EEG features and epilepsy in patients with autism

SPECT findings in autism spectrum disorders and medically refractory seizures

A high rate of seizures and electroencephalogram abnormalities has been noted in individuals with autism spectrum disorders (ASDs). Common underlying neurodevelopmental abnormalities may exist in the brains of individuals with both ASDs and epilepsy. Single-photon emission computed tomography (SPECT) studies of the brain have provided sensitive brain function findings. Such studies often reveal not only localized areas of hyperperfusion, which could be related to the seizure-onset zone, but also localized areas of hypoperfusion that may correlate with the focal reductions in function observed in the prefrontal lobes, cingulate gyrus, superior temporal gyrus, and mesial temporal lobes of many individuals with both ASDs and epilepsy. The focal neuronal dysfunction revealed by SPECT could be caused by aberrant neuronal connectivity. This article is part of a Special Issue entitled "Autism and Epilepsy".

Childhood autism spectrum disorders with and without epilepsy: clinical implications

This prospective cross-sectional study compared 25 children with pervasive developmental disorder and epilepsy and 25 children having pervasive developmental disorder without epilepsy on pervasive developmental disorder scores, Childhood Autism Rating Scale scores, language disability, presence of regression, and epileptiform abnormalities. Epilepsy phenotype was also studied. Children with pervasive developmental disorder and epilepsy had higher pervasive developmental disorder scores (P = .001), higher Childhood Autism Rating Scale scores (P = .016), and lower social quotient (P = .09). More than 50% of children with pervasive developmental disorder and epilepsy and 12% of children having pervasive developmental disorder without epilepsy had epileptiform abnormalities in electroencephalography (EEG). Regression of milestones was significantly associated with epilepsy and epileptiform abnormalities. Children with pervasive developmental disorder and epilepsy might have a worse developmental trajectory requiring intensive management. A behavioral phenotype of autism may coexist often in children with epilepsy, EEG abnormalities, and regression. Seizures might be difficult to control in these children despite adequate compliance. Studies with larger sample size and longitudinal follow-up will provide better understanding.

Limited role for routine EEG in the assessment of staring in children with autism spectrum disorder

AIM

The assessment of staring episodes in children with autism spectrum disorder (ASD) is difficult due to the range of diagnostic possibilities, the increased frequency of epileptiform activity on electroencephalogram (EEG), and the inability of normal EEG to exclude seizures. We reviewed the diagnostic use of routine EEG in this setting.

METHOD

The routine EEG database of the Royal Children's Hospital, Melbourne was searched for recordings during 2005-2010 in children with ASD below 16 years of age who were referred for staring. EEG reports and recordings were reviewed and epileptiform activity was characterised.

RESULTS

Ninety-two EEGs in children with ASD were requested for episodes of staring. No child had absence or focal dyscognitive seizures confirmed on EEG. Findings were normal or showed non-epileptiform abnormalities in 80 children. Interictal epileptiform abnormalities were recorded in 12 children, but were judged potentially significant in only three. Seven children had epileptiform activity typical of benign focal epilepsy of childhood, such discharges seen not uncommonly in developmentally normal and delayed children without seizures.

INTERPRETATION

Given the difficulties of performing EEG in children with ASD, the low yield of positive diagnostic findings and the high frequency of insignificant abnormalities, we suggest that EEG should be undertaken judiciously when evaluating children with ASD and staring episodes.

Incidence and behavioral correlates of epileptiform abnormalities in autism spectrum disorders

Autism spectrum disorders (ASD) are associated with an increased incidence of epilepsy and of epileptiform discharges on electroencephalograms. It is unknown whether epileptiform discharges correlate with symptoms of ASD. We completed a retrospective chart review of 101 patients with ASD who had overnight electroencephalograms. We looked for a relationship between epileptiform abnormalities and diagnosis, history of regression, communication skills, and other features associated with ASD. There was a higher incidence of epileptiform activity in children with stereotypies and aggressive behavior. The incidence of epileptiform abnormalities was significantly lower in Asperger's compared with more severe forms of autism. Results suggest that increasing severity of autistic symptoms may be associated with higher likelihood of epileptiform abnormalities. Whether treatment alters outcome is unknown.

Mice over-expressing BDNF in forebrain neurons develop an altered behavioral phenotype with age

Evidence from clinical studies suggests that abnormal activity of brain derived neurotrophic factor (BDNF) contributes to the pathogenesis of autism spectrum disorders (ASDs). A genetically modified line of mice over-expressing a BDNF transgene in forebrain neurons was used to investigate if this mutation leads to changes in behavior consistent with ASD. The mice used in these experiments were behaviorally tested past 5 months of age when spontaneous seizures were evident. These seizures were not observed in age-matched wildtype (WT) mice or younger mice from this transgenic line. The BDNF mice in these experiments weighed less than their WT littermates. The BDNF transgenic (BDNF-tg) mice demonstrated similar levels of sociability in the social approach test. Conversely, the BDNF-tg mice demonstrated less obsessive compulsive-like behavior in the marble burying test, less anxiety-like behavior in the elevated plus maze test, and less depressive-like behavior in the forced swim test. Changes in behavior were found in these older mice that have not been observed in younger mice from this transgenic line, which may be due to the development of seizures as the mice age. These mice do not have an ASD phenotype but may be useful to study adult onset epilepsy.

Using quantitative and analytic EEG methods in the understanding of connectivity in autism spectrum disorders: a theory of mixed over- and under-connectivity

Neuroimaging technologies and research has shown that autism is largely a disorder of neuronal connectivity. While advanced work is being done with fMRI, MRI-DTI, SPECT and other forms of structural and functional connectivity analyses, the use of EEG for these purposes is of additional great utility. Cantor et al. (1986) were the first to examine the utility of pairwise coherence measures for depicting connectivity impairments in autism. Since that time research has shown a combination of mixed over and under-connectivity that is at the heart of the primary symptoms of this multifaceted disorder. Nevertheless, there is reason to believe that these simplistic pairwise measurements under represent the true and quite complicated picture of connectivity anomalies in these persons. We have presented three different forms of multivariate connectivity analysis with increasing levels of sophistication (including one based on principle components analysis, sLORETA source coherence, and Granger causality) to present a hypothesis that more advanced statistical approaches to EEG coherence analysis may provide more detailed and accurate information than pairwise measurements. A single case study is examined with findings from MR-DTI, pairwise and coherence and these three forms of multivariate coherence analysis. In this case pairwise coherences did not resemble structural connectivity, whereas multivariate measures did. The possible advantages and disadvantages of different techniques are discussed. Future work in this area will be important to determine the validity and utility of these techniques.

