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

Surgically Remediable Secondary Network Epileptic Encephalopathies With Continuous Spike Wave in Sleep: Lesions May Not Be Visible on Brain Magnetic Resonance Imaging (MRI)

BACKGROUND

Continuous spike wave in sleep (CSWS) is an electroencephalogram (EEG) pattern associated with developmental and epileptic encephalopathy with spike-and-wave activation in sleep (DEE-SWAS). This etiologically heterogeneous syndrome may occur because of genetic factors and congenital or acquired brain lesions. We studied the pattern of clinical presentation and underlying etiologies in patients with DEE-SWAS that respond to resective surgery.

METHODS

We reviewed our clinical and research databases for patients who had resolution of CSWS following surgical resection of a focal lesion.

RESULTS

We identified 5 patients meeting inclusion criteria. In 3 of 5, an epileptogenic structural abnormality was not apparent on brain magnetic resonance imaging (MRI). In all 3 patients, focal cortical dysplasia was identified through intracranial EEG monitoring.

SIGNIFICANCE

DEE-SWAS may be a secondary bilateral network epilepsy syndrome, which can be treated with resection of the inciting focal lesion. In patients with drug-resistant CSWS, clinicians should consider a complete epilepsy presurgical workup, including intracranial EEG monitoring.

Differential diagnosis between autism spectrum disorder and other developmental disorders with emphasis on the preschool period

BACKGROUND

Neurodevelopmental disorders are a heterogeneous group of conditions that manifest as delays or deviations in the acquisition of expected developmental milestones and behavioral changes. Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in communication and social interaction and by repetitive and restricted patterns of behavior, interests and activities. The aim of this review is to discuss the clinical features of the differential diagnoses of ASD that are prevalent among preschoolers, focusing on their similarities and disparities.

DATA SOURCES

The international medical literature search was conducted using PubMed and was revised regarding the subject using single and/or combined keywords as follows: differential diagnosis, preschoolers, diagnostic challenge, attention deficit hyperactivity disorder, intellectual disability, high abilities/giftedness, childhood apraxia of speech, social communication disorder, Landau-Kleffner syndrome, stereotyped movement disorder and excessive screen time.

RESULTS

We describe conditions commonly found in clinical practice, taking ASD as a reference. We addressed converging and divergent aspects of behavior, cognition, communication, language, speech, socialization, and stereotypes for the diagnosis of ASD and other disorders identified as potential differential or comorbid diagnoses.

CONCLUSIONS

The ranking and characterization of symptoms appear to be essential for better understanding the underlying common ground between children with developmental disorders and children with ASD, thus properly diagnosing and directing social, professional, or medication interventions. This detailed discussion adds to the literature since, although ASD differential diagnoses are frequently mentioned and discussed in textbooks and journal articles, they rarely occupy a prominent place as we aimed herein.

Global Synchronization of Multichannel EEG in Patients With Electrical Status Epilepticus in Sleep

In the research field of epilepsy, it is a challenge to understand the transition of brain activity to electrical status epilepticus in sleep (ESES). In this study, an S-estimator method is proposed to describe the course of global synchronization in multichannel electroencephalograph (EEG) from awake to sleep in 11 patients with ESES. The study confirms that there is a significant increase in spikes and global synchronization from awake to sleep. It is also found that global synchronization is strongly correlated with spikes. The proposed method has the potential of revealing the intrinsic features of EEG signals and the underlying brain dynamics in ESES.

Generalized epilepsies: immunologic and inflammatory mechanisms

This article focuses on the inflammatory processes in patients with generalized epilepsies. We specifically review the data regarding West, Lennox-Gastaut, and Landau-Kleffner syndromes as they have generalized clinical or electroencephalogram features. There is substantial evidence for a pathogenic implication of immune mechanisms in these epilepsies. Animal models and abnormalities in both cellular and humoral immunity support this hypothesis. They also appear to be particularly responsive to immunomodulatory therapies, which has raised the speculation that an unbalanced immune system may play an important role in the pathophysiology of these epileptic syndromes. In this article, we discuss clinical and experimental data that support the potential implication of immune mediated inflammation and immune response in the mechanism of these entities.

Landau-Kleffner syndrome: a study of 29 patients

PURPOSE

The aim of the study was to retrospectively analyze the electroclinical features, etiology, treatment, and prognosis of 29 patients with Landau-Kleffner syndrome (LKS) with a long-term follow-up.

METHODS

Inclusion criteria were a diagnosis of LKS with: (1) acquired aphasia or verbal auditory aphasia; (2) with or without focal seizures, secondarily generalized tonic-clonic seizures, absences, or atonic seizures.

