Could OKAN be an objective indicator of the susceptibility to visually induced motion sickness?

International Workshop Agreement 3 organized by the International Standard Organization calls for more research to determine simple objective ways to assess susceptibility to visually induce motion sickness (VIMS) without making viewers sick (So and Ujike, 2010). This study examines the use of measurable optokinetic afternystagmus (OKAN) parameters to predict susceptibility to VIMS. Eighteen participants were recruited. They were exposed to a sickness provoking virtual rotating drum (210 degrees field-of-view) with striped patterns rotating at 60 degrees per second for 30 minutes (Phase 1). Sickness data were collected before, during, and after the exposure. These participants were invited back for OKAN measurements at least two weeks after Phase 1 was completed to minimize any adaption effect (Phase 2). Out of the 18 participants, 10 participants (i.e., 55%) exhibited consistent patterns of OKAN. Correlations between the time constants of OKAN and levels of VIMS experienced by the same viewers were found. The possibility of using OKAN as an objective indicator of the susceptibility to visually induced motion sickness is discussed.