Children with autism spectrum disorder and epilepsy

Autism spectrum disorder (ASD) is a biologically based neurodevelopmental disability characterized by qualitative and persistent deficits in social communication and social interaction and by the presence of restricted, repetitive, and stereotyped patterns of behavior. Symptoms must be present in early childhood and they must limit and impair everyday functioning. There is an increased prevalence of epilepsy and/or epileptiform electroencephalography (EEG) abnormalities in children with ASD. It is estimated that approximately one-third of children and adolescents with ASD experience seizures, but the relationship between epilepsy and autism is controversial. This article reviews the types of seizures associated with ASD, the EEG findings, and current treatment strategies. The article also describes syndromes associated with the autism phenotype and epilepsy.

The association between epilepsy and autism symptoms and maladaptive behaviors in children with autism spectrum disorder

Epilepsy is common in children with autism spectrum disorder (ASD) but little is known about how seizures impact the autism phenotype. The association between epilepsy and autism symptoms and associated maladaptive behaviors was examined in 2,645 children with ASD, of whom 139 had epilepsy, from the Simons Simplex Collection. Children with ASD and epilepsy had significantly more autism symptoms and maladaptive behaviors than children without epilepsy. However, after adjusting for IQ, only hyperactivity symptoms remained significantly increased (13% higher) in the epilepsy group. Among children with ASD without co-occurring intellectual disability, children with epilepsy had significantly more irritability (20% higher) and hyperactivity (24% higher) symptoms. This is the largest study to date comparing the autism phenotype in children with ASD with and without epilepsy. Children with ASD and epilepsy showed greater impairment than children without epilepsy, which was mostly explained by the lower IQ of the epilepsy group. These findings have important clinical implications for patients with ASD.

Resting state EEG abnormalities in autism spectrum disorders

Autism spectrum disorders (ASD) are a group of complex and heterogeneous developmental disorders involving multiple neural system dysfunctions. In an effort to understand neurophysiological substrates, identify etiopathophysiologically distinct subgroups of patients, and track outcomes of novel treatments with translational biomarkers, EEG (electroencephalography) studies offer a promising research strategy in ASD. Resting-state EEG studies of ASD suggest a U-shaped profile of electrophysiological power alterations, with excessive power in low-frequency and high-frequency bands, abnormal functional connectivity, and enhanced power in the left hemisphere of the brain. In this review, we provide a summary of recent findings, discuss limitations in available research that may contribute to inconsistencies in the literature, and offer suggestions for future research in this area for advancing the understanding of ASD.

Clinical characteristics of children with autism spectrum disorder and co-occurring epilepsy

OBJECTIVES

To estimate the prevalence of epilepsy in children with Autism Spectrum Disorder (ASD) and to determine the demographic and clinical characteristics of children with ASD and epilepsy in a large patient population.

METHODS

Cross-sectional study using four samples of children with ASD for a total of 5,815 participants with ASD. The prevalence of epilepsy was estimated from a population-based sample. Children with and without epilepsy were compared on demographic and clinical characteristics. Multivariate logistic regression was used to examine the association between demographic and clinical characteristics and epilepsy.

RESULTS

The average prevalence of epilepsy in children with ASD 2-17 years was 12.5%; among children aged 13 years and older, 26% had epilepsy. Epilepsy was associated with older age, lower cognitive ability, poorer adaptive and language functioning, a history of developmental regression and more severe ASD symptoms. The association between epilepsy and the majority of these characteristics appears to be driven by the lower IQ of participants with epilepsy. In a multivariate regression model, only age and cognitive ability were independently associated with epilepsy. Children age 10 or older had 2.35 times the odds of being diagnosed with epilepsy (p<.001) and for a one standard deviation increase in IQ, the odds of having epilepsy decreased by 47% (p<.001).

CONCLUSION

This is among the largest studies to date of patients with ASD and co-occurring epilepsy. Based on a representative sample of children with ASD, the average prevalence of epilepsy is approximately 12% and reaches 26% by adolescence. Independent associations were found between epilepsy and older age and lower cognitive ability. Other risk factors, such as poor language and developmental regression, are not associated with epilepsy after controlling for IQ. These findings can help guide prognosis and alert clinicians to patients with ASD who are at increased risk for epilepsy.

Can EEG characteristics predict development of epilepsy in autistic children?

BACKGROUND

The high occurrence of epilepsy in children with autism spectrum disorders (ASD) is a clear indication that ASD has a neurobiological basis. The current understanding of the association between epilepsy and ASD is still limited, but from a clinical point of view, this association should not be overlooked.

AIMS

We investigated the electroencephalogram (EEG) paroxysmal abnormality in children with ASD and the incidence of later development of epilepsy.

METHODS

Participants were recruited from University of Yamanashi hospital and 5 satellite hospitals between April 1, 2001 and March 31, 2005. EEG recordings and clinical evaluations were performed every 6 months for at least 6 years, focusing on paroxysmal abnormality. We scored the occurrence and the location of spikes and evaluated the relation with later development of epilepsy.

RESULTS

The prospective study included 21 patients with ASD (12 males and 9 females) between the ages of 3 and 6 years. EEG paroxysmal abnormalities were present in 11/21 patients (52.4%). In addition, six of 21 patients (28.6%) had epilepsy at some point in their lives. The presence of frontal paroxysms was significantly associated with later development of epilepsy compared with centrotemporal paroxysmus (p < 0.003). The type of seizure diagnosed was mainly partial; in particular, partial with secondary generalization in 4/6 (66.7%).

CONCLUSION

The presence of frontal paroxysms may indicate a higher risk of epilepsy in ASD.