RESULTS

Mean follow-up was 12 years. All cases except six had seizures. Before the onset of aphasia, developmental language and behavioral disturbances were present in 19 and 14 patients, respectively. All patients had verbal auditory agnosia. Aphasia was severe in 24 patients and moderate in five. Nonlinguistic cognitive dysfunctions were moderate in 14 patients. Behavioral disturbances were found in 16 patients. During the continuous spike-and-wave discharges during slow sleep phase, the spike-wave index was >85% in 15, 50-85% in eight, and 30-50% in four. In two patients, the EEG recording showed occasional bilateral spikes, without continuous spike-and-wave discharges during slow sleep. In this phase, the awake EEG recording showed more frequent interictal abnormalities, predominantly in the temporal regions. Eight patients recovered language completely, but the remaining patients continue to have language deficits of different degrees.

CONCLUSION

Landau-Kleffner syndrome is an epileptic encephalopathy characterized by acquired verbal auditory aphasia and seizures in most of the patients associated with continuous or almost continuous spike-and-wave discharges during slow wave sleep. The most commonly used treatments were clobazam, ethosuximide, sulthiame. High-dose steroids were also administered. Adequate and early management may avoid language and cognitive deterioration.

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.

A child with refractory complex partial seizures, right temporal ganglioglioma, contralateral continuous electrical status epilepticus, and a secondary Landau-Kleffner autistic syndrome

A 7-year-old, right-handed girl started to have seizures at age 1 year 4 months. She developed normally until age 4 when she had worsening of seizures with auditory verbal agnosia, complete aphasia, and a behavioral disorder fulfilling the diagnostic criteria of autism. Medical therapy failed. MRI revealed a right temporal tumor. Video/EEG monitoring at age 7 showed contralateral electrical status epilepticus in wakefulness and sleep and ipsilateral onset of seizures. Resection (ganglioglioma with excessive inflammation) resulted in seizure freedom and marked reduction of the autistic features. This case is unique for being, to our knowledge, (1) the first in which a lesion located in the right, rather than left, temporal lobe resulted in secondary falsely localizing left temporal lobe electrical status epilepticus with a clinical picture of Landau-Kleffner syndrome and autism, and (2) the fourth reported patient with lesional Landau-Kleffner syndrome to respond to resective surgery.

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

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

Landau–Kleffner syndrome is not an eponymic badge of ignorance

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

Children with ESES: variability in the syndrome

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

The Landau-Kleffner syndrome

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

Landau-Kleffner syndrome: study of four cases

We describe four patients with clinical features of Landau-Kleffner syndrome and discuss electroencephalographic features, treatment and prognosis. Anticonvulsants and prednisone were used for treatment with good control of seizures in all cases and a less effect response in acquired aphasia. Further studies are necessary to elucidate the causes and management of this syndrome.

Efficacy of intravenous immunoglobulin in Landau-Kleffner syndrome

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

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.

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.

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.

Successful use of intravenous immunoglobulin as initial monotherapy in Landau-Kleffner syndrome

PURPOSE

There is a need for new and more effective therapies for Landau-Kleffner syndrome. In this article we present the first case in which a patient with Landau-Kleffner syndrome was given intravenous immunoglobulin (IVIG) as his first and only therapy and responded to it.

METHODS

This previously healthy, left-handed boy presented at 31 months of age with a 3-month history of auditory agnosia, behavioral abnormalities, and progressive, eventually complete loss of speech. Electroencephalography (EEG) showed frequent and, in sleep, continuous right central and temporal spike slow wave discharges. Metabolic workup, magnetic resonance imaging, and auditory evoked potentials were normal. Cerebrospinal fluid IgG index was high (18%). The patient was treated with IVIG, as his initial and only therapy, receiving 500 mg/kg/day over four consecutive days.

RESULTS

On the third day of IVIG, the patient started using single words, and on the fourth, two-word sentences. Two weeks later his speech and behavior returned to normal. At the end of 4 days of IVIG therapy, EEG was within normal limits. Two months later, however, he had a severe relapse clinically and by EEG. He promptly responded to another course of IVIG. A subsequent cerebrospinal fluid IgG index showed normalization (6%). Three months later he had essentially normal speech and behavior.

CONCLUSIONS

Repeated, immediate, and remarkable clinical and EEG responses of this patient suggest that IVIG was helpful as first-line therapy in the treatment of Landau-Kleffner syndrome. It also supports the hypothesis that immunological mechanisms contributed to his symptoms.

Acquired aphasia in acute disseminated encephalomyelitis

A 12-year-old boy developed a convulsion, hemiparesis, and acquired aphasia with paroxysmal electroencephalogram (EEG) abnormalities consisting of repetitive spikes and waves in the left centro-parietal region. T2-weighted magnetic resonance imaging disclosed high intensity lesions in the left pre-Sylvian and right frontal areas. He was diagnosed as having acute disseminated encephalomyelitis, and thus the oral administration of phenytoin and steroid pulse therapy were begun. With these treatments, his hemiparesis disappeared and the aphasia also improved gradually. Magnetic resonance imaging examination revealed the disappearance of the previously noted abnormalities, and the EEG abnormalities disappeared as well. This patient is a rare case of acute disseminated encephalomyelitis presenting an acquired aphasia. A focal lesion of acute disseminated encephalomyelitis may be responsible for the acquired aphasia. The distinction from Landau-Kleffner syndrome is also discussed.

