Effect of direction of head movement on motion sickness caused by Coriolis stimulation.
BACKGROUND
During constant speed rotation of the body, head rotation about an axis other than the axis of rotation of the body (i.e., Coriolis is stimulation) induces motion sickness.


OBJECTIVE
The position of the body relative to the center of rotation will influence the sickness caused by Coriolis stimulation; the direction of head movement will not affect the sickness caused by Coriolis stimulation.


METHODS
There were 24 seated subjects (12 male, 12 female) who made 30 degrees pitch motions of the head every 30 s while rotating about a vertical axis at 10 r.p.m. on a turntable at two separate locations: a) at the center of rotation; and b) 0.75 m from the center of rotation. After each head movement the subjects gave ratings of motion illness.


RESULTS
There was no significant difference between illness 0.75 m from the center of rotation and illness at the center of rotation, or between the illness ratings from male and female subjects. Moving the head up from the horizontal caused significantly fewer increases in ratings of motion illness than moving the head back down to the horizontal.


CONCLUSIONS
Precise location of the body at the center of rotation is not critical during Coriolis stimulation, but the direction of head movement has a large effect on nausea. An influence of somatosensory information on sickness caused by Coriolis stimulation is suggested.
Woodman
P D
PD
Human Factors Research Unit, University of Southampton, England.
Griffin
M J
MJ
D000328:Adult; D003312:Coriolis Force; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000209:etiology* / Q000503:physiopathology; D009068:Movement; D011187:Posture; D012399:Rotation / Q000009:adverse effects*; D012665:Semicircular Canals / Q000503:physiopathology; D012727:Sex Characteristics