Effect of Transcutaneous Vagal Nerve Stimulation on Reducing Visually Induced Motion Sickness in Healthy Volunteers

Nausea is a common and distressing experience that often precedes vomiting. Amongst symptoms emanating from the gastrointestinal (GI) tract nausea can be considered somewhat unique, as on one hand it represents a normal, highly conserved, physiological response to an ingested toxin yet on the other it may indicate pathology. Nausea may also arise as a consequence of pharmaco- and chemotherapeutic interventions. Nausea negatively impacts on quality of life, adherence to treatment and is a cause for discontinuation of the development of novel compounds. Experimentally, nausea can be induced in humans using a visually induced motion stimulus. Previously we have developed a 10-minute motion video of the landscape rotating as seen from the perspective of a subject standing on Westminster Bridge, London. The tilted and rotating view visual display makes the subject perceive that they are spinning round and round on a spot tilted away from centre of gravity due to circular vection. This motion video induced nausea in approximately 50% of healthy participants and caused a reduction in cardiac vagal tone, a validated measure of the parasympathetic nervous system branch on the autonomic nervous system. We therefore are evaluating the role of external transcutaneous vagal nerve stimulation in visually induced motion sickness.