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This study explored predictors of response to vagus nerve stimulation in childhood-onset epilepsy. This retrospective chart review included all patients with new vagus nerve stimulator insertion between January 1, 2006, and December 31, 2011. Primary outcome was change in seizure frequency classified on the International League Against Epilepsy scale. Overall, 67.4% (95% confidence limits 53.3%-81.6%) of the patients had outcome of class 4 or better, and 4 patients (9.3%, 95% confidence interval 0.5%-18.1%) achieved complete seizure freedom (mean follow-up 3.5 y). Absence of magnetic resonance imaging (MRI) lesion (odds ratio 6.068, 95% confidence interval 1.214-30.329, P = .028) and duration of epilepsy before implantation (odds ratio 1.291, 95% confidence interval 1.015-1.642, P = .038) were found to be statistically significant predictors of good outcome and provided a sufficient fit to the data (area under the receiver operating characteristic curve .80, Hosmer-Lemeshow goodness of fit P = .92). This study provides preliminary evidence that nonlesional patients are significantly more likely to have better outcome with vagus nerve stimulation. [ABSTRACT FROM PUBLISHER]

Stress is the most commonly reported precipitating factor for seizures in patients with epilepsy. Despite compelling anecdotal evidence for stress-induced seizures, animal models of the phenomena are sparse and possible mechanisms are unclear. Here, we tested the hypothesis that increased levels of the stress-associated hormone corticosterone (CORT) would increase epileptiform activity and spontaneous seizure frequency in mice rendered epileptic following pilocarpine-induced status epilepticus. We monitored video-EEG activity in pilocarpine-treated mice 24/7 for a period of four or more weeks, during which animals were serially treated with CORT or vehicle. CORT increased the frequency and duration of epileptiform events within the first 24 hours of treatment, and this effect persisted for up to two weeks following termination of CORT injections. Interestingly, vehicle injection produced a transient spike in CORT levels -- presumably due to the stress of injection -- and a modest but significant increase in epileptiform activity. Neither CORT nor vehicle treatment significantly altered seizure frequency; although a small subset of animals did appear responsive. Taken together, our findings indicate that treatment of epileptic animals with exogenous CORT designed to mimic chronic stress can induce a persistent increase in interictal epileptiform activity. [ABSTRACT FROM AUTHOR]