Demonstrating the potential for dynamic auditory stimulation to contribute to motion sickness.

Behrang Keshavarz,Lawrence J Hettinger,Robert S Kennedy,Jennifer L Campos,Manuel S Malmierca

doi:10.1371/journal.pone.0101016

Abstract

Auditory cues can create the illusion of self-motion (vection) in the absence of visual or physical stimulation. The present study aimed to determine whether auditory cues alone can also elicit motion sickness and how auditory cues contribute to motion sickness when added to visual motion stimuli. Twenty participants were seated in front of a curved projection display and were exposed to a virtual scene that constantly rotated around the participant's vertical axis. The virtual scene contained either visual-only, auditory-only, or a combination of corresponding visual and auditory cues. All participants performed all three conditions in a counterbalanced order. Participants tilted their heads alternately towards the right or left shoulder in all conditions during stimulus exposure in order to create pseudo-Coriolis effects and to maximize the likelihood for motion sickness. Measurements of motion sickness (onset, severity), vection (latency, strength, duration), and postural steadiness (center of pressure) were recorded. Results showed that adding auditory cues to the visual stimuli did not, on average, affect motion sickness and postural steadiness, but it did reduce vection onset times and increased vection strength compared to pure visual or pure auditory stimulation. Eighteen of the 20 participants reported at least slight motion sickness in the two conditions including visual stimuli. More interestingly, six participants also reported slight motion sickness during pure auditory stimulation and two of the six participants stopped the pure auditory test session due to motion sickness. The present study is the first to demonstrate that motion sickness may be caused by pure auditory stimulation, which we refer to as “auditorily induced motion sickness”.

Highlights

Motion sickness (MS) is a well-known and widely reported malady
Participants were exposed to a constantly rotating stimulus that contained either only visual, only auditory, or a combination of corresponding visual and auditory cues. These results demonstrated that auditory cues significantly increased vection strength and reduced the onset time of vection when they were added to visual cues
ANOVAs have been shown to be robust against violations of normality when group sizes are not small

Summary

Introduction

Motion sickness (MS) is a well-known and widely reported malady. MS is a major issue among travelers (e.g., on cars, buses, trains, airplanes, or ships), and for users of virtual environments (e.g., driving simulators or gaming systems). As real physical motion is typically absent in the latter scenarios (except for motion-based simulators), MS is often referred to as being visually induced in these cases (see [1] for an overview). The ‘‘sensory conflict theory’’ [5] proposes that a mismatch between (or within) the visual, the vestibular, and/or the somatosensory senses causes MS. Based on this theory, a fixedbase simulator can cause visually induced MS due to the incongruent information delivered to the eyes (indicating selfmotion, see [6] for an overview) and the vestibular and somatosensory senses (indicating a veridical, stable, and nonmoving position). A comprehensive overview of the most prominent theories explaining MS and a critical comparison of these theories is provided by [10]

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