Spatial task performance, sex differences, and motion sickness susceptibility.

Levine ME, Stern RM.

Department of Psychology, The Pennsylvania State University, University Park, 16802, USA. mell57 psu.edu

There are substantial individual differences in susceptibility to motion sickness, yet little is known about what mediates these differences. Spatial ability and sex have been suggested as possible factors in this relationship. 89 participants (57 women) were administered a Motion Sickness Questionnaire that assesses motion sickness susceptibility, a Water-level Task that gauges sensitivity to gravitational upright, and a Mental Rotation Task that tests an individual's awareness of how objects typically move in space. Significant sex differences were observed in performance of both the Water-level Task (p<.01), and the Mental Rotation Task (p<.005), with women performing less accurately than men. Women also had significantly higher scores on the Motion Sickness Questionnaire (p<.005). Among men, but not women, significant negative relationships were observed between Water-level Task performance and Motion Sickness Questionnaire score (p<.001) and between Mental Rotation Task performance and Motion Sickness Questionnaire score (p<.005). In conclusion, women performed significantly more poorly than men did on the spatial ability tasks and reported significantly more bouts of motion sickness. In addition, men showed a significant negative relationship between spatial ability and motion sickness susceptibility.

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Visually induced motion sickness predicted by postural instability.

Smart LJ Jr, Stoffregen TA, Bardy BG.

Department of Psychology, Miami University, Oxford, OH 45056, USA. smartlj muohio.edu

We investigated whether postural instability can predict motion sickness and studied relations among instability, motion sickness, and vection. Nine men and 4 women (mean age = 19.85 years) were exposed, while standing, to an optical simulation of body sway. Head motion was recorded using a magnetic tracking system. Postural instabilities were observed prior to the onset of motion sickness. Vection was reported by most participants, including all who became ill. A discriminant analysis revealed that parameters of postural motion accurately predicted motion sickness. The results confirm that postural instability precedes motion sickness and suggest that measures of postural motion may serve as reliable predictors of motion sickness. Potential applications of this research include the development of on-line diagnostic tools that will allow for the prevention of motion sickness in operational and training settings.

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Medical prevention of space motion sickness--animal model of therapeutic effect of a new medicine on motion sickness.

Yang TD, Pei JS, Yang SL, Liu ZQ, Sun RL.

Institute of Space Medico-Engineering, Beijing, China.

Space motion sickness (MS) is one of the most important problems in the field of space medicine. In order to prevent space MS, a new medicine, PMPA, has been prepared by means of synthesizing in our laboratory. The purposes of this study were to set up animal models of PMPA against MS, and to observe its effects on anti-MS, and to prove its function of antagonism to choline. Eight cats, forty rabbits and two hundred and ten rats were selected as animal subjects. The parallel swing stimulus, a method causing the reversal syndromes and tests of anti-choline function were used in our experiments. The results are as follows: (1) The score of MS symptoms in cats with PMPA or scopolamine (SCOP) is significantly lower than that in cats with placebo (p<0.01), while the incidences of efficiency and prevention of PMPA (87.5%, 75%) are higher than those of SCOP (75.0%, 50%) in cats. (2) PMPA of 1.6 mg/kg or 0.8 mg/kg could antagonize the reversal syndromes and repress reversal rotation significantly in rabbits like SCOP in comparison with placebo (p<0.01). (3) PMPA could inhibit tremor evoked by oxotremorine or by nicotine-procaine in rats like SCOP, and play an important role in the antagonism to central M-choline and N-choline receptors. The animal experiments demonstrate that PMPA is an effective medicine against MS with antagonism function to choline. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

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[Image and quantity analysis of prostaglandin in rats' blood plasma and Na(+)-K(+)-ATPase in their cerebellum during the prevention of motion sickness by cinnarizine]

[Article in Chinese]

Dong W, Tian D, Zhang M.

Department of Cytobiology, Naval Medical College, Nanjing 210099.

To study the mechanism of cinnarizine in preventing motion sickness, TXB2, 6-Keto-PGF1 alpha in rats' blood plasma and Na(+)-K(+)-ATPase activity in the endothelial cells of their cerebellar capillary were measured and analysed by a radioactive immunity analyser and a computer image system. The results showed that TXB2 and 6-Keto-PGF1 alpha in rats' blood plasma in the cinnarizine preventing group (CPG) decreased remarkably, compared with those in the motion sickness group(MSG) (p < 0.05). The activity of Na(+)-K(+)-ATPase in the endothelial cells of rats' cerebellar capillary in CPG was higher than that in MSG (p < 0.01). The authors suggest that the lower concentration of TXB2 and 6-Keto-PGF1 alpha in rats' blood plasma in CPG is closely related to cinnarizine which prevents Ca2+ from entering into the platelets and into the endothelial cells of blood vessels. The higher activity of Na(+)-K(+)-ATPase in the cerebellum may be caused by cinnarizene which dilates the blood vessels in the brain, increases the blood flow therein, and hinders Ca2+ from getting into the cerebellum cells. These change are believed to be the important mechanism of how cinnarizine prevents motion sickness.

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Motion sickness and vestibular hypersensitivity.

Mallinson AI, Longridge NS.

Neuro-otology Unit, Vancouver General Hospital, British Columbia.

