1. Seizures and epilepsy and their relationship to autismspectrum disordersResearch in Autism SpectrumDisorders 3 (2009) 9991005Brian Wells, MPH, MSM

2. Autism Spectrum Disorders Autism spectrum disorders (ASD) are five relatedconditions that all share core symptoms of social andcommunication deficits as well as rituals andstereotypies Accompanying these core symptoms are often a host ofothers problems and disabilities. Among these difficulties are comorbid psychopathology,challenging behaviors, and other neurodevelopmentaldisorders such as intellectual disabilities Given the neurodevelopmental origins of ASD, and themany complicating factors that accompany it, the factthat ASD puts the individual at risk for seizures andepilepsy as well should come as no surprise 3. Autism Spectrum Disorders Another concern regarding seizure and epilepsyproblems in ASD is simply the large number ofpersons who display them. Furthermore, thesenumbers have been increasing in recent years. Onset of ASD is in early childhood, the numbersare large, and the condition is life long 4. Autism Spectrum Disorders Seizures of all types occur in persons with ASD Two or more seizures of any type (usually within a 3-year period) that are not environmentally induced(e.g., trauma, infection, alcohol withdrawal) aredescribed as epilepsy Prevalence studies of epilepsy and seizures in generalare highly variable for the ASD population. Rates havebeen reported from 5% to 38% There have not been many prevalence studies onepilepsy and ASD to date, and most of those haveincluded small sample sizes. This factor may at least in part account for the fact thatconsiderable variability exists in the current prevalencedata. 5. Autism Spectrum Disorders Prior studies Rossi et al. (2000) - 60 inpatients from 12 to 29 years ofage with autism. 38.3% of their ASD group evincedseizures/epilepsy. The 38% figure was also reported byDanielsson, Gillberg, Billstedt, Gillberg, and Olsson (2005)who studied 120 autistic children. Saemundson, Ludvigsson, Hilmarsdottir, and Rafusson(2007) found seizures in 37% of their 84 autistic childsample Gabis, Pomeroy, and Andriola (2005) report a co-occurrence of seizures/epilepsy and ASD at 40%. Gillberg (1987) reported rates of about 1/3 for persons withASD and seizures/epilepsy. Finally, on the high end of the seizure/epilepsy and ASDoverlap, Oslejskova et al. (2008) report a 40% rate. 6. Autism Spectrum Disorders A substantial number of studies have concludedthat the overlap in seizures and ASD is about 30%of cases or more. However, a few studies have reported very lowoverlaps in these problems. Pavone et al. (2004) reported epilepsy in subgroups with and without comorbid conditions. Reported 355% of the sample by group, with epileptic seizures occurring much more frequently where comorbid disorders were present. They concluded that seizures were likely due to comorbidity of other disorders and underlying brain dysfunction versus autism. 7. Nosology Autistic children with seizures/epilepsy in, general,have lower IQ, less adaptive behavior, moreemotional problems, and higher psychiatric druguse. EEG paroxysmal abnormalities and/or febrileconvulsions be used to define the disorder inpersons with autism. In their sample of 106 persons with autism they found the same types of epilepsy seen in the typically developing populations, with idiopathic forms being more common. Finally, 45% of these individuals first began experiencing seizures after 10 years of age. 8. Noslogy Abnormal EEG patterns appear to be a common method ofdescribing seizure and epileptiform activity in persons withASD High prevalence of these abnormal EEG and seizures plus thegeneral view that ASD has an underlying neurodevelopmentalcause, suggests possible similar neurological pathwaysacross these disorders. However, abnormal EEGs in ASD do not serve as a means ofsubtyping ASD To date, there is a lack of descriptive data on the appearanceof seizures in ASD. Some efforts at looking at EEG patterns have emerged, and itappears that all forms of seizures appear in ASD, although athigher rates than seen in the general population. 9. Etiology The general consensus is that ASD isneurodevelopmental in origin. It is furtherhypothesized that central nervous systemdysfunction is neurobiological in origin, thusexplaining high rates of abnormal EEG andseizures in ASD This argument is bolstered by the presence of othercentral nervous system dysfunctions at higher ratesthan seen in the general population One explanation for this overlap ofseizures/epilepsy and ASD is an imbalancebetween excitatory (glutamate) and inhibitorycomponents of neurobiology (gamma aminobutyricacid, GABA). 10. Austistic Regression Some have hypothesized that regression fromrelatively normal development up to age 2024months may be related to seizure activity. It is known that regression in language isassociated with seizures or abnormal EEG activity Up to a third of autistic children may regress Confusions persist over various definitions ofsimilar disorders to ASD. Acquired epileptic aphasia and Landau-Kleffner Syndrome (LKS) are often confused with autistic regression due to nonspecific language determination 11. Autistic Regression Several authors have proposed a direct linkbetween epilepsy and autistic regression. But, theirdata is correlational and clear cause and effectrelationships are yet to be established. Shinnar et al. (2001) studied 177 children with language regression. They concluded that regression earlier than age 3, and being male were most likely to be associated with autism. Seizures were more common in children over 3 years who regressed but were less likely to be autistic. Finally, they noted that regression in language was highly correlated to regression in other aspects of functioning such as cognitive and social behavior. 12. Conclusion ASD co-occurs with a host of problems such as intellectualdisability Challenging behaviors are often associated with ASD, as iscomorbid psychopathology With respect to seizures, researchers have found that whilethese disorders are neurological in origin they can be affectedby environmental variables and overlapping conditions. The picture is complex with respect to understanding thecauses of the event. Cause/effect links between seizures and epilepsy to ASD mayoccur in the future. At present, much more needs to be learned. Having said that,the clinician should be aware of this high co-occurrence duringassessment and intervention.