1074 A Case of Obstructive Sleep Apnea Induced by a Vagus Nerve Stimulator Implanted in an Epilepsy Patient

Abstract

Introduction: Vagus nerve stimulator (VNS) devices are a treatment modality in refractory epilepsy and has been associated with the development of obstructive sleep apnea (OSA)1. VNS devices are typically implanted on the left vagus nerve, of which the left superior laryngeal nerve is a branch, and have been shown to cause left vocal cord adduction2. In some cases, adjusting VNS settings have reduced or eliminated obstructive events3. Report of Case: A 26 year-old female with refractory epilepsy underwent VNS implantation for better seizure control. Post-procedure, she reported worsening nocturnal seizures, new nocturnal choking, falling out of bed, and even started sleeping on the sofa due to safety concerns. Additionally she reported new excessive daytime sleepiness. An overnight polysomnography (PSG) showed obstructive events at evenly-spaced 108 second intervals with an overall apnea-hypopnea index of 20.9 (Figures 1,2). The frequency and length of apneas correlated with VNS settings. Continuous positive airway pressure (CPAP) titration was unsuccessful. Her neurologist adjusted her VNS device settings, but the patient relocated before repeat polysomnography and reevaluation could be performed. Conclusion(s): Our case demonstrates the obstructive sleep apnea (OSA) caused by VNS implantation resulting in worsening epilepsy symptoms. No obstructive events were observed outside of the VNS firing. Inducing OSA is a concerning complication as epilepsy control may be compromised in some VNS patients. Patients who fail CPAP therapy may need to have their VNS readjusted. Therefore, patients undergoing VNS implantation may benefit from sleep medicine evaluation due to the potential development of sleep-disordered breathing.