EEG features and epilepsy in patients with autism

Excess of high frequency electroencephalogram oscillations in boys with autism

BACKGROUND

An elevated excitation/inhibition ratio has been suggested as one mechanism underpinning autism. An imbalance between cortical excitation and inhibition may manifest itself in electroencephalogram (EEG) abnormalities in the high frequency range. The aim of this study was to investigate whether beta and gamma range EEG abnormalities are characteristic for young boys with autism (BWA).

METHODS

EEG was recorded during sustained visual attention in two independent samples of BWA from Moscow and Gothenburg, aged 3 to 8 years, and in age matched typically developing boys (TDB). High frequency EEG spectral power was analyzed.

RESULTS

In both samples, BWA demonstrated a pathological increase of gamma (24.4-44.0 Hz) activity at the electrode locations distant from the sources of myogenic artefacts. In both samples, the amount of gamma activity correlated positively with degree of developmental delay in BWA.

CONCLUSIONS

The excess of high frequency oscillations may reflect imbalance in the excitation-inhibition homeostasis in the cortex. Given the important role of high frequency EEG rhythms for perceptual and cognitive processes, early and probably genetically determined abnormalities in the neuronal mechanisms generating high frequency EEG rhythms may contribute to development of the disorder. Further studies are needed to investigate the specificity of the findings for autism.

Autism and vitamin D

Any theory of autism's etiology must take into account its strong genetic basis while explaining its striking epidemiology. The apparent increase in the prevalence of autism over the last 20 years corresponds with increasing medical advice to avoid the sun, advice that has probably lowered vitamin D levels and would theoretically greatly lower activated vitamin D (calcitriol) levels in developing brains. Animal data has repeatedly shown that severe vitamin D deficiency during gestation dysregulates dozens of proteins involved in brain development and leads to rat pups with increased brain size and enlarged ventricles, abnormalities similar to those found in autistic children. Children with the Williams Syndrome, who can have greatly elevated calcitriol levels in early infancy, usually have phenotypes that are the opposite of autism. Children with vitamin D deficient rickets have several autistic markers that apparently disappear with high-dose vitamin D treatment. Estrogen and testosterone have very different effects on calcitriol's metabolism, differences that may explain the striking male/female sex ratios in autism. Calcitriol down-regulates production of inflammatory cytokines in the brain, cytokines that have been associated with autism. Consumption of vitamin D containing fish during pregnancy reduces autistic symptoms in offspring. Autism is more common in areas of impaired UVB penetration such as poleward latitudes, urban areas, areas with high air pollution, and areas of high precipitation. Autism is more common in dark-skinned persons and severe maternal vitamin D deficiency is exceptionally common the dark-skinned.

CONCLUSION

simple Gaussian distributions of the enzyme that activates neural calcitriol combined with widespread gestational and/or early childhood vitamin D deficiency may explain both the genetics and epidemiology of autism. If so, much of the disease is iatrogenic, brought on by medical advice to avoid the sun. Several types of studies could easily test the theory.

Epilepsy in patients with pervasive developmental disorder not otherwise specified

Data on epilepsy in pervasive developmental disorder not otherwise specified are few and scanty. Seventy-seven patients with pervasive developmental disorder not otherwise specified were compared with 77 with autistic disorder, matched for age and sex. The 2 groups were divided into 3 subgroups each: A, without electroencephalography (EEG) paroxysmal abnormalities or epilepsy; B, with EEG paroxysmal abnormalities without epilepsy; and C, with epilepsy. Mild mental retardation (P < .01), pathological neurological examination (P < .05), cerebral lesions (P < .01), abnormal EEG background activity (P < .001), and associated genetic pathologies (P < .01) were more common in pervasive developmental disorder not otherwise specified. Familial antecedents for epilepsy prevailed in subgroup C (P < .01). Epilepsy occurred in 35.1% of patients with pervasive developmental disorder not otherwise specified, with no statistically significant difference compared with autistic disorder. The mean age of seizure onset was earlier (2 years 8 months) in pervasive developmental disorder not otherwise specified (P < .000). Seizure outcome was better in autistic disorder. Genetic diseases and cerebral lesions should be investigated in pervasive developmental disorder not otherwise specified to clarify the etiological and clinical features.

Autism with facial port-wine stain: a new syndrome?

