Absence of Seizures Despite High Prevalence of Epileptiform EEG Abnormalities in Children with Autism Monitored in a Tertiary Care Center

Abstract

Summary:Purpose: Children with autism are commonly referred for video-EEG monitoring to determine the precise nature of their seizure-like events.Methods: We studied 32 children with autism by using continuous video-EEG telemetry (VEEG) monitoring at a tertiary care referral center.Results: Of the 32 total patients, 22 were primarily referred for seizure evaluation and 10 for 24-h interictal EEG recording. Studies in two additional patients were prematurely terminated because of intolerance (they are not included in the analyses). The median monitoring duration was 1 day (range, 1-7 days). Of 22 patients referred for seizure evaluation, 15 had recorded events, but none was an epileptic seizure; the other seven patients had no recorded events. Interictal epileptiform EEG abnormalities were detected in 19 (59%) of 32 patients. These abnormalities included focal sharp waves (in eight patients), multifocal sharp waves (in six patients), generalized spike-wave complexes (in 11 patients), and generalized paroxysmal fast activity/polyspikes (in two patients). Focal/multifocal and generalized epileptiform abnormalities coexisted in six patients. Notably, 11 (73%) of the 15 patients with nonepileptic events had interictal epileptiform EEG abnormalities.Conclusions: Video-EEG evaluation of children with autism reveals epileptiform EEG abnormalities in the majority. However, many recorded seizure-like events are not epileptic, even in children with epileptiform EEG abnormalities.

GABA and Glutamate Receptors of the Autistic Brain

“…Such an imbalance would reduce the ratio signal to noise of the sensory and procedural information in mild cases (Casanova et al, 2006) and, in the extreme ones, it could lead to epilepsy. Actually, the incidence of epilepsy in one third of people with autism (Tuchman & Rapin, 2002) and the presence of paroxystic activity in the electroencephalogram (EEG) of approximately 68% of autistic people (Kim et al, 2006) is consistent with this hypothesis. These gradual alterations of the EEG traces suggest that aberrant electrical activity in the autistic brain is expressed as a continuum and www.intechopen.com it may be present even in cases of autism with normal EEG recordings.…”

Autistic characteristics in adults with epilepsy

“…More recently, higher rates have been detected possibly influenced by improved detection methods, with the highest rates found in overnight EEG recordings (ibid.). A high rate of IED's has been detected without epilepsy even in the presence of a high rate of non-epileptic seizures in children with ASD (Kim, Donnelly, Tournay, Book, and Filipek, 2006).…”

Epilepsy and Autism

“…In addition to an increased prevalence of epilepsy in individuals with ASD, there is also a marked increased incidence of epileptiform activity on the EEGs of people with ASD (Giovanardi et al 2000;Hrdlicka et al 2004;Canitano et al 2005;Gabis et al 2005;Hughes and Melyn 2005;Baird et al 2006;Chez et al 2006;Kim et al 2006;Akshoomoff et al 2007;Hara 2007;Parmeggiani et al 2007;Giannotti et al 2008;Spence and Schneider 2009). Whereas interictal spikes occur in .5% of normally developing children without a history of epilepsy (EegOlofsson et al 1971), more recent studies have shown that up to 60% of EEG records from children with ASD have interictal spikes (Hughes and Melyn 2005) and many of the children with abnormal EEGs do not have a history of epilepsy (Hughes et al 2015).…”