Abstracts

Rationale: Febrile seizures (FS) represent the most common form of childhood seizures, affecting 2-5% of children between the ages of 6 and 24 months (Verity,1985: BMJ,290;1307-1315). These seizures are associated to a febrile illness in the absence of a Central Nervous System infection. Simple FS (SFS), characterized by brief, isolated and generalized seizures, occur in 75% of affected children and are known for their benign functional outcome. Conversely, Complex FS (CFS), characterized by either prolonged, focal or multiple seizures, which occur in 20% of affected children, may hinder cognitive development (Shinnar,2002: J. of Child Neurology,17;44-52). The cognitive outcome following CFS is however unclear to date. Although no differences have been found in global intellectual functioning between SFS and CFS, developmental delays have been noted in children having suffered a CFS as compared to a SFS (Hesdorffer,2011: Ann Neurol.70(1);93-100). Additionally, children having suffered a CFS require more academic services up to seven years following the event (Lippé,2009: Epileptic Disord.11(1);10-19). The aim of the current study was to compare the development of cognitive skills between SFS and CFS within the first year following seizure onset.Methods: An on-going prospective study has to date allowed the recruitment of 30 babies (SFS: n=17; CFS: n=13, including prolonged (n=3), multiple (n=9) and lateralized (n=1) seizures) between 6 and 24 months of age from the CHU Sainte-Justine's emergency department. Developmental evaluations were performed using the Bayley-III Scale of Infant Development, for which all three scales were administered (cognitive, language and motor) within the first year following the FS event. Statistical analyses include t-tests for group comparisons and Pearson r correlations for the evaluation of the association between developmental scores, age at seizure onset and time between seizure onset and test.Results: First, group comparisons show no statistically significant difference between SFS and CFS groups with regards to age at seizure onset (t(24)=-.2, p=.7) and time between seizure onset and test (t(24)=-.5, p=.6). Furthermore, children having suffered a SFS demonstrate a significant positive association between time between seizure onset and test and cognitive scores (r(29)=.5, p=.04), such that greater the time between seizure onset and test is associated with increased cognitive abilities. Additionally, children having suffered a CFS demonstrate a significant association between age at seizure onset and cognitive scores (r(29)=.6, p=.04), such that a younger age at seizure onset is associated with decreased cognitive abilities.Conclusions: These results suggest that cognitive abilities recover within the first year following the occurrence of a SFS, regardless of age of onset. In contrast, children having suffered a CFS will not show this recovery. Indeed, only a later age at seizure onset is shown to shield from cognitive impairment following a CFS. A longitudinal component will allow further investigation of the long-term evolution of cognitive impairments.