OBJECTIVE: Motion sickness is poorly understood, although it has been recognized for years as debilitating. Vestibular function is required for motion sickness to occur, but motion sickness can also be brought on without body motion. The aim of this study was to see if there was a correlation between caloric response and motion sickness susceptibility. DESIGN: One experiment was a prospective study carried out on 200 patients. A second prospective study was carried out on 121 patients. SETTING: Patients referred to our tertiary/quaternary care dizziness clinic. METHODS: In experiment 1, caloric scores in patients were correlated with symptoms of motion sickness as established by responses to a simple question. In experiment 2, caloric scores were correlated with symptomatic responses to caloric testing itself. MAIN OUTCOME MEASURES: Caloric responses of the best ear were measured according to standardized caloric evaluation methods. RESULTS: There was no correlation between motion sickness and caloric scores. There was a significant difference in caloric scores between patients made symptomatic by calorics and those who were not. CONCLUSIONS: The autonomic response seen in some patients is not triggered by a specific level of semicircular canal response (as measured by caloric testing). We hypothesize that (similar to space motion sickness) the trigger is a signal differential that arises between semicircular canals and otoliths and that some patients are unable to suppress this response. These patients often suffer motion sickness on a long-term basis.

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Motion sickness and tilts of the inertial force environment: active suspension systems vs. active passengers.

Golding JF, Bles W, Bos JE, Haynes T, Gresty MA.

Department of Psychology, University of Westminster, London, United Kingdom. goldinj wmin.ac.uk

BACKGROUND: Maneuvering in vehicles exposes occupants to low frequency forces (< 1 Hz) which can provoke motion sickness. HYPOTHESIS: Aligning with the tilting inertial resultant (gravity + imposed horizontal acceleration: gravito-inertial force (GIF)) may reduce motion sickness when tilting is either 'active' (self-initiated; Experiment 1) or 'passive' (suspension machinery; Experiment 2). METHODS: Exp 1: Twelve seated subjects were exposed to continuous horizontal translational oscillation through the body x-axis (3.1 m x S(-2) peak acceleration, 0.20 Hz) while making head tilts which were either aligned or misaligned (180 degrees out of phase) with respect to GIF. The two sessions were one week apart at the same time of day, counterbalanced for order. Head tilts were controlled by tracking a moving LED display and head trajectory was verified by accelerometry. Motion continued until moderate nausea was achieved (motion endpoint) or until a 30 min cut-off. Exp 2: A different group of 12 subjects were exposed to continuous horizontal translational sinusoidal oscillation through the body x-axis (2.0 m x S(-2) peak acceleration, 0.176 Hz) while seated in a cab which was tilted by suspension machinery around the y-axis of the ears so that GIF was aligned or misaligned (180 degrees out of phase) with the body z-axis. RESULTS: Exp 1: Mean +/- SD time to motion endpoint was significantly longer for aligned (19.2 +/- 12.0 min) than for misaligned (17.8 +/- 13.0 min; p < 0.05, two-tail). Exp 2: Mean +/- SD time to motion endpoint was significantly shorter for aligned (21.8 +/- 10.9 min) than for misaligned (28.3 +/- 5.8 min; p < 0.01, two-tail). CONCLUSIONS: Whether or not compensatory tilting protects against (Exp 1) or contributes to (Exp 2) motion sickness may be influenced by whether the tilting is under the active control of the person (e.g., car driver) or under external control (e.g., passenger in a high-speed tilting train).

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Effect of antiemetic drugs on decrease in gastric emptying in experimental model of motion sickness in rats.

Gupta YK, Chaudhary G.

Neuropharmacology Laboratory, Department of Pharmacology, All India Institute of Medical Sciences, New Delhi 110029, India. ykg hotmail.com

AIM: To study the effect of pretreatment with different antiemetic drugs on the motion sickness-induced inhibition in gastric emptying. METHODS: The rats were rotated for a period of 45 min at the rate of 30 rotations per min. RESULTS: Rotating the rats caused a significant decrease in gastric emptying as compared to the non-rotated group. Pretreatment with scopolamine (5 mg/kg, ip) did not reverse the delay in gastric emptying, while it per se caused inhibition of gastric emptying in the non-rotated group. Similarly other drugs mepyramine, cisapride, and granisetron did not have any effect on delay in gastric emptying caused by rotation. However beta blocker propranolol could partially but significantly reverse the decrease in gastric emptying. CONCLUSION: The present study demonstrated the potential use of propranolol as adjuvant with conventional antiemetics for motion sickness to combat associated secondary symptoms.

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Effect of seating, vision and direction of horizontal oscillation on motion sickness.

Mills KL, Griffin MJ.

Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, UK.

BACKGROUND: Low frequency horizontal oscillation can cause motion sickness in some forms of transport, but the influence of the characteristics of the motion and the visual and postural conditions of the body on sickness are not known. HYPOTHESES: It was hypothesised that body position, vision and direction of motion will have an effect on motion sickness. METHOD: There were 72 seated subjects who were exposed to horizontal oscillation at 0.25 Hz, 0.7 ms(-2) r.m.s. (peak-to-peak displacement of 0.8 m) for up to 30 min while in 1 of 6 conditions. Three conditions involved fore-and-aft motion and three involved lateral motion. For motion in each axis, subjects sat within a closed cabin with either: a) a high backrest with their eyes open; b) a low backrest with their eyes open; or c) a low backrest with their eyes closed and blindfolded. Subjects provided ratings of their motion sickness symptoms at 1-min intervals during the 30-min exposures. RESULTS: The most nauseogenic stimulus was fore-and-aft motion with a low backrest and the eyes open. Self-ratings of motion sickness susceptibility provided by subjects before participating in the experiment were positively correlated with their illness ratings during the experiment. CONCLUSIONS: Restraint to the upper body during exposure to horizontal acceleration may reduce the susceptibility to motion sickness caused by horizontal oscillation. The relative nauseogenicity of fore-and-aft and lateral oscillation depends on the support given to the upper body. In the conditions of the experiment the effects of the postural support given to the subjects and their prior susceptibility to motion sickness were greater than any effect of the visual conditions.

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