Sleep apnea and excessive daytime somnolence induced by vagal nerve stimulation.

Vagal nerve stimulation (VNS) therapy affects respiration during sleep and can interrupt sleep. VNS has also been noted to improve excessive daytime sleepiness. The authors present a patient who developed excessive daytime sleepiness after VNS placement, as a consequence of apneas and arousals associated with intermittent electrical stimulation of the left vagus nerve.