IS VAGUS NERVE STIMULATION ASSOCIATED WITH SLEEP APNEA?
Vagus nerve stimulation (VNS), a therapy for refractory epilepsy, is associated with adverse changes in respiration during sleep, according to B. A. Malow, MD, of the University of Michigan Medical School, in Ann Arbor, and colleagues. Vagus nerve stimulation has been associated with respiratory symptoms such as dyspnea and voice alteration in humans; in animal studies, it has caused respiratory arrest, noted Dr. Malow and colleagues, whose pilot study of the effect of VNS on four patients with medically refractory epilepsy is in the November 28 Neurology. “All patients showed consistent sleep-related decreases in airflow and effort coinciding with VNS activation, although most events did not meet laboratory criteria for apneas or hypopneas,” said Dr. Malow. She noted that respiratory changes were clinically significant for the one patient with preexisting obstructive sleep apnea (OSA) and that, to such patients, VNS should be administered with care. “Lowering VNS stimulus frequency or