The brain GABA-benzodiazepine receptor alpha-5 subtype in autism spectrum disorder: a pilot [(11)C]Ro15-4513 positron emission tomography study

GABA (gamma-amino-butyric-acid) is the primary inhibitory neurotransmitter in the human brain. It has been proposed that the symptoms of autism spectrum disorders (ASDs) are the result of deficient GABA neurotransmission, possibly including reduced expression of GABAA receptors. However, this hypothesis has not been directly tested in living adults with ASD. In this preliminary investigation, we used Positron Emission Tomography (PET) with the benzodiazepine receptor PET ligand [(11)C]Ro15-4513 to measure α1 and α5 subtypes of the GABAA receptor levels in the brain of three adult males with well-characterized high-functioning ASD compared with three healthy matched volunteers. We found significantly lower [(11)C]Ro15-4513 binding throughout the brain of participants with ASD (p < 0.0001) compared with controls. Planned region of interest analyses also revealed significant reductions in two limbic brain regions, namely the amygdala and nucleus accumbens bilaterally. Further analysis suggested that these results were driven by lower levels of the GABAA α5 subtype. These results provide initial evidence of a GABAA α5 deficit in ASD and support further investigations of the GABA system in this disorder. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.

Normal binocular rivalry in autism: implications for the excitation/inhibition imbalance hypothesis

Autism is characterized by disruption in multiple dimensions of perception, emotion, language and social cognition. Many hypotheses for the underlying neurophysiological basis have been proposed. Among these is the excitation/inhibition (E/I) imbalance hypothesis, which states that levels of cortical excitation and inhibition are disrupted in autism. We tested this theory in the visual system, because vision is one of the better understood systems in neuroscience, and because the E/I imbalance theory has been proposed to explain hypersensitivity to sensory stimuli in autism. We conducted two experiments on binocular rivalry, a well-studied psychophysical phenomenon that depends critically on excitation and inhibition levels in cortex. Using a computational model, we made specific predictions about how imbalances in excitation and inhibition levels would affect perception during two aspects of binocular rivalry: mixed perception (Experiment 1) and traveling waves (Experiment 2). We found no significant differences in either of these phenomena between high-functioning adults with autism and controls, and no evidence for a relationship between these measurements and the severity of autism. These results do not conclusively rule out an excitation/inhibition imbalance in the visual system of those with autism, but they suggest that such an imbalance, if it exists, is likely to be small in magnitude.

Risk factors for autistic regression: results of an ambispective cohort study

A subgroup of children diagnosed with autism experience developmental regression featured by a loss of previously acquired abilities. The pathogeny of autistic regression is unknown, although many risk factors likely exist. To better characterize autistic regression and investigate the association between autistic regression and potential influencing factors in Chinese autistic children, we conducted an ambispective study with a cohort of 170 autistic subjects. Analyses by multiple logistic regression showed significant correlations between autistic regression and febrile seizures (OR = 3.53, 95% CI = 1.17-10.65, P = .025), as well as with a family history of neuropsychiatric disorders (OR = 3.62, 95% CI = 1.35-9.71, P = .011). This study suggests that febrile seizures and family history of neuropsychiatric disorders are correlated with autistic regression.

Treatment with levetiracetam in a patient with pervasive developmental disorders, severe intellectual disability, self-injurious behavior, and seizures: a case report

Pervasive developmental disorder is characterized by various symptoms that often include self-injurious behavior (SIB). Episodes of SIB occur in the context of high emotional arousal, anger, or fear and may be related to epilepsy. We report the case of a 20-year-old man with pervasive developmental disorder presenting with SIB non-responsive to antipsychotic medication. Positron emission tomography showed a right temporoparietal hypometabolic focal lesion suggestive of an epileptic focus. Two weeks after initiation of levetiracetam (Keppra®), SIB disappeared, without recurrence 24 months later. Levetiracetam (Keppra®) may be beneficial for such patients.

Epilepsy in pervasive developmental disorder without brain MRI abnormalities

BACKGROUND

Epilepsy has been reported in patients with pervasive developmental disorder (PDD), with an incidence ranging from 5% to 40%; however most of the studies included patients with brain magnetic resonance imaging (MRI) abnormalities (e.g., tuberous sclerosis) and patients with epilepsy whose seizure onset was in the first year of life.

METHODS

We retrospectively examined 67 patients (45 males, 22 females) with PDD and epilepsy, who did not have brain MRI abnormalities. Patients who had seizures in the first year of life were excluded. We divided the patients into two groups: group A included 34 patients with an IQ<50, and group B included 33 patients with an IQ≥50.

RESULTS

The median age of epilepsy onset was higher in group A than group B (8.8 vs. 5.2 years, P<0.01). Only one patient (3%) in group A and nine patients (27%) in group B were classified with generalized epilepsy (P<0.05). At the last observation, 16 patients (47%) in group A and 25 patients (76%) in group B were seizure-free for ≥1year (not statistically significant).

CONCLUSION

The relationship between PDD and epilepsy may be different between patients with lower (group A) and higher (group B) IQs in patients who do not have brain MRI abnormalities.

Characteristics of compulsive tail chasing and associated risk factors in Bull Terriers

OBJECTIVE

To evaluate and define the characteristics of tail chasing in Bull Terriers and explore the association between tail chasing and other behavioral and physical characteristics.

DESIGN

Survey and case-control study.

ANIMALS

333 Bull Terriers (145 dogs with tail-chasing behavior and 188 unaffected dogs).

PROCEDURES

Owners of Bull Terriers with tail-chasing behavior were surveyed regarding the age of onset, triggers, frequency, duration, interruptability, degree of disruption to the dogs' normal functioning and the owners' relationship with the dog, and associated medical and physical consequences. Associations of tail chasing with various behavioral and physical characteristics were examined by comparison of dogs with tail-chasing behavior with unaffected dogs.

RESULTS

Phenotypic and developmental descriptions of tail chasing in Bull Terriers were defined. Associations of tail chasing with sex, trance-like behavior, and episodic aggression were found. Males were at an 8% greater risk for the diagnosis of tail chasing than females. Phobias and owner-directed aggression did not significantly associate with tail chasing in the final log-linear model, but did have significant associations in earlier analyses that did not include the behaviors of episodic aggression and trance-like behavior.

