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.1 Symptoms must be present in early childhood and they must limit and impair everyday functioning.1 The Centers for Disease Control’s (CDC) Autism and Developmental Disabilities Monitoring (ADDM) Network estimates that approximately one in 88 children have ASD.2 Between 2007 and 2012, the prevalence estimate for parent-reported ASD among children in the United States aged 6 to 17 years increased to one in 55.3 Many children diagnosed with ASD also have other physical health, developmental, psychiatric, neurologic, and genetic diagnoses. Since autism was first described in the 1940s, research has proposed a model of central nervous system (CNS) dysfunction as the underlying origin for this disorder. In recent years, the focus has been on neuropathology as reflected in neuroimaging studies that have yielded results in favor of CNS etiology. It is divided into idiopathic ASD, which refers to cases in which children meet criteria for autism but do not have a comorbid associated medical disorder known to cause ASD, and syndromic ASD. Children diagnosed with syndromic ASD have an identifiable syndrome or medical disorder associated with the autism phenotype (eg, tuberous sclerosis complex).
There is an increased prevalence of epilepsy and/or epileptiform electroencephalography (EEG) abnormalities in children with ASD, and the association with other neurologic disorders in this population supports the CNS linkage. It is estimated that approximately one-third of children and adolescents with ASD experience seizures.4 Current evidence also suggests that seizure onset peaks bimodally in early childhood and again in adolescence.5
The relationship between epilepsy and autism is controversial. Is autism in some children the result of a malignant form of epilepsy, or is epilepsy simply the result of the underlying cause of the autism and epilepsy? What is the cause and effect relationship of subclinical epileptiform discharges in the EEG and continuous spike and wave in sleep on the behavioral phenotype? The concept of an epileptic encephalopathy is that “the epileptic activity itself may contribute to severe cognitive and behavioral impairments above and beyond what might be expected from the underlying pathology alone (eg, cortical malformation), and that these can worsen over time.”6 This concept attempts to encompass this controversy and implies that the natural history of the disorder is potentially modifiable by treatment.
With an increase in the prevalence of ASD and the limited subspecialty resources available in many areas, primary pediatricians are caring for this population more than in past years. The majority of children with autism and seizures are managed, at least in part, by a pediatrician and a pediatric neurologist. Care coordination and implementation of the medical home principle is of great importance for this subgroup of children with special health care needs.
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. Family centered care coordination and implementation of the medical home principle are explored within the context of this specific population of children with special health care needs.
Epidemiology of ASD
The lifetime co-occurrence of epilepsy and ASD is extremely variable and ranges from 5% to 46%.4 The prevalence of epilepsy in children with ASD is between 7% to 14%, and the cumulative prevalence by adulthood ranges from 20% to 35%7 (Figure 1). Even with conservative estimates, these prevalence rates are substantially higher than in the general population, and are the basis for confirming that ASD is a risk factor for the development of epilepsy.4 There appears to be a bimodal incidence of epilepsy, although not clearly defined, with one peak occurring in the preschool years (younger than 5 years) and a second peak in adolescence (older than 10 years).5 (Figure 1) For individuals with ASD and intellectual disability, prevalence rates of epilepsy of up to 21% have been reported and are 2.6 times more likely than for those children with ASD but without intellectual disability.8 Among children with ASD and severe intellectual disability (IQ < 55), the average age of seizure onset is 3.5 years. For those with mild intellectual disability (IQ 55–69), the average age of seizure onset is 7.2 years.8 Prevalence is related to both etiology and severity, and epilepsy is more prevalent in children with autism combined with cerebral palsy (27%) and cerebral palsy plus severe mental retardation (67%) than in those without.9 Syndromic autism and severe intellectual disability also occurred more often in individuals with epilepsy.10
Relationship between incidence of idiopathic autism and epilepsy. EEG = electroencephalogram.
Image courtesy of Amy Francis, DO.
