Autism Spectrum Disorder with and without epilepsy: comparative analysis of 207 subjects

Background: 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 behavioural patterns. 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 experiences seizures, but the relationship between epilepsy and ASD is controversial.Methods: This study considers the data of 207 subjects with ASD, 45 of which developed during their life an Epilepsy, received at Child Neurology and Psychiatry Unit of University Hospital of Verona.We collected following data: sex, age, personal history, gestational age, birth weight, Apgar, head circumference at birth, prenatal, perinatal and postnatal complications, psychomotor development, ADI (Autism Diagnostic Interview-Revised), ADOS (Autism Diagnostic Observation Schedule), IQ and GQ (WISC-III, WPPSI, Leiter-R, Griffith’s scales), neurological examination, head circumference at visit time, dimorphisms, malformations, discolorations, head circumference at visit time, lateralization, age of onset of epilepsy, semiology of seizures, antiepileptic treatment, EEG, MRI and genetic exams.By comparing Autistic patients with and without epilepsy, the aim is to identify variables associated with higher risk of developing epilepsy.Results: 45 of 207 (21,74%) subjects developed an epilepsy. The male:female ratio is 6:1 in the group without epilepsy (group A) and 5.4:1 in the group with epilepsy (group AE). Average age for group A was 11.8 years, 15.1 years for group B. The average age of diagnosis of ASD is of 52.16 months for group A and 44.23 for the group AE. The onset of epilepsy in patients of group AE is 74.81 months. The mean gestational age of group A is 38.77 weeks, of group AE of 38.95 weeks. The preterm infants in group A are 13,46% and 11.36% in group AE. For group A the average value for Apgar is 8.7 and 3% of the subjects the score is lower than 6; for group AE the average value for Apgar is 8.3 and 13,95% of the subjects the score is lower than 6. Analysing developmental milestones can be seen that in group A the 19,74% of the individuals have developmental delay compared with 44% of group AE.In group A the 52,28% of subjects developed language, while in Group AE, the percentage drops dramatically to 28.8%.The average IQ in the group A is 56.36% (74.6% with mental retardation), while in group AE is 44.01 (93.02% with mental retardation).In group A MRI identified abnormalities in 38.7% of subjects, while in group AE in 73.3% of subjects.Genetic tests have identified genetic abnormalities in 35.75% for group A and in 39.4 & for group AE.In group A we recorded EEG abnormalities in 38.26% of cases (focal abnormalities 71,67%; generalized abnormalities 28,33%); in group AE we recorded EEG abnormalities in 90,9% of cases (focal abnormalities 84,2%; generalized abnormalities18,4%).Focusing on the group B, 86.36% subjects have partial seizures, 13,63% have generalized seizures. 4 subjects have no need of therapy, 22 have seizure control with one AED, 17 need an add-on.Conclusions: 1) The prevalence of epilepsy in patients with ASD is of 21.74%. This is a result strongly influenced by age and by the criteria of selection of the sample.2) Abnormal psychomotor development is a risk factor for the development of epilepsy in individuals with ASD.3) The low IQ is a risk factor for the development of epilepsy.4) EEG abnormalities are more common the epilepsy itself in autistic children and they are correlated with autistic regression.5) The central-temporal anomalies are the most common in individuals with ASD without epilepsy, frontal abnormalities in patients with epilepsy.6) Abnormalities on MRI are much more common in people with autism and epilepsy and are therefore an important risk factor.7) Genetic abnormalities are a very important factor and deserve a thorough investigation. In this study the difference between the two groups is low, but indicates a greater presence of genetic abnormalities in the group with epilepsy. We will need more specific genetic investigations to identify not only deletions and duplications but also mutations of DNA.8) Seizures in individuals with ASD do not have peculiar semeiological characteristics, they are more frequent partial seizures and the common treatments are effective.9) It is currently debated the usefulness of a screening program for epilepsy in individuals with ASD. Our opinion is that Autistic children with low IQ and/or abnormalities on MRI should undergo an EEG and their parents should be educated on the management of epilepsy.The correlation between Epilepsy and Autism is not entirely clear. Therefore we believe that research, especially in genetics, can help us understand the pathogenic mechanisms underlying these conditions.