CONCLUSIONS AND CLINICAL RELEVANCE

In Bull Terriers with tail-chasing behavior, there was a slight increase in the susceptibility of males to develop tail-chasing behavior, compared with females. A close association of tail chasing with trance-like behavior and episodic aggression was identified.

Characterization of childhood-onset complex partial seizures associated with autism spectrum disorder

Autism spectrum disorder (ASD) has a close relationship with epilepsy. A previous study showed complex partial seizures (CPS) to be the most frequent type of epileptic seizures in cases of ASD. Patients with childhood-onset CPS were retrospectively studied to investigate the prevalence of ASD and to characterize the association between CPS and ASD. The study cohort comprised 86 patients with CPS manifesting at 1 to 9 years of age. Symptomatic CPS and Panayiotopoulos syndrome were excluded. Patients with ASD (ASD group) were compared with those without ASD (non-ASD group). Of the 86 patients with childhood-onset CPS, 36 (42%) also had ASD. This ASD group was predominantly male (68.6%), with higher rates of intellectual disability (69%), and reported frequent seizures (60% had monthly or more frequent seizures). CPS without secondary generalization were more common in the ASD group (69%) than in the non-ASD group (36%), as were frontal paroxysms on EEG (54.5% vs 30%, respectively). In the non-ASD group, 82% of cases had been seizure free for 2 or more years, in comparison to 50% in the ASD group. ASD is frequently associated with childhood-onset CPS. Male gender, cognitive deficits, frequent seizures, and frontal paroxysms are risk factors for the association of ASD with CPS.

Characteristics of late-onset epilepsy and EEG findings in children with autism spectrum disorders

Purpose

To investigate the clinical characteristics of late-onset epilepsy combined with autism spectrum disorder (ASD), and the relationship between certain types of electroencephalography (EEG) abnormalities in ASD and associated neuropsychological problems.

Methods

Thirty patients diagnosed with ASD in early childhood and later developed clinical seizures were reviewed retrospectively. First, the clinical characteristics, language and behavioral regression, and EEG findings of these late-onset epilepsy patients with ASD were investigated. The patients were then classified into 2 groups according to the severity of the EEG abnormalities in the background rhythm and paroxysmal discharges. In the severe group, EEG showed persistent asymmetry, slow and disorganized background rhythms, and continuous sharp and slow waves during slow sleep (CSWS).

Results

Between the two groups, there was no statistically significant difference in mean age (P=0.259), age of epilepsy diagnosis (P=0.237), associated family history (P=0.074), and positive abnormal magnetic resonance image (MRI) findings (P=0.084). The severe EEG group tended to have more neuropsychological problems (P=0.074). The severe group statistically showed more electrographic seizures in EEG (P=0.000). Rett syndrome was correlated with more severe EEG abnormalities (P=0.002). Although formal cognitive function tests were not performed, the parents reported an improvement in neuropsychological function on the follow up checkup according to a parent's questionnaire.

Conclusion

Although some ASD patients with late-onset epilepsy showed severe EEG abnormalities, including CSWS, they generally showed an improvement in EEG and clinical symptoms in the long-term follow up. In addition, severe EEG abnormalities tended to be related to the neuropsychological function.

The EL mouse: a natural model of autism and epilepsy

PURPOSE

Autism is a multifactorial disorder that involves impairments in social interactions and communication, as well as restricted and repetitive behaviors. About 30% of individuals with autism develop epilepsy by adulthood. The EL mouse has long been studied as a natural model of multifactorial idiopathic generalized epilepsy with complex partial seizures. Because epilepsy is a comorbid trait of autism, we evaluated the EL mouse for behaviors associated with autism.

METHODS

We compared the behavior of EL mice to age-matched control DDY mice, a genetically related nonepileptic strain. The mice were compared in the open field and in the light-dark compartment tests to measure activity, exploratory behavior, and restricted and repetitive behaviors. The social transmission of food preference test was employed to evaluate social communication. Home-cage behavior was also evaluated in EL and DDY mice as a measure of repetitive activity.

KEY FINDINGS

We found that EL mice displayed several behavioral abnormalities characteristic of autism. Impairments in social interaction and restricted patterns of interest were evident in EL mice. Activity, exploratory behavior, and restricted behavior were significantly greater in EL mice than in DDY mice. EL mice exhibited impairment in the social transmission of food preference assay. In addition, a stereotypic myoclonic jumping behavior was observed in EL mice, but was not seen in DDY mice. It is of interest to note that seizure activity within 24 h of testing exacerbated the autistic behavioral abnormalities found in EL mice.

SIGNIFICANCE

These findings suggest that the EL mouse expresses behavioral abnormalities similar to those seen in persons with autism. We propose that the EL mouse can be utilized as a natural model of autism and epilepsy.

Rare familial 16q21 microdeletions under a linkage peak implicate cadherin 8 (CDH8) in susceptibility to autism and learning disability

BACKGROUND

Autism spectrum disorder (ASD) is characterised by impairments in social communication and by a pattern of repetitive behaviours, with learning disability (LD) typically seen in up to 70% of cases. A recent study using the PPL statistical framework identified a novel region of genetic linkage on chromosome 16q21 that is limited to ASD families with LD.

METHODS

In this study, two families with autism and/or LD are described which harbour rare >1.6 Mb microdeletions located within this linkage region. The deletion breakpoints are mapped at base-pair resolution and segregation analysis is performed using a combination of 1M single nucleotide polymorphism (SNP) technology, array comparative genomic hybridisation (CGH), long-range PCR, and Sanger sequencing. The frequency of similar genomic variants in control subjects is determined through analysis of published SNP array data. Expression of CDH8, the only gene disrupted by these microdeletions, is assessed using reverse transcriptase PCR and in situ hybridisation analysis of 9 week human embryos.

RESULTS

The deletion of chr16: 60 025 584-61 667 839 was transmitted to three of three boys with autism and LD and none of four unaffected siblings, from their unaffected mother. In a second family, an overlapping deletion of chr16: 58 724 527-60 547 472 was transmitted to an individual with severe LD from his father with moderate LD. No copy number variations (CNVs) disrupting CDH8 were observed in 5023 controls. Expression analysis indicates that the two CDH8 isoforms are present in the developing human cortex.

CONCLUSION

Rare familial 16q21 microdeletions and expression analysis implicate CDH8 in susceptibility to autism and LD.

