Effects of Vagus Nerve Stimulation on Sleep‐related Breathing in Epilepsy Patients

Purpose: To describe the effects of vagus nerve stimulation (VNS) on sleep‐related breathing in a sample of 16 epilepsy patients. Methods: Sixteen adults with medically refractory epilepsy (nine men, seven women, ages 21–58 years) underwent baseline polysomnograms (PSGs). Three months after VNS therapy was initiated, PSGs were repeated. In addition, patient 7 had a study with esophageal pressure monitoring, and patient 1 had a continuous positive airway pressure (CPAP) trial. Results: Baseline PSGs: One of 16 patients had an apnea–hypopnea index (AHI) >5 (6.8). Treatment PSGs: Five of 16 patients had treatment AHIs >5. Respiratory events were more frequent during periods with VNS activation (on‐time) than without VNS activation (off‐time; p = 0.016). Follow‐up studies: Esophageal pressure monitoring in patient 7 showed crescendos in esophageal pressure during VNS activation, supporting an obstructive pattern. The CPAP trial of patient 1 showed that all respiratory events were associated with VNS stimulation at low CPAP levels. They were resolved at higher CPAP levels. Conclusions: Treatment with VNS affects respiration during sleep and should be used with care, particularly in patients with preexisting obstructive sleep apnea. The AHI after VNS treatment remained