Introduction: Epilepsy is more frequent in individuals with Autism Spectrum Disorder (ASD) than in the general population; however, its diagnosis is frequently challenging. Areas Covered: We report the current diagnostic criteria for both ASD and epilepsy. We describe the incidence, prevalence, and risk factors for epilepsy in patients with ASD. We then focus on the electro-clinical approach, including the clinical evaluation of cognitive regression. Expert Opinion: A diagnosis of epilepsy should be made based on the International League Against Epilepsy (ILAE) definition. A diagnosis of epilepsy should be established based on a single seizure with electroencephalography (EEG) abnormalities. Considering the high prevalence of EEG abnormalities in children with ASD without epilepsy, EEG should only be performed at epilepsy onset, and more precisely when a clinical interview has confirmed that repetitive paroxysmal events could be seizures. There are still many gaps in our understanding of epilepsy in patients with ASD. It would be of interest to further understand the links, if any, between EEG abnormalities and ASD phenotype. The identification of epilepsy syndromes in ASD would help analyze the possible underlying etiologies, for the administration of more appropriate antiepileptic drugs (AED), and to explain the prognosis to caregivers.
Keywords: Autism; Epilepsy; epileptic encephalopathy.