The effect of seizure disorder on symptom presentation in atypically developing children and children with autism spectrum disorders based on the BDI-2

PURPOSE

Autism Spectrum Disorders (ASD) and seizures are highly comorbid conditions. However, little research has been done to examine this relationship. The purpose of the current study was to examine the effect that seizure disorder has on symptom presentation in children with autism spectrum disorders as compared to atypically developing children.

METHOD

The Battelle Developmental Inventory, Second Edition (BDI-2) was used as a measure of impairment across adaptive, personal-social, communication, motor and cognitive skills.

RESULTS

A MANOVA indicated significant main effects between diagnostic group and seizure status, without a significant interaction. Follow-up univariate tests were conducted.

CONCLUSIONS

Overall, results indicated that children with ASD were more impaired than atypically developing children. In addition, children with seizures tended to be more impaired than children without seizures.

Epilepsy in autism: A pathophysiological consideration

Eighty cases of idiopathic autism with epilepsy and 97 cases without epilepsy were studied to evaluate the pathophysiology of epilepsy in autism. The initial visit to this clinic ranged 8months-30years 3months of age, and the current ages are 5years 8months-42years 3months, 60% reaching to over 30years of age. The average follow up duration is 22.2years±9.4years. The ages of onset of epilepsy were from 7months to 30years of age, with the two peaks at 3.2years and 16.7years. EEG central focus appeared earlier than frontal focus. Abnormality of locomotion and atonic NREM were observed more frequently in epileptic group. These suggest the neuronal system related to abnormality of locomotion and atonic NREM, which are the hypofunction of the brainstem monoaminergic system, is the pathomechanism underling the epilepsy in autism. By showing the abnormal sleep-wake rhythm and locomotion being the very initial symptoms in autism, we had shown the hypofunction of the brainstem monoaminergic system is the initial pathomechanism of autism. Thus, epilepsy in autism is not the secondary manifestation, but one of the pathognomonic symptoms of autism. The brainstem monoaminergic system project to the wider cortical area, and the initial monoaminergic hypofunction may lead to the central focus which appears earlier. The failure of the monoaminergic (serotonergic) system causes dysfunction of the pedunculo-pontine nucleus (PPN) and induces dysfunction of the dopamine (DA) system, and with development of the DA receptor supersensitivity consequently disinhibits the thalamo-frontal pathway, which after maturation of this pathway in teens cause the epileptogenesis in the frontal cortex.

Brain perfusion SPECT and EEG findings in children with autism spectrum disorders and medically intractable epilepsy

OBJECTIVE

We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both autism spectrum disorders (ASD) and medically intractable epilepsy.

METHODS

Fifteen children aged 4-16 years underwent multimodal examinations (MRI, interictal and/or ictal ECD-SPECT, EEG and MEG) to investigate their indications for surgical treatment. All children were diagnosed with ASD according to DSM-IV criteria and intractable epilepsy. Despite medical treatment for more than a year, all experienced at least one seizure per month. All had no underlying basic disorders. Each SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). The relationship between the eZIS pattern and EEG abnormalities or clinical symptoms was investigated.

RESULTS

All children showed focal abnormal patterns on eZIS and focal spikes on EEG. In all children, eZIS revealed a mixed hypoperfusion pattern, especially in the prefrontal cortex, medial frontal cortex, anterior cingulate cortex, medial parietal cortex, and/or anterior temporal cortex. In seven of 12 children who underwent interictal SPECT studies, areas of hypoperfusion were related to the focus observed on EEG; in six children, the focal EEG spikes represented areas of hyperperfusion. The children were divided into two groups according to the main type of hypoperfusion patterns seen on eZIS; medial-cingulate type and temporal type. No significant relationship was observed between the areas of hypoperfusion and clinical symptoms. eZIS showed the epileptic focus clearly on ictal SPECT.

CONCLUSIONS

SPECT was useful to detect the abnormal brain region not only in searching for the epileptic focus but also in assessing the low or high functioning region of the brain.

Clinical features of epilepsy with pervasive developmental disorder

PURPOSE

To clarify the clinical features of patients with epilepsy and pervasive developmental disorder (PDD).

METHODS

We examined 12 outpatients with epilepsy as well as PDD at Seiai Rehabilitation Hospital.

RESULTS

The patients comprised 7 males and 5 females. The initial neurological symptoms appeared between 5 months and 4 years of age. The interval between the initial neurological symptoms/developmental delay and seizure onset ranged from several months to twenty years. The seizures started at 10-19 years of age in 8 out of the 12 cases. The types of seizures were astatic-drop in 2 cases, tonic-to-astatic in one, atypical absence (decreased consciousness) and generalized tonic clonic seizures (GTCS) in 3 cases, GTCS in 4 cases, or myoclonic and psychomotor in 2 cases. The mental development distributed from normal to extremely severe retardation. Paroxysmal abnormalities on eegs were focal at the frontal area in 7 cases (58%) and other findings in 5 cases. Presumptive risk factors were prenatal in 6 cases (family history for PDD in 1 case, for epilepsy in 1, twin pregnancy in 2 cases, and other in 2 cases), perinatal in 2 patients, postnatal in 1, and unknown in 3 cases.

CONCLUSIONS

The seizures occurred most frequently after the onset of neurological symptoms or developmental delay. The frontal lobe dysfunction was associated with seizure onset in 58% of the cases based on the EEG findings. The risk factors were prenatal in 50% of the cases.