The hallmark of Sturge-Weber syndrome is leptomeningeal angiomatosis. Over 15 years, four children were identified (2 boys, age 2.9-6 years) with unilateral facial port-wine stain, referred for presumable Sturge-Weber syndrome but who were also autistic. Computed tomography and magnetic resonance imaging scans failed to show evidence of leptomeningeal angioma in all four children. Three of the children had a history of seizures. Detailed neuropsychologic testing of three children revealed a similar presentation, characterized by developmental disturbance, particularly involving delayed onset of language, and early-emerging social atypicality. Positron emission tomography scanning of cerebral glucose metabolism revealed hypometabolism in the bilateral medial temporal regions, anterior cingulate gyrus, frontal cortex, right temporal cortex, and cerebellum. The pattern of glucose hypometabolism differed from that of 12 children with infantile autism (age 2.7-7.9 years) who had mild left medial temporal but more severe right temporal cortical hypometabolism and showed a reversal of normal frontotemporal asymmetry of glucose metabolism. Unilateral facial port-wine stain and autism with no intracranial angioma on conventional imaging may represent a rare clinical entity distinct from both infantile autism and previously described variants of Sturge-Weber syndrome.

Abnormal EEG lateralization in boys with autism

OBJECTIVE

Functional brain abnormalities associated with autism in 3-8-year-old boys were studied with EEG recorded under controlled experimental condition of sustained visual attention and behavioral stillness.

METHODS

EEG was recorded in two independent samples of boys with autism (BWA) from Moscow (N=21) and Gothenburg (N=23) and a corresponding number of age-matched typically developing boys (TDB). EEG spectral power (SP) and SP interhemispheric asymmetry within delta, theta and alpha bands were analyzed.

RESULTS

BWA comprised a non-homogeneous group in relation to theta and alpha SP. When four outliers were excluded the only between-group difference in absolute SP was a higher amount of prefrontal delta in BWA. BWA of both samples demonstrated atypical leftward broadband EEG asymmetry with a maximum effect over the mid-temporal regions. Concurrently, the normal leftward asymmetry of mu rhythm was absent in BWA.

CONCLUSIONS

The abnormal broadband EEG asymmetry in autism may point to a diminished capacity of right temporal cortex to generate EEG rhythms. The concurrent lack of normal leftward asymmetry of mu rhythm suggests that abnormalities in EEG lateralization in autism may be regionally/functionally specific.

SIGNIFICANCE

The data provide evidence for abnormal functional brain lateralization in autism.

EEG abnormalities in West syndrome: correlation with the emergence of autistic features

Autism may develop in children with West syndrome. This study was conducted to determine if EEG abnormalities in patients with West syndrome predict the later onset of autism. Two groups of patients with West syndrome, older than 6 years of age, were studied. One group consisted of those with a past history of West syndrome plus autism (N=14); the control group consisted of those with a past history of West syndrome but without autism (N=14). Patients were followed at regular intervals and video-EEG recordings were done. A total of 108 (autistic group) and 123 (non-autistic group) video-EEGs were examined. The two groups were compared with respect to age, presence or absence of hypsarrhythmia, and characteristics and localization of the epileptogenic foci. chi2 and Fisher's exact tests were used. The number of patients with at least one hypsarrhythmic EEG at the age of one year or later was significantly higher in autistic subjects (86%) than in non-autistic controls (29%). The incidence of EEGs with hypsarrhythmia was also higher in the autistic group, especially in older children (autistic, 49% versus non-autistic, 18% at age 3 years and later). Frontal predominance of the primary foci on EEGs with or without hypsarrhythmia was seen in 95.3% of the autistic group and 28.8% of the non-autistic group (p=0.001). Frontal abnormalities on the EEGs, which were mainly bilateral, and the persistence of hypsarrhythmia were significantly related to the emergence of autistic behavior in patients with West syndrome. These findings suggest that paroxysmal discharges in the cortical areas undergoing rapid maturation may be involved in the development of autistic features.

Abnormalities on the neurological examination and EEG in young children with pervasive developmental disorders

This study examined the nature and frequency of neurological and EEG abnormalities in 60 young children (ages 2-6 years) with pervasive developmental disorders. A number of standard neurological functions could not be adequately assessed due to the young age of the children and/or limited comprehension and cooperation. The most common neurological deficits were hyporeflexia, stereotypies, and hypotonia. EEG abnormalities were identified in 32% of the children while only two children were known to have clinical seizures. The frequency of cases with hypotonia or hyporeflexia was more common than in older children with this diagnosis. Results also indicate that EEG abnormalities are common in this young population but clinical seizures are rare, confirming other studies.

