Abstracts

A number of EEG abnormalities such as spike and wave discharges, sharp waves, diffuse slowing, focal theta rhythms and photoparoxysmal reactions have been described in children with febrile seizures (FSs). Evidences suggest ictal and interictal spectral power and coherence abnormalities in patients with epilepsy. However, no studies with quantitative EEG analyses have been performed in febrile seizure patients. The aim of this study was to compare the spectral magnitude of spontaneous EEG rhythms recorded during the rest and the amplitude of steady-state visual evoked potentials (SSVEPs) elicited by the intermittent photic stimulation (IPS) in children with FSs and normal controls., EEG was recorded during the rest and the 5, 7.5,10 and 12.5 Hz IPS in fifteen 3-4 year-old children with FSs and 10 age-matched controls, as well as in twenty 5-7 year-old children with FSs and 11 controls. Fourrier transform was applied to obtain the magnitude of the spontaneous EEG spectrum and the amplitude of the SSVEPs., Our data suggest that the 3-4 year-old children with FSs show greater magnitudes of the spontaneous EEG spectra (mainly theta band) compared to controls, these differences were not observed in older children. On the contrary, 5-7-year old children show greater 7.5, 10 and 12.5 Hz SSVEPs amplitudes compared to controls, these differences being more consistent and significant over the temporal regions. The magnitude of activity in occipital and temporal regions was also assessed using a source analysis model and showed greater activation of these regions during the IPS in FSs patients., The greater amount of theta slow-wave activity in 3-4-year-old FSs patients suggests a more immature pattern of brain bioelectrical activity in these children. The persistence of immature connections could lead to neuronal networks reorganization and to more powerful responses to the IPS in older children. Prospective studies could assess whether these abnormalities have a prognostic value in the development of temporal lobe epilepsy following FSs., (Supported by Canada Research Chair program and a CFI (Canadian Foundation for Innovation) award to ML, CIHR scholarship to AB.)