow sleep (CSWS). At the Medical College of Georgia from January 1988 to June 1999, 78 children, ages 2-16 years, were identified to have electroencephalogram evidence of centrotemporal spikes. Their medical records were reviewed for developmental history, behavioral problems, and school performance. Children with structural lesions/other epileptic syndromes were excluded. Fifty-six demonstrated a history of clinical seizures compatible with BECTS and 22 demonstrated centrotemporal spikes without clinical seizures. Among all children with centrotemporal spikes, 9% (n = 7) were diagnosed with mild intellectual disability (intelligence quotient < 70), 10% (n = 8) with borderline functioning, 31% (n = 24) with behavioral problems, and 17% (n = 13) with specific learning disabilities. Three children with BECTS experienced language delay and regression. Seizure control for BECTS usually is achieved without much difficulty, with excellent long-term prognosis. However, the data presented indicate that a large number of BECTS patients exhibit learning or behavior problems that require intervention. A small number may demonstrate language outcome similar to children with LKS and CSWS.

Functional neuroimaging of autistic disorders

Functional neuroimaging methods hold promise for elucidating the neurobiology of autistic disorders, yet they present difficult practical and scientific challenges when applied to these complex and heterogeneous syndromes. Single-state studies of brain metabolism and blood flow thus far have failed to yield consistent findings, but suggest considerable variability in regional patterns of cerebral synaptic activity. Patients with idiopathic autism are less likely to show abnormalities than are patients with comorbid illness or epilepsy. Activation studies have begun to suggest alterations in brain organization for language and cognition. Neurotransmitter studies using positron emission tomography (PET) suggest abnormalities of serotonergic and dopaminergic function. Studies using magnetic resonance spectroscopy (MRS) have begun to document metabolic deficits in the frontal cortex and cerebellum. A single study using magnetoencephalography suggests a high incidence of epileptiform activity in children with autistic regression. Research needs include well-controlled developmental studies, particularly of young subjects and relatively homogeneous subgroups, which balance scientific rigor with ethical constraints. Investigations of the serotonergic and dopaminergic systems, limbic-based memory and emotional systems, and the role of epileptiform activity in autism represent priorities for future research.

Treatment of seizure disorders and EEG abnormalities in children with autism spectrum disorders

The treatment of seizure disorders EEG epileptiform abnormalities without epilepsy in children with autism spectrum disorders (ASD) is considered within the context of the relationship of epilepsy and epileptiform disorders to language, behavior, and cognition. There is an increased prevalence of both epilepsy and abnormal potentially epileptogenic activity in children with ASD. Anecdotal evidence suggests that the use of anticonvulsants to treat epileptiform discharges thought to be producing dysfunction in selected aspects of cognition, language, or behavior makes a positive difference in a subgroup of children with ASD, but there is inadequate evidence on which to base specific recommendations. There is, at present, no scientific justification for considering epilepsy surgery in children with ASD in the absence of intractable clinical seizures.

Encephalopathy with electrical status epilepticus during slow sleep or ESES syndrome including the acquired aphasia

Encephalopathy with electrical status epilepticus during sleep or ESES is an age-dependent and self-limited syndrome whose distinctive features include a characteristic age of onset (with a peak around 4-5 years), heterogeneous seizures types (mostly partial motor or unilateral seizures during sleep and absences or falls while awake), a typical EEG pattern (with continuous and diffuse paroxysms occupying at least 85% of slow wave sleep) and a variable neuropsychological regression consisting of IQ decrease, reduction of language (as in acquired aphasia or Landau-Kleffner syndrome), disturbance of behaviour (psychotic states) and motor impairment (in the form of ataxia, dyspraxia, dystonia or unilateral deficit). Despite the long-term favourable outcome of epilepsy and status epilepticus during sleep (SES), the prognosis is guarded because of the persistence of severe neuropsychological and/or motor deficits in approximately half of the patients. No specific treatment has been advocated for this syndrome, but valproate sodium, benzodiazepines and ACTH have been shown to control the seizures and the SES pattern in many cases, although often only temporarily. Subpial transection is proposed in some instances as in non-regressive acquired aphasia. Recent data support the concept that ESES syndrome may include a large subset of developmental or acquired regressive conditions of infancy.