Autism and Epilepsy
There is much controversy about the interplay between autism and epilepsy. To better understand this linkage, a review of terminology is imperative. A seizure is characterized as a transient abnormal, excessive, disorderly discharge of neurons primarily in the cerebral cortex.11 Clinically, seizures are paroxysmal, stereotyped, brief interruptions of behavior associated with electrographic seizure patterns.12 Nonconvulsive or subclinical seizures yield EEG abnormalities without clinically recognizable cognitive, behavioral, or motor patterns, or discernible loss of consciousness. Inter-ictal epileptiform activity is paroxysmal electrographic activity containing spike or sharp waves that interrupt the background.12 Epilepsy is defined as two or more unprovoked seizures of any type: generalized, focal, or unknown in origin.11 Therefore, febrile seizures and seizures resulting from acute illness, trauma, infection, or metabolic disturbances are not considered epilepsy. Epilepsy is further classified as electroclinical syndromes, nonsyndromic epilepsies with structural-metabolic causes, and epilepsies of unknown cause.11
The clinical diagnosis of seizures in children with autism can be challenging. Children with autism have many other behaviors that are not epileptic; therefore, video EEG is recommended to confirm that these behaviors are indeed epileptic. Many children display restricted and repetitive patterns of behaviors such as visual perspectiving and these, usually described as “staring episodes” by parents, can mimic absence seizures. Stereotypies are rigid heterogeneous behaviors that are inflexible and nonfunctional in nature, simple or complex, and are reported in 37% to 95% of individuals with ASD.13 They may include arm flapping, hand-finger mannerisms, body rocking, sniffing, or facial grimacing and occur without interruption of consciousness. They are often interpreted by caregivers as seizures. Note that in a report of 15 children with autism referred for seizure evaluation, none of the events recorded were epileptic seizures; however, 73% had EEG abnormalities.14
Seizure types associated with autism depend on age and etiology, and all seizure types have been reported. In one study, the most common type of clinical seizure reported in children with idiopathic autism was complex partial seizures typical of rolandic epilepsy.15 Other studies have reported that generalized tonic-clonic and atypical absence seizures were most common.16 Myoclonic and tonic-clonic seizures have also been reported.17 The overall incidence of epilepsy in children with ASD increases as the child ages.18 (Figure 1). Many researchers studying the association of autism and epilepsy tend to divide patients into three groups: patients without clinical seizures and EEG paroxysmal abnormalities, patients with EEG paroxysmal abnormalities but no clinical seizures, and patients with epilepsy.10,16 The second and third groups are more likely to have cerebral lesions and autistic regression. The occurrence of severe/profound mental retardation was also more frequent in the third group.
EEG findings vary. Paroxysmal epileptiform activity (PA) refers to both nonspecific changes, such as slowing and asymmetry, and epileptiform discharges consisting of spikes or sharp wave discharges, generalized spike-wave, generalized polyspikes, and polyspikes and waves. These subclinical EEG findings may occur in individuals without seizures, and their presence should not be considered evidence of epilepsy. Instead, these EEG changes are associated with cortical dysfunction and are observed in higher rates in individuals with ASD even in the absence of epilepsy.4 Reported rates of PA vary but are likely age-dependent, as they are more frequent at early ages (4 to 6 years) and decrease toward puberty15 (Figure 1). In a study of 106 patients, the prevalence of epilepsy and EEG PA without epilepsy was 23.6% and 18.9%, respectively, and a high proportion of fast activity, 40% and 36%, respectively, was noted.16 Focal and multifocal paroxysmal activity was mainly recorded on the centro-parietal-temporal regions. In the same study, 86 (24.9%) of 345 patients with ASD developed epilepsy. Focal epilepsy occurred in 37 patients (43%), generalized epilepsy occurred in 22 (25.6%), febrile convulsions occurred in 29 (33.7%), and epileptic encephalopathy (West Syndrome) occurred in five (5.8%).10 There does not seem to be a consistent pattern or frequency of epileptiform discharges reported.4
MRI findings also vary. Early studies using MRI to evaluate children with ASD showed hyperplasia in cerebral gray matter and cerebral and cerebellar white matter. This early overgrowth followed by abnormally slowed growth is thought to be the result of abnormal regulation of brain development.18 Small studies utilizing volumetric magnetic resonance analysis suggest abnormalities in the anatomy and connectivity of limbic–striatal or “social” brain systems that may contribute to the brain metabolic differences and behavioral phenotype in autism.19 In a study of 345 individuals with ASD, structural CNS abnormalities included white matter hyperintensities; posterior fossa abnormalities, including Arnold-Chiari type 1, Dandy-Walker malformations, and cerebellar hypoplasia; cortical malformations; and intracranial cysts and masses. Presence of neuroimaging findings was most likely in children with epilepsy (40.7%) compared to children with EEG PA without epilepsy (32.1%) and children without EEG PA and epilepsy (19.7%).10 Similar to EEG reports, there does not seem to be a consistent pattern of MRI changes reported.
