Abstracts

Outcome of Vagus Nerve Stimulation in Pediatric Drug Resistant Genetic Epilepsy with Monogenic Etiology

Abstract number : 1.328
Submission category : 4. Clinical Epilepsy / 4C. Clinical Treatments
Year : 2024
Submission ID : 1370
Source : www.aesnet.org
Presentation date : 12/7/2024 12:00:00 AM
Published date :

Authors :
Presenting Author: Sonali Singh, MD, DM – The Hospital for Sick Children

Ivanna Yau, NP – The Hospital for Sick Children
Lyndsey McRae, NP-PHC – The Hospital for Sick Children
Kaitlin Flynn, RN – The Hospital for Sick Children
Cristina Go, MD – BC Children's Hospital
George Ibrahim, MD, PhD – The Hospital for Sick Children
James Rutka, MD, PhD – The Hospital for Sick Children; University of Toronto
Elizabeth Donner, MD, FRCPC – Hospital for Sick Children
Puneet Jain, MD – The Hospital for Sick Children

Rationale: Vagus nerve stimulation (VNS) is a useful option in pediatric drug resistant epilepsy (DRE) population who are ineligible for resective epilepsy surgery. Monogenetic DRE is one such important group of patients undergoing VNS. Response to VNS in pediatric population is considered comparable to adults. Determinants of clinical outcome is unknow in these patients.

Methods: It is a retrospective observational study. It included all children (≤18 years), who have VNS implanted at our institution for monogenic DRE till date with at least 6 months follow up. The details of these children were collected and summarized from the electronic health record system used at our institution.

Results: 51 children had monogenic DRE and VNS implanted. At least 6 months follow details are available in 43/51. Mutations in 22 different genes were identified. SCN1A was the most common gene (14/51) followed by STXBP1 and MECP2 (5 each). The median age at seizure onset was 12 months (Range 1-132 months). Mean age at VNS implantation was 9.4 years (SD ±4). The Mean number of failed Anti-seizure medications (ASMs) was 5.3 (SD ± 2.1). Seven patients had < 3 seizure types: generalized tonic-clonic-3, focal motor-2 and both-2. Multiple seizure types (≥ 3 types) consisting of epileptic spasms, myoclonic seizures, atonic seizure, atypical absences, focal non-motor seizures, GTCs, FM seizures were present in rest (44/51). Seizure frequency at baseline was daily-weekly in all patients except one (monthly). Ketogenic diet therapy was tried in 17/51 patients. Four patients had undergone prior epilepsy surgery (Corpus callosotomy- 2; left/right temporal lobectomy-2). Median duration of follow up post VNS implant was 3 years (Range: 6m to 8 years). Patients with seizure reduction > 50% from the base line at 6m, 1yr, last follow up visit were 12/43, 16/43, 18/43 respectively. At the last follow up visit 20/43 patients (46.5%) had > 50% reduction in their most disabling seizure. A similar trend was noted in SCN1A subgroup as well. One patient with GABRG3 gene mutation was seizure free at last follow up. VNS was turned off in 4/43 (Lack of efficacy-2; lack of efficacy with mild side effects-1). The fourth patient had excessive cough immediately post-transplant (VNS turned off within a month). Minor transient side effects were cough and hoarseness of voice. Mean output current achieved at 6m, 1yr and last follow up visit were 1.29 mA (±0.48), 1.67 (± 0.58) and 2.11 (±0.54) respectively. Mean duty cycle at 6m and last follow up were 12.0 (±4.2) and 21.0 (±10.2) respectively. Unfortunately, 4/43 patients died due to causes unrelated to VNS.

Conclusions: VNS is well tolerated in pediatric DRE. Response rate of more than 50% seizure reduction from baseline was seen in 46.5% of the patients.

Funding: none

Clinical Epilepsy