Abstracts

Rationale: Convulsive status epilepticus (CSE) is the most common neurological emergency and is thought to be associated with unfavourable developmental outcomes. This is especially true of children with a pre-existing condition. CSE associated with a prolonged febrile seizure (PFS) in normally developing children is largely thought to be innocuous. However, imaging studies have shown that close to the time of a PFS there is evidence for hippocampal injury in the form of oedema which recovers within 6 months. In this study, we investigated cognitive function close to the time of CSE and one-year later. We predicted that children with CSE associated with a PFS would perform better than children with CSE associated with other aetiologies at both time-points. We also investigated whether the developmental functions of children in the PFS group were affected close to the time of incident. Methods: Forty children underwent investigations a mean of 30 days following an episode of CSE lasting a mean of 77.6 minutes. 20 children had PFS (mean age 18 months) and 20 had CSE associated with other aetiologies (mean age 15.6 months). Fourteen children were seen at follow-up (7 associated with a PFS) a mean of 11.7 months following their initial assessment. At both test sessions the two groups did not differ in age, duration of seizure or time from seizure/previous assessment.Participants were assessed using the Bayleys Scales of Infant Development-III. Standardized indices for cognition, language and motor development were derived with a mean value of 100. Results: An independent samples t-test revealed that the PFS group performed better than the non-PFS group on the cognition (p=0.001), language (p=0.001) and motor scales (p<0.001) at the initial assessment. A similar result was obtained at the follow-up assessment with the PFS group outperforming the non-PFS group on both cognition (p=0.007) and language (p=0.003) and showing a trend for better performance on the motor scales (p=0.062). Repeated measures analysis of variance (ANOVA) analysing change in performance across the two test points revealed a significant group by time interaction (p=0.021) with the PFS group showing an increase in their mean language composite score from initial assessment to follow up (94.1 to 104.6) and the non-PFS group showing a decrease (78 to 68). Similar analyses for motor and cognitive scores were not significant. A one sample t-test showed that the PFS group’s language score at the initial assessment was significantly lower than the normative mean (p=0.007). Conclusions: As predicted, the PFS group outperformed the non-PFS group at both time points. However language abilities in the PFS group were still affected close to the time of injury. Results from our follow-up assessment suggest that language faculties in the PFS group tend to ameliorate over time whereas the opposite occurs for the non-PFS group.