title: Effects of vagus nerve stimulation on sleep-related breathing in epilepsy patients.
abstract: OBJECTIVE
  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 <5 in the majority of patients and was only mildly elevated (<12) in five patients. In one patient, CPAP resolved VNS-related respiratory events.
authors.affiliation: Michael S. Aldrich Sleep Disorders Laboratory and the Epilepsy Program, Clinical Neurophysiology Section, Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, U.S.A.
authors.forename: Mary
authors.initials: M
authors.lastname: Marzec
authors.forename: Jonathan
authors.initials: J
authors.lastname: Edwards
authors.forename: Oren
authors.initials: O
authors.lastname: Sagher
authors.forename: Gail
authors.initials: G
authors.lastname: Fromes
authors.forename: Beth A
authors.initials: BA
authors.lastname: Malow
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D000927:Anticonvulsants / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000295:instrumentation; D017029:Epilepsy, Complex Partial / Q000503:physiopathology* / Q000628:therapy; D004829:Epilepsy, Generalized / Q000503:physiopathology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020190:Myoclonic Epilepsy, Juvenile / Q000503:physiopathology* / Q000628:therapy; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D019736:Prostheses and Implants; D012123:Pulmonary Ventilation / Q000502:physiology*; D017552:Solitary Nucleus / Q000503:physiopathology; D014630:Vagus Nerve / Q000503:physiopathology*
chemical_list: D000927:Anticonvulsants; D010100:Oxygen