Epilepsy in autism spectrum disorders

Epilepsy is quite common in autism spectrum disorders, and it is increasingly recognized as an additional clinical problem that must be dealt with. The rate of comorbidity varies, depending upon the age and type of disorder, and currently the conservative estimate of comorbidity cases is 20-25% of the whole spectrum. Major risk factors for seizure occurrence are mental retardation and additional neurological disorders, as well as some specific associated medical conditions. Autism with regression has been reported in one-third of children with previously normal or nearly normal development. In an unknown proportion of these subjects, epileptic disorders are concomitant, leading to so-called autistic epileptiform regression. Furthermore, epileptiform abnormalities without seizures are frequent in this population and their role in the development of the nuclear disturbances of autism is controversial. The therapeutic approaches to epilepsy in autism are conventional treatments, yet when seizures are not evident, there is still controversy. Anticonvulsant medications could also potentially interfere with mood and behavioral disturbances frequently observed in ASD. The current understanding of the association between epilepsy and autism is still limited, but from a clinical point of view this association should not be overlooked, and it should be routinely investigated.

Medical investigation of children with autistic spectrum disorders

Few well-constructed studies have systematically evaluated medical investigation protocols for children with autistic spectrum disorders. This is in large part due to the heterogeneous nature of the population and changing diagnostic frameworks. This review outlines the studies that have directed investigation strategies to date, and discusses how these might be applied in the clinical situation. The importance of listing the conditions that may be present on the basis of the specific clinical presentation, and using a thorough history and examination to generate a pre-test probability of the target disorders is emphasized if tests are to be useful in directing therapy or broader management approaches.

Absence of seizures despite high prevalence of epileptiform EEG abnormalities in children with autism monitored in a tertiary care center

PURPOSE

Children with autism are commonly referred for video-EEG monitoring to determine the precise nature of their seizure-like events.

METHODS

We studied 32 children with autism by using continuous video-EEG telemetry (VEEG) monitoring at a tertiary care referral center.

RESULTS

Of the 32 total patients, 22 were primarily referred for seizure evaluation and 10 for 24-h interictal EEG recording. Studies in two additional patients were prematurely terminated because of intolerance (they are not included in the analyses). The median monitoring duration was 1 day (range, 1-7 days). Of 22 patients referred for seizure evaluation, 15 had recorded events, but none was an epileptic seizure; the other seven patients had no recorded events. Interictal epileptiform EEG abnormalities were detected in 19 (59%) of 32 patients. These abnormalities included focal sharp waves (in eight patients), multifocal sharp waves (in six patients), generalized spike-wave complexes (in 11 patients), and generalized paroxysmal fast activity/polyspikes (in two patients). Focal/multifocal and generalized epileptiform abnormalities coexisted in six patients. Notably, 11 (73%) of the 15 patients with nonepileptic events had interictal epileptiform EEG abnormalities.

CONCLUSIONS

Video-EEG evaluation of children with autism reveals epileptiform EEG abnormalities in the majority. However, many recorded seizure-like events are not epileptic, even in children with epileptiform EEG abnormalities.

Management of Landau-Kleffner syndrome

Landau-Kleffner syndrome (LKS) is an acquired epileptic aphasia disorder in which children, usually 3-8 years of age who have developed age-appropriate speech, experience language regression with verbal auditory agnosia, abnormal epileptiform activity, behavioral disturbances, and sometimes overt seizures. There are no controlled clinical trials investigating the therapeutic options for LKS. Only open-label data are available. Early diagnosis and initiation of prompt medical treatment appear to be important to achieving better long-term prognosis.Several antiepileptic drugs have been reported to be beneficial in treating this syndrome. These include valproic acid (valproate sodium), diazepam, ethosuximide, clobazam, and clonazepam. Reports on the efficacy of lamotrigine, sultiame, felbamate, nicardipine, vigabatrin, levetiracetam, vagal nerve stimulation, and a ketogenic diet are few and more experience is needed. Carbamazepine and possibly phenobarbital and phenytoin have been reported to occasionally exacerbate the syndrome. As initial therapy, valproic acid or diazepam is often empirically chosen. Subsequently, other antiepileptic drugs, corticosteroids, or intravenous immunoglobulin (IVIG) therapy are often used. Corticosteroid therapy should probably not be delayed more than 1-2 months after the initial diagnosis. Various corticosteroid regimens including oral prednisone and, recently, high doses of intravenous pulse corticosteroids, as well as corticotropin (adrenocorticotropic hormone) have been reported to be effective in LKS. Oral corticosteroids are used more often and usually need to be maintained for a long period of time to prevent relapses. The use of IVIG has been associated with an initial dramatic response in only a few patients. In our experience, a long-term worthwhile improvement has been noted in only 2 of 11 patients. These two patients had an immediate response to IVIG initially and after relapses before eventually achieving a long-term sustained remission. Surgical treatment by multiple subpial transection, which is reserved for patients who have not responded to multiple medical therapies, has been followed in selected cases by a marked improvement in language skills and behavior. However, a widely accepted consensus about suitable candidates for this surgery and about its efficacy is still lacking. Speech therapy, including sign language, and a number of classroom and behavioral interventions are helpful in managing LKS, and should be used in all patients.