Epilepsy and EEG paroxysmal abnormalities in autism spectrum disorders

The occurrence of epilepsy in autism is variable; nevertheless, EEG paroxysmal abnormalities (PA) are frequently recorded in patients with autism, although the influence of epilepsy and/or EEG PA on the autistic regression has not been clarified yet. We examine a large sample of 345 inpatients with autism, divided into three groups: (1) patients without epilepsy and EEG PA; (2) patients with EEG PA but no seizures; (3) patients with epilepsy including febrile convulsions. The prevalence of epilepsy (24.9%) and EEG PA (45.5%) was higher than that reported in the general population. The significant differences among the three groups concerned autistic regression (comparison between groups 1 and 2, p<0.05; comparison between groups 1 and 3, p<0.01), cerebral lesions (comparison between groups 1 and 2, p<0.05; between groups 1 and 3, p<0.001), and symptomatic autism (comparison between groups 1 and 2 as much as comparison between groups 1 and 3, p<0.001), which were prevalent in groups 2 and 3; while severe/profound mental retardation was more frequent in group 3 compared to group 1 (p<0.01). Focal epilepsy (43.0%) and febrile convulsions (33.7%) were frequent in the third group with epilepsy. EEG PA were mainly localized in temporal and central areas (31.4%). Only 2.6% of patients had subcontinuous/continuous EEG PA during sleep. Seizures and EEG PA were not related to autistic regression. EEG PA occurred mainly in childhood, while epilepsy tended to occur (p<0.001) as age increased. The age at onset of seizures had two peaks: between 0 and 5 and between 10 and 15 years with no difference between idiopathic and symptomatic cases. In 58.5% of subjects aged > or = 20 years, epilepsy including febrile seizures occurred at some point of their lives, while cases with only EEG PA were less frequent (9.7%). The relationship among autism, EEG PA and epilepsy should be clarified and investigated. In autism, seizures and EEG PA could represent an epiphenomenon of a cerebral dysfunction independent of apparent lesions.

Autism and epilepsy: historical perspective

Autism spectrum disorders (ASD) and epilepsy co-occur in approximately 30% of individuals with either ASD or epilepsy. While there is no single unifying ASD-epilepsy phenotype, understanding potential commonalities in subgroups of children with an ASD-epilepsy phenotype will help us disentangle the pathophysiology of both ASD and epilepsy. Throughout this brief historical perspective we selectively review critical trends in ASD-epilepsy research and highlight challenges to clinical and research efforts including terminology, heterogeneity of both ASD and epilepsy, and lack of careful characterization of children affected with both ASD and epilepsy. These complex issues continue to burden research on the diagnosis, neurobiology and management of children with ASD and epilepsy. A key concept that has emerged during the past 40 years is the strong association between intellectual disability and a higher prevalence of epilepsy in individuals with ASD. In addition, the two peaks of seizure onset, one in early childhood and one in adolescence and continuing through adulthood may be unique to individuals with ASD. The overlap of language and autistic regression to epilepsy, EEG epileptiform activity, sleep, and to epileptic encephalopathies such as Landau-Kleffner syndrome continue to be controversial areas of research and of clinical interest. An emerging consensus is that shared developmental genetic, molecular and pathophysiological mechanisms exist and account for the common co-occurrence of ASD and epilepsy.

Frequent association of autism spectrum disorder in patients with childhood onset epilepsy

Autism spectrum disorder (ASD) has a close relationship with epilepsy. This study retrospectively examined patients with epilepsy associated with ASD. Among the 519 patients with epilepsy, 79 patients (15.2%) had ASD. Sixty-two patients had idiopathic ASD and 17 had secondary ASD. The epilepsy patients with idiopathic ASD were retrospectively analyzed. There were 47 males and 15 females, ranging from 2 to 43 years of age (median 11 years). The most frequent age at the onset of seizures was 4 years, and 85% occurred before 10. ASD was detected after the onset of epilepsy in 29 cases (46.8%), and eight of them had been overlooked for more than five years. Most of these were high-functioning ASD cases. The most frequent type of seizure was a complex partial seizure (CPS; 68%). Paroxysmal activities on EEG were localized in the frontal area in about half of the cases. Multiple anti-epileptic drugs were used in 33.8% cases (two in 17.7%, three in 16.1%), and 67.3% of the patients were seizure-free for more than two years. An amelioration of the autistic symptoms occurred after epilepsy treatment in five cases (8%). CPS with frontal paroxysms occurring from one to nine years of age seems to be characteristic of epilepsy associated with ASD.

Paroxysmal EEG abnormalities and epilepsy in pervasive developmental disorders: follow-up study until adolescence and beyond

This study examined paroxysmal abnormalities and epilepsy in EEG for individuals with pervasive developmental disorders (PDD) in two parts: first with a large number of subjects (n=1624); and second with extracted subjects followed from 5 years into adolescence and beyond (n=92). Many paroxysms in PDD patients in their childhood tended to appear at various sites and the same held for paroxysms at the time of epilepsy onset. However, in adolescence and beyond, paroxysms in the frontal region prevailed as those appearing at sites other than the frontal region tended to disappear. The same held for paroxysms at the time of epilepsy onset. These paroxysms in the frontal area characteristic of PDD were named "Paroxysms at F." It was suggested that functional abnormality in the frontal region exists in PDD through paroxysmal EEG abnormalities and epilepsy.

Detection of abnormalities for diagnosing of children with autism disorders using of quantitative electroencephalography analysis

Quantitative electroencephalography (qEEG) has been used as a tool for neurophysiologic diagnostic. We used spectrogram and coherence values for evaluating qEEG in 17 children (13 boys and 4 girls aged between 6 and 11) with autism disorders (ASD) and 11 control children (7 boys and 4 girls with the same age range). Evaluation of qEEG with statistical analysis demonstrated that alpha frequency band (8-13 Hz) had the best distinction level of 96.4% in relaxed eye-opened condition using spectrogram criteria. The ASD group had significant lower spectrogram criteria values in left brain hemisphere, (p < 0.01) at F3 and T3 electrodes and (p < 0.05) at FP1, F7, C3, Cz and T5 electrodes. Coherence values at 171 pairs of EEG electrodes indicated that there are more abnormalities with higher values in the connectivity of temporal lobes with other lobes in gamma frequency band (36-44 Hz).

Medical comorbidities in autism: challenges to diagnosis and treatment

Ever since its original description by Leo Kanner in l943, autism has been generally defined by its clinical characteristics and core symptoms that include impaired social skills, isolated areas of interest, and delayed and disordered language. Over time, it has become apparent that autism is a heterogeneous disorder with regard to its clinical presentation, etiology, underlying neurobiology, and degree of severity. As a result, the termed diagnosis of autism spectrum disorders (ASDs) has come into common usage. With advancements in clinical care, there has come the appreciation that many ASD children, adolescents, and adults may have medically relevant disorders that may negatively impact their developmental progress and behavior, but which frequently go undetected. Many of these medical conditions are treatable, often resulting in improved developmental gains and quality of life for the patient and family. In addition, the possibility exists that some of these medical conditions may suggest the presence of important genetic and/or biologic markers, which, if identified, can refine our ability to be more precise in categorizing clinical and genetic subtypes within the autism spectrum.

