Can EEG characteristics predict development of epilepsy in autistic children?
Department of Paediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
The high occurrence of epilepsy in children with autism spectrum disorders (ASD) is a clear indication that ASD has a neurobiological basis. The current understanding of the association between epilepsy and ASD is still limited, but from a clinical point of view, this association should not be overlooked.
We investigated the electroencephalogram (EEG) paroxysmal abnormality in children with ASD and the incidence of later development of epilepsy.
Participants were recruited from University of Yamanashi hospital and 5 satellite hospitals between April 1, 2001 and March 31, 2005. EEG recordings and clinical evaluations were performed every 6 months for at least 6 years, focusing on paroxysmal abnormality. We scored the occurrence and the location of spikes and evaluated the relation with later development of epilepsy.
The prospective study included 21 patients with ASD (12 males and 9 females) between the ages of 3 and 6 years.
EEG paroxysmal abnormalities were present in 11/21 patients (52.4%). In addition, six of 21 patients (28.6%) had epilepsy at some point in their lives.
The presence of frontal paroxysms was significantly associated with later development of epilepsy compared with centrotemporal paroxysmus (p < 0.003). The type of seizure diagnosed was mainly partial; in particular, partial with secondary generalization in 4/6 (66.7%).
The presence of frontal paroxysms may indicate a higher risk of epilepsy in ASD.
Further reading by same authors
EEG characteristics predict subsequent epilepsy in children with febrile seizure.
Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
The role of electroencephalography (EEG) in the work-up of febrile seizure (FS) remains controversial.
We investigated the importance of EEG characteristics, especially the localizations of paroxysmal discharges, as predictors for subsequent epilepsy. Patients were referred from the outpatient department for EEG within 7-20 days after the seizure.
EEGs were classified as paroxysmally abnormal based on the presence of spikes, sharp waves, or spike-wave complexes, whether focal or generalized, that were considered abnormal for age and state.
Of 119 patients with FS, 26 (21.8%) revealed paroxysmal abnormality on EEG and 9 (7.6%) developed epilepsy.
Of nine patients with later epilepsy, 6 (66.7%) revealed paroxysmal EEG abnormality.
Of 26 patients with paroxysmal abnormality, 6 (23.1%) developed epilepsy.
Of 10 patients with generalized paroxysmal spike and wave activity, one (10%) developed epilepsy.
Of seven patients with rolandic discharge (RD), two (28.5%) developed epilepsy.
Of four patients with paroxysms in the frontal region, three (75%) developed epilepsy.
Of five patients with paroxysms in the occipital region, none developed epilepsy.
Compared with generalized EEG foci, the relative risk (RR) for patients with frontal EEG foci was 27.0.
Patients with frontal EEG paroxysms had a significantly higher risk of developing epilepsy than those with paroxysms in other regions of EEG foci (p=0.035).
These findings suggest that patients with FS presenting with frontal paroxysmal EEG abnormalities may be at risk for epilepsy. In patients with frontal paroxysmal EEG abnormalities, serial EEG should be performed, even though it does not contribute to treatment.