Impact of alignment to gravito-inertial force on motion sickness and cardiopulmonary variables.

Introduction: In tilting trains partial alignment to the gravito-inertial force (GIF) in the curves seems to be the best tilt compensation to reduce the incidence of motion sickness. We investigated the effect of alignment to the GIF on the development of motion sickness during low-frequency horizontal motion.

Methods: There were 12 healthy subjects who participated.

Respiratory impact on motion sickness induced by linear motion.

Motion sickness incidence (MSI) for vertical sinusoidal motion reaches a maximum at 0.167 Hz. Normal breathing frequency is close to this frequency.

Hyperventilation in a motion sickness desensitization program.

Introduction: In motion sickness desensitization programs, the motion sickness provocative stimulus is often a forward bending of the trunk on a rotating chair, inducing Coriolis effects. Since respiratory relaxation techniques are applied successfully in these courses, we investigated whether these repetitive trunk movements by themselves may induce hyperventilation and consequently add to the motion sickness.

Methods: There were 12 healthy subjects who participated in our study.

Motion sickness induced by optokinetic drums.

Motion sickness is not only elicited by certain kinds of self-motion, but also by motion of a visual scene. In case of the latter, optokinetic drums are often used and a visual-vestibular conflict is assumed to cause the sickness. When the rotation axis is Earth vertical however, different studies show different results.

Theoretical considerations on canal-otolith interaction and an observer model.

Subjective vertical orientation, eye and body movements, and motion sickness all depend on the way our central nervous system deals with the gravito-inertial force resolution problem: how to discern accelerations due to motion from those due to gravity, despite these accelerations being physically indistinguishable. To control body or eye movements, the accelerations due to motion should be known explicitly. Hence, somehow gravity should be filtered out of the specific force or gravito-inertial acceleration (GIA, the sum of both accelerations) as sensed by the otoliths, which are the linear accelerometers in the inner ear.