Frequency of epileptiform EEG abnormalities in a sequential screening of autistic patients with no known clinical epilepsy from 1996 to 2005

Autism spectrum disorders (ASDs) affect 1 in 166 births. Although electroencephalogram (EEG) abnormalities and clinical seizures may play a role in ASDs, the exact frequency of EEG abnormalities in an ASD population that has not had clinical seizures or prior abnormal EEGs is unknown. There is no current consensus on whether treatment of EEG abnormalities may influence development. This retrospective review of 24-hour ambulatory digital EEG data collected from 889 ASD patients presenting between 1996 and 2005 (with no known genetic conditions, brain malformations, prior medications, or clinical seizures) shows that 540 of 889 (60.7%) subjects had abnormal EEG epileptiform activity in sleep with no difference based on clinical regression. The most frequent sites of epileptiform abnormalities were localized over the right temporal region. Of 176 patients treated with valproic acid, 80 normalized on EEG and 30 more showed EEG improvement compared with the first EEG (average of 10.1 months to repeat EEG).

Screening electroencephalograms in autism spectrum disorders: evidence-based guideline

The purpose of this study was to establish guidelines for the use of screening electroencephalograms (EEGs) in autism spectrum disorders to identify subclinical epileptiform activity. MEDLINE and EMBASE were searched for relevant articles. The evidence was reviewed using the methodology of the Canadian Task Force on Preventive Health Care. A priori criteria were established for article selection and for grading the quality and strength of the evidence. Seizures are common, occurring in 20 to 30% of patients based on the majority of studies. Epileptiform EEG abnormalities are present in 10.3% to 72.4% of patients and subclinical abnormalities in 6.1% to 31%. Evidence for the effectiveness of anticonvulsants and corticosteroids in reducing seizures and/or autistic symptoms is based primarily on case series and case reports, with only one published randomized trial. There is currently insufficient evidence to recommend for or against the use of screening EEGs in autistic patients. Given the frequency of seizure disorders in this patient population, a high index of clinical suspicion should be maintained for subtle symptoms of seizures.

AEDs and psychotropic drugs in children with autism and epilepsy

The efficacy of antiepileptic drugs (AEDs) and psychotropic medications in children with autism is limited to the treatment of seizures or to specific behaviors such as irritability, impulsivity, hyperactivity, repetitive behaviors, or aggression. The reliability and value of the available data--to determine the efficacy of these medications in autism--are limited by lack of controlled clinical trials, the small number of subjects, the heterogeneity of the population studied, and the brief duration of most drug trials. Indeed, few controlled clinical trials using AEDs in autism, with or without seizures, have been conducted. Because some AEDs also have a positive effect on mood, the benefits that children with autism sometimes obtain from these medications may not be due to the treatment of the abnormal electrical activity or the seizures per se but to an effect on common neuronal systems responsible for both behavior and epilepsy. The relationship between epilepsy and autism, and specifically the effects that abnormal electrical activity may have on the developing brain, may provide some valuable insights into the type of studies that are needed to help us understand the pathophysiology of autism.

