Abstracts

Rationale: Vagal Nerve Stimulation (VNS) is a treatment option for refractory epilepsy in children and adults; it is also an emerging treatment for depression and other affective disorders. As psychiatric co-morbidities are common in epilepsy, there is growing interest in determining whether VNS impacts behavioral outcomes in the epilepsy population. The present study sought to determine the effect of VNS on seizure frequency (SF) and behavioral outcomes in childhood epilepsy, measured by the Strengths and Difficulties Questionnaire (SDQ) administered during screening sessions at Nationwide Children’s Hospital (NCH). Methods: Retrospective medical chart review was conducted on 61 children and adolescents (MAge= 12.43; Males=37) who received VNS treatment for epilepsy. SDQ data was acquired as part of a screening process conducted during some epilepsy clinic visits at NCH. Data on SF was available for all patients before and after VNS. In thirty-nine patients, SDQ data were available before VNS treatment and thirty-one had at least one post VNS SDQ assessment–although these were not necessarily the same individuals. The effects of VNS on SF were recorded from clinical notes and behavioral outcomes were assessed by cross sectional comparisons of pre/post SDQ scores. The raw SDQ score and number of patients above the clinical cutoff on the SDQ domains (prosocial behavior; peer relationship problems; emotion problems; conduct problems; and hyperactivity/inattention) were determined. The relation between seizure control and behavioral profile was assessed by comparing SDQ scores in VNS responders and non-responders in the post-treatment sample.   Results: In 30/61 patients (49%) an improvement in SF was found, whereas 31 patients (51%) did not show an improvement in SF. Overall, there was no difference in total SDQ scores in the pre (M=22.26, SD=7.93) vs. post (M=21.97, SD=10.76) VNS treatment groups t(74)=0.14, p=0.89. The percent of patients exceeding clinical cut-offs for problems on the social sub-scales (prosocial behavior and peer relations) was lower in the post (42%) than the pre-treatment groups (51%), though this difference was not significant. However, within the post-treatment group, clinically relevant problems on the prosocial behavior scale were not-distributed evenly between seizure control groups, χ2 (1, N=31)=7.44, p Conclusions: Our results suggest: (1) consistent with previous literature, VNS is a relatively effective means of reducing SF in about 50% of children; (2) VNS does not significantly reduce behavioral problems; (3) effective seizure management by VNS may reduce social problems—though the mechanism is unclear. The small sample size and cross sectional design indicate that results should be interpreted with caution but suggest a larger prospective study on psychosocial effects of VNS is warranted.  Funding: NCH internal funds.