Subgroup analysis of seizure and cognitive outcome after vagal nerve stimulator implantation in children.

OBJECTIVE: Vagal nerve stimulator (VNS) implantation at an early age seems to lead to improved quality of life and cognitive outcome. The aim of this analysis is to evaluate whether specific patient or seizure characteristics might lead to better seizure control, cognitive outcome, and higher quality of life in children undergoing VNS implantation. METHODS: Primary outcome measure was reduction in seizure frequency. Secondary outcome measures were epilepsy outcome assessed by McHugh and Engel classifications, reduction in antiepileptic drugs (AED), developmental and cognitive outcome, as well as quality of life assessed through the pediatric quality of life (PEDSQL™) questionnaire and care giver impression (CGI) scale. Forty-five consecutive children undergoing VNS implantation were analyzed for the following subgroups: age (categorized to 1-2 years old, 3-5 years old, 6-12 years old, and 13-18 years old), sex, underlying cause (categorized to idiopathic, encephalitis, stroke, syndromic), duration of preoperative seizures (dichotomized to under or above 89 months, corresponding to the median of the whole cohort), and preoperative seizure frequency (dichotomized to under and above 360 seizures per month). RESULTS: Encephalitis as the underlying cause for seizures was the only variable significantly associated with higher reduction rate of seizure frequency. Patients with VNS implantation at the age of ≤ 2 years showed a strong association with better developmental and cognitive outcome, as well as quality of life. Shorter duration of preoperative seizures and higher preoperative seizure frequency showed a strong association with better developmental outcome, as well as quality of life. Engel outcome scores were significantly better in patients with epilepsy due to encephalitis (100% Engel I-III). However, patients with epilepsy due to encephalitis showed significantly higher complication rates (71.4%, p = 0.045). CONCLUSIONS: Children suffering from epilepsy due to encephalitis show higher seizure reduction rates after VNS implantation when compared with children suffering from epilepsy due to other causes. Developmental and cognitive outcomes as well as quality of life of children undergoing VNS implantation is strongly associated with shorter duration of preoperative seizures and implantation at a young age.

Improved quality of life and cognition after early vagal nerve stimulator implantation in children.

OBJECTIVE: In patients with drug-resistant epilepsy, reduction of seizure duration and frequency at an early age is beneficial. Vagal nerve stimulator (VNS) was shown to reduce seizure frequency and duration in children; however, data in children under the age of 12 years are sparse. The aim of this study was to compare seizure outcome and quality of life after early (≤5 years of age) and late (>5 years of age) implantation of VNS in children. METHODS: This study reviewed 45 consecutive children undergoing VNS implantation. Primary outcome measure was the reduction of seizure frequency. Secondary outcome measures were epilepsy outcome assessed by the McHugh and Engel classifications, reduction of antiepileptic drugs (AEDs), psychomotor development, and quality of life measured by the Pediatric Quality of Life (PEDSQL™) questionnaire and caregiver impression (CGI) scale. The mean follow-up time was 72.3 months (±39.8 months). RESULTS: Out of 45 patients included, in 14 (31.1%), VNS was implanted early and in 31, (68.9%) late. Reduction of seizure frequency, McHugh and Engel classifications, and reduction of AED were comparable in both groups. Quality of life measured by the CGI scale (2.1 ±â€¯1.7 in the early group vs. 3.6 ±â€¯1.6 in the late group; p = 0.004), as well as the difference of total PEDSQL™ Core scores (12.0 ±â€¯24.0 in the early group vs. -5.2 ±â€¯14.9 in the late group; p = 0.01) and cognitive PEDSQL™ Core (30.6 ±â€¯32.0 in the early group vs. 2.4 ±â€¯24.3 in the late group; p = 0.03) between preoperative and follow-up was significantly higher in the early implantation group. CONCLUSION: Early VNS implantation in children leads to a significantly better quality of life and cognitive outcome compared with late implantation while reduction of seizure frequency and epilepsy outcome seems comparable. Therefore, in children with drug-resistant epilepsy, VNS implantation should be considered as early as possible.

Early vagal nerve stimulator implantation in children: personal experience and review of the literature.

AIM: Data concerning the benefit of vagal nerve stimulation (VNS) in children under the age of 12 years is sparse. It was shown that reduction of seizure frequency and duration at an early age could lead to better psychomotor development. We therefore compare the outcome between early (≤ 5 years of age) and late (> 5 years of age) implantation of VNS in children. METHODS: This study is a prospective review of patients analyzing primarily the reduction of seizure frequency and secondarily epilepsy outcome assessed by the McHugh and Engel classification, reduction of antiepileptic drugs (AED), psychomotor development measured by the Vineland Adaptive Behavior Scale (VABS), and quality of life using the caregiver impression (CGI) scale. Mean follow-up time was 36 and 31 months in the early and late group, respectively. RESULTS: Out of 12 consecutive VNS implantations for therapy refractory epilepsy, 5 were early implantations and 7 late implantations. Reduction of seizure frequency, McHugh and Engel classification, quality of life, psychomotor development and reduction of AED were comparable in both groups. One patient in the late group suffered from a postoperative infection resulting in explanation of the VNS device and re-implantation on the opposite side, while mortality rate was 0%. CONCLUSIONS: VNS seems to be a safe and feasible therapy in children even under the age of 5 years. Responder rate, quality of life, and psychomotor development do not seem to be influenced by the child's age at implantation; however, larger studies analyzing the outcome of early VNS implantation are warranted.