Limitations in life participation and independence due to secondary conditions

The effects of secondary conditions across adults with autism, Down syndrome, and cerebral palsy were explored in terms of overall limitation in life participation and independence, changes over time, and the degree and nature of limitation in specific secondary conditions. Information was obtained for 35 adults with autism, 49 with Down syndrome, and 29 with cerebral palsy (N = 113). Caregivers completed a questionnaire exploring secondary conditions on two occasions. Participants with cerebral palsy experienced the greatest overall limitations of the three groups. This finding is due to several secondary conditions. There were no changes in limitation scores over time. Implications related to health care for these groups are discussed.

"All that spikes is not fits", mistaking the woods for the trees: the interictal spikes--an "EEG chameleon" in the interface disorders of brain and mind: a critical review

Recent research into mammalian cortical neurophysiology, after 6 decades of Berger's seminal work on electroencephalography, has shifted the older concept of interictal epileptiform activity (IEA) away from that of a mere electrographic graphoelement of relevance to diagnostic implications in epilepsy. Instead, accumulating information has stressed the neuropsychological implications, cognitive and/or behavioral consequence of these electrophysiological events, which are the phenotypic expression of aberrations of actual biophysical cellular function. We feel that this review is germane to neuropsychiatry, however, a rather neglected area of research. There is a great scope for brain-behavior-EEG research in the future that can be complimented by other techniques of "neurobehavioral electrophysiology". This review does not address the "pearls, perils and pitfalls" in the use of EEG in epilepsy, but critically and systematically reappraises the published electroencephalographic correlates of human behavior. We reiterate that epileptiform and other paroxysmal EEG dysrhythmias unrelated to clinical seizures do have neuropsychological, cognitive and/or behavioral implications as seen in the various neuropsychiatric and neurobehavioral disorders discussed in this article. IEA and EEG dysrhythmias should neither be ignored as irrelevant nor automatically attributed to epilepsy. The relevance of these EEG aberrations in the disorders of the brain-mind interface extend beyond epilepsy, and may be an electrophysiological endophenotype of aberrant neuronal behavior indicative of underlying morpho-functional brain abnormalities. Magnetoencephalography (MEG), data fusion models (EEG-fMRI-BOLD), transcranial magnetic stimulation (TMS), evoked potentials (EP); intracranial electrophysiology, and EEG neurofeedback complemented by current functional neuroimaging techniques (fMRI and PET) would certainly help in further understanding the broader relationship between brain and behavior.

Epileptiform discharges in psychiatric patients: a controversy in need of resurrection

The current view of the psychiatric significance of inter-ictal spike discharges (IIS) in nonepileptic, psychiatric patients is that the discharges are "incidental" and are of no clinical significance. Hence, despite a voluminous literature suggestive that such discharges may have clinical relevance, electroencephalograms are hardly ever recorded in nonepileptic psychiatric patients. This literature is briefly summarized, and one detailed example of a disorder (i.e., autistic spectrum disorders) where such discharges are particularly common is provided. The argument is made that this is an area of psychiatry that is under-investigated and that research devoted to elucidating the mechanisms of development of IIS, their possible clinical relevance, and the role of anticonvulsants in managing such patients, could be very profitable.

EEG and MRI findings and their relation with intellectual disability in pervasive developmental disorders

BACKGROUND

The diagnostic category pervasive developmental disorders (PDDs) refer to a group of five disorders: autism, Rett syndrome, childhood disintegrative disorder, Asperger syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS). EEG abnormalities and seizures are considered much frequent in autistic subjects with comorbid intellectual disability (ID). In this study, we aimed to evaluate the EEG and MRI findings and their relation with ID in pervasive developmental disorder.

METHODS

A retrospective, cross-sectional and non-experimental study was performed. Subjects included 81 patients diagnosed with autism or PDD-NOS according to the DSM-IV criteria. The age range of the patients was 2-15 years (mean 6.6 years, SD 3.0). Among them, 21 (25.9%) were girls and 60 boys (74.1%).

RESULTS

Patients with severe ID had a higher rate of EEG abnormalities (P=0.03) than patients without ID as well as patients with mild or moderate ID. The association remained significant after the structural MRI abnormalities were controlled (P=0.04). The severity of ID was not associated with abnormal MRI. The most frequent EEG and MRI abnormalities were active epileptic anomaly/paroxysmal abnormality and cerebral atrophy/periventricular leukomalacia, respectively. Almost a third of the EEG abnormalities were associated with temporal cortex and adjacent cortical structures.

CONCLUSIONS

Consistent with previous studies, almost a fourth of the patients in this relatively large sample of patients with pervasive developmental disorders had EEG and/or MRI abnormalities. EEG results indicate that temporal cortex may play a significant role in pervasive developmental disorders.

The role of epilepsy and epileptiform EEGs in autism spectrum disorders

Autism is a neurodevelopmental disorder of unknown etiology characterized by social and communication deficits and the presence of restricted interests/repetitive behaviors. Higher rates of epilepsy have long been reported, but prevalence estimates vary from as little as 5% to as much as 46%. This variation is probably the result of sample characteristics that increase epilepsy risk such as sample ascertainment, lower intelligence quotient (IQ), the inclusion of patients with nonidiopathic autism, age, and gender. However, critical review of the literature reveals that the rate in idiopathic cases with normal IQ is still significantly above the population risk suggesting that autism itself is associated with an increased risk of epilepsy. Recently, there has been interest in the occurrence of epileptiform electroencephalograms (EEGs) even in the absence of epilepsy. Rates as high as 60% have been reported and some investigators propose that these abnormalities may play a causal role in the autism phenotype. Although this phenomenon is still not well understood and risk factors have yet to be determined, the treatment implications are increasingly important. We review the recent literature to elucidate possible risk factors for both epilepsy and epileptiform EEGs. We then review existing data and discuss controversies surrounding treatment of EEG abnormalities.