For patients with ASD and epilepsy, early diagnosis and implementation of evidence-based multidisciplinary evaluations to promote communicative, regulatory, adaptive, learning, and social skills is required. This includes coordination and teamwork with interventions by occupational therapy, speech therapy, and early childhood educators knowledgeable about evidence-based behavioral and developmental therapies. Any child suspected to have ASD should be referred immediately for a comprehensive diagnostic evaluation. For those individuals who express a more severe autism phenotype with epilepsy, medical management and additional therapies are justified.
Antiepileptic drugs are the first-line approach to manage seizures in children with epilepsy.20 However, there are limited data about medication response in children with ASD and epilepsy, and there are no specific treatment guidelines. Most evidence has come from case reports and not randomized, controlled trials or large clinical studies. Valproic acid is most commonly used in this population. In one study of 176 patients with autism and epilepsy followed for almost a year, almost half (45%) of those treated with valproic acid normalized their EEG, and an additional 17% demonstrated improved EEG tracings compared to their baseline EEGs.21 Children with either ASD and seizures or ASD without clinical seizures but with EEG PA have shown improvement when treated with valproic acid.22 Other researchers have suggested that patients with ASD and abnormal EEG findings may be more likely to respond to divaproex sodium than patients with normal EEG findings. Interestingly, both groups showed greater improvements in aberrant behaviors than their placebo counterparts.23 Lamotrigene and levetiracetam are also used clinically in this population, but research findings have not consistently supported their effects of improving seizures or aberrant behaviors.24 Note that the immediate goal of medical treatment is seizure control, and all of the medications have behavioral and cognitive effects. Additionally, in the epileptic encephalopathies, improvement of the EEG may also be a goal of treatment.
The ketogenic diet has been used for almost a century to help control seizures and has been shown to be effective in treating multiple seizure types and epilepsy syndromes. It is important to remember that when the ketogenic diet is implemented, metabolic screening and monitoring are required, as is close monitoring of height and weight.25
Vagus Nerve Stimulation
Vagus nerve stimulation (VNS) has been approved by the U.S. Food and Drug Administration as a treatment method for medically refractory partial-onset seizures in patients 12 years of age and older. One study using the VNS epilepsy registry found that patients with ASD responded just as well as all other patient subgroups receiving VNS therapy, noting a decrease in seizure frequency and an improvement in several quality-of-life parameters, including alertness, school performance, and mood.26
The role of surgery in children with autism and epilepsy is uncertain, but the primary goal is seizure control.
Autism Phenotype and Epilepsy
Approximately one-third of caregivers of patients with ASD report language regression between 18 and 24 months of age. Autistic regression is considered regression of language skills and social-emotional development accompanying the onset of autistic behaviors. Children who experience developmental regression also have high rates of seizure disorders. Note that the role of seizures and epileptiform activity in autistic regression is controversial, but that children with autism are likely to regress prior to age 2 years.27
The classic epileptic encephalopathies potentially modifiable by treatment in addition to West Syndrome include Landau Kleffner Syndrome (LKS) and continuous spikes and waves during slow sleep. LKS is an acquired epileptic aphasia associated with clinical seizures or an epileptiform EEG. LKS typically occurs in mid-childhood and is characterized by an acquired aphasia, predominantly impacting the receptive language domain, followed by secondary impairment of expressive language. The EEG findings include spikes and sharp waves, or spike-wave discharges usually over the bi-temporoparietal regions.9 Both autism and LKS are associated with language regression in childhood, but children with LKS do not typically demonstrate impaired social interaction or restricted and repetitive behaviors. Additionally, language regression occurs later in childhood for children with LKS.
Tuberous sclerosis complex is a genetic neurocutaneous disorder characterized by hypopigmented macules, fibroangiomata, kidney lesions, CNS hamartomas, seizures, intellectual disability, and behaviors consistent with autism and/or attention deficit hyperactivity disorder. The autism features are associated with the tuber location and the epileptic activity recorded in those areas.28 ASD has been reported in up to 60% of clinical patients.28
Screening Recommendations for New Diagnosis Of ASD
The Autism Practice Parameter guideline of the American Academy of Neurology and Child Neurology Society recommends prompt referral for formal audiologic evaluation for children with speech and language delays.7 Laboratory investigations recommended for any child with developmental delay and/or autism should include lead screening. The American Academy of Pediatrics and the American Academy of Neurology guidelines do not recommend routine neuroimaging for patients with ASD, even in the presence of megalencephaly, unless focal neurological signs are present on exam. A sleep-deprived EEG is indicated when there is a reported history of seizure-like activity or in patients with significant regression in social and communication functions. Genetic testing in children with autism, microarray comparative genomic hybridization, and DNA analysis for fragile X should be considered as part of the initial diagnostic evaluation29,30 (Table 1).
