Objectives Vagal nerve stimulation (VNS) is a neuromodulatory therapy indicated in drug-resistant epilepsy (DRE). Its side effects are frequently minor, however, sleep-disordered breathing (SDB) has been previously reported.¹Obstructive sleep apnoea (OSA) is highly prevalent in individuals with refractory epilepsy, and may be a cause of poor control of seizures.²

Methods Three DRE patients with active VNS underwent a video-polysomnography with 21-channel montage electroencephalography in our centre.

Results First and second patients showed OSA at the time of VNS activation. In the first patient, the apnoeic-induced arousals triggered VNS auto-firing and consequent respiratory events, perpetuating the SDB. The third patient had episodes of stridor, and an increased respiratory rate, coinciding with VNS activation. Our cases are representative of different forms of SDB that occurred as a consequence of the switch-on phase of the VNS device.

Conclusions Sleep-related breathing disturbances should be considered before VNS implantation, and should be routinely assessed after having started the therapy. Changes in stimulation parameters, and positive airway pressure therapy, may be required to treat the SDB.