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.

Conduction aphasia in a 3-year-old with a left posterior cortical/subcortical abscess

A 3-year-old, right-handed girl developed a conduction-type aphasia following a second generalized seizure in the setting of a developing abscess involving left subcortical and cortical angular gyrus and arcuate fasciculus, and the posterior corpus callosum. The language disorder was fluent, characterized by age appropriate mean length of utterance and syntax, but with markedly reduced spontaneity of output, rapid rate of speech and mild dysarthria. Comprehension was relatively, but not completely spared. Naming, repetition, and reading (letters) were initially markedly impaired. Improvements in naming and repetition were associated with both literal and semantic paraphasias. Writing skills in the form of drawing were spared, but a mild apraxia to verbal command and imitation was initially present. Despite her young age, this child's fluent conduction aphasia and lesion localization were adult-like. Multimodal memory difficulties appeared to underlie what is best described as conduction aphasia.

Successful use of intravenous immunoglobulins in Landau-Kleffner syndrome

A detailed history of a boy with Landau-Kleffner syndrome is presented, demonstrating a close relationship between language functioning and paroxysmal electroencephalogram activity. During a 3-year 6-month follow-up period, three abrupt deteriorations of all language functions occurred: the child became totally noninteractive with his environment within 1 week's time. Two of these deteriorations were reversed with steroid treatment, with an identical recovery phase. Intravenous immunoglobulins had a very dramatic and comparable effect in the third relapse; both language functions and electroencephalogram abnormalities were influenced significantly by the intravenous immunoglobulin treatment.

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.

Acquired epileptiform aphasia

The acquired epileptiform aphasias, with Landau-Kleffner's syndrome as the example, represent an important group of syndromes in our quest to understand the relationship between epilepsy, language, and behavior. The controversy that truly frames the literature on the acquired epileptiform aphasias is the role of epileptiform activity on language, behavior, and cognition. This review expands the model of Landau-Kleffner's syndrome to include two other encephalopathies with language and behavioral regression in association with an epileptiform electroencephalogram. Both of these encephalopathies, autistic epileptiform regression and disintegrative epileptiform regression, are associated with an acquired language disorder. The developmental period in which the acquired language disorder begins, the type of language disorder, and the location and type of the epileptiform activity are all important variables that may affect clinical manifestations and prognosis.

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.

Landau-Kleffner syndrome: consistent response to repeated intravenous gamma-globulin doses: a case report

PURPOSE

Although several treatments have been tried for Landau-Kleffner syndrome (LKS) too many patients are refractory to known therapies. We report an 8-year-old girl who failed other therapies but who had a consistent response after treatment with intravenous (i.v.) gamma-globulin.

METHODS

We monitored the girl from the age of 6 years, when she presented with a 6-month history of loss of language with normal hearing, normal brain magnetic resonance imaging (MRI), increased cerebrospinal fluid (CSF) IgG index, and an EEG showing almost continuous, predominantly left-sided spike- and slow-wave complexes. She had no clinical seizures and did not respond to consecutive trials of valproate (VPA), clonazepam (CZP), prednisone, and carbamazepine (CBZ). She received three courses of intravenous (i.v.) gamma-globulin; after each course, clinical and electrographic improvement lasted a few months. After each of the initial two courses, clinical improvement lasted 3-4 months but was followed by recurrence of the spikes on the EEG and by speech deterioration.

RESULTS

However, her last remission has been continuous for the past 16 months. Her CSF IgG index became normal after the first i.v. gamma-globulin infusion.

CONCLUSIONS

Based on our experience with this patient and on other investigators' experience, we believe that further research into immunologic mechanisms and therapies of this syndrome are warranted.

24-year preoperative evolution of a temporal astrocytoma

We report the case of a patient suffering since 5 months of age from complex focal seizures that could not be controlled with medication and who developed severe psychomotor retardation. When she was 25 years old she was operated on for a left temporal lobe type II astrocytoma which had been detected but misinterpreted on CT scans performed at 12 and 18 years of age. After surgical and radiotherapy treatment the patient was seizure-free for 9 months, but then epilepsy reappeared and the patient died 19 months after surgery. Postsurgical malignant transformation is suspected but not histologically confirmed.

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.

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.

The Landau-Kleffner Syndrome: a review

The Landau-Kleffner syndrome or the syndrome of acquired epileptic aphasia was first described in 1957. The disorder is characterised by gradual or rapid loss of language in a previously normal child. All children have abnormal EEG compatible with the diagnosis of epilepsy, however, only 70% have clinical seizures. The present article presents a review of the current knowledge concerning this disorder. Information is provided related to the clinical picture, etiology, pathogenesis, treatment and outcome.

[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.