Autism and Epilepsy: Take Home Points for Pediatricians
Epilepsy is common in children and young adults with autism, but the relationship is complicated and controversial. Though epilepsy is considered to be a negative prognostic factor for children with autism, advances in understanding specific genetic pathways underlying seizures and autism hold the promise of new treatments and improved long-term outcomes. Concurrent epilepsy and autism are strongly associated with lower cognitive and adaptive behavior levels. Remission rate of epilepsy in children with autism and intellectual disability is only 16%.8 Adults with epilepsy, autism, and intellectual disability experience lower adaptive functioning and encounter more barriers as they transition from pediatric to adult medical care.
Children with autism and seizures represent a unique group of children with special health care needs, and it is important for the general pediatrician to establish a medical home for this population. Early diagnosis and ongoing care coordination is necessary. Ensuring early intervention services, coordinating pediatric subspecialty referrals, managing medications, encouraging an appropriate educational experience, supporting parents, and planning for transition are key elements in providing a medical home for children with autism and seizures.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Washington, DC: American Psychiatric Association; 2013.
- Autism and Developmental Disabilities Monitoring Network Surveillance Year 2008 Principal Investigators; Centers for Disease Control and Prevention.Prevalence of Autism Spectrum Disorders — Autism and Developmental Disabilities Monitoring Network, 14 Sites, United States, 2008. Surveillance Summaries. MMWR Surveill Summ. 2012;61(3):1–19.
- Blumberg SJ, Bramlett MD, Kogan MD, et al. Changes in prevalence of parent-reported autism spectrum disorder in school-aged U.S. children: 2007 to 2011–2012. National Health Statistics Reports. 2013;65:1–11.
- Spence SJ, Schneider MT. The role of epilepsy and epileptiform EEGs in autism spectrum disorders. Pediatr Res. 2009;65(6):599–606. doi:10.1203/PDR.0b013e31819e7168 [CrossRef]
- Volkmar FR, Nelson DS. Seizure Disorders in Autism. J Am Acad Child Adolesc Psychiatry. 1990;29(1):127–129. doi:10.1097/00004583-199001000-00020 [CrossRef]
- Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005–2009. Epilepsia. 2010;51(4):676–685. doi:10.1111/j.1528-1167.2010.02522.x [CrossRef]
- Filipek PA, Accardo PJ, Ashwal S, et al. Practice parameter: Screening and diagnosis of autism Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society. Neurology. 2000;55(4);468–479. doi:10.1212/WNL.55.4.468 [CrossRef]
- Danielsson S, Gillberg IC, Billstedt E, et al. Epilepsy in young adults with autism: a prospective population-based follow-up study of 120 individuals diagnosed in childhood. Epilepsia. 2005;46(6):918–923. doi:10.1111/j.1528-1167.2005.57504.x [CrossRef]
- Tuchman R, Rapin I. Epilepsy in Autism. Lancet Neurol. 2002;1(6):352–358. doi:10.1016/S1474-4422(02)00160-6 [CrossRef]
- Parmeggiani A, Barcia G, Posar A, et al. Epilepsy and EEG paroxysmal abnormalities in autism spectrum disorders. Brain Dev. 2010;32(9):783–789. doi:10.1016/j.braindev.2010.07.003 [CrossRef]
- Fisher RS, van Emde Boas W, Blume W, et al. Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE). Epilepsia. 2005;46(4):470–472. doi:10.1111/j.0013-9580.2005.66104.x [CrossRef]
- Kelley RK, Moshe SL. Electrophysiology and epilepsy in autism. In: Autism: A Neurological Disorder of Early Brain Development. London: Mac Keith Press; 2006:160–173.
