Abstracts

Rationale: Animal studies suggest that perinatal alterations of the stress reactivity axis can lower the seizure threshold. Human studies regarding the link between perinatal stress and seizures are sparse. Still, early life stress in humans is a known seizure precipitant, and higher levels of maternal self-reported pre / postnatal stress related symptoms can predict a younger age at first febrile seizure (FS) (Thébault-Dagher et al., Epilepsy Res, in press). We expect that alterations of the stress reactivity axis should be found in infants presenting with early childhood seizures, such as FS. Since school-age children and adolescents with stress-sensitive seizures show a blunted cortisol response (Van Campen et al., Brain, 2015, 138-8, 2234-2248), we hypothesize that infants who had FS have abnormal levels of cortisol reactivity to stress when compared to healthy infants. Methods: This was a case-control study comparing infants who had FS between the age of 10.5 and 24 months (n = 20) and matched controls (n = 18). The primary outcome was the alteration of the stress reactivity axis, as measured by salivary cortisol levels in response to a stressor (i.e. electrode placement for an electroencephalography exam). Saliva samples were collected before arriving in the exam room (M = 7.6 mins before the stressor), and 20 and 45 mins after the stressor. Cortisol levels were determined by radioimmunoassay and reactivity was assessed by finding the area under the curve with respect to ground. Three outliers were excluded and a Student’s T-Test was used to assess the difference in mean between groups. Results: The final sample was composed of 19 infants presenting with FS (10 females) and 16 healthy controls (5 females). The mean age at testing was 18.8 months (SD = 5.4). Infants presenting with FS showed lower levels of serum cortisol reactivity to experimental stress (M = 6.79, SD = 3.77) when compared to infants who did not (M = 10.49, SD = 5.64; t (33) = -2.316, p = .027), thus confirming our hypothesis. Conclusions: Our study adds to the growing body of literature showing an altered stress response in people with seizure disorders. Our results are coherent with alterations found in children with stress-sensitive seizures, and further show that an altered stress response can be measured from early infancy in infants presenting with the most common form of seizures. Lower levels of cortisol reactivity to stress could suggest a dysregulation of the stress reactivity axis, which could affect cognitive and behavioral outcome (Blair et al., 2005, Child dev, 76-3, 554-567). The benefit of interventions targeting stress symptoms from early childhood on the prognosis following seizures is unknown. Such positive impact has been shown in animal studies but remains to be assessed in human children. Funding: This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada, Fonds de Recherche du Québec Santé (FRQS), and a donation from the Jean-Pierre Hogue Foundation to Lippé, and scholarships to Thébault-Dagher from the Canadian Institutes of Health Research and the FRQ-S.