Authors :
Presenting Author: Ivanna Yau, PNP – Hospital for Sick Children, Toronto
Cristina Go, MD – Hospital for Sick Children, Toronto; Puneet Jain, MD – Hospital for Sick Children, Toronto; Lyndsey Mcrae, NP – Hospital for Sick Children, Toronto; James Rutka, MD – Hospital for Sick Children, Toronto
Rationale: Vagal Nerve Stimulation (VNS) is an established treatment modality for drug resistant epilepsy (DRE). However, experience with monogenic genetic epilepsies, like STXBP1-related disorders is still evolving. Here we aim to review the effectiveness of VNS in four children with SXTBP1 Developmental and epileptic encephalopathy (SXT-DEE) from our VNS clinic.
Methods: Retrospective study review of children with STXBP1-related disorders using our Institutional VNS database from 2010 through 2023. Patient demographics, epilepsy phenotype details, VNS settings and epilepsy outcomes were extracted and summarized.
Results: Four children with STXBP1-DEE were found; three boys and one girl. Median duration of epilepsy at time of VNS placement was nine years. Median age at time of VNS implantation was ten years. All patients had daily seizures and significant neurological co-morbidities including global developmental delay (4/4), autism spectrum disorder (2/4), significant behavior issues (2/4), and dystonia (1/4). Median number of anti-seizure medications tried at time of VNS was six. Two patients had prior ketogenic diet therapy.
Median duration of follow up in VNS clinic was 2.5 years (range 0.6 – 13 years). VNS settings were optimized in 2/4 patients; one patient died of presumed SUDEP mid-titration, and one patient could not increase further as there was perceived worsening of dystonia. Two patients had > 50 % reduction in seizures as compared to baseline at one year post VNS. One patient did not require any further rescue medications in >10 years. Two patients saw improvement in their tonic and generalized tonic-clonic seizures in particular. No significant adverse effects noted in all children; one patient had mild worsening of obstructive sleep apnea that did not require intervention.
Conclusions: Children with STXBP1-DEE have known refractory seizures. Two patients had more than 50% reduction in their seizure frequency but two others saw minimal improvement. VNS may be effective in some children with STXBP1-DEE and is usually safe and well tolerated.
Funding: No funding received for this work.