- Turner M. Annotation: Repetitive behavior in autism: A review of psychological research. J Child Psychol Psychiatry. 1999;40(6):839–849. doi:10.1111/1469-7610.00502 [CrossRef]
- Kim HL, Donnelly JH, Tournay AE, et al. Absence of seizures despite high prevalence of epileptiform EEG abnormalities in children with autism monitored in a tertiary care center. Epilepsia. 2006;47(2):394–398. doi:10.1111/j.1528-1167.2006.00434.x [CrossRef]
- Rossi PG, Posar A, Parmeggiani A. Epilepsy in adolescents and young adults with autistic disorder. Brain Dev. 2000;22(2):102–106. doi:10.1016/S0387-7604(99)00124-2 [CrossRef]
- Rossi PG, Parmeggiani A, Bach V, et al. EEG features and epilepsy in patients with autism. Brain Dev. 1995;17(3):169–174. doi:10.1016/0387-7604(95)00019-8 [CrossRef]
- Steffenburg S, Gillberg C, Steffenburg U. Psychiatric disorders in children and adolescents with mental retardation and active epilepsy. Arch Neurol. 1996;53(9):904–912. doi:10.1001/archneur.1996.00550090114017 [CrossRef]
- Courchesne E, Karns CM, Davis HR, et al. Unusual brain growth patterns in early life in patients with autistic disorder. An MRI study. Neurology. 2001;57(2):245–254. doi:10.1212/WNL.57.2.245 [CrossRef]
- McAlonan GM, Cheung V, Cheung C, et al. Mapping the brain in autism. A voxel-based MRI study of volumetric differences and intercorrelations in autism. Brain. 2005;128(Pt 2):268–276. doi:10.1093/brain/awh332 [CrossRef]
- Asconapé JJ. The selection of antiepileptic drugs for the treatment of epilepsy in children and adults. Neurol Clin. 2010;28(4) 843–852. doi:10.1016/j.ncl.2010.03.026 [CrossRef]
- Chez MG, Chang M, Krasne V, et al. Frequency of epileptiform EEG abnormalities in a sequential screening of autistic patients with no known clinical epilepsy from 1996 to 2005. Epilepsy Behav. 2006;8(1):267–271. doi:10.1016/j.yebeh.2005.11.001 [CrossRef]
- Plioplys AV. Autism: electroencephalogram abnormalities and clinical improvement with valproic acid. Arch Pediatr Adolesc Med. 1994;148:220–222. doi:10.1001/archpedi.1994.02170020106021 [CrossRef]
- Hollander E, Chaplin W, Soorya L, et al. Divalproex sodium vs. placebo for the treatment of irritability in children and adolescents with autism spectrum disorders. Neuropsychopharmacology. 2010;35(4):990–998. doi:10.1038/npp.2009.202 [CrossRef]
- Wasserman S, Iyenger R, Chaplin WF, et al. Levetiracetam versus placebo in childhood and adolescent autism: a double blind placebo-controlled study. Int Clin Psychopharmocol. 2006;21(6):363–367. doi:10.1097/01.yic.0000224787.13782.0f [CrossRef]
- Zupec-Kania B, Zupanc ML. Long-term management of the ketogenic diet: seizure monitoring, nutrition, and supplementation. Epilepsia. 2008;49(Suppl 8):23–26. doi:10.1111/j.1528-1167.2008.01827.x [CrossRef]
- Levy ML, Levy KM, Hoff D, et al. Vagus nerve stimulation therapy in patients with autism spectrum disorder and intractable epilepsy: results from the vagus nerve stimulation therapy patient outcome registry. J Neurosurg Pediatr. 2010;5(6):595–602. doi:10.3171/2010.3.PEDS09153 [CrossRef]
- Tuchman R. Autism and epilepsy: what has regression got to do with it?Epilepsy Curr. 2006:6(4):107–111. doi:10.1111/j.1535-7511.2006.00113.x [CrossRef]
- Wiznitzer M. Autism and tuberous sclerosis. J Child Neurol. 2004;19(9):675–679.
- Miller DT, Adam MP, Aradhya S, et al. Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies. Am J Hum Genet. 2010;86(5):749–764. doi:10.1016/j.ajhg.2010.04.006 [CrossRef]
- Shen Y, Dies KA, Holm IA. Clinical genetic testing for patients with autism spectrum disorders. Pediatrics. 2010:125(4),e727–e735. doi:10.1542/peds.2009-1684 [CrossRef]
Autism and Epilepsy: Take Home Points for Pediatricians
Lifetime co-occurrence of epilepsy and ASD ranges from 5% to 46%
Bimodal incidence and peaks at < 5 years and again > 10 years
Prevalence rates are higher for individuals with intellectual disability
First seizure occurs at younger age for individuals with intellectual disability
No consistent pattern of seizures
Focal seizures are most frequently reported
No consistent pattern of MRI changes
Neuroimaging findings are most likely in children with autism and epilepsy as well as children with EEG PA without epilepsy
Children with autism who do not have EEG PA have the least risk for neuroimaging abnormalities
Focal and multifocal paroxysmal epileptiform activity mainly in centro-parietal-temporal regions
Epilepsy is a negative prognostic factor for children with ASD
Concurrent epilepsy and autism are associated with lower cognitive and adaptive malfunctioning
Patients encounter more barriers as they transition from pediatric to adult medical care