A mixed epigenetic/genetic model for oligogenic inheritance of autism with a limited role for UBE3A

The genetic contribution to autism is often attributed to the combined effects of many loci (ten or more). This conclusion is based in part on the much lower concordance for dizygotic (DZ) than for monozygotic (MZ) twins, and is consistent with the failure to find strong evidence for linkage in genome-wide studies. We propose that the twin data are compatible with oligogenic inheritance combined with a major, genetic or epigenetic, de novo component to the etiology. Based on evidence that maternal but not paternal duplications of chromosome 15q cause autism, we attempted to test the hypothesis that autism involves oligogenic inheritance (two or more loci) and that the Angelman gene (UBE3A), which encodes the E6-AP ubiquitin ligase, is one of the contributing genes. A search for epigenetic abnormalities led to the discovery of a tissue-specific differentially methylated region (DMR) downstream of the UBE3A coding exons, but the region was not abnormal in autism lymphoblasts or brain samples. Based on evidence for allele sharing in 15q among sib-pairs, abnormal DNA methylation at the 5'-CpG island of UBE3A in one of 17 autism brains, and decreased E6-AP protein in some autism brains, we propose a mixed epigenetic and genetic model for autism with both de novo and inherited contributions. The role of UBE3A may be quantitatively modest, but interacting proteins such as those ubiquitinated by UBE3A may be candidates for a larger role in an oligogenic model. A mixed epigenetic and genetic and mixed de novo and inherited (MEGDI) model could be relevant to other "complex disease traits".

Epilepsy, electroencephalographic abnormalities, and regression in children with autism

The association of epilepsy and autism is recognized, and it has been reported at a percentage that varies between 8 and 42%, depending on age and diagnostic criteria. One third of autistic children undergo a regression of language and behavior between 2 and 3 years, and epileptiform abnormalities and epilepsy can be concomitant in an undetermined percentage of them. The aim of this study was to investigate the prevalence of epilepsy and paroxysmal abnormalities in a group of children with autism and to determine the percentage of regression course in this group. Forty-six patients with autism (mean age 7.8 +/- 2.7 years; 34 boys and 12 girls) were consecutively examined, and clinical evaluation, assessment, and electroencephalographic (EEG) recordings were performed in all of them. Thirty-five percent showed paroxysmal abnormalities and epilepsy, 22% had only paroxysmal abnormalities without seizures, and 13% of the children suffered from epilepsy. Sixty-five percent had a normal EEG. No difference in regression rate was observed between patients with paroxysmal abnormalities and epilepsy and those with a normal EEG and without seizures. In the study group, the prevalence of epilepsy was in the low range of individuals with autism, and different types of epilepsy were observed. Autism with regression was not influenced by paroxysmal abnormalities and epilepsy.

EEG and seizures in autistic children and adolescents: further findings with therapeutic implications

The goal of this study was to investigate the incidence of epilepsy and also the EEG findings among children with autism (A), a devastating disorder, and to compare these data to an EEG control group. EEGs were quantified as to the degree of epileptiform activity and also slow wave abnormalities. Abnormal EEGs were found in 75% of the 59 A children and 82% of their 151 EEGs; 46% had clinical seizures. Nearly all children with seizures had epileptiform activity, but almost 20% of those with spike discharges did not have clinical attacks. Slow wave abnormalities were more frequent and of a greater degree of severity in the A group, compared to controls. One new finding was that a greater variability of EEG abnormalities was found in the A group. Therapeutic implications, based on these latter findings, are discussed.

Behavioral and cellular consequences of increasing serotonergic activity during brain development: a role in autism?

The hypothesis explored in this review is that the high levels of serotonin in the blood seen in some autistic children (the so-called hyperserotonemia of autism) may lead to some of the behavioral and cellular changes also observed in the disorder. At early stages of development, when the blood-brain Barrier is not yet fully formed, the high levels of serotonin in the blood can enter the brain of a developing fetus and cause loss of serotonin terminals through a known negative feedback function of serotonin during development. The loss of serotonin innervation persists throughout subsequent development and the symptoms of autism appear. A review of the basic scientific literature on prenatal treatments affecting serotonin is given, in support of this hypothesis, with an emphasis on studies using the serotonin agonist, 5-methoxytryptamine (5-MT). In work using 5-MT to mimic hyperserotonemia, Sprague-Dawley rats are treated from gestational day 12 until postnatal 20. In published reports, these animals have been found to have a significant loss of serotonin terminals, decreased metabolic activity in cortex, changes in columnar development in cortex, changes in serotonin receptors, and "autistic-like" behaviors. In preliminary cellular findings given in this review, the animals have also been found to have cellular changes in two relevant brain regions: 1. Central nucleus of the amygdala, a brain region involved in fear-responding, where an increase in calcitonin gene related peptide (CGRP) was found 2. Paraventricular nucleus of the hypothalamus, a brain region involved in social memory and bonding, where a decrease in oxytocin was found. Both of these cellular changes could result from loss of serotonin innervation, possibly due to loss of terminal outgrowth from the same cells of the raphe nuclei. Thus, increased serotonergic activity during development could damage neurocircuitry involved in emotional responding to social stressors and may have relevance to the symptoms of autism.