The role of epilepsy and epileptiform EEGs in autism spectrum disorders

Autism is a neurodevelopmental disorder of unknown etiology characterized by social and communication deficits and the presence of restricted interests/repetitive behaviors. Higher rates of epilepsy have long been reported, but prevalence estimates vary from as little as 5% to as much as 46%. This variation is probably the result of sample characteristics that increase epilepsy risk such as sample ascertainment, lower intelligence quotient (IQ), the inclusion of patients with nonidiopathic autism, age, and gender. However, critical review of the literature reveals that the rate in idiopathic cases with normal IQ is still significantly above the population risk suggesting that autism itself is associated with an increased risk of epilepsy. Recently, there has been interest in the occurrence of epileptiform electroencephalograms (EEGs) even in the absence of epilepsy. Rates as high as 60% have been reported and some investigators propose that these abnormalities may play a causal role in the autism phenotype. Although this phenomenon is still not well understood and risk factors have yet to be determined, the treatment implications are increasingly important. We review the recent literature to elucidate possible risk factors for both epilepsy and epileptiform EEGs. We then review existing data and discuss controversies surrounding treatment of EEG abnormalities.

Differences in the clinical presentation of Trisomy 21 with and without autism

BACKGROUND

Autism occurs 10 times more often in children with Down syndrome than in the general population, but diagnosing co-occurring autism in Down syndrome with severe intellectual disability is challenging. The objective of this case-control study was to identify characteristics differentiating children with trisomy 21 with and without autism and to determine the extent to which severe cognitive impairment affects the measures of autism symptomatology.

METHOD

Twenty children with trisomy 21 and autism (cases) were compared with children with trisomy 21 without autism (controls) matched on chronologic age, race and gender. Communication, cognitive and adaptive behaviour skills were assessed with standardized instruments. Medical history was reviewed and medical records were examined for early head growth. Scores on the diagnostic algorithm of the Autism Diagnostic Interview--Revised (ADI-R) were compared after adjusting for cognitive ability as measured by the Stanford-Binet (Fifth Edition) non-verbal change sensitive score.

RESULTS

Cases performed significantly more poorly on all assessments. Mean case-control differences for matched pairs were all significant at P < 0.0001 for receptive and expressive language skills, cognitive skills and adaptive skills. Seven cases had a history of seizures compared with one control(P = 0.01). After adjusting for cognitive ability, the mean scores on the Reciprocal Social Interaction, Communication, and Restricted, Repetitive and Stereotyped Behaviours domains of the ADI-R diagnostic algorithm remained significantly higher in cases compared with controls (P < 0.0001). All participants had decreased head size consistent with Down syndrome, with no case-control differences.

CONCLUSION

Children with trisomy 21 and autism have significantly more impaired brain function than children with trisomy 21 without autism. However, the deficits in the core domains of social reciprocity and communication, and the restricted and repetitive interests are not entirely explained by the more severe cognitive impairment. This autism phenotype in children with trisomy 21 which includes an increased risk for seizures may indicate a widespread loss of functional connectivity in the brain.

Convulsing toward the pathophysiology of autism

The autisms and epilepsies are heterogeneous disorders that have diverse etiologies and pathologies. The severity of impairment and of symptoms associated with autism or with particular epilepsy syndromes reflects focal or global, structurally abnormal or dysfunctional neuronal networks. The complex relationship between autism and epilepsy, as reflected in the autism-epilepsy phenotype, provides a bridge to further knowledge of shared neuronal networks that can account for both the autisms and the epilepsies. Although epilepsy is not a causal factor for autism, increased understanding of common genetic and molecular biological mechanisms of the autism-epilepsy phenotype has provided insight into the pathophysiology of the autisms. The autism-epilepsy phenotype provides a novel model to the study of interventions that may have a positive modulating effects on social cognitive outcome.

Epilepsy in autism is associated with intellectual disability and gender: evidence from a meta-analysis

BACKGROUND

The association between epilepsy and autism is consistently reported, with a wide range of prevalence rates. This may be attributed to the heterogeneity of the samples with respect to age, comorbidity, sex, and intellectual disability (ID). We aimed to compare the prevalence of epilepsy 1) among autistic patients with ID versus autistic patients without ID and 2) among male versus female autistic patients.

METHODS

We reviewed all data available from published reports (1963-2006) on autism and epilepsy and conducted a meta-analysis of 10 and 14 studies, respectively, to assess the relative risk (RR) of epilepsy in autism according to ID and gender. The pooled groups included 2112 (627 with IQ > or = 70, 1485 with IQ < 70) and 1530 (1191 male, 339 female) patients, respectively.

RESULTS

There was a strong discrepancy in relative risk (RR) according to IQ, with more autistic patients with ID having epilepsy (RR = .555; 95% confidence interval [CI]: .42-.73; p < .001). The pooled prevalence of epilepsy was 21.5% in autistic subjects with ID versus 8% in autistic subjects without ID. There was a strong discrepancy in RR according to sex, favoring comorbidity of epilepsy in autistic girls (RR = .549; 95% CI: .45-.66; p < .001). The male:female ratio of autism comorbid with epilepsy was close to 2:1 whereas the male:female ratio of autism without epilepsy was 3.5:1.

CONCLUSIONS

The results of this meta-analysis indicate that risk for epilepsy in autism is a function of ID severity and distinguishes autism associated with epilepsy as a subgroup of autism by its male-female ratio.

An investigation of sleep characteristics, EEG abnormalities and epilepsy in developmentally regressed and non-regressed children with autism

This study investigated sleep of children with autism and developmental regression and the possible relationship with epilepsy and epileptiform abnormalities. Participants were 104 children with autism (70 non-regressed, 34 regressed) and 162 typically developing children (TD). Results suggested that the regressed group had higher incidence of circadian rhythm disorders than non-regressed children. The regressed group showed higher Children's Sleep Habits Questionnaire Bedtime Resistance, Sleep Onset Delay, Sleep Duration and Night-Wakings scores. Epilepsy and frequent epileptiform EEG abnormalities were more frequent in regressed children. Past sleep disorders and a history of developmental regression were significantly associated with sleep disorders. This study is an initial step in better understanding sleep problems in regressed children with autism, further studies are necessary to better investigate these aspects.