Abstracts

Rationale: EEG is essential for the diagnosis of epilepsy syndromes. Ideally, EEG would show epileptiform discharges in all children with epilepsy. Routine EEG’s show epileptiform discharges in 32-44% of children with new onset seizures. Our aim was to establish whether an early postictal EEG was a more useful diagnostic tool than a late sleep-deprived(SD) EEG.Methods: Children with new onset seizures not on antiepileptic drugs were recruited. Children had an initial EEG performed within 24 hours of a seizure (early EEG), and a second SD EEG between 48 hours and 4 weeks after the seizure. All EEG's were assessed independently by two investigators whom were blind both to the type of EEG and the clinical history of the child.Results: Of 92 children, 55% had a single seizure and 45% had 2 or more seizures prior to the first EEG. Seizures were focal in 66% and generalised in 21%. Sixteen children had idiopathic generalised epilepsy, 47 idiopathic focal epilepsy, 1 symptomatic generalised epilepsy and 4 symptomatic focal epilepsy. Epileptiform discharges were found in 61% SD EEG’s and 57% early EEG’s (p=.27). Background slowing was seen in 28% SD EEG’s and 46% early EEG’s (p=.0009). Parents preferred the early EEG (71%) to SD EEG (15%) as they preferred the EEG as soon as possible after the seizure.Conclusions: In children with new onset seizures, both sleep deprived and early EEG’s show high epileptiform rates with a similar yield. Our findings suggest that either approach is better than routine EEG, and choice should be guided by patient, service and economic preference.