Autism spectrum disorder: screening, diagnosis, and medical evaluation

Autism spectrum disorder (ASD) are a group of behaviorally defined neurodevelopmental disabilities with core deficits in socialization, communication, and behavior, although the presentation can be extremely variable. This article describes the core deficits in ASD, as well as the differential diagnosis and the more commonly associated comorbid disorders. The importance of early diagnosis is emphasized, and screening and assessment tools are reviewed. Finally, the role of the pediatric neurologist is discussed with regard to specific components of the evaluation, including history, physical examination, and ancillary testing.

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.

A systems neuroscience approach to autism: biological, cognitive, and clinical perspectives

Autism is a behaviorally defined disorder characterized by a broad constellation of symptoms. Numerous studies directed to the biological substrate demonstrate clear effects of neurodevelopmental differences that will likely point to the etiology, course, and long-term outcomes of the disorder. Consistently replicated research on the neural underpinnings of autism is reviewed. In general, results suggest several main conclusions: First, autism is a heterogeneous disorder and is likely to have multiple possible etiologies; second, structural brain studies have indicated a variety of diffuse anatomical differences, reflective of an early developmental change in the growth or pruning of neural tissue, rather than localized lesions; similarly, neurochemical studies suggest early, neuromodulatory discrepancies rather than gross or localized abnormalities; and finally, there are a number of limitations on studies of brain activity that to date preclude definitive answers to questions of how the brain functions differently in autism. The large number of active research programs investigating the cognitive neuroscience of autism spectrum disorders, in combination with the exciting development of new methodologies and tools in this area, indicates the drama and excitement of work in this area.

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.

Autism, macrocrania and epilepsy: how are they linked?

To evaluate the possible association of autistic disorder (AD), macrocrania and epilepsy, we performed a retrospective study comparing epileptic and non-epileptic AD patients with macrocrania, and AD patients with macrocrania to age- and sex-matched AD controls without macrocrania. We found macrocrania in 17.3% of 121 patients with AD. Epilepsy was not significantly more frequent in AD patients with macrocrania than in those without macrocrania. There were no significant differences in the other clinical characteristics studied except for epileptiform EEG abnormalities which were more often found in AD patients with epilepsy. AD with macrocrania and epilepsy is not a syndrome but may be a marker for a group of subjects with AD. A role for familial macrocrania needs further assessment.

Epileptic syndromes in childhood: clinical features, outcomes, and treatment

We reviewed the clinical features, outcome, and treatment of many of the epileptic syndromes that begin in the childhood from 2 to 12 years of age, using a review of the literature and personal experience, with most references to authoritative texts. The developmental tasks of childhood are centered on refinement of motor skills and development of complex intellectual and social skills. The childhood onset epilepsies can be divided into benign, intermediate, and catastrophic based on their impact on childhood development. The clearest benign epilepsy is benign rolandic epilepsy, which often does not require medication treatment. The definition of benign occipital epilepsy is still often vague. In the intermediate category, childhood absence epilepsy often has associated learning disorders and a poor social outcome. About 50% of children with cryptogenic partial seizures have a very benign course, even though their epilepsy syndrome is not well defined. Generalized epilepsy with febrile seizures plus (GEFS+) has a dominant inheritance with a defined defect in cerebral sodium channels, but varies considerably in severity within affected members of the same kindred. The catastrophic epilepsies in childhood all have an inconsistent response to AED treatment and include continuous spike-wave in slow sleep (with variable severity), Landau-Kleffner syndrome (with a confusing overlap with autistic regression), the Lennox Gastaut syndrome (with broad defining features), and myoclonic-astatic epilepsy (with important overlaps with Lennox-Gastaut). Many of the epilepsies that begin in childhood are benign. Others interfere seriously with cognitive and social development.

Behavioral aspects of epilepsy in children with mental retardation

Epilepsy and mental retardation, two relatively common childhood conditions, are both associated with a wide range of behavioral disorders. This article reviews the behavioral disturbances found in children with epilepsy, mental retardation, and both conditions. The behavioral disturbances found in children with epilepsy are associated with seizure-related, cognitive, developmental, and psychosocial factors. Although children with mental retardation also demonstrate a broad spectrum of behavioral disturbances, children with specific mental retardation syndromes have better-defined patterns of psychopathology. The presence of epilepsy and mental retardation seems to increase the severity of psychopathology. Further studies are needed, however, to define better the interaction of these two conditions and how they impact the behavior of children.

How often does routine pediatric EEG have an important unexpected result?

BACKGROUND

Electroencephalogram recordings are requested for the assessment of many childhood disorders. To assess the utility of the EEG in children, we studied how often routine EEG results can be correctly predicted from the EEG requisition.

METHOD

Five hundred consecutive initial EEG requests from the IWK Grace Health Centre from two time epochs were examined. All EEGs were 16 channel (10-20 electrode system). Based only on the requisition (patient demographics, referring physician, and reason for EEG), we coded our prediction of the result and then the actual result. When results were discordant from prediction, a judgment was made about the potential importance of the result.

RESULTS

Overall, EEG results were correctly predicted in 81%. Prediction for all nonepilepsy reasons was accurate in 91% (n=320) and 96% for paroxysmal nonepileptic events (n=158) but only 59% for epileptic disorders (n=141) (p<0.0001). Neurologists ordered 45% of EEGs, pediatricians 32%, and GP's 17%. Predictions were least accurate for neurologists' requests (p<0.006) however, neurologists were more likely to request EEG for epileptic disorders (p<0.0001). Age of the child and urban versus rural address did not affect the accuracy of prediction.

CONCLUSION

Results of routine pediatric EEG for most nonepilepsy reasons appear highly predictable and therefore, possibly of little value to an experienced clinician. When requested for epilepsy, this "ancient" test remains full of surprises.

Epilepsy in adolescents and young adults with autistic disorder

Since the first description by Kanner (1943) the association between autistic disorder (AD) and epilepsy has been observed in 4-42% of patients. Some authors reported that seizures prevailed in adolescence but a systematic investigation has never been undertaken. We examined retrospectively 60 patients divided into two groups (with and without epilepsy and EEG paroxysmal abnormalities) with AD unrelated to a congenital or acquired encephalopathy (mean age 17 years 2 months). The aim was to investigate epilepsy, EEG paroxysmal abnormalities and possible etiological factors. The prevalence of epilepsy was 38.3%, much higher than that in a normal population of a similar age (6.6 per thousand). The prevalence of EEG paroxysmal abnormalities without epilepsy was 6.7%, higher than that in a population of adolescents and adults with psychiatric pathologies (2. 6%). Seizure onset was after age 12 years in 66.7% of cases. The most common type of epilepsy was partial in 65.2% and four patients (17.4%) had a benign childhood epilepsy with centro-temporal spikes. At the last observation 44.4% of patients had been seizure-free for 2 years or more. There were no organic factors influencing the development of epilepsy but familial and personal antecedents, mental retardation and CT scan/MRI data may suggest an early brain dysfunction responsible for AD and epilepsy.

The screening and diagnosis of autistic spectrum disorders

The Child Neurology Society and American Academy of Neurology recently proposed to formulate Practice Parameters for the Diagnosis and Evaluation of Autism for their memberships. This endeavor was expanded to include representatives from nine professional organizations and four parent organizations, with liaisons from the National Institutes of Health. This document was written by this multidisciplinary Consensus Panel after systematic analysis of over 2,500 relevant scientific articles in the literature. The Panel concluded that appropriate diagnosis of autism requires a dual-level approach: (a) routine developmental surveillance, and (b) diagnosis and evaluation of autism. Specific detailed recommendations for each level have been established in this document, which are intended to improve the rate of early suspicion and diagnosis of, and therefore early intervention for, autism.

Is schizophrenia a risk factor for epilepsy or acute symptomatic seizures?

PURPOSE

The precise prevalence of epilepsies and seizures in patients with schizophrenia remains unclear.

METHODS

To assess the prevalence of epilepsy and of acute symptomatic seizures in schizophrenics, we conducted a survey in a urban sector of Marseilles that includes 56,910 inhabitants, among whom 1,154 had been treated for psychiatric disorders, including 460 for schizophrenia or paranoid disorder (PD) (DSM III-R 295 and 297.1, respectively; mean age, 41.9 years; range, 17-79 years; 215 men and 245 women).

RESULTS

All 460 patients were receiving long-term neuroleptic drug therapy, and 397 had been hospitalized at least once in the past year, whereas 63 were followed up as outpatients only. Seizures were present in the history of 12 patients: five had various forms of chronic epilepsy (four men, one woman; DSM III-R 295.1, one case; 295.3, two cases; 295.9, two cases), and three of these experienced seizures only after the onset of their psychiatric condition; five had acute symptomatic seizures (four men, one woman; 295.1, two cases; 295.3, 295.9, and 297.1, one case), and two had only pseudoepileptic events (both 295.3).

CONCLUSIONS

This survey shows that the prevalence of epilepsy and acute symptomatic seizures is comparatively low in patients with schizophrenia or PD (10.8 per thousand each, respectively), and that the prevalence of a history of seizures (21.7 per thousand in this study) is not particularly increased in this middle-aged population. In contrast to childhood-onset autistic disorders, schizophrenia or PD are not major risk factors for epilepsy or acute symptomatic epileptic seizures.

Gangliosides in cerebrospinal fluid in children with autism spectrum disorders

Gangliosides are sialic acid-containing glycolipids found in all cells, especially abundant in nerve cells and mainly situated on outer-membrane surfaces. The aim of this study was to provide data on the concentration of gangliosides in the CSF of children and adolescents with autism spectrum disorders (ASD) - 66 with autistic disorder, and 19 with other autism spectrum disorders. The comparison group consisted of 29 children and adolescents, whose CSF had been sampled to exclude acute infectious CNS disorder. The concentrations of the gangliosides GM1, GD1a, GD1b, and GT1b were determined using a microimmunoaffinity technique. The ASD group had a significantly higher concentration of ganglioside GM1 compared with the comparison group. The GM1 increase could not be explained as secondary to other clinical factors. Mean ganglioside levels did not differentiate subgroups with autistic disorder and those with a more atypical clinical picture, nor subgroups with known medical disorders and those with idiopathic autism. Altered patterns of gangliosides in the CNS might reflect important correlates of pathogenesis in autism.

The long-term course of autistic disorders: update on follow-up studies

The majority of children with autism show deviance and socially or psychiatrically handicapping conditions throughout life. Only a small proportion of those with classical childhood autism lead independent adult lives. Others, particularly those with 'high-functioning' autism and so-called Asperger syndrome will improve enough to live an independent adult life. The level of mental retardation and other comorbid conditions (such as medical syndromes and other neuropsychiatric disorders, including epilepsy) is important in predicting outcome. An IQ below 50 around school age predicts severe restriction of social and adaptive functioning in adult life. The absence of communicative speech at 5-6 years of age is indicative of a poorer long-term overall outcome. There is a clear co-variation between IQ and level of communication, but probably there is some prognostic factor in language development apart from this. Measures of flexibility and cognitive shifting abilities tend to be good predictors of social outcome in a few studies. There is a continued need for prospective, longitudinal studies of children with autism spectrum disorders, particularly in Asperger syndrome. The role of interventions of various kinds needs to be addressed in such studies.

Infantile spasms: III. Prognostic implications of bitemporal hypometabolism on positron emission tomography

Positron emission tomography (PET) of brain glucose utilization is highly sensitive in detecting focal cortical abnormalities in patients with infantile spasms even when the computed tomographic (CT) and magnetic resonance imaging (MRI) scans are normal. Of 110 infants with spasms evaluated for potential surgical intervention during an 8-year period, we encountered 18 infants (7 males, 11 females; age range, 10 mo to 5 yr) with a common metabolic pattern on positron emission tomography (PET) consisting of bilateral hypometabolism in the temporal lobes. CT and MRI scans did not reveal any focal abnormalities in the 18 infants. Video-electroencephalographic monitoring indicated either bilateral or multifocal epileptogenicity, or failed to show any epileptic focus, so that none of the 18 infants were considered candidates for resective surgery. These patients were then enrolled in a prospective study aimed at determining long-term outcome in the presence of bilateral temporal PET hypometabolism. Analysis of outcome in 14 of the 18 subjects (follow-up period, 10 mo to 10 yr 5 mo; mean, 3 yr 11 mo +/- 2 yr 4 mo [SD]) revealed the following: (1) all had severe developmental delay and had failed to gain significant milestones; (2) language development had been minimal or absent; (3) 10 of the 14 met the DSM-IV criteria for autistic disorder. Our findings indicate that patients with infantile spasms and bitemporal glucose hypometabolism on PET comprise a relatively homogeneous group and are typically not candidates for cortical resection. The long-term outcome of these infants is particularly poor and the majority are autistic.